Small for size syndrome following living donor and split liver transplantation

The field of liver transplantation is limited by the availability of donor organs. The use of living donor and split cadaveric grafts is one potential method of expanding the donor pool. However, primary graft dysfunction can result from the use of partial livers despite the absence of other causes such as vascular obstruction or sepsis. This increasingly recognised phenomenon is termed "Small-for-size syndrome" (SFSS). Studies in animal models and humans have suggested portal hyperperfusion of the graft combined with poor venous outflow and reduced arterial flow might cause sinusoidal congestion and endothelial dysfunction. Graft related factors such as graft to recipient body weight ratio < 0.8, impaired venous outflow, steatosis > 30% and prolonged warm/cold ischemia time are positively predictive of SFSS. Donor related factors include deranged liver function tests and prolonged intensive care unit stay greater than five days. Child-Pugh grade C recipients are at relatively greater risk of developing SFSS. Surgical approaches to prevent SFSS fall into two categories: those targeting portal hyperperfusion by reducing inflow to the graft, including splenic artery modulation and portacaval shunts; and those aiming to relieve parenchymal congestion. This review aims to examine the controversial diagnosis of SFSS, including current strategies to predict and prevent its occurrence. We will also consider whether such interventions could jeopardize the graft by compromising regeneration.     

Utility of Polyethylene Terephthalate (Dacron) Vascular Grafts for Venous Outflow Reconstruction in Living-Donor Liver Transplantations

BackgroundVenous outflow reconstruction of modified right-lobe liver grafts has been shown to prevent the occurrence of graft congestion and subsequent complications, including graft loss. In the present study, we aimed to investigate the safety and efficacy of Dacron grafts for venous reconstruction in living donor liver transplantation (LDLT).MethodsBetween January 2016 and January 2018, Dacron grafts were used in 148 liver transplants. Of these, 104 patients who had a follow-up computerized tomography (CT) scan were enrolled into the study. A total of 179 outflow hepatic veins including V5, V8, partial middle hepatic vein, and accessory inferior right hepatic veins (IRHV) were reconstructed using synthetic Dacron grafts. Graft patency was evaluated with both intraoperative Doppler ultrasonography following reconstruction, and a follow-up CT was performed on the postoperative day 7 (±1). Retrospective data collection included demographics, parameters for small-for-size (laboratory tests [bilirubin, International Normalized Ratio] and ascites) syndrome, postoperative morbidity, and mortality.ResultsFollow-up CT revealed graft patency in 155 out of 179 (86.6%) vascular grafts. Postoperative seventh-day patency rates for each reconstructed vein were as follows: V5, 87.5% (70/80); V8, 87.7% (50/57); partial middle hepatic vein, 100% (11/11); and IRHV, 77.4% (24/31). No major graft-related complications (early graft dysfunction, graft infection) or graft-related mortality were observed. None of the recipients developed small-for-size syndrome based on laboratory tests and clinical findings.ConclusionsDacron vascular grafts appear as an advantageous and useful alternative for venous outflow reconstruction in LDLT.     

Reconstruction of the middle hepatic vein tributaries draining segments V and VIII of a right liver graft by using the recipient’s own middle hepatic vein and vascular closure staples

A right liver graft lacking the middle hepatic vein can result in congestion of the anterior segment. We describe a method of reconstructing the middle hepatic vein tributaries by using the recipient’s own middle hepatic vein with vascular closure staples. During a living donor right liver transplantation, the middle hepatic vein tributaries draining segments V (V5) and VIII (V8) of the right lobe graft were reconstructed using the recipient’s own middle hepatic vein and secured with vascular closure staples. Computed tomography showed good venous outflow from the middle hepatic vein and no congestion or atrophy of the anterior segment of the right liver grafts. Thus, using the recipient’s own middle hepatic vein is a suitable option for reconstructing the middle hepatic vein tributaries (V8 and V5) in right-liver living donor transplantation and the application of vascular closure staples helps to accomplish this.     

