Superficialization Methods of Arteriovenous Fistula in Obese Patients: A Review of the Literature.

BACKGROUND: The creation of an arteriovenous fistula in obese patients with end-stage-renal-disease, might not lead to a successful hemodialysis session, partly due to excess adipose tissue overlapping the enlarged vein. This review summarizes the available evidence on superficialization methods in studies dealing with obese patients. METHODS: An English-language literature search was undertaken in the MEDLINE/SCOPUS databases looking for publications that described procedures of salvaging autologous arteriovenous access in upper extremities of obese patients. Perioperative outcomes including technical and clinical success, mean vein depth reduction, wound complications and patency rates were compared within all identified techniques. RESULTS: We identified 12 prospective and 8 retrospective studies. A total of 1149 patients with a mean age 57.2 (range: 49-68) years and a mean BMI 35.8 (range: 28.2-40.8) kg/m2 underwent mainly radial-cephalic and brachial-cephalic arteriovenous fistula superficialization procedures [transposition, 54%; elevation, 11.1%; lipectomy, 26.1%; liposuction, 2.4%; implantation of a venous window needle guide device, 6.4%]. Technical success was similar between all methods (≥96%). However, successful cannulation was lower after liposuction and elevation (81.5% and 78.1% respectively). Transposition achieved lower mean vein depth reduction and clinical success when compared with lipectomy (4.9 mm vs. 8.8 mm and 90% vs. 92.7% respectively). Transposition and liposuction had the lowest and highest complication rate respectively (1.6% vs. 40.8%). Primary and secondary patency rates were lower with liposuction (51.8% and 76.6% respectively), while lipectomy and elevation achieved the highest primary patency rates (68.3% and 71.6% respectively) at 12 months. CONCLUSIONS: In obese patients, all superficialisation techniques report high technical success rates. Although limited by the design of individual published studies and lack of a standard for reporting outcomes, these results lead to satisfactory postoperative and early outcomes. In aggregate, lipectomy and transposition are more clinically effective and more durable procedures.

Correlation of pre-existing radial artery macrocalcifications with late patency of primary radiocephalic fistulas in diabetic hemodialysis patients.

OBJECTIVE: The aim of this study was to evaluate the impact of pre-existing radial artery macrocalcification (Mönckeberg type of arteriosclerosis) on patency rates of radiocephalic fistulas (RCFs) in diabetic end-stage renal disease (ESRD) patients undergoing hemodialysis. METHODS: In this observational prospective study, the long-term patency rates (primary outcome measures) of RCFs in ESRD diabetics who had Mönckeberg radial (±brachial) artery disease (calcified [C] group) were compared with those obtained in ESRD diabetics who had healthy, noncalcified vessels before RCF construction (healthy [H] group). Vessel calcification was assessed by plain two-dimensional radiography. For inclusion in the C-group, uniform linear railroad track-type macrocalcifications of at least 6 cm in length, in the medial wall of the radial artery ipsilateral to RCF creation, were required. Patients were included in the H-group if the radial artery ipsilateral to the RCF creation was free of any macrocalcification, of either intima or media type. Any intimal-like plaque with irregular and patchy distribution was an exclusion criterion for both groups. Patients in both groups also were required to have suitable upper limb vascular anatomy on the basis of ultrasound imaging before RCF creation (cephalic vein of minimum diameter of 1.6 mm, without stenosis or thrombosis in all outflow areas, and radial artery of minimum diameter of 1.5 mm, without proximal hemodynamically significant stenosis). Secondary outcome measures included all-cause mortality. Kaplan-Meier statistics were used for comparison between groups. RESULTS: The arm radiograph at the site of possible fistula construction showed abnormality in 39 patients (C-group, 47 RCFs), whereas 33 patients had noncalcified ("healthy") vascular anatomy (H-group, 40 RCFs). Mean duration of the diabetic disease at the time of RCF creation was 8.9 ± 5.6 years (range, 2-25 years) for the H-group and 14 ± 9.9 years (range, 1-40 years) for the C-group (P = .018). The mean follow-up period for H-group and C-group was 51.9 ± 35.9 months (range, 0.1-126 months) and 26.1 ± 31.6 months (range, 0.1-144 months), respectively (P = .0006). Forty-four patients died during the follow-up period. Primary patency rates at 12, 24, 36, and 48 months for C-group vs H-group were 50.2% vs 80%, 36.5% vs 72.3%, 32.4% vs 67.9%, and 29.1% vs 59.3% (P = .0019). Respective values for secondary patency rates were 52.4% vs 87.5%, 40.9% vs 82.4%, 36.6% vs 78.1%, and 33.2% vs 72.8% (P = .00064). Patient survival rates at 24 and 48 months were 56.1% and 46.4% for C-group and 92.4% and 67.4% for H-group, respectively (P = .05). CONCLUSIONS: ESRD diabetics with radial artery Mönckeberg calcifications receiving RCFs had worse late clinical outcomes compared with ESRD diabetics with healthy distal arm vessels receiving the same access. The long-term benefit of RCFs may be lost in diabetics with extensively calcified vessels, and preferably the brachial artery should be used instead.

D-dimer, factor VIII and von Willebrand factor predict a non-dipping pattern of blood pressure in hypertensive patients.

