The defective heart valve would come off the market three years later, due to problems with the silver coating and the potential for valve leak. The health regulator in the UK was first to raise the red flag over the St. Jude Silzone heart valve in November 1999, according to an exhaustive summary published by Mondaq Business Briefing earlier this year. Regulators in New Zealand and Australia went one step further and ordered a complete recall of the problematic heart valve that same month.
The FDA took a little longer, however—finally securing (through negotiations with St. Jude Medical) a recall of the Silzone mechanical heart valve in late January 2000. For its part, the St. Jude website contains several archived documents, including a letter St. Jude sent to physicians dated January 21st of that year regarding the potential for paravalvular leak "between the upper and lower chambers of the heart around the outside of the [defective heart] valve," according to the web site.
Critics of the problematic St. Jude heart valve—and the accelerated approval process that paved its way onto the market in the first place—note that the use of silver was an untried concept in cardiac applications prior to the Silzone mechanical heart valve. Silver was widely held as being toxic and a potential carcinogen, and there were no clinical studies available.
And yet the manufacturer made the case to regulators that adding silver to the sewing cuff of the valve could decrease the possibility of bacterial endocarditis (infection). Given that St. Jude Medical had enjoyed an exemplary track record with mechanical heart valves spanning two decades—and that the Silzone mechanical heart valve was an update to a device already on the market—the product soon prone to valve leak was spared a more time-consuming and costly approvals process, according to FDA guidelines. It has been reported the defective heart valve was granted approval through the SPMA (Supplementary Pre Market Approval) protocol, which is a higher tier in the accelerated approval process.
Alternatively, approval based on the 510(k) guideline can be undertaken based on a review encompassing fewer than 50 days, according to Mondaq (1/25/12).
A clinical trial for the device was mounted nonetheless, but after the St. Jude heart valve was already on the market and implanted into thousands of people. The Artificial Valve Endocarditis Reduction Trial, or 'AVERT,' had to be scrubbed prior to completion due to incidence of valve leak.
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This was little comfort for the thousands of Silzone mechanical heart valve patients made to live with a defective heart valve—especially one tagged with an increased risk for stroke, reversible ischaemic neurological deficits and valve thrombosis (blood clot). That risk was borne out of the halted clinical trial, and while the increased risk was considered statistically insignificant, the possibility for failure has left many St. Jude Silzone patients unsettled at best.
Such doubt has driven many to consider legal action given that they have been made to live with a potentially defective heart valve.