Real-world experience of direct oral anticoagulant use in a single pediatric center

BACKGROUND

Pediatric venous thromboembolism has increased by 130%-200%, specifically in hospitalized children, and direct oral anticoagulants (DOACs) offer several therapeutic advantages.

METHODS

This study aims to evaluate the real-world epidemiological and outcome data from a retrospective review of pediatric patients treated with DOACs from January 1, 2013 to December 31, 2022. In this single-center, IRB-approved study, 65 patients were identified and analyzed using SPSS statistical software, and a descriptive statistical analysis was conducted.

RESULTS

Of the 65 patients, 37% were on apixaban, 61.5% were on rivaroxaban, and 1.5% were on dabigatran. Per the 2023 ISTH outcome definitions, one (2%) patient had a major bleeding episode, six (9%) had clinically relevant non-major bleeding, three (5%) patients had patient-important heavy menstrual bleeding (HMB), and one (1.5%) patient had minor bleeding. Seven (19%) of 37 postmenarchal patients had evidence of HMB. Six (9.2%) patients had recurrent venous thromboembolism while on a DOAC (one was on apixaban, and five were on rivaroxaban) and were transitioned to other forms of anticoagulation.

CONCLUSION

Thus, bleeding rates after DOAC therapy are comparable to previous DOAC trials, as well as other anticoagulants in pediatrics. HMB is an important outcome measure and should continue to be investigated. This study reports a higher rate of recurrent thrombosis (9.2%) compared to other trials. However, this observation may be attributed to patients who had ongoing risk factors, as well as a longer duration of study follow-up. Additional multicentered outcome studies evaluating DOAC use in children are needed to determine long-term recurrence and HMB risks.

Age-related variation in coagulation factors in non-valvular atrial fibrillation patients receiving direct oral anticoagulants

Age is a significant risk factor for ischemic stroke. However, the influence of aging on coagulation parameters in non-valvular atrial fibrillation (NVAF) patients treated with direct oral anticoagulants (DOACs) remains unclear. A total of 775 samples were collected from 224 NVAF patients receiving apixaban, edoxaban or rivaroxaban. The samples were categorized into three age groups: (i) ≤ 64 years, (ii) 65-74 years, and (iii) ≥ 75 years (apixaban: N = 48, 108, 119; edoxaban: N = 63, 68, 126; rivaroxaban: N = 115, 90, 38, respectively). Coagulation parameters including fibrinogen (Fbg), factor II, factor V, factor VII, factor X, and D-dimer, were compared between the three age groups for each drug. The slopes in the correlation between drug concentrations and modified diluted prothrombin time (mdPT) were also assessed. Fbg and factor V increased with age, while factor II and factor X decreased. Factor VII and D-dimer showed no significant differences across age categories. The slope in response to drug concentrations was similar between the age groups. In NVAF patients treated with apixaban, edoxaban and rivaroxaban, some coagulation parameters exhibited age-related variation. However, the response of mdPT to drug concentration was consistent across age categories.

Direct oral anticoagulants in trauma patients

PURPOSE OF REVIEW

Direct oral anticoagulants (DOACs) are increasingly prescribed for prevention of thromboembolic events. Thus, trauma care providers are facing a steadily raising number of injured patients on DOACs.

RECENT FINDINGS

Despite a predictable pharmacokinetic profile, the resulting plasma levels of trauma patients upon admission and bleeding risks remain uncertain. Therefore, recent guidelines recommend the measurement of DOAC plasma concentrations in injured patients. Alternatively, DOAC specific visco-elastic tests assays can be applied to identify DOAC patients at bleeding risk.Bleeding complications in trauma patients on DOACs are generally higher compared to nonanticoagulated subjects, but comparable to vitamin K antagonists (VKAs). In particular, a traumatic brain injury does not carry an increased risk of intracranial bleeding due to a DOAK intake compared to VKAs. Current studies demonstrated that up to 14% of patients with a hip fracture are on DOACs prior to surgery. However, the majority can be operated safely within a 24h time window without an increased bleeding rate.Specific antagonists facilitate rapid reversal of patients on DOACs. Idarucizumab for dabigatran, and andexanet alfa for apixaban and rivaroxaban have been approved for life threatening bleeding. Alternatively, prothrombin complex concentrate can be used. Dialysis is a potential treatment option for dabigatran and haemoabsorption with special filters can be applied in patients on FXa-inhibitors.

SUMMARY

Current guidelines recommend the measurement of DOAC plasma levels in trauma patients. Compared to VKAs, DOACs do not carry a higher bleeding risk. DOAC specific antagonists facilitate the individual bleeding management.

Perioperative Treatment with Rivaroxaban and Dabigatran on Changes of Coagulation and Platelet Activation Biomarkers following Left Atrial Appendage Closure

Insufficient data exist regarding the investigation of the impact of novel oral anticoagulants (NOACs) on coagulation activation biomarkers in the context of left atrial appendage closure (LAAC) and device-related thrombosis (DRT). The study was designed to investigate the changes and presence of coagulation activation biomarkers between different antithrombotic strategies following LAAC. A total of 120 nonvalvular atrial fibrillation patients intolerant of long-term anticoagulants, who underwent successful WATCHMAN closure implantation, were enrolled (rivaroxaban, n = 82; dabigatran, n = 38). Blood samples were obtained from left atrium (LA) and left atrial appendage (LAA) during the operation and fasting blood samples on the same day of LAAC and 45 days after discharge. The biochemical indicators, thrombin-antithrombin complex (TAT), soluble P-selectin (sP-selectin), von Willebrand factor (vWF), and CD40 ligand (CD40L), were measured by enzyme-linked immunosorbent assay. The primary endpoints of this study were the efficacy and safety characteristics of different antithrombotic strategies, including DRT incidence, stroke or transient ischemic attack, systemic embolism, and clinical major and nonmajor bleeding complications during the follow-up of 180 days. The results revealed that TAT, vWF, sP-selectin, and CD40L levels in vein were significantly reduced by 2.4% (p = 0.043), 5.0% (p < 0.001), 8.7% (p < 0.001), and 2.5% (p = 0.043) from their baseline levels after rivaroxaban treatment. Conversely, no significant changes were detected in the dabigatran group. Furthermore, the plasma levels of platelet activation biomarkers (CD40L and sP-selectin) in both LA and LAA groups were significantly lower after anticoagulation with rivaroxaban, as compared to dabigatran treatment (CD40L: 554.62 ± 155.54 vs. 445.02 ± 130.04 for LA p = 0.0013, 578.51 ± 156.28 vs. 480.13 ± 164.37 for LAA p = 0.0052; sP-selectin: 2849.07 ± 846.69 vs. 2225.54 ± 799.96 for LA p = 0.0105, 2915.52 ± 1402.40 vs. 2203.41 ± 1061.67 for LAA p = 0.0022). Notably, the present study suggests that rivaroxaban may be more effective in the prevention of DRT for patients undergoing LAAC.

Anticoagulation for Atrial Fibrillation: A Review of Current Literature and Views

Atrial fibrillation is a common supraventricular tachyarrhythmia with uncoordinated atrial activation and ineffective atrial contraction. This leads to an increased risk of atrial thrombi, most commonly in the left atrial appendage, and increased risks of embolic strokes and/or peripheral thromboembolism. It is associated with significant morbidity and mortality. To meet the concerns of thrombi and stroke, anticoagulation has been the mainstay for prevention and treatment thereof. Historically, anticoagulation involved the use of aspirin or vitamin K antagonists, mainly warfarin. Since early 2010s, direct oral anticoagulants (DOACs) including dabigatran, rivaroxaban, apixaban, and edoxaban have been introduced and approved for anticoagulation of atrial fibrillation. DOACs demonstrated a dramatic reduction in the rate of intracranial hemorrhage as compared to warfarin, and offer the advantages of absolution of monitoring therefore avoid the risk of hemorrhages in the context of narrow therapeutic window and under-treatment characteristic of warfarin, particularly in high-risk patients. One major concern and disadvantage for DOACs was lack of reversal agents, which have largely been ameliorated by the approval of Idarucizumab for dabigatran and Andexanet alfa for both apixaban and rivaroxaban, with Ciraparantag as a universal reversal agent for all DOACs undergoing Fast-Track Review from FDA. In this article, we will be providing a broad review of anticoagulation for atrial fibrillation with a focus on risk stratification schemes and anticoagulation agents (warfarin, aspirin, DOACs) including special clinical considerations.

Exploring the level of agreement among different drug-drug interaction checkers: a comparative study on direct oral anticoagulants

BACKGROUND

Direct oral anticoagulants (DOACs) may be involved in drug-drug interactions (DDIs) potentially increasing the risk of adverse drug reactions. This study aimed to evaluate the level of agreement among interaction checkers (ICs) and DOACs' summary of product characteristics (SPCs), in listing DDIs and in attributing DDIs' severity.

RESEARCH DESIGN AND METHODS

The level of agreement among five ICs (i.e. INTERCheck WEB, Micromedex, Lexicomp, Epocrates, and drugs.com) in identifying potential DDIs and in attributing severity categories was evaluated using Gwet's AC1 on all five ICs and by comparing groups of four- and two-pair sets of ICs.

RESULTS

A total of 486 potentially interacting drugs with dabigatran, 556 for apixaban, 444 for edoxaban, and 561 for rivaroxaban were reported. The level of agreement among the ICs in identifying potential DDIs was poor (range: 0.12-0.16). Similarly, it was low in 4 and 2 sets analyses. The level of agreement among the ICs in classifying the severity of potential DDIs was poor (range: 0.32-0.34), also in 4 and 2 sets analyses.

CONCLUSIONS

The heterogeneity among different ICs and SPCs underscores the need to standardize DDI datasets and to conduct real-world studies to generate evidence regarding the frequency and clinical relevance of potential DOAC-related DDIs.

Mortality after major bleeding in Asian atrial fibrillation patients receiving different direct oral anticoagulants: a nationwide, propensity score study

In this research, we assessed mortality after major bleeding events in atrial fibrillation (AF) patients taking four direct oral anticoagulants (DOACs). Drawing data from the Taiwan National Health Insurance Research Database between 2016 and 2019, we focused on AF patients on DOACs who had major bleeding episodes. Using propensity score stabilized weighting, we established four comparable pseudo-DOAC groups. Among 2770 patients (460 dabigatran, 1322 rivaroxaban, 548 apixaban, 440 edoxaban), 85.3% were prescribed low-dose regimens. The 7-day mortality rate was 9.0%, surging to 16.0% by the 30th day. Compared with dabigatran, there was a distinct divergence in 7-day mortality of factor Xa inhibitors (p = 0.012), with hazard ratios of 1.83 (95% CI 1.11-3.00, p = 0.017) for rivaroxaban, 2.13 (95% CI 1.23-3.66, p = 0.007) for apixaban, and 2.41 (95% CI 1.39-4.19, p = 0.002) for edoxaban. This pattern remained consistent when analyzing the subgroup that received lower dosages of DOACs. In conclusion, factor Xa inhibitors were associated with a significantly higher risk of 7-day mortality following major bleeding events than dabigatran among AF patients.

Adherence, persistence and switching rates of apixaban, dabigatran and rivaroxaban in non-valvular atrial fibrillation: a multicentre real-life analysis at 3 years

INTRODUCTION

Adherence to and persistence with long-term treatment with oral anticoagulants play a significant role in preventing adverse events and mortality in patients with cardiac conditions. The aim of this study was to evaluate the adherence, persistence and switching rate at 3 years in real-life patients with non-valvular atrial fibrillation receiving treatment with first-line new oral anticoagulants.

