The Medtronic Sprint Fidelis Lead debacle highlights many of the shortcomings that exist in the way the Food & Drug Administration (FDA) regulates medical devices, according to a recent editorial in the New England Journal of Medicine (NEJM). Medtronic recalled its Sprint Fidelis Lead last October, after it was determined that the lead had a high rate of fracturing.
Medtronic suspended sales of the Sprint Fidelis Leads in October, after receiving reports of 5 fatalities linked to lead fractures. A lead is a wire that connects an implantable defibrillator to the heart. When it breaks, the defibrillator can emit a massive and painful shock. And in the worse case scenario, the fractured lead can prevent a defibrillator from sending a necessary, lifesaving shock to the heart. Replacing a lead is not an easy procedure, as the invasive surgery can cause the tissue of the blood vessels and heart to tear. In fact, replacing a defibrillator lead is so risky that patients with Sprint Fidelis Leads were told to leave the defective components in place unless they fracture.
The Sprint Fidelis Lead was designed to replace Medtronic’s Sprint Quattro models, and it is one of the thinnest defibrillator lead wires on the market. Since it was put on the market in 2004, Sprint Fidelis Leads have been implanted with 90% of Medtronic’s defibrillators. But according to an editorial appearing in the March issue of the NEJM, not only was the Sprint Fidelis Lead never tested in humans, and both Medtronic and the FDA had received reports of problems with the lead long before the October 2007 recall.
When the FDA approved the Medtronic Sprint Fidelis Lead in 2004 , it did so on the basis of bench testing but no human clinical data. That’s because the Sprint Fidelis was considered an improvement or modification of the existing Sprint Quatro Lead. In such cases, the FDA requires no testing in humans.
By March 2007, Medtronic had received a disturbing number of reports about the Sprint Fidelis Lead’s high fracture rate. According to the NEJM editorial, Medtronic sent physicians a letter informing them that “a limited number” of physicians were seeing a higher-than-expected rate of lead fractures. Medtronic concluded that the lead’s performance was “in line with other Medtronic leads” on the basis of two main factors: analysis of returned products and a small prospective postmarketing study that found a 1.1% rate of lead failure within 2 years of implantation. But that postmarketing study included fewer than 100 patients followed for 2 years. According to the editorial, it was “grossly underpowered to detect even a moderate increase in fracture rate in the Fidelis as compared with its predecessors”. Medtronic then began collecting and analyzing data from more than 25,000 patients participating in its remote monitoring program.
Then, Medtronic submitted an FDA application for design and manufacturing changes to the Sprint Fidelis Lead in May 2007 and, according to the FDA’s public premarket approval database, received approval 2 months later. While it was waiting for the approval, Medtronic was allowed to maintain that the Sprint Fidelis Lead was safe, and the company allowed already-manufactured leads to continue to be implanted. By October 2007, Medtronic had confirmed the occurrence of 665 fractures in returned leads, and a 2.3% fracture rate within 30 months of implantation. It was only then that Medtronic voluntarily recalled the defective Sprint Fidelis Leads.
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