(P196) PREDICTORS OF MITRAL VALVE HEMODYNAMICS AFTER MITRAL VALVE REPAIR FOR DEGENERATIVE MITRAL REGURGITATION: A SUBANALYSIS OF THE CAMRA RANDOMIZED TRIAL

Background: Intra-operative predictors of mid-to-late mitral valve dysfunction after surgical repair of mitral regurgitation caused by prolapse remain poorly characterized. This study aims to evaluate the effect of annuloplasty prosthesis size on post-operative mitral valve (MV) hemodynamics at rest and during exercise, and to identify perioperative predictors of MV dysfunction.

METHODS AND RESULTS: 104 patients were randomly assigned to resection or preservation for surgical treatment of posterior leaflet prolapse in the Canadian Mitral Research Alliance CardioLink-2 study. Echocardiograms were performed at baseline and 1-year postoperatively. Intraoperative transesophageal echocardiography was performed to assess immediate MV gradients. Exercise transthoracic echocardiography was performed 1-year after repair. Linear regression analysis was used to identify associations between MV indices (rest and peak exercise gradients) at 12 months, and perioperative echocardiographic and clinical factors. Mean age of participants was 65±10 years, and 83% were male. Larger annuloplasty size was associated with lower transmitral gradients at rest and during peak exercise. In multivariable analysis, annuloplasty size≥34mm was associated with lower mean and peak rest and exercise gradients at 12 months, after adjustment for repair type, age, sex, and BSA. Higher pre-operative pulmonary artery pressures were associated with reduced functional capacity post-operatively. Intra-operative TEE gradients predicted resting and exercise MV hemodynamics at follow-up.

Conclusion: Annuloplasty size >=34mm is associated with improved MV hemodynamics at rest and during peak exercise 1 year post MV repair. MV repair prior to onset of pulmonary hypertension confers favourable post-operative functional capacity. Finally, intra-operative TEE predicts MV dysfunction within 1 year post-repair.