Vascular endothelial growth factor, left ventricular dysfunction and mortality in hemodialysis patients.

OBJECTIVES: Vascular endothelial growth factor induces nitric oxide-dependent angiogenic effects and participates in the inflammatory response. This cytokine is over-expressed in the myocardium in experimental models of pressure overload and renal mass ablation, and vascular endothelial growth factor is increased in end-stage renal disease. We investigated the relationship between vascular endothelial growth factor, left ventricular function (by midwall fractional shortening) and mortality in a prospective cohort study in 228 hemodialysis patients. RESULTS: Serum vascular endothelial growth factor concentration was associated directly with interleukin-6 and tumor necrosis factor-alpha (P < 0.01) and inversely with albumin (P = 0.007) but was independent of the endogenous inhibitor of nitric oxide synthesis, asymmetric dimethylarginine. Vascular endothelial growth factor was inversely related with midwall fractional shortening (P = 0.002) and predicted mortality (P = 0.02). In multivariate analyses testing the involvement of this angiogenic cytokine in left ventricular dysfunction and death, these links remained substantially unmodified after adjustment for Framingham risk factors, risk factors peculiar to end-stage renal disease (Hb, Ca, P) and previous cardiovascular complications. However, these links became weaker and not significant when biomarkers of inflammation and asymmetric dimethylarginine were sequentially introduced into the multivariate models. In crude and adjusted analyses, left ventricular function was lowest in patients who displayed both high vascular endothelial growth factor and high asymmetric dimethylarginine, intermediate in patients with either high vascular endothelial growth factor or high asymmetric dimethylarginine and highest in those with low asymmetric dimethylarginine and low vascular endothelial growth factor (P = 0.001). CONCLUSION: Vascular endothelial growth factor is associated with left ventricular systolic dysfunction and mortality in hemodialysis patients. Vascular endothelial growth factor appears to be in the pathway whereby inflammation and nitric oxide inhibition lead to cardiomyopathy and death in hemodialysis patients.

An additive effect of endothelial nitric oxide synthase gene polymorphisms contributes to the severity of atherosclerosis in patients on dialysis.

BACKGROUND: Reduced synthesis of nitric oxide (NO) is considered a major proatherogenic mechanism in patients with end-stage renal disease (ESRD), but genetic factors impinging on this mechanism have been little studied in this population. METHODS: We tested the relationship between carotid intima-media thickness (IMT) and three endothelial NO synthase (eNOS) polymorphisms (G894T, T-786C, and 27-bp repeat in intron 4) in an ethnically and geographically homogeneous group of 147 patients with ESRD. RESULTS: The IMT was significantly thicker (P = .01) in patients with the TT genotype (G894T polymorphism) than in patients with TG or GG genotypes, and a similar association was observed for the T-786C polymorphism (P = .02). These relationships remained statistically significant (P = .02 and .01), also in multivariate models including traditional and emerging risk factors for atherosclerosis. Moreover, there was a direct association between the number of risk alleles and IMT (no risk allele: 0.97 +/- 0.22 mm, 1 risk allele: 1.03 +/- 0.20 mm, 2 risk alleles: 1.07 +/- 0.22 mm, > or =3 risk alleles: 1.23 +/- 0.36 mm, P < .001) that remained statistically significant in a multiple regression model. CONCLUSIONS: In patients on dialysis the risk alleles of G894T and T-786C polymorphisms of the eNOS gene are associated with carotid atherosclerosis. The additive effect of the two polymorphisms may contribute to the severity of atherosclerosis independently of other risk factors and of endogenous substances that influence the NO synthesis in this population.

Atherosclerosis and the Glu298Asp polymorphism of the eNOS gene in white patients with end-stage renal disease.

