Jovan Popovic

Impact of Vascular Calcifications on Arteriovenous Fistula Survival in Hemodialysis Patients: A Five-Year Follow-Up

Background/Aims: Vascular calcifications are frequently found among dialysis patients, and the calcification process may influence the patients outcome. The aim of the present study was to determine the role that vascular calcifications may have on autologous arteriovenous fistula (AVF) survival. Methods: This study included 90 patients (49 males, mean age 62 ± 11) with a native AVF treated by chronic hemodialysis (HD) for more than one year. The overall vascular calcification scores ranged from 0-11 (Adragao score + vascular access calcification score); patients were categorized into mild (score 0-3; n = 36), moderate (score 4-7; n = 24) and severe (score 8-11; n = 30) calcification groups. AVF survival was then followed for 5 years after calcification measurement or until the patients death/transplantation. Results: Patients with more pronounced vascular calcifications were more frequently diabetic and male. Multiple linear regression analysis showed a significant relationship between calcification score and male gender, diabetes mellitus, previous duration of AVF, low dialysis flow rate and intact parathormone (iPTH) values. After multivariate adjustment for basal differences, Cox proportional analysis revealed a graded impact of calcification scores on AVF failure: moderate scores (were associated with a hazard rate (HR) of 3.82 (95% confidence interval (CI) 1.10-13.23) and severe scores with an HR of 4.65 (CI 0.97-22.38). Conclusion: Vascular calcifications are associated with worse survival of native arteriovenous hemodialysis fistulas.

Arteriovenous Fistula Aneurysm in Patients on Regular Hemodialysis: Prevalence and Risk Factors

Background/Aims: Compared to all other complications, literature data about vascular access aneurysm (VAA) are the scarcest. The aim of this cross-sectional study was to evaluate the prevalence of arteriovenous fistula (AVF) aneurysms and to confirm the risk factors for their appearance. Methods: The presence, number and morphological characteristics of AVF aneurysms were confirmed, and according to the score of AVF aneurysm (the sum of the length and width in cm), patients were classified into group 1 (score ≤12) and group 2 (score >12). Analysis included the last data from the medical records including vascular calcifications score. Results: Out of 181 patients, 150 with native fistula were included in this study. Aneurysmatic changes were detected in 90 (60%) patients, and the majority had two or more aneurysms. VAA were more frequent in patients with adult polycystic kidney disease (ADPKD) than in other diagnostic categories. By using forward stepwise logistic regression, we confirmed that patients on high-flux hemodialysis (HD) had 5.3-fold higher risk, and patients with diabetes mellitus had 5.8-fold less risk for developing AVF aneurysm. While vascular calcification score did not influence the incidence of VAA, higher PWV had significant negative influence on formation of AVF aneurysm (OR 1.25, 95% CI 1.003-1.56, p = 0.047). By ROC curve analysis, it was determined that patients who were longer than 5.7 years on HD had greater risk for developing VAA (area = 0.741, p = 0.000). Conclusion: This single-center study confirmed the very high prevalence of VAA (60%). Aneurysms were more frequent in patients with ADPKD and in those who had longer dialysis vintage on high-flux membranes with higher blood flow rate.

Mycophenolate Mofetil in High-Risk Patients with Primary Glomerulonephritis: Results of a 1-Year Prospective Study

Background/Aims: Glucocorticoids and classic immunosuppressive drugs can improve disease activity in primary glomerulonephritis (GN). However, these drugs have serious toxicity and patients frequently experience inadequate response or relapse, so there is a need for alternative agents. This multicenter uncontrolled study analyzed the efficacy and safety of mycophenolate mofetil (MMF) in high-risk patients with primary GN. Methods: A total of 51 patients with biopsy-proven membranous (n = 12), membranoproliferative (n = 15), mesangioproliferative (n = 10), focal segmental glomerulosclerosis (n = 13) and minimal change disease (n = 1) received MMF with low-dose corticosteroids for 1 year. The primary outcome included the number of patients with complete/partial remission. Results: Proteinuria significantly decreased, from its median value of 4.9 g/day (IQR 2.9–8.4) to 1.28 g/day (IQR 0.5–2.9), p < 0.001. The urine protein/creatinine ratio significantly improved, from a median of 3.72 (IQR 2.13–6.48) to 0.84 (IQR 0.42–2.01), p < 0.001. The mean area under the curve for proteinuria significantly decreased, from 4.99 ± 3.46 to 2.16 ± 2.46, between the first (visits 1–2) and last (vists 4–5) treatment periods (p < 0.001). The change was similar for every type of GN, without difference between groups. eGFR slightly increased (62.1 ± 31.8 to 65.3 ± 31.8 ml/min, p = n.s.) and ESR, total proteins, albumins, total- and HDL-cholesterol parameters improved significantly. Systolic, diastolic and mean blood pressure decreased (p < 0.02 for systolic blood pressure). The age of patients was the only independent predictor of complete or partial remission. Conclusion: MMF proved to be efficient in 70% of high-risk patients with primary GN, who reached either complete or partial remission without safety concern after 12 months of treatment. Favorable effects of MMF therapy have to be confirmed in the long term and particularly after discontinuation of the drug.

