Marlene Busko

May 05, 2014

TORONTO, ON — Surgeons who perform at least 20 mitral-valve operations a year are more likely to treat patients who have moderate to severe mitral regurgitation by repairing rather than replacing the valve, new research suggests[1]. This threshold case load was determined in a study of mitral-valve surgeries performed in the state of Virginia in the past 10 years.

Valve repairs rather than replacement operations were also more likely to occur in high-volume hospitals, according to this study, which was presented here at the American Association for Thoracic Surgery (AATS) 2014 Annual Meeting .

Surgeons who carried out more than 20 mitral-valve operations a year performed valve repairs in 73% of cases, while surgeons doing fewer than 20 such operations a year only performed valve repairs in 26% of cases.

"The primary clinical implications of this work relate to the demonstration that surgeon mitral-valve volume and experience are important predictors of the likelihood of performing mitral repair and that this may impact referral patterns in the future," Dr Damien J LaPar (University of Virginia, Charlottesville) told heartwire in an email.

"As reflected in prior studies and in current [American College of Cardiology/American Heart Association] ACC/AHA guidelines, surgeon experience is important in the success of mitral repair," he noted.

Mitral-Valve Repair May Be Underutilized

The ACC/AHA guidelines recommend surgery over medical management for patients with severe mitral-valve regurgitation, according to a statement from the AATS. But only about half of patients with severe mitral-valve malfunction have surgery. In addition, mitral-valve repair, which is associated with better perioperative outcomes and survival compared with valve replacement, appears to be underutilized, the statement adds.

Specifically, "guidelines recommend mitral-valve repair for all nonischemic, nonrheumatic, mitral regurgitation where heavy calcification of the annulus does not exist . . . especially . . . for posterior leaflet prolapse due to degenerative mitral-valve disease or ruptured chordae tendineae," LaPar explained.

The researchers sought to determine whether surgeon volume (a surrogate for experience) and hospital volume influenced whether patients' leaking mitral valves were repaired or replaced in the state of Virginia from 2001 to 2011.

They analyzed Society of Thoracic Surgery (STS) records from 100 cardiac surgeons in 17 centers, representing 99% of mitral-valve surgeries performed in the state.

During this time, 2516 patients (60%) had mitral-valve repair and 1662 patients had mitral-valve replacement.

The hospitals performed a median of 54 mitral-valve operations a year, but this varied widely, from five to 128 operations a year. Similarly, surgeons performed a median of 13 mitral-valve operations a year, which ranged from none to 58 operations a year.

Among the hospitals, the proportion of mitral-valve surgeries that were mitral-valve repairs varied from 35% to 70%. Some surgeons performed no mitral-valve repairs, whereas mitral-valve repairs represented up to 90% of the mitral-valve caseload for other surgeons.

In hospitals where more than 20 mitral-valve operations were done each year, valves were repaired (rather than replaced) in 62% of cases, while in hospitals where fewer than 20 mitral-valve operations were done each year, valves were repaired in 37% of cases.

"We were not too surprised by our findings, and we expect that our results are generalizable to most other centers across the United States," LaPar said.

But Were These All "Repairable" Valves?

"The study serves to reinforce the awareness among surgeons that mitral valves should probably be repaired when possible," study discussant Dr David A Fullerton (University of Colorado, Denver), STS president, told heartwire in an email.

"However, this study was not designed to address the question as to whether repair is always better than replacement. A body of data continues to grow documenting that in certain circumstances, replacement is equivalent to repair."

He noted, "Specifically, some regurgitant mitral valves should be readily repaired by all surgeons, and other types of pathology are far more complex. The difficulty is therefore in attempting to identify what percentages of 'repairable' valves actually are repaired within a given center."

LaPar and Fullerton have no disclosures to report.

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