Hemodynamics and vasoactive substance levels during renal congestion that occurs in the anhepatic phase of liver transplantation

Effects of Peroperative Cold Ischemia Time and Anhepatic Phase in Adult Living Donor Liver Transplant Recipients: Operation Time That is Not Affected by the Anhepatic Phase But is Prolonged by Cold Ischemia Time

OBJECTIVE

It was aimed to examine the overall role of cold ischemia time and anhepatic phase durations in terms of peroperative blood transfusion needs, hospital stay conditions and postoperative charges, and survival in recipients.

MATERIAL AND METHODS

One hundred forty-eight adult living donor liver transplant recipients (18 years and older) were included in the study. Whether the anhepatic phase and cold ischemia duration have an effect on the rates of surgery time, blood product transfusion, total hospital and intensive care unit stay, postoperative biliary complications, hepatic vein thrombosis, portal vein thrombosis, early postoperative bleeding, sepsis, and primary graft dysfunction. Was analyzed statistically. In addition, the effect of the anhepatic phase and cold ischemia time on graft survival was statistically examined by creating an average of the patient follow-up period.

RESULTS

It was observed that the operation time increased statistically as the cold ischemia time increased (P = .000). No statistically significant relationship was found between other findings and cold ischemia time and anhepatic phase.

CONCLUSION

Prolonged surgery time due to increased cold ischemia time may be an important finding in terms of peroperative and postoperative results of the graft.

Hemodynamics in nutcracker syndrome: implications for diagnosis

BACKGROUND

Nutcracker syndrome is a disease characterized by complex symptoms, making its diagnosis challenging and often delayed, often resulting in a painful experience for the patients.

OBJECTIVE

This study aimed to investigate the pathogenesis of nutcracker syndrome through the perspective of hemodynamics by simulating blood flow with varying compression degrees of the left renal vein.

METHODS

3D patient-specific vascular models of the abdominal aorta, superior mesenteric artery and left renal vein were constructed based on CT images of patients suspected of having nutcracker syndrome. A hemodynamic simulation was then conducted using computational fluid dynamics to identify the correlation between alterations in hemodynamic parameters and varying degrees of compression.

RESULTS

The study indicated the presence of an evident gradient in velocity distribution over the left renal vein with relatively high degrees of stenosis (α ≤ 50°), with maximum velocity in the central region of the stenosis. Additionally, when the compression degree of the left renal vein increases, the pressure distribution of the left renal vein presents an increasing number of gradient layers. Furthermore, the wall shear stress shows a correlation with the variation of blood flow velocity, i.e., the increase of wall shear stress correlates with the acceleration of the blood flow velocity.

CONCLUSIONS

Using computational fluid dynamics as a non-invasive instrument to obtain the hemodynamic characteristics of nutcracker syndrome is feasible and could provide insights into the pathological mechanisms of the nutcracker syndrome supporting clinicians in diagnosis.

Incidence and Risk Factors of Acute Kidney Injury in Pediatric Liver Transplant Patients: A Retrospective Study

Background

Acute kidney injury (AKI) significantly contributes to the mortality and morbidity rates among pediatric liver transplant (LT) recipients.

Objective

Our study aimed to assess the potential factors contributing to AKI in pediatric LT patients and to analyze the impact of AKI on postoperative mortality and hospitalization duration.

Materials and methods

About 235 pediatric LT patients under the age of 18 between the years 2015 and 2021 were evaluated retrospectively. The relationship between preoperative and intraoperative variables of the patients and AKI developed when the early postoperatıve period was assessed.

Results

A correlation was found between the patients' preoperative age, albumin levels, and AKI. AKI was found to be associated with the duration of surgery and intraoperative blood transfusion.

Conclusion

Our findings revealed that the severity of AKI in pediatric LT patients is linked to extended surgical durations and increased blood transfusions resulting from hemodynamically compromised blood loss. Furthermore, independent risk factors for AKI were identified as prolonged warm ischemia and the overall duration of the operation.

