Estimation of Mean Left Atrial Pressure in Patients with Acute Coronary Syndromes: A Doppler Echocardiographic and Cardiac Catheterization Study

Abstract

Doppler echocardiography, including the ratio of transmitral E to tissue Doppler e' velocities (E/e'), is widely used to estimate mean left atrial pressure (mLAP). This method, however, has not been validated in patients with acute coronary syndromes. Fifty-seven patients with acute coronary syndromes who underwent left heart catheterization and transthoracic echocardiography within 8hours of each other were retrospectively analyzed. Forty-two of the patients (74%) were men, with a mean age of 65±11years. Patients with known cardiomyopathy, atrial fibrillation, or left-sided valvular disease were excluded. Doppler mLAP was estimated using Nagueh's formula (1.24×[E/e']+1.9). Invasive mLAP was estimated using the formula of Yamamoto etal. (1.20×mean left ventricular diastolic pressure - 0.82), wherein we averaged left ventricular diastolic pressure starting from the isovolumic relaxation phase to the post-A inflection point. Subanalyses were performed in groups with reduced or normal left ventricular ejection fraction (EF). There was stronger agreement between the two techniques to estimate mLAP in the reduced EF group (r=0.73, r2=0.53, P<.001) compared with the normal EF group (r=0.33, r2=0.11, P=.08). The κ statistic for agreement was 0.34 for the overall study cohort, suggesting fair agreement according to partition values of mean mLAP: <8, 8 to 15, and >15mm Hg. Left atrial volume index did not correlate with invasively estimated mLAP in this cohort. In patients with acute coronary syndromes, Doppler- and catheter-derived estimates of mLAP correlate well in patients with reduced EFs. In the acute setting, echocardiographic evaluation is a reliable adjunct to clinical examination in assessment of heart failure in this subgroup of patients.