Cardiac Rehabilitation After Acute Coronary Syndrome: Do All Patients Derive the Same Benefit?

Abstract

INTRODUCTION: Cardiac rehabilitation (CR) has been demonstrated to improve exercise capacity in acute coronary syndrome (ACS), but not all patients derive the same benefit. Careful patient selection is crucial to maximize resources. OBJECTIVE: To identify in a heterogeneous ACS population which patients would benefit the most with CR, in terms of functional capacity (FC), by using cardiopulmonary exercise testing (CPET). METHODS: A retrospective analysis of consecutive ACS patients who underwent CR and CPET was undertaken. CPET was performed at baseline and after 36 sessions of exercise. Peak oxygen uptake (pVO2), percentage of predicted pVO2, minute ventilation/CO2 production (VE/VCO2) slope, VE/VCO2 slope/pVO2 and peak circulatory power (PCP) (pVO2 times peak systolic blood pressure) were assessed in two moments. The differences in pVO2 (ΔpVO2), %pVO2, PCP and exercise test duration were calculated. Patients were classified according to baseline pVO2 (group 1, <20 ml/kg/min vs. group 2, ≥20 ml/kg/min) and left ventricular ejection fraction (group A, <50% vs. group B, ≥50%). RESULTS: We analyzed 129 patients, 86% male, mean age 56.3±9.8 years. Both group 1 (n=31) and group 2 (n=98) showed significant improvement in FC after CR, with a more significant increase in pVO2, in group 1 (ΔpVO2 4.4±7.3 vs. 1.6±5.4; p=0.018). Significant improvement was observed in CPET parameters in group A (n=34) and group B (n=95), particularly in pVO2 and test duration. CONCLUSION: Patients with lower baseline pVO2 (<20 ml/kg/min) presented more significant improvement in FC after CR. CPET which is not routinely used in assessement before CR in context of ACS, could be a valuable tool to identify patients who will benefit the most.