Left atrial function and mortality in patients with NSTEMI an MDCT study.

OBJECTIVES

We sought to test the hypothesis that measures of left atrial (LA) function are independent predictors of mortality in patients with acute myocardial infarction.

BACKGROUND

Left atrial maximal volume (LAmax) is known to predict mortality in patients with acute myocardial infarction. In a previous pilot study, however, we found that LA function in terms of fractional change and left atrial ejection fraction (LAEF) assessed by multidetector computed tomography (MDCT) is more closely related to clinical heart failure than LAmax.

METHODS

We prospectively included 384 patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI) who underwent retrospectively gated, 64-slice MDCT coronary angiography and subsequent measurements of LA size and function. All patients were treated according to the current guidelines based on invasive coronary angiography. Patients were followed for a minimum of 2 years. The study endpoint was all-cause mortality.

RESULTS

The median follow-up time was 36 months (range 10 to 1,551 days). During follow-up, 35 (9%) patients died. Overall, 1- and 2-year survival in the study cohort was 97% and 94%. LA size and mechanical function was obtained in all patients: mean LAmax was 55 ± 11 ml/m(2), LA minimal volume 31 ± 11 ml/m(2), fractional change 45 ± 9%, and LAEF 32 ± 9%. Using a Cox proportional hazards model with adjustments for age, number of diseased coronary vessels, left ventricular ejection fraction (LVEF), and Killip class, both fractional change (hazard ratio [HR]: 0.65; 95% confidence interval [CI]: 0.45 to 0.94) and LAEF (HR: 0.63; 95% CI: 0.44 to 0.91) remained independent predictors of mortality. In contrast to this, LAmax was not significantly associated with an increased risk of mortality in this population.

CONCLUSIONS

In a low-risk group of patients with NSTEMI, reduced LA function is an independent predictor of mortality and provides prognostic value incremental to that of LAmax.