Early Surgery Bests "Watchful Waiting" in Severe MR Patients Without Symptoms

August 13, 2013

ROCHESTER, MN — Patients with severe mitral regurgitation (MR) without a class I indication for surgical intervention fared significantly better when treated with surgery than patients who underwent "watchful waiting" while treated with medical therapy, according to the results of a new analysis, published in the August 14, 2013 issue of the Journal of the American Medical Association[1].

Overall, there was no significant difference in short-term mortality or the risk of new-onset heart failure, but the early surgical correction of MR was associated with a significantly lower risk of death at 10 years compared with patients who were monitored and managed medically.

"A decade ago, if a patient had a severe leak in a valve, you'd say, fine, I can send this patient to surgery, but if they came out with a bad repair or replacement, you'd wonder if you were really helping the patient," lead investigator Dr Rakesh Suri (Mayo Clinic, Rochester, MN) told heartwire . "But the game has changed now. We're offering a very effective, very durable operation that is beneficial to patients. This study shows us that not only are the immediate benefits apparent, but the long-term benefits are profound. Patients are living longer and enjoying a high quality of life because of freedom from heart-failure symptoms."

The American College of Cardiology/American Heart Association (ACC/AHA) guidelines for the treatment of MR state that surgery is a class I indication for symptomatic patients or those with an ejection fraction <60% or left end-systolic diameter >40 mm. Surgery is a class IIa recommendation in asymptomatic patients or those without changes in the left ventricle only if the chance of surgical success is at least 90%. The European guidelines, in contrast, recommend against surgery in asymptomatic MR patients and those without left ventricular changes.

In an editorial accompanying the study[2], Dr Catherine Otto (University of Washington School of Medicine, Seattle) points out that there are no data from randomized controlled trials on the optimal timing of surgery for patients with asymptomatic MR. While the benefit observed in the present study might be overestimated because of unmeasured biases in selecting patients for surgery, "the findings indicate that it may be more beneficial to offer early surgery for patients with severe MR due to a flail mitral-valve leaflet rather than waiting for symptom onset or classic indications for intervention."

No Early Risk, but Long-Term Benefit

Using data from the Mitral Regurgitation International Database (MIDA) registry, Suri and colleagues sought to compare effectiveness of early MR surgery following the diagnosis of MR due to flail leaflets. In total, six tertiary-care centers from Europe and the US treating 1021 patients were included in the analysis. None of the patients had a class I indication for surgery. Of these, 575 patients were managed with medical therapy and 446 underwent MR surgery within three months of MR diagnosis.

Within the first three months, 1.1% of patients treated with surgery died compared with 0.5% of those managed medically, a nonsignificant difference. Rates of new-onset heart failure were similar between the two treatments, but new-onset atrial fibrillation was significantly greater among those treated with surgery (6.2% vs 1.2%, respectively; p<0.001).

During a median follow-up of 10.3 years, 319 patients died. Survival at five, 10, and 20 years following MR surgery was 95%, 86%, and 63% compared with survival rates of 84% at five years, 69% at 10 years, and 41% at 20 years among those who were managed medically. The survival difference between the two treatments was statistically significant, and the results were confirmed in propensity score-matched and inverse-probability–weighted analyses. In addition, the incidence of new-onset heart failure was also significantly lower with surgery, while the early risk of atrial fibrillation did not translate into a long-term hazard.

Patient Outcomes, Surgery vs Medical Management (Hazard Ratio [95% CI]), With Cohort Cox Regression Models

Outcome Overall cohort, n=1021 Propensity score-matched cohort, n=648 Inverse probability-weighted cohort, n=1017
Mortality 0.55 (0.41–0.72) 0.52 (0.35–0.79) 0.66 (0.52–0.83)
Heart failure 0.29 (0.19–0.43) 0.44 (0.26–0.76) 0.51 (0.36–0.72)
Atrial fibrillation 0.85 (0.64–1.13) 1.28 (0.84–1.95) 1.05 (0.81–1.37)

To heartwire , Suri explained that the patients in the study had severe MR caused by flail leaflets, either due to a ruptured chord or a chord that is flipping into the left atrium, so the results can be extended to all patients with severe MR caused by degenerative disease. Surgical mitral-valve repair is typically an option for 95% to 99% of patients with severe MR, he said, including a range of patients with simple to complex disease.

The Risks, Benefits, and Alternatives

At the Mayo Clinic, Suri said that physicians and surgeons typically have a "data-driven discussion" with the patient when they are identified as having severe MR. The risks, benefits, and alternatives are discussed, but this latest analysis would be helpful in future talks with patients. Furthermore, the era of the innocuous heart murmur is past, said Suri. Given the availability of echocardiograms, physicians owe it to their patients to diagnose the problem and the degree of leakage or blockage that exists. Once that is known, patients can be stratified by risk so that those with severe MR can be given clear recommendations for treatment.

"It'll be very useful to sit down with the patient and show them the implications of deferring surgery vs the benefits of having mitral-valve repair surgery early," he said. "When you sit down and have a discussion with patients detailing the long-term implications of both approaches, either watchful waiting or early surgery, most often in our practice patients will elect to proceed with early surgery."

In the editorial, Otto notes that the patients included in the study were atypical, since most patients with chronic severe MR in clinical practice are referred for surgery at symptom onset or when there are signs of severe left ventricular dysfunction. The decision of surgery vs wait-and-watch for MR patients with a flail leaflet can be challenging for physicians, given the lack of robust clinical trial data, she added. Moreover, these patients also tend to be older and have coexisting cardiac conditions and comorbidities.

"For these reasons, referral of patients with significant valve dysfunction to a heart-valve center is recommended so that options for the restoration of normal valve function, procedural risks, long-term outcomes, and patient preferences can be discussed in a team approach that includes valve experts, imaging specialists, interventional cardiologists, and cardiac surgeons," according to the editorialist.

To heartwire , Suri agreed, noting that the surgery is a particularly tricky one and patients should be referred to high-volume tertiary-care centers for the best outcomes.

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