平木 隆夫

To clarify the incidence, background, and progress of hepatic infarction following interventional procedures, cases of hepatic infarction following interventional procedures at our department during the last decade were identified by reviewing the clinical records of 1982 abdominal angiography and interventional procedures and records of abdominal CT. Nine episodes (0.5%) in 8 patients were identified as hepatic infarction following an interventional procedure. Five episodes were preceded by embolization of the hepatic or celiac artery at emergency angiography for postoperative bleeding with hemorrhagic shock. Three episodes followed the elected interventional procedure for hepatocellular carcinoma, and the remaining episode occurred after 12 months of chemoinfusion through an indwelling catheter in the hepatic artery and portal vein. Hepatic arterial occlusion in all episodes and portal venous flow abnormality in 5 episodes were observed on angiography. Four patients whose liver function was initially impaired died of hepatic infarction, although the extent of the disease on CT did not appear to be related to the mortality. Multiple risk factors, including arterial insufficiency, were observed in each patient. The incidence of hepatic infarction following interventional procedures in this series was low but sometimes fatal, and occurred most frequently in emergency embolization in hemorrhagic shock.

Hepatic outflow obstruction created by balloon occlusion of the hepatic vein induces characteristic angiographic findings in the occluded area: prolonged enhancement on hepatogram followed by reversed portal opacification on the hepatic arteriogram and perfusion defect on the arterial portogram. The following induced hepatic hemodynamic changes are suggested: hepatic arterial flow increases, and the portal vein acts as a draining vein with slow reversed flow. These unique hemodynamic changes enhance the effect of hepatic interventional therapies. In transcatheter arterial infusion, increasing hepatic arterial flow and absence of portal inflow can bring about a high concentration of drugs, the presence of which is greatly protracted due to outflow blockage. In transcatheter arterial chemoembolization, reversed portal flow can allow portal embolization in addition to arterial embolization. In microwave coagulation therapy and radiofrequency ablation therapy, decreasing portal flow can cause larger areas of coagulation. Further, the technique of hepatic venous occlusion has potential therapeutic applications.

The present study was performed to clarify the effect of hypertonic saline infusion into the lung parenchyma on radiofrequency ablation (RFA) of the lungs. A total of 20 ablation zones were created in 3 pigs. The ablation zones were divided into 3 groups. Group 1 (n6) consisted of ablation zones created by applying smaller radiofrequency (RF) power without saline infusion;group 2 (n5) zones were created by applying greater RF power without saline infusion;and group 3 (n9) zones were created by applying greater RF power with saline infusion. The techniques of saline infusion included administration of hypertonic saline 1ml before RFA, followed by continuous administration at a rate of 1ml/min during the first 2min after the initiation of RFA. The ablation parameters and coagulation necrosis volumes were compared among the groups. Group 3 had a tendency toward smaller mean impedance than group 1 (p0.059) and group 2 (p0.053). Group 3 showed significantly longer RF application time than group 2 (p0.004) and significantly greater maximum RF power than group 1 (p0.001) and group 2 (p0.004). Group 3 showed significantly larger coagulation necrosis volume (mean, 1,421mm3) than group 2 (mean, 858mm3, p0.039) and had a tendency toward larger necrosis volume than group 1 (mean, 878mm3, p0.077). Although this small study had limited statistical power, hypertonic saline infusion during RFA appeared to enlarge coagulation necrosis of the lung parenchyma.