Efficacy and safety of novel oral anticoagulants in clinical practice: a report from three centers in Sweden

Mechanical prosthetic heart valves: Quality of anticoagulation and thromboembolic risk. The observational multicenter PLECTRUM study

BACKGROUND

Patients with a mechanical prosthetic heart valve implantation need to be treated with a vitamin K antagonist (VKA) due to a substantially high risk of thromboembolism. In this study we report data on patients with mechanical heart valves (MV), with the aim of evaluating the thromboembolic risk in relation to the type and site of implantation, quality of anticoagulation and risk factors associated with thromboembolism.

METHODS

Observational retrospective multicenter study among Centers affiliated to the Italian Federation of Anticoagulation Clinics (FCSA) on patients with MV implanted after 1990 and followed for the management of anticoagulation.

RESULTS

We analyzed 2357 patients with mechanical heart valves (55.2% males), followed for 24,081 years. During the follow-up, 164 thromboembolic events (0.67/100 pt-yrs) and 243 major bleedings (1.0/100 pt-yrs) occurred. The median Time in Therapeutic Range (TTR), calculated in all intended INR classes, was 60% (IQR 47-74%). The rates of thrombotic events were significantly higher in patients intended to stay at therapeutic ranges >INR 2.0-3.0. The presence of atrial fibrillation, history of thromboembolism and of mitral prosthesis were independently associated with thromboembolism. However, a bad quality of anticoagulation (TTR <47%, 25°percentile of our population) was not correlated with thromboembolism.

CONCLUSIONS

A low rate of bleeding and thromboembolic events in patients with mechanical heart valves were found, despite the sub-optimal anticoagulation control. The thromboembolic risk was not associated with the low TTR.

Management and outcome of gastrointestinal bleeding in patients taking oral anticoagulants or antiplatelet drugs

BACKGROUND

Non-vitamin K dependent oral anticoagulants (NOACs) significantly decrease overall major bleeding rates compared with vitamin K antagonists (VKAs) but there is conflicting evidence regarding the relative risk of gastrointestinal bleeding. Since data regarding the types, the management, and the outcome of NOAC-associated gastrointestinal bleeding are scarce, we aimed to fill this gap by comparing cases of gastrointestinal bleeding associated with NOAC, VKA, or antiplatelet therapy.

METHODS

All major gastrointestinal bleeding events documented in the prospective Dresden NOAC registry were identified, and bleeding location, lesion type, endoscopic treatment, use of blood and coagulation factor transfusion, length of stay, and in-hospital mortality were compared with historical data from a large cohort of consecutive gastrointestinal bleeding patients.

RESULTS

In the 143 NOAC therapy cases, upper gastrointestinal tract bleeding was seen in 44.1%, lower gastrointestinal tract bleeding was seen in 42.0%, and no lesion could be identified in the remaining 14.0%. In contrast, upper gastrointestinal tract bleeding was commoner in the 185 VKA therapy cases (53.0%) and in the 711 antiplatelet therapy cases (68.1%). Among cases with upper gastrointestinal tract bleeding during VKA or antiplatelet therapy, 54.1% and 61.4% respectively presented with ulcers, compared with 27.0% for NOAC therapy. In contrast, hemorrhoid bleeding was the predominant lesion type for lower gastrointestinal tract bleeding with NOAC therapy, with a rate of 33.3%, compared with 10.6% with VKA therapy and 8.7% with antiplatelet therapy. NOAC-associated gastrointestinal bleeding resulted in comparatively low resource consumption, shorter hospitalization, and low in-hospital mortality (1.6%) compared with gastrointestinal bleeding historically seen with use of VKAs (in-hospital mortality 5.6%) or antiplatelet agents (in-hospital mortality 11.9%).

CONCLUSIONS

Gastrointestinal bleeding in NOAC recipients is different from that seen with VKA or antiplatelet therapy and has a better short-term prognosis.

