Venovenous bypass in liver transplantation: Exploring the benefits, efficacy, and safety.

Venovenous bypass (VVB) is a technique used in liver transplantation (LT) to maintain hemodynamic stability and abdominal organ perfusion and thereby improve patient outcomes. Despite its perceived benefits, VVB utilization has declined globally due to concerns related to heparinization, major bleeding and the need for expertise. Recent advancements, such as percutaneous cannulation techniques and improved extracorporeal technology have improved the safety of VVB in LT. This paper presents a modified VVB circuit with enhanced safety features. Cannulation plays a pivotal role in VVB establishment, with percutaneous methods increasingly favored. Studies demonstrate VVB's efficacy in improving patient outcomes with lower incidence of acute kidney injury and reduced operative time and blood loss, with no added morbidity or mortality. However, its routine use faces challenges, with alternative techniques gaining traction. Our experience highlights VVB's role in various clinical scenarios, including patients with high Model for End-Stage Liver Disease (MELD) scores, challenging surgical anatomy, portal vein thrombosis and pre-existing cardiovascular disease, emphasizing its safety and efficacy. Continued research is needed to optimize VVB techniques and ensure better outcomes for liver transplant recipients.

The effects of venovenous bypass use in liver transplantation with piggyback technique: a propensity score-weighted analysis.

Venovenous bypass (VVB) use during liver transplantation (LT) is notably variable among the centres and it is actually restricted to surgically complex cases, severely unstable recipients or grafts from high-risk donors. Historically, VVB was associated with the classical LT with caval cross clamping, while not much is known about the safety of this technique applied to piggyback LT. This retrospective observational study evaluated the effects of VVB applied to piggyback LT on mortality, hospital outcomes, postoperative graft and other organ dysfunction. We retrospectively collected data about recipient status, surgical complexity and graft quality of all the piggyback LTs performed at the Transplant Unit of IRCCS Azienda Ospedaliero-Universitaria di Bologna, Italy, from January 2012 to December 2022. A propensity score (PS) was built taking into account the variables possibly associated with either VVB choice and the investigated outcomes with the average treatment overlap method. PS-weighted general linear models (GLMs) were developed to investigate the adjusted effect of VVB use on the selected outcomes. The final analysis included 874 LT cases, of whom 74 (8.5%) underwent VVB. The effective sample sizes after PS-weighting were 280.2 and 64.3 patients in the no-VVB and VVB groups, respectively. PS-weighted GLMs did not show any differences regarding hospital and graft-related outcomes. However, significantly higher odds ratios for serum creatinine > 2 mg/dL and AKIN stage 2 or 3 during the first 24 h after ICU admission together with a higher renal replacement therapy need during ICU stay were reported for VVB exposure in the weighted analyses. This study suggests similar mortality and length of stay but a higher risk for postoperative acute kidney injury in patients undergoing piggyback LT with VVB.

The Use of Extracorporeal Circulation to Facilitate the Resection of a Large Retroperitoneal Sarcoma With Major Vessel Involvement: A Single-Center Review of 20 Cases.

OBJECTIVE: To describe the introduction of extracorporeal corporeal oxygenation (ECMO) to facilitate the surgical resection of large retroperitoneal sarcomas involving major vessels and to report preliminary outcomes. DESIGN: A case series. SETTING: At a tertiary university hospital and state sarcoma center. PARTICIPANTS: Patients undergoing retroperitoneal sarcoma resection requiring inferior vena cava (IVC) reconstruction between June 2018 and March 2022. INTERVENTION: ECMO for retroperitoneal tumor resection requiring IVC reconstruction. MEASUREMENTS AND MAIN RESULTS: A total of 20 patients underwent ECMO-assisted retroperitoneal sarcoma resection and IVC reconstruction. The median age was 60.5 years (IQR 48-69); 15 women and 5 men. The median procedure and ECMO durations were 10.8 hours (IQR 8.5-12.4 hours) and 2.2 hours (IQR 62-218 minutes), respectively. The median intensive care unit and hospital lengths of stay were 4 days (IQR 3-5 days) and 21 days (IQR 14-31 days), respectively. All 20 patients received packed cell transfusions (median 8 per patient [IQR 4-14]); 11 patients required fresh frozen plasma, 6 required platelets, and 11 required fibrinogen supplementation. One patient required recombinant activated factor VII. Sixteen patients experienced acute kidney injury, with 12 patients progressing to chronic kidney disease. Three patients were required to return to the operating room within 7 days, with no returns within the first 24 hours. There was no in-hospital or 30-day mortality. Survival at 3 years was 84%. CONCLUSIONS: ECMO for resecting large retroperitoneal tumor resection was introduced successfully and facilitated satisfactory outcomes for many patients who might otherwise have been considered too high risk.

