Hemodynamic profiles during piggyback liver grafts using arterial or portal revascularization

Postreperfusion Syndrome in Patients Receiving Vasoactive Drugs During Liver Graft Reperfusion

OBJECTIVES

The most widely used definition of postreperfusion syndrome in liver transplant is a 30% decrease in mean arterial pressure during the first 5 minutes after vascular unclamping. With these criteria, increased postoperative morbidity has been reported. Vasoactivedrugs couldpreventthis syndrome.Themain objective of our study was to determine the incidence and complications associated with postreperfusion syndrome inpatientswho receivedvasoactive support.

MATERIALS AND METHODS

We studied 246 patients who received norepinephrine infusions to maintain mean arterial pressure ≥60 mm Hg and who were monitored with a Swan-Ganz catheter. Patients received a bolus of adrenaline after vascular unclamping in cases of insufficient response to norepinephrine.

RESULTS

Among the study patients, 57 (23.17%) developed postreperfusion syndrome. Patients who developed postreperfusion syndrome did not present with morepostoperative complications interms ofrenal dysfunction (P = .69), repeat surgery (P = .15), graft rejection (P = .69), transplant replacement surgery (P = .76), hospital stay (P = .70), or survival (P = .17) compared with patients without postreperfusion syndrome.

CONCLUSIONS

In patients who underwent orthotopic liver transplant, in whom vasoactive drugs were administered, a diagnosis of self-limited postreperfusion syndrome during the first 5 minutes after unclamping may not be associated with postoperative complications. The administration of vasoconstrictors may have a preventive effect on the postoperative complications associated with postreperfusion syndrome or they may mask the real incidence of postreperfusion syndrome. A broader definition of postreperfusion syndrome should be accepted.

Effects of Initial Hepatic Artery Followed by Portal Reperfusion Technique on Deceased Donor Liver Transplant Outcomes

OBJECTIVES

Although initial portal vein reperfusion of a liver allograft is nearly standardized, limited data suggest initial hepatic artery reperfusion may improve hemodynamics and posttransplant outcomes.

MATERIALS AND METHODS

We retrospectively reviewed orthotopic liver transplants performed between January 2013 and February 2018. Parameters of liver recipients with initial hepatic artery reperfusion were compared with those with initial portal vein reperfusion.

RESULTS

Of 204 recipients, 53 (26%) were initially perfused from the hepatic artery and 151 (74%) were initially perfused from the portal vein. Demographics between groups did not differ. There were no significant differences in the incidence of acute rejection between recipients with initial hepatic artery reperfusion versus portal vein reperfusion at 3 months and 1 year (1.9% vs 7.9% and 7.5% vs 10.6%; not significant), hepatic artery thrombosis (1.9% vs 4.0% and 1.9% vs 7.3%; not significant), biliary leakage (7.5% vs 4.0% and 9.4 vs 6.6; not significant), biliary strictures (7.5% vs 5.3% and 11.3% vs 7.9%; not significant), or portal or hepatic venous thrombosis/stenosis (5.7% vs 5.3% and 7.5% vs 7.9%; not significant). Furthermore, recipients with initial hepatic artery reperfusion and portal vein reperfusion were both hospitalized for a median of 8.5 days (interquartile range, 6.5-15.5 vs 7.0-14.0 days, respectively), and both groups were in the intensive care unit for a median of 3 days (interquartile range, 2-7 vs 2-4 days, respectively). Initial hepatic artery reperfusion was associated with significantly less intraoperative packet red blood cell transfusion (median, 11.9 U [interquartile range, 11.1-13.1 U] vs 15.5 U [interquartile range, 12.9-17.9 U]; P < .001). The 2 groups did not differ in terms of patient and graft survival.

CONCLUSIONS

Initial reperfusion of liver allografts with arterial, rather than portal, blood has benefits to hemodynamic stability, did not have deleterious effects on outcomes, and resulted in less intraoperative blood utilization.

