North American Thrombosis Forum, AF Action Initiative Consensus Document

Catheter ablation approach and outcome in HIV+ patients with recurrent atrial fibrillation

INTRODUCTION

Earlier studies have shown a clear association between severity of human immunodeficiency virus (HIV) infection and incident atrial fibrillation (AF). We present the long-term outcome of catheter ablation (CA) and electrophysiological characteristics in HIV+ AF patients.

METHODS

This study evaluated 1438 consecutive AF patients [31 (2.15%) with HIV and 1407 (97.8%) without HIV diagnosis] undergoing their first CA at our center. A total of 31 HIV patients and 31 controls were generated by propensity matching, based on calculated risk factor scores, using a logistic model. During first procedure, all received isolation of pulmonary vein (PV) + posterior wall and superior vena cava. Non-PV triggers, defined as ectopic triggers originating from sites other than PVs, were identified at the redo ablation with high-dose isoproterenol challenge.

RESULTS

Clinical characteristics were not different between the groups. When compared to the control, by the end of 5 years after the first procedure, recurrence was significantly greater in HIV group [100% vs. 54%, p < .001]. Among patients that underwent redo ablation non-PV triggers were higher in HIV group [93.5% vs. 54%, p < .001], and most frequently originated from the coronary sinus [67.7% vs. 45.2%, p < .001] and left atrial appendage [41.9% vs. 25.8%, p < .001]. After focal ablation of non-PV trigger, no difference in arrhythmia recurrence between two groups [80.6% vs. 87.1%, p = .753] at 1-year follow up was found.

CONCLUSION

Our findings suggest that non-PV triggers are highly prevalent in HIV+ AF patients resulting in higher rate of the mid- and long-term arrhythmia recurrence.

Electronic alerts for ambulatory patients with atrial fibrillation not prescribed anticoagulation: A randomized, controlled trial (AF-ALERT2)

BACKGROUND

Despite widely available risk stratification tools, safe and effective anticoagulants, and guideline recommendations, anticoagulation for stroke prevention in atrial fibrillation (AF) is under-prescribed in ambulatory patients. To assess the impact of alert-based computerized decision support (CDS) on anticoagulation prescription in ambulatory patients with AF and high-risk for stroke, we conducted this randomized controlled trial.

METHODS

Patients with AF and CHA₂DS_2-VASc score ≥ 2 who were not prescribed anticoagulation and had a clinic visit at Brigham and Women's Hospital were enrolled. Patients were randomly allocated, according to Attending Physician of record, to intervention (alert-based CDS) versus control (no notification). The primary efficacy outcome was the frequency of anticoagulant prescription.

RESULTS

The CDS tool assigned 395 and 403 patients to the alert and control groups, respectively. Alert patients were more likely to be prescribed anticoagulation within 48 h of the clinic visit (15.4 % vs. 7.7 %, p < 0.001) and at 90 days (17.2 % vs. 9.9 %, p < 0.01). Direct oral anticoagulants were the predominantly prescribed form of anticoagulation. No significant differences were observed in stroke, TIA, or systemic embolic events (0 % vs. 0.8 %, p = 0.09), symptomatic VTE (0.5 % vs. 1 %, p = 0.43), all-cause mortality (2 % vs. 0.7 %, p = 0.12), or major adverse cardiovascular events (2.8 % vs. 2.5 %, p = 0.79) at 90 days.

CONCLUSIONS

An alert-based CDS strategy increased a primary efficacy outcome of anticoagulation in clinic patients with AF and high-risk for stroke who were not receiving anticoagulation at the time of the office visit. The study was likely underpowered to assess an impact on clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier- NCT02958943.

