Changes in cardiopulmonary exercise testing variables after surgery for primary mitral regurgitation

AimsDescribe differences in changes in cardiopulmonary exercise testing after surgery for severe primary mitral regurgitation between class I and class II indications for surgery. Methods Prospective observational study of patients who underwent transthoracic echocardiogram and cardiopulmonary exercise testing pre-operatively and six months after surgery. Results Forty three of the fifty patients recruited between February 2017 and October 2018 were included in per protocol analysis. Seven patients were excluded-two patients did not meet inclusion criteria after further investigation, two patients were unable to perform pre-operative cardiopulmonary exercise testing, two patients had post-operative mortality, one patient declined post-operative cardiopulmonary exercise testing. Median age was 64 years and 15 patients (34.9%) were female. Thirty five patients had impaired post-operative functional capacity defined as post-operative left ventricular ejection fraction on echocardiogram <50% and/or post-operative percentage predicted peak VO2 ≤ 84%). In patients with class I indication for surgery (n = 30), there was no significant change post-operatively in ppVO2 (81 (69-88) % vs. 79 (60-87) %, p = 0.09). In patients with class II indication for surgery (n = 13), there was a significant fall post-operatively in ppVO2 (82 (79-92) % vs. (74 (68-86) %, p < 0.01). In the univariate analysis, pre-operative ppVO2 ≤ 84% (p < 0.01) was a predictor for impaired post-operative functional capacity. Conclusions Patients with class I indication have persistently abnormal exercise performance six months after surgery. Patients with class II indication for surgery have worse exercise performance parameters six months after surgery. Pre-operative ppVO2 ≤84% is an independent predictor of impaired post-operative functional capacity at six months.