Hemodynamics in the immediate post-transplantation period in alcoholic and viral cirrhosis

Utility of the central venous-to-arterial CO2 difference to predict adverse outcomes after liver transplantation

OBJECTIVE

Test whether the development of abnormal venous-to arterial CO₂ difference (ΔPCO₂) during the early phases of postoperative care after a liver transplantation (LT) is related to multi-organ dysfunction and outcomes.

MATERIALS AND METHODS

Prospective cohort study accomplished in a mixed intensive care unit (ICU) at a university hospital. We included 150 eligible patients after a LT between 2015 and 2018. Patients were classified in four predefined groups according to the ΔPCO₂ evolution during the first 6 h of resuscitation: (1) persistently normal ΔPCO₂ (normal at T0 and T6); (2) decreasing ΔPCO₂ (high at T0, normal at T6); (3) increasing ΔPCO₂ (normal at T0, high at T6); and (4) persistently high ΔPCO₂ (high at T0 and T6). Multiorgan dysfunction at day-3 was compared for predefined groups and a Kaplan Meier curve was constructed to show the survival probabilities using a log-rank test to evaluate differences between groups. A Spearman-Rho was used to test the agreement between cardiac output and ΔPCO₂.

RESULTS

There were no significant differences between the study groups regarding higher SOFA scores at day-3 (P = .86), Δ-SOFA (P = .088), as well as global mortality rates (χ² = 5.72; P = .126) and mortality rates at day-30 (χ² = 2.23; P = .5252). A significantly poor inverse agreement between cardiac output and ΔPCO₂ was observed (r2 -0,17; P = ,002) at different points of resuscitation.

CONCLUSIONS

After a LT, central venous-to-arterial CO2 difference was not associated with survival or postoperative adverse outcomes in a critical care patients population.

Echocardiographic assessment of cardiovascular function and clinical outcomes in liver transplant recipients

BACKGROUND & AIMS

Cardiovascular disease contributes to a high rate of morbidity and mortality after liver transplantation (LT). However, the progression of cardiac function and cardiac remodeling in LT recipients remains poorly understood. This study sought to evaluate the progression of cardiac function and structure in LT recipients and identify independent predictors of prognosis using echocardiography.

METHODS

From 2009 to 2019, 178 adult LT recipients at a tertiary academic transplant center were retrospectively studied. Transthoracic echocardiograms 1-year pre- and post-LT were assessed. Primary outcomes were progression of systolic and diastolic function. Secondary outcomes included left ventricular remodeling, all-cause mortality, and heart failure readmission post-LT. Subgroup analyzes were performed for etiology of native liver disease. A multivariable model was constructed to examine independent predictors of outcomes.

RESULTS

Systolic function significantly worsened, with reduction in stroke volume (45-37 ml/m² , p < .001), left ventricular ejection fraction (LVEF) (65%-62%, p < .001) and cardiac index (3.00-2.60 L/min/m² , p < .001). Conversely, there were significant improvements in diastolic indices, including tricuspid regurgitation V_max (228-215 cm/s, p = .017), left atrial volume index (LAVI) (32-26 ml/m² , p < .001) and right ventricular systolic pressure (RVSP) (31-28 mmHg, p = .001). Additionally, patients had increased relative wall thickness (RWT) (p < .001) and decreased left ventricular end-diastolic dimension/body surface area (p < .001) post-LT. The independent predictors for all-cause mortality and heart failure were increased pre-LT mitral annular early diastolic velocity (HR 1.11, CI 1.02-1.22, p = .018), LAVI (HR 1.06, CI 1.02-1.11, p = .007) and decreased LVEF (HR .89, CI .82-.97, p = .006). The effect of non-alcoholic steatohepatitis on cardiovascular outcomes post-LT was largely comparable to that of Hepatitis B.

CONCLUSION

This study showed reduced systolic and improved diastolic function in LT recipients and highlighted the utility of pre-LT echocardiogram in the prognostication and risk stratification of LT candidates.

Effect of post-operative goal-directed fluid therapy (GDFT) on organ function after orthotopic liver transplantation: Secondary outcome analysis of the COLT randomised control trial

BACKGROUND

Goal-directed fluid therapy (GDFT) has been shown to reduce the complications following a variety of major surgical procedures, possibly mediated by improved organ perfusion and function. We have shown that it is feasible to randomise patients to GDFT or standard fluid management following liver transplant in the cardiac-output optimisation following liver transplantation (COLT) trial. The current study compares end organ function in patients from the COLT trial who received GDFT in comparison to those receiving standard care (SC) following liver transplant.