改进成人间活体供肝移植的手术技术

目的研究并改进成人间活体供肝移植的手术技术。方法自2002年1月至2005年8月,施行了16例成人间活体右半供肝移植。手术中改进了技术,包括右肝静脉重建、肝中静脉分支搭桥、肝动脉搭桥及胆道吻合等。结果所有供者均无严重并发症及死亡。移植肝与受者重量比（GRWR）为0．72％～1．24％,其中9例〈1．0％,2例〈0．8％。手术除了采用移植肝的右肝静脉与受者下腔静脉（IVC）直接吻合外,5例加行右肝下静脉重建、5例取自体大隐静脉行肝中静脉分支与IVC间搭桥,保证了右肝流出道通畅。最早手术的2例受者中,1例发生肝静脉吻合口狭窄,另1例发生小肝综合征,最终导致死亡。后阶段手术的14例受者均未发生小肝综合征;发生并发症5例,分别为急性排斥反应、肝动脉栓塞、胆漏、左膈下脓肿及肺部感染;1例再次肝移植后因肺部感染,多器官功能衰竭（MOF）死亡。结论活体供肝移植中采用改进的手术技术,特别是肝静脉流出道重建的方法,可有效避免发生小肝综合征。     

采用不含肝中静脉的右半肝行成人间活体肝移植

目的探讨采用不含肝中静脉的右半肝行成人间活体肝移植的可行性及安全性。方法2002年1月至2005年8月,我院施行了16例成人间右半肝活体肝移植,术中采用了不含肝中静脉的右半肝移植物,同时进行了一系列改良的手术技术包括肝右静脉的重建,右肝下静脉的重建,肝中静脉分支的搭桥等改进。结果全组供者无严重并发症及死亡。前2例受者中,1例发生肝静脉吻合口狭窄,1例因发生小肝综合征,死于肝功进行性恶化。后14例受者中发生并发症5例:急性排斥反应,肝动脉栓塞,胆漏,左膈下脓肿及肺部感染各1例;1例再移植术后肺部感染死于MODS。14例中除肝右静脉与下腔静脉(IVC)直接吻合外,其中5例加行右肝下静脉重建,另5例采用自体大隐静脉搭桥行肝中静脉分支与IVC重建,保证了右肝的流出道通畅。移植物与受者重量比(GRWR)为0.72%~1.15%,11例<1.0%,其中2例<0.8%,无小肝综合征发生。结论采用了改进的手术技术,特别是肝静脉流出道的充分重建可有效的避免小肝综合征,从而使采用不含肝中静脉的活体右半肝移植成为安全可靠的手术方式。     

Life-Threatening Portal Flow Steal Reappearing Under Increased Intrahepatic Vascular Resistance After Living Donor Liver Transplantation

Maintenance of adequate portal inflow is crucial for graft regeneration in adult living donor liver transplantation (ALDLT) to allow the recipients to meet their early metabolic demands. A persistent large spontaneous portosystemic shunt can divert portal flow away from the liver graft, leading to impaired or delayed graft regeneration and subsequent graft failure. The importance of obliterating huge portosystemic shunt during liver transplantation is obvious for successful ALDLT. However, in partial liver graft with a relatively small graft-to-recipient weight ratio (GRWR) (compared with deceased donor whole graft liver transplantation), even the persisting small portosystemic shunt may result in repeated portal flow steal when a liver graft faces increased intrahepatic vascular resistance caused by rejection or graft congestion with hepatic venous outflow stenosis. We present 2 complicated cases of reappearing portal flow steal that were derived from the remaining small portosystemic shunt under the increased vascular resistance of the liver graft, even after interruption of a large portosystemic shunt during ALDLT. Because ALDLT is always a partial liver graft, even when GRWR is over 1%, it is much more vulnerable to hemodynamic changes in portal flow by rejection or graft congestion by hepatic venous outflow obstruction. Therefore, a comprehensive understanding of complex portosystemic shunt and complete reinterruption of reappearing portosystemic shunt, even though small and insignificant, during ALDLT is important for graft salvage procedures before irreversible liver graft damage.     