Anesthesia management of combined sequential heart-liver transplantation using a caval clamp without venovenous bypass: A case report.

Familial amyloid polyneuropathy, an autosomal-dominant disease due to mutations in the transthyretin gene, often affects the heart and liver, and is treated best with a combined heart-liver transplantation (CHLT). Although it remains an uncommonly performed procedure, the number of patients undergoing CHLT is increasing. Because of the complexity associated with dual pathophysiology, CHLT poses an extraordinary challenge for anesthesia management. Either both heart and liver transplantation are performed on cardiopulmonary bypass (CPB); or heart transplantation is performed on CPB, followed by liver transplantation with venovenous bypass. Recent reports suggested that liver transplantation can be performed without bypass using the inferior vena cava-sparing technique. However, both bypass and caval sparing technique have their own complications. Here, we present the anesthesia management in a case of sequential heart-liver transplantation using a routine caval cross-clamp technique without venovenous bypass. A 48-year-old man complaining of chest tightness, chest pain, and shortness of breath was diagnosed with amyloid cardiomyopathy. Cardiac ultrasonography revealed thickening of ventricular walls and left ventricular systolic insufficiency (ejection fraction decreased from 46% to ∼20% in 6 months), which was refractory to medical therapy. Symptoms occurred repeatedly. Therefore, CHLT was planned. Heart transplantation was performed smoothly under general anesthesia and standard CPB. His heart functioned well with dobutamine and epinephrine infusion. Subsequently, the patient was weaned from CPB. Liver transplantation was planned using the piggyback procedure with the caval sparing technique. However, upon caval clamping, unexpected blood loss occurred. Clamping of the caval was tested followed by cross-clamping. Norepinephrine, epinephrine, and dobutamine were administered. After the hepatic vein was anastomosed, the clamp was released and nitroglycerin was administered. Hemodynamics was stable, and the patient was discharged after 37 days of hospitalization. The case indicates that CHLT could be performed using caval clamp without venovenous bypass in selected patients.

Which cava anastomotic techniques are optimal regarding immediate and short-term outcomes after liver transplantation: A systematic review of the literature and expert panel recommendations.

BACKGROUND: It has long been debated whether cava anastomosis should be performed with the piggyback technique or cava replacement, with or without veno-venous bypass (VVB), with or without temporary portocaval shunt (PCS) in the setting of liver transplantation. OBJECTIVES: To identify whether different cava anastomotic techniques and other maneuvers benefit the recipient regarding short-term outcomes and to provide international expert panel recommendations. DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: A systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel (CRD42021240979). RESULTS: Of 3205 records screened, 307 publications underwent full-text assessment for eligibility and 47 were included in qualitative synthesis. Four studies were randomized control trials. Eighteen studies were comparative. The remaining 25 were single-center retrospective noncomparative studies. CONCLUSION: Based on existing data and expert opinion, the panel cannot recommend one cava reconstruction technique over another, rather the surgical approach should be based on surgeon preference and center dependent, with special consideration toward patient circumstances (Quality of evidence: Low | Grade of Recommendation: Strong). The panel recommends against routine use of vevo-venous bypass (Quality of evidence: Very Low | Grade of Recommendation: Strong) and against the routine use of temporary porto-caval shunt (Quality of evidence: Very Low | Grade of Recommendation: Strong).

The technical aspects of ex vivo hepatectomy with autotransplantation: a systematic review and meta-analysis.

PURPOSE: Ex vivo hepatectomy is the incorporation of liver transplant techniques in the non-transplant setting, providing opportunity for locally advanced tumors found conventionally unresectable. Because the procedure is rare and reports in the literature are limited, we sought to perform a systematic review and meta-analysis investigating technical variations of ex vivo hepatectomies. METHODS: In the literature, there is a split in those performing the procedure between venovenous bypass (VVB) and temporary portacaval shunts (PCS). Of the 253 articles identified on the topic of ex vivo resection, 37 had sufficient data to be included in our review. RESULTS: The majority of these procedures were performed for hepatic alveolar echinococcosis (69%) followed by primary and secondary hepatic malignancies. In 18 series, VVB was used, and in 18, a temporary PCS was performed. Comparing these two groups, intraoperative variables and morbidity were not statistically different, with a cumulative trend in favor of PCS. Ninety-day mortality was significantly lower in the PCS group compared to the VVB group (p=0.03). CONCLUSION: In order to better elucidate these differences between technical approaches, a registry and consensus statement are needed.

