No more wait & see: Mitral registry data give edge to early surgery

For cardiac surgeons, the wait may be over. Patients with flail mitral valve regurgitation who underwent early surgery had better long-term survival and lower risk of heart failure than counterparts who were medically managed, according to a study published Aug. 14 in JAMA. But watchful waiting still may be the best approach in some circumstances.

North American and European guidelines are at odds over mitral valve surgery in patients with severe mitral valve regurgitation who have no class 1 surgical triggers, with the American College of Cardiology and the American Heart Association giving a class IIA recommendation and the European Society of Cardiology designating it at a less favorable class IIB. “In the absence of level I evidence from a randomized trial, it is necessary to study the consequences of current international mitral regurgitation management strategies using alternative means,” wrote Rakesh M. Suri, MD, DPhil, of the Mayo Clinic in Rochester, Minn., and colleagues.

Their solution was to design a study based on the Mitral Regurgitation International Database, a six-center registry that allowed them to compare an early surgery approach with medical management in patients diagnosed with degenerative mitral regurgitation with a flail leaflet. To be eligible for inclusion, patients had to have no or minimal symptoms and no left ventricular dysfunction.  

Suri et al defined early surgery as surgery within three months after diagnosis. Medical management (watchful waiting) was initially a management strategy without surgery in the first three month followed by either more medical management or surgery. The primary endpoint was all-cause mortality and secondary endpoints were heart failure and new onset atrial fibrillation. The registry spanned a 25-year period, from 1980 to 2004.   

They identified 1,021 patients for the analysis—575 in the medical management group and 446 in the early surgery group—for a median follow-up of 10.3 years. In the medical management group, 87 percent had valve repair surgery recommended at a median of 1.65 years after diagnosis.

The two groups had similar mortality rates and new onset heart failure rates at three months. But 10-year survival rates favored the early surgery approach, at 86 percent, compared to 69 percent for medical management. Long-term heart failure rates were lower with early surgery, at 7 percent vs. 23 percent for medical management at 10 years. Neither approach had a leg up in late-onset atrial fibrillation. Multivariable Cox models, propensity score matching and inverse probability-weighted analyses confirmed the findings.

“[E]arly surgical correction of mitral valve regurgitation was associated with a significant survival benefit (total mortality decrement of approximately 40%) and diminished heart failure risk (reduction of approximately 60%)," wrote the authors. “Furthermore, the lasting benefit of early surgery appeared to be sustained 20 years following diagnosis and observed in subgroups with or without class II triggers for surgery, and with or without (non–heart failure–related) minor subjective manifestations.”

Suri et al pointed out that despite the various analyses, they could not rule out the possibility of residual confounding. Still, their findings underscored that early surgery provided an opportunity to improve long-term survival and reduce the risk of heart failure in patients with flail mitral valve regurgitation “through early referral for surgical correction where appropriate expertise exists.”

Catherine M. Otto, MD, of the University of Washington School of Medicine in Seattle, wrote in an accompanying editorial that unmeasured clinical bias from patient selection may overestimate the differences between the two approaches. She pointed out that early surgery in patients with severe mitral regurgitation “is reasonable” when the odds of success are high and operative risk low. But in the reverse scenario—low benefit, high risk—it “remains uncertain.”

Otto described decisions about the timing of surgical treatments as a daily challenge. Other factors such as image quality, institutional and surgical team expertise and the patient’s age and comorbidities factor into decisions. She recommended that physicians refer these patients to a heart center with multidisciplinary team of experts.