By Michael H. Crawford, MD, Editor
Synopsis: A large, single-center, contemporary long-term follow-up of degenerative mitral valve disease patients undergoing mitral valve repair surgery has shown that 30-day post-operative mortality is < 1% and a median almost nine-year follow-up survival is 90%. Somewhat worse outcomes were observed in those with preoperative symptoms, reduced left ventricular function, atrial fibrillation, and isolated anterior leaflet disease.
Source: Del Forno B, Ascione G, Carino D, et al. Long-term outcomes of contemporary surgical repair for degenerative mitral regurgitation. J Am Coll Cardiol. 2025;85(8):835-847.
Surgical repair of degenerative mitral valve regurgitation (MVr) has improved markedly recently, and patients have been referred for surgery earlier than they were previously. However, there is a paucity of data on long-term outcomes, which is important with the emergence of transcutaneous edge-to-edge repair (TEER). Thus, the results of MVr at a high-volume center of excellence in Italy is of interest.
Patients (n = 3,317, 69% men, median age 57 years) undergoing MVr by five surgeons at the San Raffaele University Hospital in Milan from 2008-2017 for degenerative MV disease were followed for a median of 8.9 years (maximum 14). The primary outcome was long-term survival. Secondary outcomes included hospital mortality, freedom from reoperation or rehospitalization for heart failure (HF), and complications such as infective endocarditis and stroke. All outcomes were independently adjudicated by the Italian National Agency for Regional Health Care Services using the National Health System database. Most of the patients were in New York Heart Association class I (34%) or II (55%) and 11% were class III or IV. Median left ventricular ejection fraction (LVEF) was 60% and the mean EuroSCORE II was 0.92%, indicating low operative risk. Most of the patients (92%) had severe mitral regurgitation (MR) and the rest had either symptoms, atrial fibrillation (AF), or reduced LVEF as indications for surgery. A majority had isolated posterior leaflet involvement (71%). Almost all of the subjects had a concomitant annuloplasty (98%) and 15% also had a tricuspid valve repair.
Prior to discharge, 97% had mild or less MR, with the rest having mild to moderate MR. The mean MV gradient was 3 mmHg. The 30-day hospital mortality was < 1%. The 10-year survival was 90%, with preoperative symptoms, AF, reduced LVEF, and anterior leaflet involvement associated with an increased risk. Freedom from reoperation was 97% at 10 years, with anterior leaflet disease, a second cardiopulmonary bypass run, and more than mild MR at discharge being associated with an increased risk. Freedom from rehospitalization for HF was 92% at 10 years, with age, prior HF hospitalization, preoperative symptoms, and anterior leaflet disease associated with an increased risk. Valve complications were infrequent over 10 years (infective endocarditis 1% and ischemic stroke 3.6%). The authors concluded that MVr in a high-volume center is associated with low in-hospital and long-term mortality. Preoperative symptoms, reduced LVEF, AF, and isolated anterior leaflet involvement are associated with worse outcomes.
Commentary
For those unfamiliar with the San Raffaele University Hospital, it is a renowned cardiac surgery center that brought us the “Alfieri stitch” (an early surgical repair technic for MR), the success of which led to the development of TEER. The results of this study speak to the high degree of surgical skill at this institution. Thus, their contemporary long-term results represent the best outcomes that can be expected from current MVr surgical techniques, and they are quite good. This study then becomes an excellent benchmark for evaluating future longer-term studies of the outcomes of TEER.
The major strength of the Italian study is that all the endpoints were adjudicated by an independent national organization, which was linked to Italy’s national health system, so not only were the results reliable but they also were free of missing values. The downside of this approach is that the data are limited to hard endpoints such as death, reoperation, and HF admissions that are captured in a nationwide database, whereas softer endpoints, such as recurrent MR and other echocardiographic measures, were not available in the national database. Also, post-operative visit information, such as functional state, arrhythmias, and oral anticoagulation use, were not available. In addition, this was a low-risk cohort (the mean EuroSCORE II was 0.92%). The primary indication for MVr was the presence of severe MR. Few patients had more than mild symptoms (11%), AF (16%), or reduced LVEF (mean 60%).
Currently there are randomized trials evaluating MVr vs. TEER. However, such studies will be difficult to interpret because of the limitations of TEER. Percutaneously clipping the MV cannot adequately address anterior leaflet disease or Barlow’s disease. Also, TEER currently does not involve annuloplasty, which is believed to be an integral part of MVr, with poorer outcomes when it is omitted. In addition, TEER currently cannot deliver artificial chords and other fine points of MVr. I believe these outstanding results from a single center of excellence in cardiac surgery will relegate TEER to a secondary less invasive alternative when surgery is too high-risk or is not expected to be successful.
Finally, it should be emphasized that almost all the patients did not have limiting symptoms, low LVEFs, elevated pulmonary artery pressures, or atrial fibrillation. They were referred to surgery mainly for the presence of severe MR (92%) before these complications occurred. Thus, this study supports the concept that earlier surgery when severe MR is recognized is preferable to waiting for symptoms or complications to occur.
Michael H. Crawford, MD, is Professor Emeritus of Medicine and Consulting Cardiologist, UCSF Health, San Francisco.
A large, single-center, contemporary long-term follow-up of degenerative mitral valve disease patients undergoing mitral valve repair surgery has shown that 30-day post-operative mortality is < 1% and a median almost nine-year follow-up survival is 90%. Somewhat worse outcomes were observed in those with preoperative symptoms, reduced left ventricular function, atrial fibrillation, and isolated anterior leaflet disease.
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