Vascular events after liver transplantation: a long-term follow-up study

Management of cardiac diseases in liver transplant recipients: Comprehensive review and multidisciplinary practice-based recommendations

Cardiac diseases are one of the most common causes of morbidity and mortality following liver transplantation (LT). Prior studies have shown that cardiac diseases affect close to one-third of liver transplant recipients (LTRs) long term and that their incidence has been on the rise. This rise is expected to continue as more patients with advanced age and/or non-alcoholic steatohepatitis undergo LT. In view of the increasing disease burden, a multidisciplinary initiative was developed to critically review the existing literature (between January 1, 1990 and March 17, 2021) surrounding epidemiology, risk assessment, and risk mitigation of coronary heart disease, arrhythmia, heart failure, and valvular heart disease and formulate practice-based recommendations accordingly. In this review, the expert panel emphasizes the importance of optimizing management of metabolic syndrome and its components in LTRs and highlights the cardioprotective potential for the newer diabetes medications (e.g., sodium glucose transporter-2 inhibitors) in this high-risk population. Tailoring the multidisciplinary management of cardiac diseases in LTRs to the cardiometabolic risk profile of the individual patient is critical. The review also outlines numerous knowledge gaps to pave the road for future research in this sphere with the ultimate goal of improving clinical outcomes.

Prospective assessment of subclinical cardiovascular damage and associated factors in liver transplant recipients

Cardiovascular (CV) disease plays a major role after liver transplantation (LT). This prospective study assessed subclinical CV damage after LT by measuring pulse wave velocity (PWV), intima-media thickness (IMT) and left-ventricular mass index (LVMI) and characterized associated risk factors. We included 112 patients with a median of 1.8 years after LT (q1-q3 0.9-9.2). Fifty-three percent (n = 59) of patients had ≥2 annual assessments (median follow-up 1.6 years, q1-q3 1.1-2.0), with a total of 195 assessments. We found increased PWV (indicating arteriosclerosis) in 16% (n = 17), elevated IMT in 5% (n = 5; indicating atherosclerosis) and increased LVMI in 25% (n = 24; indicating left-ventricular hypertrophy). A linear mixed model analysis using all 195 assessments revealed that higher age and systolic blood pressure (BP) were associated with higher PWV (β = 0.069, P < 0.001 and β = 0.022, P = 0.005) and higher IMT (β = 0.005, P < 0.001 and β = 0.001, P = 0.029), while higher body mass index was associated with higher IMT (β = 0.004, P = 0.023). Higher systolic BP (β = 0.200, P = 0.034), male sex (β = 8.847, P = 0.031) and lower glomerular filtration rate (β = -0.288, P < 0.001) were associated with higher LVMI. Our data highlight not only the rate of subclinical CV damage in LT patients, but also the impact of classical CV risk factors (such as BP and body mass index) which outweighed LT-related factors. These modifiable risk factors are suitable targets for interventions to reduce CV morbidity in LT patients.

Approach to the liver transplant early postoperative period: an institutional standpoint

The liver transplant program in our center started in 1992, and post-liver transplant patients are still admitted to the intensive care unit. For the intensive care physician, a learning curve started then, skills were acquired, and a specific practice was established. Throughout this time, several concepts changed, improving the care of these patients. The practical approach varies between liver transplant centers, according to local specificities. Hence, we wanted to present our routine practice to stimulate the debate between dedicated teams, which can allow the introduction of new ideas and potentially improve each local standard of care.

Incidence of and Risk Assessment for Adverse Cardiovascular Outcomes After Liver Transplantation: A Systematic Review

BACKGROUND

Cardiovascular events represent a major source of morbidity and mortality after liver transplantation and will likely increase given the aging population and nonalcoholic fatty liver disease as a leading indication for transplant. The optimal cardiovascular risk stratification approach in this evolving patient population remains unclear. The aims of this systematic review are to: (1) refine the definition, (2) characterize the incidence, and (3) identify risk factors for cardiovascular events post-liver transplantation. Additionally, we evaluated performance characteristics of different cardiac testing modalities.

METHODS

MEDLINE via PubMed, EMBASE, Web of Science, and Scopus were searched for studies published between 2002 and 2016 (model of end-stage liver disease era). Two authors independently reviewed articles to select eligible studies and performed data abstraction.

RESULTS

Twenty-nine studies representing 57 493 patients from 26 unique cohorts were included. Definitions of cardiovascular outcomes were highly inconsistent. Incidence rates were widely variable: 1% to 41% for outcomes of 6 months or shorter and 0% to 31% for outcomes longer than 6 months. Multivariate analyses demonstrated that older age and history of cardiac disease were the most consistent predictors of cardiovascular events posttransplant (significant in 8/23 and 7/22, studies, respectively). Predictive capacity of various cardiac imaging modalities was also discrepant.

CONCLUSIONS

The true incidence of cardiovascular outcomes post-liver transplant remains unknown in large part due to lack of consensus regarding outcome definition. Overall, poor data quality and gaps in knowledge limit the ability to clearly identify predictors of outcomes, but existing data support a more aggressive risk stratification protocol for patients of advanced age and/or with preexisting cardiac disease.

