Coronary event rates in liver transplant recipients reflect the increased prevalence of cardiovascular risk-factors

Cardiovascular mortality following liver transplantation: predictors and temporal trends over 30 years

AIMS

There has been significant evolution in operative and post-transplant therapies following liver transplantation (LT). We sought to study their impact on cardiovascular (CV) mortality, particularly in the longer term.

METHODS AND RESULTS

A retrospective cohort study was conducted of all adult LTs in Australia and New Zealand across three 11-year eras from 1985 to assess prevalence, modes, and predictors of early (≤30 days) and late (>30 days) CV mortality. A total of 4265 patients were followed-up for 37 409 person-years. Overall, 1328 patients died, and CV mortality accounted for 228 (17.2%) deaths. Both early and late CV mortality fell significantly across the eras (P < 0.001). However, CV aetiologies were consistently the leading cause of early mortality and accounted for ∼40% of early deaths in the contemporary era. Cardiovascular deaths occurred significantly later than non-cardiac aetiologies (8.8 vs. 5.2 years, P < 0.001). On multivariable Cox regression, coronary artery disease [hazard ratio (HR) 4.6, 95% confidence interval (CI) 1.2-21.6; P = 0.04] and era of transplantation (HR 0.44; 95% CI 0.28-0.70; P = 0.01) were predictors of early CV mortality, while advancing age (HR 1.05, 95% CI 1.02-1.10; P = 0.005) was an independent predictors of late CV mortality. Most common modes of CV death were cardiac arrest, cerebrovascular events, and myocardial infarction.

CONCLUSION

Despite reductions in CV mortality post-LT over 30 years, they still account for a substantial proportion of early and late deaths. The late occurrence of CV deaths highlights the importance of longitudinal follow-up to study the efficacy of targeted risk-reduction strategies in this unique patient population.

Evaluating twenty-years of follow-up after orthotopic liver transplantation, best practice for donor-recipient matching: What can we learn from the past era?

AIM

To characterize major determinants of 20-year survival after liver transplantation (LT).

METHODS

This longitudinal single-institution study includes 313 consecutive patients who received a LT between 1988 and 1992. Pretransplant clinical characteristics and laboratory values were assessed and compared between 20-year survivors and non-survivors. Particular attention was paid to the Model for End-Stage Liver Disease (labMELD)-score and the Eurotransplant Donor Risk Index (ET-DRI) to unravel their impact on 20-year survival after LT.

RESULTS

Twenty-year survivors were significantly younger (44 vs 50 years, P = 0.001), more likely to be female (49% vs 36%, P = 0.03) and less likely to be obese at the time of LT (19% vs 32%, P = 0.011). Mean labMELD-score (P = 0.156), rate of high-urgency LT (P = 0.210), cold-ischemia time (P = 0.994), rate of retransplantation (P = 0.12) and average donor age (28 vs 33 years, P = 0.099) were not statistically different. The mean estimated glomerular filtration rate was higher among survivors (P = 0.007). ET-DRI > 1.4 (P = 0.020) and donor age ≥ 30 years (P < 0.022) had significant influence on 20-year survival. The overall survival was not significantly impacted by labMELD-score categories (P = 0.263).

CONCLUSION

LT offers excellent long-term results in case of optimal donor and recipient conditions. However, mainly due to the current organ shortage, these ideal circumstances are rarely given; thus algorithms for donor-recipient matching need to be refined, in order to enable a maximum benefit for the recipients of high quality as well as marginal organs.

