Abstract 1481: Endothelial-Dependent Relaxation in Patients Referred for Cardiac Rehabilitation: Role of Medications
There is evidence that cardiac rehabilitation (CR) improves endothelium-dependent relaxation (EDDR) of coronary as well as peripheral arteries in patients with coronary artery disease (CAD). However, it is unclear whether this benefit may be influenced by medications. We prospectively studied 1122 patients referred for CR at the Lancisi Institute for myocardial infarction (MI) and PTCA/stenting, and coronary bypass surgery (CABG) in the period 2004 –2008. Of them, 469 met the inclusion criteria, i.e. age<75 years, EDDR of brachial artery and cardiopulmonary exercise testing (CPET) on entry and at the end of program, no change in medications during CR, completion of the program. They were randomized to receive CR (24 exercise training sessions at 70% peak VO2, nutrition counseling, group education)(group A, n=239) or to receive only nutrition counseling, periodic visits and medications (group B, n=230). Medications were similarly distributed in the 2 groups (A/B: statins 96/92%; BB 80/82%; ACEI 60/62%; ARBs 24/24%;ASA 90/90%; clopidogrel 28/28%). On entry, EDDR was <7% (cutoff value indicating reduced EDDR in our laboratory) in 65% group A patients and 68% group B patients (MI 69/72%, CABG 85/88% A/B, respectively). Peak VO2 was similar on initial evaluation between A and B (18.5(3.1) ml/kg/min vs 17.8(3.3), 0.76). After 8 weeks, EDDR was >7% in 180 group A patients (75%; 8.6(1.7)%), while it was unchanged in 59 patients (25%, P<0.001). In group B, EDDR was >7% only in 38 patients (16.5%), and it was unchanged or worsened in 192 patients. Peak VO2 was significantly improved in group A vs group B (+18% vs +4%, P<0.01). The improvement in EDDR was correlated with peak VO2 change in group A (r=0.65, P<0.001). Multivariate analysis selected exercise training as the strongest independent predictor of EDDR improvement. Medications did not enter in the model.
almost 2/3 of patients referred for CR have abnormal EDDR despite medications;
exercise training is the sole CR component which predicts the improvement in EDDR after CR;
exercise training has no effect on EDDR in 25% of trained patients.