Performance of the microINR Point-of-Care System Used by Self-Testing Patients: A Multicenter Clinical Trial

Introduction  Anticoagulation monitoring is a major practical and clinical challenge. We assessed the performance of the microINR system in patient self-testing (PST). Methods  This study was performed at four US medical centers. After the training visit of warfarin anticoagulated patients ( n  = 117) on microINR system, PST was performed at home and in two visits to the medical centers. At the medical centers, both PST and healthcare professionals (HCPs) performed duplicate tests with the microINR System. A venous blood sample for the laboratory testing was also extracted. Accuracy and precision were assessed. Results  The comparison between microINR PST results and microINR HCP results revealed an equivalence with a slope of 1.00 (95% confidence interval [CI]: 1.00-1.00), and an intercept of 0.00 (95% CI: 0.00-0.00). When compared with the laboratory analyzer, microINR PST results also showed good correlation with a slope of 0.94 (95% CI: 0.86-1.04) and an intercept of 0.14 (95% CI: -0.09-0.34). Predicted bias values at international normalized ratio (INR) 2.0, 3.5, and 4.5 were 0% against HCP and ≤2.5% against the laboratory. Analytical agreement with both HCP and laboratory was 100% according to ISO17593 and 99.1 and 100% according to CLSI POCT14 with HCP and laboratory, respectively. Clinical agreement with HCP regarding 2.0-4.0 as INR therapeutic range was 98% (within range). The precision (coefficient of variation) of microINR system used by PST was comparable to HCP. Conclusion  The microINR results when used by self-testing patients show satisfactory concordance to both HCP results and laboratory analyzer. The microINR system is adequate for self-testing use.

Alert-based computerized decision support for high-risk hospitalized patients with atrial fibrillation not prescribed anticoagulation: a randomized, controlled trial (AF-ALERT)

AIMS

Despite widely available risk stratification tools, safe and effective anticoagulant options, and guideline recommendations, anticoagulation for stroke prevention in atrial fibrillation (AF) is underprescribed. We created and evaluated an alert-based computerized decision support (CDS) strategy to increase anticoagulation prescription in hospitalized AF patients at high risk for stroke.

METHODS AND RESULTS

We enrolled 458 patients (CHA2DS2-VASc score ≥1) with AF who were not prescribed anticoagulant therapy and were hospitalized at Brigham and Women's Hospital. Patients were randomly allocated, according to Attending Physician of record, to intervention (alert-based CDS) vs. control (no notification). The primary efficacy outcome was the frequency of anticoagulant prescription. The CDS tool assigned 248 patients to the alert group and 210 to the control group. Patients in the alert group were more likely to be prescribed anticoagulation during the hospitalization (25.8% vs. 9.5%, P < 0.0001), at discharge (23.8% vs. 12.9%, P = 0.003), and at 90 days (27.7% vs. 17.1%, P = 0.007). The alert reduced the odds of a composite outcome of death, myocardial infarction (MI), cerebrovascular event, and systemic embolic event at 90 days [11.3% vs. 21.9%, P = 0.002; odds ratio (OR) 0.45; 95% confidence interval (CI) 0.27-0.76]. The alert reduced the odds of MI at 90 days by 87% (1.2% vs. 8.6%, P = 0.0002; OR 0.13; 95% CI 0.04-0.45) and cerebrovascular events or systemic embolism at 90 days by 88% (0% vs. 2.4%, P = 0.02; OR 0.12; 95% CI 0.0-0.91).

CONCLUSION

An alert-based CDS strategy increased anticoagulation in high-risk hospitalized AF patients and reduced major adverse cardiovascular events, including MI and stroke.

CLINICALTRIALS.GOV IDENTIFIER

NCT02339493.

Patients with perceived high-bleeding risk and computerized decision support for stroke prevention in atrial fibrillation: an AF-ALERT substudy : Piazza: outcomes of high-bleeding risk AF patients