BACKGROUND: We investigated whether the eNOS G/T polymorphism (Glu298Asp variant) is linked to the severity of carotid atherosclerosis and whether it is independent of asymmetric dimethylarginine (ADMA) in determining vascular damage in patients with end-stage renal disease (ESRD). METHODS: The eNOS polymorphism, ADMA, carotid intima-media thickness (IMT), and carotid artery (CCA) wall-to-lumen ratio (an indicator of arterial remodeling) were determined/measured in 131 patients with ESRD. RESULTS: Both in the co-dominant and dominant model approach, IMT as well as CCA wall-to-lumen ratio were directly related to the T allele (P < or = .009) and these relationships held true in multiple linear regression analyses including ADMA and traditional and emerging risk factors. The relationship between eNOS genotypes and CCA wall-to-lumen ratio was further analyzed by a categorical approach and in a multiple logistic regression analysis, the odds ratio (OR) of increased CCA wall-to-lumen ratio was strongly associated to the T allele (codominant model: GG, OR = 1; GT, OR = 2.1; TT, OR = 8.2; P for trend = .01; dominant model: GG, OR = 1; GT and TT, OR = 2.7; P = .02). CONCLUSIONS: The T allele of eNOS gene is an independent predictor of intimal lesions and vascular remodeling and it is associated with the severity of atherosclerosis independently of ADMA.

Neuropeptide Y, left ventricular mass and function in patients with end stage renal disease.

OBJECTIVE: Neuropeptide Y (NPY) is released during sympathetic stimulation and mediates the central effects of the adipostatic hormone leptin. The plasma concentration of NPY and leptin is increased in patients with end stage renal disease (ESRD), but it is unknown whether these substances are related to biochemical markers of sympathetic activity and to alterations in left ventricular (LV) mass and function in these patients. DESIGN: We investigated the relationship between NPY, norepinephrine (NE), leptin and echocardiographic measurements in a cross-sectional study in 198 patients with ESRD. RESULTS: NPY was directly related to plasma NE and heart rate but it was largely independent of arterial pressure and of retention of metabolic waste products. NPY was significantly higher in patients with LV hypertrophy and in those with LV systolic dysfunction than in those without these alterations. Of note, NPY emerged as an independent correlate of LV mass index and of LV ejection fraction (LVEF) (both P

Heart valve calcifications, survival, and cardiovascular risk in hemodialysis patients.

BACKGROUND: Cardiovascular (CV) calcifications constitute a strong risk marker, and recent studies in continuous ambulatory peritoneal dialysis patients have associated valvular calcifications to inflammation, mortality, and CV events. The prognostic value of cardiac valve calcifications and their relationship with left ventricular hypertrophy and background cardiovascular risk in hemodialysis patients is still unknown. METHODS: The prognostic value of heart valve calcifications (detected by echocardiography) for all-cause and CV death was tested in a cohort of 202 hemodialysis (HD) patients. RESULTS: Forty-seven patients had 1 or more calcified valves. Background CV complications were more frequent (P = 0.001) and left ventricular hypertrophy was more severe (P < 0.001) in patients with calcified valves than in those without this alteration. During the follow-up period (44 +/- 23 months), 96 patients died, 66 patients (69%) of CV causes. Valve calcifications were significantly associated with all-cause (P = 0.02) and CV mortality (P < or = 0.001). However, in statistical models adjusting for traditional and nontraditional CV risk factors and background CV complications and left ventricular mass index (LVMI), the relationship between calcified valves and incident all-cause and CV mortality was not significant. CONCLUSION: In HD patients, cardiac valve calcifications predict all-cause and CV mortality in unadjusted analyses, but these associations are not evident in models adjusting for background CV complications, LVMI, and other risk factors. Cardiac valve calcifications do not provide an independent contribution in the prediction of death and CV mortality.

Troponin is related to left ventricular mass and predicts all-cause and cardiovascular mortality in hemodialysis patients.