Pharmacological and Non-pharmacological Treatments for Stroke Prevention in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is associated with significant risk of stroke and other thromboembolic events, which can be effectively prevented using oral anticoagulation (OAC) with either vitamin K antagonists (VKAs) or non-VKA oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, or edoxaban. Until recently, VKAs were the only available means for OAC treatment. NOACs had similar efficacy and were safer than or as safe as warfarin with respect to reduced rates of hemorrhagic stroke or other intracranial bleeding in the respective pivotal randomized clinical trials (RCTs) of stroke prevention in non-valvular AF patients. Increasing “real-world” evidence on NOACs broadly confirms the results of the RCTs. However, individual patient characteristics including renal function, age, or prior bleeding should be taken into account when choosing the OAC with best risk–benefit profile. In patients ineligible for OACs, surgical or interventional stroke prevention strategies should be considered. In patients undergoing cardiac surgery for other reasons, the left atrial appendage excision, ligation, or amputation may be the best option. Importantly, residual stumps or insufficient ligation may result in even higher stroke risk than without intervention. Percutaneous left atrial appendage occlusion, although requiring minimally invasive access, failed to demonstrate reduced ischemic stroke events compared to warfarin. In this review article, we summarize current treatment options and discuss the strengths and major limitations of the therapies for stroke risk reduction in patients with AF.

Assessment of Patient Adherence to Direct Oral Anticoagulant vs Warfarin Therapy

CONTEXT

Direct oral anticoagulants (DOACs) may be as effective as, and at times safer than, warfarin. Because DOACs do not require regular serum level monitoring, patients' interaction with the health care system may be reduced. To the authors' knowledge, although studies have evaluated warfarin adherence, few studies have evaluated the real-world adherence to DOACs.

OBJECTIVE

To evaluate whether a difference exists between medication adherence of patients taking DOACs vs patients taking warfarin.

METHODS

The electronic medical records of the Anticoagulation Clinic database at Mayo Clinic in Scottsdale, Arizona, were reviewed. Inclusion criteria were adults taking DOACs and a matching cohort taking warfarin between January 1, 2011, and December 30, 2013. The Morisky Medication Adherence Scale-8 item, a validated medication adherence tool, was used to evaluate adherence in both cohorts, and the qualitative covariates were analyzed using ordinal logistic regression.

RESULTS

Of 324 surveys that were sent, 110 patients (34.0%) responded. Most patients took DOACs for atrial fibrillation, and few took DOACs for venous thromboembolism. Overall, 60 of 66 patients (90.9%) in the DOAC group and 42 of 44 patients (95.5%) in the warfarin group reported medium or high adherence. Difference in adherence scores between the 2 groups was not statistically significant (P=.8).

CONCLUSION

Similar adherence was noted between DOACs and warfarin regardless of the frequency of serum level monitoring.

Suboptimal Use of Oral Anticoagulants in Atrial Fibrillation: Has the Introduction of Direct Oral Anticoagulants Improved Prescribing Practices?

BACKGROUND AND OBJECTIVES

Atrial fibrillation (AF) and the associated risk of stroke are emerging epidemics throughout the world. Suboptimal use of oral anticoagulants for stroke prevention has been widely reported from observational studies. In recent years, direct oral anticoagulants (DOACs) have been introduced for thromboprophylaxis. We conducted a systematic literature review to evaluate current practices of anticoagulation in AF, pharmacologic features and adoption patterns of DOACs, their impacts on proportion of eligible patients with AF who receive oral anticoagulants, persisting challenges and future prospects for optimal anticoagulation.

LITERATURE SOURCE AND SELECTION CRITERIA

In conducting this review, we considered the results of relevant prospective and retrospective observational studies from real-world practice settings. PubMed (MEDLINE), Scopus (RIS), Google Scholar, EMBASE and Web of Science were used to source relevant literature. There were no date limitations, while language was limited to English. Selection was limited to articles from peer reviewed journals and related to our topic.

RESULTS

Most studies identified in this review indicated suboptimal use of anticoagulants is a persisting challenge despite the availability of DOACs. Underuse of oral anticoagulants is apparent particularly in patients with a high risk of stroke. DOAC adoption trends are quite variable, with slow integration into clinical practice reported in most countries; there has been limited impact to date on prescribing practice.

CONCLUSION

Available data from clinical practice suggest that suboptimal oral anticoagulant use in patients with AF and poor compliance with guidelines still remain commonplace despite transition to a new era of anticoagulation featuring DOACs.

Effectiveness and safety of dabigatran versus acenocoumarol in 'real-world' patients with atrial fibrillation

Aims

Randomized trials showed non-inferior or superior results of the non-vitamin-K-antagonist oral anticoagulants (NOACs) compared with warfarin. The aim of this study was to assess the effectiveness and safety of dabigatran (direct thrombin inhibitor) vs. acenocoumarol (vitamin K antagonist) in patients with atrial fibrillation (AF) in daily clinical practice.