A perceived increased risk of bleeding is one of the most frequent reasons for withholding anticoagulation for stroke prevention in atrial fibrillation (AF). We previously conducted a randomized controlled trial of alert-based computerized decision support to increase prescription of anticoagulation in hospitalized patients with AF. To determine the clinical characteristics and outcomes of those patients whose inpatient health care providers received a computer alert, we analyzed all 248 patients in the alert group. Patients for whom providers elected to omit anticoagulation and provided a rationale of a perceived high risk of bleeding were compared with those who were not designated as high-risk. Perceived high risk of bleeding was the most common reason (77%) for omitting anticoagulation. Median HAS-BLED scores were similar in these patients compared with those who were not deemed to have an increased bleeding risk (3 vs. 3, p = 0.44). Despite being categorized as too high-risk for bleeding to receive antithrombotic therapy at the time of the alert, nearly 12% of these patients were ultimately prescribed anticoagulation by 90 days. The frequency of major and clinically-relevant non-major bleeding was similar between the groups. The frequency of death, myocardial infarction, stroke, or systemic embolic event was similar in both groups (10.2% vs. 12.4%, p = 0.59). In conclusion, a perceived high risk of bleeding was the most common reason for omission of anticoagulation in patients with AF after a computerized alert. Perceived high risk of bleeding was not reflected in a higher HAS-BLED score.Clinical trial registration: ClinicalTrials.gov Identifier: NCT02339493 https://clinicaltrials.gov/ct2/show/NCT02339493 In a randomized controlled trial of computerized decision support to increase prescription of antithrombotic therapy in hospitalized patients with atrial fibrillation (AF), a perceived high risk of bleeding was the most common reason (77%) for omitting antithrombotic therapy after an on-screen alert. Median HAS-BLED scores were similar in these patients compared with those who were not deemed to have an increased bleeding risk (3 vs. 3, p = 0.44). Despite being categorized as too high-risk for bleeding to receive antithrombotic therapy for stroke prevention at the time of the alert, nearly 12% of these patients were ultimately prescribed anticoagulation over the ensuing 90 days.

Edoxaban versus Warfarin in Patients with Atrial Fibrillation at the Extremes of Body Weight: An Analysis from the ENGAGE AF-TIMI 48 Trial

BACKGROUND

 The effects of anticoagulants at extremes of body weight (BW) are not well described. The aim of this study was to analyze the pharmacokinetics/pharmacodynamics and clinical outcomes in patients randomized to warfarin, higher dose edoxaban (HDER), and lower dose edoxaban (LDER) regimens at extremes of BW in ENGAGE AF-TIMI 48.

METHODS AND RESULTS

 We analyzed three BW groups: low BW (LBW: <5th percentile, ≤55 kg, N = 1,082), middle BW (MBW: 45th-55th percentile, 79.8-84 kg, N = 2,153), and high BW (HBW: >95th percentile, ≥120 kg, N = 1,093). In the warfarin arm, LBW patients had higher rates of stroke/systemic embolism (SSE: 6.5 vs. 4.7 in MBW vs. 1.6% in HBW, P _trend < 0.001), major bleeding (MB: 9.3 vs. 7.7 vs. 6.5%, P _trend = 0.08), and worse net clinical outcome of systemic embolic event, MB, or death (31.5 vs. 19.1 vs. 16.0%, P _trend < 0.0001). The time-in-therapeutic range with warfarin was lowest in LBW patients (63.0 vs. 69.3 vs. 70.1% patients, P _trend < 0.001). The pharmacokinetic/pharmacodynamic profile of edoxaban was consistent across BW groups. The risk of SSE was similar between HDER and warfarin for each of the three weight groups (P _int = 0.52, P _int-trend = 0.86). MB was reduced by LDER versus warfarin (P _int = 0.061, P _int-trend = 0.023), especially in LBW patients. Net clinical outcomes were improved by HDER versus warfarin (P _int = 0.087, P _int-trend = 0.027), especially in LBW patients.

CONCLUSION

 Patients with LBW in ENGAGE AF-TIMI 48 had in general a more fragile clinical status and poorer international normalized ratio control. The pharmacokinetic/pharmacodynamic profile of edoxaban was consistent across extremes of BW, resulting in similar efficacy compared with warfarin, while major or clinically relevant non-MB and net outcomes were most favorable with edoxaban as compared to warfarin in LBW patients.

Recombinant activated factor VII (rFVIIa) in refractory haemorrhage for non-haemophiliacs: an eleven-year single-centre experience

Background

Massive bleeding is one of the commonest salvageable causes of death. The search for an ideal haemostatic agent during massive bleeding is still ongoing. One of the novel haemostatic medications is recombinant activated factor VII (rFVIIa). To date, the usage of rFVIIa during massive haemorrhage among non-haemophiliac patients remains off-label. The aim of this study is to report our experience in using rFVIIa to treat refractory bleeding.

