E/E’ Ratio as a Noninvasive Measure of Left Ventricular Filling Pressure in Patients with Non-ST-elevation Acute Coronary Syndromes (NSTEACS)

Abstract

Background: The E/e’ ratio has an established role in the assessment of left ventricular filling pressures (LVFP) in stable patients. There is limited data on the assessment of LVFP with the E/E’ in patients with NSTEMI. We sought to perform an invasive haemodynamic validation study with near-simultaneous measurement of Doppler echocardiographic parameters and invasively measured LVFP in patients with NSTEMI. Methods: A total of 29 unselected patients with NSTEMI underwent a limited transthoracic echocardiogram on the cardiac catheterisation table immediately prior to coronary angiography. Mitral inflow E-wave and tissue Doppler derived E’ at the septal and lateral mitral annulus was measured. Invasive measurement of LVFP was then performed with a pigtail catheter in mid shallow expiration. Results: The mean age of patients was 64.1 years, with 72% males. The mean LVEF was 52%. Angiographic findings included 3-vessel disease in 12.5% and LAD culprit lesions in 25%. Septal E/E’ had a good correlation with LVEDP (Spearman's rho 0.603,p=0.001). The lateral E/E’ also had a good correlation with LVEDP (Spearman's rho 0.548,p=0.002). In a multivariate analysis for the predictors of elevated LVEDP(≥16 mmHg) incorporating E velocity, E/A ratio, deceleration time (DT) and septal and lateral E/E's, the septal E/E’ was the only independent predictor (OR = 11.9(95%CI 9.4-14.0), p=.047). A septal E/E’ cutoff of 15 identified 5/12 cases of LVEDP >16 mmHg whilst an E/E’ cutoff identified 10/12 cases of LVEDP >16 mmHg. Conclusions: Septal E/E’ ratio is a valid non-invasive assessment of elevated filling pressures in patients with NSTEMI.