Cardiac troponin T (cTnT) predicts death and cardiovascular outcomes in clinically stable patients with end-stage renal disease. Because this protein is synthesized exclusively in myocardial cells, its predictive power for these outcomes may be because it reflects, besides cardiac ischemia, left ventricular (LV) mass, which is a strong predictor of cardiovascular death in this population per se. We tested the relationship between cTnT level and LV mass and the predictive power of this cardiac protein for all-cause and cardiovascular mortality in a cohort of hemodialysis patients (n = 199) without acute coronary syndrome and heart failure followed up for an average of 35 months (range, 0.8 to 52 months). cTnT was measured by means of a third-generation electrochemiluminescence immunoassay. cTnT level was related directly to interventricular septum (r = 0.36; P < 0.001) and posterior wall thickness (r = 0.40; P < 0.001), as well as LV mass (r = 0.45; P < 0.001). On multivariate analysis, after age, LV mass was the strongest independent predictor of cTnT level (beta = 0.28; P < 0.001). Serum cTnT level was significantly related to all-cause and cardiovascular mortality on univariate analysis (P < 0.001). On multivariate Cox regression analysis, the adjusted risk for all-cause death was 2.39 times (95% confidence interval [CI], 1.13 to 5.06; P = 0.02) greater in patients in the third cTnT tertile than the first tertile, and a similar pattern emerged for cardiovascular mortality (hazard ratio, 2.35; 95% CI, 1.01 to 5.49; P = 0.048). In hemodialysis patients, plasma cTnT level is independently related to LV mass and predicts all-cause and cardiovascular mortality. These data support the hypothesis that this marker can be usefully applied for risk stratification in clinically stable dialysis patients.

eNOS and caveolin-1 gene polymorphisms interaction and intima media thickness: a proof of concept study in ESRD patients.

BACKGROUND: Caveolae are a prominent microdomain in endothelial cells and appropriate localization in caveolae is fundamental for endothelial nitric oxide synthase (eNOS) activity. Since the Glu298Asp variant in the eNOS gene alters caveolar localization of the corresponding enzyme, we tested the interaction between this variant and the rs4730751 polymorphism of the caveolin-1 (CAV-1) gene as related to arterial remodeling in end-stage renal disease (ESRD) patients. METHODS: One hundred and thirty-three ethnically homogeneous ESRD patients underwent carotid ultrasonographic studies to measure intima-media thickness (IMT) and carotid cross-sectional area (CSA). Genotyping was performed by high-throughput allelic discrimination assays on real-time PCR. RESULTS: Arterial remodeling was associated to the number of G alleles of CAV-1 polymorphism, GG homozygotes displaying an IMT and a CSA that were, respectively, 16% and 21% higher than those in patients without the risk allele (P < 0.012). In multiple linear regression analyses including the CAV-1 and the eNOS polymorphisms and adjusting for classical risk factors and risk factors peculiar to ESRD both polymorphisms were independent correlates of IMT (CAV-1: ß = 0.20, P = 0.01; eNOS ß = 0.25, P = 0.001) and CSA (CAV-1: ß = 0.20, P = 0.01: eNOS ß = 0.13, P = 0.09). Furthermore, strong interactions emerged between the two polymorphisms for explaining the variability in IMT (P = 0.001) and in CSA (P = 0.038) in these patients. CONCLUSION: Overall these findings form preliminary evidence that disturbed interaction between CAV-1 and eNOS may be of relevance for arterial disease in ESRD and perhaps in other human diseases.

Detection of pulmonary congestion by chest ultrasound in dialysis patients.

OBJECTIVES: This study sought to investigate clinical and echocardiographic correlates of the lung comets score. BACKGROUND: Early detection of pulmonary congestion is a fundamental goal for the prevention of congestive heart failure in high-risk patients. METHODS: We undertook an inclusive survey by a validated ultrasound (US) technique in a hemodialysis center to estimate the prevalence of pulmonary congestion and its reversibility after dialysis in a population of 75 hemodialysis patients. RESULTS: Chest US examinations were successfully completed in all patients (N = 75). Before dialysis, 47 patients (63%) exhibited moderate to severe lung congestion. This alteration was commonly observed in patients with heart failure but also in the majority of asymptomatic (32 of 56, 57%) and normohydrated (19 of 38, 50%) patients. Lung water excess was unrelated with hydration status but it was strongly associated with New York Heart Association functional class (p < 0.0001), left ventricular ejection fraction (r = -0.55, p < 0.001), early filling to early diastolic mitral annular velocity (r = 0.48, p < 0.001), left atrial volume (r = 0.39, p = 0.001), and pulmonary pressure (r = 0.36, p = 0.002). Lung water reduced after dialysis, but 23 patients (31%) still had pulmonary congestion of moderate to severe degree. Lung water after dialysis maintained a strong association with left ventricular ejection fraction (r = -0.59, p < 0.001), left atrial volume (r = 0.30, p = 0.01), and pulmonary pressure (r = 0.32, p = 0.006) denoting the critical role of cardiac performance in the control of this water compartment in end-stage renal disease. In a multiple regression model including traditional and nontraditional risk factors only left ventricular ejection fraction maintained an independent link with lung water excess (beta = -0.61, p < 0.001). Repeatability studies of the chest US technique (Bland-Altman plots) showed good interobserver and inter-US probes reproducibility. CONCLUSIONS: Pulmonary congestion is highly prevalent in symptomatic (New York Heart Association functional class III to IV) and asymptomatic dialysis patients. Chest ultrasound is a reliable technique that detects pulmonary congestion at a pre-clinical stage in end-stage renal disease.

