Impact of Early Surgery on Survival of Patients With Severe Mitral Regurgitation
Is there an association between the timing of surgery and long-term survival in patients with severe degenerative mitral regurgitation (MR)?
A cohort of 481 patients with severe degenerative MR between 1995 and 2007, and at least one American College of Cardiology/American Heart Association (ACC/AHA) guideline indication for surgery, was identified from the Duke Cardiovascular Disease Databank. Exclusion criteria were rheumatic disease, congenital mitral valve disease, hypertrophic cardiomyopathy, coronary disease in >1 vessel, endocarditis, other severe valve disease, or past valve repair/replacement. Patients were grouped into early surgery (≤2 months of presenting with surgical indications) and late surgery (>2 months). An adjusted Cox regression model was constructed for time to death after 2 months, with a time-dependent covariate term for late surgery.
A total of 168 patients had early surgery (median time to surgery, 0.42 months), of whom 153 were followed up after 2 months; 94 patients had late surgery (median time to surgery, 8.75 months); and 219 were medically managed. A total of 127 (76%) of 168 patients in the early surgery group and 84 (89%) of 94 in the late surgery group underwent mitral repair (p = 0.02). Over 5.6-year median follow-up, there were 35 deaths (21%) in the early surgery group, with two occurring before 2 months, and 20 deaths (21%) in the late group. In the multivariable model, patients undergoing early surgery had a lower hazard for death than those who underwent late surgery (hazard ratio [HR], 0.54; 95% confidence interval [CI], 0.30-0.97; p = 0.04). Mitral repair was independently associated with survival (HR, 0.45; 95% CI, 0.25-0.83; p = 0.01).
In patients with severe degenerative MR who presented with guideline indications for surgery, those who underwent earlier surgery had better survival than did patients who underwent surgery >2 months after identification. These data support the current guidelines for early referral to surgery in patients with severe MR for enlarged left ventricular dimensions, reduced ejection fraction, and symptoms, rather than delaying surgery. Larger randomized trials are needed to definitively answer the question of optimal timing of surgery in patients with severe degenerative MR.
Data from this retrospective, observational study support that, once there is an indication for surgical intervention for severe degenerative MR, outcomes might be better if surgery is not deferred. Inasmuch as chronic MR is an indolent disease, the development an ACC/AHA indication for intervention heralds decompensation, and complacency should be discouraged. As always with an observational study, patients who underwent earlier surgery might have differed in some (unmeasured) aspects compared to those who underwent later surgery. Arguably, many people take the term ‘early surgery’ for MR to mean intervention before there is an ACC/AHA indication for surgery; this study did not address whether outcomes are superior with such ‘prophylactic’ mitral repair.
Keywords: Hypertrophy, Left Ventricular, Endocarditis, Follow-Up Studies, Mitral Valve Insufficiency, Cardiology, Cardiomyopathy, Hypertrophic, Heart Valve Diseases, Coronary Disease, Mitral Valve, United States
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