Long-term cardiovascular risk in the orthotopic liver transplant population

New-Onset Atrial Fibrillation in Patients Undergoing Liver Transplantation: Retrospective Analysis of Risk Factors and Outcomes

OBJECTIVE

The authors aimed to identify predictors of new-onset postoperative atrial fibrillation (POAF) during the initial 90 days following liver transplantation, and to assess the association between POAF in-hospital and 1-year mortality.

DESIGN

A retrospective cohort study.

SETTING

At a university hospital between 2005 and 2017.

PATIENTS

Adults without a history of preoperative atrial fibrillation who underwent orthotopicliver transplantation.

MEASUREMENT AND MAIN RESULTS

The authors assessed the univariate association between new-onset of POAF in the postoperative period and each potential factor through a logistic regression model. Moreover, they explored predictors for POAF through stepwise selection. Finally, the authors assessed the relationship between POAF and in-hospital and 1-year mortality using logistic regression models, and whether the duration of atrial fibrillation was associated with in-hospital and 1-year mortality. Among 857 patients, 89 (10.4%) developed POAF. Using only preoperative variables, pulmonary hypertension, age, Model for End-Stage Liver Disease (MELD) score, and White race were identified as the most important predictors. Model discrimination was 0.75 (95% CI: 0.69-0.80), and incorporating intraoperative variables was 0.77 (95% CI: 0.72-0.82). In-hospital mortality was observed in 7.2% (6/83) of patients with new-onset of POAF, and in 2.8% (22/768) without, with confounder-adjusted odds ratio (OR) 1.00 (97.5% CI: 0.29,3.45; p = 0.996). One-year mortality was 22.4% (20/89) in patients who developed POAF and 8.3% (64/768) in patients who did not, confounder-adjusted OR 2.64 (97.5% CI: 1.35-5.16; p = 0.001). The duration of POAF did not affect long-term postoperative mortality.

CONCLUSION

Preoperative, mostly unmodifiable comorbidities are important risk factors for new-onset POAF after liver transplantation. The POAF was not associated with in-hospital mortality, but with increased 1-year mortality. Once developed, the duration of POAF did not affect long-term mortality after a liver transplant.

Prognostic value of coronary risk factors, exercise capacity and single photon emission computed tomography in liver transplantation candidates: A 5-year follow-up study

BACKGROUND

Although consensus-based guidelines support noninvasive stress testing prior to orthotopic liver transplantation (OLT), the optimal screening strategy for assessment of coronary artery disease in patients with end-stage liver disease (ESLD) is unclear. This study sought to determine the relative predictive value of coronary risk factors, functional capacity, and single photon emission computed tomography (SPECT) on major adverse cardiovascular events and all-cause mortality in liver transplantation candidates.

METHODS

Prior to listing for transplantation, 404 consecutive ESLD patients were referred to a University hospital for cardiovascular (CV) risk stratification. All subjects met at least one of the following criteria: inability to perform > 4 METs by history (62%), insulin-treated diabetes mellitus (53%), serum creatinine > 1.72 mg/dL (8%), history of MI, PCI or CABG (5%), stable angina (3%), cerebrovascular disease (1%), peripheral vascular disease (1%). Subjects underwent Technetium-99m SPECT with multislice coronary artery calcium scoring (CACS) using exercise treadmill or standard adenosine stress in those unable to achieve 85% maximal heart rate (Siemens Symbia T16). Abnormal perfusion was defined as a summed stress score (SSS) ≥ 4.

RESULTS

Of the 404 patients, 158 (age 59 ± 9 years; male 68%) subsequently underwent transplantation and were included in the primary analysis. Of those, 50 (32%) died after a mean duration follow-up of 5.4 years (maximal 10.9 years). Most deaths (78%) were attributed to noncardiovascular causes (malignancy, sepsis, renal failure). Of the 32 subjects with abnormal perfusion (20%), nine (6%) had a high-risk perfusion abnormality defined as a total perfusion defect size (PDS) ≥ 15% and/or an ischemic PDS ≥ 10%. Kaplan-Meier survival curves demonstrated abnormal perfusion was associated with increased CV mortality (generalized Wilcoxon, P = 0.014) but not all-cause death. Subjects with both abnormal perfusion and an inability to exercise > 4 METs had the lowest survival from all-cause death (P = 0.038). Abnormal perfusion was a strong independent predictor of CV death (adjusted HR 4.2; 95% CI 1.4 to 12.3; P = 0.019) and MACE (adjusted HR 7.7; 95% CI 1.4 to 42.4; P = 0.018) in a multivariate Cox regression model that included age, sex, diabetes, smoking and the ability to exercise > 4 METs. There was no association between CACS and the extent of perfusion abnormality, nor with outcomes.

