Impact of right ventricular function on cardiopulmonary exercise capacity in mitral regurgitation patients undergoing transcatheter mitral valve intervention.

Objective: Transcatheter mitral valve interventions (TMVI) have been proven to reduce symptom burden and improve outcomes in patients with severe mitral regurgitation (MR). However, the impact of right ventricular function (RVF) on exercise capacity in MR patients is less well understood.

Methods: Cardiopulmonary exercise testing (CPET) is the most comprehensive approach to assess maximum exercise capacity. Submaximal exercise capacity (SEC), assessed by constant work rate exercise time testing (CWRET), is presumed to be relevant in daily life activities and gives a more differentiated physiological insight into the nature of exercise intolerance. Thus, 28 MR patients underwent CPET and CWRET (at 75% of the maximum work rate in the initial incremental exercise test) prior to TMVI and 3 months post-procedurally.

Results: Patients' mean age was 75.0 ± 8.7 years and 32.1% were female. One patient presented with an MR reduction of less than two grades. RVF was at least moderately impaired in 25% of the patients. SEC of these patients was lower but did not significantly differ (416.4s ± 359.6 vs. 296.1 ± 216.5s; p=) from patients without RVF-deterioration. At follow-up, the SEC improved significantly (from 337.4 ± 262.2s to 517.4 ± 393.5s; p = 0.006). Maximum oxygen uptake (peakVO₂) showed a positive trend, but no statistically significant difference (10.3 ± 3.1 ml/min/kg vs. 11.3 ± 3.4 ml/min/kg; p = 0.06). RVF improved in 35.7% of the patients and these patients showed a significantly higher SEC increase (471.7 ± 153.9s vs. 82.7 ± 47.0s, p = 0.003).

Conclusion: SEC is significantly increased in MR patients undergoing TMVI, reflecting an improvement, especially regarding daily life activities. This may be related to TMVIś beneficial effect on right ventricular remodeling.