Mitral repair added to CABG lowers mortality
MedWire News: Mitral valve repair at the time of coronary artery bypass graft (CABG) surgery may decrease perioperative mortality and result in improved survival in patients with severe left ventricular (LV) dysfunction and moderate-to-severe mitral regurgitation (MR), according to investigators in the STICH (Survival in the surgical Treatment of IschemiC Heart failure) trial.
European guidelines state that mitral valve surgery is indicated for patients with a primary indication for CABG and severe ischemic MR with an ejection fraction greater than 30% (ESC/EACTS guidelines, Class I, Level C). The guidelines also say that "mitral valve surgery should be considered in patients with a primary indication for CABG and moderate ischemic mitral regurgitation, provided valve repair is feasible and performed by experienced operators."
In the STICH trial, which studied CABG surgery in patients with LV dysfunction, 1212 patients with an ejection fraction of 35% or less and coronary artery disease amenable to CABG were randomly assigned to medical therapy alone (602 patients) or medical therapy plus CABG (610 patients). The decision whether to also perform mitral valve repair was left to the operating surgeon, however.
The current study looked at the question of whether the baseline severity of MR in STICH trial participants has prognostic value, and whether mitral repair at the time of CABG surgery has an effect on survival in patients with moderate-to-severe disease compared with those treated with medical therapy only.
In all, 401 patients with either no or only trace amounts of MR, 493 with mild MR, and 195 with moderate-to-severe MR were available for a per-protocol analysis. The primary endpoint was all-cause mortality. Major secondary endpoints were cardiovascular mortality, and all-cause mortality plus cardiovascular hospitalization. The longest follow-up period was 6 years.
Among patients treated with medical therapy only, the HR for mild versus no MR was 1.60, while for moderate or severe MR versus none it was 1.97.
Among patients with mild MR, CABG surgery was associated with a significant 36% decrease in mortality compared with medical therapy.
In those with moderate-to-severe MR, 52% of patients who received medical therapy only died, compared with 43% who underwent CABG, but this difference was not statistically significant. After adjustment for baseline prognostic variables, the HR for CABG with mitral surgery versus CABG alone in this group was 0.45 (p=0.025).
In patients with moderate-to-severe MR, the post-operative course "was definitely more complicated, with more ventilation time, longer ICU [intensive care unit] time, and longer hospitalization, as well as longer inotropic support and more intra-aortic balloon pump use," said co-investigator Marek Deja (Medical University of Silesia, Katowice, Poland).
However, Deja added: "The mortality was significantly less in patients [who had] a mitral valve procedure."
"The STICH trial is a good trial, it's a large trial, and we have to compliment the authors who provide us with such a large set of contemporary data, with well-characterized patients with LV dysfunction, and for providing us also with 5-year follow-up," said Alec Vahanian (Bichat Hospital, Paris, France), the invited discussant.
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By Neil Osterweil