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

Abstract

Background: 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.

Methods: Fifty-seven patients with acute coronary syndromes who underwent left heart catheterization and transthoracic echocardiography within 8 hours of each other were retrospectively analyzed. Forty-two of the patients (74%) were men, with a mean age of 65 ± 11 years. 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 et al. (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).

Results: 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 >15 mm Hg. Left atrial volume index did not correlate with invasively estimated mLAP in this cohort.

Conclusions: 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.

Keywords: Acute coronary syndrome; Doppler echocardiography; Left ventricular end-diastolic pressure, LVEDP; Left ventricular filling pressure; Mean left atrial pressure, mLAP.