Peak early diastolic velocity rather than pressure half-time is the best index of mechanical prosthetic mitral valve function

Abstract

Reliable screening of mechanical prosthetic mitral valve (PMV) dysfunction by transthoracic echocardiography (TTE) is mandatory because transesophageal echocardiography (TEE) cannot be routinely used. However, acoustic shadowing seriously hampers detection of PMV dysfunction with TTE, particularly regurgitation. To identify TTE indexes that can detect PMV dysfunction (regurgitation or obstruction), 134 patients (age 60 ± 12 years, 64 men) with PMV who underwent TTE and TEE within 3 ± 5 days were assessed. There were 73 normal and 61 dysfunctional valves (40 regurgitant, 21 obstructive). By multivariate analysis, peak E velocity was the best predictor of a dysfunctional valve. Both peak E velocity (E ≥1.9 m/s; sensitivity 92%, specificity 78%) and the ratio of velocity-time integrals of flow through the prosthesis to that of the left ventricular outflow (VTI pmv/VTI lvo ≥2.2; sensitivity 91%, specificity 74%) were successful in detecting PMV dysfunction. Although pressure half-time (PHT) readily identified PMV obstruction, it did not detect regurgitation. Logistic models including peak E velocity and VTI pmv/VTI lvo or PHT were equally successful in detecting PMV dysfunction. However, all 3 variables were needed to best distinguish among normal, obstructed, and regurgitant valves. A peak E velocity ≥1.9 m/s and VTI pmv/VTI lvo ratio ≥2.2 predicted valve regurgitation in 83% of valves when PHT was <130 ms, and valve stenosis in 95% when PHT was >130 ms. Importantly, a peak E velocity <1.9 m/s, VTI pmv/VTI lvo ratio <2.2, and a PHT <130 ms had a predictive accuracy for a normal valve of 98%. Thus, TTE Doppler indexes can be used as screening parameters of PMV dysfunction and help select patients for further diagnostic evaluation with TEE.