Considerations in antithrombotic therapy among patients undergoing transcatheter aortic valve implantation

Aortic stenosis (AS) accounts for the majority of valvular abnormalities requiring surgical intervention. Platelet dysfunction has been demonstrated among patients with severe aortic stenosis which may predispose patients to bleeding or ischemic events. Surgical aortic valve replacement (AVR) is the standard therapy for severe symptomatic AS; however, a number of patients have very high or prohibitive surgical risk. Transcatheter aortic valve implantation (TAVI) has been shown to be superior to medical therapy among inoperable patients and non-inferior to AVR in patients with high surgical risk. In comparison to AVR, TAVI has been associated with a higher incidence of ischemic cerebrovascular events, conduction abnormalities necessitating permanent pacemaker placement, and vascular complications. Current practice guidelines recommend dual antiplatelet therapy (DAPT) following TAVI using a combination of low dose aspirin and clopidogrel for 3-6 months. This regimen may be adjusted in patients with clinical bleeding events or indications for concomitant systemic anticoagulation. Recent and ongoing trials aim to clarify the optimum antithrombotic regimen and duration of therapy following TAVI. Collectively, early studies have not revealed additional benefit of adding clopidogrel to aspirin therapy in regards to reducing ischemic events, but have shown a trend towards increase in major bleeding. TAVI has proven successful, and as its breadth of utility is expanded, further studies are needed to define optimum antithrombotic therapy following TAVI. This article will review the current data for antiplatelet and anticoagulant therapy following TAVI.