Vitamin D receptor (VDR) gene polymorphism is associated with left ventricular (LV) mass and predicts left ventricular hypertrophy (LVH) progression in end-stage renal disease (ESRD) patients.

Left ventricular hypertrophy (LVH) is a strong cardiovascular risk marker in end-stage renal disease (ESRD) patients. Vitamin D deficiency and/or disturbed vitamin D signaling has been implicated in LVH in experimental models. Because the BsmI vitamin D receptor VDR gene polymorphism may alter VDR function, we performed a cross-sectional and longitudinal study in a cohort of 182 dialysis patients to investigate (1) the relationship between BsmI VDR gene polymorphism and left ventricular mass index (LVMI) measured by echocardiography and (2) the predictive power of this polymorphism for progression in LVH over a 18 +/- 2 months of follow-up. As a reference group, we used 175 healthy subjects matched to the study population as for age and sex. The distribution of BsmI genotypes did not significantly deviate from Hardy-Weinberg equilibrium either in patients or in the control group of healthy subjects. The frequency of the B allele of BsmI polymorphism (40.4%) in dialysis patients was similar to that of healthy control subjects (38.6%), and the number of B alleles was directly related to LVMI (r = 0.20, P = .007). This relationship remained robust (beta = 0.19, P = .006) in multivariate analysis adjusting for traditional and nontraditional risk factors and antihypertensive and calcitriol treatment. In the longitudinal study, LVMI rose from 60.1 +/- 17.9 to 64.2 +/- 19.3 g/m(2.7) (P < .001), and again, the number of B alleles was associated with LVMI changes both in crude and in fully adjusted analyses. These cross-sectional and longitudinal observations coherently support the hypothesis that altered vitamin D signaling is implicated in LVH in ESRD patients.

Neuropeptide Y receptor Y2 gene polymorphism interacts with plasma neuropeptide Y levels in predicting left ventricular hypertrophy in dialysis patients.

BACKGROUND: Neuropeptide Y (NPY) is a sympathetic neurotransmitter that acts on multiple receptors involved in cardiovascular remodelling and angiogenesis. Plasma levels of NPY are increased in patients with end-stage renal disease (ESRD) and are independently related to left ventricular hypertrophy (LVH) and incident cardiovascular events in these patients. OBJECTIVE: To investigate the relationship between NPY receptor Y2 gene polymorphism and left ventricular mass index (LVMI) as well as the interaction between this polymorphism and plasma NPY in determining LVH in 189 ESRD patients. RESULTS: LVMI was significantly higher (+12%, P = 0.03) in patients carrying the C allele than in those without C allele and was linearly associated with plasma NPY (P = 0.01). Interaction analysis showed a significant NPY-LVMI relationship in patients with the C allele, both at univariate (r = 0.27, P = 0.001) and multivariate (r = 0.21, P = 0.01) analyses, whereas no such relationship existed in patients without this allele. In fully adjusted analyses, a 10 pmol/l increase in plasma NPY entailed a 4.9 g/m increase in LVMI in patients with C allele, whereas the same change in NPY levels did not modify the NPY-LVMI link in patients without such allele (P = 0.009). CONCLUSION: NPY receptor Y2 polymorphism is independently associated with LVMI and interacts with plasma levels of NPY in explaining the variability of LVH in ESRD. These results offer a genetic basis to the hypothesis that NPY is causally implicated in the pathogenetic pathway leading to LVH in ESRD patients.

