Thrombosis of Surgical Bioprosthetic Heart Valves-Insights from Reports to International Medical Device Vigilance Systems

Objectives: Although recognized as rare finding, thrombosis of tissue bioprostheses is a serious complication in valve replacement therapy. Recent reports on reduced leaflet motion due to subclinical thrombosis of transcatheter and surgical valves lead to further investigation of thrombotic processes on these devices. With investigating reports from German and American device vigilance systems we aimed to add important information on this issue.

Methods: All reports in connection with thrombosis of biological heart valve prostheses which had been reported anonymously to a German medical device vigilance system (GVS) from 2000 to 2009 were identified. All available clinical and device-specific data as well as investigation results of explanted devices were analyzed. In a second step the available (2006 to 2015) FDA's Manufacturer and User Facility Device Experience (MAUDE) database was searched for reports connected to tissue valve thrombosis.

Results: 38 incident reports regarding thrombosis (n = 32) or fibrin (n = 6) on various aortic and mitral bioprostheses were identified in the GVS. All devices consisted of porcine tissue (100%), 97.3% were stented valves. In 78,95% (n = 30) reports a glutaraldehyde fixated valve, treated with a specific anticalcification solution, was affected. Failure due to thrombosis occurred in 53.1% within 1 year, in 67.7% thrombus was found on the outflow surface of the valve, in 64.5% all 3 cusps were involved. One pat (2.6%) died during re-operation. In MAUDE 367 incidents were identified, mortality rate was 6.5%. In 243 (66.2%) reports porcine valves were affected.

Conclusion: The reporting rate of thrombotic complications concerning surgical tissue prostheses is low both in Germany and the US. However, incident reports in both countries suggest higher rates in porcine valves. Our observation of definite thrombus formation in the aortal aspect of cusps is consistent with the recent finding of subclinical leaflet thrombosis as preceding, still reversible, process in the same area.