Determination of Lesion Severity by Dobutamine Stress Echocardiography When Compared with Quantitative Coronary Angiography: A Retrospective Cohort Study

Exercise stress testing is done commonly for the detection of coronary artery disease (CAD). It is a noninvasive method for CAD detection. In certain patients where exercise testing is not possible, some other form of non-invasive stress testing is required. Out of various techniques which can induce ischemia, traditionally dobutamine stress echocardiography (DSE) has been relied up on. DSE can be done for detection and localization of CAD.

In this study, a retrospective cohort study was done in the patients who underwent both DSE and quantitative coronary angiogram (CAG). The study was carried out on various parameters: a) severity of CAD was correlated with the heart rate at which a positive DSE test is obtained; b) ability of DSE to detect coronary artery stenosis with a minimal lumen diameter <1 mm was evaluated; c) a new model of coronary artery distribution was utilized to determine the ability of dobutamine stress echocardiography (DSE) in detecting stenosis in individual coronary arteries.

A total number of 104 patients were identified who underwent both DSE and CAG. All of these patients were evaluated on the above mentioned parameters. Interpretation of echocardiograms was done using a modified 16-segment model. Incremental infusion of dobutamine was given in all these patients. Twodimensional echocardiograms were obtained: at rest, during low stress (low dose dobutamine), peak stress (peak dose dobutamine) and after stress (recovery). The data obtained was then analyzed for an overall sensitivity, specificity and accuracy of this technique in detection of CAD (diameter stenosis.50%).

DSE was found to have a high sensitivity and specificity for the detection and localization of CAD when compared with CAG. Dobutamine stress echocardiography is equally sensitive in detecting CAD in all the three major coronary artery distributions, especially by using the modified 16-segment model with areas of coronary artery distribution. Lesions where the minimal lumen diameter is <1 mm are more likely to be correctly identified by DSE. A multivessel CAD is more likely to be present when a DSE becomes positive at a heart rate.125 beats/min.