Left ventricular systolic function monitoring in asymptomatic dialysis patients: a prospective cohort study.

Although it is well established that compromised systolic function predicts cardiovascular (CV) complications in symptomatic and asymptomatic patients with ESRD, it still is unknown whether repeated echocardiographic measurements of systolic function in asymptomatic patients with ESRD is useful for monitoring the evolution of cardiomyopathy in these patients. The prognostic value for CV events of changes in systolic function, as measured by midwall fractional shortening (mwFS) in a cohort of 191 dialysis patients, was tested. Echocardiography was performed twice, 17 +/- 2 mo apart. Changes in mwFS (ch-mwFS) that occurred between the second and the first echocardiographic studies then were used to predict CV events during the ensuing 27 +/- 13 mo. After the second echocardiographic study, 85 patients had incident CV events. In a Kaplan-Meier analysis, there was a graded increase in the risk for fatal and nonfatal CV events across ch-mwFS quartiles (P = 0.005). On multivariate Cox regression analysis, ch-mwFS maintained an independent association with CV outcomes. In this analysis, the risk for CV events was 51% lower in patients who manifested an increase in mwFS (hazard ratio 0.49; 95% confidence interval 0.27 to 0.88; P = 0.02) than in those who had a decrease in mwFS. Changes in mwFS have an independent prognostic value for CV events, and periodic echocardiographic studies of systolic function are useful for monitoring asymptomatic dialysis patients.

The E-selectin gene polymorphism and carotid atherosclerosis in end-stage renal disease.

BACKGROUND: E-selectin is a cell surface glycoprotein that mediates the adhesion of leucocytes to vessels endothelium, an important early step in the atherosclerotic process. End-stage renal disease (ESRD) is a highly atherogenic disease but it is unknown whether genetic polymorphism(s) in the E-selectin gene plays a role in the severity of arterial damage in this condition. Method. In this study, we tested whether the Leu554Phe variant in the E-selectin gene is linked to carotid atherosclerosis in 134 well-characterized ESRD patients. The frequency of this polymorphism was also measured in a population sample of the same geographical area. RESULTS: A total of 84% patients had the CC genotype, 13% had the CT genotype, 3% had the TT genotype and this distribution did not differ from that in the control population. Intima-media thickness (IMT) (P = 0.01) and cross-sectional area (P = 0.02) were significantly higher in patients with the T-allele than in those without this allele. Furthermore, the degree of carotid stenosis was significantly higher (P = 0.02) in patients with T-allele than in CC patients. On multivariate analyses including the traditional and non-traditional risk factors, the Leu554Phe polymorphism was confirmed as an independent correlate of IMT (P = 0.02), cross-sectional area (P = 0.03) and carotid stenosis (P = 0.02). CONCLUSION: In ESRD, the Leu554Phe polymorphism of E-selectin gene is associated with the severity of carotid atherosclerosis, suggesting that genetically-determined alterations in the E-selectin molecule may render ESRD patients with this gene variant particularly susceptible to the detrimental effects of inflammation on the arterial wall.

Left ventricular mass monitoring in the follow-up of dialysis patients: prognostic value of left ventricular hypertrophy progression.

BACKGROUND: Regression of left ventricular hypertrophy (LVH) in the setting of a well-planned intervention study has been associated with longer survival in hemodialysis patients. Whether changes in left ventricular mass (LVM) in clinical practice predict survival and cardiovascular events in these patients is still unknown. METHODS: In a prospective study in 161 hemodialysis patients we tested the prognostic value of changes in LVM on survival and incident cardiovascular events. Echocardiography was performed twice, 18 +/- 2 SD months apart. Changes in LVM occurring between the first and the second echocardiographic study were then used to predict mortality and cardiovascular events during the ensuing 29 +/- 13 months. The prognostic value of LVM changes was tested in a multivariate Cox's model with LVM index (LVMI) [expressed as LVM/height(2.71)], included as a covariate to control for regression to the mean. RESULTS: The rate of increase of LVMI was significantly (P= 0.029) higher in patients with incident cardiovascular events than in those without such events. Accordingly, cardiovascular event-free survival in patients with changes in LVMI below the 25th percentile was significantly (P= 0.004) higher than in those with changes above the 75th percentile. In a multiple Cox regression analysis, including age, diabetes, smoking, homocysteine, 1 g/m(2.7)/month increase in LVMI was associated with a 62% increase in the incident risk of fatal and nonfatal cardiovascular events [hazard ratio 1.62 (95% CI 1.13-2.33), P= 0.009]. CONCLUSION: Changes in LVMI have an independent prognostic value for cardiovascular events and provide scientific support to the use of repeated echocardiographic studies for monitoring cardiovascular risk in dialysis patients.

