Prosthetic Heart Valve Thrombosis

Although surgery was the mainstay of treatment for valvular heart disease, transcatheter valve therapies have grown exponentially over the past decade. Two types of artificial heart valve exist: mechanical heart valves (MHV), which are implanted surgically, and bioprosthetic heart valves (BHV), which can be implanted via a surgical or transcatheter approach. Whereas long-term anticoagulation is required to prevent thromboembolism after MHV replacement, its value in patients receiving BHVs is uncertain. Patients undergoing transcatheter BHV replacement are at risk for thromboembolism in the first few months, and recent data suggest that the risk continues thereafter. BHV thrombosis provides a substrate for subsequent thromboembolism and may identify a reversible cause of prosthesis dysfunction. Hereafter, the authors: 1) review the data on prosthetic valve thrombosis; 2) discuss the pathophysiological mechanisms that may lead to valve thrombus formation; and 3) provide perspective on the implications of these findings in the era of transcatheter valve replacement. (C) 2016 by the American College of Cardiology Foundation.