Intima media thickness as a predictor of atherosclerosis in renal transplantation

Role of cytomegalovirus infection after kidney transplantation on the subsequent risk of atherosclerotic and thrombotic events

Background and aims

Whether cytomegalovirus (CMV) infection increases the risk of cardiovascular complications after kidney transplantation (KT) through different indirect effects remains controversial.

Methods

We analyzed the incidence of post-transplant atherosclerotic (PAEs) and thrombotic events (PTEs) in 465 KT recipients according to the previous exposure to any level or high-level (≥1,000 IU/mL) CMV viremia (either asymptomatic or clinical disease) by means of landmark analysis beyond days 30, 180 and 360 after transplantation. Proportional hazards models were constructed with death and graft loss as competing risks.

Results

After a median of 722 days, the cumulative incidences of PAE and PTE were 6.0% each. Most PAEs (53.6%) occurred beyond post-transplant day 360, whereas most PTEs (60.7%) were diagnosed between days 30-180.The incidence of PAE beyond day 180 was higher among patients with previous CMV viremia compared to those without (two-year rates: 4.7% versus 0.4%; P-value = 0.035). This difference was more pronounced in recipients developing high-level viremia (6.3% versus 0.7%, respectively; P-value = 0.013). After multivariate adjustment for age, pre-transplant cardiovascular risk, antiplatelet and statin therapy and graft function, however, associations were not maintained either for any-level (hazard ratio [HR]: 1.84; 95% confidence interval [CI]: 0.48-7.05) or high-level CMV viremia (HR: 2.84; 95% CI: 0.78-10.36). No significant differences were found in the remaining landmark analyses (days 30 or 360) or for the outcome of PTE either.

Conclusions

Our study does not support that CMV infection independently contributes to the risk of PAE or PTE after KT.

A critical review of the relationship between post-transplant atherosclerotic events and cytomegalovirus exposure in kidney transplant recipients

Introduction: Cytomegalovirus (CMV) infection after kidney transplantation (KT) has been implicated in the so-called 'indirect effects' attributable to the viral ability to evade host's immunity and trigger sustained inflammation. Whether CMV exposure contributes to the development of post-transplant atherosclerotic events (AEs) remains controversial.Areas covered: This review (based on a PubMed/MEDLINE search from database inception to October 2019) summarizes the proposed mechanisms for the role of CMV in atherogenesis, including accelerated immunosenescence, endothelial injury and inflammatory milieu in the vessel wall. Sero-epidemiological evidence linking CMV exposure and cardiovascular disease in the general population is discussed. Finally, we performed a comprehensive review of observational studies investigating the impact of CMV infection on the occurrence of AE after KT, as well as the potential protective effect of antiviral prophylaxis.Expert opinion: Reviewed studies provide biological plausibility and preliminary clinical evidence pointing to the pathogenic role of CMV in post-transplant atherogenesis. However, no definitive recommendations can be made regarding the use of antiviral prophylaxis to prevent post-transplant AE, since existing evidence is mainly founded on inadequately powered post hoc analysis. Well-designed observational studies should clarify the differential impact of prophylactic or preemptive approaches on the occurrence of CMV-associated post-transplant AE among KT recipients.

Artery Wall Assessment Helps Predict Kidney Transplant Outcome

Background

Kidney transplant recipients have high cardiovascular risk, and vascular inflammation may play an important role. We explored whether the inflammatory state in the vessel wall was related to carotid intima-media thickness (c-IMT) and patient survival following kidney transplantation.

Methods

In this prospective observational cohort study we measured c-IMT and expression of proinflammatory cytokines and adhesion molecules in the inferior epigastric artery in 115 kidney transplant candidates. Another c-IMT measurement was done 1-year post-transplantation in 107. By stepwise multiple regression analysis we explored factors associated with baseline c-IMT and their changes over time. Multivariate Cox regression analysis was constructed to identify risk factors for mortality.

Results

A worse cardiovascular profile (older age, smoker, diabetic, carotid plaque, systolic blood pressure and vascular calcification) and higher VCAM-1 levels were found in patients in the highest baseline c-IMT tertile, who also had a worse survival. Factors independently related to baseline c-IMT were age (β=0.369, P<0.0001), fasting glucose (β=0.168, P=0.045), smoking (β=0.228, P=0.003) and VCAM-1 levels (β=0.244, P=0.002). Independent factors associated with c-IMT measurement 1-year post-transplantation were baseline c-IMT (β=-0.677, P<0.0001), post-transplant diabetes (β=0.225, P=0.003) and triglycerides (β=0.302, P=0.023). Vascular VCAM-1 levels were associated with increased risk of mortality in bivariate and multivariate Cox regression. Notably, nearly 50% of patients showed an increase or maintenance of high c-IMT 1 year post-transplantation and these patients experienced a higher mortality (13 versus 3.5%; P=0.021).

