Sudden cardiac death following liver transplantation: Incidence, trends and risk predictors

Deep Learning-Based Prediction Modeling of Major Adverse Cardiovascular Events After Liver Transplantation

Objective

To validate deep learning models' ability to predict post-transplantation major adverse cardiovascular events (MACE) in patients undergoing liver transplantation (LT).

Patients and Methods

We used data from Optum's de-identified Clinformatics Data Mart Database to identify liver transplant recipients between January 2007 and March 2020. To predict post-transplantation MACE risk, we considered patients' demographics characteristics, diagnoses, medications, and procedural data recorded back to 3 years before the LT procedure date (index date). MACE is predicted using the bidirectional gated recurrent units (BiGRU) deep learning model in different prediction interval lengths up to 5 years after the index date. In total, 18,304 liver transplant recipients (mean age, 57.4 years [SD, 12.76]; 7158 [39.1%] women) were used to develop and test the deep learning model's performance against other baseline machine learning models. Models were optimized using 5-fold cross-validation on 80% of the cohort, and model performance was evaluated on the remaining 20% using the area under the receiver operating characteristic curve (AUC-ROC) and the area under the precision-recall curve (AUC-PR).

Results

Using different prediction intervals after the index date, the top-performing model was the deep learning model, BiGRU, and achieved an AUC-ROC of 0.841 (95% CI, 0.822-0.862) and AUC-PR of 0.578 (95% CI, 0.537-0.621) for a 30-day prediction interval after LT.

Conclusion

Using longitudinal claims data, deep learning models can efficiently predict MACE after LT, assisting clinicians in identifying high-risk candidates for further risk stratification or other management strategies to improve transplant outcomes based on important features identified by the model.

Enhancing pre-transplant cardiac assessment: Validation and utility of the CAD-LT score with CCTA in liver transplant candidates

BACKGROUND

Coronary computed tomography angiography (CCTA) is increasingly being used in the preoperative workup for liver transplantation (LT). We sought to assess the utility of integrating CCTA with the novel CAD-LT (Coronary Artery Disease in Liver Transplantation) score and its impact on reducing the need for invasive coronary angiography prior to LT.

METHODS

We conducted a retrospective cohort study of consecutive patients (age ≥ 18 years) who underwent CCTA for LT workup between 2011 and 2018 at the Victorian Liver Transplant Unit, Melbourne, Australia. CAD-LT scores, a traditional risk factor-based criteria, were calculated, and patients stratified as low-, intermediate- or high-risk.

RESULTS

Overall, 229 patients underwent CCTA. The mean age was 66 ± 5 years (82% male) with a modest-to-high risk factor burden (diabetes, 53%; hypertension, 46%; current or former smoker, 62%). The mean CAD-LT score of our cohort was 12.4 ± 4.0. No patients were classified as low-risk, 49 patients (21.4%) were deemed intermediate-risk and 180 patients (78.6%) were deemed high-risk. A high CAD-LT score (≥ 9) showed high sensitivity (95.3% [95% CI 86-98%]) and modest specificity (27.8% [95% CI 21-35%]) for the detection of obstructive coronary artery disease on CCTA, with a negative predictive value of 94%. Following multidisciplinary discussions, only 41 patients (18%) of patients proceeded to ICA of which 27% received percutaneous coronary intervention.

CONCLUSIONS

The use of CCTA in patients deemed intermediate- to high-risk by the CAD-LT score has the potential to reduce the need for invasive coronary angiography in patients undergoing LT workup.

Impact of Pretransplant Diabetes on Outcomes After Liver Transplantation: An Updated Meta-analysis With Systematic Review

BACKGROUND

Preliver transplant diabetes mellitus (pre-LT DM) is a common comorbidity in LT recipients associated with poorer post-transplant survival. However, its relationship with other important outcomes, including cardiovascular and renal outcomes, remains unclear. This meta-analysis aims to provide an updated analysis of the impact of pre-LT DM on key post-LT outcomes.

METHODS

A search was conducted in Medline and Embase databases for articles comparing the post-transplant outcomes between patients with and without pre-LT DM. Pairwise analysis using random effects with hazard ratios (HRs) was used to assess the longitudinal post-LT impacts of pre-LT DM. In the absence of HR, pooled odds ratios analysis was conducted for secondary outcomes.

