Victor W. Xia

Severe Intraoperative Hyperglycemia Is Independently Associated With Surgical Site Infection After Liver Transplantation

Background. Surgical site infection (SSI) is a common postoperative complication associated with increased morbidity and mortality in patients undergoing liver transplantation (LT). Although intraoperative hyperglycemia has been shown to be associated with adverse postoperative outcomes including overall infection rate in LT patients, a relationship between intraoperative hyperglycemia and SSI in LT has not been established. We sought to determine if intraoperative hyperglycemia was associated with SSI after LT. Methods. Patients undergoing LT at our medical center between January 2004 and November 2007 were included in the study. Recipient, donor, and intraoperative variables including a variety of glucose indices were retrospectively analyzed. Independent risk factors of SSI were identified using a multivariate logistic regression model. Results. Of 680 patients, 76 (11.2%) experienced postoperative SSIs. Among all intraoperative glucose indices analyzed, severe hyperglycemia (≥200 mg/dL) was independently associated with postoperative SSI (odds ratio [OR] 2.25, 95% confidence interval [CI] 1.26–4.03, P=0.006). Other independent risk factors include repeat surgery (OR 6.58, 95% CI 3.41–12.69, P<0.001), intraoperative administration of vasopressor (OR 3.14, 95% CI 1.65–5.95, P<0.001), preoperative mechanical ventilation (OR 3.01, 95% CI 1.70–5.33, P<0.001), and combined liver and kidney transplantation (OR 2.95, 95% CI 3.41–12.69, P<0.001). Conclusions. Severe, but not mild or moderate, intraoperative hyperglycemia is independently associated with postoperative SSI and should be avoided during LT surgery.

Preoperative characteristics and intraoperative transfusion and vasopressor requirements in patients with low vs. high MELD scores

Recent changes in organ allocation based on the model for end‐stage liver disease (MELD) prioritize the most ill patients on the waiting list for liver transplantation. While patients undergoing liver transplantation in the MELD era are more acutely ill, the impact of the policy changes on perioperative management has not been completely assessed. We retrospectively reviewed the records of 124 primary adult liver transplant patients. Patients were divided into low (≤30) and high MELD (>30) score groups. Preoperative characteristics and intraoperative management were compared between the 2 groups. Patients with high MELD scores had lower baseline hematocrit and fibrinogen levels and were more likely to require ventilatory and vasopressor support before transplantation. Intraoperative transfusion requirements and use of vasopressors were also significantly increased in patients with high MELD scores compared to patients with low MELD scores. In conclusion, these data suggest that pretransplant MELD scores provide important information for perioperative management of patients undergoing liver transplantation. Liver Transpl 12:614–620, 2006.

Predictors of hyperkalemia in the prereperfusion, early postreperfusion, and late postreperfusion periods during adult liver transplantation

BACKGROUND:Hyperkalemia poses serious hazards to patients undergoing orthotopic liver transplantation (OLT), and its predictors have not been thoroughly examined. METHODS:We retrospectively studied 1124 consecutive adult patients who underwent OLT. Hyperkalemia was defined as serum K+ ≥5.5 mmol/L. A total of 47 recipient, donor, intraoperative, and laboratory variables were initially analyzed in univariate analyses. Independent predictors of hyperkalemia in three periods of OLT (prereperfusion, early postreperfusion, and late postreperfusion) were determined in multivariate logistic regression analyses. RESULTS:Of 1124 patients, 10.2%, 19.1%, and 7.9% had hyperkalemia in the prereperfusion, early postreperfusion, and late postreperfusion periods, respectively. Higher baseline K+ and red blood cell transfusion were independent predictors of prereperfusion hyperkalemia. Higher baseline K+ (or prereperfusion K+) and donation after cardiac death donor were independent predictors of early postreperfusion hyperkalemia. Higher baseline K+, longer warm ischemia time, longer donor hospital stay, lower intraoperative urine output, and the use of venovenous bypass were independent predictors of late postreperfusion hyperkalemia. CONCLUSIONS:Several laboratory, intraoperative, and donor variables were identified as independent predictors of hyperkalemia in the different periods. Such information may be used for more targeted preemptive interventions in patients who are at risk of developing hyperkalemia during adult OLT.