Conclusion

A worse cardiovascular profile and a higher vascular VCAM-1 protein levels at time of KT are related to subclinical atheromatosis. This could lead to a higher post-transplant mortality. Pre-transplant c IMT, post-transplant diabetes and triglycerides at 1-year post-transplantation may condition a high c-IMT measurement post-transplantation, which may decrease patient survival.

Hematology and plasma biochemistry in rats fed with diets enriched with fatty fishes from Amazon region

OBJECTIVE: Rats fed diets enriched with fatty fish from the Amazon region had Hematology and plasma biochemistry analyzed. METHODS: Forty Wistar rats were divided into four groups: control group fed a standard diet; mapará group fed a diet enriched with Hypophthalmus edentatus; matrinxã group fed a diet enriched with Brycon spp.; and tambaqui group fed a diet enriched with Colossoma macropomum. After thirty days the rats had an red blood count and plasma biochemistry. RESULTS: Hematocrit and hemoglobin levels were higher in rats fed tambaqui and matrinxã than in those fed the standard diet of mapará. However, mapará increased cholesterol, especially low-density lipoprotein cholesterol and high-density lipoprotein cholesterol. All fish-enriched diets reduced triacylglycerols. CONCLUSION: Diets enriched with fatty fish from the Amazon region reduce triacylglycerol and increase high-density lipoprotein cholesterol, especially the diet enriched with tambaqui. Tambaqui and matrinxã affected hematocrit and hemoglobin levels, but not mapará. Further research is needed to determine the benefits of diets enriched with fatty fish from the Amazon region.

The relationships between serum sTWEAK, FGF-23 levels, and carotid atherosclerosis in renal transplant patients

BACKGROUND

Cardiovascular disease is the main cause of mortality after renal transplantation. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) and fibroblast growth factor-23 (FGF-23) are two novel molecules that have been associated with atherosclerosis in different populations. In this cross-sectional study, we investigated the associations between sTWEAK, FGF-23, and carotid artery intima-media thickness (CA-IMT) in renal transplant patients.

METHODS

A total of 117 renal transplant patients were studied. CA-IMT was determined by B-mode Doppler ultrasonography. Serum sTWEAK and FGF-23 were measured by a commercially available enzyme-linked immunosorbent assay (ELISA).

RESULTS

Mean age was 39.6 ± 9.6 years and 51% of the patients were male. Mean sTWEAK level was 595 ± 225 pg/mL (158-1140), FGF-23 level was 92 ± 123 RU/mL (9.6-1006), and CA-IMT level was 0.62 ± 0.11 mm (0.40-0.98). sTWEAK level was positively correlated with CA-IMT. There was no association between sTWEAK and FGF-23 levels. FGF-23 was also associated with CA-IMT. In adjusted models using linear regression analysis, only age and serum TWEAK levels were predictors for CA-IMT.

CONCLUSION

There is a positive correlation between CA-IMT and sTWEAK, but not with FGF-23 levels in renal transplant patients.

Evaluation of arterial stiffness after successful renal transplantation using brachial-ankle pulse wave velocity

BACKGROUND

Cardiovascular disease remains a main cause of mortality in renal transplant recipients. Determination of aortic stiffness with pulse wave velocity (PWV) is considered a strong predictor of cardiovascular risk. We investigated arterial stiffness with brachial-ankle pulse wave velocity (baPWV) after successful renal transplantation.

METHODS

We studied 197 patients (mean age = 53.2 ± 10.8 years) who underwent successful renal transplantation. baPWV was evaluated with a noninvasive automatic Omron Colin device. During follow-up (mean = 183.8 ± 108.9 months), we investigated parameters of sex, age, body mass index, duration before (dialysis) and after transplantation, and cardiovascular risk factors (hypertension and diabetes). In all subjects, fasting concentrations of serum creatinine, non-(HDL) high-density lipoprotein-cholesterol (total cholesterol minus HDL-cholesterol), low-density lipoprotein-cholesterol, and triglyceride were also compared with those at enrollment.

RESULTS

Mean baPWV levels were 1519 ± 329 cm/s in our renal transplant recipients. baPWV increased independent of age, duration of dialysis before transplantation, and cardiovascular risk factors. Serum creatinine and dilation did not show any significant correlations to baPWV.

CONCLUSION

In renal transplant recipients, baPWV may be more influenced by past clinical history before transplantation than by current condition. Noninvasive assessment of arterial stiffness with baPWV may be a useful and convenient indicator of cardiovascular disease after renal transplantation.

Intima-media thickness measurements in children with cardiovascular risk factors

Measuring intima-media thickness (IMT) is now a standard diagnostic procedure in assessing cardiovascular risk and hypertensive target-organ damage (TOD) in adults. There is also an increasing number of pediatric publications evaluating IMT in children from high-risk groups, such as those with arterial hypertension, diabetes, chronic kidney disease, obesity, dyslipidemia, and homocystinurias. It has been shown that carotid IMT is strongly related with other markers of TOD in children with arterial hypertension and with metabolic cardiovascular risk factors. In children with coarctation of the aorta, carotid IMT correlated both with blood pressure and even with mild residual aortic gradient. On the other hand, studies in children with high cardiovascular risk have shown that normalization of blood pressure and metabolic abnormalities led to regression of arterial changes and decrease of IMT. Although not yet accepted as standard pediatric procedure, IMT measurement is emerging as a promising method of assessing TOD and cardiovascular risk and monitoring treatment efficacy. From a practical point of view, clinical utility of IMT measurements seems to be similar to use of echocardiography in assessing left ventricular mass. However, IMT measurements in children and adolescents should be standardized to avoid bias caused by the use of different measurement methods.

