Clinical Effects of Supervised Cardiac Rehabilitation in Patients With Angina and Non-Obstructive Coronary Artery Disease and Impaired Myocardial Flow Reserve Assessed Using 13N-Ammonia Positron Emission Tomography.

Background: The efficacy of exercise-based cardiac rehabilitation (CR) in patients with angina and non-obstructive coronary artery disease (ANOCA) remains unclear. This study investigated whether a multidisciplinary CR program improves myocardial flow reserve (MFR), symptom status, and exercise capacity in patients with ANOCA.

Methods and results: Myocardial blood flow at rest and during ATP-induced hyperemia was quantified using ¹³N-ammonia positron emission tomography (PET) in 29 patients diagnosed with ANOCA and impaired MFR (<2.5). Overall, 16 patients completed the 5-month CR program (complete CR group) and 13 did not (non-complete CR group). At baseline and the 5-month follow-up PET, symptom status and exercise capacity were assessed using the Seattle Angina Questionnaire (SAQ)-7 and cardiopulmonary exercise testing, respectively. The MFR in the complete CR group increased significantly (P=0.001) from a median of 1.60 (interquartile range [IQR] 1.43-1.98) to 2.09 (IQR 1.83-2.48). Significant improvements were also seen in the median SAQ-7 total score (from 16 [IQR 11-20] to 11 [IQR 8-14]; P=0.008) and peak oxygen consumption (V̇O₂; from 14.2 [IQR 12.4-15.8] to 15.3 [13.0-17.9] mL/kg/min; P=0.02). In contrast, there were no improvements in MFR (P=0.83) or peak V̇O₂(P=0.27) in the non-complete CR group.

Conclusions: The 5-month exercise-based CR significantly improved MFR, symptom status, and exercise capacity in patients with ANOCA and impaired MFR.