The Björk-Shiley Convexo-Concave valve — a Welded Strut That Snapped and Killed Two-Thirds

When Shiley Inc. and its parent Pfizer pulled the Björk-Shiley Convexo-Concave (BSCC) heart valve from the world market in 1986, the device had been sold for seven years as a refinement of an already trusted prosthesis — and the refinement was the thing that killed people. Co-invented by American engineer Donald Shiley and the Swedish cardiac surgeon Viking Björk, the convexo-concave disc was a geometric tweak meant to improve blood flow over the company’s well-regarded flat-disc tilting valve. To make the new geometry work, the outlet strut that captured the swinging disc was changed and welded to the valve ring. That weld was the flaw. Under the relentless cyclic load of roughly 40 million heartbeats a year, the strut fractured at the weld, the disc escaped, and the valve failed catastrophically — often producing sudden death before the patient could reach an operating room.

The harm was not a rare anomaly tolerated by an unlucky few. Of the roughly 86,000 convexo-concave valves implanted worldwide, more than 600 are documented to have fractured, and in approximately two-thirds of those cases the patient died. The 60-degree version received U.S. Food and Drug Administration approval in 1979; a higher-flow 70-degree variant was sold abroad but never cleared in the United States, and it fractured at even higher rates. Because the failure mode was a fatigue crack that gave no reliable warning, surgeons and patients spent the late 1980s and 1990s trapped in an excruciating calculus: a working valve might snap tomorrow, but elective re-operation to remove it carried its own mortality.

What turned a metallurgical defect into a scandal was the factory. Sworn testimony and a 1984 engineer’s complaint described a Shiley plant in Irvine, California where valves rejected by inspectors were fished back out, reground to hide cracked welds, renumbered, and passed with falsified paperwork — welders were poorly trained, equipment was in “horrible” condition, and struts were forced onto flanges with pliers. The legend of an improved valve concealed a manufacturing line that could not reliably make the one weld on which a patient’s life depended. Litigation, not the FDA, ultimately fixed the price: the Bowling v. Pfizer class action settled in 1992 for roughly $215 million, with a further fund earmarked for future fracture claims, while implanted patients carried the device — and the fear — for the rest of their lives.

The Telectronics Accufix — the Pacemaker Wire That Speared Six Hearts

When Telectronics Pacing Systems issued a voluntary worldwide recall of its Accufix atrial “J” pacemaker leads on November 3, 1994 — a recall the U.S. Food and Drug Administration classified as Class I, its most severe category, reserved for products with a reasonable probability of causing serious injury or death — the device had already been doing precisely that. The Accufix lead carried, just behind its J-shaped tip, a thin metal “retention wire” whose only job was to hold the curve that anchored the electrode in the right atrial appendage. That wire fractured from metal fatigue, and the broken end could protrude through the lead’s polyurethane insulation and lacerate the atrial wall, the great vessels, even the aorta. The feature engineered to keep the lead in place became the mechanism that perforated the heart.

The gap between the design intent and the delivered harm was unusually stark because the failure was not rare. Radiographic screening of recalled-population patients found definite retention-wire fracture in 22.4 percent of leads examined, with the incidence climbing toward 25.6 percent on re-evaluation; the multicenter study put the fracture risk at roughly 5.6 percent per year. Roughly 45,000 leads had been implanted worldwide — about 25,000 of them in U.S. patients — across models 330-801 and 329-701. By the time of recall, Telectronics had logged two deaths and two non-fatal injuries; the worldwide registry would eventually record 40 spontaneous injuries, including 19 pericardial tamponades and six deaths.

What made the Accufix case distinct from a simple defective-device story was the trap it set after withdrawal. The lead could not simply be swapped like a battery: it was screwed into beating cardiac tissue and scarred in by years of healing. Extraction was itself lethal — fatal complications occurred in 0.4 percent of intravascular extraction procedures, 16 deaths among 4,023 attempts. Patients and cardiologists faced a documented dilemma with death on both arms: leave a fracturing wire in the heart and accept an annual protrusion risk, or pull it and accept an extraction-mortality risk that, for many low-fracture-risk patients, exceeded the hazard of leaving it alone. Telectronics funded the Accufix Research Institute to run the registry and study that quantified that trade-off, then exited the pacing business; the U.S. litigation consolidated as MDL-1057 and resolved in a settlement establishing a $58 million medical-monitoring and claims fund.