Outcomes following implantable cardioverter–defibrillator generator replacement in adults: A systematic review

Randomized trials inform the use of implantable cardioverter–defibrillators (ICDs) for prevention of sudden cardiac death, yet management of patients considering ICD generator replacement procedures remains largely dependent on clinical judgment. Thus, we performed a systematic review of all studies evaluating outcomes associated with ICD generator replacement. We queried PubMed, Embase, Web of Science, and the Cochrane Database of Systematic Reviews for relevant studies with a prespecified search and adjudication strategy (PROSPERO registration number CRD42018100818) to evaluate outcomes including (1) survival; (2) clinical complications (eg, infection, hematoma); or (3) incidence of ICD therapy. From 1607 unique titles, 37 studies met inclusion criteria, describing outcomes for 238,949 patients. Procedural mortality was rare, but complications including reoperation (median 4.57%; range 0.38%–10.31%), infections (median 2.01%; range 0.03%–9.27%), and hematoma (median 1.22%, range 0.17%–2.53%) were observed in a small fraction of patients. Appropriate ICD therapy after generator replacement was common (median rate 23.03%; range 10.9%–31.4%), with an overall annualized event rate of 8.52% at median duration of follow-up of 32.4 months. Appropriate ICD therapy continued to occur at a significant annual rate even in patients who no longer met implantation criteria (5.27%) and in patients who never previously received ICD therapy (4.87%). This analysis of published observational data regarding ICD generator replacement procedures identifies relatively low risks of procedural complications and clinically meaningful rates of appropriate ICD therapies. These estimates may guide clinical decisions and inform the design of definitive trials.