Elsevier

Heart Rhythm

Volume 17, Issue 11, November 2020, Pages 1878-1886
Heart Rhythm

Clinical
Devices
Comparison of left ventricular lead upgrade vs continued medical care among patients eligible for cardiac resynchronization therapy at the time of defibrillator generator replacement: Predictors of left ventricular lead upgrade and associations with long-term outcomes

https://doi.org/10.1016/j.hrthm.2020.05.032Get rights and content

Background

Randomized trials evaluating cardiac resynchronization therapy (CRT) have excluded patients with a pre-existing implantable cardioverter–defibrillator (ICD). The association of CRT upgrade with clinical outcomes in patients with a pre-existing ICD is unclear.

Objective

The purpose of this study was to examine a CRT-eligible population to evaluate clinical outcomes associated with CRT upgrade compared to patients who did not undergo CRT.

Methods

Using the National Cardiovascular Data Registry (NCDR) ICD Registry between April 2010 and December 2014, we created a hierarchical logistic regression model to identify predictors of CRT upgrade in a CRT-eligible ICD population. In the subpopulation of patients with Medicare-linked claims data, differential outcomes were determined with censoring at 3 years. The primary endpoint of this study was all-cause mortality, with secondary endpoints of rates of hospitalization and procedural complications.

Results

CRT upgrade was performed in 75.5% of CRT-eligible patients with pre-existing ICD (n = 15,803). Presence of left bundle branch block conduction was the strongest predictor of CRT upgrade (odds ratio [OR] 4.56; 95% confidence interval [CI] 4.08–5.11; P <.0001). In both unadjusted and adjusted analyses, CRT upgrade was associated with a reduction in mortality at 3 years (unadjusted hazard ratio [HR] 0.80; 95% CI 0.70–0.92; P = .001; adjusted HR 0.84; 95% CI 0.72–0.98; P = .02, respectively). Compared to patients with ICD generator replacement only, patients who underwent CRT upgrade experienced no different 3-year rates of hospitalization (adjusted HR 1.01; 95% CI 0.91–1.12; P = .81) or 1-year periprocedural complication rates (adjusted HR 1.07; 95% CI 0.79–1.45; P = .66).

Conclusion

In a national registry of CRT-eligible patients with pre-existing ICD, upgrade to CRT was associated with lower rates of mortality than continued medical management.

Introduction

Conduction system disease may develop during the clinical course of patients with cardiomyopathies.1 The treatment of these conduction abnormalities along with associated dyssynchrony using cardiac resynchronization therapy (CRT) improves survival, left ventricular (LV) function, and symptoms in subsets of patients with heart failure (HF).2, 3, 4 For those patients who do not qualify for CRT but have persistently depressed LV function, an implantable cardioverter–defibrillator (ICD) provides protection from sudden arrhythmic death.5 Importantly, conduction disease may develop over time, and patients who initially qualify for an ICD without CRT may later develop an indication for resynchronization.6 In these CRT-eligible patients with a pre-existing, non-CRT ICD, clinical decision-making is unclear. Specifically, how do the benefits and risks compare in CRT-eligible patients with a pre-existing ICD who are treated with an LV lead upgrade procedure vs CRT-eligible patients who continue on medical therapy with an ICD generator replacement but without LV lead upgrade.

Published evidence to guide clinical decision-making regarding CRT upgrade in a population with pre-existing ICD is limited. No randomized clinical trials have evaluated whether CRT upgrade confers the same benefits that have been observed with de novo CRT implantation. Furthermore, the major trials evaluating the benefit of CRT specifically excluded patients with a pre-existing device. A registry examined periprocedural morbidity of LV lead upgrade but without a CRT-eligible control population and with little information about long-term outcomes.7 Other studies examined LV lead upgrade outcomes but lacked a comparator group of pre-existing ICD patients who did not undergo CRT upgrade.8,9 By examining the National Cardiovascular Data Registry (NCDR) ICD Registry, a large, real-world population of patients implanted with an ICD, we sought to assess the prevalence and predictors of CRT upgrade in CRT-eligible patients undergoing ICD generator replacement. We also sought to assess the association of CRT upgrade vs continued medical care (ICD generator replacement only) with subsequent clinical outcomes, including procedural complications, rehospitalization, and mortality.

Section snippets

Data sources

Patient data were derived from the American College of Cardiology’s (ACC) NCDR ICD Registry. The NCDR ICD Registry uses a data collection form with standardized data elements and definitions to capture patient demographics, medical history, discharge medication prescription, and other diagnostic study results and adverse events. Longitudinal outcomes (beyond the index hospitalization) were obtained by linking the registry data to Medicare inpatient fee-for-service claims using indirect patient

Results

Between April 1, 2010, through December 31, 2014, a total of 751,791 patients presented for an ICD-related procedure at hospitals in the United States. Of these patients, 165,981 were admitted for elective generator replacement, LV lead upgrade, or device relocation of their non-CRT ICD. Within this group, 18,223 patients were eligible for CRT as defined by LVEF <35%, QRS >120 ms, and NYHA functional class III/IV HF. Patients with a pacemaker (n = 1495), epicardial lead (n = 803), or abdominal

Discussion

In a large, national cohort of patients with a pre-existing ICD, 75.5% of CRT-eligible patients underwent device upgrade with an 11.2% LV lead failure rate. Although younger patients with lower LV ejection fractions and nonischemic cardiomyopathy were more likely to undergo CRT upgrade, the presence of a left bundle branch block was most predictive (OR 4.6; 95% CI 4.1–5.1; P <.0001). CRT upgrade was associated with a long-term reduction in mortality. CRT upgrade did not significantly impact

Conclusion

In a real-world, national registry of CRT-eligible patients with a pre-existing ICD, upgrade to CRT was associated with lower rates of mortality compared to continued medical management with ICD generator replacement only. This reduction in mortality did not come at the clinical cost of increased periprocedural morbidity, although there was no impact on rates of hospitalization that has been observed in many CRT clinical trials. Further trials with randomized populations should be completed to

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Funding sources: This work of Drs Hyman and Marchlinski was supported by the J and J Fund in Electrophysiology. This research was also supported by the American College of Cardiology Foundation’s National Cardiovascular Data Registry (NCDR). Disclosures: Dr Curtis receives salary providing analytic services to the NCDR; and has equity interest in Medtronic. Dr Hsu has received honoraria from Medtronic, Boston Scientific, Abbott, Biotronik, Biosense Webster, Pfizer, and Bristol-Myers Squibb; research grants from Biotronik and Biosense Webster; and has equity in Acutus Medical. Dr Marchlinski has received consulting fees from Abbott, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. Dr Minges receives salary providing analytic services to the NCDR. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

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