Adult-to-adult living donor liver transplantation using left lobes: the importance of surgical modulations on portal graft inflow

BACKGROUND: Due to the shortage of available cadaveric organs, living donor liver transplantation (LDLT) has been recently applied extensively in adults. The use of the left lobe should be encouraged because of donor safety, but frequently the metabolic requirements of severely cirrhotic patients are great and subsequent graft dysfunction is encountered after transplantation. The importance of increased portal inflow to the graft in previously severely cirrhotic patients and other hemodynamic changes in LDLT using left lobes are still under debate, as are the surgical modulations to correct them. In this study, we have reported an initial series of adult-to-adult LDLT using left lobes, underlining the hemodynamic changes encountered during the transplant and the surgical modulations we applied to correct them. METHODS: Eight adult recipients underwent left lobe liver transplantation from living donors. Portal vein pressure and central venous pressure were measured before and after surgical modulation. RESULTS: We encountered four cases of small-for-size syndrome. Two patients were retransplanted; the other two died. Seventy-five percent of our recipients survived and 50% did not require further surgery. CONCLUSION: Surgical portal inflow modulation should be considered in cases of left lobe liver transplantation between adults.     

Split-Cava Technique: Liver Splitting for Two Adult Recipients

Split-liver transplantation for 2 adult recipients is a challenging procedure because of the need to split through the midplane of the donor liver. In applied techniques, usually the middle hepatic vein is retained with the left split and the vena cava retained with the right split graft, particularly to avoid serious venous congestion of the right graft after reperfusion. The indispensable division of the caudate lobe veins lead to uncertain viability of liver segment I, and resection might be necessary. To provide optimal venous drainage of both hemiliver grafts, we developed the split-cava technique. This article describes our new technique of liver splitting, which has been successfully used in 2 in situ harvesting procedures. (Liver Transpl 2000;6:703-706.)     

Indications for and techniques of hepatic vein reconstruction in hepatectomy for hepatocellular carcinoma]

The indications for hepatic vein reconstruction (HVR) in resection of segments 7 and 8 for hepatocellular carcinoma (HCC) have been controversial. Although right hepatic vein ligation may not cause complications in some patients, hepatic parenchymal congestion and liver dysfunction occur in others. We performed HVR using autovein grafts in 6 HCC patients, patch grafts in 3, and direct anastomosis in 1, respectively. From this experience, we consider that HVR may be indicated in patients with a discolored hepatic area after hepatic vein ligation, and without inferior right hepatic vein and intrahepatic venous communication. Furthermore, although repeat hepatectomy has resulted in improved survival in patients with recurrent hepatic tumors, when the right hepatic vein has already been ligated, numerous intrahepatic communicating vein anastomoses develop. In repeat hepatectomy in such patients, uncontrollable massive bleeding from hepatic veins occurs. Therefore, HVR is recommended to maintain the previous hepatic vein anatomy. Recently, the indications for HVR have been studied to prevent hepatic vein congestion and liver dysfunction in both the remant and graft livers in living-related donor partial liver transplantation from the standpoint of hemodynamics. Additionally, the technique of direct hepatic vein anastomosis is presented.     

成人间活体肝移植的手术技术改进(附13例报告)

目的探讨成人间活体肝移植的手术技术改进.方法2005年3-6月,施行了13例成人间右半肝活体肝移植,其中1例接受了2个左半肝,另1例接受了1个活体右半肝,1个尸体左半肝,术中采用了改良的手术技术,包括右肝静脉的重建,肝中静脉分支的搭桥,肝动脉搭桥及胆道吻合的改进.结果全组供体无严重并发症及死亡,受体发生并发症4例,包括肝动脉栓塞,胆漏,右膈下脓肿及肺部感染各1例,1例再移植因术后肺部感染,导致多器官衰竭（MOF）死亡.13例中除右肝静脉与下腔静脉（IVC）直接吻合,5例加行右肝下静脉重建,另5例采用自体大隐静脉搭桥行肝中静脉分支与IVC重建,保证了右肝的流出道通畅.移植物与受体重量比（GRWR）为0.72%至1.24%,其中9例＜1.0%,2例＜0.8%,无小肝综合征发生.结论采用了改进的手术技术,特别是肝静脉流出道的充分重建可有效避免小肝综合征,从而使活体右半肝移植成为相当安全的手术.     

