IMPROVED DOPPLER SIGNAL INTENSITY IN CORONARY-ARTERIES AFTER INTRAVENOUS PERIPHERAL INJECTION OF A LUNG-CROSSING CONTRAST AGENT (SHU-508A)

Objectives. We tested the hypothesis that SHU 508A, a new lung-crossin g contrast agent capable of increasing the Doppler signal to noise rat io in the right heart as well as left heart cavities after intravenous injection, could increase Doppler signal intensity in coronary arteri es, thus improving the feasibility and quality of transesophageal Dopp ler echocardiographic evaluation of coronary blood flow velocity. Back ground. Coronary blood flow velocity can be evaluated by transesophage al Doppler echocardiography. However, an adequate Doppler tracing is o btainable in a relatively low percent of patients. Methods. Transesoph ageal Doppler echocardiography of coronary arteries was performed in 3 5 patients before and after SHU 508A injection at four different dosag es (200 mg/ml in 5 ml, 200 mg/ml in 10 ml, 300 mg/ml in 5 mi and 300 m g/ml in 10 ml). Color Doppler mapping of coronary flow and pulsed wave Doppler measurement of coronary blood flow velocity were attempted in all patients. Results. Color Doppler flow mapping of 105 evaluated co ronary segments (left main, left anterior descending and circumflex in 35 patients) was not detectable or was weak in 88% of patients before and 33% of patients after echo contrast injection (p < 0.0001); it wa s optimal (that is, well delineated with complete flow mapping of the explored vessel) in only 11% of patients before and 67% after echo con trast injection (p < 0.0001). In addition, pulsed wave Doppler signal quality improved after echo contrast injection: Pulsed wave Doppler re cording of coronary blood flow velocity was not obtainable or was weak in 78% of cases before and 34% after echo contrast injection (p < 0.0 001); pulsed wave Doppler recording of coronary blood flow velocity wa s optimal (that is, there was a complete and well defined outline of d iastolic coronary blood flow velocity in 23% of cases before and 66% a fter echo contrast injection [p < 0.0001]. Both length and width of co lor Doppler mapping in the left anterior descending coronary artery in creased after SHU 508A injection (from 5.75 +/- 5.32 and 1.51 +/- 1.17 to 17.04 +/- 8.76 and 4.21 +/- 1.78 mm, respectively, mean +/- SD, p < 0.0001). Conclusions. The feasibility and quality of recording coron ary blood flow, velocity by transesophageal Doppler echocardiography a re considerably improved by intravenous injection of SHU 508A. The imp roved feasibility of this new semi-invasive method for evaluating coro nary blood flow velocity and flow reserve can considerably increase it s research and clinical utilization.