Direct oral anticoagulants vs. vitamin K antagonists for left ventricular thrombus: a systematic review and meta-analysis

BACKGROUND

Current guidelines recommend vitamin K antagonists (VKAs) to reduce the risk of systemic thromboembolic (STE) events in patients with left ventricular (LV) thrombus. Direct oral anticoagulants (DOACs) are an emerging alternative to VKAs; however, data supporting DOAC use in LV thrombus are still lacking. We conducted this systematic review and meta-analysis to compare the efficacy and safety between DOACs and VKAs in this population.

METHODS

We searched MEDLINE, Embase, and the Cochrane Library databases from inception to October 2020 to identify studies that compared clinical outcomes of interest, including stroke or any STE, LV thrombus resolution, and bleeding, between patients who used DOACs and VKAs for LV thrombus. Data from each study were combined using the random-effects model.

RESULTS

Eight cohort studies with a total of 1771 patients (426 in DOAC group, 1345 in VKA group) were included. There were no statistically significant differences between VKA group and DOAC group on rates of STE events (pooled RR = 1.12, 95% confidence interval [CI]: 0.91-1.39, p = .286), LV thrombus resolution (pooled RR = 1.09, 95% CI: 0.94-1.27, p = .242), or bleeding events (pooled RR = 0.94, 95% CI: 0.59-1.51, p = .808).

CONCLUSIONS

Our meta-analysis found no significant differences in rates of STE events, LV thrombus resolution, or bleeding events between the use of DOACs and VKAs in LV thrombus. Further randomised controlled trials are needed to confirm our findingsHighlightsThere is limited evidence comparing the use of direct oral anticoagulants (DOACs) to vitamin K antagonists (VKAs) in left ventricular (LV) thrombus.Our systematic review and meta-analysis showed that DOACs are not inferior to VKAs in the incidence of systemic thromboembolism (STE), the rate of LV thrombus resolution, and the risk of bleeding.Current evidence is based on observational studies only. Further randomised controlled trials are needed to confirm the findings.

The use of Apixaban for the treatment of an LV thrombus

Summary

A 42-year-old male was admitted with shortness of breath secondary to suspected heart failure and chest infection. An echocardiogram revealed a dilated and impaired left ventricle; ejection fraction 29%, with a large, mobile thrombus within the left ventricular apex. Due to the presence of liver dysfunction, vitamin K antagonists were deemed inappropriate; thus, the decision was taken to use the novel anticoagulation agent Apixaban. After 6 days of receiving Apixaban, a cardiac magnetic resonance scan was preformed, which showed complete resolution of the LV apical thrombus.

Learning points

Patients with a dilated and impaired LV are at an increased risk of developing LV thrombus. A large and mobile LV thrombus is associated with an increased risk of embolic events. Vitamin K antagonists (VKAs) are often the first-line therapy for LV thrombus; however, these may be inappropriate in some patients. NOACs are advantageous in comparison to VKAs and are used to treat: non-valvular atrial fibrillation, pulmonary embolisms and used in the prevention of recurrent deep vein thrombosis in adults. To date, NOACs are not licensed for the treatment of an LV thrombus; however, there are growing evidence whereby there use has shown promise in reducing the risk of embolic events and demonstrate rapid reduction in size/full resolution of an LV thrombus. Large, randomised research trials comparing NOACs and VKAs in the treatment of LV thrombus are needed, which may lead to a change in standard clinical practice that could benefit patients.