Prognostic value of echocardiographic indicators of left ventricular systolic function in asymptomatic dialysis patients.

Patients with end-stage renal disease (ESRD) are at high risk for heart failure, but the prevalence and the prognostic value of asymptomatic systolic dysfunction in these patients are unknown. In this prospective cohort study, the authors have therefore assessed by echocardiography the prevalence and the prognostic value of systolic function as estimated by ejection fraction (EF), fractional shortening at endocardial level (endoFS), and at midwall (mwFS), in a cohort of 254 asymptomatic dialysis patients. Systolic dysfunction had a prevalence rate of 26% by endoFS and of 48% by mwFS. During the follow-up period, 125 patients had one or more fatal and nonfatal CV events. On multivariate COX regression analysis, the three LV systolic function indicators were independently associated with incident fatal and nonfatal CV events, and there were no differences in the predictive power of these indicators (P > 0.30). The prediction power of LV function indicators was largely independent of traditional and novel risk factors in ESRD such as C-reactive protein and asymmetric dimethyl arginine (ADMA). ADMA was significantly related with LV function indicators as well as with mortality and incident CV events, but these links were much reduced (P = NS) in models including LV function indicators. Of note, the risk of CV events was minimal in patients with normal LV mass and function, intermediate in patients with either LVH or systolic dysfunction, and maximal in patients displaying both alterations. The study of myocardial contractility by echocardiography provides prognostic information independently of LV mass and other risk factors in ESRD. Risk stratification by simple systolic function parameters may prove useful in secondary prevention strategies in these patients.

Hepatocyte growth factor and left ventricular geometry in end-stage renal disease.

Hepatocyte growth factor is a pleiotropic cytokine with cardioprotective properties. Its serum concentration is markedly raised in end-stage renal disease. This study assessed the relation of hepatocyte growth factor (HGF) with left ventricular mass and geometry in end-stage renal disease. Serum HGF measurements and echocardiographic studies were performed in 185 patients receiving hemodialysis. Patients with serum HGF above the median (1.85 ng/mL) had more frequent cardiovascular complications. This cytokine was directly related to mean left ventricular wall thickness (r=0.23, P=0.002) and relative wall thickness (r=0.25, P=0.0001); a multivariate analysis showed that this relation was independent of other risk factors. Accordingly, the prevalence of left ventricular concentric geometry (either concentric left ventricular hypertrophy or remodeling) was much higher (n=49, 53%) among patients with HGF values above the median that in those with values < or =1.85 ng/mL (n=31, 34%). Furthermore, the risk for left ventricular concentric geometry was higher in patients with HGF values above the median (odds ratio, 2.57; 95% CI, 1.33 to 4.98; P=0.005), and multiple logistic regression analysis confirmed that this association was independent of other risk factors. In patients receiving hemodialysis, elevated serum HGF is associated with concentric left ventricular geometry. This is consistent with reports that link this cytokine to arterial remodeling and survival in patients with end-stage renal disease and suggests that it is part of a counterregulatory response aimed at attenuating cardiovascular damage in this high-risk population.

Hyperhomocysteinemia predicts cardiovascular outcomes in hemodialysis patients.