Peripheral Cardiopulmonary Bypass in Two Patients With Symptomatic Tracheal Masses: Perioperative Challenges.

Tracheal tumors or masses causing critical airway obstruction require resection for symptom relief. However, the location and extent of these tumors or masses often preclude conventional general anesthesia and tracheal intubation. Peripheral cardiopulmonary bypass often is required before anesthetizing these patients. Herein, two cases of patients with tracheal masses, in whom awake peripheral cardiopulmonary bypass was instituted, are reported. The first case was that of an obese male child weighing 102 kg, with tracheal rhinoscleroma, who developed Harlequin, or north-south, syndrome after institution of femorofemoral venoarterial partial cardiopulmonary bypass. The second case was that of a female patient with adenoid cystic carcinoma of the trachea causing near-total central airway occlusion. She had severe pulmonary artery hypertension, which prevented the use of venovenous bypass. Instead, femoral vein-axillary artery venoarterial bypass was established to avoid Harlequin syndrome. Some of the challenges encountered were the development of Harlequin syndrome with risk of myocardial and cerebral ischemia, type and conduct of extracorporeal bypass, choice of monitoring sites, and provision of regional anesthesia for peripheral extracorporeal cannulations. Management of such patients needs frequent troubleshooting and multidisciplinary coordination for a successful surgical outcome.

Successful resuscitation after hyperkalemic cardiac arrest during liver transplantation by converting veno-venous bypass to veno-arterial ECMO.

INTRODUCTION: Intraoperative cardiac arrest (ICA) is a feared complication during liver transplantation (LTx), typically occurring during reperfusion. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used for post-reperfusion cardiac arrest. CASE REPORT: We present a case of successful resuscitation after hyperkalemic ICA during the pre-anhepatic phase of a second liver transplantation by converting veno-venous bypass (VVB) to VA-ECMO. DISCUSSION: While this technique has been recommended for ICA during reperfusion, it has never been reported during the pre-anhepatic phase. VA-ECMO can be a lifesaving extension to cardiopulmonary resuscitation for ICA during LTx with beneficial neurological outcome by providing perfusion while the cause of ICA is reversed. CONCLUSION: Conversion of VVB to VA-ECMO should be considered in all patients who suffer from ICA during LTx with use of VVB. With VVB installed, conversion to VA-ECMO is fast and effective. If VVB is not used, early VA-ECMO should be considered for ICA.

Venovenous bypass using continuous renal replacement therapy and endovascular inferior vena cava reconstruction to treat bilateral massive iliocaval deep venous thrombosis.

Many inferior vena cava (IVC) anomalies remain asymptomatic because of collateral circulation, but thrombosis of these channels can cause acute deep venous thrombosis with serious sequelae. For those with threatened limbs, anticoagulation is the mainstay of treatment, with endovascular pharmacomechanical thrombolysis replacing open surgical thrombectomy. Described is a severe case of massive iliocaval deep venous thrombosis with bilateral lower extremity Rutherford IIb acute limb ischemia in a patient with congenital IVC atresia. After initial thrombolysis, endovascular IVC reconstruction was accomplished to decompress the lower extremities. The patient ultimately required a right through-knee amputation but remains ambulatory with a prosthetic.

Ex vivo liver resection coupled with associated liver partition and portal vein ligation: Combining existing techniques to achieve surgical resectability.

Incorporation of liver transplant techniques in hepatopancreaticobiliary surgery has created an opportunity for the resection of locally advanced hepatic tumors formerly considered unresectable. A 73-year-old woman presented with cholangiocarcinoma involving inferior vena cava, all three hepatic veins, and right anterior portal pedicle, initially deemed nonoperative. This case demonstrates the first combined application of associating liver partition and portal vein ligation for staged hepatectomy and ex vivo resection to perform an R0. For diseases dependent upon resection, surgical advances and innovations expand the spectrum of interventions through interdisciplinary techniques.

A new classification of inferior vena cava thrombus in renal cell carcinoma could define the need for cardiopulmonary or venovenous bypass.