CONCLUSIONS

Most deaths following OLT are noncardiovascular. Nonetheless, abnormal perfusion is prevalent in this high-risk population and a stronger predictor of cardiovascular morbidity and mortality than functional status. A combined assessment of functional status and myocardial perfusion identifies those at highest risk of all-cause death. (Exercise Capacity and Single Photon Emission Computed Tomography in Liver Transplantation Candidates [ExSPECT]; ClinicalTrials.gov Identifier: NCT03864497).

Understanding and managing cardiovascular outcomes in liver transplant recipients

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is a common cause of mortality after liver transplantation. The transplant community is focused on improving long-term survival. Understanding the prevalence of CVD in liver transplant recipients, precipitating factors as well as prevention and management strategies is essential to achieving this goal.

RECENT FINDINGS

CVD is the leading cause of death within the first year after transplant. Arrhythmia and heart failure are the most often cardiovascular morbidities in the first year after transplant which could be related to pretransplant diastolic dysfunction. Pretransplant diastolic dysfunction is reflective of presence of cirrhotic cardiomyopathy which is not as harmless as it was thought. Multiple cardiovascular risk prediction models have become available to aid management in liver transplant recipients.

SUMMARY

A comprehensive prevention and treatment strategy is critical to minimize cardiovascular morbidity and mortality after liver transplant. Weight management and metabolic syndrome control are cornerstones to any prevention and management strategy. Bariatric surgery is an underutilized tool in liver transplant recipients. Awareness of 'metabolic-friendly' immunosuppressive regimens should be sought. Strict adherence to the cardiology and endocrine society guidelines with regard to managing metabolic derangements post liver transplantation is instrumental for CVD prevention until transplant specific recommendations can be made.

Lactobacillus fermentum Improves Tacrolimus-Induced Hypertension by Restoring Vascular Redox State and Improving eNOS Coupling

SCOPE

The aim is to analyze whether the probiotic Lactobacillus fermentum CECT5716 (LC40) can prevent endothelial dysfunction and hypertension induced by tacrolimus in mice.

METHODS AND RESULTS

Tacrolimus increases systolic blood pressure (SBP) and impairs endothelium-dependent relaxation to acetylcholine and these effects are partially prevented by LC40. Endothelial dysfunction induced by tacrolimus is related to both increased nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) and uncoupled endothelial nitric oxide synthase (eNOS)-driven superoxide production and Rho-kinase-mediated eNOS inhibition. LC40 treatment prevents all the aortic changes induced by tacrolimus. LC40 restores the imbalance between T-helper 17 (Th17)/regulatory T (Treg) cells induced by tacrolimus in mesenteric lymph nodes and the spleen. Tacrolimus-induced gut dysbiosis, that is, it decreases microbial diversity, increases the Firmicutes/Bacteroidetes (F/B) ratio and decreases acetate- and butyrate-producing bacteria, and these effects are prevented by LC40. Fecal microbiota transplantation (FMT) from LC40-treated mice to control mice prevents the increase in SBP and the impaired relaxation to acetylcholine induced by tacrolimus.

CONCLUSION

LC40 treatment prevents hypertension and endothelial dysfunction induced by tacrolimus by inhibiting gut dysbiosis. These effects are associated with a reduction in vascular oxidative stress, mainly through NOX2 downregulation and prevention of eNOS uncoupling, and inflammation possibly because of decreased Th17 and increased Treg cells polarization in mesenteric lymph nodes.

Impact of immunosuppressive treatment on the cardiovascular system in patients after hand transplantation

BACKGROUND

Cardiovascular disease is a major cause of mortality in solid organ allograft recipients. Hand transplantation is not a lifesaving procedure, thus the effect of long-term immunosuppression on the cardiovascular system in these patients should be monitored. The aim of this study was to evaluate the morphology and function of heart and blood vessels in patients after hand transplantation.

METHODS

The study included 5 patients at ages 32 to 58 years, mean 39 years, who underwent hand transplantation between 2006 and 2010. Immunosuppressive treatment included basiliximab in induction and tacrolimus, mycophenolate mofetil, and prednisone. Cardiac status was assessed by echocardiography (according to the American Society of Echocardiography) and cardiac biomarkers. Blood vessels were estimated by carotid intima-media thickness, pulse wave velocity, and brachial artery flow-mediated dilatation (FMD). The examinations were performed at 28 to 79 (mean 43) months after transplantation.