Lipid profile and cardiovascular risk factors in pediatric liver transplant recipients

Cardiovascular diseases induce long-term morbidity and mortality of adult LT recipients. The aim of this retrospective study was to assess CVRF, lipid abnormalities, and atherosclerosis (appraised by c-IMT), more than 10 yr after pediatric LT. Thirty-one children who underwent LT between December 1990 and December 2000 were included. Median age at LT was 14 months (range 4-64), and median follow-up after LT was 11.9 yr (range 9.0-17.3). In our cohort, obesity (9.7%) and treated hypertension (9.7%) were rare. None of the patients was smoker or diabetic. High TC and TG were both observed in 6.5% of the patients. The mean c-IMT for male patients was 1.22 ± 1.55 and 1.58 ± 1.23 mm in female patients. Seven patients (22%) had a mean c-IMT above +2 s.d. Values below the 5th percentile were noted for LDL-cholesterol (58.1%), HDL-cholesterol (25.8%), apolipoprotein B (40%), and apolipoprotein A1 (20%). LDL-cholesterol and apolipoprotein B levels were significantly lower in patients treated by tacrolimus in comparison with CsA (p < 0.05). In conclusion, our results suggest that pediatric LT patients do not present significant CVRF; moreover, instead of hyperlipidemia, hypocholesterolemia (LDL-C) is frequent and immunosuppressive therapy is probably the cause.

Cardiovascular risk 10 years after liver transplant

OBJECTIVES

We sought to evaluate the frequency of cardiovascular risk factors in a cohort of patients 10 years after a liver transplant, and to assess their 10-year risk of fatal cardiovascular disease using Systematic COronary Risk Evaluation (SCORE) charts.

MATERIALS AND METHODS

Between January 1990 and June 1996, one hundred eighty-nine adults underwent a first liver transplant in our center. Fifty-nine patients (31%) died before reaching their tenth year, and 115 patients were available with complete clinical data at 10 years.

RESULTS

The main indications for liver transplant were alcoholic (38%) and viral cirrhosis (40%). The median age of patients was 56 (range, 29-73 y), 80% were men, 23% were obese, 16% were active smokers, 18% were diabetic, 40% had hypercholesterolemia, and 77% had hypertension. Before the tenth year after transplant, 6 deaths were because of cardiovascular diseases, which represents the third cause of late death (> 1 year after liver transplant). After liver transplant, 5% of the surviving patients underwent ischemic cardiovascular events during the first decade. At a 10-year assessment, the median estimated 10-year risk of fatal cardiovascular disease was 1% (range, 0%-9%) and 10% of the patients had a high risk (ie, SCORE ≥ 5%).

CONCLUSIONS

Our results suggest that the frequency of cardiovascular events is relatively low after a liver transplant, even if most of the patients had 1 or more cardiovascular risk factors. Nevertheless, clinicians should perform a similar evaluation 15 or 20 years after the liver transplant because cardiovascular risk exponentially increases with age.

Appraising cardiac dysfunction in liver transplantation: an ongoing challenge

End-stage liver disease (ESLD) is a multisystemic disease that adversely and mutually aggravates other organs such as the heart. Cardiac dysfunction in ESLD encompasses a spectrum of disease that could be aggravated, precipitated or be occurring hand-in-hand with coexisting aetiological factors precipitating cirrhosis. Additionally and more complexly, liver transplantation, the curative modality of ESLD, is responsible for additional intra- and postoperative short- and long-term cardiac morbidity. The phenotypic distinction of the different forms of cardiac dysfunction in ESLD albeit important prognostically and therapeutically is not allowed by the current societal recommendations, due to conceptual, and methodological limitations in the appraisal of cardiac function and structure in ESLD and in designing studies that are based on this appraisal. This review comprehensively discusses the spectrum of cardiac dysfunction in ESLD, discusses the limitations of the current appraisal of cardiac dysfunction in ESLD, and proposes a hypothetical approach for studying cardiac dysfunction in liver transplant candidates.

Cardiovascular complications after transplantation: treatment options in solid organ recipients

Premature cardiovascular disease is the commonest cause of death in solid organ transplant recipients, with coronary artery disease, sudden cardiac death and heart failure being highly prevalent. There are unique factors leading to CV disease in organ transplant recipients that include underlying comorbidities, and metabolic effects of immunosuppression. As a consequence management strategies developed in the general population may have limited benefit. In this review, we will focus on renal transplantation, where most research has been carried out and, despite incomplete understanding of the disease process, the incidence of cardiovascular disease appears to be falling.

