When Implanted Heart Devices Fail
The Odds -- and Consequences -- of Pacemaker, ICD Breakdowns
ICD Replacement Risks continued...
"We were surprised by the high risk of infection and the number of replacement procedures that required a second operation," Krahn says. "We reported a 6% major complication rate. And 2% of patients with major complications required a major surgical procedure. That is a compelling risk. Our concern about the device has to cap that threshold for us to advocate replacing it."
So what should you do if you've received an "advisory" warning that your ICD might fail? This is a tough question, and the answer may be not to have the device removed.
"The majority of advisories had a 1-in-10,000 to a 1-in-100 risk of device failure," Krahn says. "And for some manufacturer advisories, you can detect problems by monitoring the device. So the vast majority of the time, you detect a problem before the patient feels anything. On the other hand, some advisories warn of abrupt loss of function. Some patients suffer sudden death."
It's an unusual risk-vs.-benefit decision. Patients, Krahn says, should first look at their own medical condition, then at the risk estimated for the specific device they have implanted.
"Let's say a man had a first heart attackheart attack three years ago, and the doctor advised him that his risk of sudden death is 2% to 5% per year," Krahn says. "If that patient has device put in and finds out there is a 1-in-1,000 chance the device will not be reliable, the patient may say leave that alone. If, on the other hand, that patient received a shock three months ago, and the doctor says, 'We checked the device, it saved your life,' then the patient may want a new one, because his life clearly depends on it working."
Wilkoff agrees that patients must carefully consider whether to replace an ICD because of an advisory.
"It turns out that changing the device is not necessarily the lower-risk answer," he says. "We shouldn't overreact to the realization these remarkably effective devices aren't perfect. Maisel found a 1%-2% malfunction rate, not death risk. But in the ICD population, there is a 7% to 15% annual risk of death without a device. Is the ICD perfect? No. But we cannot have people panicking about this when there are much bigger devils sitting outside their doors."