LAUSR

Transcatheter aortic valve implantation (TAVI) has emerged over the last decade as a viable treatment option for patients with severe symptomatic aortic stenosis (AS) across all risk strata with TAVI procedural volumes increasing significantly over time and currently exceeding surgical aortic valve replacement surgery volumes in the USA [1]. The most common complication associated with TAVI is vascular bleeding, which portends a higher mortality risk [2]. Bleeding risk is related to a combination of patient-related factors and pharmacotherapies. Therefore, it is increasingly important to choose, in a shared-decision making process with the patient, the appropriate antithrombotic therapy post-TAVI that will balance bleeding risk with thromboembolic events and long-term valve function to give the best outcomes for patients. This is an important area of consideration as subclinical leaflet thrombosis appears to be more common after TAVI than surgical valve replacement (up to 10–15% in some series) and is associated with increased risk of cerebrovascular events [3, 4]. In the pivotal PARTNER trials [5], the antithrombotic therapy chosen after TAVI was aspirin and clopidogrel for 6 months, which became the default pharmacotherapeutic approach. However, several randomized controlled trials tried recently to address the issue regarding antithrombotic therapy, with choices including single anti-platelet therapy (SAPT), dual anti-platelet therapy (DAPT), and/or anticoagulation. These investigations parallel the ongoing debate about antithrombotic therapy after percutaneous coronary intervention. The trials of particular note are ARTE (Aspirin versus Aspirin Plus Clopidogrel Following TAVI), GALILEO (Global Study Comparing a Rivaroxaban-Based Antithrombotic Strategy to an Anti-platelet-Based Strategy After Transcatheter Aortic Valve Replacement to Optimize Clinical Outcomes), and the POPular TAVI study. In the smaller ARTE trial of 222 patients [6], aspirin monotherapy — as compared with the combination aspirin and clopidogrel — was associated with significantly lower major or life-threatening bleeding without a difference in death, myocardial infarction, or stroke. This finding was supported by the larger study POPular TAVI trial [7] (N = 665 patients), in which the rates of cardiovascular death, stroke, or myocardial infarction were not different between SAPT or DAPT; however, the hazards of major and minor bleeding were significantly higher with DAPT (15.1% with SAPT vs 26.6% with DAPT). Interestingly, there were numerically higher cases of symptomatic aortic valve thrombosis with aspirin alone (3 patients versus 1), but the significance of this finding is unclear given the small numbers. Both studies therefore suggested that aspirin monotherapy after TAVI may be safer and is not associated with a higher risk of adverse outcomes. However, the evidence was far from conclusive given the small sample size and short duration of follow-up in both studies. The emergence of the serious concern of subclinical leaflet thrombosis and the associated higher risk of cerebrovascular events also led to the investigation of anticoagulation as an alternative therapeutic approach. In the GALILEO [8] trial, patients were randomized to rivaroxaban and aspirin for 4 months followed by rivaroxaban alone or to DAPT for 3 months then aspirin alone. Although rivaroxaban use was associated with lower subclinical leaflet abnormalities, it significantly increased the risk of mortality without decreasing thromboembolic events. This resulted in an early termination of the study. Similarly, results from the ATLANTIS trial investigating apixaban [9] were presented at the American College of Cardiology Scientific Session 2021. In this study, apixaban (5 mg twice daily) was compared to anti-platelet therapy. Like GALILEO, apixaban reduced valve leaflet thrombosis but was associated with higher non-cardiovascular mortality and no benefit in death, MI, or stroke. It wasn’t clear why there was no benefit observed * Hani Jneid [email protected]