ARTERIOVENOUS SHUNTS IN PATIENTS WITH HEPATIC-TUMORS

The study aimed to investigate the influence of tumor type, tumor size , tumor vascularity and treatment on arteriovenous shunts between the liver and lungs in patients with hepatic cancer. Methods: Our previous assessment of the degrees of lung shunting using intra-arterial Tc-99 m-macroaggregated albumin in 125 patients with hepatocellular carcinom a (HCC) was extended to include 377 patients with HCC and 25 patients with colorectal liver metastases. Patients were given 111 MBq (3 mCi) of Tc-99m-macroaggregated albumin during hepatic angiography. The lung s and the liver were localized as regions of interest on the digitized gamma scintigraphic image. The total counts taken over the lungs divi ded by the total counts taken over both the lungs and the liver gave t he percentage of lung shunting. Tumor size was measured by computerize d tomography or ultrasound scan. Tumor vascularity was assessed based on the degree of neovascularization. Linear regression and Wilcoxon ra nk test were used for statistical analysis. Results: Patients with HCC had a higher median (7.6%) and a wider range (<1-75.4%) of percentage s of lung shunting when compared with those with colorectal liver meta stases (median, 4.7%; range, <1-23.9%). The lung shunting correlated w ith the tumor size in the 377 patients with HCC (r = 0.359; p < 0.0001 ). Excluding one outlier, we found a similar correlation in 24 patient s with colorectal metastases (r = 0.686; p < 0.0001). In HCC, the mean lung shunting increased with increasing tumor size, up to 15 cm, and then remained almost unchanged, up to a size of >20 cm. The mean lung shunting also increased with increasing vascularity grades, as assesse d by hepatic angiography. The difference between any two vascularity g rades was statistically significant (p = 0.0001-0.0148). Similar analy sis by subgroups in colorectal liver metastases was impossible because of the small number of patients. Lung shunting decreased in HCC patie nts after the tumors were treated, but it might increase or decrease w hen the disease recurs. Conclusion: The lung shunting was influenced b y the type, size and vascularity of the hepatic tumor. The change in l ung shunting with the status of the tumor after treatment further sugg ests a neoplastic nature of the blood vessels involved in the arteriov enous shunt.