Survival loss linked to guideline-based indications for degenerative mitral regurgitation surgery

Aims: Operating on patients with severe degenerative mitral regurgitation (DMR) is based on ACC/AHA or ESC/EACTS guidelines. Doubts persist on best surgical indications and their potential association with postoperative survival loss. We sought to investigate whether guideline-based indications lead to late postoperative survival loss in DMR patients.

Methods and results: We analysed outcome of 2833 patients from the Mitral Regurgitation International Database registry undergoing surgical correction of DMR. Patients were stratified by surgical indications: Class I trigger (symptoms, left ventricular end-systolic diameter ≥ 40 mm, or left ventricular ejection fraction < 60%, n = 1677), isolated Class IIa trigger [atrial fibrillation (AF), pulmonary hypertension (PH), or left atrial diameter ≥ 55 mm, n = 568], or no trigger (n = 588). Postoperative survival was compared after matching for clinical differences. Restricted mean survival time (RMST) was analysed. During a median 8.5-year follow-up, 603 deaths occurred. Long-term postoperative survival was lower with Class I trigger than in Class IIa trigger and no trigger (71.4 ± 1.9, 84.3 ± 2.3, and 88.9 ± 1.9% at 10 years, P < 0.001). Having at least one Class I criterion led to excess mortality (P < 0.001), while several Class I criteria conferred additional death risk [hazard ratio (HR): 1.53, 95% confidence interval (CI): 1.42-1.66]. Isolated Class IIa triggers conferred an excess mortality risk vs. those without (HR: 1.46, 95% CI: 1.00-2.13, P = 0.05). Among these patients, isolated PH led to decreased postoperative survival vs. those without (83.7 ± 2.8% vs. 89.3 ± 1.6%, P = 0.011), with the same pattern observed for AF (81.8 ± 5.0% vs. 88.3 ± 1.5%, P = 0.023). According to RMST analysis, compare to those operated on without triggers, operating on Class I trigger patients led to 9.4-month survival loss (P < 0.001) and operating on isolated Class IIa trigger patients displayed 4.9-month survival loss (P = 0.001) after 10 years.

Conclusion: Waiting for the onset of Class I or isolated Class IIa triggers before operating on DMR patients is associated with postoperative survival loss. These data encourage an early surgical strategy.