RESULTS

Forty-two studies involving 77,615 LT recipients were included in this analysis. The pooled prevalence of pre-LT DM amongst LT recipients was 24.79%. Pre-LT DM was associated with significantly lower overall survival (HR, 0.65; 95% confidence interval, 0.52-0.81; P <0.01) and significantly increased cardiovascular disease-related mortality (HR, 1.78; 95% confidence interval, 1.11-2.85; P =0.03). Meta-regression of other patient characteristics identified Asian ethnicity and hypertension to be significant predictors of worse overall survival, whereas African-American ethnicity was associated with significantly improved overall survival in patients with pre-LT DM. Further analysis of secondary outcomes revealed pre-LT DM to be a significant predictor of post-LT cardiovascular events and end-stage renal disease.

CONCLUSIONS

The present study illustrates the impact of pre-LT DM on post-LT survival, and cardiovascular and renal outcomes and provides a sound basis for revision of preoperative management of pre-LT DM.

Atherosclerosis on CT coronary angiography and the risk of long-term cardiovascular events after liver transplantation

Computed tomography coronary angiography (CTCA) is increasingly utilized for preoperative risk stratification before liver transplantation (LT). We sought to assess the predictors of advanced atherosclerosis on CTCA using the recently developed Coronary Artery Disease-Reporting and Data System (CAD-RADS) score and its impact on the prediction of long-term major adverse cardiovascular events (MACE) following LT. We conducted a retrospective cohort study of consecutive patients who underwent CTCA for LT work-up between 2011 and 2018. Advanced atherosclerosis was defined as coronary artery calcium scores > 400 or CAD-RADS score ≥ 3 (≥50% coronary artery stenosis). MACE was defined as myocardial infarction, heart failure, stroke, or resuscitated cardiac arrest. Overall, 229 patients underwent CTCA (mean age 66 ± 5 y, 82% male). Of these, 157 (68.5%) proceeded with LT. The leading etiology of cirrhosis was hepatitis (47%), and 53% of patients had diabetes before transplant. On adjusted analysis, male sex (OR 4.6, 95% CI 1.5-13.8, p = 0.006), diabetes (OR 2.2, 95% CI 1.2-4.2, p = 0.01) and dyslipidemia (OR 3.1, 95% CI 1.3-6.9, p = 0.005) were predictors of advanced atherosclerosis on CTCA. Thirty-two patients (20%) experienced MACE. At a median follow-up of 4 years, CAD-RADS ≥ 3, but not coronary artery calcium scores, was associated with a heightened risk of MACE (HR 5.8, 95% CI 1.6-20.6, p = 0.006). Based on CTCA results, 71 patients (31%) commenced statin therapy which was associated with a lower risk of all-cause mortality (HR 0.48, 95% CI 0.24-0.97, p = 0.04). The standardized CAD-RADS classification on CTCA predicted the occurrence of cardiovascular outcomes following LT, with a potential to increase the utilization of preventive cardiovascular therapies.

Evolution of pretransplant cardiac risk factor burden and major adverse cardiovascular events in liver transplant recipients over time

Major adverse cardiovascular events (MACEs) are the leading cause of early (<1 y) complications after liver transplantation (LT). NASH, the leading indication for waitlisting for LT, is associated with high cardiac risk factor burden. The contemporary prevalence and temporal trends in pretransplant cardiac risk factor burden and post-LT MACE among LT recipients (LTRs) with and without NASH are unknown. The aim of this study was to evaluate (1) the evolution of post-LT cardiac risk factors in LTRs over time and (2) post-LT MACE over time, stratified by NASH status. This is a retrospective cohort of 1775 adult LTRs at a single transplant center (2003-2020). MACE was defined as death or hospitalization from myocardial infarction, revascularization, stroke, heart failure during the first post-LT year. Between 2003 and 2020, there was a significant increase in pre-LT NASH ( ptrend <0.05). There was also a significant increase in pre-LT obesity, atherosclerotic cardiovascular (CV) disease, and older age (≥65 y old) ( ptrend <0.05 for all). There was no significant change in the proportion of LTRs with diabetes, chronic kidney disease, or heart failure. Unexpectedly, there were no changes in the rate of post-LT MACE over the study period (-0.1% per year, ptrend =0.44). The lack of change in MACE despite an increase in CV risk factor prevalence may reflect advancement in the identification and management of CV risk factors in LTRs. With projected continued increase in cardiac risk burden and the proportion of patients transplanted for NASH, it is critical for LT programs to develop and implement quality improvement efforts to optimize CV care in LTRs.

