NOACs preferable over warfarin in AF patients with bioprosthetic valves

Use of nonvitamin K oral anticoagulants (NOACs) results in a reduced incidence of thromboembolic events and major bleeding relative to warfarin in patients with atrial fibrillation (AF) and bioprosthetic valves or valve repair, suggests a study.

“Patients with AF and a history of bioprosthetic valves or valve repair had a lower incidence of stroke or systemic embolism and major bleeding events when anticoagulated with NOACs as compared with warfarin therapy,” the researchers said. “These findings suggest that NOACs may be preferred over warfarin in this patient population.”

A systematic search was conducted using the databases of PubMed, Embase, and Cochrane for randomized controlled trials comparing NOACs to warfarin in patients with AF and bioprosthetic valves or valve repair. Outcomes for stroke or systemic embolism, ischaemic stroke, haemorrhagic stroke, and major bleeding were pooled.

Four trials met the eligibility criteria and included a total of 1,379 patients, of whom 723 (52.4 percent) received a NOAC. Mean follow-up ranged from 90 days to 2.8 years. [Am J Med 2022;135:228-234.E1]

Pooled analysis revealed a significantly lower incidence of stroke or systemic embolism in patients treated with NOACs compared with warfarin (1.9 percent vs 3.7 percent; odds ratio [OR], 0.43, 95 percent confidence interval [CI], 0.22‒0.85; p=0.02).

No significant between-group difference was observed in ischaemic stroke (OR, 0.72, 95 percent CI, 0.18‒2.93), haemorrhagic stroke (OR, 0.18, 95 percent CI, 0.03‒1.05), cardiovascular death (OR, 0.78, 95 percent CI, 0.38‒1.62), and all-cause mortality (OR, 0.94, 95 percent CI, 0.55‒1.62).

However, major bleeding was significantly lower in patients who received NOAC than those on warfarin (2.8 percent vs 4.7 percent; OR, 0.49, 95 percent CI, 0.28‒0.88; p=0.02).

“The addition of aspirin to oral anticoagulation is associated with a 1.5- to 2-fold increase in the risk of major bleeding events,” the researchers said. [Cochrane Database Syst Rev 2013;CD003464; N Engl J Med 2019;380:1509-1524]

“Therefore, the incidence of major bleeding in the population of this meta-analysis must be considered under the perspective of a relatively low rate of concomitant aspirin use in the study population (approximately 16 percent),” they added.

Of note, the finding of fewer cerebrovascular events with NOACs relative to warfarin was not unexpected. For instance, an earlier study (ARISTOTLE Trial) reported a lower incidence of stroke in patients randomized to apixaban vs warfarin (1.19 percent vs 1.51 percent per year; hazard ratio, 0.79, 95 percent CI, 0.65‒0.95; p=0.01). [N Engl J Med 2011;365:981-992]

ACC/AHA Guidelines

Specific recommendations for the use of NOACs in patients with bioprosthetic valves were not issued in the 2019 American College of Cardiology/American Heart Association (ACC/AHA) Focused Update on Atrial Fibrillation and the 2020 ESC Guidelines for the Diagnosis and Management of Atrial Fibrillation, but comparable results to warfarin in smaller studies were discussed. [Circulation 2019;140:e125-e151; Eur Heart J 2021;42:373-498]

On the other hand, the 2020 ACC/AHA Guideline for the Management of Valvular Heart Disease assigns a class 1 recommendation for NOAC use as an alternative to warfarin in patients with AF and bioprosthetic valves after 3 months of implant. [Circulation 2021;143:e72-e227]

“In light of the findings of … the current meta-analysis, NOACs may potentially be preferred over warfarin in this population,” the researchers said.