Donor graft outflow venoplasty in living donor liver transplantation.

Hepatic venous outflow reconstruction is a key to successful living donor liver transplantation (LDLT) because its obstruction leads to graft dysfunction and eventual loss. Inclusion or reconstruction of most draining veins is ideal to ensure graft venous drainage and avoids acute congestion in the donor graft. We developed donor graft hepatic venoplasty techniques for multiple hepatic veins that can be used in either right- or left-lobe liver transplantation. In left-lobe grafts, venoplasty consisting of the left hepatic vein and adjacent veins such as the left superior vein, middle hepatic vein, or segment 3 vein is performed to create a single, wide orifice without compromising outflow for anastomosis with the recipient's vena cava. In right lobe graft where a right hepatic vein (RHV) is adjacent with a significantly-sized segment 8 vein, accessory RHV, and/or inferior RHV, venoplasty of the RHV with the accessory RHV, inferior RHV, and/or segment 8 vein is performed to create a single orifice for single outflow reconstruction with the recipient's RHV or vena cava. Of 35 venoplasties, 2 developed hepatic venous stenoses which were promptly managed with percutaneous interventional radiologic procedures. No graft was lost due to hepatic venous stenosis. In conclusion, these techniques avoid interposition grafts, are easily performed at the back table, simplify graft-to-recipient cava anastomosis, and avoid venous outflow narrowing.     

Review of the surgical approach to prevent small-for-size syndrome in recipients after left lobe adult LDLT

Left lobe liver grafts increase the donor safety in adult-to-adult living-donor liver transplantation (ALDLT). However, the left lobe graft provides about 30–50 % of the required liver volume to adult recipients, which is insufficient to sustain their metabolic demands, which can lead to small-for-size syndrome (SFSS). Transient portal hypertension and microcirculatory hemodynamic derangement, apart from outflow obstruction, during the first week after reperfusion are the critical events associated with small-for-size graft transplantation. The incidence of SFSS in left lobe ALDLT can be decreased by increasing the left lobe graft volume by effective utilization of the caudate lobe with preserved vascular supply, by modulating the portal pressure with splenectomy or a porto-systemic shunt or by hepatic venous outflow reconstruction to prevent the development of venous congestion. In this review, we discuss the pathophysiology of SFSS and the various surgical strategies that can be performed to prevent SFSS in an effort to enhance the donor safety during living-donor liver transplantation.     

Hepatic venous stenosis in partial liver graft transplantation detected by color Doppler ultrasound before and after radiological interventional management

Hepatic outflow insufficiency remains one of the major complications causing postoperative graft failure especially among partial liver graft transplantations (PLT) including living donor liver transplantation (LDLT), reduced size liver transplantation (RLT), and split liver transplantation (SLT). These procedures are different from the whole liver graft transplantations (OLT), which include multiple vascular anastomoses. Color Doppler ultrasound (CDUS) was used to evaluate the hepatic venous outflow from grafts before and after radiological interventional management and to document treatment effects. From June 1994 to March 2003, our 136 cases of PLTs included 131 LDLTs, two RLTs, and three SLTs. Seven cases (six children and one adult) showed postoperative hepatic vein outflow obstruction and persistent massive ascites, as detected by color Doppler ultrasound (CDUS) and confirmed by interventional angiography. The CDUS showed a monophasic flat waveform with a relatively low hepatic vein average peak velocity (Va) in all cases (mean 11 cm/s). Successful interventional procedures included balloon dilatation in three cases and metallic stent replacement in four cases. CDUS was used with guidance during the procedure to confirm restoration of normal hepatic vein flow with a multiphasic waveform and an objective increase of average flow velocity (high to average 66 cm/s). Ascites disappeared dramatically after the procedure. In conclusion CDUS is the prime modality to diagnose and document a treatment response.     

