Evaluation of the effect of total isolated liver perfusion on hepatic circulation and the feasibility of a percutaneous approach in a pig model.
In fifteen pigs undergoing total isolated liver perfusion, the unilateral common femoral artery, bilateral common femoral veins and right jugular vein were exposed through a cut-down incision, and sheaths (8 Fr., 12 Fr., 9 Fr. and 9 Fr.) were individually inserted into each blood vessel. Catheters were placed in the proper hepatic artery and inferior vena cava (IVC). The portal vein branch was punctured with a percutaneous transhepatic cholangiodrainage needle under X-ray guidance, and a 12 Fr. sheath was inserted. Balloon catheters, which we had developed in-house, were then inserted into the portal vein trunk. These catheters have specially designed side arms to allow a strong flow and to maintain the pressure in the pump system low during withdrawal and return of the blood through the catheter. After systemic heparinization (120 U/kg), the balloons were used to occlude the proper hepatic vein and portal vein trunk. We used two methods to occlude the hepatic vein. The first was inflation of balloons in the infrahepatic and suprahepatic IVCs. The second was the use of an expandable metallic stent covered with a synthetic vascular prosthesis (covered EMS) in the IVC. The covered EMS indwelled in the IVC was improved to allow recovery.
In the first occlusion method, to maintain blood pressure, blood was withdrawn from the infrahepatic IVC with one rotary pump and returned to the jugular vein through the sheath using another rotary pump. Blood was withdrawn from the superior mesenteric vein and returned to the jugular vein through the sheath employing a rotary pump.
In both methods, blood was withdrawn from the portal vein using one rotary pump (60 ml/min) and returned to the proper hepatic artery (60 ml/min) with contrast medium through the balloon catheter via another rotary pump. Perfusion was carried out for 30 min.
The seven pigs investigated using the first balloon catheter method showed hemodynamic instability, making it impossible to assess the effect of the new isolated liver perfusion system. The remaining eight pigs, investigated using the second method employing the covered EMS, were hemodynamically stable. During complete occlusion of the hepatic veins, contrast medium was observed to drain in a reverse direction into the portal vein in three pigs. Collateral vessels could not be seen.
Total isolated perfusion accomplished by occlusion of the IVC and portal vein in combination with aspiration applied to the portal circulation results in rapid and extensive arterioportal shunting without visualization of collateral vessels. Although this percutaneous approach is technically feasible, its hemodynamic safety must be evaluated before clinical application is attempted.
● M. Satake ●
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