How to cite this article

Demiroz D, Colak YZ, Ozdes OO, Ucar M, Ali Erdogan M, Toprak HI, et al. Incidence and Risk Factors of Acute Kidney İnjury in Pediatric Liver Transplant Patients: A Retrospective Study. Indian J Crit Care Med 2024;28(1):75-79.

Acute Kidney Injury After Liver Transplant: Incidence, Risk Factors, and Impact on Patient Outcomes

OBJECTIVES

Acute kidney injury is a frequent complication of liver transplant. Here, we assessed the rate and contributing factors of acute kidney injury and need for renal replacement therapy in patients undergoing liver transplant at a transplant center in Tehran, Iran.

MATERIAL AND METHODS

We identified all patients who underwent liver transplant at the Imam Khomeini Hospital Complex from March 2018 to March 2019 and who were followed for 3 months after transplant. Acute kidney injury was defined based on the Acute Kidney Injury Network criteria. We collected demographic and pretransplant, intraoperative, and posttransplant data. Univariable and multivariable models were applied to explore independent risk factors for acute kidney injury incidence and need for renal replacement therapy.

RESULTS

Our study included 173 deceased donor liver transplant recipients. Rates of incidence of acute kidney injury and need for renal replacement therapy were 68.2% and 14.5%, respectively. The 3-month mortality rate among those with severe and mild or moderate acute kidney injury was 44.0% (14/25) and 9.7% (9/ 93), respectively (P < .001). Multivariable analyses indicated that serum albumin (relative risk of 0.55; 95% confidence interval, 0.34-0.87; P = .021), baseline serum creatinine (relative risk of 2.11; 95% confidence interval, 1.56-2.90; P = .037), and intraoperative mean arterial pressure (relative risk of 0.76; 95% confidence interval, 0.63-0.82; P = .008) were independent factors for predicting posttransplant acute kidney injury. Independent risk factors for requiring renal replacement therapy were pretransplant serum creatinine (relative risk of 1.99; 95% confidence interval, 1.89-4.47; P = .044) and intraoperative vasopressor infusion (relative risk of 1.41; 95% confidence interval, 1.38-2.00; P = .021).

CONCLUSIONS

We found a high incidence of acute kidney injury among liver transplant recipients in our center. There was a significant association between severity of acute kidney injury and 3-month and in-hospital mortality.

Renal vein measurement using ultrasonography in patients with cirrhotic ascites and congestive heart failure

PURPOSE

Ascites can cause compression of the inferior vena cava (IVC), leading to increased renal venous pressure and renal congestion. Previously, the left renal vein diameter in liver cirrhosis patients with ascites was measured using computed tomography, showing that enlargement of the left renal vein diameter affects the prognosis. Herein, the diameter and flow velocity of the renal veins were measured using ultrasonography.

METHODS

Abdominal ultrasonography was performed on 186 patients. The patients were divided into four groups: normal liver (n = 102), liver cirrhosis (LC) without ascites (n = 37), LC with ascites (n = 30), and congestive liver (n = 17). Ultrasonographic measurements for diameter and flow velocity of the IVC, left renal vein main trunk, and segmental renal vein were performed.

RESULTS

The left renal vein diameter increased in the following order: normal liver, LC, LC with ascites, and congestive liver groups (P < 0.001). IVC flow velocity was lower and left renal vein diameter was larger in the congestive liver and LC with ascites groups. These results suggest that the two groups have different pathological conditions, but the mechanism of renal congestion is similar. In patients with LC, IVC compression due to ascites might cause blood stagnation and renal congestion.

CONCLUSION

The left renal vein and IVC can be measured using ultrasonography. It might help in furthering our understanding of the pathophysiology of renal congestion in these patients.

Risk factors and associated outcomes of early acute kidney injury in pediatric liver transplant recipients: A retrospective study

BACKGROUND

Acute kidney injury (AKI) may contribute to high mortality rates after liver transplantation. Few studies have investigated AKI in pediatric liver transplantation. This retrospective study was conducted to investigate the risk factors for and associated outcomes of AKI in pediatric liver transplant recipients.

METHODS

Eighty pediatric liver transplant patients were included. The occurrence of AKI was defined by the KDIGO Clinical Practice Guidelines for Acute Kidney Injury. A multivariate regression analysis model was used to investigate risk factors for AKI in the pediatric liver recipients.

