This month's Medtronic defibrillator Sprint Fidelis lead recall has prompted Congress to initiate of review of the procedures the Food & Drug Administration (FDA) uses to test heart device components. The review is being undertaken by the House of Representatives Committee on Oversight and Government Reform, which sent a letter to the FDA asking officials there a series of questions about the agency's oversight of defibrillator leads.
Medtronic suspended sales and recalled all unused Sprint Fidelis leads last Monday, 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 defective Sprint Fidelis leads are being told to leave the components in place unless they fracture.
When it issued the Sprint Fidelis lead recall, Medtronic estimated that about 2.3%, or 4,000 to 5,000 people with a Sprint Fidelis lead will experience fracture within 30 months of having a defibrillator implanted. Apparently, it was a problem that the company had known about for months.
Since it was introduced to the market in 2004, there have been 599 reports of lead fractures as of January 2007. And it seems as though the fracture problems became worse over time. In the first two months of 2006, there were 27 reports of the Sprint Fidelis lead fracturing. But in the first two months of 2007, there were 152 reports. And since January 10, 2007, there have been a staggering 1,030 reports of fractures.
Shortly after the Sprint Fidelis lead recall, it was learned that the FDA had not required extensive testing of the vital defibrillator component before it went on the market. Although the agency had required Medtronic to test an earlier version of a defibrillator lead in patients before approval, it had not required the company to do so for the defective Sprint Fidelis lead.
That was because officials at the FDA had determined that the Sprint Fidelis lead was not a significant enough change from the design of its predecessor. Instead, the FDA required the Sprint Fidelis lead to pass only tests intended to identify design flaws. Those were principally mechanical stress tests meant to recreate the pressures in the body. The FDA is trying to figure out why those tests did not pick up the defects in the Sprint Fidelis lead.
Some medical experts have questioned the FDA's decision not to put the defective Sprint Fidelis lead through more clinical tests. Though its predecessor, the Sprint Quattro, has a good performance history, the Sprint Fidelis lead is a significantly thinner wire. Many believe that thinness made the defective Sprint Fidelis lead more apt to fracture.
The issues that the Congressional Committee is investigating include the FDA's decision not to subject the defective Sprint Fidelis lead to more rigorous testing, and why all defibrillator leads are not subject to the same level of scrutiny as the heart devices themselves.