METHODS

The study assessed all patients treated with drugs with the ATC codes B01AA, B01AE, B01AF and dispensed in pharmacies in the Lanciano-Vasto-Chieti and Pescara Local Health Units from 1 January 2011 to 30 September 2021. Adherence was calculated as the proportion of days covered; persistence was calculated as the difference in days between the start and end of treatment; and the switching rate was calculated as the difference in days between the start of treatment and the switch.

RESULTS

A total of 4270 patients were analysed. The absolute adherence figure at 3 years was 0.85. The lowest adherence levels were found in patients treated with dabigatran with an absolute value of 0.72, while the highest levels were found in patients treated with rivaroxaban with an absolute value at 3 years of 0.88. The persistence curves at 3 years of treatment with dabigatran showed a statistically significant difference (p<0.0001) compared with those of rivaroxaban and apixaban.

CONCLUSIONS

The data collected over a 3-year period showed that adherence and persistence levels and switch data were optimal and comparable in patients with non-valvular atrial fibrillation receiving treatment with either rivaroxaban or apixaban. In contrast, patients treated with dabigatran had worrying adherence and persistence levels.

Dabigatran for Treatment and Secondary Prevention of Venous Thromboembolism in Pediatric Congenital Heart Disease

BACKGROUND

Congenital heart disease (CHD) is common in children and associated with greater risk of thrombotic complications. Management of these complications with standard-of-care treatment is suboptimal for these children.

METHODS AND RESULTS

The effectiveness and safety of dabigatran were demonstrated in pivotal pediatric studies for the treatment of acute venous thromboembolism (VTE; NCT01895777) and secondary VTE prevention (NCT02197416). We report safety and efficacy outcomes from subgroup analyses of these studies for children with CHD (diagnosed according to local practice) and those without. In NCT01895777, 17/21 (81.0%) and 16/27 (59.3%) patients with CHD (including cyanotic) treated with dabigatran and standard of care, respectively, met the primary end point (complete thrombus resolution, freedom from recurrent VTE, and freedom from VTE-related death; odds ratio [OR], 0.34 [95% CI, 0.08-1.23]). In patients without CHD, 41.0% (n=64) versus 34.9% (n=22) achieved this end point with the respective treatments (OR, 0.77 [95% CI, 0.42-1.41]). Although numerical differences were observed, no heterogeneity in treatment effect of dabigatran on the composite primary end point was detected in patients with and without CHD (interaction P =0.2674). In NCT02197416, recurrent VTE at 12 months occurred in 0/17 patients with CHD versus 3/194 (1.5%) without. No patient with CHD experienced major or clinically relevant nonmajor bleeding events.

CONCLUSIONS

Data on favorable anticoagulant alternatives for the unmet needs of children with CHD are emerging, and our exploratory results suggest that dabigatran could be an appropriate treatment choice, although challenging sample size limitations in pediatric studies require cautious interpretation of findings.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01895777, NCT02197416.

The Impact of Polypharmacy on the Effectiveness and Safety of Non-vitamin K Antagonist Oral Anticoagulants in Patients with Atrial Fibrillation

BACKGROUND

 Polypharmacy may affect outcomes in patients with atrial fibrillation (AF) using non-vitamin K antagonist oral anticoagulants (NOACs) or vitamin K antagonists (VKAs) due to interactions or reduced adherence, but comparative data are lacking. Therefore, the impact of polypharmacy on AF-related outcomes and benefit-risk profiles of NOACs in patients with polypharmacy were investigated.

METHODS

 AF patients initiating anticoagulation between 2013 and 2019 were included using Belgian nationwide data. Inverse probability of treatment weighted Cox regression was used to investigate outcomes.

RESULTS

 Among 254,478 AF patients, 167,847 (66.0%) used ≥5 drugs. Polypharmacy was associated with higher stroke or systemic embolism (stroke/SE) (adjusted hazard ratio [aHR]: 1.08, 95% confidence interval [CI]: 1.02-1.15), all-cause mortality (aHR: 1.45, 95% CI: 1.40-1.50), and major bleeding risks (aHR: 1.29, 95% CI: 1.23-1.35). Among patients with polypharmacy, NOACs were associated with lower stroke/SE (aHR: 0.68, 95% CI: 0.63-0.73), all-cause mortality (aHR: 0.80, 95% CI: 0.77-0.84), major bleeding (aHR: 0.92, 95% CI: 0.87-0.97), and intracranial bleeding risks (aHR: 0.77, 95% CI: 0.69-0.85), but higher gastrointestinal bleeding risks (aHR: 1.10, 95% CI: 1.01-1.19) compared to VKAs. Major bleeding risks were lower with apixaban (aHR: 0.79, 95% CI: 0.74-0.85), but nonsignificantly different with other NOACs compared to VKAs. Lower major bleeding risks were observed with dabigatran (aHR: 0.91, 95% CI: 0.85-0.97) and apixaban (aHR: 0.77, 95% CI: 0.73-0.81) compared to rivaroxaban, and with apixaban compared to dabigatran (HR: 0.83, 95% CI: 0.77-0.90) and edoxaban (HR: 0.77, 95% CI: 0.70-0.85).

CONCLUSION

 Polypharmacy was associated with increased thromboembolic, bleeding, and mortality risks in AF patients. NOACs had better benefit-risk profiles than VKAs in patients with polypharmacy.

An Analysis of Delayed Bleeding in Cases of Colorectal Endoscopic Submucosal Dissection Due to Types of Direct Oral Anticoagulants in Japan

BACKGROUND & AIMS

Reported rates of delayed bleeding (DB) after endoscopic resection using direct oral anticoagulants (DOACs) are high and heterogeneous. This large-scale multicenter study analyzed cases of DB after colorectal endoscopic submucosal dissection related to various types of DOACs in Japan (the ABCD-J study) with those associated with warfarin.

METHODS

We retrospectively reviewed 1019 lesions in patients treated with DOACs and 459 lesions in patients treated with warfarin among 34,455 endoscopic submucosal dissection cases from 47 Japanese institutions between 2012 and 2021. The DB rate (DBR) with each DOAC was compared with that with warfarin. Risk factors for DB in patients treated with DOACs or warfarin were also investigated.

RESULTS

The mean tumor sizes in the DOAC and warfarin groups were 29.6 ± 14.0 and 30.3 ± 16.4 mm, respectively. In the DOAC group, the DBR with dabigatran (18.26%) was significantly higher than that with apixaban (10.08%, P = .029), edoxaban (7.73%, P = .001), and rivaroxaban (7.21%, P < .001). Only rivaroxaban showed a significantly lower DBR than warfarin (11.76%, P = .033). In the multivariate analysis, heparin bridging therapy (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.27-3.73, P = .005), rectal location (2.01, 1.28-3.16, P = .002), and procedure time ≥55 minutes (2.43, 1.49-3.95, P < .001) were significant risk factors for DB in the DOAC group. The DB risk in the DOAC group (OR, (95% CI)) was 2.13 (1.30-3.50) and 4.53 (2.52-8.15) for 1 and 2 significant risk factors, respectively.

CONCLUSIONS

Dabigatran was associated with a higher DBR than other DOACs, and only rivaroxaban was associated with a significantly lower DBR than warfarin.

Impact of frailty on the effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation: a nationwide cohort study

AIMS

Data on non-vitamin K antagonist oral anticoagulants (NOACs) use in patients with atrial fibrillation (AF) and frailty are scarce. Therefore, the impact of frailty on AF-related outcomes and benefit-risk profiles of NOACs in patients with frailty were investigated.

METHODS AND RESULTS

AF patients initiating anticoagulation between 2013 and 2019 were included using Belgian nationwide data. Frailty was assessed with the Claims-based Frailty Indicator. Among 254 478 anticoagulated AF patients, 71 638 (28.2%) had frailty. Frailty was associated with higher all-cause mortality risks [adjusted hazard ratio (aHR) 1.48, 95% confidence interval (CI) (1.43-1.54)], but not with thromboembolism or bleeding. Among subjects with frailty (78 080 person-years of follow-up), NOACs were associated with lower risks of stroke or systemic embolism (stroke/SE) [aHR 0.77, 95%CI (0.70-0.86)], all-cause mortality [aHR 0.88, 95%CI (0.84-0.92)], and intracranial bleeding [aHR 0.78, 95%CI (0.66-0.91)], a similar major bleeding risk [aHR 1.01, 95%CI (0.93-1.09)], and higher gastrointestinal bleeding risk [aHR 1.19, 95%CI (1.06-1.33)] compared with VKAs. Major bleeding risks were lower with apixaban [aHR 0.84, 95%CI (0.76-0.93)], similar with edoxaban [aHR 0.91, 95%CI (0.73-1.14)], and higher with dabigatran [aHR 1.16, 95%CI (1.03-1.30)] and rivaroxaban [aHR 1.11, 95%CI (1.02-1.21)] compared with VKAs. Apixaban was associated with lower major bleeding risks compared with dabigatran [aHR 0.72, 95%CI (0.65-0.80)], rivaroxaban [aHR 0.78, 95%CI (0.72-0.84)] and edoxaban [aHR 0.74, 95%CI (0.65-0.84)], but mortality risk was higher compared with dabigatran and edoxaban.

CONCLUSION

Frailty was an independent risk factor of death. Non-vitamin K antagonist oral anticoagulants had better benefit-risk profiles than VKAs in patients with frailty, especially apixaban, followed by edoxaban.

Antithrombotic Usage, Including Three-Year Outcomes With Dabigatran and Vitamin K Antagonists for Atrial Fibrillation, in Eastern Europe: A Descriptive Analysis From Phase 3 of the GLORIA-AF Registry

BACKGROUND

Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) is a prospective registry of outcomes from patients with newly diagnosed AF at risk of stroke. In the propensity score (PS)-matched global population of phase 3 GLORIA-AF, at 3 years, dabigatran-treated patients experienced reduced risk for major bleeding, and similar risk for stroke and myocardial infarction, compared with vitamin K antagonist (VKA)-treated patients.

STUDY QUESTION

Do patients in Eastern Europe benefit from treatment with dabigatran versus VKA?

STUDY DESIGN

Descriptive analysis, without PS matching. To contextualize the Eastern Europe results of GLORIA-AF phase 3, we also descriptively analyzed the global population without PS matching. Consecutive patients with newly diagnosed AF and CHA2DS2-VASc-score ≥1 were enrolled until December 2016 in 38 countries (9 in Eastern Europe).

MEASURES AND OUTCOMES

Three-year outcomes with dabigatran and VKA.

RESULTS

In Eastern Europe, 1341 patients were eligible (6% of patients globally), and incidence rates (per 100 patient-years) for the following outcomes were numerically lower with dabigatran (N = 498) versus VKA (N = 466): major bleeding (0.26 vs. 0.90), all-cause death (2.04 vs. 3.50), and a composite of stroke, systemic embolism, myocardial infarction, life-threatening bleeding, and vascular death (1.37 vs. 1.92); stroke was comparable (0.51 vs. 0.50). All incidence rates were numerically lower in Eastern Europe versus the global population for both treatments. Chronic concomitant use of high bleeding risk medications (eg, nonsteroidal anti-inflammatories) was lower in Eastern Europe (dabigatran 3.8%, VKA 9.3%) than globally (dabigatran 14.8%, VKA 20.6%) and persistence with dabigatran was higher in Eastern Europe (76%) than globally (64%).