Arterial changes in children undergoing renal transplantation

INTRODUCTION

Pathological changes of large arterial walls and the heart have been described in patients with chronic renal failure. The aim of the study was to verify the incidence of arterial changes among our series of pediatric patients with end-stage renal disease undergoing transplantation.

PATIENTS AND METHODS

From January 2004 to December 2006, 26 patients (15 boys and 11 girls) of overall mean age of 13.12 years (range=3-27 years) underwent renal transplantation in our department. The pretransplant dialysis treatment was peritoneal in eight and hemodialysis in 18 cases. All patients were divided in two groups according to primary renal disease: group A were 18 patients with congenital urinary malformations; and group B, eight patients with acquired glomerular diseases. In each case, a sample of artery from both donor (aortic patch of kidney) and recipient (iliac patch of graft allocation) was obtained during renal transplantation. The donors were considered to be the control group.

RESULTS

Light microscopy showed pathological changes in 12/26 recipient arteries: nine showed light fragmentation of the internal elastic lamina; two, more severe fragmentations; and one, fragmentation of the internal elastic lamina associated with mucopolysaccharide deposits. Pathological changes were more evident in group A than B, but the difference was not significant (P> .05). Among the donor group, 11 patients showed light fragmentation of the internal elastic lamina, but there was no significant difference with the recipients (P> .05).

CONCLUSIONS

Among our group of patients, we observed only slight modifications of the arterial wall. These changes were nonspecific, similar to those in a control group of donors matched for age. A possible explanation of these findings may depend on the short time of dialysis before transplantation.

Evaluation of aortic stiffness in children with chronic renal failure

The measurement of aortic stiffness (As) [aortic strain (S), pressure strain elastic modulus (Ep) and pressure strain normalized by diastolic pressure (Ep*)] is suggested as an excellent marker of subclinical arterial sclerosis. We aimed to investigate the presence of As and to determine the relationship between As and some risk factors in children with chronic renal failure (CRF). Twenty-six pre-dialysis (PreD) [female/male (F/M) 7/19] patients and 23 chronic peritoneal dialysis (CPD) (F/M 13/10) patients were assessed. Twenty-nine healthy children were selected as a control group (F/M 14/15). We determined anemia, abnormal calcium/phosphate metabolism, hypertension, diastolic dysfunction, increased left ventricular mass (LVM), hypertriglyceridemia, increased stiffness (Ep, Ep*), and decreased strain (S) in the CRF (PreD and CPD) group compared with the controls (P < 0.05). Presence of renal disease, LVM and usage of angiotensin-converting enzyme inhibitor (ACE-I) in all groups; female gender, duration of disease and the usage of anti-hypertensive drug therapy in CRF patients; and LVM and LVM index in healthy children were found to be independent predictors for aortic stiffness and/or strain. In conclusion, CRF is associated with significant arterial functional abnormalities in uremic children and not controlled by dialysis treatment. These results suggest that, even in young children, uremia has a profound impact on arterial function.

Increased arterial stiffness in children on haemodialysis

BACKGROUND

Measures of aortic stiffness--aortic pulse wave velocity (PWV) and augmentation index (AIx)--have been shown to be powerful predictors of survival in adult haemodialysis (HD) patients. Very few data have been reported regarding arterial stiffness in paediatric renal populations.

METHODS

PWV and aortic AIx were determined from contour analysis of arterial waveforms recorded by applanation tonometry using a SphygmoCor device in 14 children on HD (age = 14.1 years) and in 15 age, height matched children controls.

RESULTS

Pre-HD AIx (29.7 +/- 15.4%) and PWV (6.6 +/- 1.0 m/s) were significantly higher compared with children controls (8.3 +/- 8.0% and 5.4 +/- 0.6 m/s, respectively, P < 0.0001). The only significant difference between normal and HD children was BP level: 103/61 vs 114/72 mmHg, P < 0.05. In children of HD patients, a multiple linear regression model including BP, age, height, weight, Ca and P levels as independent variables accounted for 57% of the variability in AIx. Dialysis had no impact on AIx (post-HD: 28.5 +/- 12.7%) or on PWV (post-HD: 6.7 +/- 0.8 m/s).

CONCLUSIONS

We show, in this first-ever report of increased arterial stiffness in children on dialysis, that end-stage renal disease is associated with abnormalities in arterial wall elastic properties, comparable with adult levels, even in childhood. Most importantly, the absence of a discernible amelioration with dialysis implies that purely structural and not functional alterations lie behind the increased arterial stiffness.