Experimental studies on the circulatory dynamics of intrahepatic tumor blood supply

Abstract

Studies on the circulatory perfusion of liver tumor implants in rats indicated that the tumors, when small, are nourished by both hepatic artery and portal vein blood. As the tumors grow larger, the arterial system becomes predominant, although portal vessels appear to terminate near the edges of the tumors. When blood flow through the portal system is acutely interrupted, the immediate reaction is that of a decreased relative perfusion of the tumors via the arterial system. A probable shunting of blood through the arterioles to the liver occurs. When blood flow through the hepatic artery is acutely interrupted, there appears to be little change in the distribution of portal blood to the tumor or liver. However, in about half of the rats studied by microcirculatory techniques, filling of the tumor plexus via the portal system was observed. When vasoactive drugs, both constrictors and dilators, were administered arterially, a decreased arterial perfusion of the tumors occurred. This change appeared to involve only the small arterial vessels.

Abnormal Response of Tumor Vasculature to Vasoactive Drugs23

“…In pharmacoangiography, vasoactive drugs have been employed to amplify the radiographic contrast between normal and cancerous tissues (4)(5)(6)(7)(8). In radiation therapy such drugs have been investigated in hopes of increasing the oxygen tension within tumors during treatments (9)(10)(11)(12)(13). In chemotherapy, such drugs may help by preferentially channeling cytotoxic drugs into the tumor tissue (13).…”

Comparison between intravenous and intraarterial contrast injections for dynamic 3D MRI of liver tumors in the VX2 rabbit model

“…Hepatic arterial catheter placement is currently widely used for therapeutic HCC interventions with bland or chemoembolization as well as radioembolization. Since 90 -100% of the HCC tumor blood supply originates from the hepatic artery, these interventions focus and concentrate delivery of therapeutic agents predominantly to the tumor (15). Thus, IA contrast agent injection would also concentrate the dose predominantly in the tumor.…”

“…Previous studies using a hybrid CT-angiography unit in the setting of catheter-directed angiography demonstrated that the addition of cross-sectional CT imaging during catheterdirected angiography improved sensitivity for detection of small HCC lesions (92%) compared to catheter-directed superselective digital subtraction angiography (DSA) alone (65%) (16). In addition, CT imaging during catheterdirected angiography led to repositioning the catheter (15,16), and ultimately altered therapy in a subset of patients (16,17). Thus, the use of a hybrid X-ray MR angiography (MRA) unit in the setting of catheter-directed angiography may offer the same advantages provided by hybrid CT-angiography units.…”

Redistribution of blood flow in experimental hepatic tumours with noradrenaline and propranolol

“…Hafstrom and co-workers (1980b) have described small increases in the T/N ratio in rat liver tumours after noradrenaline (0.23 to 0.29 and 1.4 to 2.9) and subjective evidence has been presented of large intrahepatic ratio's in humans with the drug (Grady et al, 1981). However, the use of noradrenaline has also been shown by Ackerman (1972) to have no effect on the T/N ratio in rat liver tumours and it does not alter access of blood flow to the internal tumour circulation (Ackerman & Hechmer, 1977). In addition, Young and co-workers (1979) have shown in both rats and rabbits substantial reductions in the T/N ratio with noradrenaline infusion with a dose dependency showing greater decline with larger doses.…”