RESULTS

Cardiovascular risk factors were observed in all patients after transplantation: 2 had insulin-dependent diabetes, 3 developed dyslipidemia and hypertension, 2 had chronic kidney disease stage 3. Concentric left ventricular hypertrophy was found in 1 and ventricular concentric remodeling in 4 patients. Impaired diastolic function (E/e' > 8) was observed in 2 patients. The index volume of the left atrium was higher in all patients. The cardiac biomarkers N-terminal pro-brain natriuretic peptide, C-reactive protein, and troponins were within normal range. Carotid intima-media thickness was higher in 1 patient and normal in 4 patients. Arterial stiffness measured by pulse wave velocity was not increased in all patients. Native brachial artery FMD response, an index of endothelium-dependent function, was abnormal in 2 patients, but in the transplanted extremity FMD was abnormal in 4 patients.

CONCLUSIONS

Pathologic changes in cardiac structures were found in all patients, but the arterial wall changes and endothelial dysfunction were observed in some patients. Patients after hand transplantation are at higher risk for cardiovascular disease.

Myocardial perfusion imaging is an effective screening test for coronary artery disease in liver transplant candidates

A reliable screening test for coronary artery disease (CAD) in liver transplant (LT) candidates with end-stage liver disease is essential because a high percentage of perioperative mortality and morbidity is CAD-related. In this study, the effectiveness of myocardial perfusion imaging (MPI) for identification of significant CAD in LT candidates was evaluated. Records of 244 patients meeting criteria for MPI were evaluated: 74 met inclusion criteria; 40 had a positive MPI and cardiology follow-up; 27 had a negative MPI and underwent LT; and seven had a negative MPI and then had coronary angiography or a significant cardiac event. A selective MPI interpretation strategy was established where MPI-positive patients were divided into high, intermediate, and low CAD risk groups. The overall incidence of CAD in this study population was 5.1% and our strategy resulted in PPV 20%, NPV 94%, sensitivity 80%, and specificity 50% for categorizing CAD risk. When applied only to the subset of patients categorized as high CAD risk, the strategy was more effective, with PPV 67%, NPV 97%, sensitivity 80%, and specificity 94%. We determined that renal dysfunction was an independent predictive factor for CAD (p < 0.0001, odds ratio = 8.1), and grades of coronary occlusion correlated significantly with chronic renal dysfunction (p = 0.0079).

Update in liver transplantation

PURPOSE OF REVIEW

Successful transplant outcomes require optimal patient selection and timing. This review will update clinicians with current status and challenges in liver transplantation. Currently, the major limitation facing liver transplant centers is the shortage of organs. The limited availability of organs has led to long waiting periods for liver transplantation and consequently many patients become seriously ill or die while on the waiting list.

RECENT FINDINGS

This has major implications in the selection of patients, as well as the timing of transplant, for optimal use of these scarce organs. Indications and contraindications have changed slightly over the years and will be reviewed in this article.

SUMMARY

Timing for transplantation has changed more dramatically in the recent years because major changes to organ allocation systems have been undertaken to provide clinicians with a better way to prioritize patients for liver transplant.

Coronary multidetector computed tomographic angiography to evaluate coronary artery disease in liver transplant candidates: methods, feasibility and initial experience

AIMS

In patients undergoing orthotopic liver transplantation (OLT), coronary artery disease (CAD), obstructive and nonobstructive, is associated with high morbidity and mortality. In OLT candidates, stress testing for detecting ischemia is often inaccurate, and this patient population often has relative contraindications for cardiac catheterization. The objective of this study was to describe the methods, assess the feasibility and determine the extent and severity of CAD in OLT candidates without a prior history of CAD using coronary multidetector computer tomographic angiography (MDCTA).

METHODS

Sixty-five OLT candidates without known CAD underwent coronary MDCTA with dual source cardiac computed tomography (Siemens Definition). Coronary arteries were divided into 17 segments based on American Heart Association guidelines and evaluated independently by two blinded reviewers. Image quality of coronary MDCTA was assessed on a four-point Likert scale (0 = poor, 1 = fair, 2 = good, and 3 = excellent). Atherosclerotic lesions were evaluated for severity [mild (0-50%), moderate (51-70%), and severe (71-100%)], morphology, extent, location and consistency.

