Differences in cardiorespiratory fitness improvement following phase II cardiac rehabilitation program among post-coronary artery bypass grafting patients with varied risk factor profiles

Background: This study aims to assess differences in cardiorespiratory fitness improvement after phase II cardiac rehabilitation in coronary artery bypass grafting patients with various risk factor profiles and to investigate their correlation. Methods: Between October 2023 and March 2024, a total of 45 patients (35 males, 10 females; mean age: 59.5±8.5 years; range, 55 to 64 years) who underwent phase II cardiac rehabilitation following coronary artery bypass grafting were retrospectively analyzed. Obesity, hypertension, diabetes mellitus, and dyslipidemia were assessed. The patients were classified according to the specific risk factors and risk factor count. Cardiorespiratory fitness parameters including 6-minute walk distance, maximal oxygen consumption, and metabolic equivalents before and after cardiac rehabilitation were recorded. Results: The average risk factor count was 2.3 per patient, with dyslipidemia most prevalent (73.3%). The highest improvement in cardiorespiratory fitness was shown in patients with four risk factors and those who had obesity. A significant improvement in the cardiorespiratory fitness was observed in all patients, groups with one to four risk factors, and all specific risk factor groups (p<0.05). Patients with obesity showed significantly greater cardiorespiratory fitness improvement, compared to non-obese patients (p=0.009). There was no significant correlation between risk factor count and cardiorespiratory fitness improvement (p>0.05). Conclusion: Cardiac rehabilitation significantly improved cardiorespiratory fitness in all post-coronary artery bypass grafting patients, regardless of risk factor profiles, with notably greater improvements observed in patients with obesity. Clinically, these findings underscore the importance of universally recommending phase II cardiac rehabilitation in this patient group, particularly emphasizing tailored interventions in individuals with obesity to maximize rehabilitation outcomes and potentially reduce cardiovascular morbidity and mortality.