Background/Objectives

To investigate the role of right ventricular function on exercise capacity in patients undergoing transcatheter mitral valve repair (TMVR) we aimed to perform cardiopulmonary exercise testing and to show a correlation between an improved right heart function and maximal and submaximal exercise capacity.

Methods

Constant work rate exercise time testing (CWRET) reflects submaximal / endurance exercise capacity, which is more likely to be relevant for daily life activities, and gives a more differentiated physiologic insight into the nature of exercise intolerance. Thus, 28 Patients with mitral regurgitation and symptomatic heart failure (NYHA ≥ II) underwent cardiopulmonary exercise testing by assessment of maximal oxygen uptake (peak VO₂) and submaximal exercise capacity (at 75% of maximal achieved work rate in the initial incremental exercise test) accompanied by echocardiography prior to TMVR and 3 months post-procedure.

Results

Mean age of the patients was 75.0 ± 8.7 years and 32.1% of them were female. Technical success could be achieved in all cases. One patient presented a reduction of mitral regurgitation less than 2 grades. Right ventricular function (assessed with right ventricular area fraction, tricuspid annular plane systolic excursion, longitudinal strain of the right ventricular free wall and S`) was at least moderately impaired in 25% of the patients. The submaximal exercise capacity of these patients was impaired, but did not significantly differ (416.4 sec ± 359.6 vs. 296.1 ±216.5 sec) compared to patients without a deterioration in right ventricular function.

Three months after intervention, exercise time at 75% of maximal achieved work rate significantly improved (from 337.4 ± 262.2 sec to 517.4 ± 393.5 sec p=0.006), reflecting a gain in submaximal exercise tolerance. Maximal oxygen uptake (peak VO₂) 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=0.056).

Right ventricular function (at least 2 of 4 parameters) improved in 35.7% and these patients showed a significantly higher submaximal exercise time increasement (471.7 ± 153.9 sec vs. 82.7 ±47.0 sec, p=0.003).

Discussion/Conclusion

Transcatheter mitral valve repair may have a beneficial effect on right ventricular remodeling. Furthermore, submaximal exercise capacity is significantly increased, reflecting an improvement especially regarding daily life activities in mitral regurgitation patients and impaired right ventricular function.