BACKGROUND: We prospectively tested the prediction power of homocysteinemia for all-cause and cardiovascular outcomes in a cohort of 175 hemodialysis patients followed for 29 +/- 12 months. METHODS: Survival analysis was performed by the Cox's proportional hazard model and data were expressed as hazard ratio and 95% confidence interval (CI). RESULTS: During the follow-up period 51 patients died, 31 of them (61%) of cardiovascular causes and 16 patients developed non-fatal atherothrombotic complications. Plasma total homocysteine was an independent predictor of cardiovascular mortality (P=0.01). Combined analysis of fatal and non-fatal atherothrombotic events showed that homocysteine was a strong and independent predictor of these outcomes because the risk of these events was 8.2 times higher (95% CI 1.9 to 32.2) in patients in the third homocysteine tertile than in those in the first tertile (P=0.005). CONCLUSIONS: There is a clear association between hyperhomocysteinemia and incident cardiovascular mortality and atherothrombotic events in hemodialysis patients. Intervention studies are needed to determine whether the accumulation of this substance has a causal role in the pathogenesis of cardiovascular damage in patients undergoing hemodialysis.

Left ventricular hypertrophy, cardiac remodeling and asymmetric dimethylarginine (ADMA) in hemodialysis patients.

BACKGROUND: The endogenous inhibitor of nitric oxide (NO), asymmetric dimethylarginine (ADMA), is a strong predictor of adverse cardiovascular outcomes in patients with end-stage renal disease (ESRD). METHODS: Since arterial and cardiac remodeling is associated with altered endothelial microcirculatory responses to forearm ischemia (a NO-dependent response), interference of ADMA with the NO system may be important for the pathogenesis of left ventricular hypertrophy (LVH) in these patients. This study sought to identify the relationship between plasma ADMA and LV geometry and function in a cohort of 198 hemodialysis patients. RESULTS: Plasma ADMA was significantly higher (P = 0.008) in patients with LVH (median 3.00 micromol/L, inter-quartile range 1.73 to 3.97 micromol/L) than in those without this alteration (1.88 micromol/L, 1.15 to 3.56 micromol/L) and was significantly related to left ventricular (LV) mass (r = 0.26, P < 0.001). Interestingly, ADMA was much higher (P < 0.001) in patients with concentric LVH (3.60 micromol/L, 2.90 to 4.33 micromol/L) than in patients with eccentric LVH (2.17 micromol/L, 1.47 to 3.24 micromol/L) or normal LV mass (1.76 micromol/L, 1.13 to 2.65 micromol/L). Furthermore, plasma ADMA was higher (P = 0.02) in patients with systolic dysfunction (3.52 micromol/L, 2.08 to 5.87 micromol/L) than in those with normal LV function (2.58 micromol/L, 1.53 to 3.84 micromol/L) and inversely related to ejection fraction (EF; r = -0.25, P < 0.001). The link between ADMA and LV mass and EF was confirmed by multivariate analysis (ADMA vs. LVMI, beta = 0.17, P = 0.006; ADMA vs. EF, beta = -0.24, P < 0.001). CONCLUSIONS: Overall, this study indicates that raised plasma concentration of ADMA is associated to concentric LVH and LV dysfunction. Intervention studies are needed to see whether the link between ADMA and concentric LVH remodeling and LV dysfunction is a causal one.

Prospective study of neuropeptide y as an adverse cardiovascular risk factor in end-stage renal disease.

Chronic renal insufficiency is a situation characterized by high plasma concentration of neuropeptide Y (NPY). Because this neuropeptide interferes with cardiovascular (CV) function, it is possible that it is involved in the high CV-related morbidity and mortality of these patients. To test this hypothesis, a follow-up study was performed (average duration, 34 mo; range 0.2 to 52.0 mo) in a cohort of 277 patients with end-stage renal disease receiving chronic dialysis. Univariate analysis revealed that plasma NPY was directly related to plasma norepinephrine (r = 0.37, P < 0.001) and epinephrine (r = 0.17, P = 0.005), exceeding the upper limit of the normal range in the majority of patients with end-stage renal disease (170 of 277, 61%). One hundred thirteen patients had one or more fatal and nonfatal CV events; 112 patients died, 66 of them (59%) of CV causes. Plasma NPY failed to predict all-cause mortality but was an independent predictor of adverse CV outcomes (hazard ratio [10 pmol/L increase in plasma NPY], 1.32; 95% confidence interval, 1.09 to 1.60; P = 0.004) in a Cox proportional-hazard model that included a series of traditional and nontraditional CV risk factors. Plasma NPY maintained its predictive power for CV events in statistical model including plasma norepinephrine. Plasma NPY predicts incident CV complications in end-stage renal disease. Controlled trials are needed to establish whether interference with the sympathetic system, NPY, or both may reduce the high CV morbidity and mortality of dialysis patients.

