Temporary portocaval shunt during liver transplantation with vena cava preservation. Results of a prospective randomized study. Randomized trial comparing pulmonary alterations after conventional with venovenous bypass versus piggyback liver transplantation. Piggy-back versus conventional technique in liver transplantation: report of a randomized trial.
This study aims to determine whether the use of a temporary portocaval shunt (PCS) improves hemodynamic and metabolic evolution during orthotopic liver transplantation (OLT). Preservation of the vena cava during OLT has gained wide acceptance. However, benefits of adding a temporary PCS to the piggyback technique during the anhepatic phase in patients with cirrhosis have not been shown. Eighty patients with cirrhosis were studied prospectively. They were randomly distributed into two groups: patients with a temporary PCS (n = 40) and those without a PCS (n = 40). In all cases, the piggyback technique was used. Hemodynamic profiles and biochemical data during OLT and clinical evolution after OLT were evaluated. Preoperative data were similar in both groups. Surgical time also was similar (403 +/- 77 v 387 +/- 56 minutes; P = .3). Red blood cell requirements were lower in the PCS group (2.3 +/- 2.5 v 3.3 +/- 2.9 units), although differences were not significant. In the PCS group, 45% of patients did not need red blood cell transfusion, whereas in the other group, only 22% were not administered a transfusion (P = .03). During the anhepatic phase, the decrease in cardiac output was lower in the PCS group (-9.6% v -19%; P = .05), whereas diuresis during the anhepatic phase was greater in the PCS group (3.6 +/- 2.97 v 2.1 +/- 1.38 mL/kg/h; P = .005). There were no differences in liver biochemical parameters during the first 3 postoperative days. Nevertheless, creatinine levels increased significantly during this period only in the no-PCS group. The use of a temporary PCS during OLT improves hemodynamic status, reduces intraoperative transfusion requirements, and preserves renal function during and after OLT. During the anhepatic phase of conventional liver transplantation (LT), the inferior vena cava (IVC) is cross-clamped and venovenous bypass (VVB) is usually indicated for diversion of IVC and portal blood flow. VVB can theoretically lead to pulmonary complications due to the contact of the blood with the surfaces of the circuit. In the piggyback method, preservation of the IVC avoids VVB. The aim of this study is to compare pulmonary alterations after conventional with VVB versus piggyback LT. Sixty-seven patients were randomized for conventional VVB (n = 34) or piggyback (n = 33) LT. Pulmonary static compliance (C(st)) and Pa(O2)/F(IO2) ratio were measured pre- and post-LT. Chest X-rays were obtained daily from the 1st to the 5th postoperative day. Pre- and post-LT C(st) were 73.4 +/- 36.0 mL/cm H(2)O and 59.7 +/- 22.0 mL/cm H(2)O in the conventional group and 69.1 +/- 20.0 mL/cm H(2)O and 58.7 +/- 27.1 mL/cmH(2)O in the piggyback group. The difference between the two groups was not significant (P =.702). C(st) significantly decreased after LT (P =.008). The pre- and post-LT Pa(O2)/F(IO2) were 455.6 +/- 126.6 mm Hg and 463.1 +/- 105.9 mm Hg in the conventional group and 468.9 +/- 114.1 mm Hg and 483.3 +/- 119.8 mm Hg in the piggyback group. The difference among the two groups was not significant (P = 0.331). There was no significant difference after LT (P =.382). Upon the radiological evaluation, piggyback group presented a higher frequency of pulmonary infiltrates (80.6% vs. 50.0%; P =.025). In conclusion, piggyback LT recipients have a higher rate of pulmonary infiltrates when compared to those operated upon using the conventional VVB method. Liver transplantation with preservation of the recipient vena cava (the "piggy-back" technique) has been proposed as an alternative to the traditional method. We performed a randomized study on 39 cirrhotic patients, 20 who underwent the piggy-back technique (group 1) and 19 the traditional method using venovenous bypass (group 2) to evaluate the feasibility and true advantages of the piggy-back technique compared to the traditional method. Two patients were switched to the conventional technique due to the presence of a caudate lobe embracing the vena cava in one patient and a caval lesion in the other. Statistically significant differences between the two groups were only found for the warm ischemia time (48.5 +/- 13 min for piggy-back vs 60 +/- 12 min for the conventional method) and for renal failure (zero cases in group 1 vs four cases in group 2). We therefore believe that liver transplantation with the piggy-back technique can easily be performed in almost all cases, and that only a few, specific situations, such as a very enlarged caudate lobe, do not justify its routine use.
There is currently no evidence to recommend or refute the use of piggy-back method of liver transplantation.