Cardiovascular risk factors and late cardiovascular disease in liver transplantation

Prevalence of hypertension after living-donor liver transplantation: a prospective study

BACKGROUND

Hypertension is common among patients who have undergone liver transplantation and is a major contributor to cardiovascular events. Few studies have studied the risk factors associated with post-liver transplantation (LT) hypertension. This prospective study assessed the prevalence of post-LT hypertension and associated preoperative risk factors.

METHODS

From May 2008 to December 2009, 79 normotensive adult patients (≥ 18 years old) who underwent living-donor LT with a median follow up of 4.79 ± 0.88 years were enrolled. Patients' pre-LT demographics, clinical data, pre-LT diabetes, and immunosuppressive agents used after LT were studied for their association with post-LT hypertension.

RESULTS

The prevalence of post-LT hypertension was 49.4%. The independent risk factors for post-living-donor LT hypertension were pre-LT systolic blood pressure (SBP; odds ratio [OR], 1.04; 95% confidence interval [CI], 1.00-1.09; P = .039) and post-LT administration of mammalian target of rapamycin (mTOR) inhibitors (OR, 4.08; 95% CI, 1.40-11.94; P = .010). Pre-LT diabetes had a negative predictive value (OR, 0.15; 95% CI, 0.03-0.74; P = .019). Neither age, male sex, smoking, pre-LT serum cholesterol and triglyceride levels, tacrolimus, nor glucocorticoid was associated with post-LT hypertension.

CONCLUSIONS

The prevalence of hypertension is high after LT. Higher pre-LT SBP and post-LT mTOR inhibitor administration predispose patients to post-LT hypertension.

Value of stress myocardial perfusion scanning in diagnosis of severe coronary artery disease in liver transplantation candidates

BACKGROUND

The significant potential for perioperative and late cardiovascular complications makes careful preoperative cardiac risk assessment imperative in liver transplantation candidates.

OBJECTIVE

To determine the sensitivity and specificity of myocardial perfusion scanning for detection of coronary artery disease (CAD) in liver transplantation candidates.

PATIENTS AND METHODS

We prospectively evaluated 93 liver transplantation candidates. Patients with known CAD were excluded. All patients, regardless of symptoms and risk factors, underwent myocardial perfusion scanning and coronary angiography.

RESULTS

Results of myocardial perfusion scanning were abnormal in 64 patients (68.8%) and normal in 29 patients (31.2%). Of patients with abnormal scans, only 6 (9.4%) had severe CAD at coronary angiography. None of the 29 patients with normal perfusion scans and the 24 patients with fixed defects had severe CAD; however, 6 of 40 patients (15.0%) with reversible perfusion defects had severe CAD at coronary angiography (P = .005). Alcoholic liver disease, reversible perfusion defects at myocardial perfusion scanning, left ventricular systolic dysfunction, and higher low-density lipoprotein (LDL) cholesterol and triglyceride levels were significantly associated with CAD. Defining reversible perfusion defects as a sign of ischemia, and fixed defects and normal perfusion as nonischemic, myocardial perfusion scanning had 100% sensitivity but 61% specificity for severe CAD. The test's accuracy was low (38%).

CONCLUSIONS

The results of reversible perfusion defects on myocardial perfusion scanning were sensitive but not specific for CAD in liver transplantation candidates. The high number of false-positive results decreased the test's accuracy.

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.

Plasma total homocysteine and cardiovascular risk in patients submitted to liver transplantation

Patients submitted to orthotopic liver transplantation (OLT) show an increased rate of cardiovascular events. OLT subjects have high homocysteine (Hcy) levels, but no data are available on the association of Hcy with cardiovascular events. In a cross-sectional analysis, 230 subjects were studied at least 6 months after OLT (159 on cyclosporine, 71 on tacrolimus). Routine laboratory data and total Hcy were recorded, as well as the history of diabetes, hypertension, dyslipidemia, and overweight. Cardiovascular events occurring in a follow-up of 2-36 months were registered. OLT subjects had higher-than-normal Hcy (median 16.7 micromol/L, range 6.1-171.8) without difference between the 2 immunosuppressive agents. The prevalence of Hcy >15 micromol/L was also similar, and significantly correlated with creatinine levels. A total of 28 arterial events occurred in 25 patients during follow-up (11 in coronary arteries, 10 in peripheral arteries, and 7 in splanchnic arteries). Deep vein thromboses occurred in 2 patients, and splanchnic vein thromboses in 4 patients. Cardiovascular events were frequently associated to high Hcy and hypertension. Cox regression analysis showed that high Hcy was significantly associated with arterial events. The risk of any arterial event, coronary artery or peripheral artery event increased by nearly 10% for any increase in Hcy of 5 micromol/L. In conclusion, high Hcy may be involved in the pathogenesis of cardiovascular events in OLT patients. The usefulness of Hcy-lowering therapy remains to be verified.