Polymorphism of angiotensin converting enzyme in hemodialysis patients--association with cardiovascular morbidity.

INTRODUCTION Cardiovascular morbidity and mortality are the major concern in dialysis patients and many risk factors are thought to be involved in its pathogenesis. Apart from traditional and non-traditional risk factors, the genetic susceptibility may be of importance, including renin-angiotensin system gene polymorphism. The aim of this study was to analyse renin-angiotensin system polymorphism in our group of hemodialysis patients and to correlate the findings with cardiovascular morbidity. MATERIAL AND METHODS The study included 196 patients on regular hemodialysis on polysulphone membrane three times per week for more than six months. Genetic analysis was performed by using polymerase chain reaction-restriction fragment length polymorphism method. RESULTS Out of 196 patients, 55% had I/D genotype, 35% had D/D and 10% had I/I, including angiotensin-converting enzyme polymorphism. It was shown that the patients with D allele genotype developed a significantly higher incidence of left ventricular hypertrophy and peripheral vascular disease. The angiotensin-converting enzyme polymorphism showed a significant association with the incidence of cerebrovascular accident and hyperlipoproteinemia in our group of hemodialysis patients. CONCLUSION The angiotensin-converting enzyme gene polymorphism is associated with the development of cerebrovascular accidents and hyperlipoproteinemia. Allele D of this gene increases the risk for the development of left ventricular hypertrophy and peripheral vascular disease significantly in hemodialysis patients. A longer follow-up is needed to make the definitive conclusion about the influence of angiotensin-converting enzyme polymorphism on cardiovascular morbidity and its importance in everyday clinical practice.

The 5A Allele of the MMP3-Gene Promoter Polymorphism Is a Risk Factor for Poor Outcome of Hemodialysis Patients

Cardiovascular morbidity is the leading cause of death in dialysis patients and many risk factors have been involved in its pathogenesis. Genetic susceptibility may be of importance including polymorphism for matrix metalloproteinase 3 (MMP3), which is an enzyme that catalyzes the degradation of collagen, proteoglycans, fibronectin, laminine and elastin. The MMP3 gene promoter contains an insertion/deletion polymorphism characterised by an array of 5 or 6 adenosine residues (5A/6A) at -1612 position. Literature data show that the 5A or 6A allele of the MMP3 gene shows different risk for cardiovascular and overall outcome in general population. The aim was to analyze the -1612 5A/6A promoter polymorphism in a group of hemodialysis patients and to correlate the findings with cardiovascular morbidity and 7-year all-cause and cardiovascular mortality. This study included 196 patients on hemodialysis for longer than six months at University Medical Center Zvezdara. The leading causes of end stage renal disease were hypertension and diabetes mellitus. Venous blood was collected on midweek dialysis session and genotype analysis was performed by using polymerase chain reaction-restriction fragment length polymorphism method. Among the 198 hemodialysis patients, there were 142 (72%) 5A/6A heterozygotes, 12 (6%) 5A/5A homozygotes, and 44 (22%) 6A/6A homozygotes. These data are consistent with Hardy-Weinberg equilibrium. After 7-year follow-up, the 5A homozygotes showed the lowest all-cause and cardiovascular survival, while the 6A homozygotes showed the highest cardiovascular survival. The 5A allele of the MMP3-gene promoter polymorphism is a potential risk factor in the poor outcome of hemodialysis patients.