The significance of E/E′ to detect coronary artery disease during dobutamine stress echocardiography

To determine how the left ventricular diastolic filling pressure determined by E/E′ during dobutamine stress echocardiographic (DSE) by tissue Doppler Imaging (TDI) is affected by the presence and the severity of coronary artery disease (CAD) among patients with stable angina pectoris and also its relation to inducible ischemia. This study comprises 60 patients with suspected angina pectoris. All subjects were examined with DSE and TDI to assess resting mean E/E′ at peak stress, E/E′ change and E/E′ index. Coronary angiography was performed within 1 month. Coronary angiography revealed CAD in 38 patients (CAD group) while the remaining 22 patients formed the non-CAD group. There is a significant decrease of peak E′, S′ and increase peak E/E′ in CAD group during stress compared to non-CAD group (P < 0.01, P < 0.05 and P < 0.001, respectively). Thirty-two patients with inducible ischemia during stress had higher peak E/E′, E/E′ index compared to 28 patients with non-inducible ischemia. Receiver operating curve analysis showed an optimal cut-off value of peak E/E′, E/E′ change, E/E′ index (>4.11, >0.9 and >0.8, respectively) for the presence of CAD (area under curve 0.91, 0.93 and 0.88, respectively P < 0.001 for all). Sensitivities for detection of CAD were 94.7%, 84.2% and 89.5% and specificity was 90.9%, 72.7% and 74.7%, respectively. Peak E/E′, E/E′ index increased proportionally with the number of stenotic vessels (r = 0.89 and 0.76, respectively, P < 0.001). During DSE the changes of mean E/E′ ratio are associated with inducible ischemia, the presence of CAD and the extent of CAD. So, E/E′ can be used as objective evidence during DSE.