Twenty-year longitudinal follow-up after orthotopic liver transplantation: a single-center experience of 313 consecutive cases

With excellent short-term survival in liver transplantation (LT), we now focus on long-term outcome and report the first European single-center 20-year survival data. Three hundred thirty-seven LT were performed in 313 patients (09/88-12/92). Impact on long-term outcome was studied and a comparison to life expectancy of matched normal population was performed. A detailed analysis of 20-years follow-up concerning overweight (HBMI), hypertension (HTN), diabetes (HGL), hyperlipidemia (HLIP) and moderately or severely impaired renal function (MIRF, SIRF) is presented. Patient and graft survival at 1, 10, 20 years were 88.4%, 72.7%, 52.5% and 83.7%, 64.7% and 46.6%, respectively. Excluding 1-year mortality, survival in the elderly LT recipients was similar to normal population. Primary indication (p < 0.001), age (p < 0.001), gender (p = 0.017), impaired renal function at 6 months (p < 0.001) and retransplantation (p = 0.034) had significant impact on patient survival. Recurrent disease (21.3%), infection (20.6%) and de novo malignancy (19.9%) were the most common causes of death. Prevalence of HTN (57.3-85.2%, p < 0.001), MIRF (41.8-55.2%, p = 0.01) and HBMI (33.2-45%, p = 0.014) increased throughout follow-up, while prevalence of HLIP (78.0-47.6%, p < 0.001) declined. LT has conquered many barriers to achieve these outstanding long-term results. However, much work is needed to combat recurrent disease and side effects of immunosuppression (IS).

Long-term outcome of 'long-term liver transplant survivors'

There are few studies focusing on long-term complications in liver transplant (LT) recipients. The aim of this study was to define the outcome of LT recipients having survived at least 10 years from LT. Of 323 adult LT done between 1991 and 1997, the 167(52%) alive >10 years post-LT (baseline time) formed the study population. Long-term outcome measures included the following: immunosuppression, metabolic complications [obesity, arterial hypertension (AH), diabetes, dislypidemia], cardiovascular events (CVE), chronic renal dysfunction-CRD, and de novo tumors. Median age at LT was 50 years. Most common indication was postnecrotic cirrhosis (89%), mostly because of HCV (46%). At study-baseline (10 years post-LT), 29% were obese and AH, diabetes, dislypidemia, and CRD were present in 75%, 30%, 42%, and 36%, respectively. In most cases, these complications were already present 1 year post-LT; less than one quarter developed them onward. The 6 year cumulative survival since baseline reached 84% (n = 24 deaths), with most deaths related to recurrent graft diseases (mostly HCV) followed by de novo tumors or CVE. 1, 3, 5 and 10 years cumulative rates of CVE and de novo tumors since baseline were 2%, 5%, 10% and 17%, and 1%, 3%, 6% and 13%, respectively. Chronic renal impairment was independently associated with survival and development of CVE since baseline. The medium-term survival of 'long-term survivors', i.e. patients alive 10 years after LT is good, but metabolic complications and CRD are common and continue to increase afterwards. Cardiovascular events and de novo tumors increase gradually over time and represent a major cause of late mortality.

Patients transplanted for nonalcoholic steatohepatitis are at increased risk for postoperative cardiovascular events

