1. In this comparative efficacy study using administrative claims data, patients who received a leadless pacemaker had higher rates of pericardial effusion and perforation within 30 days but lower device-related complication rates and requirements for device modifications at 6 months.
2. Additional studies are required to develop the evidence on long-term impact and clinical benefits of leadless technology to help guide clinical decision-making on choice of pacemaker device among various patient populations.
Evidence Rating Level: 2 (Good)
Study Rundown: Since approval from the US Food and Drug Administration in 2016, leadless pacemakers have established their safety and efficacy through numerous clinical trials, demonstrating a marked reduction in complications related to transvenous pacing leads and subcutaneous pockets – the most common sources of complications related to conventional transvenous pacemakers. Despite this, the comparative performance of leadless VVI (ventricular demand pacing) technology vs transvenous devices has not been validated in a large patient population. This continuously enrolling observational cohort study, Micra CED, sought to compare the safety and complication rates of patients treated with leadless VVI pacemakers with a contemporary cohort of patients treated with transvenous VVI pacemakers in the Medicare setting. The main endpoints and measures of the analysis were acute (30-day) complications and 6-month complications. Among 15,408 patients enrolled, those who received a leadless pacemaker were observed to have higher rates of pericardial effusion and/or perforation but lower rates of other device-related acute and 6-months complications even after adjusting for significant differences in patient characteristics. In this novel post-market comparative efficacy study, the findings suggested that patients who received a leadless pacemaker were observed to have higher rates of pericardial effusion and/or perforation within 30 days but lower device-related complication rates and requirements for device modifications at 6 months. Further studies are required to develop the evidence on long-term impact and clinical benefits of leadless technology to help guide clinical decision-making on choice of pacemaker device among various patient populations. A limitation of this study was that due to the inherent nonrandomized observational nature and reliance on administrative claims data, certain complications and their characteristics important to risk stratification may have been omitted or inadequately documented including complications without specific diagnosis codes and qualitative data on complications (e.g., complexity and severity).
In-Depth [prospective cohort]: This continuously enrolling observational cohort study, the Longitudinal Coverage With Evidence Development Study on Micra Leadless Pacemakers (Micra CED), enrolled 15,408 patients from the US Medicare fee-for-service population between March 2017 and December 2018 (mean [SD] age, 81.0 [8.7] years; 6,701 [43.5%] females). Data analysis was completed from May 2018 to April 2021. Inclusion criteria included Medicare patients implanted with leadless and transvenous VVI pacemakers and exclusion criteria included patients with less than 12 months of continuous enrollment in Medicare before pacemaker implantation and with evidence of a prior cardiovascular implantable device. Among patients, 5,746 patients were implanted with leadless VVI pacemakers and 9,662 with transvenous VVI pacemakers. Compared to patients who received transvenous pacemakers, those with leadless pacemakers were more likely to have end-stage kidney disease (690 [12.0%] vs 226 [2.3%]; P < .001) and a higher mean (SD) Charlson Comorbidity Index score (5.1 [3.4] vs 4.6 [3.0]; P < .001). Compared to patients with transvenous pacemakers, those with leadless pacemakers had a higher unadjusted acute complication rate (484/5,746 [8.4%] vs 707/9,662 [7.3%]; P = .02), statically nonsignificant after adjusting for patient characteristics (7.7% vs 7.4%; risk difference, 0.3; 95%CI, -0.6 to 1.3; P = .49). Specifically, pericardial effusion and/or perforation within 30 days was significantly higher among patients with leadless pacemakers than those with transvenous pacemakers for both unadjusted and adjusted models (unadjusted, 47/5,746 [0.8%] vs 38/9,662 [0.4%]; P < .001; adjusted, 0.8% vs 0.4%; risk difference, 0.4; 95%CI, 0.1-0.7; P = .004). Lastly, patients with leadless pacemakers had a lower rate of 6-month complications than those with transvenous pacemakers (unadjusted HR, 0.84; 95%CI, 0.68-1.03; P = .10; adjusted HR, 0.77; 95%CI, 0.62-0.96; P = .02).
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