Impact of Temporary Portocaval Shunting and Initial Arterial Reperfusion in Orthotopic Liver Transplantation

The use of a temporary portocaval shunt (TPCS) as well as the order of reperfusion (initial arterial reperfusion [IAR] versus initial portal reperfusion) in orthotopic liver transplantation (OLT) is controversial and, therefore, still under debate. The aim of this study was to evaluate outcome for the 4 possible combinations (temporary portocaval shunt with initial arterial reperfusion [A+S+], temporary portocaval shunt with initial portal reperfusion, no temporary portocaval shunt with initial arterial reperfusion, and no temporary portocaval shunt with initial portal reperfusion) in a center-based cohort study, including liver transplantations (LTs) from both donation after brain death and donation after circulatory death (DCD) donors. The primary outcome was the perioperative transfusion of red blood cells (RBCs), and the secondary outcomes were operative time and patient and graft survival. Between January 2005 and May 2017, all first OLTs performed in our institution were included in the 4 groups mentioned. With IAR and TPCS, a significantly lower perioperative transfusion of RBCs was seen (P < 0.001) as well as a higher number of recipients without any transfusion of RBCs (P < 0.001). A multivariate analysis showed laboratory Model for End-Stage Liver Disease (MELD) score (P < 0.001) and IAR (P = 0.01) to be independent determinants of the transfusion of RBCs. When comparing all groups, no statistical difference was seen in operative time or in 1-year patient and graft survival rates despite more LTs with a liver from a DCD donor in the A+S+ group (P = 0.005). In conclusion, next to a lower laboratory MELD score, the use of IAR leads to a significantly lower need for perioperative blood transfusion. There was no significant interaction between IAR and TPCS. Furthermore, the use of a TPCS and/or IAR does not lead to increased operative time and is therefore a reasonable alternative surgical strategy.

Identifying the Superior Reperfusion Technique in Liver Transplantation: A Network Meta-Analysis

Objective

To investigate the clinical effects of different reperfusion techniques in liver transplantation based on network meta-analysis.

Method

Literature retrieval was conducted in globally recognized databases, namely, MEDLINE, EMBASE, and Cochrane Central, to address relative randomized controlled trials (RCTs) investigating the clinical effects of respective reperfusion techniques in liver transplantation. Short- and long-term parametric data, including ICU stay, dysfunction rate (DFR), biliary complications (BC), 1-year graft survival (GS), and patient survival (PS), were quantitatively pooled and estimated based on the Bayesian theorem. The P values of surface under the cumulative ranking (SUCRA) probabilities regarding each parameter were calculated and ranked by various techniques. The Grades of Recommendations Assessment, Development and Evaluation (GRADE) criteria were utilized for the recommendations of evidence from pairwise direct comparisons.

Results

Seven RCTs containing 6 different techniques were finally included for network meta-analysis. The results indicated that retrograde vena cava (RVC) reperfusion possessed the highest possibility of revealing the best clinical effects on DFR (SUCRA, P = 0.93), ICU stay (SUCRA, P = 0.76), and GS (SUCRA, P = 0.44), while portal-arterial reperfusion (simultaneous initialize) seemed to exhibit the most benefits in reducing BC (SUCRA, P = 0.67) and enhancing PS rate (SUCRA, P = 0.48). Moreover, sensitivity analysis with the inconsistency approach clarified the reliability of the main results, and the evidence of the most direct comparisons was ranked low or very low.

Conclusions

Current evidence demonstrated that RVC and portal-arterial reperfusion (simultaneously initialized) revealed superior clinical effects, compared to other interventions. Investigation of these 2 techniques should be a future research direction, and more high-quality RCTs are expected.

Order of liver graft revascularization in deceased liver transplantation: A systematic review and meta-analysis

BACKGROUND

The ideal order for liver graft revascularization during liver transplantation remains unknown. The majority of liver transplant centers prefer portal venous reperfusion followed by arterial reperfusion to shorten the warm ischemia time. The aim of this study was to review the different revascularization techniques used in clinical liver transplantation to identify any potential clinical benefits.

METHODS

A systematic search of 5 databases was performed to identify all available original articles that reported liver transplantation and compared different techniques of reperfusion. The primary outcomes were patient and graft survival. Secondary outcomes were defined by postreperfusion syndrome, primary nonfunction, vascular complications, biliary complications, and retransplantation.