CONCLUSIONS

Dabigatran was associated with numerically reduced major bleeding, all-cause death, and cardiovascular (CV) composite, with comparable risk of stroke versus VKA, in Eastern Europe. Limitations of this descriptive analysis include few CV events (n = 11 for stroke, in the dabigatran and VKA groups combined) and a lack of statistical analysis and PS matching, which precludes definitive conclusions; however, the CV outcomes in Eastern Europe were consistent with the beneficial impact of dabigatran versus VKA in the statistically analyzed global population with PS matching.

Comparing Efficacy and Safety Between Patients With Atrial Fibrillation Taking Direct Oral Anticoagulants or Warfarin After Direct Oral Anticoagulant Failure

BACKGROUND

An increased risk of recurrent stroke is noted in patients with atrial fibrillation despite direct oral anticoagulant (DOAC) use. We investigated the efficacy and safety of treatment with each of 4 different DOACs or warfarin after DOAC failure.

METHODS AND RESULTS

We retrospectively analyzed patients with atrial fibrillation with ischemic stroke despite DOAC treatment between January 2002 and December 2016. The different outcomes of patients with DOAC failure were compared, including recurrent ischemic stroke, major cardiovascular events, intracranial hemorrhage and subarachnoid hemorrhage, mortality, and net composite outcomes according to switching to different DOACs or vitamin K antagonist after index ischemic stroke. We identified 3759 patients with DOAC failure. A total of 84 patients experienced recurrent ischemic stroke after switching to different oral anticoagulants, with a total follow-up time of 14 years. Using the vitamin K antagonist group as a reference, switching to any of the 4 DOACs was associated with a 69% to 77% reduced risk of major cardiovascular events (adjusted hazard ratio [aHR], 0.25 [95% CI, 0.16-0.39] for apixaban, 0.23 [95% CI, 0.14-0.37] for dabigatran, 0.23 [95% CI, 0.09-0.60] for edoxaban, and 0.31 [95% CI, 0.21-0.45] for rivaroxaban), and a 69% to 83% reduced risk of net composite outcomes (aHR, 0.25 [95% CI, 0.18-0.35] for apixaban, 0.17 [95% CI, 0.11-0.25] for dabigatran, 0.31 [95% CI, 0.17-0.56] for edoxaban, and 0.31 [95% CI, 0.23-0.41] for rivaroxaban).

CONCLUSIONS

In Asian patients with DOAC failure, continuing DOACs after index stroke was associated with fewer undesirable outcomes than switching to a vitamin K antagonist. Alternative pharmacologic and nonpharmacologic strategies warrant investigation.

Early or late initiation of dabigatran versus vitamin-K-antagonists in acute ischemic stroke or TIA: The PRODAST study

BACKGROUND

The optimal timing of initiating or resuming anticoagulation after acute ischemic stroke (AIS) or transient ischemic attack (TIA) in patients with atrial fibrillation (AF) is debated. Dabigatran, a non-vitamin K oral anticoagulant (NOAC), has shown superiority against vitamin K antagonists (VKA) regarding hemorrhagic complications.

AIMS

In this registry study, we investigated the initiation of dabigatran in the early phase after AIS or TIA.

METHODS

PRODAST (Prospective Record of the Use of Dabigatran in Patients with Acute Stroke or TIA) is a prospective, multicenter, observational, post-authorization safety study. We recruited 10,039 patients at 86 German stroke units between July 2015 and November 2020. A total of 3,312 patients were treated with dabigatran or VKA and were eligible for the analysis that investigates risks for major hemorrhagic events within 3 months after early (⩽ 7 days) or late (> 7 days) initiation of dabigatran or VKA initiated at any time. Further endpoints were recurrent stroke, ischemic stroke, TIA, systemic embolism, myocardial infarction, death, and a composite endpoint of stroke, systemic embolism, life-threatening bleeding and death.

RESULTS

Major bleeding event rates per 10,000 treatment days ranged from 1.9 for late administered dabigatran to 4.9 for VKA. Early or late initiation of dabigatran was associated with a lower hazard for major hemorrhages as compared to VKA use. The difference was pronounced for intracranial hemorrhages with an adjusted hazard ratio (HR) of 0.47 (95% confidence interval (CI): 0.10-2.21) for early dabigatran use versus VKA use and an adjusted HR of 0.09 (95% CI: 0.00-13.11) for late dabigatran use versus VKA use. No differences were found between early initiation of dabigatran versus VKA use regarding ischemic endpoints.

CONCLUSIONS

The early application of dabigatran appears to be safer than VKA administered at any time point with regards to the risk of hemorrhagic complications and in particular for intracranial hemorrhage. This result, however, must be interpreted with caution in view of the low precision of the estimate.

Gastrointestinal bleeding with direct oral anticoagulants in patients with atrial fibrillation and anaemia

INTRODUCTION

A high risk of gastrointestinal bleeding has been reported with the use of some direct oral anticoagulants (DOACs). This risk may be of particular concern in individuals with associated anaemia. The aim of this study is to investigate potential differences in the risks of gastrointestinal bleeding and stroke among the four available DOACs in patients with atrial fibrillation (AF) and moderate or severe anaemia.

MATERIALS AND METHODS

All Danish patients diagnosed with incident AF who had a baseline haemoglobin measurement and subsequently initiated DOAC therapy between 2012 and 2021 were identified through administrative registries. Only patients with moderate or severe anaemia (N = 7269) were included and evaluated regarding the risk of hospitalization for gastrointestinal bleeding and stroke. Standardized absolute 1-year risks of stroke and gastrointestinal bleeding were calculated from multivariable Cox regression analyses. DOACs were compared pairwise RESULTS: Compared with apixaban, both dabigatran and rivaroxaban were associated with a significantly increased risk of gastrointestinal bleeding with standardized 1-year risk ratios of 1.73 (95 % confidence interval [CI], 1.10-2.35) and 1.56 (95 % CI, 1.18-1.93), respectively, while no significant difference was seen in the comparison of apixaban with edoxaban 1.32 (95 % CI, 0.41-2.32). No significant differences in gastrointestinal bleeding were observed with pairwise comparisons of dabigatran, rivaroxaban and edoxaban. Finally, no significant difference in stroke risk among the four DOACs was observed.

CONCLUSION

In AF patients with moderate or severe anaemia, apixaban was associated with a significantly lower risk of gastrointestinal bleeding than dabigatran and rivaroxaban. No significant difference in stroke risk was observed across all four available DOACs.

Anticoagulation in Patients with Chronic Kidney Disease

BACKGROUND

Both atrial fibrillation and venous thromboembolism (VTE) are highly prevalent among patients with chronic kidney disease (CKD). Until recently, warfarin was the most commonly prescribed oral anticoagulant. Direct oral anticoagulants (DOACs) have important advantages and have been shown to be noninferior to warfarin with respect to stroke prevention or recurrent VTE in the general population, with lower bleeding rates. This review article will provide available evidence on the use of DOACs in patients with CKD.

SUMMARY

In post hoc analyses of major randomized studies with DOACs for stroke prevention in atrial fibrillation, in the subgroup of participants with moderate CKD, defined as a creatinine clearance (CrCl) of 30-50 mL/min, dabigatran 150 mg and apixaban were associated with lower rates of stroke and systemic embolism, whereas apixaban and edoxaban were associated with lower bleeding and mortality rates, compared with warfarin. In retrospective observational studies in patients with advanced CKD (defined as a CrCl <30 mL/min) and atrial fibrillation, DOACs had similar efficacy with warfarin with numerically lower bleeding rates. All agents warrant dose adjustment in moderate-to-severe CKD. In patients on maintenance dialysis, the VALKYRIE trial, which was designed initially to study the effect of vitamin K on vascular calcification progression, established superiority for rivaroxaban compared with a vitamin K antagonist (VKA) in the extension phase. Two other clinical trials using apixaban (AXADIA and RENAL-AF) in this population were inconclusive due to recruitment challenges and low event rates. In post hoc analyses of randomized studies with DOACs in patients with VTE, in the subgroup of participants with moderate CKD at baseline, edoxaban was associated with lower rates of recurrent VTE, whereas rivaroxaban and dabigatran were associated with lower and higher bleeding rates, respectively, as compared to warfarin.

KEY MESSAGES

DOACs have revolutionized the management of atrial fibrillation and VTE, and they should be preferred over warfarin in patients with moderate-to-severe CKD with appropriate dose adjustment. Therapeutic drug monitoring with a valid technique may be considered to guide clinical management in individualized cases. Current evidence questions the need for oral anticoagulation in patients on maintenance dialysis with atrial fibrillation as both DOACs and VKAs are associated with high rates of major bleeding.

Reversing dabigatran effect with idarucizumab to enable intravenous thrombolysis in patients with acute ischaemic stroke - a single centre experience

INTRODUCTION

Our study analysed the safety and effectiveness of idarucizumab in enabling intravenous thrombolysis (IVT) in dabigatran-treated patients with acute ischaemic stroke (AIS).

CLINICAL RATIONALE FOR THE STUDY

New oral anticoagulants (NOAC), including dabigatran, are the first-choice treatment option for preventing ischaemic stroke in patients with non-valvular atrial fibrillation (AF). However, a significant percentage of AF patients develops AIS despite NOAC treatment. According to current guidelines, treatment with IVT is contraindicated in patients who have received NOAC within the last 48 hours. Idarucizumab is a fragment of a monoclonal antibody that reverses the anticoagulation effect of dabigatran. The latest research shows that it can enable safe and successful IVT in patients with recent dabigatran intake, but more data is needed to confirm the safety and effectiveness of such treatment.

MATERIAL AND METHODS

Our study included dabigatran-treated patients who received idarucizumab to allow AIS treatment with IVT in the University Hospital in Kraków (Poland) from December 2018 to June 2023. We gathered data on their past medical history, stroke severity, course of treatment and outcomes as defined by modified Rankin Scale (mRS) and National Institutes of Health Stroke Scale (NIHSS) scores at discharge. A good functional outcome was defined as mRS 0-2 points at discharge.

RESULTS

This observational study included 19 patients (13 male and six female) with a median age of 74 (IQR = 13) years. In all patients (100%), the reason for dabigatran treatment was AF. A good functional outcome after treatment (mRS 0-2) was achieved in 68.4% of patients, but mRS was already ≥ 3 points before stroke onset in three (15.8%) patients. Haemorrhagic transformation of stroke occurred in three (15.8%) patients, including symptomatic intracranial haemorrhage in two (10.5%). The mortality rate was 5.3%.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Our study results are in line with previous research on this topic, showing that IVT after idarucizumab can be successfully administered and is reasonably safe in dabigatran-treated patients with AIS.

Effects of nirmatrelvir/ritonavir on midazolam and dabigatran pharmacokinetics in healthy participants

AIMS

To evaluate pharmacokinetics (PK) and safety after coadministration of nirmatrelvir/ritonavir or ritonavir alone with midazolam (a cytochrome P450 3A4 substrate) and dabigatran (a P-glycoprotein substrate).

METHODS

PK was studied in 2 phase 1, open-label, fixed-sequence studies in healthy adults. Single oral doses of midazolam 2 mg (n = 12) or dabigatran 75 mg (n = 24) were administered alone and after steady state (i.e. ≥2 days) of nirmatrelvir/ritonavir 300 mg/100 mg and ritonavir 100 mg. Midazolam and dabigatran plasma concentrations and adverse events were analysed for each treatment.

