CHICAGO – Early repair and greater reliance on experienced surgical centers are key to the new guidelines on the management of mitral valve disease.
It’s been 8 years since the last American Heart Association/American College of Cardiology guideline on valvular heart disease in 2006, with little change in the 2008 update.
The 2014 guidelines, however, have substantiative changes, including the decision to begin talking about valvular disease and at-risk patients much as we do for heart failure, guideline committee member Robert Bonow said at the Heart Valve Summit 2014.
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Dr. Robert Bonow
The 2014 guidelines, published earlier this year, include four stages of valvular heart disease:
Stage A, for people at risk of valvular disease such as those with bicuspid valves, a history of rheumatic heart disease, or mitral valve prolapse without regurgitation.
Stage B, for mild to moderate, asymptomatic disease.
Stage C, for severe, asymptomatic disease, including those with normal left ventricular function (stage C1) or depressed LV function (stage C2).
Stage D, for severe, symptomatic valve disease.
The new guidelines also drive home the point that primary and secondary mitral regurgitation (MR), while they can be difficult to distinguish, are separate diseases with different pathophysiologies, natural histories, management strategies, and outcomes, said Dr. Bonow, director of the Center for Cardiovascular Innovation, Northwestern University, Chicago.
Class 1 surgical indications for primary MR, or diseases of the valve, are symptomatic patients and asymptomatic patients with LV systolic dysfunction. This continues to be defined as an ejection fraction of < 60% or an end-systolic dimension > 40 mm, although new data have suggested that even smaller systolic dimensions may have prognostic importance, he noted.
Pulmonary hypertension and atrial fibrillation are class IIa indications for surgery in asymptomatic, primary MR.
Critics would argue that patients shouldn’t be allowed to develop these indications because they may be irreversible, but the reality is that many patients arrive in your office with one or more indications already in place, Dr. Bonow said. The real issue is whether mitral valve repair is feasible and can improve survival in patients who have normal LV function and none of these indications, with the guidelines clearly tipping in favor of early surgery for asymptomatic MR patients.
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Dr. David H. Adams
Dr. Bonow highlighted recent long-term outcomes data from Dr. Tirone David’s group (Circulation 2013;127:1485-92) showing that overall survival among patients undergoing mitral valve repair for degenerative diseases is 75% at 20 years for those with functional class (FC) I disease, 66% with FC II, 52% with FC III, and only 32% for those with FC IV.
“I think these data, along with many other series, are quite important in identifying the risks we have for our patients for waiting too long, and if we can refer our patients to an expert surgical team for these valves to be repaired, their outcomes will be much better,” Dr. Bonow said.
The guidelines include the class I indication that repair is better than mitral valve replacement for primary MR and that patients should be referred to “centers experienced in repair.” Instead of stating that there should be a 90% or greater likelihood of a durable repair without residual MR for a patient undergoing elective surgery at that center, the 2014 threshold is now set at more than 95%.
“We really want to make sure patients are going to an experienced center,” he said.
Despite the emphasis on a heart team approach and referral to experienced centers, the term “experienced” has not been fully defined, Dr. Bonow acknowledged.
“Our medical and surgical societies need to be working together to start defining what we mean by ‘experienced,’ what we mean by ‘centers of excellence,’ and that process is already underway,” he added.
Dr. David H. Adams, chair of cardiovascular surgery at Mount Sinai Hospital, New York City, said that there’s no question asymptomatic patients need to be treated in experienced repair centers, but questioned whether the 95% threshold is realistic. Although repair rates are increasing worldwide, Society of Thoracic Surgery published data show a wide disparity in mitral repair that would be troublesome in an asymptomatic population. Mandatory reporting data from New York State, home to several experienced heart programs, also show that 45% of the latest 4,325 mitral valves with interventions were replaced, rather than repaired. Dr. Adams added that data are similar across the world.
He also urged caution about an “asymptomatic surgery for all” attitude, emphasizing judgment is necessary, particularly in elderly patients or in those who are very early in the course of severe regurgitation with no evidence of ventricular dilation or declining systolic function.