Impact of right ventricular function on cardiac rehabilitation outcomes – insights from the RECOVER-R registry

Background Numerous studies have demonstrated an association between postoperative right ventricular (RV) dysfunction and increased morbidity and mortality. The underlying mechanisms are multifactorial and include ischemia–reperfusion injury, prolonged cardiopulmonary bypass time, myocardial ischemia, as well as volume overload. Despite these insights, evidence regarding the clinical impact of persistent RV dysfunction, particularly during the rehabilitation phase, remains limited. Purpose The aim of our analysis is to investigate the association of reduced RV function on functional parameters, assessed by the 6-minute walk test (6MWT), and on quality of life, assessed with the MacNew Heart questionnaire (MNH), during exercise-based cardiac rehabilitation (EBCR). Methods We retrospectively analysed patients who attended EBCR between 2022 and 2024 at a specialized rehabilitation centre in Switzerland following cardiac surgery. A high proportion of patients (36%) had undergone coronary artery bypass grafting. The median EBCR stay was 20 days (Q1: 20, Q3: 27). Patients were categorized according to RV function assessed by tricuspid annular plane systolic excursion (TAPSE). Treatment outcomes were assessed using 6MWT results and the MNH at admission and discharge. Adjusted linear regression models were used to investigate the possible effect of RV function on the outcomes. Results A total of 865 patients were included (22% female; mean age 64 ± 11 years). At admission, 366 patients (42%) had preserved RV function (mean TAPSE of 19 ± 6 mm), while 499 patients (58%) had reduced RV function (mean TAPSE of 14 ± 2 mm). Although longitudinal RV function was reduced, other parameters of right ventricular function including fractional area change (FAC) and right ventricular systolic pressure (RVSP) were within the normal range and similar between groups (preserved RV function: FAC 46% ± 12, RVSP 23 mmHg ± 9; reduced RV function: FAC 44% ± 12, RVSP 23 mmHg ± 8). Left ventricular ejection fraction was also comparable (preserved RV function: 52% ± 11; reduced RV function: 51% ± 11). The raw median difference in the 6-minute walking distance was significant between the preserved and reduced RV function groups (-27 meters; 95% CI -40 to -15). Results remained significant in a sex and age adjusted model. Among MNH domains, the physical domain showed a significant difference (mean difference 0.13 points; 95% CI 0.01 to 0.25; p = 0.031) as well as the emotional domain (mean difference 0.12 points; 95% CI 0.00 to 0.23; p = 0.05). Conclusion In patients undergoing exercise-based cardiac rehabilitation after cardiac surgery, reduced right ventricular function assessed by TAPSE, was associated with improved functional capacity and a slight improvement in physical quality of life. This may suggest that patients with impaired RV function could particularly benefit from EBCR in the short term.