Endocardial Border Delineation during Dobutamine Infusion Using Contrast Echocardiography

BACKGROUND: A significant percentage of pharmacologic stress echocardiograms produce suboptimal images despite the use of second harmonic imaging. Intravenous continuous infusion of myocardial ultrasound contrast may enhance endocardial border delineation during dobutamine-atropine stress echocardiography (DASE), improving wall-motion analysis. PATIENTS AND METHODS: We prospectively studied 68 patients (41 males and 27 females), mean age 58 years, with DASE during intravenous infusion of contrast using second harmonic imaging. Dobutamine was infused in scalar doses of 5 microg/kg/min to 40 microg/kg/min, and atropine was administered in doses of up to 1 mg. We diluted 0.1 mL of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles into 80 mL of saline solution, which was used for continuous intravenous infusion. Blinded reviewers used a 16-segment model at rest and peak DASE to analyze segmental wall delineation in two sets of images for each patient, with and without contrast. An endocardial delineation score of 0-3 (nondelineated to excellent delineation) was given to each segment. An endocardial delineation score index (EDSI), the number of endocardial delineation scores for each set of images divided by 16, was created. RESULTS: The analysis of the mean EDSI for the 2176 segments was 1.46 (+/- 0.43) at rest and 1.30 (+/- 0.48) at peak for noncontrast images and 2.22 (+/- 0.52) and 2.29 (+/- 0.52) for contrast images. Complete left ventricle opacification was obtained in all patients, with a mean dose of 4 mL/min, although in 15 (22%) patients, signs of apical bubble destruction occurred. There were 1768 (81%) of 2176 segments delineated without contrast enhancement and 2057 (95%) of 2176 with enhancement (P < 0.05). CONCLUSION: Continuous infusion of myocardial ultrasound contrast improves endocardial border delineation using second harmonic imaging in patients undergoing DASE.