Collateral circulation following repeated distal embolization of the hepatic artery in pigs.

The distal hepatic arteries of eight pigs were embolized weekly with nondegradable microparticles. Hepatic angiograms were obtained before and after each embolization. One week after the last embolization Microfil was injected into the arterial and portal vascular beds of the liver prior to sacrifice. This study reveals that extensive collateral circulation develops after both primary and repeat embolization. After a third embolization in four of the pigs, the hepatic arterial circulation was almost totally abolished in two pigs with resulting extensive liver necrosis. An intact portal circulation is not sufficient to prevent infarction in dearterialized liver parenchyma.