Antifibrinolytics in orthotopic liver transplantation: Current status and controversies

This article reviews the current status and controversies of the 3 commonly used antifibrinolytics—epsilon‐aminocaproic acid, tranexamic acid and aprotinin—during liver transplantation. There is no general consensus on how, when or which antifibrinolytics should be used in liver transplantation. Although these drugs appear to reduce blood loss and decrease transfusion requirements during liver transplantation, their use is not supported uniformly in clinical trials. Aprotinin has been studied more extensively in clinical trials and appear to offer more advantages compared to two other antifibrinolytics. Because of the diverse population of liver transplant recipients and the potential adverse effects of antifibrinolytics, especially life–threatening thromboembolism, careful patient selection and close monitoring is prudent. Further studies addressing the risks and benefits of antifibrinolytics in the setting of liver transplantation are warranted. (Liver Transpl 2005;11:10–18.)

Postliver transplant acute renal injury and failure by the RIFLE criteria in patients with normal pretransplant serum creatinine concentrations: a matched study.

Background. Acute renal injury (ARI) and acute renal failure (ARF) are serious complications after liver transplantation (LT). Few studies apply the risk, injury, function, loss, and end-stage criteria on the patients who have normal preoperative renal function. The aims of this study were to identify the incidence, risk factors, and impact of ARI and ARF in this patient population. Methods. After institutional review board approval, adult LT patients who had preoperative serum creatinine less than or equal to 1.5mmol/L were reviewed. Postoperative ARI and ARF were determined by the risk, injury, function, loss, and end-stage criteria. Risk factors were determined by multivariable regression. Postoperative outcomes were compared among patients with or without ARI or ARF. Results. Among 334 patients included the study, 20.4% and 18.0% had ARI or ARF in the first week after LT, respectively. Then 118 ARI or ARF patients were matched with patients without post-LT renal injury by gender, creatinine, and body mass index. Multivariable analysis showed that increased requirement of red blood cell transfusion (odds ratio [OR] 2.7–8.8, P<0.05), vasopressors (OR 2.2, P=0.018), and pre-LT albumin less than or equal to 3.5 mg/dL (OR: 2.8, P=0.003) as risk factors for post-LT ARI or ARF. Both ARI and ARF were associated with longer hospital stay and higher reoperation rate. ARF, but not ARI, was associated with higher 30-day graft failure and mortality rates. Conclusion. Post-LT ARI or ARF occurred frequently in patients with normal preoperative renal function and was associated with both preoperative and intraoperative risk factors. Although both post-LT ARI and ARF are associated with significant post-LT morbidity, the impact of ARF is greater.

The changing face of patients presenting for liver transplantation

Purpose of reviewSignificant changes have been witnessed recently in patients presenting for liver transplantation. The growing number of liver transplantations performed, the increasingly successful outcomes, the expansion of indications, and the implementation of the Model for End-Stage Liver Disease (MELD) system are driving forces for those changes. The purpose of this review is to examine those changes and their effect in perioperative management. Recent findingsPatients who present for liver transplantation today have higher MELD scores and more advanced liver disease. Studies show that high MELD score patients are associated with high perioperative risks and undergo a more difficult perioperative course than patients with low MELD score. More specifically, they have more preoperative comorbidities, more baseline laboratory abnormalities, and higher requirements for intraoperative transfusion and vasopressors. Progress has been also made in management in patients with hepatocellular carcinoma, fulminant hepatic failure, and coronary artery disease prior to liver transplantation. SummaryPatients who present for liver transplantation today are more acutely ill compared with a few years ago and have more comorbidities, higher perioperative risks, and a more difficult perioperative course. Further characterization of the changes and associated perioperative risks and strategies to manage those risks are needed.