RESULTS

After administration of midazolam with nirmatrelvir/ritonavir (test) or alone (reference), midazolam geometric mean area under the concentration-time curve extrapolated to infinity (AUCinf ) and maximum plasma concentration (Cmax ) increased 14.3-fold and 3.7-fold, respectively. Midazolam coadministered with ritonavir (test) or alone (reference) resulted in 16.5-fold and 3.9-fold increases in midazolam geometric mean AUCinf and Cmax , respectively. After administration of dabigatran with nirmatrelvir/ritonavir (test) or alone (reference), dabigatran geometric mean AUCinf and Cmax increased 1.9-fold and 2.3-fold, respectively. Dabigatran coadministered with ritonavir (test) or alone (reference) resulted in a 1.7-fold increase in dabigatran geometric mean AUCinf and Cmax . Midazolam or dabigatran exposures were generally comparable when coadministered with nirmatrelvir/ritonavir or ritonavir alone, with a slightly higher dabigatran Cmax with nirmatrelvir/ritonavir vs. ritonavir alone. Nirmatrelvir/ritonavir was generally safe when administered with or without midazolam or dabigatran. No serious or severe adverse events were reported.

CONCLUSION

Coadministration of midazolam or dabigatran with nirmatrelvir/ritonavir increased systemic exposure of midazolam or dabigatran. Midazolam exposures were comparable when coadministered with nirmatrelvir/ritonavir or ritonavir alone, suggesting no incremental effect of nirmatrelvir. Dabigatran Cmax was slightly higher when coadministered with nirmatrelvir/ritonavir compared with of ritonavir alone, suggesting a minor incremental effect of nirmatrelvir.

Effect of Daridorexant on the Pharmacokinetics of P-Glycoprotein Substrate Dabigatran Etexilate and Breast Cancer Resistance Protein Substrate Rosuvastatin in Healthy Subjects

BACKGROUND AND OBJECTIVE

The dual orexin receptor antagonist daridorexant was approved in 2022 for the treatment of insomnia at doses up to 50 mg once per night. This study aimed at investigating the effect of daridorexant 50 mg at steady state on the pharmacokinetics of dabigatran, the active moiety of dabigatran etexilate, and rosuvastatin, sensitive substrates of P-glycoprotein and breast cancer resistance protein, respectively.

METHODS

This single-center, open-label, fixed-sequence study enrolled 24 healthy male subjects who were dosed orally with dabigatran etexilate 75 mg on days 1 (Treatment A1) and 9 (Treatment C1) as well as rosuvastatin 10 mg on days 3 (Treatment A2) and 11 (Treatment C2). On days 7-14, daridorexant (50 mg once daily) was administered. Blood samples for the pharmacokinetics of both substrates and the pharmacodynamics of dabigatran, i.e., two coagulation tests, were collected and safety assessments performed. Noncompartmental pharmacokinetic parameters and pharmacodynamic variables were evaluated with geometric mean ratios and 90% confidence intervals of Treatment C1/C2 versus A1/A2.

RESULTS

Geometric mean ratios (90% confidence interval) of dabigatran maximum plasma concentration and area under the plasma concentration-time curve were 1.3 (1.0-1.7) and 1.4 (1.1-1.9), respectively, whereas the time to maximum plasma concentration and terminal half-life were comparable between treatments. Pharmacodynamic variables showed a similar pattern as dabigatran pharmacokinetics in both treatments. Rosuvastatin pharmacokinetics were unchanged upon concomitant daridorexant administration. All treatments were well tolerated.

CONCLUSIONS

A mild inhibition of P-glycoprotein was observed after administration of daridorexant (50 mg once daily) at steady state, whereas breast cancer resistance protein was not affected.

CLINICAL TRIAL REGISTRATION

NCT05480475; date of registration: 29 July, 2022.

Direct oral anticoagulants for deep vein thrombosis among patients with hereditary thrombophilia-A cohort study

OBJECTIVES

to evaluate direct oral anticoagulants (DOACs) in patients with hereditary thrombophilia and deep venous thrombosis (DVT).

METHODS

This is a retrospective observational study.

RESULTS

In total, 45 patients were treated between 01/2012 and 12/2022 (mean follow-up: 1.5 +/- 0.3 years). The most frequent thrombophilias were heterozygous V Leiden (20%), heterozygous MTHFR C677T (37.8%), heterozygous MTHFR A1298C (24.4%), and hyperhomocysteinemia (26.7%). The patients received rivaroxaban (n = 19), apixaban (n = 15), and dabigatran (n = 11). Three cases presented symptoms' recurrence without evidence of thrombosis' recurrence (two under rivaroxaban and one under apixaban; p > .05). These patients improved under parenteral anticoagulation and were further treated with dabigatran. No other event or major bleeding occurred during the follow-up. The presence of more than two factors was associated with acute recurrence of symptoms (OR = 25.9; 95% CI [1.454-461.262]; p = .026).

CONCLUSIONS

DOACs seem to be safe and efficient for patients with hereditary thrombophilia and DVT. The presence of more than two thrombophilia factors is associated with a higher risk for symptom recurrence. Although statistically non-significant, symptoms' recurrence was also observed more frequently among patients under anti-Xa inhibitors than antithrombin inhibitors. This should be verified in larger comparative studies.

Treatment of dabigatran intoxication in critically ill patients with Acute Kidney Injury: The role of Sustained Low-Efficiency Dialysis

The use of dabigatran in patients with non-valvular atrial fibrillation (AF) has widely increased in the last decades, due to its positive effects in terms of safety/efficacy. However, because of the risk of major bleeding, a great degree of attention has been suggested in elderly patients with multiple comorbidities. Notably, dabigatran mainly undergoes renal elimination and dose adjustment is recommended in patients with Chronic Kidney Disease (CKD). In this regard, the onset of an abrupt decrease of kidney function may further affect dabigatran pharmacokinetic profile, increasing the risk of acute intoxication. Idarucizumab is the approved antagonist in the case of dabigatran-associated major bleeding or concomitant need of urgent surgery, but its clinical use is limited by the lack of data in patients with Acute Kidney Injury (AKI). Thus, the early start of Extracorporeal Kidney Replacement Therapy (EKRT) could be indicated to remove the drug and to reverse the associated excess anticoagulation. Sustained Low-Efficiency Dialysis (SLED) could represent an effective therapeutic option to reduce the dabigatran plasma levels rapidly while avoiding post-treatment rebound. We present here a case series of three AKI patients with acute dabigatran intoxication, effectively and safely resolved with a single SLED session.

Predicting Treatment Effects of a New-to-Market Drug in Clinical Practice Based on Phase III Randomized Trial Results

Trial results may not be generalizable to target populations treated in clinical practice with different distributions of baseline characteristics that modify the treatment effect. We used outcome models developed with trial data to predict treatment effects in Medicare populations. We used data from the Randomized Evaluation of Long-Term Anticoagulation Therapy trial (RE-LY), which investigated the effect of dabigatran vs. warfarin on stroke or systemic embolism (stroke/SE) among patients with atrial fibrillation. We developed outcome models by fitting proportional hazards models in trial data. Target populations were trial-eligible Medicare beneficiaries who initiated dabigatran or warfarin in 2010-2011 ("early") and 2010-2017 ("extended"). We predicted 2-year risk ratios (RRs) and risk differences (RDs) for stroke/SE, major bleeding, and all-cause death in the Medicare populations using the observed baseline characteristics. The trial and early target populations had similar mean (SD) CHADS2 scores (2.15 (SD 1.13) vs. 2.15 (SD 0.91)) but different mean ages (71 vs. 79 years). Compared with RE-LY, the early Medicare population had similar predicted benefit of dabigatran vs. warfarin for stroke/SE (trial RR = 0.63, 95% confidence interval (CI) = 0.50 to 0.76 and RD = -1.37%, -1.96% to -0.77%, Medicare RR = 0.73, 0.65 to 0.82 and RD = -0.92%, -1.26% to -0.59%) and risks for major bleeding and all-cause death. The time-extended target population showed similar results. Outcome model-based prediction facilitates estimating the average treatment effects of a drug in different target populations when treatment and outcome data are unreliable or unavailable. The predicted effects may inform payers' coverage decisions for patients, especially shortly after a drug's launch when observational data are scarce.

Utilization of direct oral anticoagulants in a Saudi tertiary hospital: a retrospective cohort study

OBJECTIVE

This study aimed to assess the appropriateness of direct oral anticoagulants (DOACs) utilization in a Saudi tertiary hospital.

PATIENTS AND METHODS

Adult inpatients and outpatients diagnosed with atrial fibrillation, deep vein thrombosis, or pulmonary embolism were included in a retrospective cohort study. Patients received at least one month of apixaban, rivaroxaban, or dabigatran. The duration of the study at the Armed Forces Hospital Southern Region in Khamis Mushait, Saudi Arabia, was from January 1, 2019, to December 31, 2021. The study assessed the appropriateness of DOACs dosing, initial and follow-up monitoring, the presence of clinically significant interactions, and treatment duration adherence.

RESULTS

778 patients were included in the analysis (mean age 71.34 ± 15.98 years, equal male and female representation). Rivaroxaban was administered to 40.8% of the patients, while apixaban and dabigatran were administered to 31.02% and 28.18% of the patients, respectively. The most prevalent indication for DOACs was atrial fibrillation (72.84%), followed by deep vein thrombosis and pulmonary embolism (27.16%). The most prevalent category of medication errors was inappropriate maintenance dose (41.7%), followed by inappropriate initial dose (37.97%) and lack of laboratory parameter monitoring (36.42%). 31.5 percent of the study sample lacked baseline renal functions, while 24.5% of patients lacked baseline liver functions. 115 patients (14.8%) had potential clinically significant interactions. Regarding treatment duration, 232 patients (29.8%) were improperly prescribed DOACs based on their indications.

CONCLUSIONS

In a significant proportion of DOAC patients, the prescribed rational DOAC utilization parameters were not implemented. The results of the study provide specific improvement areas and objectives for Anticoagulation stewardship programs.

Real-world data emulating randomized controlled trials of non-vitamin K antagonist oral anticoagulants in patients with venous thromboembolism

BACKGROUND

Emulating randomized controlled trials (RCTs) by real-world evidence (RWE) studies would benefit future clinical and regulatory decision-making by balancing the limitations of RCT. We aimed to evaluate whether the findings from RWE studies can support regulatory decisions derived from RCTs of non-vitamin K antagonist oral anticoagulants (NOACs) in patients with venous thromboembolism (VTE).

METHODS

Five landmark trials (AMPLIFY, RE-COVER II, Hokusai-VTE, EINSTEIN-DVT, and EINSTEIN-PE) of NOACs were emulated using the South Korean nationwide claims database (January 2012 to August 2020). We applied an active comparator and new-user design to include patients who initiated oral anticoagulants within 28 days from their VTE diagnoses. The prespecified eligibility criteria, exposure (each NOAC, such as apixaban, rivaroxaban, dabigatran, and edoxaban), comparator (conventional therapy, defined as subcutaneous heparin followed by warfarin), and the definition of outcomes from RCTs were emulated as closely as possible in each separate emulation cohort. The primary outcome was identical to each trial, which was defined as recurrent VTE or VTE-related death. The safety outcome was major bleeding. Propensity score matching was conducted to balance 69 covariates between the exposure groups. Effect estimates for outcomes were estimated using the Mantel-Haenszel method and Cox proportional hazards model and subsequently compared with the corresponding RCT estimates.

