Left Atrial Index Predicts Mitral Regurgitation Outcome
Larger left atrial volume at diagnosis strongly associated with increased five-year mortality
THURSDAY, Aug. 5 (HealthDay News) -- Left atrial volume indexed to body surface area (LA index) predicts mortality risk in patients with organic mitral regurgitation (MR), according to research published in the Aug. 10 issue of the Journal of the American College of Cardiology.
Thierry Le Tourneau, M.D., of the Mayo Clinic in Rochester, Minn., and colleagues conducted a prospective study of 492 patients with organic MR, studying them at baseline with triple echocardiographic quantitation to determine MR severity, left atrial volume, and left ventricular characteristics. The LA index was calculated for each patient, and outcomes with medical and surgical management were analyzed.
The researchers found that the mean LA index for the group was 55 ml/m², with overall five-year survival of 80 percent; 28 percent had a cardiac event during this time period. After adjustment, the LA index was independently and significantly associated with survival (hazard ratio, 1.3 per 10 ml/m² increment). Patients with an LA index of 60 ml/m² or greater had significantly increased mortality and significantly increased numbers of cardiac events compared to those with an LA index of less than 40 ml/m². After mitral valve surgery, both mortality risk and cardiac event risk significantly decreased, and those in the highest LA index category no longer had an increased mortality or cardiac event risk (P > 0.30 for both).
"At a simple level, one might speculate that the addition to mitral valve surgery of procedures designed to target LA size could improve the prognosis, a testable hypothesis at least worth considering," write the authors of an accompanying editorial. "The addition of LA size to predictive instruments designed to guide the timing of mitral valve surgery may prove very useful in optimizing the value of this important procedure."