Deep Vein Thrombosis and Pulmonary Embolism in Liver Transplant Patients: Risks and Prevention

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are surgical complications estimated to occur in 5% to 10% of patients. There are limited data regarding DVT/PE in the early postoperative period in liver transplant patients. The aim of this study is to determine risk factors that influence the incidence of DVT/PE and the effectiveness of prophylaxis.

Abnormal hemostatic function one year after orthotopic liver transplantation can be fully attributed to endothelial cell activation

Background: The long-term risk of thrombotic and vascular complications is elevated in liver transplant recipients compared to the general population. Patients with cirrhosis are in a hypercoagulable status during and directly after orthotopic liver transplantation, but it is unclear whether this hypercoagulability persists over time.

Aim: We aimed to investigate the hemostatic status of liver transplant recipients one year after transplantation.

Methods: We prospectively collected blood samples of 15 patients with a functioning graft one year after orthotopic liver transplantation and compared the hemostatic status of these patients with that of 30 healthy individuals.

Results: Patients one year after liver transplantation had significantly elevated plasma levels of von Willebrand factor (VWF). Thrombin generation, as assessed by the endogenous thrombin potential, was decreased in patients, which was associated with increased plasma levels of the natural anticoagulants antithrombin and tissue factor pathway inhibitor.  Plasma fibrinolytic potential was significantly decreased in patients and correlated inversely with levels of plasminogen activator inhibitor-1.

Conclusion: One year after liver transplantation, liver graft recipients have a dysregulated hemostatic system characterised by elevation of plasma levels of endothelial-derived proteins. Increased levels of von Willebrand factor and decreased fibrinolytic potential may (in part) be responsible for the increased risk for vascular disease seen in liver transplant recipients.

Abnormal hemostatic function one year after orthotopic liver transplantation can be fully attributed to endothelial cell activation

BACKGROUND

The long-term risk of thrombotic and vascular complications is elevated in liver transplant recipients compared to the general population. Patients with cirrhosis are in a hypercoagulable status during and directly after orthotopic liver transplantation, but it is unclear whether this hypercoagulability persists over time.

AIM

We aimed to investigate the hemostatic status of liver transplant recipients one year after transplantation.

METHODS

We prospectively collected blood samples of 15 patients with a functioning graft one year after orthotopic liver transplantation and compared the hemostatic status of these patients with that of 30 healthy individuals.

RESULTS

Patients one year after liver transplantation had significantly elevated plasma levels of von Willebrand factor (VWF). Thrombin generation, as assessed by the endogenous thrombin potential, was decreased in patients, which was associated with increased plasma levels of the natural anticoagulants antithrombin and tissue factor pathway inhibitor.  Plasma fibrinolytic potential was significantly decreased in patients and correlated inversely with levels of plasminogen activator inhibitor-1.

CONCLUSION

One year after liver transplantation, liver graft recipients have a dysregulated hemostatic system characterised by elevation of plasma levels of endothelial-derived proteins. Increased levels of von Willebrand factor and decreased fibrinolytic potential may (in part) be responsible for the increased risk for vascular disease seen in liver transplant recipients.

Cardiac work-up protocol for liver transplant candidates: experience from a single liver transplant centre

BACKGROUND

Ischemic cardiac events can cause significant morbidity and mortality postliver transplantation; however, no validated protocols to screen patients before transplantation exist.

OBJECTIVES

To report the introduction of a noninvasive cardiac screening protocol used at the Liver Unit, University of Calgary (Calgary, Alberta); to determine whether the protocol decreases use of coronary angiograms; and to compare cardiac outcomes using the new protocol with an appropriately matched historical control group.

METHODS

A new cardiac screening protocol was introduced into the program in 2005, which uses perfusion scintigraphy to screen high-risk cardiac patients, reserving coronary angiograms for abnormal results. Transplanted patients screened using this protocol were compared with matched historical controls. Electronic charts were reviewed for cardiac outcomes intra- and postliver transplantation.

RESULTS

A total of 396 patients were screened between April 2005 and February 2009. Eighty-two were transplanted by February 2009 and included in the study. Eighty-one patients were successfully matched according to age, sex, cardiac history and presence of diabetes. Twelve of 82 (14.6%) and 11 of 81 (13.6%) in the study and control groups, respectively, underwent coronary angiograms (P=0.85). Coronary artery disease was found in six of 12 (50.0%) study patients and three of 11 (27.3%) control patients who underwent coronary angiography (P=0.27). The mean (± SD) length of the follow-up period was 1.87±0.91 years and 4.45±1.89 years in the study and control groups, respectively. One of 81 in the control group and zero of 82 in the study group experienced an acute coronary syndrome event postoperatively.

CONCLUSIONS

Coronary events are infrequent in liver transplant recipients. The described protocol is an effective method of coronary artery disease screening before liver transplant but does not reduce the number of cardiac investigations performed.