Elsevier

International Journal of Cardiology

Volume 274, 1 January 2019, Pages 163-169
International Journal of Cardiology

Survival and arrhythmic risk among ischemic and non-ischemic heart failure patients with prophylactic implantable cardioverter defibrillator only therapy: A propensity score-matched analysis

https://doi.org/10.1016/j.ijcard.2018.09.003Get rights and content

Highlights

  • This is the first real-world registry analysing hard endpoints in prophylactic ICD-only HF patients with narrow QRS complex.

  • A propensity-score analysis has never been performed in this clinical setting.

  • All-cause death and arrhythmic risks were similar among ischemic and non-ischemic patients after four years of mean follow-up.

  • The benefit in non-ischemic HF patients might be the same, so ICD therapy should not be restricted to ischemic patients.

  • The decision to implant and ICD must be individualized in patients with more comorbidity.

Abstract

Background

Concerns about the efficacy of prophylactic ICD in non-ischemic cardiomyopathy (NICM) heart failure (HF) patients are still present. We aimed to assess whether survival and arrhythmic risk were different among ischemic cardiomyopathy (ICM) and NICM ICD-only patients, along with specific predictors for mortality.

Methods

HF patients undergoing ICD-only implant were extracted from the nationwide multicenter UMBRELLA registry. Arrhythmic events were collected by remote monitoring and reviewed by a committee of experts.

Results

782 patients (556 ICM; 226 NICM) were recruited: mean ejection fraction of 26.6%; 83.4% in NYHA class II-III; mean QRS duration of 108.9 ms (only 14.9% with QRS > 130 ms). After 4.35 years of mean follow-up, all-cause mortality rate was 4.2%/year. In propensity-score (PS) analysis no survival differences between ICM and NICM subgroups appeared (mortality rates: 19.4% vs. 20%, p = 0.375). Age (hazard ratio [HR] = 1.02, p = 0.009), diabetes (HR = 2.61, p ≤ 0.001), chronic obstructive pulmonary disease (HR = 2.13, p = 0.002), and previous HF (HR = 2.28, p = 0.027) correlated with increased mortality for the entire population, however atrial fibrillation (AF) (HR = 2.68, p = 0.002) and chronic kidney disease (HR = 3.74, p ≤ 0.001) emerged as specific predictors in NICM patients. At follow-up, 134 patients (17.1%) were delivered a first appropriate ICD therapy (5.1%/year) without significant differences between ICM and NICM patients in the PS analysis (17.6% vs. 15.8%, p = 0.968). ICD shocks were associated with a higher mortality (HR = 2.88, p < 0.001) but longer detection windows (HR = 0.57, p = 0.042) correlated with fewer appropriate therapies.

Conclusions

Mortality and arrhythmia free survival is similar among ICM and NICM HF patients undergoing ICD-only implant for primary prevention strategy.

Introduction

Prophylactic implantable cardioverter defibrillator (ICD) is a leading therapy in preventing sudden cardiac death (SCD) in heart failure (HF) patients with impaired left ventricular ejection fraction (LVEF) [1]. Randomized clinical trials (RCTs) have consistently shown that ICD therapy reduces morbidity and mortality as part of primary prevention strategy [[2], [3], [4], [5]]. Nevertheless, concerns about the benefit in non-ischemic HF patients emerged since the first trials, as sudden death from arrhythmia but not all cause mortality was decreased by prophylactic implantation in non-ischemic cardiomyopathy (NICM) patients [3,6]. The discussion arose again, particularly after the publication of the DANISH trial, in which ICD did not significantly decrease the rates of all-cause death in NICM patients, even though SCD was effectively reduced [7]. The addition of cardiac resynchronization therapy (CRT) to an ICD device (58% of patients in both arms of DANISH trial carried CRT devices) not only modifies the possibilities to improve LVEF, especially in non-ischemic candidates, but can also reduce morbidity and mortality outcomes [[8], [9], [10], [11]]. Pooled data from meta-analysis demonstrated, even after elimination of CRT trials, that ICD-only therapy accomplished a reduction in total mortality ranging between 26% and 31% in NICM patients [12,13]. Translation of this evidence into real-world increased the controversy, as several reports suggested that the efficacy of prophylactic ICD for HF patients with reduced LVEF seemed to be similar among RCTs and clinical practice. However, the same problem appeared, as population in these studies is heterogeneous and all of them include patients with wide QRS and high percentages of CRT carriers [[14], [15], [16], [17], [18]].

