Comparative study of acute and mid-term complications with leadless and transvenous cardiac pacemakers

BACKGROUND Leadless cardiac pacemakers (LCPs) aim to mitigate lead- and pocket-related complications seen with transvenous pacemakers (TVPs). OBJECTIVE The purpose of this study was to compare complications between the LCP cohort from the LEADLESS Pacemaker IDE Study (Leadless II) trial and a propensity score-matched realworld TVP cohort. METHODS The multicenter LEADLESS II trial evaluated the safety and efficacy of the Nanostim LCP (Abbott, Abbott Park, IL) using structured follow-up, with serious adverse device effects independently adjudicated. TVP data were obtained from Truven Health MarketScan claims databases for patients implanted with single-chamber TVPs between April 1, 2010 and March 31, 2014 and more than 1 year of preimplant enrollment data. Comorbidities and complications were identified via International Classification of Diseases, Ninth Revision and Current Procedural Terminology codes. Short-term (<= 1 months) and mid-term (>1-18 months) complications were compared between the LCP cohort and a propensity score-matched subset of the TVP cohort. RESULTS Among 718 patients with LCPs (mean age 75.6 +/- 11.9 years; 62% men) and 1436 patients with TVPs (mean age 76.1 +/- 12.3 years; 63% men), patients with LCPs experienced fewer complications (hazard ratio 0.44; 95% confidence interval 0.32-0.60; P < .001), including short-term (5.8% vs 9.4%; P = .01) and mid-term (0.56% vs 4.9%; P < .001) events. In the short-term time frame, patients with LCPs had more pericardial effusions (1.53% vs 0.35%; P = .005); similar rates of vascular events (1.11% vs 0.42%; P = .085), dislodgments (0.97% vs 1.39%; P = .54), and generator complications (0.70% vs 0.28%; P = .17); and no thoracic trauma compared to patients with TVPs (rate of thoracic trauma 3.27%). In short- and mid-term time frames, TVP events absent from the LCP group included lead-related, pocket-related, and infectious complications. CONCLUSION Patients with LCPs experienced fewer overall short- and mid-term complications, including infectious and lead- and pocket-related events, but more pericardial effusions, which were uncommon but serious.