A number of patients experience complications after implantable cardioverter-defibrillation (ICD) replacement and more often than not these complications can be debilitating and linked to an increased risk of mortality, according to the results from the Ontario ICD database published in the April issue of Circulation: Arrhythmia and Electrophysiology.

The authors noted ICD complications, particularly infections or reoperations, are harmful to patients and said that “identifying factors contributing to complications may permit identification of high-risk individuals that warrant incremental monitoring and therapy to attenuate risk.”

To gain a better understanding of why these types of complications occur and how to prevent them, Andrew D. Krahn, MD, of the London Health Sciences Centre in London, Ontario, and colleagues evaluated a multicenter registry that included information of ICD patients at 18 centers in Ontario.

The researchers examined 45-day complication rates (major and minor) and all-cause mortality rates in patients undergoing ICD generator replacement between February 2007 and August 2009.

ICD replacement was performed in 1,081 of the total 5,176 patients undergoing ICD implantation. Patients had a median age of 64.3 years, and 78.5 percent were men.

Krahn et al reported that 4.3 percent of the patients undergoing ICD replacement experienced a complication within 45 days. There were 47 major complications in 28 patients, with the majority linked to infection, lead revision, electoral storm and pulmonary edema. Severity of angina and the number of device surgeries were two independent risk factors for major complications.

Minor complications occurred in 2.3 percent of patients, and the majority were due to incision infection and pocket hematoma. These complications were independently associated with antiarrhythmic drugs and low operator procedural volumes.

Additionally, the researchers noted that major complications after an ICD replacement procedure were linked to an increased risk of mortality at 45, 90 and 180 days. Mechanical complications directly related to the ICD procedure were related to a 4.4 percent, 8.7 percent and 8.7 percent rate of mortality at 45, 90 and 180 days.

For those who did not experience a major mechanical complication, mortality rates were 0.66 percent, 0.95 percent and 1.8 percent, respectively.

“Clinicians and researchers should consider strategies to minimize the need for device replacement, particularly because most devices are implanted for primary prevention,” the authors wrote.

The researchers noted that evaluation of Medicare administrative databases showed that 14.2 percent of patients experienced complications within 90 days of device procedure. In addition, another study evaluating complications in Medicare beneficiaries showed that 10.8 percent of ICD recipients experienced a complication that also amplified costs and increased length of stay.

“The [current] finding of clustering of multiple complications in individual patients is interesting, suggesting that patients who have had a complication may have more than one complication from some primary trigger or that their underlying comorbidities place them at high risk of simultaneous or successive complications,” the authors noted.

“Complications occurred in a significant proportion of patients undergoing ICD replacement,” the authors concluded. “Risk factors for complications after ICD replacement include the presence of angina, low implanter procedural volume, the number of repeated procedures and antiarrhythmic therapy.”

The current study concluded that complications often stem from the device, physician or patient factors.