Cellular to tissue informatics: approaches to optimizing cellular function of engineered tissue

Tissue engineering is a rapidly expanding, multi-disciplinary field in biomedicine. It provides the ability to manipulate living cells and biomaterials for the purpose of restoring, maintaining, and enhancing tissue and organ function. Scientists have engineered various tissues in the body, from skin substitutes to artificial nerves to heart tissues, with varying degrees of success. Although the field of tissue engineering has come a long way since its first successful demonstration by Bisceglie in the 1930s, methods of coaxing them into functional tissues have been predominantly empirical to date. To successfully develop tissue-engineered organs, it is important to understand how to maintain the cells under conditions that maximize their ability to perform their physiological roles, regardless of their environment. In that context, a methodology that combines empirical data with mathematical and statistical techniques, such as metabolic engineering and cellular informatics, to systematically determine the optimal (1) type of cell to use, (2) scaffold properties and the corresponding processing conditions to achieve those properties, and (3) the required types and levels of environmental factors and the operating conditions needed in the bioreactor, will enable the design of viable and functional tissues tailored to the specific requirements of individual situations.

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

Increased prevalence of cardiovascular risk-factors in liver transplant recipients compared with pretransplant and standard population data has been acknowledged. The impact of risk-profiles on cardiovascular event rates or death, however, has not yet been established. Here we evaluate the development of risk-factors during a prospective follow-up of 10 years in 302 patients and compare numbers of coronary events with data from the German Prospective Cardiovascular Münster (PROCAM)-Score population. Prevalence of overweight (17% vs. 27%), hypertension (70% vs. 80%), and diabetes (21% vs. 25%) increased from early to late after transplantation, while elevated serum cholesterol (64% vs. 37%) and triglycerides (40% vs. 21%) became less frequent. Cardiovascular risk-profiles favoring tacrolimus over ciclosporin A based immunosuppression early after transplantation converged over time. Increased risk-scores in liver transplant recipients matched with score standardized event rates in the PROCAM population (ratio: 1.11, 95% CI: 0.53-2.03), nine events were predicted for the transplant population and oppose 10 events observed. Thus, indicating a reflection of increased cardiovascular risk-profiles in corresponding numbers of cardiovascular events.

Usefulness of preoperative stress perfusion imaging in predicting prognosis after liver transplantation

The role of preoperative stress single-photon emission computed tomographic (SPECT) imaging in patients with end-stage liver disease who underwent liver transplantation is not well established. We reviewed medical records of patients who had liver transplantation at our institution between January 1998 and November 2001. During this time, 339 patients (213 men, aged 51 +/- 11 years) underwent liver transplantation. Of these, 87 patients had preoperative stress SPECT imaging. Diabetes mellitus (30% vs 11%), hypertension (26% vs 12%), and coronary artery disease (15% vs 7%) were more prevalent in those with than without SPECT (p <0.01 each). The stress SPECT perfusion images were normal in 78 patients (91%) and the left ventricular ejection fraction was 72 +/- 10%. SPECT images revealed ascites in 66% and splenomegaly in 83% of patients. There were 35 total deaths (10%) and 5 nonfatal myocardial infarctions over a mean follow-up of 21 +/- 13 months. Most deaths (32 of 35) were noncardiac and sepsis was the most common cause of death. A normal SPECT study had a 99% negative predictive value for perioperative cardiac events. Kaplan-Meier survival curves showed an 87% 2-year cumulative survival rate in the total group. Thus, in patients undergoing liver transplantation, 2-year survival depends on early noncardiac events. A normal stress SPECT study identified patients at a very low risk for early and late cardiac events despite a higher risk profile. SPECT images also revealed unique findings, such as ascites and splenomegaly, which could produce image artifacts and may interfere with accurate image interpretation.

Immunosuppression impact on long-term cardiovascular complications after liver transplantation

BACKGROUND

With current early transplant patient and allograft survivals nearly optimized, long-term medical complications have become a significant focus for potential improvement in patient outcomes. Cardiovascular disease and associated risk factors have been shown in renal transplant patients to be related to the pharmacologic immunosuppression employed.

OBJECTIVE

The objective of this study is to investigate at 3 years postliver transplant (OLTx) the incidence of hypertension (HTN), hyperlipidemia (HLIP), diabetes mellitus (DM), nephrotoxicity (NTX), and cardiovascular disease (MI, angioplasty, CHF, CVA, and seborth) as well as rejection in two cohorts of liver transplant recipients who received either tacrolimus (FK-506) or cyclosporine (CSA) and to analyze the consequences of these complications on mortality following transplantation.

METHODS

Eighty-seven sequential patients (CSA: n = 50, mean age 48 years, M/F 32/18; and FK-506: n = 37, mean age 45 years, M/F 22/15) who underwent OLTx between 1994 and 1998, were >/=18 years, and had a minimum of 3 years of complete follow-up were included in the analysis. All OLTx candidates over age 50, who had a history of alcoholic cirrhosis, or had a history of cardiac conditions/events underwent complete cardiac consultation including an echocardiogram with additional cardiac investigation as indicated prior to OLTx.

RESULTS

At 3 years following OLTx, the incidence of acute rejection (40% versus 19%, P < 0.05), HTN (62% versus 38%, P < 0.05), HLIP (14% versus 5%, P = 0.08), and cardiovascular disease (18% versus 0%, P < 0.001), were significantly greater for the CSA patients compared with the FK-506 patients. Eight (20%) of the CSA patients who died before 3 years had their death attributed to cardiovascular events versus none in the FK-506 group.

CONCLUSION

Compared with CSA, FK-506 was associated with significantly less rejection and a reduced incidence of HTN and cardiovascular disease.