INTRODUCTION: Although the level of inferior vena cava (IVC) thrombus governs the type of surgical approach, there is no consistency in reporting the levels of IVC thrombus in the literature. This prospective study illustrates a simple three-level classification based on the need for clamping hepatoduodenal ligament and venovenous or cardiopulmonary bypass. MATERIALS AND METHODS: Between January 2010 and June 2014, 30 patients of renal mass with renal vein and/or IVC thrombus were treated after classifying the IVC thrombus into three levels on the basis of need for clamping the hepatoduodenal ligament. After excluding renal vein thrombi, level I was described as thrombus located caudal to the hepatic vein. Level II included all retrohepatic, suprahepatic infradiaphragmatic or supradiaphragmatic thrombi reaching till the right atrium. Atrial thrombi were categorized as level III. Level I and II thrombi were managed without venovenous or cardiopulmonary bypass. Level III thrombus required cardiopulmonary bypass. RESULTS: Of 26 patients with thrombus, 13 had level I thrombus. Of eight cases with level II thrombus, three were retrohepatic, three were suprahepatic infradiaphragmatic and two were supradiaphragmatic. All were removed successfully. Of five patients with level III thrombus, three were operated with cardiopulmonary bypass while the remaining two patients were too sick to be taken up for surgery. The median hepatoduodenal ligament clamp time was 10 min. One patient with level II thrombus had transient liver enzyme elevation. CONCLUSION: Renal vein thrombus should not be categorized as level I thrombus. Level II thrombus, irrespective of its relation to the diaphragm, could be managed without venovenous or cardiopulmonary bypass.

Liver resection using total vascular exclusion of the liver preserving the caval flow, in situ hypothermic portal perfusion and temporary porta-caval shunt: a new technique for central tumors.

Standard total vascular exclusion (TVE) of the liver is indicated for resection of tumors involving or adjacent to the vena cava and/or the confluence of the hepatic veins. The duration of liver ischemia can be prolonged by combined portal hypothermic perfusion of the liver (in or ex situ). The use of a venovenous bypass (VVB) during standard TVE maintains stable hemodynamics as well as optimal renal and splanchnic venous drainage. When the hepatic veins can be controlled, TVE preserving the caval flow negates the need for VVB. However this technique remains limited in duration as it is performed under warm ischemia (so-called normothermia) of the liver. To prolong the ischemia time, we have designed a modification of TVE with preservation of the caval flow including the use of temporary porta-caval shunt (PCS) and hypothermic perfusion of the liver. We describe here the first two cases of this new technique. Two patients underwent left hepatectomy extended to segments 5 and 8 (also called extended left hepatectomy) for large centrally located tumors. TVE lasted seventy-two and seventy-nine minutes, respectively. The postoperative course was uneventful and both patients were discharged on day ten and day twenty-five respectively. Both are alive without recurrence at ten and seven months following surgery. Provided the roots of the hepatic veins can be controlled, this technique combines the advantages of standard TVE with in situ hypothermic perfusion and VVB and obviates the need and the subsequent risks of the latter.

A comparative study of the classic and piggyback techniques for orthotopic liver transplantation.

BACKGROUND: The classic technique of hepatectomy with venovenous bypass may cause a longer anhepatic phase and increase the rate of some complications, such as post-operative renal failure and thromboembolic events. But, in some cases, such as tumors and anatomic difficulties, the surgeon is obligated to use the classic technique even though there is some controversy about the safety of this technique without venovenous bypass in liver transplantation. The aim of this study was to compare the results of using the classic technique without venovenous bypass and the piggyback technique for liver transplantation. METHODS: A retrospective case-series study was conducted on 227 consecutive successful liver transplants, including 55 cases in which the classic technique was used and 172 cases in which the piggyback technique was used. The transplants were performed from March 2010 through June 2011 in the Visceral Transplantation Ward at Namazi Hospital in Shiraz, Iran. The piggyback method was the preferred approach for hepatectomy, but the classic technique without venovenous bypass was performed in cirrhotic cases with anatomic difficulties, when there was a tumor, or when the surgeon preferred it. RESULTS: There were no significant differences in post-operative rise in creatinine, decreases in intraoperative blood pressure, transfused packed red blood cells (RBC), or survival rates between the groups. Warm ischemic time (duration that donor liver is out of ice until it's blood reperfusion in the recipient) was approximately seven minutes longer in the classic group (P = 0), but it was less than 52 minutes, which is an acceptable time for this phase. Hospital stays were shorter in the classic group than in the piggyback group (P = 0.024). CONCLUSION: Although the piggyback technique is the preferred technique for hepatectomy in liver transplantation, the classic technique without venovenous bypass can be used safely in cirrhotic livers when necessary or if the physician prefers it.

