Comparing novel oral anticoagulants to vitamin k antagonists in patients with hypertrophic cardiomyopathy and atrial fibrillation: an updated systematic review and meta-analysis
Authors: Baghal M , Agarwal KA , Rajkumar D , Santana MS , Patel UP , Magnan DM , Ibrahim MI , Habib MH , Alrestom R , Alabdallat MA , Moussa S , Shamoon F , Gabelman MG , Lo AL 
Published: May 2022

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Atrial fibrillation (AF) is a common occurrence in Hypertrophic cardiomyopathy (HCM), reported in approximately one third of cases. The 2011 ACC guidelines for management of HCM with concomitant AF recommend use of Vitamin K Antagonists (VKA); however, new research and randomized clinical trials present data which favor the use of Novel Oral Anticoagulants (NOAC) over VKA to prevent serious outcomes.

Purpose
We aim to identify the difference between NOAC and VKA in preventing ischemic stroke and thromboembolism, and calculate the rate of intracranial hemorrhage, major bleeding and all cause mortality in both treatment groups.

Methods
We conducted a systematic review and meta-analysis with the aim to answer the following clinical question: What is the efficacy of NOACs vs VKA in preventing thromboembolism and what are the associated risks with each group? We followed PRISMA guidelines. Scientific databases (PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Epistemonikos) were searched using relevant medical subject headings and keywords to retrieve studies published through September 24, 2020. Inclusion criteria were patients over 18 years old, use of NOACs and VKA in atrial fibrillation and HCM. Studies with patients who had catheter ablative therapy were excluded. After an exhaustive review, a total of 6 studies including 2 Randomized Control Trials (RCTs) and 4 retrospective cohort studies were analyzed using RevMan 5.4 to analyze event rate, hazard ratio and 95% confidence interval for ischemic stroke/thromboembolism, all-cause mortality, major bleeding and intracranial hemorrhage. One study was later excluded due to insufficient data. Heterogeneity was assessed by using the I2 statistic.

Results
A total of 9,168 patients [NOAC 5158 and VKA 4010] were pooled. Meta-analysis showed the NOAC treatment group had a significant improvement in preventing the primary outcome ischemic stroke/thromboembolism [HR 0.41; 95% CI 0.26 -0.63, p = &lt;0.001], as well as secondary outcomes; all cause mortality [HR 0.37, 95% CI 0.19 - 0.73, p = 0.004, p = 0.004], Intracranial hemorrhage [HR 0.43; 95% CI, 0.11 - 1.65, p = 0.22], and Major Bleeding [HR 0.56; CI 95% 0.34 - 0.93, p = 0.02].

Conclusion
Anticoagulation of patients with HCM and AF using NOACs was associated with lower risk of ischemic stroke and thromboembolic events in the NOACs group. There was also a statistically significant reduction of all-cause mortality and major bleeding among patients with AF and HCM who had received NOACs as compared to VKA. There was a notable reduction of ICH in the NOACs group as well. Further clinical trials are needed to further assess the long term benefits of using NOACs in these patients.