Methods

Medical records of all patients treated with rFVIIa for massive bleeding over an eleven-year period in a single institution were recorded. Treatment indications, 24-h and 30-day mortality, changes in transfusion needs and coagulation profiles after rFVIIa administration were analysed.

Results

rFVIIa were administered in 76 patients. Of these, 41 (53.9%) were non-surgical bleeding, followed by 22 patients (28.9%) with trauma, other surgery bleedings in 9 patients (11.8%) and 4 patients (5.4%) with peripartum haemorrhage. Total survival rate was 78.9% within 24 h and 44.7% over 30 days. Among all these patients who had received rFVIIa due to life-threatening haemorrhage, blood and blood product requirements were significantly reduced (P < 0.001), and the coagulation profiles improved significantly (P < 0.05). Two patients with preexisting thromboembolism were given rFVIIa due to intractable bleeding, both survived. No thromboembolic events were reported after the administration of rFVIIa.

Conclusions

rFVIIa significantly improved coagulation parameters and reduced blood product requirements during refractory haemorrhage. Additionally, usage of rFVIIa in trauma and peripartum haemorrhage patients yield better outcomes than other groups of patients. However, the overall mortality rate remained high.

Phenome-wide association studies across large population cohorts support drug target validation

Phenome-wide association studies (PheWAS) have been proposed as a possible aid in drug development through elucidating mechanisms of action, identifying alternative indications, or predicting adverse drug events (ADEs). Here, we select 25 single nucleotide polymorphisms (SNPs) linked through genome-wide association studies (GWAS) to 19 candidate drug targets for common disease indications. We interrogate these SNPs by PheWAS in four large cohorts with extensive health information (23andMe, UK Biobank, FINRISK, CHOP) for association with 1683 binary endpoints in up to 697,815 individuals and conduct meta-analyses for 145 mapped disease endpoints. Our analyses replicate 75% of known GWAS associations (P < 0.05) and identify nine study-wide significant novel associations (of 71 with FDR < 0.1). We describe associations that may predict ADEs, e.g., acne, high cholesterol, gout, and gallstones with rs738409 (p.I148M) in PNPLA3 and asthma with rs1990760 (p.T946A) in IFIH1. Our results demonstrate PheWAS as a powerful addition to the toolkit for drug discovery.

Testing the association between genetic variants and a range of phenotypes can assist drug development. Here, in a phenome-wide association study in up to 697,815 individuals, Diogo et al. identify genotype–phenotype associations predicting efficacy, alternative indications or adverse drug effects.

Practical perspectives on the use of non-vitamin K antagonist oral anticoagulants for stroke prevention in patients with nonvalvular atrial fibrillation: A view from the Middle East and North Africa

Clinical guidelines for the prevention of stroke in patients with nonvalvular atrial fibrillation (NVAF) are available from several international cardiology associations. Patients with NVAF in the Middle East and North Africa (MENA) region present unique challenges and opportunities related to differences in geography, practice patterns, and patient demographics that are as yet unaddressed in practice guidelines. This review aims to offer a practical perspective on the management of NVAF in patients in MENA and draws on evidence-based guidelines as well as real-world evidence and expert opinion. The literature was searched for relevant original research articles, systematic reviews, meta-analyses, and guideline recommendations addressing the prevention of stroke in patients with NVAF with a focus on issues relevant to the MENA region. Guideline recommendations, best practices, and expert opinion were discussed and agreed on by a working group consisting of cardiologists from across the MENA region. The incidence of stroke secondary to atrial fibrillation in patients across the MENA region is higher than rates reported globally, and this might be attributed to a higher incidence of vascular risk factors and underuse of anticoagulants in patients in the MENA. The available evidence supports the established role of non-vitamin K antagonist oral anticoagulants (NOACs) in the prevention of stroke in patients with NVAF. There is a consistent body of clinical trial and real-world evidence supporting their efficacy for stroke prevention in NVAF, with more favorable bleeding risk profiles relative to vitamin K antagonists, such that guidelines now recommend the use of NOACs in preference over vitamin K antagonists. There are important opportunities to improve the management of NVAF outcomes for patients with NVAF by applying evidence-based guidelines for stroke prevention. Growing experience with NOACs in the MENA region will help guide patient selection and elucidate optimal dosing strategies to maximize the clinical benefits of the NOACs.