The present study tries to assess whether survival differs between ischemic and non-ischemic HF patients after ICD implant for primary prevention strategy. We also sought to define the rates of all-cause death and arrhythmia free survival, along with factors to be predictive of both events in a real-life cohort of ICD-only candidates (narrow QRS complex). Finally we try to look for specific predictors of mortality in ischemic and non-ischemic populations.

Section snippets

Patient selection

The present study was developed within the framework of the Scientific Cooperation Platform (SCOOP) supported within the UMBRELLA observational study (ClinicalTrials.gov/NCT01561144), which is a voluntary registry promoted by Medtronic Iberica that includes patients with Medtronic ICDs and follows them by remote monitoring (CareLink®) for both primary and secondary prevention. The institutional review board of the participating centers approved patient inclusion and all patients provided

Patient characteristics

We identified 782 patients in the UMBRELLA database who met the inclusion criteria and none of the exclusion criteria. First ICD implantation was performed from March 2006 until August 2015 in 23 different Spanish hospitals. Ischemic cardiomyopathy (ICM) accounted for 556 patients (71% of total population) while NICM was the etiology in the remaining 226 cases (29%). The baseline clinical characteristics of the overall population and propensity-matched patients are summarized in Table 1. As

Discussion

The present study composed of a nationwide cohort of ICD-only patients focuses on the prognostic role that cardiomyopathy etiology plays regarding all-cause death and arrhythmic risk. All-cause mortality rates among ischemic and non-ischemic HF patients, receiving an ICD for primary prevention, were similar. Predictors of all-cause mortality were age, COPD, DM and previous HF admission, for the entire population, whereas AF and CKD were associated with death only in NICM patients. Moreover,

Conclusions

All-cause death and arrhythmia free survival among ischemic and non-ischemic HF patients undergoing ICD-only implant for primary prevention strategy are similar. Thus the benefit should not be restricted to ischemic patients. Age, DM and COPD strongly predict an increased mortality risk, whereas AF and CKD emerged as specific predictors in NICM patients. Although appropriate ICD therapies were associated with a lower survival, delayed programming appeared as a protective factor.

In HF patients

Disclosures

None of the authors declare any potential conflict of interest.

Funding sources

No funding sources were needed.

Acknowledgments

The authors acknowledge the Spanish Scoop team, especially Alba García, Esther Sastre, and Cristina Álvarez.

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  • Cited by (2)

    • Comparison of Mortality and Readmission in Non-Ischemic Versus Ischemic Cardiomyopathy After Implantable Cardioverter-Defibrillator Implantation

      2020, American Journal of Cardiology
      Citation Excerpt :

      Our results were consistent with those of a recent smaller and more limited study of approximately 5,000 patients (2,181 with NICM and 3,304 with ICM) that found higher mortality in ICM patients that persisted in multivariable analysis (adjusted HR 1.31, CI 1.06 to 1.61, p = 0.01) and after propensity score matching.17 In contrast, a smaller study of 310 propensity-matched patients (556 with ICM and 226 with NICM) found no significant difference in mortality (19.4% vs 20%, p = 0.38),16 but had low statistical power for modest differences. Our study is larger than these previous studies, including 99,052 patients (68,458 ICM and 31,044 NICM) with greater statistical power to detect differences.

    1

    This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.

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