Methods and results

In this observational study, we evaluated all consecutive patients who started anticoagulation because of AF in our outpatient clinic from 2010 to 2013. Data were collected from electronic patient charts. Primary outcomes were stroke or systemic embolism and major bleeding. Propensity score matching was applied to address the non-randomized design. In total, 920 consecutive AF patients were enrolled (442 dabigatran, 478 acenocoumarol), of which 2 × 383 were available for analysis after propensity score matching. Mean follow-up duration was 1.5 ± 0.56 year. The mean calculated stroke risk according to the CHA₂DS₂-VASc score was 3.5%/year in dabigatran vs. 3.7%/year acenocoumarol-treated patients. The actual incidence rate of stroke or systemic embolism was 0.8%/year [95% confidence interval (CI): 0.2–2.1] vs. 1.0%/year (95% CI: 0.4–2.1), respectively. Multivariable analysis confirmed this lower but non-significant risk in dabigatran vs. acenocoumarol after adjustment for the CHA₂DS₂-VASc score [hazard ratio (HR)_dabigatran = 0.72, 95% CI: 0.20–2.63, P = 0.61]. According to the HAS-BLED score, the mean calculated bleeding risk was 1.7%/year in both groups. Actual incidence rate of major bleeding was 2.1%/year (95% CI: 1.0–3.8) in the dabigatran vs. 4.3%/year (95% CI: 2.9–6.2) in acenocoumarol. This over 50% reduction remained significant after adjustment for the HAS-BLED score (HR_dabigatran = 0.45, 95% CI: 0.22–0.93, P = 0.031).

Conclusion

In ‘real-world’ patients with AF, dabigatran appears to be as effective, but significantly safer than acenocoumarol.

Comparison of Watchman device with new oral anti-coagulants in patients with atrial fibrillation: A network meta-analysis

BACKGROUND

New oral anticoagulants (NOAC) and the Watchman device represent an alternative to warfarin for stroke prophylaxis in atrial fibrillation (AF) patients. However, no studies compare these new treatments. We performed a network meta-analysis to indirectly compare Watchman and NOACs among AF patients.

METHODS

We performed a MEDLINE search for studies comparing warfarin with NOACs (dabigatran, rivaroxaban, apixaban and edoxaban) or Watchman in AF patients with reported clinical outcomes. Mixed treatment comparison model generation was performed to directly and indirectly compare NOACs, warfarin and Watchman.

RESULTS

14 studies with 246,005 patients were included in the analysis, among which 124,823 were treated with warfarin, 120,450 were treated with NOACs and 732 had Watchman implanted. Mean age was 72 ± 9 years, 53% were male, and mean CHADS2 score was 2.1 ± 1.6. Both NOACs and Watchman were superior to warfarin in hemorrhagic stroke prevention (OR = 0.46 [0.30-0.82] and OR = 0.21 [0.05-0.99], respectively). NOACs significantly reduced total stroke (OR = 0.78 [0.58-0.96]) and major bleeding (OR = 0.78 [0.65-0.91]) compared with warfarin. Indirect comparison between NOAC and Watchman revealed no significant differences in outcomes, though there was a trend toward higher rates of ischemic stroke with Watchman compared with NOAC (OR 2.60 [0.60-13.96]) with the opposite findings with hemorrhagic stroke (OR = 0.44 [0.09-2.14]).

CONCLUSIONS

NOAC therapy was superior to warfarin for multiple outcomes while Watchman reduced hemorrhagic stroke. Further studies are needed to assess Watchman versus NOAC to optimize therapy for stroke prevention in AF patients.