RESULTS

A total of 1,160 patients undergoing liver transplantation from 15 studies were included in this review and meta-analysis. There were no differences regarding the 1-year patient and graft survival for the revascularization techniques. The incidence of primary nonfunction, vascular complications, and retransplantation did not differ between the groups. Although there were no differences regarding biliary complications between the different groups, there were more nonanastomotic strictures in patients with initial portal revascularization (9%) compared with those with simultaneous revascularization (2%; risk ratio 1.07; 95% confidence interval, 1.00-1.14; P = .05; I² = 51%).

CONCLUSION

The order of liver graft revascularization does not influence patient and graft survival. Each revascularization technique offers potential benefits that can be used under specific clinical situations.

The hepatic protective effects of tacrolimus as a rinse solution in liver transplantation: A meta-analysis

BACKGROUND

Tacrolimus was used as a rinse solution against ischaemia-reperfusion injury (IRI) in liver transplantation for years but its protective effects remain controversies.

METHODS

We conducted literature retrieval in electronic databases including MEDLINE, EMBASE and Cochrane Central to identify relevant randomized controlled trials (RCTs) investigating the effects of tacrolimus as a rinse solution in liver transplantation. Postoperative liver function, including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBIL), at postoperative day (POD) 1, 2 and 7 was extracted for pooled estimation. Forest plots were generated to calculate the differences between the groups. The I2 index statistic was used to assess heterogeneity. Publication bias was evaluated using funnel plots and Egger's test.

RESULTS

Three RCTs including 70 liver transplants were evaluated in this study. Pooled estimation revealed that rinse with tacrolimus in liver transplantation did not provide hepatic protection with respect to postoperative ALT (Test Z = 1.36; P = .175), AST (Test Z = 1.70; P = .090) or TBIL (Test Z = 0.69; P = .490). Sensitivity analysis by excluding extended donor criteria (EDC) livers showed similar results. Funnel plots and Egger's test demonstrated that there was no substantial bias.

CONCLUSION

We may tentatively conclude that tacrolimus is ineffective for amelioration of postoperative liver function as a rinse solution in liver transplantation. Nevertheless, there is great space for future research in this area, and the potential clinical value of tacrolimus needs to be further addressed. We are expecting more evidence to support our speculations.

The role of graft reperfusion sequence in the development of non-anastomotic biliary strictures following orthotopic liver transplantation: A meta-analysis

BACKGROUND

Liver transplant is a potential cure for liver failure and hepatic malignancy but there are many techniques which have been described for vascular reconstruction. This study was to compare the prevalence of non-anastomotic biliary stricture and other surgical complications based on Clavien-Dindo scoring system, in initial portal reperfusion (sequential) versus simultaneous or initial artery reperfusion.

DATA SOURCES

Meta-analysis of published studies comparing the outcomes of both techniques was carried out. Data search was conducted across the major databases and studies were selected under the guidance of the Cochrane guidelines for systematic reviews and meta-analysis.

RESULTS

Seven studies were included to address the primary and the secondary outcomes. No statistical difference was found in the incidence of non-anastomotic biliary strictures (OR = 0.40; P = 0.14), regardless of reperfusion technique. The pooled estimate of the Clavien-Dindo grading of complications was not significantly different between the techniques, though Clavien-Dindo II complications were higher in the simultaneous or initial artery reperfusion group than the initial portal reperfusion group (OR = 2.73; P = 0.01). Similarly, there was no difference in the operative time, hospital stay and other outcomes addressed in this report.

CONCLUSIONS

The available evidence suggests that there is no significant difference demonstrated in the rate of non-anastomotic biliary strictures or other complications, between the two techniques, except for Clavien-Dindo II complications.

Splenectomy during whole liver transplantation: a morbid procedure which does not adversely impact long-term survival

BACKGROUND

Indications for splenectomy (SP) during whole liver transplantation (LT) remain controversial and SP is often avoided because of common complications. We aimed to evaluate specific complications of these combined procedures.

METHODS

Data were retrospectively analysed. Splenectomy was performed in patients with splenorenal shunt and/or splenic artery aneurysms or hypersplenism. Patients undergoing simultaneous transplantation and splenectomy (LTSP group) were matched to a non-splenectomy group (LT group).