Factors associated with hepatic fibrosis in patients with chronic hepatitis C: a retrospective study of a large cohort of U.S. Patients.

Goals To determine the risk factors for stage 3 and 4 fibrosis in a large cohort of U.S. patients with chronic hepatitis C (CHC). Background Multiple host and viral factors affect the outcomes of CHC. Further defining the pathogenic roles of these factors in CHC progression will lead to improving management of this disease. Study Retrospective study of a large cohort of US patients with CHC. Results Of the 460 patients, 331 were males and 129 were females with mean age of 48.4±8.0 years, and 191 (41.7%) had stage 3 and 4 fibrosis. Clinically, a multivariate analysis revealed that age of ≥60 years at presentation, the estimated duration of hepatitis C virus (HCV) infection ≥25 years, a body mass index ≥30 kg/m2, and a history of diabetes mellitus were independently associated with stage 3 and 4 fibrosis, after adjusting for history of alcohol use. Laboratorially, a multivariate analysis revealed that aspartate aminotransferase (AST) ≥2×upper limit of normal (ULN), alpha fetoprotein ≥15 μg/L, and presence of grade 2 and 3 steatosis were independently associated with stage 3 and 4 fibrosis, after adjusting for alanine aminotransferase ≥2×upper limit of normal, AST/alanine aminotransferase ratio ≥1, HCV genotyping, transferrin saturation, and a histology activity index score ≥7. Conclusions The present study indicated that elderly, longer duration of HCV infection, obesity, and history of diabetes mellitus are independent clinical parameters associated with advanced fibrosis, whereas elevated AST, alpha fetoprotein, and presence of grade 2 and 3 steatosis are independent laboratorial parameters associated with stage 3 and 4 fibrosis in patients with CHC.

Clinical presentation of chronic hepatitis C in patients with end-stage renal disease and on hemodialysis versus those with normal renal function

BACKGROUND:The natural history of chronic hepatitis C (CHC) remains to be defined in patients with end-stage renal disease (ESRD).AIMS:To determine the clinical presentation of CHC and the factors associated with stage III-IV fibrosis in patients with CHC and ESRD.METHODS:The study included patients with CHC and ESRD (n = 91) or normal renal function (NRF, n = 159). Both groups were matched for mean age, gender, history of alcohol use, and estimated duration of hepatitis C virus (HCV) infection.RESULTS:Presentation of CHC and ESRD was independently associated with non-Caucasian ethnicity (OR = 3.24, p= 0.0003), a history of diabetes mellitus (DM, OR = 7.911, p < 0.0001), and lower frequencies of being obese (OR = 0.457, p= 0.035), of having hepatic steatosis (OR = 0.372, p= 0.003), and stage III-IV fibrosis (OR = 0.403, p= 0.016). After adjusting for serum levels of alpha-fetoprotein (AFP) and HCV RNA, CHC, and ESRD were independently associated with lower frequencies of elevated alanine aminotransferase (ALT, OR = 0.175, p= 0.02) and aspartate aminotransferase (AST, OR = 0.169, p= 0.04), but higher frequencies of AST/ALT ratio >1 (OR = 7.173, p= 0.002) and hypoalbuminemia (OR = 9.567, p= 0.0007). Compared to patients with NRF and stage III-IV fibrosis, those with ESRD and stage III-IV fibrosis had a significantly higher frequency of a history of DM (OR = 8.014, p= 0.0031) and lower frequency of elevated AST (OR = 0.054, p= 0.004), which were independent of the frequencies of lower levels of ALT and albumin, and AST/ALT ratio >1. In patients with CHC and ESRD, the presence of stage III-IV fibrosis was significantly associated with hepatic steatosis (OR = 4.523, p= 0.012) and thrombocytopenia (OR = 4.884, p= 0.044), which were independent of the frequencies of a history of DM, splenomegaly, and a higher level of AST.CONCLUSIONS:CHC and ESRD are independently associated with a higher frequency of a history of DM, but lower frequencies of being obese, and having hepatic steatosis, stage III-IV fibrosis, and elevated transaminases. In patients with CHC and ESRD, stage III-IV fibrosis is not associated with a history of DM, but is independently associated with hepatic steatosis and thrombocytopenia.

