Cardiac index: A superior parameter of cardiac function than left ventricular ejection fraction in risk stratification of hypertrophic cardiomyopathy
- PMID: 36870381
- DOI: 10.1016/j.hrthm.2023.02.028
Cardiac index: A superior parameter of cardiac function than left ventricular ejection fraction in risk stratification of hypertrophic cardiomyopathy
Abstract
Background: An appropriate indicator of cardiac function in the risk stratification of hypertrophic cardiomyopathy (HCM) patients is urgently needed. Cardiac index that reflects cardiac pumping function may be suitable.
Objective: The purpose of this study was to investigate the clinical significance of reduced cardiac index in HCM patients.
Methods: A total of 927 HCM patients were enrolled. The primary endpoint was cardiovascular death. The secondary endpoints were sudden cardiac death (SCD) and all-cause death. Combination models were constructed by adding reduced cardiac index and reduced left ventricular ejection fraction (LVEF) to the HCM risk-SCD model. Predictive accuracy was determined by C-statistics.
Results: Reduced cardiac index was defined as cardiac index ≤2.42 L/min/m2. During median follow-up of 4.3 years, 51 patients reached the endpoint. Reduced cardiac index independently increased the risk of cardiovascular death (adjusted hazard ratio [aHR] 2.976; P = .007), SCD (aHR 6.385; P = .001), and all-cause death (aHR 2.428; P = .010). By adding reduced cardiac index to the HCM risk-SCD model, the model C-statistic increased from 0.691 to 0.762, with an integrated discrimination improvement of 0.021 (P = .018) and a net reclassification improvement of 0.560 (P = .007). The addition of reduced LVEF failed to improve the original model. Better predictive accuracy for all endpoints was also indicated in reduced cardiac index than in reduced LVEF.
Conclusion: Reduced cardiac index is an independent predictor of poor prognoses in HCM patients. Combining reduced cardiac index rather than reduced LVEF improved the HCM risk-SCD stratification strategy. The reduced cardiac index showed better predictive accuracy than reduced LVEF for all endpoints.
Keywords: Cardiac index; Hypertrophic cardiomyopathy; Left ventricular ejection fraction; Risk stratification; Sudden cardiac death.
Copyright © 2023 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.
Comment in
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Cardiac magnetic resonance imaging continues as a cornerstone of the assessment of hypertrophic cardiomyopathy.Heart Rhythm. 2023 Jul;20(7):968-969. doi: 10.1016/j.hrthm.2023.04.002. Epub 2023 Apr 10. Heart Rhythm. 2023. PMID: 37044291 No abstract available.