RESULTS

Compared to trial populations, real-world study populations were older (range: 63-69 years [RWE] vs. 54-59 years [RCT]), with more females (55-60.5% vs. 39-48.3%) and had a higher prevalence of active cancer (4.2-15.4% vs. 2.5-9.5%). The emulated estimates for effectiveness outcomes showed superior effectiveness of NOAC (AMPLIFY: relative risk 0.81, 95% confidence interval 0.70-0.94; RE-COVER II: hazard ratio [HR] 0.60, 0.37-0.96; Hokusai-VTE: 0.49, 0.31-0.78; EINSTEIN-DVT: 0.54, 0.33-0.89; EINSTEIN-PE: 0.50, 0.34-0.74), when contrasted with trials that showed non-inferiority. For safety outcomes, all emulations except for AMPLIFY and EINSTEIN-DVT yielded results consistent with their corresponding RCTs.

CONCLUSIONS

This study revealed the feasibility of complementing RCTs with RWE studies by using claims data in patients with VTE. Future studies to consider the different demographic characteristics between RCT and RWE populations are needed.

Comparison of the efficacy and safety between rivaroxaban and dabigatran in the treatment of acute portal vein thrombosis in cirrhosis

BACKGROUND

New oral anticoagulants (NOACs) have been becoming prevalent in recent years and are increasingly used in the treatment of port vein thrombosis. The difference of the efficacy and safety between rivaroxaban and dabigatran remains unclear in the treatment of cirrhotic patients with acute portal vein thrombosis (PVT).

METHODS

This retrospective study included all consecutive cirrhotic patients with acute portal vein thrombosis in our institute from January 2020 to December 2021. The patients received oral anticoagulation with rivaroxaban or dabigatran. The demographic, clinical, and imaging data of patients were collected. The diagnosis of acute PVT was confirmed by imaging examinations. The severity of liver cirrhosis was assessed using Child-Pugh score and Model for End-Stage Liver Disease (MELD) score. Outcomes included recanalization (complete, partial, and persistent occlusion), liver function, bleedings, and survival. The log-rank test was used to compare Kaplan-Meier distributions of time-to-event outcomes. The Cox proportional hazards model was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

A total of 94 patients were included, 52 patients (55%) received rivaroxaban and 42 (45%) with dabigatran. The complete and partial recanalization of PVT was observed in 41 patients. There was no significant difference in complete recanalization, partial recanalization, and persistent occlusion between the two groups. With multivariate analysis, D-dimer (HR 1.165, 95% CI 1.036-1.311, p = 0.011) was independent predictors of complete recanalization. The Child-Pugh score (p = 0.001) was significantly improved in both two groups after anticoagulation, respectively. However, there was no difference between the two groups. The probability of survival was 94%, 95% in the rivaroxaban and dabigatran groups (log-rank p = 0.830). Major bleedings were reported in 3 patients (6%) in rivaroxaban group and 1 patient (2%) in dabigatran group (p = 0.646). Six patients (12%) in rivaroxaban group experienced minor bleeding, and five (12%) from dabigatran group (p = 0.691).

CONCLUSIONS

The efficacy and safety were comparable between rivaroxaban and dabigatran in the treatment of cirrhotic patients with acute portal vein thrombosis. And D-dimer can contribute to the prediction of PVT recanalization in cirrhotic patients.

Development and Validation of the DOAC Score: A Novel Bleeding Risk Prediction Tool for Patients With Atrial Fibrillation on Direct-Acting Oral Anticoagulants

BACKGROUND

Current clinical decision tools for assessing bleeding risk in individuals with atrial fibrillation (AF) have limited performance and were developed for individuals treated with warfarin. This study develops and validates a clinical risk score to personalize estimates of bleeding risk for individuals with atrial fibrillation taking direct-acting oral anticoagulants (DOACs).

METHODS

Among individuals taking dabigatran 150 mg twice per day from 44 countries and 951 centers in this secondary analysis of the RE-LY trial (Randomized Evaluation of Long-Term Anticoagulation Therapy), a risk score was developed to determine the comparative risk for bleeding on the basis of covariates derived in a Cox proportional hazards model. The risk prediction model was internally validated with bootstrapping. The model was then further developed in the GARFIELD-AF registry (Global Anticoagulant Registry in the Field-Atrial Fibrillation), with individuals taking dabigatran, edoxaban, rivaroxaban, and apixaban. To determine generalizability in external cohorts and among individuals on different DOACs, the risk prediction model was validated in the COMBINE-AF (A Collaboration Between Multiple Institutions to Better Investigate Non-Vitamin K Antagonist Oral Anticoagulant Use in Atrial Fibrillation) pooled clinical trial cohort and the Quebec Régie de l'Assurance Maladie du Québec and Med-Echo Administrative Databases (RAMQ) administrative database. The primary outcome was major bleeding. The risk score, termed the DOAC Score, was compared with the HAS-BLED score.

RESULTS

Of the 5684 patients in RE-LY, 386 (6.8%) experienced a major bleeding event, within a median follow-up of 1.74 years. The prediction model had an optimism-corrected C statistic of 0.73 after internal validation with bootstrapping and was well-calibrated based on visual inspection of calibration plots (goodness-of-fit P=0.57). The DOAC Score assigned points for age, creatinine clearance/glomerular filtration rate, underweight status, stroke/transient ischemic attack/embolism history, diabetes, hypertension, antiplatelet use, nonsteroidal anti-inflammatory use, liver disease, and bleeding history, with each additional point scored associated with a 48.7% (95% CI, 38.9%-59.3%; P<0.001) increase in major bleeding in RE-LY. The score had superior performance to the HAS-BLED score in RE-LY (C statistic, 0.73 versus 0.60; P for difference <0.001) and among 12 296 individuals in GARFIELD-AF (C statistic, 0.71 versus 0.66; P for difference = 0.025). The DOAC Score had stronger predictive performance than the HAS-BLED score in both validation cohorts, including 25 586 individuals in COMBINE-AF (C statistic, 0.67 versus 0.63; P for difference <0.001) and 11 945 individuals in RAMQ (C statistic, 0.65 versus 0.58; P for difference <0.001).

CONCLUSIONS

In individuals with atrial fibrillation potentially eligible for DOAC therapy, the DOAC Score can help stratify patients on the basis of expected bleeding risk.

Studies on Atrial Fibrillation and Venous Thromboembolism in the Past 20 Years: A Bibliometric Analysis Via CiteSpace and VOSviewer

The conjunction of atrial fibrillation (AF) and venous thromboembolism (VTE) is common in clinical practice. Over the last 2 decades, a significant number of articles (2500) have been published about AF and VTE. To effectively analyze and present these vast amounts of information, this study uses bibliometric research methods to categorize and consolidate these publications. The number of publications has increased yearly, especially since 2012. The United States was the most prolific country, with 1054 studies published. The most productive institution was McMaster University. Gregory Y.H. Lip was the most prolific author. The keyword analysis identified that the research focuses from 2003 to 2014 were factor Xa inhibitor, dabigatran etexilate, direct thrombin inhibitor, double-blind, deep vein thrombosis, molecular weight heparin, stroke prevention, etc. From 2015 to 2016, research mainly focused on venous thromboembolism, antithrombotic therapy, anticoagulant, warfarin, atrial fibrillation, stroke, and pulmonary embolism. Studies during 2017 to 2022 focused on apixaban, direct oral anticoagulant, rivaroxaban, dabigatran, hemorrhage, edoxaban, medicine efficacy and safety, risk factors, clinical management, and vitamin K antagonists. Since 2018, novel oral anticoagulants have been the most commonly used keywords. On the whole, most studies of AF and VTE focus on pathogenesis and therapeutic drugs. The causal relationship between AF and VTE, the effectiveness and safety of novel oral anticoagulants in the treatments, the anticoagulant regimen of AF and VTE co-disease, and the treatment regimen for vulnerable populations such as the elderly or obese people were the focus of current research and will continue to be the central point of future research.

Comparison of bleeding and ischemic events with apixaban vs. rivaroxaban in triple antithrombotic therapy regimens

OBJECTIVE

To compare the risk of readmissions for major bleeding within one year between apixaban and rivaroxaban as a component of triple antithrombotic therapy.

METHODS

This study was a multicenter, retrospective cohort study conducted at two academic medical centers in the Western New York and New York City region between July 1, 2011 and September 25, 2019. Adult patients were included if they were diagnosed with atrial fibrillation or venous thromboembolism and discharged on new triple antithrombotic therapy. The primary outcome compared the rates of 1-year readmission for major bleeding between apixaban and rivaroxaban groups. Secondary outcomes included rate of ischemic outcomes. Time to event analysis was determined with a Kaplan-Meier plot and Cox proportional hazard ratios (HR).

RESULTS

A total of 378 patients were included in the study, 212 in the apixaban group and 166 in the rivaroxaban group. Within 1 year, readmission for major bleeding events occurred in six (2.8%) patients in the apixaban group and four (2.4%) patients in the rivaroxaban group ( P  = 1.000). After adjustment, the major bleeding event rate was not statistically significantly different between apixaban and rivaroxaban [adjusted hazard ratio (aHR) 0.68, 95% confidence interval (CI) 0.12-3.77; P  = 0.6624]. Higher albumin levels were identified to be protective against major bleeding related readmission events (aHR 0.18, 95% CI 0.05-0.63; P  = 0.0072). The ischemic outcome occurred in seven (3.3%) patients in the apixaban group and three (1.8%) in the rivaroxaban group ( P  = 0.7368).

CONCLUSION

Use of apixaban or rivaroxaban in a triple antithrombotic regimen was not associated with bleeding or ischemic outcomes.

Clinical Relevance of Preclinical and Clinical Studies of Four-Factor Prothrombin Complex Concentrate for Treatment of Bleeding Related to Direct Oral Anticoagulants

Direct oral anticoagulants (DOACs) are widely used for the prevention and treatment of venous thromboembolism and stroke. When emergency reversal of DOAC-related anticoagulation is required, specific DOAC reversal agents are recommended, including idarucizumab for dabigatran reversal and andexanet alfa for apixaban and rivaroxaban reversal. However, specific reversal agents are not always available, andexanet alfa has not been approved for urgent surgery, and clinicians need to know the patient's anticoagulant medication before administering these treatments. Four-factor prothrombin complex concentrates (4F-PCCs) are recognized as nonspecific, alternative hemostatic agents for treatment of DOAC-related bleeding. Evidence from preclinical and clinical studies shows that they may reduce the anticoagulant effects of DOACs and may help control DOAC-related bleeding. However, randomized controlled trials are lacking, and most data are from retrospective or single-arm prospective studies in bleeding associated with activated factor X inhibitors. There are no clinical data showing the efficacy of 4F-PCC for the treatment of bleeding in dabigatran-treated patients. This review focuses on the current evidence of 4F-PCC use in controlling bleeding associated with DOACs and provides an expert opinion on the relevance of these data for clinical practice. The current treatment landscape, unmet needs, and future directions are also discussed.

