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

Abstract

Aims

Describe 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.