Technical solutions for venous outflow reconstruction in damaged liver grafts during procurement: case reports

The incidence and clinical consequences of hepatic injuries (parenchymal, vascular, and biliary) due to surgical handling during multiorgan procurement are still underestimated. Surgical damage to liver grafts may lead to an increased mortality and graft dysfunction rate; therefore, multiorgan procurements require a high level of expertise and training. We report our experience in two cases of accidental venous outflow damage during liver procurement focusing on our repair strategies. In one case, a short suprahepatic inferior vena cava (IVC) was extended by a venous cuff obtained from a long infrahepatic IVC from the same liver graft. In the second case, we observed a complete transection of the middle hepatic vein during in situ splitting procedure. The damage was reconstructed by cadaveric iliac vein interposition. In both cases, liver transplantation was successfully performed without venous complication. An adequate surgical technique in liver procurement and venous reconstruction during living donor and domino liver transplantation are formidable tools to achieve successful liver transplantation with a damaged graft.     

活体肝移植肝静脉流出道狭窄的诊断与治疗

肝静脉流出道狭窄是肝移植术后较为罕见的并发症,在活体肝移植中发生率为2％～4％。2006年6月至2010年5月,解放军总医院2例接受右肝活体肝移植的患者术后出现肝静脉流出道狭窄,接受保守治疗或介入球囊扩张成形术治疗。术后疗效显示：保守治疗肝静脉流出道狭窄具有一定的风险性;而介入肝静脉造影、球囊扩张以及金属支架置入能有效诊断和治疗肝静脉流出道狭窄。     

Split liver transplantation

OBJECTIVE: This study reviews the indications, technical aspects, and experience with ex vivo and in situ split liver transplantation. BACKGROUND: The shortage of cadaveric donor livers is the most significant factor inhibiting further application of liver transplantation for patients with end-stage liver disease. Pediatric recipients, although they represent only 15% to 20% of the liver transplant registrants, suffer the greatest from the scarcity of size-matched cadaveric organs. Split liver transplantation provides an ideal means to expand the donor pool for both children and adults. METHODS: This review describes the evolution of split liver transplantation from reduced liver transplantation and living-related liver transplantation. The two types of split liver transplantation, ex vivo and in situ, are compared and contrasted, including the technique, selection of patients for each procedure, and the most current results. RESULTS: Ex vivo splitting of the liver is performed on the bench after removal from the cadaver. It is usually divided into two grafts: segments 2 and 3 for children, and segments 4 to 8 for adults. Since 1990, 349 ex vivo grafts have been reported. Until recently, graft and patient survival rates have been lower and postoperative complication rates higher in ex vivo split grafts than in whole organ cadaveric transplantation. Further, the use of ex vivo split grafts has been relegated to the elective adult patient because of the high incidence of graft dysfunction (right graft) when placed in an emergent patient. Reasons for the poor function of ex vivo splits except in elective patients have focused on graft damage due to prolonged cold ischemia times and rewarming during the long benching procedure. In situ liver splitting is accomplished in a manner identical to the living donor procurement. This technique for liver splitting results in the same graft types as in the ex vivo technique. However, graft and patient survival rates reported for in situ split livers have exceeded 85% and 90%, respectively, with a lower incidence of postoperative complications, including biliary and reoperation for bleeding. These improved results have also been observed in the urgent patient. CONCLUSION: Splitting of the cadaveric liver expands the donor pool of organs and may eliminate the need for living-related donation for children. Recent experience with the ex vivo technique, if applied to elective patients, results in patient and graft survival rates comparable to whole-organ transplantation, although postoperative complication rates are higher. In situ splitting provides two grafts of optimal quality that can be applied to the entire spectrum of transplant recipients: it is the method of choice for expanding the cadaver liver donor pool.     