DOAC Dosing Discordance Using Different Estimates of Kidney Function and Outcomes

Direct oral anticoagulants (DOACs) are indicated for the prevention of stroke in nonvalvular atrial fibrillation. Although Food and Drug Administration labeling for DOACs uses estimated creatinine clearance according to the Cockcroft-Gault (C-G) equation, estimated glomerular filtration rate according to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation is often reported. The objectives of this study were to evaluate DOAC dosing discordance and to determine whether discordance based on various estimates of kidney function is associated with bleeding or thromboembolism. The study was an institutional review board approved retrospective analysis of patients at UPMC Presbyterian Hospital from January 1, 2010, to December 12, 2016. Data were obtained through electronic medical records. Adults who received a medication charge for rivaroxaban or dabigatran, had a diagnosis code for atrial fibrillation, and had a serum creatinine within 3 days of DOAC initiation were included. Doses were considered discordant if the calculated dose based on CKD-EPI did not match the patient's dose during index admission, if dosed correctly using C-G. Association of discordance with dabigatran, rivaroxaban, and clinical outcomes was determined using odds ratios and 95% confidence intervals. Rivaroxaban discordance was present among 49 of the 644 (8%) patients who were dosed correctly with C-G. Dabigatran discordance was present among 17 of the 590 (3%) patients who were dosed correctly. Discordance with rivaroxaban was found to increase the risk of thromboembolism when using CKD-EPI (odds ratio, 2.83; 95% CI, 1.02-7.79, P = .045) versus C-G. Our findings emphasize the need to dose DOACs, specifically rivaroxaban, appropriately in patients with nonvalvular atrial fibrillation.

Plasma Drug Values of DOACs in Patients Presenting with Gastrointestinal Bleeding: A Prospective Observational Study

Background and Objectives: Anticoagulants are a well-known risk factor for gastrointestinal bleeding (GIB). In recent years, direct oral anticoagulants (DOACs) have taken a leading role in the treatment and prevention of thromboembolic incidents. The aim of this study was to investigate the prevalence of DOAC-treated patients with GIB whose plasma drug concentrations exceeded the cut-off values reported in the literature and to evaluate their clinical characteristics. Materials and Methods: Patients who were admitted to the Intensive Care Unit in the period 2/2020-3/2022 due to GIB were prospectively included in the study and classified into three groups according to the prescribed type of DOAC (apixaban, rivaroxaban, and dabigatran). For all participants, it was determined if the measured plasma drug levels exceeded the maximum serum concentration (Cmax) or trough serum concentration (Ctrough) obtained from the available data. A comparison of clinical parameters between the patients with and without excess drug values was performed. Results: There were 90 patients (54.4% men) included in the study, of whom 27 were treated with dabigatran, 24 with apixaban, and 39 with rivaroxaban. According to Cmax, there were 34 (37.8%), and according to Ctrough, there were 28 (31.1%) patients with excess plasma drug values. A statistically significant difference regarding excess plasma drug values was demonstrated between DOACs according to both Cmax (p = 0.048) and Ctrough (p < 0.001), with the highest rate in the group treated with dabigatran (55.6% for Cmax and 59.3% for Ctrough). Multivariate logistic regression showed that age (OR 1.177, p = 0.049) is a significant positive and glomerular filtration rate (OR 0.909, p = 0.016) is a negative predictive factor for excess plasma drug values. A total of six (6.7%) patients had fatal outcomes. Conclusions: Plasma drug concentrations exceed cut-off values reported in the literature in more than one-third of patients with GIB taking DOAC, with the highest rate in the dabigatran group. Clinicians should be more judicious when prescribing dabigatran to the elderly and patients with renal failure. In these patients, dose adjustment, plasma drug monitoring, or substitution with other, more appropriate DOACs should be considered.

Idarucizumab for dabigatran reversal: A systematic review and meta-analysis of indications and outcomes

BACKGROUND

Idarucizumab has been approved to reverse the anticoagulant effect of dabigatran. However, there is little knowledge of the effectiveness and safety of idarucizumab in daily practice.

AIMS

This systematic review and meta-analysis aims to evaluate the use, effectiveness and outcomes of idarucizumab.

METHODS

A systematic literature search was performed up to September 8th 2022. Original studies including patients prescribed idarucizumab, evaluating prescription indications, prescription appropriateness, haemostatic efficacy and/or the occurrence of adverse events were eligible. Case-reports and studies performed in patients ≤18 years or in healthy volunteers were excluded. Study selection and data extraction were performed by two independent reviewers. Pooled estimates were calculated using the random-effects model, after Freeman-Tukey double-arcsine transformation.

RESULTS

Thirty studies comprising 3602 patients were included. Idarucizumab was prescribed for bleeding (63.1 %, 95%CI 57.0 %-69.0 %), invasive procedures (30.5 %, 95%CI: 24.1 %-37.2 %), to enable thrombolysis (range: 2.0 %-27.3 %), dabigatran intoxication without bleeding (range: 3.6 %-7.0 %) or unspecified reasons (range: 0.4 %-18.8 %). Overall, 2.8 % (95%CI 0.5 %-6.2 %) of prescription indications were reported to be inappropriate upon post-hoc evaluation. Hemostatic effectiveness was achieved in 77.7 % (95%CI 66.7 %-87.2 %) and peri-procedural haemostasis was normal in 98.5 % (95%CI 86.6 %-100 %) of patients. The pooled incidences of all-cause mortality and thromboembolic events at any follow-up duration were 13.6 % (95%CI 9.6 %-17.9 %) and 2.0 % (95%CI 0.8 %-3.4 %), respectively.

CONCLUSION

Idarucizumab was mainly prescribed in the setting of bleeding. The reported hemostatic effectiveness was good, especially perioperatively, and the incidence of thromboembolic events was low. Patients with dabigatran-associated bleeding or requiring an urgent procedure nonetheless face a high mortality risk.

Direct oral anticoagulants and their antagonists in perioperative practice

PURPOSE OF REVIEW

Review management strategies for patients receiving nonvitamin K direct-acting oral anticoagulants (DOACs).

RECENT FINDINGS

Updated clinical trials and guidelines continue to further define optimal management for patients on DOACs requiring emergency surgery or procedural interventions. In addition, specific bleeding management strategies that include either specific or nonspecific antagonists are becoming available.

SUMMARY

Most currently used DOACs are factor Xa inhibitors and should be stopped for 24-48 h for elective surgical procedures in patients at risk for bleeding and potentially longer for dabigatran, depending on renal function. Idarucizumab, a specific dabigatran reversal agent, has been studied in surgical patients and is currently approved for use. For Xa inhibitors apixaban and rivaroxaban, although andexanet alfa is approved for medical bleeds, it is not approved for surgical patients, has a short duration of effect, and costs $12 500 per gram. When managing DOAC-treated patients requiring emergency surgery, when stopping the DOAC and delaying surgery is not feasible, standard approaches should include hemostatic, hemodynamic, and transfusional support. Due to higher risk associated with therapeutic agents used to manage DOAC-related bleeding, increasing data supports the potential off-label use of prothrombin complex concentrate (PCC).

Non-major bleeding risk of direct oral anticoagulants versus vitamin K antagonists for stroke prevention with atrial fibrillation: a systematic review and network meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs) are associated with bleeding. Patients often stop taking DOACs due to non-major bleeding, which may lead to stroke recurrence. We aimed to determine the risk of non-major bleeding using different DOACs to prevent strokes in atrial fibrillation (AF).

METHODS

A systematic search of four databases (PubMed, EMBASE, Web of Science, and Cochrane Library) was performed to identify randomized controlled trials (RCTs) reporting non-major bleeding events in patients taking DOACs or vitamin K antagonists (VKAs). In this frequency-based network meta-analysis, odds ratios and 95% confidence intervals were used for reporting. Based on the surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Nineteen randomized controlled trials (RCTs) (involving 85,826 patients) were included. For clinically relevant non-major bleeding, the risk for bleeding was lowest for apixaban (SUCRA, 93.9), followed by that for VKAs (SUCRA, 47.7), dabigatran (SUCRA, 40.3), rivaroxaban (SUCRA, 35.9), and edoxaban (SUCRA, 32.2). The minor bleeding safety of DOACs was ranked from highest to lowest as follows: apixaban (SUCRA, 78.1), edoxaban (SUCRA, 69.4), dabigatran (SUCRA, 48.8), and VKAs (SUCRA, 3.7).

CONCLUSIONS

Based on current evidence, for stroke prevention in patients with AF, the safest DOAC is apixaban in terms of non-major bleeding. This suggests that apixaban may have a lower risk of non-major bleeding than other anticoagulants and may help provide some clinical reference for choosing a more appropriate drug for the patient.

ORal anticoaGulants in diAbetic and Nondiabetic patients with nOn-valvular atrial fibrillatioN (ORGANON)

BACKGROUND

Diabetes represents a pro-thrombotic condition.

OBJECTIVES

The primary objective was to evaluate the effects of Vitamin K Antagonist (VKA) compared to direct oral anticoagulants (DOACs) in diabetic and nondiabetic patients with non-valvular atrial fibrillation, newly diagnosed. The secondary objective was to evaluate the effects on the risk of bleeding.

METHODS

We enrolled 300 patients with newly diagnosed atrial fibrillation. One hundred and sixteen patients were taking warfarin, 31 acenocumarol, 22 dabigatran, 80 rivaroxaban, 34 apixaban, and 17 edoxaban. We evaluated: anthropometric parameters, glycated hemoglobin (HbA1c), fasting and post-prandial glucose (FPG, and PPG), lipid profile, Lp(a), small and dense low-density lipoprotein (SD-LDL), oxidized LDL (Ox-LDL), I-troponin (I-Tn), creatinine, transaminases, iron, red blood cells (RBC); hemoglobin (Hb), platelets (PLT), fibrinogen, D-dimer, anti-thrombin III, C-reactive protein (Hs-CRP), Metalloproteinases-2 (MMP-2), Metalloproteinases-9 (MMP-9), and incidence of bleeding.

RESULTS

We did not record any differences among nondiabetic patients between VKA and DOACs. However, when we considered diabetic patients, we found a slight, but significant improvement of triglycerides and SD-LDL. As regards incidence of bleeding, minor bleeding was more frequent in VKA diabetic group compared to DOACs diabetic group; furthermore, the incidence of major bleeding was higher with VKA in nondiabetic and diabetic group, compared to patients with DOACs. Among DOACs, we recorded a higher incidence of bleeding (minor and major) with dabigatran compared to rivaroxaban, apixaban and edoxaban in nondiabetic and diabetic patients.

CONCLUSION

DOACs seem to be metabolically favourable in diabetic patients. Regarding incidence of bleeding, DOACs with the exception of dabigatran, seem better than VKA in diabetic patients.

Effectiveness and safety of Dabigatran 110 mg versus 150 mg for Stroke Prevention in Patients with Atrial Fibrillation at High Bleeding Risk

PURPOSE

The effectiveness and tolerability of a reduced dose (110 mg) of dabigatran versus the standard dose (150 mg) were evaluated in subgroups of patients with atrial fibrillation (AF) at high bleeding risk.

METHODS

Eligible patients were adults with AF and a creatinine clearance rate ≥30 mL/min who were initiated on treatment with dabigatran (index) between 2016 and 2018. High-bleeding-risk subgroups were identified: (1) age ≥80 years; (2) moderate renal impairment (creatinine clearance rate 30-<50 mL/min); and (3) recent bleeding or a HAS-BLED score of ≥3. Fine-Gray subdistribution hazard regression models with inverse probability of treatment weights were used to investigate associations between dabigatran dose and three outcomes: stroke or systemic embolism, major bleeding requiring hospitalization, and all-cause mortality.