RESULTS

Between 1994 and 2013, we included 47 and 94 patients in LTSP and LT groups, respectively. The LTSP patients had a higher rate of pre-LT portal vein thrombosis (PVT). The LTSP group had a longer operative time and greater blood loss. Mean follow-up was 101 months and 5-year survivals were identical (LTSP 85% vs LT 88%, p = 0.831). Hospital morbidity and rejection incidence were comparable, whereas de novo PVT (34% vs 2%, p < 0.0001) and infection (47% vs 25%, p = 0.014) rates were higher after SP.

CONCLUSION

Splenectomy during LT is technically demanding and exposes recipients to a higher thrombosis rate, therefore portal vein patency must be specifically assessed postoperatively. In selected recipients, SP can be performed without increased mortality but at the price of worsening outcome as evidenced by greater risk of infection and PVT.

Post reperfusion syndrome during liver transplantation: From pathophysiology to therapy and preventive strategies

This review aims at evaluating the existing evidence regarding post reperfusion syndrome, providing a description of the pathophysiologic mechanisms involved and possible management and preventive strategies. A PubMed search was conducted using the MeSH database, “Reperfusion” AND “liver transplantation” were the combined MeSH headings; EMBASE and the Cochrane library were also searched using the same terms. 52 relevant studies and one ongoing trial were found. The concept of post reperfusion syndrome has evolved through years to a multisystemic disorder. The implications of the main organ, recipient and procedure related factors in the genesis of this complex syndrome are discussed in the text as the novel pharmacologic and technical approaches to reduce its incidence. However the available evidence about risk factors, physiopathology and preventive measures is still confusing, the presence of two main definitions and the numerosity of possible confounding factors greatly complicates the interpretation of the studies.

Crystalloid flush with backward unclamping may decrease post-reperfusion cardiac arrest and improve short-term graft function when compared to portal blood flush with forward unclamping during liver transplantation

During liver transplant (LT), the release of vasoactive substances into the systemic circulation is associated with severe hemodynamic instability that is injurious to the recipient and/or the post-ischemic graft. Crystalloid flush with backward unclamping (CB) and portal blood flush with forward unclamping (PF) are two reperfusion methods to reduce reperfusion-related cardiovascular perturbations in our center. The primary aim of this study was to compare these two methods. After institutional review board (IRB) approval, cadaveric whole LT cases performed between 2003 and 2008 were reviewed. Patients were divided into two groups based on reperfusion methods: CB or PF. After background matching with propensity score, the effect of each method on post-operative graft function was assessed in detail. In our cohort of 478 patients, CB was used in 313 grafts and PF in 165. Thirty-day graft survival was lower, and risk of retransplantation was higher in PF. Multivariable model showed that CB is an independent factor to reduce primary non-function, cardiac arrest and improve 30-d graft survival. Also, the incidence of ischemic-type biliary lesions was significantly higher in the PF group. Reperfusion methods affect intraoperative hemodynamics and post-transplant outcome. CB allows for control over temperature and composition of the perfusate, perfusion pressure, and the rate of infusion.

Hepatic artery kinking during liver transplantation: survey and prospective intraoperative flow measurement

BACKGROUND

Hepatic artery thrombosis (HAT) represents the most common vascular complication occurring after liver transplantation (LT). Herein, we report the results of a prospective study of hepatic artery flow (HAF) measurement during abdominal wall closure after LT along with the results of an international survey of procedures adopted, in order to avoid the arterial kinking (AK) in case of long artery.

METHODS

Sixty-four surgeons were asked regarding the different procedures used to avoid AK in the presence of long artery. We prospectively assessed the HAF during three phases of LT in 26 consecutive LT performed in patients with a long HA: after completion of the biliary anastomosis (M0), and partial abdominal wall closure with (M1w) or without (M1w/o) hepatic artery anti-kinking method (HAAK).

RESULTS

Sixty (93.7 %) surgeons replied to the survey: 44 (73.3 %) surgeons cut the artery as short as possible, of whom 38 (86.3 %) interposed an oxidized polymer or the omentum, and six (13.7 %) used other systems. Fourteen (23.3 %) surgeons did not use any interposition methods. The remaining two (3.3 %) surgeons left a long artery without HAAK. In our cohort we obtained the following HAF measures: M0 152 mL/min (89-205), M1 without HAAK 114 (66-168) and M1 with HAAK procedure 158 (91-219) (p = 0.002).

