Liver transplantation by preservation of the caval flow with temporary porto-caval shunt or veno-venous bypass

Venovenous bypass in adult liver transplant recipients: A single-center observational case series

BACKGROUND

Very little information is currently available on the use and outcomes of venovenous bypass (VVB) in liver transplantation (LT) in adults in Australia. In this study, we explored the indications, intraoperative course, and postoperative outcomes of patients who underwent VVB in a high-volume LT unit.

METHODS

The study was a single-center, retrospective observational case series of adult patients who underwent VVB during LT at Austin Health in Melbourne, Australia between March 2008 and March 2022. Information on baseline preoperative status and intraoperative variables, including specific VVB characteristics as well as postoperative and VVB-related complications was collected. The lengths of intensive care unit and hospital stays as well as intraoperative and in-hospital mortality were recorded.

RESULTS

Of the 900 LTs performed at this center during the aforementioned 14-year period, 27 (3%) included a VVB procedure. VVB was performed electively in 16 of these 27 patients (59.3%) and as a rescue technique to control massive bleeding in the other 11 (40.1%). The median (interquartile range [IQR]) age of those who underwent VVB procedures was 48 (39-55) years; the median age was 56 (47-62) years in the non-VVB group (p<0.0001). The median model for end-stage liver disease (MELD) scores were similar between the two patient groups. Complete blood data was available for 622 non-VVB patients. Twenty-six VVB (96.3%) and 603 non-VVB (96.9%) patients required intraoperative blood transfusions. The median (IQR) number of units of packed red blood cells transfused was 7 (4.8-12.5) units in the VVB group compared to 3.0 units (1.0-6.0) in the non-VVB group (p<0.0001). Inpatient mortality was 18.5% and 1.1% for the VVB and non-VVB groups, respectively (p<0.0001). There were no significant differences in length of hospital stay or incidence of acute kidney injury, primary graft dysfunction, or long-term graft failure between the two groups. Patients in the VVB group experienced a higher rate of postoperative non-anastomotic biliary stricture compared to patients in the non-VVB group (33% and 7.9%, respectively; p = 0.0003).

CONCLUSIONS

VVB continues to play a vital role in LT. This case series highlights the heightened risk of major complications linked to VVB. However, the global transition to selective use of VVB underscores the urgent need for collaborative multi-center studies designed to address outstanding questions and parameters related to the safe implementation of this procedure.

Benefits of temporary portocaval shunt during orthotopic liver transplantation with vena cava preservation: A propensity score analysis

During orthotopic liver transplantation (OLT), clamping of the portal vein induces splanchnic venous congestion and accumulation of noxious compounds. These adverse effects could increase ischemia/reperfusion injury and subsequently the risk of graft dysfunction, especially for grafts harvested from extended criteria donors (ECDs). Temporary portocaval shunt (TPCS) could prevent these complications. Between 2002 and 2013, all OLTs performed in our center were retrospectively analyzed and a propensity score matching analysis was used to compare the effect of TPCS in 686 patients (343 in each group). Patients in the TPCS group required fewer intraoperative transfusions (median number of packed red blood cells-5 versus 6; P = 0.02; median number of fresh frozen plasma-5 versus 6; P = 0.02); had improvement of postoperative biological parameters (prothrombin time, Factor V, international normalized ratio, alkaline phosphatase, and gamma-glutamyltransferase levels); and showed significant reduction of biliary complications (4.7% versus 10.2%; P = 0.006). Survival analysis revealed that TPCS improved 3-month graft survival (94.2% versus 88.6%; P = 0.01) as well as longterm survival of elderly (ie, age > 70 years) donor grafts (P = 0.02). In conclusion, the use of TPCS should be recommended especially when considering an ECD graft. Liver Transplantation 23 174-183 2017 AASLD.

Caval reconstruction techniques in orthotopic liver transplantation

There are several caval reconstruction techniques currently in use for orthotopic liver transplantation. These include caval replacement or the conventional technique, performed with or without venovenous bypass, piggyback technique with anastomosis with two or three hepatic veins with or without cavotomy and modifications of the piggyback technique including end-to-side and side-to-side cavocaval anastomosis. There are few randomized controlled trials comparing the use of these techniques and our knowledge of their comparability is based on a few multi- and many single-center retrospective and prospective reviews. Although there are advantages and disadvantages for each technique, it is advisable that the surgeon perform the technique with which they have the most the experience and at which they are the most skilled as excellent outcomes can be obtained with any of the caval reconstruction options discussed.

Temporary portocaval shunt in orthotopic liver transplantation: need for a standardized approach?

Maintenance of portal and systemic venous return during the anhepatic phase of liver transplantation (LT) improves hemodynamic stability. With the piggyback technique, caval return is maintained; however, temporary clamping of the portal vein is still necessary. The use of a temporary portocaval shunt (TPCS) has been proposed to minimize the effect of portal venous interruption. The aim of this study was to perform a systematic review of the literature to determine whether there is evidence to support the routine use of a TPCS in LT. An electronic search of the literature from 1963 to 2007 was performed. A total of 4386 articles were identified, of which 8 met all the criteria and were included in the study. Because of the variability in reporting and the small number of studies, statistical comparison was not possible; however, a trend toward a shorter operative time, less blood product transfusion, and maintenance of higher mean arterial pressures during portal vein clamping was seen in patients with a TPCS. In conclusion, the available evidence, albeit scarce, supports the use of a TPCS in patients undergoing LT. A prospective randomized study of patients most likely to benefit from a TPCS is necessary to substantiate these findings.