Nonalcoholic steatohepatitis (NASH) is an independent predictor of coronary artery disease (CAD). Our aim was to compare the incidence of cardiovascular (CV) events between patients transplanted for NASH and alcohol (ETOH)-induced cirrhosis. This is a retrospective cohort study (August 1993 to March 2010) of 242 patients (115 NASH and 127 ETOH) with ≥12 months follow-up after liver transplantation (LT). Those with hepatocellular carcinoma or coexisting liver diseases were excluded. Kaplan-Meier's and Cox's proportional hazard analyses were conducted to compare survival. Logistic regression was used to calculate the likelihood of CV events, defined as death from any cardiac cause, myocardial infarction, acute heart failure, cardiac arrest, arrhythmia, complete heart block, and/or stroke requiring hospitalization <1 year after LT. Patients in the NASH group were older (58.4 versus 53.3 years) and were more likely to be female (45% versus 18%; P < 0.001). They were more likely to be morbidly obese (32% versus 9%), have dyslipidemia (25% versus 6%), or have hypertension (53% versus 38%; P < 0.01). On multivariate analysis, NASH patients were more likely to have a CV event <1 year after LT, compared to ETOH patients, even after controlling for recipient age, sex, smoking status, pretransplant diabetes, CV disease, and the presence of metabolic syndrome (26% versus 8%; odds ratio = 4.12; 95% confidence interval = 1.91-8.90). The majority (70%) of events occurred in the perioperative period, and the occurrence of a CV event was associated with a 50% overall mortality. However, there were no differences in patient, graft, or CV mortality between groups.

CONCLUSIONS

CV complications are common after LT, and NASH patients are at increased risk independent of traditional cardiac risk factors, though this did not affect overall mortality.

Cumulative risk of cardiovascular events after orthotopic liver transplantation

As survival after orthotopic liver transplantation (OLT) improves, cardiovascular (CV) disease has emerged as the leading cause of non-graft-related deaths. The aims of our study were to determine the cumulative risk of CV events after OLT and to analyze predictive risk factors for those experiencing a CV event after OLT. We identified all adult patients who underwent OLT at our institution for end-stage liver disease between October 1996 and July 2008. The cumulative risk of CV events after OLT was analyzed with the Kaplan-Meier method. Multivariate logistic regression analysis was used to identify factors independently associated with CV events after OLT. In all, 775 patients were included in our study cohort (mean age of 53.3 years, female proportion = 44%, Caucasian proportion = 84%, median follow-up = 40 months). The most common indications for OLT were hepatitis C virus (33.2%), alcohol (14.5%), and cryptogenic cirrhosis (12.7%). Eighty-three patients suffered 1 or more CV events after OLT. Posttransplant metabolic syndrome was more prevalent in patients with CV events versus patients with no CV events (61.4% versus 34.1%, P < 0.001). According to a multivariate analysis, independent predictors of CV events were an older age at transplantation [odds ratio (OR) = 1.2, addition of 95% confidence interval (CI) = 1.1-1.3, P = 0.006], male sex (OR = 2.0, 95% CI = 1.2-3.3, P = 0.01), posttransplant diabetes (OR = 2.0, 95% CI = 1.3-3.3, P = 0.003), posttransplant hypertension (OR = 1.8, 95% CI = 1.1-3.0, P = 0.02), and mycophenolate mofetil (OR = 2.0, 95% CI = 1.3-3.2, P = 0.003). Among post-OLT patients, the cumulative risk at 5 years of 13.5%, respectively. In conclusion, cardiac complications after liver transplantation are common (Approximately 10% of patients experience 1 or move cv events). Patients with posttransplant hypertension and diabetes, which are modifiable risk factors, are approximately twice as likely to experience a CV event.

Evaluation of liver transplant recipients

The outcome of liver transplantation (LT) is dependent on many factors including graft quality, surgical techniques, postoperative care, immunosuppressive regimens and most importantly, careful pre-transplant recipient evaluation and selection. Currently, the expected 1-year and 5-year survival rates after LT are 85-95% and 75-85%, respectively. The improvement in outcomes and better awareness has resulted in an increasing demand for LT around the world including India. Transplant physicians have responded to this increased demand by developing several strategies including the use of older donors, grafts from hepatitis C positive donors or those with previous hepatitis B infection (positive hepatitis B virus [HBV] core immunoglobulin G [IgG] antibody), graft from nonheart beating donors, domino transplantation (liver from patients with familial amyloid polyneuropathy transplanted into older recipients), split-liver grafts, and live donor liver transplant (LDLT). Currently, the only treatment that prolongs survival in those with end-stage acute or chronic liver failure is transplantation of either partial or full liver donor graft. Because of the enormous disparity in supply and demand for donor organs, costs, and potential morbidity and mortality of live donors in LDLT, it has become incumbent on the transplant community to ration the available organs in a way that provides the best outcomes and in the process, serves the best interest of the population as a whole. When evaluating a potential candidate for LT, it is imperative to determine whether the recipient is going to benefit from the procedure immediately and in the long-term. In this review, we will discuss the process of selection and optimal evaluation of potential LT recipients.

