Hepatic arterial haemodynamics changes following intra-arterial angiotensin II infusion: duplex/colour Doppler sonography

Abstract

Previous studies have shown that the delivery of cytotoxic microspheres to liver tumours may be improved by manipulating the tumour to normal liver blood flow ratio using angiotensin II (AT-II). The optimization of this targeting requires the assessment of the temporal blood flow changes induced by agents such as AT-II. Duplex/colour Doppler sonography (DCDS) was evaluated as a means of studying the effects of AT-II infusion on hepatic arterial blood flow (HABF) and arterial resistance in patients with colorectal liver metastases. HABF was measured continuously in six patients with colorectal liver metastases using DCDS before, during and after an infusion of AT-II (15 micrograms in 3 ml of saline over 90 s) via a hepatic artery catheter. The baseline level of HABF was 320 +/- 87 ml/min (mean +/- S.D.), and this was reduced by 70-76% within 30 s of the start of AT-II infusion. HABF recovered rapidly from the end of the infusion, and increased by up to 20% above the baseline for approximately 2 min. Arterial resistance showed reciprocal changes in all cases. These changes were both quantitatively and qualitatively similar to intra-operative measurements previously performed in the same patients using a standard intra-operative flowmeter. The degree of concordance obtained from the intra- and post-operative measurements confirms the effectiveness of DCDS in assessing the temporal changes in hepatic arterial blood flow caused by AT-II. Prior to the start of therapy, the evaluation of vasoconstrictor agents should be carried out in individual patients to predict response, in order to establish the optimal phase for the injection of cytotoxic microspheres.