CONCLUSIONS

Our survey confirms that no consensus is currently available regarding the most effective method for avoiding AK. Kinking occurs most probably when the liver is released in its final position. The utilization of an interposition method could ensure the maintenance of a correct HAF.

Techniques of flushing and reperfusion for liver transplantation

BACKGROUND

Various techniques of flushing and reperfusion have been advocated to improve outcomes after liver transplantation. There is considerable uncertainty as to which method is superior.

OBJECTIVES

To compare the benefits and harms of different methods of flushing and reperfusion during liver implantation in the transplant recipients.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until March 2011.

SELECTION CRITERIA

We included all randomised clinical trials that were performed to compare different techniques of flushing and reperfusion during liver transplantation.

DATA COLLECTION AND ANALYSIS

Two authors independently identified the trials and extracted the data. We analysed the data with both the fixed-effect model and the random-effects model using RevMan analysis. For each outcome we calculated the hazard ratio (HR), risk ratio (RR), rate ratio, mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI) based on available case analysis.

MAIN RESULTS

We included six trials involving 418 patients for this review. The sample size in the trials varied from 30 to 131 patients. Only one trial involving 131 patients was of low risk of bias for mortality. This trial was at high risk of bias for other outcomes. Four trials excluded patients who underwent liver transplantation for acute liver failure. All the trials included livers obtained from cadaveric donors. The remaining five trials were of high risk of bias for all outcomes. Liver transplantation was performed by the conventional method (caval replacement) in two trials and piggy-back method (caval preservation) in one trial. The method of liver transplantation was not available in the remaining three trials. The comparisons performed included an initial hepatic artery flush versus initial portal vein flush; blood venting via inferior vena cava in addition to venting of storage fluid versus no blood venting; initial hepatic artery reperfusion versus initial portal vein reperfusion; simultaneous hepatic artery and portal vein reperfusion versus initial portal vein reperfusion; and retrograde inferior vena cava reperfusion versus simultaneous hepatic artery and portal vein reperfusion. Only one or two trials could be included under each comparison. There was no significant difference in mortality, graft survival, or severe morbidity rates in any of the comparisons. Quality of life was not reported in any of the trials.

AUTHORS' CONCLUSIONS

There is currently no evidence to support or refute the use of any specific technique of flushing or reperfusion during liver transplantation. Due to the paucity of data, absence of evidence should not be confused with evidence of absence of any differences. Further well designed trials with low risk of systematic error and low risk of random errors are necessary.

Anesthetic management of hepatic transplantation

PURPOSE OF REVIEW

The present review describes new trends and ongoing controversies in the anesthetic care of liver transplant recipients.

RECENT FINDINGS

Recent studies have improved our knowledge of conditions increasing perioperative risk, such as portopulmonary hypertension and renal failure. Improved surgical and anesthetic management has reduced intraoperative blood loss, as more studies identify an independent association between blood transfusion and poor outcome. New concepts in the coagulopathy of liver failure are emerging, with clear implications for clinical practice, including greater awareness of the risks of intraoperative thromboembolism. Less invasive intraoperative hemodynamic monitoring has been advocated, as has wider use of transoesophageal echocardiography. Early extubation is becoming more routinized.

SUMMARY

Anesthetic management still varies widely between liver transplant centers with little data to indicate best practice. Future research should focus on fluid replacement, prevention and treatment of coagulopathy, care of the acutely ill patient and the safety and benefits of early extubation.

Reperfusion of the liver allograft with blue blood: is it still the royal perfusate?

The technique of liver transplantation has become relatively standardized. Although not commonly practiced, arterial reperfusion has been shown in both animal and human trials to offer hemodynamic and functional benefits to liver allograft recipients. Whether this is the result of shortening the time to re-establishing arterial perfusion or an effect of the sequence which the liver is revascularized remains unknown. Further randomized clinical trials are needed to answer this question and support our practice of arterial reperfusion.

