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Abstract
Dobutamine stress transthoracic echo cardiography has become well established as a diagnostic modality for the non-invasive assessment of coronary artery disease and risk stratification especially in patients with vascular, orthopaedic, neurological or other medical problems. If the transthoracic echocardiographic studies are technically inadequate, then transesophageal approach will be of choice. The aim of the present work was to correlate dobutamine stress transesophageal echocardiography with coronary lesion severity as determined by quantitative coronary angiography in order to detect coronary artery disease. The aim is to show whether improvement in image quality by transesophageal echo cardiography will translate into improved sensitivity and specificity. The study was carried out in 40 patients, 9 of them were females, with a mean age of 49.1 ± 7.1 years suffering from or suspected to have coronary artery disease. All the patients had no evidence of cardiomyopathy, recent myocardial infarction, unstable angina, uncontrolled systemic hypertension, congestive heart failure, severe aortic stenosis, complex ventricular ectopy or contraindication for transesophageal echocardiography, dobutamine infusion and cardiac catheterization. 26 of the patients were functional class II while 14 patients were functional class III. All the patients were on nitrates and calcium channel blockers but only 12 of them were on selective B-blockers. All the patients stopped medications ~ 12 hours before the test. Every patient was subjected to thorough history taking, full clinical examination, resting ECG, coronary angiography and dobutamine stress transesophageal echocardiography. 21 patients had a decrease in systolic blood pressure after dobutamine infusion but it was significant in only 9 of them (decrease in systolic blood pressure equal to or more than 30 mmHg or to a level less than 100mmHg). No cardiac or non cardiac complications appeared during dobutamine infusion. 10 patients reached the target heart rate during the test and the mean peak heart rate was 130.9 ± 17.7 beat/minute. At rest before dobutamine infusion, 19 patients had a normal wall motion while the others showed wall motion abnormality by transesophageal echo cardiography with or without definite segmental distribution. All the patients included in the study showed a new segmental wall motion abnormality giving definite new segmental distribution (100% sensitivity), in the form of hypokinesia, dyskinesia or biphasic response after dobutamine infusion. As detected by coronary angiography, 8 patients had a single vessel disease, 16 patients had two vessels disease, 12 patients had three vessels disease while 4 patients had a left main coronary artery lesion. The left anterior descending artery system was affected in 29 patients, 28 of them were detected by dobutamine stress trans esophageal echo cardiography. The circumflex system was affected in 33 patients, 31 of them were detected by the dobutamine stress while the right coronary artery system was affected in 23 patients, 18 of them were detected by dobutamine stress. Although it seems that a lesion in the left anterior descending system could be detected easier than in circumflex and right coronary artery system, this difference was found to be statistically insignificant. Also there was no statistical significant difference between the ability of the dobutamine stress transesophageal echocardiography to predict the site of lesion in the coronary vessels in patients with multi vessels and single vessel disease. It was detected that patients with normal wall motion at rest have not a higher propensity for demonstrating new segmental wall motion abnormality after dobutamine infusion more than patients with wall motion abnormality at rest. Also it seems that there is no significant difference between patients with stenosis 2:: 90% and patients with stenosis 700/0--89% as regard detection of segmental wall motion abnormality before and after dobutamine infusion. Thus, the semi-mvasrve, non exercise dobutamine stress transesophageal two dimensional echocardiography must be more widely used as a useful alternative to conventional stress testing especially ill patients with suboptimal transthoracic echocardiographic images.