RESULTS

Image quality was graded as good or excellent in 73.8%. In this cohort of OLT candidates without known CAD, 9% had normal coronary arteries, 58% had mild CAD and 34% had moderate to severe CAD. Plaque severity and burden scores were high.

CONCLUSION

The prevalence of asymptomatic CAD is high in OLT candidates. Coronary MDCTA is feasible in OLT candidates and appears to be a useful technique to diagnose occult CAD in this patient population.

Adult liver transplantation in the USA

PURPOSE OF REVIEW

To provide the nontransplant clinician with a basic understanding of the liver transplant process.

RECENT FINDINGS

Since its inception, the technique of liver transplantation and patient management has evolved considerably. We present an up-to-date overview of the evaluation of the transplant recipient and the listing and timing of transplant. We conclude with a brief summary of long-term complications, which should be considered when caring for the posttransplant patient.

SUMMARY

Liver transplantation is the only definitive treatment option for patients dying of liver failure. The growing population of patients with liver disease means that more transplants will be performed. As these patients now live longer lives, it is crucial that clinicians have a basic understanding of the process and outcomes.

Coronary artery disease in orthotopic liver transplantation: pretransplant assessment and management

The prevalence of coronary artery disease in end-stage liver disease is only now being recognized. Liver transplant patients are a high risk subgroup for coronary artery disease, even if asymptomatic. Coronary artery disease is a predictor of poor outcomes; therefore, identification of those at risk must be a key clinical priority. However, risk assessment is particularly difficult as many of the available diagnostic tools have either proven to be unhelpful or remain to be validated. Risk factor profiling has been unable to identify those at risk and commonly underestimates risk. The high negative predictive value of Dobutamine stress echo, when target heart rates are achieved, allows it to be used to identify a low risk group. For all other patients, proceeding to invasive coronary angiography is often necessary, and the risks of the procedure can be reduced by a transradial approach. Pharmacological reduction of the consequences of coronary artery disease can be limited by the underlying liver disease. Revascularization pre-transplantation is recommended in international guidelines but has demonstrated little evidence of benefit. Surgical revascularization carries an increased risk in these patients and is commonly performed pre-transplantation, although combined liver and cardiac surgery has been described. Percutaneous coronary intervention is increasingly used with patients requiring anti-platelet medication for up to one year after intervention. We present a review of all these issues and the evidence for assessing and managing these high-risk patients.

Cardiovascular risk profile of patients with acute liver failure after liver transplantation when compared with the general population

BACKGROUND

As opposed to most solid-organ transplant recipients, patients with acute liver failure exhibit a pretransplant health status more comparable with the general population, and any posttransplant cardiovascular risk excess should thus be more attributable to transplantation-related factors alone.

METHODS

This study compared the cardiovascular risk of 77 consecutive patients with acute liver failure at 5 years after liver transplantation with that of the general population using age, sex, and residence area-standardized prevalence ratios (SPR).

RESULTS

At least one cardiovascular risk factor developed in 92% of patients. Treated hypertension, observed in 71% of patients at 5 years, was more common among patients than controls (SPR, 2.73; 95% confidence interval [CI], 2.06-3.55), whereas the 61% prevalence of dyslipidemia and 3% prevalence of impaired fasting glucose were significantly less frequent among patients (SPR, 0.69; 95% CI, 0.51-0.92 and SPR, 0.29; 95% CI, 0.04-1.00). The 5-year prevalence of diabetes (10%), overweight (32%), and obesity (13%) deviated nonsignificantly from controls (SPR 1.90, 0.85, and 0.58). Antibody therapy associated with a 1.49-fold increase in the risk of hypertension (95% CI, 1.15-1.94) and a 6.43-fold increase in the risk of diabetes (95% CI, 1.18-34.9). Immunosuppression-type, steroids, acute rejection, retransplantation, or graft steatosis revealed nonsignificant risk alterations.

CONCLUSIONS

Liver transplantation and associated immunosuppression evidently cause hypertension, and possibly elicit diabetes in susceptible individuals. Conversely, the often reported transplantation-associated increased burden of overweight/obesity and dyslipidemia might relate mostly to other factors.

Renal function and cardiovascular risk profile after conversion from ciclosporin to tacrolimus: prospective study in 80 liver transplant recipients

BACKGROUND

Increased risk of cardiovascular and cerebrovascular disease in liver transplant recipients results in particular from the side effects of calcineurin inhibitor-based immunosuppressive therapy. Several studies have demonstrated a more favourable outcome for patients receiving tacrolimus (TAC) as compared with ciclosporin (CS).

