September 6th, 2013
Early Surgery vs. Watchful Waiting for Flail-Leaflet Mitral Regurgitation
CardioExchange’s John Ryan interviews Rakesh M. Suri and Maurice Enriquez-Sarano about their research group’s study, published in JAMA, of patients in the Mitral Regurgitation International Database.
At 6 tertiary care centers in Europe and the U.S., researchers compared the effectiveness of initial medical management (nonsurgical observation) with early mitral valve surgery after diagnosis of mitral regurgitation (MR) due to flail mitral-valve leaflets. Of 1021 consecutive patients without ACCF/AHA class I triggers (heart-failure symptoms or LV dysfunction), 575 were initially medically managed and 446 underwent mitral valve surgery within 3 months after detection of severe MR. At 3 months, the two groups were similar in their rates of mortality and new-onset heart failure; however, at 10 years, the mortality rate was significantly lower among patients who underwent early surgery (14% vs. 31%), as was the long-term risk for heart failure (7% vs. 23%). No advantage in late-onset atrial fibrillation was observed. The findings were confirmed in risk-adjusted models.
Ryan: Did the decisions about who would have surgery differ between the earlier part of the study, when repair was less frequent, and the later part?
Suri and Enriquez-Sarano: Mitral-valve repair was performed across the MIDA network at a high frequency in both the early surgery and initial medical management groups throughout the study. Given the interim emergence of evidence detailing high repair rates for all categories of leaflet prolapse, improved safety, and excellent durability of repair, referring physicians’ attitudes about early surgical referral may have evolved concurrently.
Ryan: Why do you think some patients underwent surgery and others did not — and did that vary much by center?
Suri and Enriquez-Sarano: Patients who underwent early surgery had larger left-atrial and left-ventricular dimensions, so the existence of adverse remodeling consequences associated with severe MR may have influenced physicians to recommend early surgery. However, despite a greater apparent preoperative effect of MR, as assessed by chamber dimensions in the early surgical group, these patients had better late clinical outcomes, including superior long-term survival and freedom from heart-failure symptoms. Notably, patients with severe, degenerative MR were referred for early surgery at advanced repair centers before heart-failure symptoms or LV dysfunction (class I triggers mandated by practice guidelines) occurred — a strategy that was clearly beneficial.
Ryan: How should this study be integrated into the new guidelines?
Suri and Enriquez-Sarano: This is the largest study of early surgery in asymptomatic patients with severe, degenerative MR in the absence of guideline-based class I triggers for intervention. As such, the study provides sobering evidence that prompt surgical correction of severe MR has important long-term benefits.
We therefore would anticipate that this evidence might lead to the modification of guideline-based recommendations, with the proviso that such patients be referred to advanced repair centers where the likelihood of performing mitral repair safely and effectively is very high (repair rate >90–95%; risk <0.5%; high-quality echocardiography and reoperation rate <1–1.5%/year).
It is also important that (a) echocardiography be used to carefully define MR etiology/severity and (b) the influence of patient comorbidities be considered, to ensure that mitral-valve repair alone will improve life expectancy. We propose the creation of a National Mitral Regurgitation Registry, to ensure that practices and outcomes are continuously tracked, monitored, and reported.
Finally, data-driven discussions regarding the referral of patients for less-invasive surgical options (robotic, thoracoscopic, mini-thoracotomy) should also occur at high-volume referent valve centers. This will ensure that proven techniques are used to perform the technical aspects of the mitral-valve repair itself and that outcomes are followed and reported.
These a priori criteria, necessary for the surgical referral of asymptomatic degenerative severe MR patients, are likely (at least initially) to be most readily applicable in high-volume reference mitral-valve repair centers that have an experienced multidisciplinary heart-valve team.
JOIN THE DISCUSSION
How do the findings from this new analysis affect your view of the value of early surgery in this clinical setting?