Efficacy and Safety of Nonvitamin K Oral Anticoagulants following Cardiac Valve Replacement

Mary K. Stuart, PharmD, BCPS; Sarah B. Blackwell, PharmD, BCCCP; Hillary B. Holder, PharmD, BCPS; Elizabeth L. Wood, PharmD; Jessica A. Starr, PharmD, BCPS

Disclosures

South Med J. 2021;114(1):46-50. 

In This Article

Abstract and Introduction

Abstract

Objective: To compare the efficacy and safety of nonvitamin K oral anticoagulants (NOACs) and vitamin K antagonists (VKAs) following bioprosthetic cardiac valve replacement.

Methods: This was a retrospective analysis conducted at a community teaching hospital in the southeastern United States between August 2015 and August 2018. Patients 18 years of age and older who underwent cardiac valve replacement and were prescribed oral anticoagulation were screened for inclusion. Patients were excluded if they had a mechanical valve replacement, experienced a venous thromboembolism, cerebrovascular accident, or acute coronary syndrome within 1 month before valve replacement, changed oral anticoagulation during the study period, were lost to follow-up, or declined to participate in the follow-up survey. The primary outcome was a composite of thromboembolic events within 90 days following bioprosthetic cardiac valve replacement. The safety outcome was major bleeding within 180 days of bioprosthetic cardiac valve replacement.

Results: The primary outcome of a composite of thromboembolic events within 90 days following bioprosthetic cardiac valve replacement occurred in 1 patient (4.3%) in the VKA group and 4 patients (7.4%) in the NOAC group. Major bleeding occurred in 2 patients (8.7%) in the VKA group and 0 patients in the NOAC group.

Conclusion: Our study is the first to report the efficacy and safety of NOACs compared with VKA therapy following bioprosthetic cardiac valve replacement irrespective of an atrial fibrillation diagnosis. Notably, two of the thromboembolic events in the NOAC group occurred while therapy was held or inappropriately dosed; when these events are removed, the rate of thromboembolism is 3.8%. This rate is consistent with the VKA group. Our study adds to a small pool of literature regarding the use of NOACs following bioprosthetic cardiac valve replacement and suggests that NOACs may have similar efficacy and improved safety as compared with VKA therapy. Large randomized controlled trials are warranted to confirm our observations.

Introduction

Valvular heart disease is a growing health problem, with an estimated 2.5% of the US population affected.[1] The disease often is degenerative and progressive in nature, causing a disproportionate rise in incidence in those older than 65 years. Many patients deteriorate and require surgical or transcatheter intervention to reestablish valve function and improve prognosis. Cardiac valve repairs and replacements account for 10% to 20% of all cardiac surgical procedures.[1,2] There is an increased risk of thromboembolic complications following cardiac valve replacement, with a peak incidence during the first 3 months after surgery. Thrombotic potential varies based on valve type and position; however, many patients require either short- or long-term anticoagulation.[3]

As a result of the ease of dosing and improved safety profiles, nonvitamin K oral anticoagulants (NOACs) are preferred over vitamin K antagonists (VKAs) in several disease states requiring oral anticoagulation, including atrial fibrillation (AF) and venous thromboembolism (VTE);[4,5] however, current guidelines do not recommend the use of NOACs following cardiac valve replacement. Both the American College of Chest Physicians (ACCP) and the American College of Cardiology/American Heart Association Task Force (ACC/AHA) recommend VKA therapy for patients with mechanical valve prostheses.[6,7] In addition, the ACC/AHA recommends against the use of NOACs in this population, citing harm.[7] This recommendation is based on results of the RE-ALIGN (Dabigatran Etexilate in Patients with Mechanical Heart Valves) trial comparing dabigatran with VKA therapy in patients following mechanical valve replacement, which was stopped prematurely because of excessive rates of thromboembolism and bleeding in the dabigatran group.[8] These negative data have been extrapolated to all NOACs, as RE-ALIGN is the only major trial to date to evaluate the use of a NOAC in patients with prosthetic valves. In contrast, the optimal antithrombotic regimen following a bioprosthetic cardiac valve replacement is more variable. The ACCP recommends VKA therapy for the first 3 months after bioprosthetic mitral valve replacement and aspirin over VKA therapy for the first 3 months following bioprosthetic aortic valve replacement.[6] The ACC/AHA suggests anticoagulation with a VKA for at least 3 months following either bioprosthetic mitral or aortic valve replacement.[7] Notably, there are no recommendations for the use of NOACs following bioprosthetic cardiac valve replacement from either ACCP or ACC/AHA.[6,7]

Despite the paucity of data regarding the safety and efficacy of NOACs following bioprosthetic cardiac valve replacement, there is an apparent increase in NOAC prescribing in this population. Beller et al[9] reviewed >30,000 cardiac surgery patients, 11,632 of whom received bioprosthetic cardiac valve replacement. Anticoagulation patterns were compared during two 3-year periods, 2011–2014 and 2015–2018. Although there was no difference in overall rates of anticoagulation between the two periods (31.9% vs 31.6%), the rate of NOAC prescribing increased nearly sixfold during the second time frame (from 6.6% to 32.1%, P < 0.001).[9]

At our institution an average of 550 cardiac surgeries were performed per year from August 2015 to August 2018, with cardiac valve replacements accounting for approximately 25% of these cases. Similar to the findings of Beller et al, an increase in the prescription of NOACs following cardiac surgery was noted, especially after bioprosthetic cardiac valve replacement.[9] Despite an increase in use, data on safety and efficacy outcomes for NOACs following bioprosthetic cardiac valve replacement are lacking. The purpose of this study was to compare the efficacy and safety of NOACs versus VKA following bioprosthetic cardiac valve replacement.

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