METHODS

Adult patients with liver cirrhosis undergoing liver transplantation were randomised to GDFT or SC for the first 12 h following surgery as detailed in a published trial protocol. GDFT protocol was based on stroke volume (SV) optimisation using 250 ml crystalloid boluses. Total fluid administration and time to extubation were recorded. Hourly SV and cardiac output (CO) readings were recorded from the non-invasive cardiac output monitoring (NICOM) device in both groups. Pulmonary function was assessed by arterial blood gas (ABG) and ventilatory parameters. Lung injury was assessed using PaO₂:FiO₂ ratios and calculated pulmonary compliance. The KDIGO score was used for determining acute kidney injury. Renal and liver graft function were assessed during the post-operative period and at 3 months and 1-year.

RESULTS

60 patients were randomised to GDFT (n = 30) or SC (n = 30). All patients completed the 12 h intervention period. GDFT group received a significantly higher total volume of fluid during the 12 h trial intervention period (GDFT 5317 (2335) vs. SC 3807 (1345) ml, p = 0.003); in particular crystalloids (GDFT 3968 (2073) vs. SC 2510 (1027) ml, p = 0.002). There was no evidence of significant difference between the groups in SV or CO during the assessment periods. Time to extubation, PaO2: FIO₂ ratios, pulmonary compliance, ventilatory or blood gas measurements were similar in both groups. There was a significant rise in serum creatinine from baseline (77 μmol/L) compared to first (87 μmol/L, p = 0.039) and second (107 μmol/L, p = 0.001) post-operative days. There was no difference between GDFT and SC in the highest KDIGO scores for the first 7 days post-LT. At 1-year follow-up, there was no difference in need for renal replacement therapy or graft function.

CONCLUSIONS

In this randomised trial of fluid therapy post liver transplant, GDFT was associated with an increased volume of crystalloids administered but did not alter early post-operative pulmonary or renal function when compared with standard care.

Copeptin (CTproAVP) - A Biomarker of a Circulatory Impairment in Liver Transplant Recipients? A Prospective, Observational Study

BACKGROUND

Copeptin, an easily measured and stable surrogate marker of arginine vasopressin, is a biomarker of a homeostasis disorder and a circulatory impairment in a wide spectrum of morbidities. The aim of this study was to evaluate the potential of copeptin as a biomarker of a circulatory impairment in patients undergoing liver transplantation (LT).

METHODS

This was a prospective, observational study. Blood samples were obtained from 38 patients undergoing LT. Serum copeptin level was measured by means of a sandwich immunoassay pre-, intra-, and postoperatively up to 21 days after the operation.

RESULTS

The mean concentration of copeptin remained in the range of values slightly below 1000 pg/mL during the analyzed observation period and remained higher than the values observed in healthy individuals. Intraoperative and immediately postoperative copeptin levels did not correlate with hemodynamic parameters. There was also no correlation between preoperative copeptin levels (C1) and preoperative Model for End-Stage Liver Disease scores, serum creatinine levels, plasma transaminase levels, international normalized ratio, or hematocrit (Spearman ρ, P > .05).

CONCLUSIONS

Preoperative copeptin levels are elevated in most LT recipients and remain elevated for 21 days after surgery. There was no correlation between the concentration of copeptin and the Model for End-Stage Liver Disease-Sodium score or the cause of a hepatic failure. It cannot be concluded that copeptin is a biomarker of a circulatory impairment in patients with transplanted liver in the perioperative period. The secretion of vasopressin, as measured by copeptin concentration during and after LT, requires further study.

