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Predictors of short-term complications after ICD replacement: results from the Ontario ICD database


Background — Complications after ICD replacement are often clinically devastating, particularly when infection or reoperation occurs. Identifying factors contributing to complications may permit identification of high-risk individuals that warrant incremental monitoring and therapy to attenuate risk. In addition, replacement may be a discretionary decision in the context of an advisory or borderline device performance, and patient, device and implanter factors that predict adverse outcome may assist in clinical decision-making.

Methods and Results — In a prospective, multicenter, population-based registry of all implantable cardioverter defibrillator (ICD) patients at 18 centers in Ontario, Canada, the authors examined 45-day complication and all-cause mortality rates from February 2007 to August 2009 in patients undergoing ICD generator replacement. Complications were determined longitudinally and were categorized as major or minor. ICD replacement was performed in 1,081 of 5,176 patients (20.8%) undergoing ICD implantation (age 64.3 ± 12.7 years, 78.5% men). In patients undergoing ICD replacement, 47 patients (4.3%) experienced a complication within 45 days, with 47 major complications in 28 patients (2.6%), most commonly infection (n=23), lead revision (n=35), electrical storm (n=14) and pulmonary edema (n=13). Minor complications occurred in 2.3% of patients, most commonlyincisional infection (n=10) and pocket hematoma (n=10). On multivariable analysis, risk factors associated with major complications were CCS angina class (adjusted HR 3.70 for class 2-4 vs. 0-1, p=0.027) and multiple previous procedures on the pocket (adjusted HR 3.35 for >1 vs. 1, p=0.058). Risk factors associated with any complication were the use of antiarrhythmic therapy (adjusted HR 6.29, p=0.001), implanter volume (adjusted HR 10.4 for <60/year vs. >120/year, p=0.026) and CCS angina class (adjusted HR 3.00 for class 2-4 vs. 0-1, p=0.031). In a Cox model with a time-dependent variable of major complication within 45 days after replacement, major complications after ICD replacement were associated with an increased risk of mortality at 45, 90 and 180 days (adjusted HR 9.61, 12.69 and 6.41 respectively, p=0.002–0.039).

Conclusions — Risk factors associated with complications after ICD replacement include the presence of angina, antiarrhythmic therapy, increased number of previous procedures and low implanter volume. Major complications may be associated with increased risk of subsequent mortality.



Krahn AD, Lee DS, Birnie D, Healey JS, Crystal E, Dorian P, Simpson CS, Khaykin Y, Cameron D, Janmohamed A, Yee R, Austin PC, Chen Z, Hardy J, Tu JV; Ontario ICD Database Investigators. Circ Arrhythm Electrophysiol. 2011; 4(2):136-42. Epub 2011 Feb 15.

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