Rev Port Cardiol. 2017 Feb 23
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