Rupture Risk of Intracranial Aneurysm and Prediction of Hemorrhagic Stroke after Liver Transplant

Postoperative hemorrhagic stroke (HS) is a rare yet devastating complication after liver transplantation (LT). Unruptured intracranial aneurysm (UIA) may contribute to HS; however, related data are limited. We investigated UIA prevalence and aneurysmal subarachnoid hemorrhage (SAH) and HS incidence post-LT. We identified risk factors for 1-year HS and constructed a prediction model. This study included 3544 patients who underwent LT from January 2008 to February 2019. Primary outcomes were incidence of SAH, HS, and mortality within 1-year post-LT. Propensity score matching (PSM) analysis and Cox proportional hazard analysis were performed. The prevalence of UIAs was 4.63% (n = 164; 95% confidence interval (CI), 3.95–5.39%). The 1-year SAH incidence was 0.68% (95% CI, 0.02–3.79%) in patients with UIA. SAH and HS incidence and mortality were not different between those with and without UIA before and after PSM. Cirrhosis severity, thrombocytopenia, inflammation, and history of SAH were identified as risk factors for 1-year HS. UIA presence was not a risk factor for SAH, HS, or mortality in cirrhotic patients post-LT. Given the fatal impact of HS, a simple scoring system was constructed to predict 1-year HS risk. These results enable clinical risk stratification of LT recipients with UIA and help assess perioperative HS risk before LT.

Hemodynamic Changes and Early Recovery of Liver Graft Function after Liver Transplantation

BACKGROUND

Patients with liver cirrhosis experience a hyperdynamic circulation.

OBJECTIVE

To investigate the association between early hemodynamic changes and graft function after liver transplant.

METHODS

Those patients who underwent liver transplantation in 2016 were enrolled in the study. Liver function indices measured in postoperative days (POD) 1, 3, 5, 7, 9, and 11 along with hemodynamic indices including pulse rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), and central venous pressure (CVP) measured q6h in the first 3 days after transplantation were recorded.

RESULTS

57 deceased-donor liver recipients with a mean±SD age of 41.4±11.8 years including 33 (58%) males were enrolled in the study. The mean±SD aspartate and alanine aminotransferases, alkaline phosphatase, and lactate dehydrogenase were significantly decreased from 1879±670.5, 369.2±40.5, 174.9±18.8, and 1907.6±323.1 U/L in POD 1 to 37.2±10.7, 243.4±37.3, 207.5±19.5, and 382.4±59.8 U/L in POD 3, respectively (p=0.028, <0.001, 0.002, and 0.001, respectively). During this period, the pulse rate of the patients was significantly (p<0.001) decreased by a median (IQR) of 28.7 (8.5-39.7) beats/min; it was significantly correlated with a decrease in serum hepatic enzymes activities during this period. SBP, DBP, and CVP were significantly increased (p<0.001 for all) during this period. Liver graft function improved significantly earlier in those patients with a mean pulse rate of 87 beats/min compared with others (p=0.03).

CONCLUSIONS

There may be an association between changes of hemodynamic indices, especially reduction of pulse rate, and improved graft function early after liver transplantation.

Liver Transplantation

The field of liver transplantation has changed since the MELD scoring system became the most widely used donor allocation tool. Due to the MELD-based allocation system, sicker patients with higher MELD scores are being transplanted. Persistent organ donor shortages remain a challenging issue, and as a result, the wait-list mortality is a persistent problem for most of the regions. This chapter focuses on deceased donor and live donor liver transplantation in patients with complications of portal hypertension. Special attention will also be placed on donor-recipient matching, perioperative management of transplant patients, and the impact of hepatic hemodynamics on transplantation.

Pulmonary vascular resistance index: Getting the units right and why it matters

Pulmonary vascular resistance (PVR) and PVR index (PVRI) are key variables in a broad range of contexts, including prediction of outcomes in heart and liver transplantation, determining candidacy for closure of atrial or ventricular septal defects, and guiding treatment of pulmonary hypertension. Significant variability exists among the units used to report PVRI in current literature, making the interpretation of data and translation into clinical practice difficult. Here, we will review the measurement and derivation of PVR and PVRI and demonstrate the extent of confusion in the literature. We conducted a literature search of all published articles in PubMed using the term “PVRI.” This yielded 218 sources with defined units for PVRI, including 33 unique variants. Among all reviewed literature, 45.4% of sources reported PVRI with units ending in m² (meters squared), which we defined as correct, whereas 54.6% reported PVRI with units not ending in m², which we defined as incorrect. This lack of uniformity has led to considerable confusion among researchers and clinicians, with potentially life‐altering consequences.

