St. Jude Heart Valve
People implanted with St. Jude mechanical heart valves with Silzone coated sewing cuffs ("silzone valves") may be at higher risk for paravalvular leak. For this reason, on January 21, 2000, St. Jude Medical Inc. instituted a recall of all silzone valves that had not yet been implanted into patients.
There is also a concern that persons implanted with silzone valves face higher risks of thrombus formation, thrombosis and stroke. A thrombus is a blood clot that can form upon the valve, affecting its operation or even rendering it inoperable. Thrombosis is a condition in which blood clots form and then move through the blood stream. These clots can ultimately cause a transient ischemic attack (TIA) or a stroke due to thromboembolism.
In November of 1999, The Medical Device Agency in London issued an Advice entitled "Thromboembolic Complications involving Silzone® Mechanical Heart Valves." This bulletin reported a study in the United Kingdom of 51 patients implanted with silzone valves. Seven of these patients suffered a stroke. Upon reviewing the data, the Society of Cardiothoracic Surgeons of Great Britain and Ireland confirmed that there is a greater thromboembolic event rate associated with silzone valves compared to standard St. Jude mechanical heart valves. This data was presented at a recent meeting of the American Heart Association in Atlanta.
That data compared two groups of patients, 118 persons implanted with standard St. Jude valves and 75 patients implanted with silzone valves. The data showed that persons implanted with the silzone valves had much higher incidences of stroke and major embolism. The increase in incidence was greatest among patients implanted with either a mitral silzone valve or both a mitral and aortic silzone valve.