Long-term medical comorbidities and their management: hypertension/cardiovascular disease

1. There is a high prevalence of cardiovascular risk factors in liver transplant recipients. 2. There is a high incidence of premature onset of cardiovascular disease. 3. The choice of calcineurin inhibitor shows no long-term impact. 4. Established cardiovascular risk scores may determine an individual's risk for cardiovascular events. 5. Posttransplant arterial hypertension is a major burden. 6. Strict surveillance guidelines are needed. 7. Threshold levels for arterial blood pressure according to recommendations for high-risk individuals should be applied. 8. Therapeutic lifestyle changes should be encouraged. 9. Escalating pharmacological treatment with respect to renal function is recommended. 10. Alterations of immunosuppression should be considered.

Insulin resistance and microalbuminuria are associated with microvascular disease in patients with cirrhosis

Cardiovascular (CV) disease has a significant impact on post-liver transplantation (LT) survival. Finding surrogate markers for occult CV disease would improve CV assessment in the LT evaluation. This study was designed to determine the prevalence of microvascular disease (MVD) and the utility of both microalbuminuria and the homeostatic model for insulin resistance (HOMA-IR) for assessing the presence of MVD in potential LT recipients. In this study, we examined the prevalence of MVD in 72 diabetics and 71 nondiabetics; both groups were matched for age, sex, race, and etiology of cirrhosis while awaiting LT. We prospectively collected data including fasting serum insulin and glucose levels, urine creatinine and microalbumin, and macrovascular and microvascular complications. MVD was present in 58 (40.5%) patients; MVD was more common in diabetics (n = 45, 62.5%) than nondiabetics (n = 13, 18.3%). The presence of diabetes mellitus (DM; P = 0.03), insulin use (P = 0.002), and duration (months) of DM (85.3 +/- 96.1 versus 22.1 +/- 46.3, P < 0.0001), hypertension (51.3 +/- 101.5 versus 22.7 +/- 58.2, P = 0.03), and hypertriglyceridemia (7.2 +/- 17.4 versus 3.8 +/- 18.5, P = 0.04) were associated with MVD. Significant microalbuminuria had a sensitivity of 85%, a specificity of 100%, and a positive predictive value of 100% for the presence of MVD. HOMA-IR also was associated with MVD (P = 0.0001). In conclusion, at our center, 62.5% of DM patients and 18% of non-DM patients awaiting LT have MVD. Patients with DM, significant microalbuminuria, or an elevated HOMA-IR should undergo rigorous CV assessment prior to LT.

Cardiac evaluation of liver transplant candidates

Physicians previously thought that heart disease was rare in patients with end stage liver disease. However, recent evidence shows that the prevalence of ischemic heart disease and cardiomyopathy is increased in transplant candidates compared to most other surgical candidates. Investigators estimate that up to 26% of all liver transplant candidates have at least one critical coronary artery stenosis and that at least half of these patients will die perioperatively of cardiac complications. Cardiomyopathy also occurs in greater frequency. While all patients with advanced cardiac disease have defects in cardiac performance, a larger than expected number of patients have classical findings of dilated, restrictive and hypertrophic cardiomyopathy. This may explain why up to 56% of patients suffer from hypoxemia due to pulmonary edema following transplant surgery. There is considerable controversy on how to screen transplant candidates for the presence of heart disease. Questions focus upon, which patients should be screened and what tests should be used. This review examines screening strategies for transplant candidates and details the prognostic value of common tests used to identify ischemic heart disease. We also review the physiological consequences of cardiomyopathy in transplant candidates and explore the specific syndrome of “cirrhotic cardiomyopathy”.