Heart Failure and Mortality in Patients With Nonvalvular Atrial Fibrillation Started on Novel Oral Anticoagulant Therapy: A Single-Center Experience

Heart failure (HF) is the leading cause of in-hospital morbidity and mortality in the elderly population. Coexistence of HF and atrial fibrillation (AF) increases the risk of thromboembolic events. Oral anticoagulant therapy reduces the risk of thromboembolic events in patients with AF. Novel oral anticoagulants (NOACs) have been introduced as an alternative drug for prevention from thromboembolic events in patients with nonvalvular AF. The primary aim of this study is to investigate the clinical effects of warfarin, dabigatran, and rivaroxaban in patients with nonvalvular AF. The secondary aim of this study is to reveal the predictors of all-cause mortality in patients with nonvalvular AF undergoing NOACs therapy. The study population consisted of 171 patients with nonvalvular AF. Patients were divided into 3 groups according to the usage of oral anticoagulant therapy including coumadin (51 patients), dabigatran (52 patients), and rivaroxaban (68 patients). Although CHA2DS2-VASc score was similar between groups, HAS-BLED score was significantly higher in patients using rivaroxaban. Dyspepsia and itching were more common in patients using dabigatran. Heart failure and vascular disease were more common in the nonsurviving group (10 patients) than in the surviving group (110 patients) in patients using NOACs. Among age, sex, HF, hypertension, vascular disease, and CHA2DS2-VASc, which were included in the regression model, only the presence of HF was an independent predictor of all-cause mortality in patients using NOACs. In conclusion, the mortality rate is significantly higher in patients with HF using NOACs. Moreover, HF is an independent predictor of all-cause mortality in patients using NOACs.

New Oral Anticoagulants: How Do We Use Them Wisely?

The relative efficacy and safety of new oral anticoagulants (NOAC) have been consistent across a wide range of patients in clinical trials. On the one hand, they have offered new therapeutic options for stroke prevention in patients with atrial fibrillation (AF) and patients do like the experience of no need of frequent blood draws. On the other hand, their expensive prices, different formulary plans from different insurance companies, lack of antidote, and no method of monitoring the therapy are some of the challenges on their use in clinical practice. This narrative review aims to help clinicians understand these new oral anticoagulants better and choose them wisely according to their indications. In addition, other issues related to the use of NOAC, such as cost and methods of reversing their effects in hemorrhagic conditions, are also discussed.

Non-Vitamin K Antagonist Oral Anticoagulant Use in Patients With Atrial Fibrillation and Associated Intracranial Hemorrhage: A Focused Review

Atrial fibrillation (AF) is the most common cardiac arrhythmia and predisposes patients to an increased risk of embolic stroke. After nearly 60 years, warfarin is no longer the only effective therapeutic option for patients with AF. Large randomized trials have consistently shown that non-vitamin K oral anticoagulants (NOACs) including dabigatran, rivaroxaban, apixaban, and edoxaban significantly reduce from the risk of intracranial hemorrhage (ICH) compared with warfarin. We provide a focused review regarding the NOACs and ICH in AF patients by summarizing findings of these large clinical trials, mechanisms of lower ICH, reversal strategies with specific agents, and monitoring strategies.

The Trends in Utilizing Nonvitamin K Antagonist Oral Anticoagulants in Patients With Nonvalvular Atrial Fibrillation: A Real-Life Experience

Dabigatran and rivaroxaban are novel nonvitamin K antagonist oral anticoagulants (NOACs) approved for thromboprophylaxis in atrial fibrillation (AF). In Turkey, like other countries, the efficacy of translation of the clinical trial results and current guideline recommendations into daily clinical practice is yet to be discovered. Using data from medical records of three tertiary care cardiology centers, we identified patients with nonvalvular AF on dabigatran or rivaroxaban treatment. Baseline characteristics and utilization trends were compared between dabigatran and rivaroxaban groups. Secondarily, clinical events including ischemic stroke and/or transient ischemic attack, systemic embolism, and bleeding were evaluated. Among 294 patients with AF included, dabigatran was utilized in 177 (60.2%) and rivaroxaban in 117 (39.8%). Overall, 76% of patients had received long-term warfarin therapy. The use of 110 mg twice a day (55.4%) was the prevailing strategy in dabigatran group, whereas in rivaroxaban group 20 mg every day (67.5%) was the preferred option. Of the patients, 37.3% had severe valvular disease in which mitral regurgitation was the predominant valve abnormality. Scores of CHADS₂, CHA₂DS₂VASc, and HAS-BLED were similar in both the groups. Of the patients, 24% in dabigatran group and 13.7% in rivaroxaban group were prescribed the lower dose inappropriately. The two NOACs did not differ significantly in terms of clinical events. The results of this study indicate that in daily practice, the physicians' behavior in utilizing the NOACs is shaped by the clinical trials and the guideline recommendations. On the other hand, in dose selection, this adherence is not of high quality.