Mitral Valve Repair During Bypass Surgery Could Improve Heart Function

Researchers at Imperial College (London, United Kingdom) randomized 60 patients with moderate functional ischemic mitral regurgitation (FIMR) to receive CABG only or dual procedures CABG and MVR annuloplasty; all patients had moderate mitral valve leaks caused by their ischemic heart disease. The researchers examined the patients' exercise capacity, heart function, and heart size, both before and one year after surgery.

The researchers found that in the year after surgery, the patients who had MVR and CABG improved 3 mL/kg/min in exercise capacity, compared to 1 mL/kg/min in patients who only had CABG. Heart size was reduced by 24% in the dual-procedure patients, versus 10% in the CABG-only group. Blood levels of plasma brain natriuretic peptide (pBNP, which is increased when the heart muscle is over-stretched or in heart failure) was lower in those who had the dual procedure (54.8 pmol/L) compared to those with CABG only (108.9 pmol/L). The study was presented as an American Heart Association (AHA) Emerging Science Series webinar, held during February 2012 in Dallas (TX, USA).

“The majority of these patients come to surgery not because of the mitral regurgitation but for revascularization of their ischemic coronary disease, and by convention, if the mitral regurgitation has not been severe, a lot of surgeons attempt just to revascularize,” said lead author and webinar presenter Kok Meng John Chan, MD. “But we have increasing evidence that [mitral regurgitation] is not a benign condition and that even moderate degrees of ischemic mitral regurgitation are significant.”

Current AHA guidelines give MVR in patients with ischemic mitral regurgitation undergoing CABG a class IIa (level of evidence B) recommendation. The researchers believe that the study and several more ongoing studies will eventually push that to a class I recommendation.

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