Evaluation of recipients with significant comorbidity - Patients with cardiovascular disease

Liver transplant(ation) (LT) is the most effective treatment for patients with decompensated liver disease. The increasing prevalence of obesity and type 2 diabetes and the growing number of patients with non-alcoholic fatty liver disease being evaluated for LT, have resulted in a greater proportion of LT candidates presenting with a higher risk of cardiovascular disease. As cardiovascular disease is a major cause of morbidity and mortality after LT, a thorough cardiovascular evaluation pre-LT is crucial. In this review, we discuss the latest evidence on the cardiovascular evaluation of LT candidates and we focus on the most prevalent conditions, namely ischaemic heart disease, atrial fibrillation and other arrhythmias, valvular heart disease, and cardiomyopathies. LT candidates undergo an electrocardiogram, a resting transthoracic echocardiography and an assessment of their cardiopulmonary functional ability as part of their standardised pre-LT work-up. Further diagnostic work-up is undertaken based on the results of the baseline evaluation and may include a coronary computed tomography angiography in patients with cardiovascular risk factors. The evaluation of potential LT candidates for cardiovascular disease requires a multidisciplinary approach, with input from anaesthetists, cardiologists, hepatologists and transplant surgeons.

Metabolic syndrome, hepatic fibrosis, and steatosis diagnosed by liver stiffness measurement and controlled attenuation parameter after liver transplantation: the impact on long-term survival

BACKGROUND

Liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) are used for diagnosis of liver fibrosis and steatosis. This study aimed to noninvasively evaluate hepatic steatosis and fibrosis in liver transplant recipients using CAP and LSM and the impact on survival of patients.

METHODS

In a prospective study, adult liver transplant recipients were included. CAP and LSM obtained during transient elastography (TE) were used for assessment of hepatic steatosis and fibrosis. Patients were followed during 4 years for mortality as the main outcome after liver transplantation.

RESULTS

From 296 patients, 24.7% and 25% of liver transplant recipients had liver steatosis and fibrosis in CAP and LSM, respectively. In multivariable Cox regression analysis, etiology of liver disease (NASH versus non-NASH) (HR: 3.125; 95% CI: 1.594-6.134; p = 0.001), and post-transplant diabetes mellitus (PTDM) (HR: 2.617; 95% CI: 1.396-4.926; p = 0.003) were associated with hepatic steatosis after liver transplantation.  In multivariable Cox regression analysis, liver fibrosis was an independent predictor of mortality after liver transplantation (HR: 4.926; 95%CI: 1.779-13.513; p = 0.002).

CONCLUSION

CAP and LS measurement during TE are useful methods for diagnosis of hepatic steatosis and fibrosis in liver transplant recipients. LS measurement might predict long-term survival of patients.

Impact of cardiac dysfunction on morbidity and mortality in liver transplant candidates

The prognostic role of cardiac dysfunction in cirrhotic patients is increasingly recognised. We studied its impact on morbidity and mortality before and after liver transplantation (LT) including development of post-transplant cardiovascular disease (CVD). In this retrospective study, cirrhotic patients who underwent LT assessment from January 2010 to December 2020 were reviewed. Demographics, cardiac investigations and clinical course were analysed to identify prevalence of cardiac dysfunction and its role in LT outcomes. Survival analysis was performed using Cox proportional hazard regression modelling, with LT as a time-varying covariate and as an interaction variable with cardiac dysfunction. 308 patients (70% male) were studied. The median (interquartile range) age at LT assessment was 56 (12) years. Cardiac dysfunction was found in 178 (58%) patients (diastolic, 169; systolic, 26; both, 17) and was significantly associated with hepatorenal syndrome/acute kidney injury and peri- and post-transplant morbidity (adjusted odds ratio [aOR] 1.94, 95%CI 1.06-3.52, p < 0.001; aOR 2.01, 95%CI 1.06-3.82, p = 0.033; aOR 1.9, 95%CI 1.01-3.65, p = 0.023, respectively). Cardiac dysfunction was not associated with mortality before (adjusted hazard ratio [aHR] 1.01, 95% CI 0.99-1.01) or after LT (aHR 0.74, 95% CI 0.4-1.05. Post-transplant CVD (61% cardiac failure) occurred in 36 patients and there was no significant association with cardiac dysfunction (p = 0.11). Cardiac dysfunction was common in LT candidates and was significantly associated with morbidity before and after LT. Studies on the role of advanced echocardiographic parameters to improve diagnosis of cardiac dysfunction and optimise LT outcomes are needed. This article is protected by copyright. All rights reserved.