Hemodynamic profile and tissular oxygenation in orthotopic liver transplantation: Influence of hepatic artery or portal vein revascularization of the graft

We performed a prospective, randomized study of adult patients undergoing orthotopic liver transplantation, comparing hemodynamic and tissular oxygenation during reperfusion of the graft. In 30 patients, revascularization was started through the hepatic artery (i.e., initial arterial revascularization) and 10 minutes later the portal vein was unclamped; in 30 others, revascularization was started through the portal vein (i.e., initial portal revascularization) and 10 minutes later the hepatic artery was unclamped. The primary endpoints of the study were mean systemic arterial pressure and the gastric-end-tidal carbon dioxide partial pressure (PCO(2)) difference. The secondary endpoints were other hemodynamic and metabolic data. The pattern of the hemodynamic parameters and tissue oxygenation values during the dissection and anhepatic stages were similar in both groups At the first unclamping, initial portal revascularization produced higher values of mean pulmonary pressure (25 +/- 7 mm of Hg vs. 17 +/- 4 mm of Hg; P < 0.05) and wedge and central venous pressures. At the second unclamping, initial portal revascularization produced higher values of cardiac output and mean arterial pressure (87 +/- 15 mm of Hg vs. 79 +/- 15 mm of Hg; P < 0.05) and pulmonary blood pressure. Postreperfusion syndrome was present in 13 patients (42.5%) in the arterial group and in 11 patients (36%) in the portal group. During revascularization, the values of gastric and arterial pH decreased in both groups and recovered at the end of the procedure, but were more accentuated in the initial arterial revascularization group. In conclusion, we found that initial arterial revascularization of the graft increases pulmonary pressure less markedly, so it may be indicated for those patients with poor pulmonary and cardiac reserve. Nevertheless, for the remaining patients, initial portal revascularization offers more favorable hemodynamic and metabolic behavior, less inotropic drug use, and earlier normalization of lactate and pH values.

Sequential and simultaneous revascularization in adult orthotopic piggyback liver transplantation

The aim of the study was to assess whether there is a difference in outcome after sequential or simultaneous revascularization during orthotopic liver transplantation (OLT) in terms of patient and graft survival, mortality, morbidity, and liver function. The study population consisted of 102 adult patients with primary full-size piggyback OLT transplanted between January 1998 and December 2001. In 71 patients (70%) the grafts were sequentially reperfused after completion of the portal vein anastomosis and subsequent arterial reconstruction was performed (sequential reperfusion [SeqR] group). In 31 patients (30%) the graft was reperfused simultaneously via the portal vein and hepatic artery (simultaneous reperfusion [SimR] group). Patient and graft survival at 1, 3, and 6 months and at 1 year did not differ between the SeqR group and the SimR group. The red blood cell (RBC) requirements were significantly higher in the SimR group (5.5 units; range 0-20) in comparison to the SeqR group (2 units; range 0-19) (P = 0.02). Apart from a higher number of biliary anastomotic complications and abdominal bleeding complications in the SimR group in comparison to the SeqR group (13% vs. 2% and 19% vs. 6%, respectively; P = 0.06), morbidity was not different between the groups. No differences between the groups were observed regarding the incidence of primary nonfunction (PNF), intensive care unit stay, and acute rejection. This was also true for the severity of rejections. Postoperative recuperation of liver function was not different between the groups. In conclusion, no advantage of either of the 2 reperfusion protocols could be observed in this analysis, especially with respect to the incidence of ischemic type biliary lesions (ITBL).

Techniques of orthotopic liver transplantation

BACKGROUND

Throughout the history of liver transplantation many improvements have been made in the field of surgical technique. It is beyond the scope of this paper to review all aspects of surgical technique in liver transplantation; thus, in this review we focus on the description of our current technique in most cases, which is orthotopic liver transplantation with preservation of the inferior vena cava and temporary portocaval shunt. We advocate this technique because it has been demonstrated that it achieves better haemodynamic stability during the anhepatic phase, transfusion can be reduced and renal function is improved. The different options for vascular anastomoses are described, particularly the options for arterial anastomoses in case of finding a non-adequate recipient hepatic artery. Technical possibilities for patients with preoperative portal vein thrombosis and the procedure in case of domino or sequential liver transplantation are further explained.