The value of E/Em ratio in the estimation of left ventricular filling pressures: impact of acute load reduction: a comparative simultaneous echocardiographic and catheterization study.

BACKGROUND

The ratio of the early transmitral flow velocity to the early diastolic tissue velocity (E/Em) has been suggested as a reliable estimate of left ventricular diastolic pressures (LVDP). However, the evidence regarding the ability of E/Em to detect LVDP changes is relatively equivocal. Our aim was to evaluate the validity of the ratio following acute load reduction.

METHODS AND RESULTS

68 consecutive patients referred for coronary angiography underwent LV catheterization and echocardiography simultaneously. Doppler signals of transmitral flow and spectral TD signals at the level of the mitral annulus were obtained before and directly after intravenous administration of nitroglycerin (NTG). The predictive ability of E/Em to identify elevated LVDP was modest (area under curve=0.71 ± 0.08, p<0.01). The index was more strongly associated with LVDP in patients with reduced ejection fraction (EF)<55% (r=0.68; p<0.01) than in patients with normal EF. Following NTG, E/Em lacked any predictive potential for elevated LVDP whereas changes LVDP could not be reliably tracked using E/Em.

CONCLUSION

The predictive capacity of E/Em for elevated LVDP was weak and declined significantly following acute reduction in LV load. Changes in LVDP were not reliably predicted by E/Em. The current findings derived from a real-world patient population with relatively high filling pressures indicate that E/Em may not be sufficiently robust to be employed as a single non-invasive estimate of LVDP nor for monitoring load reducing medical therapy.