Adverse effects of immunosuppression after liver transplantation

After solid organ transplantation the cornerstone of immunosuppression is based on calcineurin inhibitors (CNIs), mostly tacrolimus. However, CNIs have a very narrow therapeutic window. The most important and serious side-effects of CNIs are nephrotoxicity, high blood pressure, post-transplant diabetes mellitus (PTMD), i.e., new-onset diabetes after transplantation (NODAT), dyslipidemia, and modification to the cardiovascular-risk profile. In this review, we will focus on tacrolimus-related toxicities in the setting of liver transplantation.

Evidence-Based Analysis of the Emergency Temporary Cardiac Pacing (Electrical Stimulation from Metal Wire Electrode)

The patient's Cr (creatinine), BUN (blood urea nitrogen), HBG (hemoglobin), VT (ventricular tachycardia), pacing frequency, puncture point, emergency to permanent pacing time, pacing current (mA), pacing threshold current (mA), and admission diagnosis data were collected. The data were subjected to frequency statistics, curve regression analysis, PLS regression analysis, adjustment analysis, chi-square test, ridge regression analysis, discriminant analysis, negative binomial regression analysis, Poisson regression analysis, and stepwise regression analysis. Some findings include the following: (1) Cr has a significant positive effect on HBG, and BUN has a significant negative effect on HBG. (2) VT has a negative correlation with age and a positive correlation with CK-MB and CK (creatinine kinase). (3) Myocarditis has a negative correlation with age and a significant positive correlation with CTnI (cardiac troponin I). (4) AST (aspartate transaminase) and ALT (alanine aminotransferase) have a significant positive impact on DDI (D-dimer), while CTnI has a significant negative impact on DDI. MYO (myoglobin) has no impact relationship to DDI. (5) ALT has a significant positive relationship with APTT (partial thromboplastin time). (6) Alb (albumin) and TBIL (total bilirubin) have a significant positive effect on PLT (platelet) count, while pro-BNP (B-type natriuretic peptide) and MYO have a significant negative effect on PLT. (7) CK has a significant positive effect on INR (international normalized ratio). (8) The relationship between sinus node dysfunction and VT significantly affect the pacing frequency (beats/minute). For third-degree atrioventricular block, different samples of sinus node dysfunction showed significant differences. (9) There is a significant positive correlation between pacing current (mA) and pacing threshold current (mA). (10) There was a significant positive correlation between perceived voltage (mV) and the time from emergency to permanent pacing. Admission diagnosis has a significant positive impact on the time from emergency to permanent pacing. The change (increase) in time from emergency to permanent pacing was 1.137-fold when an additional condition was diagnosed on admission.

Combined B-type Natriuretic Peptide as strong predictor of short-term mortality in patients after Liver Transplantation

Background: B-type natriuretic peptide (BNP) is a well-known predictor for prognosis in patients with cardiac and renal diseases. However, there is a lack of studies in patients with advanced hepatic disease, especially patients who underwent liver transplantation (LT). We evaluated whether BNP could predict the prognosis of patients who underwent LT. Material and Methods: The data from a total of 187 patients who underwent LT were collected retrospectively. The serum levels of BNP were acquired at four time points, the pre-anhepatic (T1), anhepatic (T2), and neohepatic phases (T3), and on postoperative day 1 (T4). The patients were dichotomized into survival and non-survival groups for 1-month mortality after LT. Combined BNP (cBNP) was calculated based on conditional logistic regression analysis of pairwise serum BNP measurements at two time points, T2 and T4. The area under the receiver operating characteristic curve (AUROC) was analyzed to determine the diagnostic accuracy and cut-off value of the predictive models, including cBNP. Results: Fourteen patients (7.5 %) expired within one month after LT. The leading cause of death was sepsis (N = 9, 64.3 %). The MELD and MELD-Na scores had an acceptable predictive ability for 1-month mortality (AUROC = 0.714, and 0.690, respectively). The BNPs at each time point (T1 - T4) showed excellent predictive ability (AUROC = 0.864, 0.962, 0.913, and 0.963, respectively). The cBNP value had an outstanding predictive ability for 1-month mortality after LT (AUROC = 0.976). The optimal cutoff values for cBNP at T2 and T4 were 137 and 187, respectively. Conclusions: The cBNP model showed the improved predictive ability for mortality within 1-month of LT. It could help clinicians stratify mortality risk and be a useful biomarker in patients undergoing LT.