FINDINGS

Among 7858 patients with AF and a high bleeding risk (age ≥80 years, 3472; moderate renal impairment, 1574; recent bleeding or HAS-BLED score ≥3, 2812), 32.3% received reduced-dose dabigatran. Compared with the standard dose, use of the reduced dose of dabigatran was not associated with an increased risk for stroke or systemic embolism but was associated with a lower risk for major bleeding (HR = 0.65; 95% CI, 0.44-0.95) and all-cause mortality (HR = 0.78; 95% CI, 0.65-0.92) in patients aged ≥80 years. The use of reduced-dose dabigatran was associated with a lower risk for major bleeding (HR = 0.54; 95% CI, 0.30-0.95) and all-cause mortality among patients with moderate renal impairment (HR = 0.53; 95% CI, 0.40-0.71).

IMPLICATIONS

Lower risks for bleed and mortality associated with reduced- versus standard-dose dabigatran in patients with AF and a high bleeding risk suggest a better dosing strategy.

Risk for Bleeding-Related Hospitalizations During Use of Amiodarone With Apixaban or Rivaroxaban in Patients With Atrial Fibrillation : A Retrospective Cohort Study

BACKGROUND

Amiodarone, the most effective antiarrhythmic drug in atrial fibrillation, inhibits apixaban and rivaroxaban elimination, thus possibly increasing anticoagulant-related risk for bleeding.

OBJECTIVE

For patients receiving apixaban or rivaroxaban, to compare risk for bleeding-related hospitalizations during treatment with amiodarone versus flecainide or sotalol, antiarrhythmic drugs that do not inhibit these anticoagulants' elimination.

DESIGN

Retrospective cohort study.

SETTING

U.S. Medicare beneficiaries aged 65 years or older.

PATIENTS

Patients with atrial fibrillation began anticoagulant use between 1 January 2012 and 30 November 2018 and subsequently initiated treatment with study antiarrhythmic drugs.

MEASUREMENTS

Time to event for bleeding-related hospitalizations (primary outcome) and ischemic stroke, systemic embolism, and death with or without recent (past 30 days) evidence of bleeding (secondary outcomes), adjusted with propensity score overlap weighting.

RESULTS

There were 91 590 patients (mean age, 76.3 years; 52.5% female) initiating use of study anticoagulants and antiarrhythmic drugs, 54 977 with amiodarone and 36 613 with flecainide or sotalol. Risk for bleeding-related hospitalizations increased with amiodarone use (rate difference [RD], 17.5 events [95% CI, 12.0 to 23.0 events] per 1000 person-years; hazard ratio [HR], 1.44 [CI, 1.27 to 1.63]). Incidence of ischemic stroke or systemic embolism did not increase (RD, -2.1 events [CI, -4.7 to 0.4 events] per 1000 person-years; HR, 0.80 [CI, 0.62 to 1.03]). The risk for death with recent evidence of bleeding (RD, 9.1 events [CI, 5.8 to 12.3 events] per 1000 person-years; HR, 1.66 [CI, 1.35 to 2.03]) was greater than that for other deaths (RD, 5.6 events [CI, 0.5 to 10.6 events] per 1000 person-years; HR, 1.15 [CI, 1.00 to 1.31]) (HR comparison: P = 0.003). The increased incidence of bleeding-related hospitalizations for rivaroxaban (RD, 28.0 events [CI, 18.4 to 37.6 events] per 1000 person-years) was greater than that for apixaban (RD, 9.1 events [CI, 2.8 to 15.3 events] per 1000 person-years) (P = 0.001).

LIMITATION

Possible residual confounding.

CONCLUSION

In this retrospective cohort study, patients aged 65 years or older with atrial fibrillation treated with amiodarone during apixaban or rivaroxaban use had greater risk for bleeding-related hospitalizations than those treated with flecainide or sotalol.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately one in 1000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors, which have characteristics that may be favourable compared to conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or dose adjustment and few known drug interactions. DOACs are now commonly being used for treating DVT: recent guidelines recommended DOACs over conventional anticoagulants for both DVT and PE treatment. This Cochrane Review was first published in 2015. It was the first systematic review to measure the effectiveness and safety of these drugs in the treatment of DVT. This is an update of the 2015 review.  OBJECTIVES: To assess the effectiveness and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of DVT.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 1 March 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a DVT, confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with conventional anticoagulation or compared with each other for the treatment of DVT.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were recurrent venous thromboembolism (VTE), recurrent DVT and PE. Secondary outcomes included all-cause mortality, major bleeding, post-thrombotic syndrome (PTS) and quality of life (QoL). We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified 10 new studies with 2950 participants for this update. In total, we included 21 RCTs involving 30,895 participants. Three studies investigated oral DTIs (two dabigatran and one ximelagatran), 17 investigated oral factor Xa inhibitors (eight rivaroxaban, five apixaban and four edoxaban) and one three-arm trial investigated both a DTI (dabigatran) and factor Xa inhibitor (rivaroxaban). Overall, the studies were of good methodological quality. Meta-analysis comparing DTIs to conventional anticoagulation showed no clear difference in the rate of recurrent VTE (odds ratio (OR) 1.17, 95% confidence interval (CI) 0.83 to 1.65; 3 studies, 5994 participants; moderate-certainty evidence), recurrent DVT (OR 1.11, 95% CI 0.74 to 1.66; 3 studies, 5994 participants; moderate-certainty evidence), fatal PE (OR 1.32, 95% CI 0.29 to 6.02; 3 studies, 5994 participants; moderate-certainty evidence), non-fatal PE (OR 1.29, 95% CI 0.64 to 2.59; 3 studies, 5994 participants; moderate-certainty evidence) or all-cause mortality (OR 0.66, 95% CI 0.41 to 1.08; 1 study, 2489 participants; moderate-certainty evidence). DTIs reduced the rate of major bleeding (OR 0.58, 95% CI 0.38 to 0.89; 3 studies, 5994 participants; high-certainty evidence).   For oral factor Xa inhibitors compared with conventional anticoagulation, meta-analysis demonstrated no clear difference in recurrent VTE (OR 0.85, 95% CI 0.71 to 1.01; 13 studies, 17,505 participants; moderate-certainty evidence), recurrent DVT (OR 0.70, 95% CI 0.49 to 1.01; 9 studies, 16,439 participants; moderate-certainty evidence), fatal PE (OR 1.18, 95% CI 0.69 to 2.02; 6 studies, 15,082 participants; moderate-certainty evidence), non-fatal PE (OR 0.93, 95% CI 0.68 to 1.27; 7 studies, 15,166 participants; moderate-certainty evidence) or all-cause mortality (OR 0.87, 95% CI 0.67 to 1.14; 9 studies, 10,770 participants; moderate-certainty evidence). Meta-analysis showed a reduced rate of major bleeding with oral factor Xa inhibitors compared with conventional anticoagulation (OR 0.63, 95% CI 0.45 to 0.89; 17 studies, 18,066 participants; high-certainty evidence).  AUTHORS' CONCLUSIONS: The current review suggests that DOACs may be superior to conventional therapy in terms of safety (major bleeding), and are probably equivalent in terms of efficacy. There is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent VTE, recurrent DVT, pulmonary embolism and all-cause mortality. DOACs reduced the rate of major bleeding compared to conventional anticoagulation. The certainty of evidence was moderate or high.

Severe Bleeding Risk of Direct Oral Anticoagulants Versus Vitamin K Antagonists for Stroke Prevention and Treatment in Patients with Atrial Fibrillation: A Systematic Review and Network Meta-Analysis

PURPOSE

We aimed to determine the safety of direct oral anticoagulants (DOACs) for stroke prevention and treatment in patients with atrial fibrillation (AF).

METHODS

A systematic search of four databases (PubMed, EMBASE, Web of Science, and Cochrane Library) was performed to identify randomized controlled trials (RCTs) reporting severe bleeding events in patients taking DOACs or vitamin K antagonists (VKAs). In this frequency-based network meta-analysis, odds ratios and 95% confidence intervals were used for reporting. Based on the surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Twenty-three RCTs met the inclusion criteria, and a total of 87,616 patients were enrolled. The bleeding safety of DOACs for stroke prevention and treatment in patients with AF was ranked from highest to lowest as follows: fatal bleeding: edoxaban (SUCRA,80.2), rivaroxaban (SUCRA,68.3), apixaban (SUCRA,48.5), dabigatran (SUCRA,40.0), VKAs (SUCRA,12.9); major bleeding: dabigatran (SUCRA,74.0), apixaban (SUCRA,71.5), edoxaban (SUCRA,66.5), rivaroxaban (SUCRA,22.7), VKAs (SUCRA,15.4); gastrointestinal bleeding: apixaban (SUCRA,55.9), VKAs (SUCRA,53.7), edoxaban (SUCRA,50.5), rivaroxaban (SUCRA,50.4), dabigatran (SUCRA,39.5); intracranial hemorrhage: dabigatran (SUCRA,84.6), edoxaban (SUCRA,74.1), apixaban (SUCRA,65.8), rivaroxaban (SUCRA,24.4), VKAs (SUCRA,1.1).

CONCLUSION

Based on current evidence, for stroke prevention and treatment in patients with AF, the most safe DOAC is edoxaban in terms of fatal bleeding; dabigatran in terms of major bleeding and intracranial hemorrhage and apixaban in terms of gastrointestinal bleeding. However, given the nature of indirect comparisons, more high-quality evidence from head-to-head comparisons is still needed to confirm them.

Effect of tramadol and DOACs with special attention to dabigatran on concomitant use, on the risk of mayor bleeding using BIFAP database in Spain

BACKGROUND

Tramadol, a weak opioid, inhibits the reuptake of serotonin, a key feature on vascular homeostasis. A suspected interaction exists between dabigatran and tramadol, which might trigger an excess on risk of bleeding however, there is a gap in knowledge on this topic.

PURPOSE

To estimate the effects of tramadol, dabigatran and concomitant use on the risk of hospitalized major bleeds (Gastrointestinal bleeding and intra-extracranial bleeds).

METHODS

Among a validated established cohort of new users of oral anticoagulants for non-valvular atrial fibrillation (NVAF) aged 18 years or older, we identified all hospitalized bleed episodes (GIB and extra/intracranial bleeds) within 2008-2015. A nested case-control analysis was conducted using conditional logistic regression. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were calculated for dabigatran, tramadol, and concomitant use. Several sensitivity analyses were carried out.

RESULTS

aORs (95%CIs) for current use of only dabigatran, only tramadol and concomitant users were 1.73 (1.37-2.18) and 1.38 (1.13-1.67) and 2.04 (0.74-5.67) compared with non-users of both drugs (>365 days). aORs for current continuers and non-continuer users of dabigatran were 1.36 (1.00-1.86) and 2.19 (1.61-2.98), respectively. For the latter, non-continuer users with a short duration of dabigatran cumulated the highest risk (3.36 [1.88-5.99]). There also was an increased risk with concomitant use of tramadol and rivaroxaban (2.24 [1.19-4.21]), or antagonist of vitamin K (1.30 [1.00-1.69]).

CONCLUSION

There was a trend towards and increased risk of excess bleeds when using concomitantly with dabigatran. The effect decreases with a narrower definition of current use.