Diagnostic value of troponin T for alterations in left ventricular mass and function in dialysis patients.

BACKGROUND: Cardiac troponin T (cTnT) is related to left ventricular (LV) mass in patients with end-stage renal disease (ESRD). Furthermore, cTnT reflects the severity of systolic dysfunction in patients with heart diseases. We tested the diagnostic value of cTnT for left ventricular hypertrophy (LVH) and LV systolic dysfunction in a large group of clinically stable hemodialysis patients without heart failure. RESULTS: CTnT was significantly (P < 0.001) higher in patients with LVH than in those with normal LV mass. In a multiple logistic regression model, adjusting for potential confounders (including cardiac ischemia), systolic pressure and cTnT (both P = 0.003) were the strongest correlates of LVH. Similarly, cTnT was significantly higher (P = 0.005) in patients with systolic dysfunction than in those with normal LV function and in a multiple logistic regression model cTnT ranked as the second independent correlate of this alteration after male sex. Serum cTnT had a high positive prediction value for the diagnosis of LVH (87%) but its negative prediction value was relatively low (44%). The positive predictive value of cTnT for LV dysfunction was low (25%) while its negative predictive value was high (93%). A combined analysis including systolic pressure (for the diagnosis of LVH) and sex (for the diagnosis of LV systolic dysfunction) augmented the diagnostic estimates to an important extent (95% positive prediction value for LVH and 98% negative prediction value for LV systolic dysfunction). CONCLUSIONS: CTnT has a fairly good diagnostic potential for the identification of LVH and for the exclusion of LV systolic dysfunction in patients with ESRD without heart failure. This marker may be useful for the screening of alterations in LV mass and function in clinically stable hemodialysis patients.

Adiponectin, metabolic risk factors, and cardiovascular events among patients with end-stage renal disease.

Adiponectin (ADPN), which is a secretory protein of adipose tissue, attenuates endothelial inflammatory responses in vitro. Among human subjects, plasma ADPN concentrations are reduced among patients with atherosclerotic complications but are substantially increased among patients with advanced renal failure. The clinical and biochemical correlates of plasma ADPN levels were investigated and the predictive power of ADPN levels with respect to survival rates and cardiovascular events was prospectively tested in a cohort of 227 hemodialysis patients, who were monitored for 31 +/- 13 mo. Plasma ADPN levels were 2.5 times higher (P < 0.0001) among dialysis patients (15.0 +/- 7.7 microg/ml) than among healthy subjects (6.3 +/- 2.0 microg/ml), were independent of age, and were higher (P = 0.03) among women (15.2 +/- 7.9 microg/ml) than among men (14.0 +/- 7.4 microg/ml). For both genders, plasma ADPN levels were inversely related to body mass index values, plasma leptin levels, insulin levels, serum triglyceride levels, and homeostatic model assessment index values. Furthermore, plasma ADPN levels were directly related to HDL cholesterol levels and inversely related to von Willebrand factor levels. Plasma ADPN levels were lower (P < 0.05) among patients who experienced new cardiovascular events (13.7 +/- 7.3 microg/ml) than among event-free patients (15.8 +/- 7.8 microg/ml). There was a 3% risk reduction for each 1 microg/ml increase in plasma ADPN levels, and the relative risk of adverse cardiovascular events was 1.56 times (95% confidence interval, 1.12 to 1.99 times) higher among patients in the first ADPN tertile, compared with those in the third tertile. Plasma ADPN levels are an inverse predictor of cardiovascular outcomes among patients with end-stage renal disease. Furthermore, ADPN is related to several metabolic risk factors in a manner consistent with the hypothesis that this protein acts as a protective factor for the cardiovascular system.