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.

Reducing the risks of cardiovascular disease in liver allograft recipients

Liver allograft recipients are at increased risk of death from cerebrovascular and cardiovascular disease. We propose the following strategy of risk-reduction, based on currently available literature. Lifestyle: standard advice should be given (avoidance of smoking, excess alcohol and obesity, adequate exercise, reduction of excess sodium intake). Hypertension: target blood pressure should be 140/90 mmHg or lower, but for those with diabetes or renal disease, 130/80 mmHg or lower. For patients without proteinuria, antihypertensive therapy should be initiated with a calcium channel blocker and for those with proteinuria, an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker. If monotherapy fails to achieve adequate response, calcium channel blockers and ACE-inhibitors or angiotensin II receptor blockers should be combined. If hypertension remains uncontrolled, an alpha-blocker may be added. Consideration should be given to changing immunosuppression and avoiding use of calcineurin inhibitors. Diabetes: recipients should be regularly screened for diabetes. For patients with new-onset diabetes after transplant, stepwise therapy should be guided by HbA1c concentrations, as with type II diabetes mellitus. Hyperlipidemia: annual screening of lipid profile should be undertaken, with treatment thresholds and targets based on those advocated for the high risk general population. Dietary intervention is appropriate for all patients. A statin should be considered as the first line treatment to achieve specified targets. In patients receiving a calcineurin inhibitor, Pravastatin should be commenced at a dose of 10 mg/day. In patients receiving other forms of immunosuppression, pravastatin may be commenced at a dose of 20 mg/day. Liver tests should be monitored and patients warned to report myalgia. If monotherapy is inadequate, ezetimibe or a fibrate may be added. Consideration may be given to change in immunosuppression if combination lipid-lowering therapy proves inadequate.

Validation of cardiovascular risk scores in a liver transplant population

Increased prevalence of cardiovascular risk factors has been acknowledged in liver transplant recipients, and an increased incidence of cardiovascular events has been suspected. Individual risk determination, however, has not yet been established. Outpatient charts of 438 primary liver transplants have been reviewed, and suspected cardiovascular risk factors were correlated with cardiovascular events observed during a follow-up period of 10 yr. Receiver operation characteristics curve (ROC) analysis was performed to validate established cardiovascular risk scores. For calibration, the Hosmer-Lemeshow test was performed. A total of 303 of 438 patients were available for risk factor analysis at 6 months and demonstrated complete follow-up data (175 male, 128 female). A total of 40 of those 303 patients experienced fatal or nonfatal cardiovascular events (13.2%). In univariate analysis, age (P < 0.001), gender (P = 0.002), body mass index (P = 0.018), cholesterol (P = 0.044), creatinine (P = 0.006), diabetes mellitus (P = 0.017), glucose (0.006), and systolic blood pressure (P = 0.043), but not cyclosporine A (P = 0.743), tacrolimus (P = 0.870), or steroid medication (P = 0.991), were significantly associated with cardiovascular events. Multivariate analysis, however, identified only age, gender, and cholesterol as independent predictors. In ROC analysis, corresponding areas under the curve for Systematic Coronary Risk Evaluation Project (SCORE), Prospective Cardiovascular Münster Study (PROCAM), and Framingham risk scores (FRSs) were calculated with 0.800, 0.778, and 0.707, respectively. Calibration demonstrated an improved goodness of fit for PROCAM compared to SCORE risk calculations. In conclusion, SCORE and PROCAM proved to be valuable in discriminating our liver transplant recipients for their individual risk of cardiovascular events. Furthermore, calibrated PROCAM risk estimates are required to calculate the number of patients needed to treat in the setup of prospective intervention trials.