Monday, 25 November 2013

Repair or Replacement - a Randomised trial at last!


Mitral-Valve Repair versus Replacement for Severe Ischemic Mitral Regurgitation — NEJM

The commonest cause of mitral regurgitation in the 'West' is degenerative mitral disease (or mitral valve prolapse). Despite the lack of evidence from randomised studies, it is now accepted consensus that the majority of these patients should undergo mitral repair by an experienced mitral valve surgeon.

 Ischaemic mitral valve disease is the second commonest cause of a leaking mitral valve . The dilemma in the management of this condition has been whether moderate (mitral valve regurgitation is classed as trivial, mild, moderate and severe) mitral regurgitation should be dealt with in patients undergoing coronary bypass for ischaemic heart disease. The results of a recently published study favoured intervention in these patients. When it is treated, the valve is invariably repaired. Unfortunately, repairs of ischemic mitrals do not tend to be as durable as repairs of degenerative or prolapsing mitral valves. This was the driving force for the important trial whose long awaited results (above) were published in the New England Journal of Medicine.
The results are fascinating and perplexing. Although at 12 months, there are very little outcome differences between repair and replacement (headline used by the authors), the 12 month cumulative deaths curve seem to tell a different story. Although there were more postoperative 30 day deaths in the replacement group,  deaths in the repair group gradually caught up over the ensuing 11 months.
The same applies to rehospitalisations with fewer early readmissions in the repair group and reversing of the situation over the rest of the year. I am not sure how to interpret the results. The most obvious explanation is that  repair failures over the course of 12 months are responsible for the disappointing results in the non-replacement group.
I hope this is not the end of the story. There are surgical (and more recently technological) techniques to improve the durability of repair. These could make the initial superiority of repair over replacement of ischaemic mitral valves stick for the duration. Furthe