Arterial parameters under echo contrast enhancement

Abstract

Objective: BY963 is a newly developed transpulmonary echo contrast agent that is currently being evaluated in phase II and III trials. The present paper investigates the influence of BY963 on commonly used quantitative Doppler flow velocity parameters. Methods: We gave intravenous injections of 1 ml (0.03 ml/kg) and 2.5 ml (0.08 ml/kg) of BY963 to five sedated male dogs with a body weight of (mean ± S.D.) 34 ± 2 kg. Peak systolic ( V max) and time-averaged maximum flow ( V tave-max) velocities were determined in the main renal and iliac arteries. The velocity measurements were carried out before administration of the contrast agent, during the contrast enhancement with 1 ml and 2.5 ml doses of BY963, respectively, and after the subsidence of contrast enhancement. The angle of insonation was kept constant. Additionally, one-lead-electrocardiographic recordings were monitored to assess the heart rate. Results: In the renal artery, V max increased from 90 ± 12 to 122 ± 21 cm/s ( P < 0.05), and V tave-max increased from 44 ± 8 to 54 + 10 cm/s ( P < 0.05) after the 1 ml dose of BY963. V max and V tave-max increased further to 130 ± 17 and to 59 ± 13 cm/s (not significant, NS), respectively, following the 2.5 ml dose of BY963. The heart rate remained unchanged. In the iliac artery, Vmax increased from 82 ± 15 to 103 ± 25 cm/s ( P < 0.05) and V tave-max from 13 ± 3 to 17 ± 5 cm/s ( P < 0.05) following a 1 ml dose of BY963. After the 2.5 ml dose, V max and V tave-max increased further to 108 ± 39 and to 19 ± 6 cm/s, respectively (NS). Reducing the Doppler gain on contrast-enhanced spectral analysis, the displayed velocities decreased to near baseline values. After the subsidence of the contrast enhancement, all flow velocity parameters returned to baseline values. Conclusion: The results of this study show that BY963 causes an increase in displayed maximum flow velocity of about 25–30% that has to be taken into account when quantitative maximum Doppler spectral parameters are being compared before and during echo contrast injection.