RESULTS

The final multivariable regression model showed that biliary atresia (odds ratio [OR] = 0.097, p = 0.03), increased time of the anhepatic phase (OR = 0.871, p = 0.005) and lower postoperative jaundice clearance (OR = 13.936, p = 0.02) were independently associated with the development of AKI in pediatric patients. Additionally, cumulative 3-year patient (p = 0.15) and graft (p = 0.26) survival rates between the non-acute kidney injury (NAKI) and AKI groups were 95.2% vs 86.8% and 90.5% vs 84.2%, respectively.

CONCLUSION

Pediatric liver transplant recipients with a presence of biliary atresia, increased time of anhepatic phase, and a lower postoperative jaundice clearance had an increased risk of AKI. The long-term outcomes of patients who developed AKI appears to be worse compared with those having NAKI.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

Level III.

Non-invasive cardiac output measurement with electrical velocimetry in patients undergoing liver transplantation: comparison of an invasive method with pulmonary thermodilution

BACKGROUND

The goal of this study was to evaluate the accuracy and interchangeability between continuous cardiac output (CO) measured by electrical velocimetry (CO_Ev) and continuous cardiac output obtained using the pulmonary thermodilution method (CO_PAC) during living donor liver transplantation (LDLT).

METHOD

Twenty-three patients were enrolled in this prospective observational study. CO was recorded by both two methods and compared at nine specific time points. The data were analyzed using correlation coefficients, Bland-Altman analysis for the percentage errors, and the concordance rate for trend analysis using a four-quadrant plot.

RESULTS

In total, 207 paired datasets were recorded during LDLT. CO data were in the range of 2.8-12.7 L/min measured by PAC and 3.4-14.9 L/min derived from the EV machine. The correction coefficient between CO_PAC and CO_Ev was 0.415 with p < 0.01. The 95% limitation agreement was - 5.9 to 3.4 L/min and the percentage error was 60%. The concordance rate was 56.5%.

CONCLUSIONS

The Aesculon™ monitor is not yet interchangeable with continuous thermodilution CO monitoring during LDLT.

TRIAL REGISTRATION

The study was approved by the Institutional Review Board of Chang Gung Medical Foundation in Taiwan (registration number: 201600264B0 ).

Incidence and outcomes of acute kidney injury in patients with hepatocellular carcinoma after liver transplantation

PURPOSE

To describe the incidence and outcomes linked with acute kidney injury (AKI) after liver transplantation (LT) in hepatocellular carcinoma (HCC) patients.

METHODS

From January 2003 to February 2011, HCC patients undergoing LT were retrospectively enrolled. Patient with a glomerular filtration rate (GFR) <60 mL/min/1.73 m² was excluded. AKI was defined and classified according to the AKIN criteria.

RESULTS

Of the 566 eligible patients, AKI was found in 109 (19.26%) patients (stage I, 66 cases; stage II, 15 cases; and stage III, 28 cases). Risk factors for AKI were the long anhepatic time (OR = 3.59, P = 0.009) and prolonged duration of systolic blood pressure (SBP) < 90 mmHg (OR = 1.07, P < 0.0001). Post-LT AKI was an independent risk factor associated with 30-day mortality (HR = 4.05, P = 0.047). Complete recovery occurred in 84 (77.06%) of all AKI episodes within 1 month after operation, while 25 patients (22.94%) suffered from prolonged AKI. Patients with prolonged AKI had a poorer 1-year survival than those with transient AKI (40 vs 86.90%; P < 0.0001). Patients with severe AKI more often developed prolonged AKI. 13 patients (52%) of the prolonged AKI progressed to chronic kidney disease (CKD) defined as eGFR <60 mL/min/1.73 m² after 1 year post-operation.

CONCLUSIONS

Post-LT AKI is not an uncommon complication. Intra-operative hemodynamic instability is crucial in the development of post-LT AKI and deserves more attention. Most post-LT AKI is transient and reversible, while the prolonged form may predict a decrease survival.