AIM

To investigate the effects of conversion from CS to TAC on cardiovascular risk factors and renal function in liver transplant recipients.

METHODS

In a prospective study, all except two patients had chronic kidney disease stages 2-4 (n = 80), according to estimated glomerular filtration rate using the abbreviated Modification of Diet in Renal Disease equation.

RESULTS

Conversion was accompanied with a mean decrease of total cholesterol from 194.6 +/- 54.0 mg/dL to 175.8 +/- 44.2 mg/dL (P < 0.001), low density lipoprotein cholesterol from 106.7 +/- 39.2 mg/dL to 90.9 +/- 28.6 mg/dL (P < 0.001) and mean arterial blood pressure values from 102.2 +/- 13.2 mm Hg to 95.9 +/- 11.7 mm Hg (P < 0.001). Renal function remained stable. No cases of de novo diabetes mellitus were identified. The Framingham risk score was significantly reduced from 5.2 +/- 4.4 at baseline to 4.4 +/- 5.3 after 12 months (P = 0.006).

CONCLUSIONS

Conversion from CS to TAC has been shown to improve the cardiovascular risk profile and may retard further decline of renal function after liver transplantation.

Preoperative dobutamine stress echocardiographic findings and subsequent short-term adverse cardiac events after orthotopic liver transplantation

Cardiovascular (CV) complications are the leading cause of non-graft-related death in orthotopic liver transplant (OLT) patients. Pretransplant cardiac evaluation using dobutamine stress echocardiography (DSE) is commonly utilized for risk stratification of OLT candidates. To determine if clinical and echocardiographic variables identify patients with increased CV risk, we performed a retrospective chart review of all 284 patients that underwent OLT at our institution between June 1999 and August 2005. Of these patients, 157 had a DSE prior to their OLT. Serious adverse CV events occurring during surgery and up to 4 months post-transplantation were defined as cardiac-related death, myocardial infarction (MI), new heart failure, or asystole or unstable ventricular arrhythmia requiring acute treatment. Sixteen of 157 patients (10%) had an adverse CV event with 2 deaths. These included ventricular tachycardia (n = 8), asystole (n = 2), MI (n = 5), and new heart failure (n = 1). Nine of the 16 CV events occurred at the time of surgery (including both deaths), 5 occurred postoperatively, and 3 occurred after hospital discharge. Variables that correlated with increased CV events were inability during DSE to achieve >82% of the maximum predicted heart rate (22% versus 6%, P = 0.01), a peak rate pressure product during DSE of <16,333 (17% versus 5%, P = 0.02), and a Model for End-Stage Liver Disease (MELD) score of >24 at the time of OLT. A multivariate model calculated from the DSE maximum achieved heart rate (MAHR) and MELD score (result = 3.78 + 0.07 MELD - 0.05 MAHR) identified a 47% risk for a value > 0 versus a 6% risk for a value < 0 (P < 0.001). In conclusion, the maximum heart rate achieved during DSE together with the MELD score may be a predictor of adverse CV events up to 4 months post-OLT. A large prospective study is needed to more decisively support this conclusion.

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

Long-term follow-up studies on the impact of vascular events (VE) and risk factors of liver transplant recipients are scarce. In this study, 311 recipients of a first isolated liver transplant who survived at least 1 year were followed up from 1979 to 2002. The median follow-up duration was 6.2 (range1-22.7) years. Overall median survival was 18.7 [95% confidence interval (CI): 15.5-20.1] years and this was significantly lower compared with age- and sex-matched controls. Eleven (21%) of the patients had a vascular cause of death and VE were the third cause of death. VE occurred later compared with other causes of death (mean 10.3 years vs. 4.5 years, P < 0.0001, 95% CI: 2.7-8.9). Systolic hypertension, systolic blood pressure, smoking, renal failure, age, hypertriglyceridemia, serum total cholesterol levels and hypercholesterolemia at the 1-year follow-up visit were associated with the occurrence of VE, but renal failure and age at 1 year after transplantation were the only independent risk factors for vascular death (hazard ratio 0.06, 95% CI: 0.01-0.41 and hazard ratio 1.17, 95% CI: 1.02-1.34, respectively). Finally, it was shown that the adequate treatment of hypertension was associated with a significant reduced risk of vascular death. Therefore, vascular risk factors should be treated aggressively to prevent VE in the long term.