Vascular Response to a Cardiac Rehabilitation Program Adapted for COVID-19

ABSTRACT

Background: Cardiac Rehabilitation (CR) is a supervised exercise and risk factor modification program for patients with cardiac conditions. Endothelial dysfunction is often present and is associated with worsening cardiac prognosis, and several studies have indicated that standard onsite CR has improved endothelial function in heart disease patients. However, during the COVID-19 pandemic, many CR programs transitioned to a virtual or hybrid model of care to increase safety of CR programs. Objective(s) The objective of this study was to determine vascular function of patients with coronary artery disease (CAD) measured before and after 4 months of outpatient CR using a virtual model of care. Method(s) Virtual CR included 1 virtual group session/week by videoconferencing and hybrid CR included 1 session/week (4 on-site and 12 virtual group sessions) for a total of 16 weeks. CAD patients (6 females, 4 males) mean age 68.1+/-7.5 years rested in a supine position to measure 1) brachial artery flow-mediated dilation (FMD), 2) microvascular function, and 3) augmentation index (AI) using ultrasound sonography (n=8) and an EndoPAT 2000 (n=9). Two patients completed virtual CR and the rest underwent hybrid CR. These measurements were obtained concurrently using an ultrasound transducer at the brachial artery proximal to a blood pressure cuff on the forearm with EndoPAT cuffs on the index fingers during 5-minute intervals of baseline, occlusion, and recovery. FMD results were analyzed using automated Cardiovascular Suite software. AI and Reactive Hyperemia Index (LnRHI) were determined using automatic analysis via the EndoPAT 2000. Anthropometrics, blood pressure, and food intake were recorded at each visit. Patients were advised to refrain from strenuous exercise, alcohol, caffeine, and highly saturated foods at least 12 hours prior to the study appointment. One tailed paired t-tests were conducted between baseline and completion. Result(s) Adherence to CR averaged 10.3+/-3.2 out of 16 sessions. FMD improved from (2.75+/-1.71% to 5.63+/-4.37%, p=0.048) while there was no improvement in AI (14.2+/-18.8 to 13.2+/-19.6, p=0.45) or LnRHI (0.56+/-0.12 to 0.52+/-0.20, p=0.24). Conclusion(s) While there was no improvement in LnRHI or AI after CR, FMD improved in CAD patients after 4 months of adapted CR. Our results indicate that while virtual and hybrid models of CR may not be sufficient for improving microvascular function and aortic stiffness in CAD, there is an improvement of endothelial function. Future studies should examine the effects of adherence, duration and exercise intensity within these alternative models of CR on aortic and microvascular improvements.