Temporary porto-caval shunt utility during orthotopic liver transplantation

INTRODUCTION

In liver transplantation (OLT) a porto-caval shunt is a well-defined technique practiced by many surgeons in several centers.

METHODS

We considered 186 cadaveric OLT patients who underwent a cavo-cavostomy-type reconstruction; they were divided into two groups: those in whom we performed a porto-caval shunt (group A) and those in whose we did not (group B). We evaluated several variables: warm and total ischemia time, intraoperative blood and fresh frozen plasma transfusions, crystalloid and colloid requirements, blood loss, operative duration, hemodynamic intraoperative changes and diuresis, length of hospital stay, and creatinine values at days 1 and 2, and at discharge day.

RESULTS

Total and warm ischemic time differed significantly between the two groups. Infusion of blood, fresh frozen plasma, colloid, and crystalloid did not significantly differ. Blood loss was lower, and intraoperative diuresis was not significantly increased in group A subjects. Postoperative hospitalizations were 16.5 and 17.8 days and operative times, 504 and 611 minutes in the two groups. Both cardiac index and ejection fraction values during the anhepatic phase were significantly greater among group A than group B patients. PAD at the two phases was greater in group B. The PAS was significantly different only at reperfusion time. Creatinine values were significantly different at discharge. Better survival was shown for group A patients over group B subjects.

CONCLUSION

The results presented herein confirmed that a porto-caval shunt during OLT was a safe, useful expedient contributing to an improved hemodynamic status and a better time distribution in the various phases of liver transplantation.

Orthotopic Liver Transplantation With Vena Cava Preservation in Cirrhotic Patients: Is Systematic Temporary Portacaval Anastomosis a Justified Procedure?

INTRODUCTION

We evaluated the peri- and postoperative effects of the lack of a temporary portocaval anastomosis (TPCA) during orthotopic liver transplantation (OLT) in 84 patients with cirrhosis.

PATIENTS AND METHODS

From December 1996 to December 2002, 156 liver transplant recipients included (54%; 60 men and 24 women) of mean age 52 +/- 9 years with portal hypertension. In whom peri- and postoperative data were analyzed.

RESULTS

The median fall in mean arterial pressure upon vascular clamping and unclampings was 20 mm Hg (range 15 to 75), while the median duration of portal vein clamping was 77 minutes. The median amount of blood autotransfusion was 1100 mL (range 0 to 5400). The median number of red blood cell and fresh-frozen plasma units transfused were 5 and 6.5, respectively. The median intraoperative urinary output was 72 mL/h (range 11 to 221). Three patients (3.5%) presented a perioperative complication, but no perioperative death was observed. Six patients experienced an early postoperative complication (<10 days): five hemodynamic complications and one transient renal failure, which did not require hemodialysis. One patient (1%) died at 12 hours after OLT from acute pulmonary edema.

CONCLUSION

This study shows that systematic TPCA during OLT with preservation of the native retrohepatic vena cava in cirrhotic patients does not appear to be justified. In contrast, peri- and postoperative hemodynamic parameters as well as blood component requirements were comparable to those of the literature reporting OLT with straightforward TPCA.

Temporary portocaval shunt during liver transplantation with vena cava preservation. Results of a prospective randomized study

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.

Optimized veno-venous bypass with the affinity pump

Veno-venous bypass (VVBP) is increasingly used to avoid acute venous hypertension and low cardiac output after clamping the vena cava. Air embolism upon accidental decannulation of the inflow line and endothelial damage due to suction of the blood collecting cannula to the vessel wall are known complications specific to the currently used roller and centrifugal pumps, because they generate negative pressure at the inflow site of the pump. The Affinity pump has a unique chamber design with an occlusive segment, that collapses in low filling states preventing negative pressure at the inflow site of the pump chamber. This device was tested for VVBP in three pigs (each weighing 52.3 +/- 5.1 kg) with hepatic vascular exclusion. Blood was pumped from the femoral and portal veins to the external jugular vein and perfusion was maintained for 6 hours. The hemodynamic state of the animals was assessed by recording heart rate; systolic, mean arterial, and diastolic pressure; as well as central venous pressure. Mean pump flow during the experiment was 1,629.3 +/- 372.2 ml/min. After clamping, the inflow line of the pump mean arterial pressure significantly decreased (from 69.5 +/- 4.4 to 43.1 +/- 3.5 mm Hg), and mean pressure in the femoral vein increased significantly (from 16.1 +/- 2.6 to 26.8 +/- 5.9 mm Hg), whereas the mean pressure in the internal jugular vein did not significantly change (from 6.0 +/- 1.7 to 5.0 +/- 2.1 mm Hg). There was no suction by the blood collecting cannula on the vessel wall, and neither bubbles nor air emboli were detected and no operator intervention was needed. In conclusion, the Affinity pump eliminates device related complications due to negative pressure generated at the inlet, and guarantees stable hemodynamics. Its application is simple and safe and minimal operator intervention is needed, making the Affinity pump particularly suited for veno-venous bypass.