Isolated hepatic perfusion (IHP) allows loco-regional administration of high drug doses for cancer treatment. Minimally invasive endovascular occlusion techniques can be used for IHP, but control of leakage remains a major drawback. We hypothesized that the increased intraabdominal pressure generated by a CO(2)-pneumoperitoneum (PP) can reduce the leakage rate of hypoxic endovascular IHP by mechanical compression of the capillary beds connecting the liver to the systemic circulation.
IHP was performed on adult pigs through laparotomy using a fenestrated double balloon-catheter placed into the retrohepatic vena cava to collect the hepatic outflow which was reinfused into the hepatic artery through an extracorporeal circulation system. Each pig underwent IHP during four consecutive phases: abdomen open (Phase I), abdomen closed under a 15 and 20 mmHg pneumoperitoneum (Phase II and III, respectively) and abdomen re-opened (Phase IV). The leakage rate from the liver to the systemic circulation was continuously monitored using a nuclear medicine technique. The systemic arterial pressure, the IHP inflow and outflow pressures and the flow rate were recorded.
Leakage from the hepatic extracorporeal circulation to the systemic circulation occurred in all animals during Phase I. Under PP (Phases II and III), two leakage profiles were observed: (1) a major increase of the leakage rate in two animals with a high differential pressure (>50 mmHg) between the IHP inflow and the systemic pressures; (2) no change or a decrease of the leakage rate in the other three animals who had a low or negative differential pressure (<30 mmHg). Leakage was undetectable in all animals after exsufflation of the PP (Phase IV).
IHP under PP is feasible. Leakage is not reduced during PP. A high gradient between the IHP inflow and the systemic pressure increases systemic leakage during PP. Upon release of the PP, the leakage is most likely redirected towards the volume depleted low resistance portal territory.