New Oral Anaticoagulant Prescribing Decisions amongst General Practitioners: Handle with Care

Background: Prescribing oral anticoagulants for atrial fibrillation patients is becoming more challenging as more alternatives enter the market. While warfarin has dominated the market it is a challenging medicine to use owing to its narrow therapeutic range, increased bleeding risk and requirement for continuous monitoring. The introduction of new oral anticoagulants (NOACs) offers a wider choice but they are more costly and their use also brings additional pharmacological considerations. Objective: This paper investigates if the identified risk factors (renal impairment, hepatic impairment, other co-morbidities & drug interactions) influence GPs' NOAC prescribing decisions, using a multivariate probit model, while controlling for other GP characteristics. Methods: Employing primary data, collected using a dedicated survey of Irish GPs in November 2015, a multivariate probit is employed. This measures the joint decision making process of prescribing a NOAC based on four risk factors - renal impairment, hepatic impairment, other comorbidities and drug interactions. Results: Younger GPs are more likely to consider 'other co-morbidities' and 'renal impairment' as important when making NOAC prescribing decisions. Male GPs are more likely to consider 'other co-morbidities' and 'drug interactions' as important when prescribing NOACs compared to female GPs. Prescribers who have initiated NOACs are more likely to consider 'renal impairment' as important compared with non-initiators. Conclusions: Our study highlights the importance for general practitioners prescribing NOACs and caring for patients on oral anticoagulants, of adequate education, of appropriate patient selection and of appropriate monitoring of such patients. While warfarin prescribing remains predominant, NOAC prescribing is increasing. Incorporating the risk factors into prescribing decisions signals responsible prescribing for atrial fibrillation patients. Existing prescribing guidelines/toolkits need to be used in an effective manner.

Creatinine Clearance Is Not Equal to Glomerular Filtration Rate and Cockcroft-Gault Equation Is Not Equal to CKD-EPI Collaboration Equation

Direct oral anticoagulants (DOACs) may require dose reduction or avoidance when glomerular filtration rate is low. However, glomerular filtration rate is not usually measured in routine clinical practice. Rather, equations that incorporate different variables use serum creatinine to estimate either creatinine clearance in mL/min or glomerular filtration rate in mL/min/1.73 m². The Cockcroft-Gault equation estimates creatinine clearance and incorporates weight into the equation. By contrast, the Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations estimate glomerular filtration rate and incorporate ethnicity but not weight. As a result, an individual patient may have very different renal function estimates, depending on the equation used. We now highlight these differences and discuss the impact on routine clinical care for anticoagulation to prevent embolization in atrial fibrillation. Pivotal DOAC clinical trials used creatinine clearance as a criterion for patient enrollment, and dose adjustment and Federal Drug Administration recommendations are based on creatinine clearance. However, clinical biochemistry laboratories provide CKD-EPI glomerular filtration rate estimations, resulting in discrepancies between clinical trial and routine use of the drugs.

Direct oral anticoagulants: unique properties and practical approaches to management

Since 2009, four direct oral anticoagulants (DOACs) have been introduced for treatment of venous thromboembolism and stroke prevention in non-valvular atrial fibrillation. While they are currently first-line therapy for a majority of patients, there are a number of clinical situations where warfarin is preferable. In both randomised trials and real-world populations, use of DOACs significantly reduces the risk of intracranial haemorrhage as compared with warfarin. While drug-specific reversal agents are currently only available for dabigatran, andexanet alpha is pending approval for reversal of factor Xa inhibitors, reducing concerns about major bleeding for many patients and providers. DOACs can be held for 2-4 days prior to a procedure, depending on a patient's renal function, but should not be restarted too rapidly post-procedurally given their fast time to peak activity (∼2 hours). The anticoagulation clinic should play an important role in managing patients on all oral anticoagulation, both warfarin and DOACs.