Evaluation of (1) the effect of total isolated liver perfusion on hepatic circulation and (2) the feasibility of a percutaneous approach in a pig model.
In 10 pigs undergoing total isolated liver perfusion (Fig. 1), the unilateral common femoral artery, bilateral common femoral veins, and the right jugular vein were exposed through a cut-down incision, and sheaths (8 Fr., 12 Fr., 9 Fr., and 9 Fr., respectively) were inserted into them. Catheters were placed in the proper hepatic artery and the inferior vena cava (IVC). The portal vein branch was punctured with a PTCD needle under X-ray guidance, and a 12 Fr. sheath was inserted into it. Balloon catheters, that had been developed in-house, were then inserted into the portal vein trunk. These catheters have specially designed side arms to allow a high flow rate and to maintain a low pressure in the pump system during withdrawal and return of the blood through the catheter. After systemic heparinization (120 U/kg), the balloons were inflated to occlude the proper hepatic vein and the portal vein trunk. The hepatic vein was occluded by one of the 2 methods: first, inflation of the balloons in the infrahepatic and suprahepatic IVC and second, the placement of an expandable metallic stent covered with a synthetic vascular prosthesis (covered EMS) in the IVC.
To maintain the blood pressure, blood was withdrawn from the infrahepatic IVC using a rotary pump and was returned to the jugular vein through the sheath using another rotary pump in the first methods; in the second method, blood was withdrawn from the superior mesenteric vein and was returned to the jugular vein through the sheath by employing a rotary pump.
In both methods, blood was withdrawn from the portal vein using one rotary pump (rate, 60 ml/min) and was returned to the proper hepatic artery (rate, 60 ml/min) along with a contrast medium through the balloon catheter via another rotary pump. Perfusion was carried out for 30 min.
The 7 pigs in whom the hepatic vein was occluded by the first method showed hemodynamic instability, making it impossible to assess the effect of the new isolated liver perfusion system. The remaining 3 pigs in whom the second method was used for hepatic vein occlusion, i.e., using the covered EMS, were hemodynamically stable. During complete occlusion of the hepatic veins, the contrast medium was observed to drain in a reverse direction into the portal vein in all 3 pigs. Collateral vessels could not be visualized.
Total isolated perfusion accomplished by occlusion of the IVC and the portal vein in combination with aspiration applied to the portal circulation results in rapid and extensive arterioportal shunting without visualization of the collateral vessels. This percutaneous approach is technically feasible; however, its hemodynamic safety must be evaluated before clinical application is attempted.
● M. Satake ●
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