Interpostion vein graft in living donor liver transplantation

In adult-to-adult living donor liver transplantation (LDLT), right lobe grafts without a middle hepatic vein can cause hepatic congestion and disturbance of venous drainage. To solve this problem, various types of interposition vein graft have been used. OBJECTIVES: We used various types of interposition vein grafts for drainage of the paramedian portion of the right lobe in living donor liver transplantation. METHODS: From June 1996 to June 2003, 37 of 176 patients (128 adults, 48 pediatric) who underwent LDLT received vein grafts for drainage of segments V, VIII, or the inferior portion of the right lobe. RESULTS: In 36 adult cases the reconstruction included the inferior mesenteric vein of the donor (n = 14); cadaveric iliac vein stored at cold (4 degrees C) temperature (n = 5); cryopreserved (-180 degrees C) cadaveric iliac vein (n = 10); cryopreserved cadaveric iliac artery (n = 1 case); donor ovarian vein (n = 1); recipient umbilical vein (n = 3); recipient saphenous vein (n = 1); recipient left portal vein (n = 1); recipient left hepatic vein (n = 1). In a pediatric case with malignant hemangioendothelioma that encased and compressed the inferior vena cava, we used an interposition vein graft to replace the inferior vena cava. CONCLUSION: Various types of interposition vein grafts can be used in living donor liver transplantation. Cryopreserved cadaveric iliac vein and artery are useful to solve these drainage problems.     

劈离式肝移植术后移植肝再生的研究

目的研究劈离式肝移植术后移植肝组织的再生规律。方法通过CT检查计算劈离式肝移植术后4例受体在不同时间点的肝体积变化,并检查患者移植术后肝功能。结果受体1术后4个月、1年时肝体积分别是标准体积的114%、97%,肝体积再生率为-11·0%、-24·3%;受体2术后4个月、1年肝体积分别是标准体积的96%、100%,肝体积再生率为24·4%、30·0%。受体3术后2个月肝体积是标准体积的86%,肝体积再生率为12·0%;受体4术后2个月肝体积是标准体积的90%,肝体积再生率为20·0%。4例受体术后肝功能均恢复正常。结论劈离式肝移植供肝有较强的再生能力,能满足受体的代谢需要。     

Risk factors for graft dysfunction after adult-to-adult living donor liver transplantation

The aim of this study was to investigate the risk factors for graft dysfunction after adult-to-adult living donor liver transplantation (LDLT). Thirty-nine adults with chronic cirrhosis underwent LDLT between 1999 and 2004. Their postoperative courses were uneventful with no vascular or bile duct complications early after LDLT, except one mild hepatic artery stenosis. The preoperative MELD scores were significantly higher in the failed graft group (n=5) than the functioning graft group (n=34; P=.004), while the graft liver weight/standard liver volume ratio was similar between these groups. We concluded that a high preoperative MELD score was associated with postoperative graft failure and that graft size had little impact on graft outcome. Although large grafts would seem intuitively more suitable for sick recipients, we did not show a benefit among this cohort; the MELD score was the best predictor, a finding that is also most consistent with donor safety.     

Outflow tract reconstruction in living donor liver transplantation

BACKGROUND: Hepatic venous reconstruction is critical in living donor liver transplantation because outflow obstruction may lead to graft dysfunction or loss. We describe our experience and analyze outcomes with a technique of creating a single outflow tract using venoplasties of the graft and recipient hepatic veins. PATIENTS AND METHODS: A retrospective study was done on 38 consecutive living donor liver transplants performed from June 1994 to March 2000. The grafts included 36 left-side grafts and 2 right-side grafts. Nine grafts had multiple hepatic veins and required a venoplasty of two or three hepatic veins to create a single outflow orifice. Triple recipient hepatic venoplasty was performed in 32 patients, double venoplasty in 5 and none in 1. RESULTS: There were four cases of outflow obstruction, three occurring in patients with a double recipient venoplasty. Two of the problems were remedied intraoperatively by adjusting the position of the graft although two were structural in nature and required the insertion of expandable metallic vascular stents. All donors and recipients with their original grafts are alive at a mean follow-up period of 27 months. CONCLUSION: A triple recipient venoplasty with a matching venoplasty of multiple graft hepatic veins to create a single wide outflow orifice is recommended in living donor liver transplantation using left side grafts.