Analysis of the clinical characteristics of dabigatran-induced oesophagitis

OBJECTIVES

Dabigatran-induced oesophagitis has emerged in recent years. However, the incidence and clinical characteristics of patients with dabigatran-induced oesophagitis have not yet been clarified. The aim of this study was to examine the clinical characteristics of the disease.

METHODS

A retrospective analysis was undertaken of the literature on dabigatran-induced oesophagitis in Chinese and English from 2008 onwards.

RESULTS

There were 20 men (74.07%) and seven women (25.93%) in the study; their median age was 75 years (range 37-90). The main clinical symptoms were dysphagia (42.31%), odynophagia (26.92%), retrosternal pain (23.08%) and heartburn (23.08%). Endoscopy mainly showed sloughing mucosal casts (14 cases, 56%), ulcers (8 cases, 32%) and erosion (6 cases, 24%). The main injury sites were the mid to lower oesophagus (32%) and the mid oesophagus (32%). Withdrawal of dabigatran or giving the correct medication regimen resulted in rapid recovery of clinical symptoms from 1 day in some patients and up to 4 weeks, and mucosal recovery (2-5 weeks) in a median time of 3 weeks (range 0.29-48) in all patients.

CONCLUSIONS

Oesophagitis is a rare complication of dabigatran with a good prognosis. Patients should be given proper medication instructions to prevent the occurrence of dabigatran-induced oesophagitis.

DOAC-associated bleeding, hemostatic strategies, and thrombin generation assays - a review of the literature

Direct oral anticoagulants (DOACs) account for most oral anticoagulant use. DOAC-associated bleeding events are commonly encountered in clinical practice and are associated with substantial morbidity and mortality. Both specific reversal agents and nonspecific hemostatic therapies, such as prothrombin complex concentrates, are used in the management of DOAC-associated bleeding. Measuring hemostatic efficacy and demonstrating a clinical impact from these therapies among studies of bleeding patients is challenging. Thrombin generation assays provide information on the total hemostatic potential of plasma, and have emerged as a promising modality to both measure the impact of DOACs on coagulation and to evaluate the effects of hemostatic therapies among patients with DOAC-associated bleeding. The mechanisms by which nonspecific hemostatic agents impact coagulation and thrombin generation in the context of DOAC therapy are unclear. As a result, we undertook a review of the literature using a systematic search strategy with the goal of summarizing the effects of DOACs on thrombin generation and the effects of both specific reversal agents and nonspecific hemostatic therapies on DOAC-altered thrombin generation parameters. We sought to identify clinical studies focusing on whether altered thrombin generation is associated with clinical bleeding and whether correction of altered thrombin generation parameters predicts improvements in clinical hemostasis. Lastly, we sought to outline future directions for the application of thrombin generation assays toward anticoagulation therapies and the question of anticoagulation reversal.

Comparative Effectiveness and Safety of Oral Anticoagulants by Dementia Status in Older Patients With Atrial Fibrillation

Importance

The development of an optimal stroke prevention strategy, including the use of oral anticoagulant (OAC) therapy, is particularly important for patients with atrial fibrillation (AF) who are living with dementia, a condition that increases the risk of adverse outcomes. However, data on the role of dementia in the safety and effectiveness of OACs are limited.

Objective

To assess the comparative safety and effectiveness of specific OACs by dementia status among older patients with AF.

Design, Setting, and Participants

This retrospective comparative effectiveness study used 1:1 propensity score matching among 1 160 462 patients 65 years or older with AF. Data were obtained from the Optum Clinformatics Data Mart (January 1, 2013, to June 30, 2021), IBM MarketScan Research Database (January 1, 2013, to December 31, 2020), and Medicare claims databases maintained by the Centers for Medicare & Medicaid Services (inpatient, outpatient, and pharmacy; January 1, 2013, to December 31, 2017). Data analysis was performed from September 1, 2021, to May 24, 2022.

Exposures

Apixaban, dabigatran, rivaroxaban, or warfarin.

Main Outcomes and Measures

Composite end point of ischemic stroke or major bleeding events over the 6-month period after OAC initiation, pooled across databases using random-effects meta-analyses.

Results

Among 1 160 462 patients with AF, the mean (SD) age was 77.4 (7.2) years; 50.2% were male, 80.5% were White, and 7.9% had dementia. Three comparative new-user cohorts were established: warfarin vs apixaban (501 990 patients; mean [SD] age, 78.1 [7.4] years; 50.2% female), dabigatran vs apixaban (126 718 patients; mean [SD] age, 76.5 [7.1] years; 52.0% male), and rivaroxaban vs apixaban (531 754 patients; mean [SD] age, 76.9 [7.2] years; 50.2% male). Among patients with dementia, compared with apixaban users, a higher rate of the composite end point was observed in warfarin users (95.7 events per 1000 person-years [PYs] vs 64.2 events per 1000 PYs; adjusted hazard ratio [aHR], 1.5; 95% CI, 1.3-1.7), dabigatran users (84.5 events per 1000 PYs vs 54.9 events per 1000 PYs; aHR, 1.5; 95% CI, 1.2-2.0), and rivaroxaban users (87.4 events per 1000 PYs vs 68.5 events per 1000 PYs; aHR, 1.3; 95% CI, 1.1-1.5). In all 3 comparisons, the magnitude of the benefits associated with apixaban was similar regardless of dementia diagnosis on the HR scale but differed substantially on the rate difference (RD) scale. The adjusted RD of the composite outcome per 1000 PYs for warfarin vs apixaban users was 29.8 (95% CI, 18.4-41.1) events in patients with dementia vs 16.0 (95% CI, 13.6-18.4) events in patients without dementia. The corresponding adjusted RD estimates of the composite outcome were 29.6 (95% CI, 11.6-47.6) events per 1000 PYs in patients with dementia vs 5.8 (95% CI, 1.1-10.4) events per 1000 PYs in patients without dementia for dabigatran vs apixaban users and 20.5 (95% CI, 9.9-31.1) events per 1000 PYs in patients with dementia vs 15.9 (95% CI, 11.4-20.3) events per 1000 PYs in patients without dementia for rivaroxaban vs apixaban users. The pattern was more distinct for major bleeding than for ischemic stroke.

Conclusions and Relevance

In this comparative effectiveness study, apixaban was associated with lower rates of major bleeding and ischemic stroke compared with other OACs. The increased absolute risks associated with other OACs compared with apixaban were greater among patients with dementia than those without dementia, particularly for major bleeding. These findings support the use of apixaban for anticoagulation therapy in patients living with dementia who have AF.

Warfarin Is Associated With Higher Rates of Upper But Not Lower Gastrointestinal Bleeding Compared with Direct Oral Anticoagulants: A Population-Based Propensity-Weighted Cohort Study

BACKGROUND AND AIMS

While overall gastrointestinal bleeding (GIB) rates have been extensively compared between warfarin and direct oral anticoagulants (DOACs), it is still unclear whether upper and lower GIB rates differ between these types of drugs. This study aimed to compare upper and lower GIB rates between warfarin and DOACs in a nationwide cohort.

METHODS

Data on all patients in Iceland who received a prescription for oral anticoagulation from 2014 to 2019 were collected and their personal identification numbers linked to the electronic medical record system of the National University Hospital of Iceland and the 4 regional hospitals in Iceland. Inverse probability weighting was used to yield balanced study groups and rates of overall, major, upper, and lower GIB were compared using Cox regression. All GIB events were manually confirmed by chart review.

RESULTS

Warfarin was associated with higher rates of upper GIB (1.7 events per 100 person-years vs 0.8 events per 100 person-years; hazard ratio [HR], 2.12; 95% confidence interval [CI], 1.26-3.59) but similar rates of lower GIB compared with DOACs. Specifically, warfarin was associated with higher rates of upper GIB compared with apixaban (HR, 2.63; 95% CI, 1.35-5.13), dabigatran (5.47; 95% CI, 1.87-16.05), and rivaroxaban (HR, 1.74; 95% CI, 1.00-3.05). Warfarin was associated with higher rates of major GIB compared with apixaban (2.3 events per 100 person-years vs 1.5 events per 100 person-years; HR, 1.79; 95% CI, 1.06-3.05), but otherwise overall and major GIB rates were similar in warfarin and DOAC users.

CONCLUSIONS

Warfarin was associated with higher rates of upper but not overall or lower GIB compared with DOACs. Warfarin was associated with higher rates of major GIB compared with apixaban.

Integrated Machine Learning Decision Tree Model for Risk Evaluation in Patients with Non-Valvular Atrial Fibrillation When Taking Different Doses of Dabigatran

The new generation of nonvitamin K antagonists are broadly applied for stroke prevention due to their notable efficacy and safety. Our study aimed to develop a suggestive utilization of dabigatran through an integrated machine learning (ML) decision-tree model. Participants taking different doses of dabigatran in the Randomized Evaluation of Long-Term Anticoagulant Therapy trial were included in our analysis and defined as the 110 mg and 150 mg groups. The proposed scheme integrated ML methods, namely naive Bayes, random forest (RF), classification and regression tree (CART), and extreme gradient boosting (XGBoost), which were used to identify the essential variables for predicting vascular events in the 110 mg group and bleeding in the 150 mg group. RF (0.764 for 110 mg; 0.747 for 150 mg) and XGBoost (0.708 for 110 mg; 0.761 for 150 mg) had better area under the receiver operating characteristic curve (AUC) values than logistic regression (benchmark model; 0.683 for 110 mg; 0.739 for 150 mg). We then selected the top ten important variables as internal nodes of the CART decision tree. The two best CART models with ten important variables output tree-shaped rules for predicting vascular events in the 110 mg group and bleeding in the 150 mg group. Our model can be used to provide more visualized and interpretable suggestive rules to clinicians managing NVAF patients who are taking dabigatran.

Protocolized management of bleeding in hospitals in The Netherlands in patients treated with direct oral anticoagulants

OBJECTIVE

To investigate and describe the protocolized treatment of DOAC-related bleeds in all Dutch hospitals.

METHODS

From August to December 2020 a nationwide survey among all 70 hospitals in the Netherlands was conducted on their protocols for management of bleeding in patients treated with direct oral anticoagulants (DOACs, i.e. apixaban, edoxaban, rivaroxaban and dabigatran). The protocols were assessed the following characteristics: bleeding definitions (mild, moderate and severe bleed), diagnostic parameters (hemoglobin [Hb], loss of blood, surgical procedure needed, etc), first and second choice of treatment, effectiveness criteria and the level of evidence/references upon which protocols were based.

RESULTS

All 70 hospitals responded (100%). We received 69 protocols in total, 6 of which were identical because hospitals worked together. In 35 (50%) of the protocols a definition of minor, moderate or severe bleeds was described. Diagnostic parameters for bleeds were present in 2%, 41% and 47% of protocols for a mild, moderate and severe bleed. While the first choice treatment for severe bleeding under dabigatran was idarucizumab in 96% of protocols, considerably more therapeutic options (mostly different prothrombin complex concentrate (PCC) doses) are described for Xa inhibitors. When considering criteria for effectiveness more than 90% of protocols did not have a clear description.

CONCLUSION

This study provides an overview of the current state of protocols for management of DOAC-related bleeding in The Netherlands. Protocols vary in the content of information provided and often do not include information, especially for diagnostic criteria and criteria for establishing the effectiveness of the intervention. The results of this study can assist in improving and harmonizing the protocols.