Cardiac output Optimisation following Liver Transplant (COLT) trial: study protocol for a feasibility randomised controlled trial

Background

Patients with liver cirrhosis undergoing liver transplantation have a hyperdynamic circulation which persists into the early postoperative period making accurate assessment of fluid requirements challenging. Goal-directed fluid therapy (GDFT) has been shown to reduce morbidity and mortality in a number of surgery settings. The impact of GDFT in patients undergoing liver transplantation is unknown. A feasibility trial was designed to determine patient and clinician support for recruitment into a randomised controlled trial of GDFT following liver transplantation, adherence to a GDFT protocol, participant withdrawal, and to determine appropriate endpoints for a subsequent larger trial to evaluate the efficacy of GDFT in patients undergoing liver transplantation.

Methods

The Cardiac output Optimisation following Liver Transplant (COLT) trial is designed as a prospective, single-centre, randomised controlled study to assess the feasibility and safety of GDFT in liver transplantation for patients with cirrhosis. Consenting adults (aged between 18 and 80 years) with biopsy-proven liver cirrhosis who have been selected to undergo a first liver transplantation will be included in the trial and randomised into GDFT or standard care starting immediately after surgery and continuing for the first 12 h thereafter. Both groups will have cardiac output and stroke volume monitored using the FloTrac (EV1000) device. The intervention will consist of a protocolised GDFT approach to patient management, using stroke volume optimisation. The control group will receive standard care, without stroke volume and cardiac output measurement. After 12 h the patient’s fluid management will revert to standard of care. The primary endpoint of this study is feasibility. Secondary endpoints will include a safety assessment of the intervention, graft and patient survival, liver function, postoperative complications graded by Clavien-Dindo criteria, length of intensive care and hospital stay and quality of life across the intervention and control groups.

Discussion

There is a growing body of evidence that the use of perioperative GDFT in surgical patients can improve outcomes; however, signals of harm have also been detected. Patients with liver cirrhosis undergoing liver transplantation have markedly different cardiovascular physiology than general surgical patients. If GDFT is proven to be feasible and safe in this patient group, then a multicentre trial to demonstrate efficacy and cost-effectiveness will be required.

Trial registration

International Standard Randomised Controlled Trial Registry, ID: ISRCTN10329248. Registered on 4 April 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2488-8) contains supplementary material, which is available to authorized users.

High Flow-Mediated Vasodilatation Predicts Pulmonary Edema in Liver Transplant Patients

BACKGROUND

Early pulmonary edema is common after orthotopic liver transplantation. Associated pathogenic mechanisms might involve increased activity of cardiac-inhibitory systems due to increased vasodilator production, mainly nitric oxide (NO). NO is primarily responsible for flow-mediated vasodilatation (FMD). We investigated the incidence of pulmonary edema in liver transplant patients and its correlation with FMD.

METHODS

We prospectively evaluated traditional risk factors, Doppler echocardiographic findings, derived hemodynamic data, and brachial artery nitroglycerin-induced vasodilatation (NTD) and FMD within 1 week prior to liver transplantation in 54 consecutive liver transplant patients with cirrhosis. Post-transplantation chest roentgenography was performed daily. In-hospital outcomes, transfusion volume of blood components, and hemodynamic data during surgery and at the intensive care unit were analyzed.

RESULTS

Twenty-nine patients (53.7%) developed radiological pulmonary edema within 1 week of transplantation. Diffuse-type interstitial and alveolar pulmonary edema constituted 13 cases (24.1%). Patients with pulmonary edema had higher pretransplantation Child-Turcotte-Pugh scores (p = 0.01), cardiac output (p = 0.03), FMD (p < 0.01), NTD (p = 0.01), and FMD/NTD ratio (p = 0.02). Although the total volume of intravenous fluid transfused was higher in the pulmonary edema group, the net fluid retention during surgery was statistically insignificant. The lengths of intensive care unit stay and hospitalization, as well as mortality rates, were not different in these groups.

CONCLUSIONS

The high incidence of pulmonary edema after living donor liver transplantation was associated with a high FMD and FMD/NTD ratio at pretransplantation. FMD is the only significant predictor associated with pulmonary edema. However, we observed no alteration in mortality rates.

KEY WORDS

Cirrhotic cardiomyopathy; Flow-mediated vasodilatation; Liver transplantation; Pulmonary edema.