Cardiac rehabilitation in patients with refractory angina trial: rationale and design (Preprint)

BACKGROUND Refractory angina is a chronic condition that implies significant impairment in quality of life; its management is a challenge. Current therapies are limited, and new approaches to treatment are needed that target symptoms and quality of life. Evidence is lacking regarding exercise-based cardiac rehabilitation safety and beneficial effects in patients with refractory angina. OBJECTIVE The aim of the present study is to evaluate the safety and feasibility of exercise-based cardiac rehabilitation in patients with refractory angina, and its effects on angina symptoms, functional capacity, and ischemic burden. METHODS This study is an ongoing prospective randomized controlled trial enrolling 52 patients with refractory angina randomized into 2 groups: optimal medical treatment (MT) or MT + exercise-based cardiac rehabilitation (CR) over 12 weeks (36 exercise sessions). Clinical evaluation, cardiopulmonary exercise testing, laboratory tests, and exercise echocardiography are performed before and after intervention. The CR group performs in-hospital exercise sessions. The aerobic training protocol is based on CPT parameters or ischemia/angina threshold. Each cardiac rehabilitation session is 60 minutes long (5 minutes of warm-up, 30 minutes of continuous aerobic exercise based on target heart rate corresponding to anaerobic threshold (AT) obtained in the cardiopulmonary exercise testing OR angina/ischemia threshold if it occurs before the AT, 5 minutes of cooling-down, 15 minutes of resistance training, and 5 minutes of stretching). RESULTS This research study is in progress, with 42 patients recruited as of August 2019. Data collection is expected to be finished before December 2020. No clinical adverse events related to CR have occurred. CONCLUSIONS The findings of this study will have important clinical implications in the treatment of refractory angina patients. CLINICALTRIAL NCT03218891