Establishment of orthotopic liver transplantation model in pigs without veno-venous bypass / 中华器官移植杂志

Objective To summarize the experience of orthotopic liver transplantation in pigs without veno-venous bypass.Method In general,Bama miniature pigs were used as both the donors and the recipients.Suprahepatic inferior vena cava and portal vein anastomosis was performed with running prolene sutures.After completion of the portal vein anastomosis,the graft was reperfused.Infrahepatic inferior vena cava anastomosis and hepatic artery anastomosis were performed in a similar fashion.Finally,the common bile duct was reconstructed.Result For all of the transplant procedures,the average cold ischemic time was 356.3 ± 66.4 min and anhepatic time 22.5 ± 2.6 min,and the average operative time was 185.7 ± 24.8 min.During the anhepatic phase,the central venous pressure (CVP) and the mean arterial pressure (MAP) were significantly lower than those at baseline (P＜ 0.05).Heart rate (HR),on the other hand,was increased significantly during the anhepatic phase (P＜0.05).By the time the portal vein and the hepatic artery were reperfused,and CVP and MAP were gradually elevated,and HR gradually reduced.All receptors were successfully extubated and awake after surgeries.On the third postoperative day they began to eat.All receptors survived during the intraoperative period,and the survival rate was 93.8％ (15/16) on the fifth postoperative day.One receptor was died on the third postoperative day due to abdominal infection.Conclusion This model has satisfactory stability and reproducibility.Without using any vasoactive substances,to maintain the MAP beyond 50 mmHg in the anhepatic phase and the short anhepatic time are important to perform successful liver transplantation.

Transplante de fígado clínico sem desvio venovenoso / Clinical liver transplantation without venovenous bypass

INTRODUÇÃO: O problema da utilização do desvio venovenoso no transplante de fígado é um ponto de discussão e controvérsia entre anestesistas e cirurgiões transplantadores. Apesar de proporcionar ambiente hemometabólico estável durante a fase anepática o seu uso poderá levar a algumas complicações, inclusive fatais. OBJETIVO: Revisar a prática atual do uso do desvio venovenoso no transplante de fígado clínico, com suas vantagens e desvantagens. MÉTODO: Foi realizada ampla pesquisa na literatura, com especial atenção aos artigos publicados nos últimos 10 anos e indexados ao PubMed e Medline. Foram utilizados os seguintes descritores de forma cruzada: liver transplantation, venovenous bypass, conventional technique, classic technique. Entre os artigos encontrados foram considerados para análise os mais relevantes além dos considerados "clássicos" sobre o assunto. CONCLUSÃO: Transplante de fígado sem desvio venovenoso é técnica segura e rápida. Pode ser utilizada, com poucas exceções, sem acarretar complicações maiores nos pacientes com doença hepática.

INTRODUCTION: The use of a venovenous bypass in liver transplantation is a controversy source and discussion among anesthetists and transplant surgeons. Although it provides a stable hemodynamic state and metabolism during the anhepatic stage, venovenous bypass may lead to a number of complications, some of them with death. AIM: To review the current practice of using clinic venovenous bypass in liver transplantation, with its advantages and disadvantages. METHOD: A broad review of the literature was carried out, paying especial attention to articles published in the past ten years and indexed in PubMed and Medline. The following cross-referenced headings were used: liver transplantation, venovenous bypass, conventional technique, classic technique. The articles chosen for analysis were those of the greatest relevance and those considered "classics" in the subject. CONCLUSION: Liver transplantation without venovenous bypass is a safe and rapid technique. In most cases it can be used without giving rise to serious complications in patients with liver disease.

The need for venovenous bypass in liver transplantation.

Since introduction of the conventional liver transplantation (CLTx) by Starzl, which was based on the resection of recipient inferior vena cava (IVC) along the liver, the procedure has undergone several refinements. Successful use of venovenous bypass (VVB) was first introduced by Shaw et al., although in recent decades there has been controversy regarding the routine use of VVB during CLTx. With development of piggyback liver transplantation (PLTx), the use of caval clamping and VVB is avoided, leading to fewer complications related to VVB. However, some authors still advocate VVB in PLTx. The great diversity among centers in their use of VVB during CLTx, or even along the PLTx technique, has led to confusion regarding the indication setting for VVB. For this reason, we present an overview of the use of VVB in CLTx, the target of patients for whom VVB could be beneficial, and the needs assessment of VVB for patients undergoing PLTx. Recent studies have shown that with the advancement of surgical skills, refinement of surgical techniques, and improvements in anesthesiology, there are only limited indications for doing CLTx with VVB routinely. PLTx with preservation of IVC can be performed in almost all primary transplants and in the majority of re-transplantations without the need for VVB. Nevertheless, in a few selective cases with severe intra-operative hemodynamic instability, or with a failed test of transient IVC occlusion, the application of VVB is still justifiable. These indications should be judged intra-operatively and the decision is based on each center's preference.