136-37: Health-related quality-of-life in patients with leadless pacemaker


Purpose: Leadless pacemakers (LPs) are miniaturized, fully self-contained devices percutaneously implanted in the right ventricle using a femoral vein approach. The multicenter LEADLESS II clinical trial has demonstrated that both pre-specified safety and effectiveness endpoints for the NanostimTM LP were met. This study assessed the health-related quality-of-life (HRQoL) in these LP patients and its corresponding changes over time.

Method: Patients' HRQoL were assessed using the EuroQol EQ-5D, a preference-based instrument from which utility values could be generated on the basis of item responses and an established EuroQol algorithm. EQ-5D utilities were measured on a cardinal scale of 0–1, where 0 indicates death and 1 indicates full health; with higher utilities representing better HRQoL. We included the 468 patients from the LP IDE Study who had complete EQ-5D item responses at 4 time points including: pre-discharge, weeks 2, 6 and 12, respectively. Patients' baseline EQ-5D utilities (before the LP implant) were not collected; hence, a systematic review of US single-chamber pacemaker studies was conducted to obtain the mean baseline utility value to be used as the reference point for comparison. Proportional changes in EQ-5D utilities at different time points, compared with the baseline utility, were estimated and tested using Analysis of Variance. Effect sizes were calculated to evaluate the magnitude of these changes, independent of sample size effects.

Summary: Mean patient age was 75 (±12) years, 37% were female and 91% were white. As shown in Table 1, mean baseline EQ-5D utility, based on literature review, was 0.73. Mean EQ-5D utility at pre-discharge was 0.81, and increased to 0.84, 0.85 and 0.84 at weeks 2, 6, and 12, respectively (p < 0.01). Compared with the baseline utility, the EQ-5D utility increased by 10.3% at pre-discharge, then by 14.7%, 16.7% and 14.7% at weeks 2, 6 and 12, respectively (p < 0.01). A moderate to high effect size of 0.55 was achieved at week 2, followed by a sustained improvement over the 12-week period (Table 1). Table 1.

EQ-5D utility values and changes over time Mean SD Utility Change
(%, compared with baseline) Effect Size¥
(compared with baseline) Baseline* 0.7300 Pre-discharge 0.8053 0.2219 10.31%§ 0.3393 Week 2 0.8375 0.1964 14.73%§ 0.5476 Week 6 0.8522 0.1833 16.73%§ 0.6666 Week 12 0.8375 0.1781 14.73%§ 0.6038 *

Baseline utility was obtained from a systematic review of single-chamber pacemaker studies in the US, which was 0.73. ¥

Effect size (ES) measures the magnitude of the utility changes, independent of sample size effect, where: ES ≥ 0.8: large effect; 0.8 ≥ ES ≥ 0.5: moderate to high effect; 0.5 ≥ ES ≥ 0.2: low to moderate effect; ES ≤ 0.2: low effect. §

All % utility changes were statistically significant, compared with baseline utility.

Conclusions: These data indicate that implantation of the NanostimTM LP is accompanied with improved HRQoL immediately after implant and the improvement was sustained over time.

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