Incidental intracardiac thromboemboli during liver transplantation: Incidence, risk factors, and management

Even though numerous cases of massive thromboemboli have been reported in the literature, intracardiac thromboemboli (ICTs) incidentally found during orthotopic liver transplantation (OLT) have not been examined. In this study, we retrospectively examined the incidence, risk factors, and management of incidental ICTs during OLT. After institutional review board approval, adult patients who underwent OLT between January 2004 and December 2008 at our center were reviewed. ICTs were identified and confirmed by the examination of OLT datasheets, anesthesia records, and recorded transesophageal echocardiography (TEE) clips. The clinical presentation, management, and outcomes of the patients with ICTs were reviewed. Risk factors were analyzed by multivariate logistic regression. During the study period, 426 of the 936 adult OLT patients (45.5%) underwent intraoperative TEE monitoring. Incidental ICTs were identified in 8 of these 426 patients (1.9%). Two ICTs occurred before reperfusion, and 6 ICTs occurred after reperfusion. The treatment was at the discretion of the treating physicians; however, none of the patients received an anticoagulant or thrombolytics. Multivariate analysis identified 2 independent risk factors for intraoperative incidental ICTs: the presence of symptomatic or surgically treated portal hypertension (a history of gastrointestinal bleeding, a transjugular intrahepatic portosystemic shunt procedure, or portocaval shunt surgery) before OLT and intraoperative hemodialysis (odds ratios of 4.05 and 7.29, respectively; P < 0.05 for both). In conclusion, incidental ICTs during OLT occurred at a rate of 1.9% and were associated with several preoperative and intraoperative risk factors. The use of TEE allows early identification, which may be important. Our management for incidental ICTs is described; however, no conclusions can be made about the optimal therapy. Liver Transpl 16:1421–1427, 2010.

Liver Transplantation in Recipients Receiving Renal Replacement Therapy: Outcomes Analysis and the Role of Intraoperative Hemodialysis

The Model for End‐Stage Liver Disease (MELD) system has dramatically increased the number of recipients requiring pretransplant renal replacement therapy (RRT) prior to liver transplantation (LT). Factors affecting post‐LT outcomes and the need for intraoperative RRT (IORRT) were analyzed in 500 consecutive recipients receiving pretransplant RRT, including comparisons among recipients not receiving IORRT (No‐IORRT, n = 401), receiving planned IORRT (Pl‐IORRT, n = 70), and receiving emergent, unplanned RRT after LT initiation (Em‐IORRT, n = 29). Despite a median MELD of 39, overall 30‐day, 1‐, 3‐ and 5‐year survivals were 93%, 75%, 68% and 65%, respectively. Em‐IORRT recipients had significantly more intraoperative complications (arrhythmias, postreperfusion syndrome, coagulopathy) compared with both No‐IORRT and Pl‐IORRT and greater 30‐day graft loss (28% vs. 10%, p = 0.004) and need for retransplantation (24% vs. 10%, p = 0.099) compared with No‐IORRT. A risk score based on multivariate predictors of IORRT accurately identified recipients with chronic (sensitivity 84%, specificity 72%, concordance‐statistic [c‐statistic] 0.829) and acute (sensitivity 93%, specificity 61%, c‐statistic 0.776) liver failure requiring IORRT. In this largest experience of LT in recipients receiving RRT, we report excellent survival and propose a practical model that accurately identifies recipients who may benefit from IORRT. For this select group, timely initiation of IORRT reduces intraoperative complications and improves posttransplant outcomes.