AIM: The aim of this study is to assess whether the haemostatic markers D-dimer, factor VIII (FVIII) and von Willebrand factor (VWF) are predictive of non-dipping status in treated hypertensive patients; so, as easy available laboratory data can predict non-dipping pattern and help with the selection of the patients whom circadian blood pressure should be re-examined. PATIENTS AND METHODS: Forty treated hypertensive patients with essential hypertension were included in the study. Twenty-four-hour ambulatory blood pressure monitoring was performed in all patients. Daytime and nocturnal average systolic, diastolic and mean blood pressures were calculated. Patients were characterised as "non-dippers" on the basis of a less than 10 % decline in nocturnal blood pressure (BP); either systolic or diastolic or mean (MAP). D-dimer as marker of fibrinolytic function, FVIII activity and VWF antigen as marker of endothelial dysfunction were measured on plasma. The predictive efficiency was analysed by receiver operating characteristic (ROC) curves. Youden index was used for the estimation of the cut-off points and the associated values for sensitivity and 1-specificity. RESULTS: Plasma levels of D-dimer, FVIII and VWF were significantly higher in non-dippers as compared with dippers, irrespective of the classification used (BP index); all P < 0.05. The ROC curves indicated a good diagnostic efficiency for D-dimer (AUC(ROC) = 0.697, 0.715 and 0.774), FVIII (AUC(ROC) = 0.714, 0.692 and 0.755) and VWF (AUC(ROC) = 0.706, 0.740 and 0.708) in distinguishing non-dipping pattern (systolic, diastolic or mean) in the study population; all P < 0.05. Among the three haemostatic markers, D-dimer presents the most satisfactory sensitivity/1-specificity for the differentiation of non-dippers, with a cut-off point >168 ng/ml (sensitivity/1-specificity for systolic BP non-dippers of 0.789/0.381, for diastolic BP non-dippers 0.923/0.444 and for MAP non-dippers 0.875/0.375). CONCLUSION: In conclusion, D-dimer has a good predictive value for non-dipping pattern and the decision for the 24-h ambulatory blood pressure re-monitoring among dippers could rely on its values.

Changes in haemostatic and platelet activation markers in non-dipper hypertensive patients.

BACKGROUND: Non-dipper hypertensive patients are at increased risk for cardiovascular disease. Coagulation and fibrinolysis activation factors are considered as risk factors for cardiovascular disease. The aim of this study was to examine the relationship between the haemostatic and platelet activation markers and the non-dipping pattern in treated hypertensive patients. PATIENTS AND METHODS: Seventy-one treated hypertensive patients (53 with essential and 18 with secondary hypertension, due to chronic kidney disease-stage 4), aged 33 to 81 years (30 men), were classified as dippers and non-dippers, according to the presence or absence, respectively, of a decline of nocturnal average systolic blood pressure (BP) by more than 10% of the diurnal BP (non-dipping pattern) on 24-hour ambulatory BP monitoring. Plasma levels of factors VIII and IX, fibrinogen, prothrombin fragment 1 + 2, thrombin-antithrombin complex, protein C, plasmin-alpha-2 antiplasmin complex, D-dimer and platelet factor 4 were measured in all patients. RESULTS: Thirty-seven patients were classified as dippers and 34 as non-dippers. The percentages of patients with essential and with secondary hypertension were similar in the dippers and in the non-dippers groups (both P = 0.754). Multivariate analysis of variance showed statistically significant differences in all measured variables between dippers and non-dippers (P = 0.043). Plasma levels of factors VIII and IX, fibrinogen, prothrombin fragment 1 + 2, protein C, plasmin-alpha-2-antiplasmin complex, and D-dimers were significantly higher in non-dippers when compared to dippers (P < 0.05 for all). In contrast, there were no significant differences in plasma levels of thrombin-antithrombin complex (P = 0.955) and platelet factor 4 (P = 0.431) between the two groups. CONCLUSION: This study provides evidence that non-dipper treated hypertensive patients exhibit alterations in haemostasis, which may affect their cardiovascular risk.

A hybrid approach to salvage a failing long-standing autogenous aneurysmal fistula in a hemodialysis patient.

Very few studies have addressed the repair of autogenous and prosthetic-related false arteriovenous access (AVA) aneurysms in hemodialysis patients. Surgical management of complicated AVA-related aneurysms remains the gold standard method although covered stents have recently been introduced for the exclusion of such aneurysms, offering a minimally invasive therapy. In this paper, we describe a combination of open and endovascular repair for treating an anastomotic and a puncture-site aneurysm to salvage a failing long-standing autogenous radial-cephalic fistula in the wrist. Resection of the anastomotic aneurysm and reconstruction of the anastomosis proximally was initially performed. Via the first cm of the anastomosis, a Fluency® stent graft (SG) was inserted and it successfully excluded the mid-outflow vein false aneurysm. Such hybrid therapies may be the future of AVA revisions and this trend should not be overlooked by nephrologists and vascular surgeons.

Matrix metalloproteinase (MMP)-2 and MMP-9 in seminal plasma.

PURPOSE: To evaluate the latent and active forms of MMP-2 and MMP-9 in human semen samples and to investigate their association with semen parameters. METHODS: Basic semen analysis was performed in 82 semen samples. Seminal plasma was analyzed with gelatin zymography. RESULTS: Both latent and active forms of MMP-2 and MMP-9 were detected in human seminal plasma. The latent forms were the predominant ones. MMP-2 and MMP-9, either in latent or active forms, were not correlated with semen parameters. ProMMP-9 levels were higher in semen samples with abnormally low concentration (< or = 19 x 10(6)/ml) compared with semen samples with concentration > or = 50 x 10(6)/ml. CONCLUSION: MMP-2 and MMP-9 are both present in human semen. The latent forms of both MMPs are the predominant ones. ProMMP-9 is elevated in samples of low sperm concentration.

The Progression of Uremic Polyneuropathy in Patients on Hemodialysis and Hemofiltration: A Two-Year Study.

Uremic polyneuropathy is one of the major complications of long-term end-stage renal disease. In the present study, we performed an electrophysiologic evaluation in 17 patients having a mean age of 49 ± 11 years. The patients were divided into two groups according to dialysis method. Group A included 9 patients who were undergoing conventional hemodialysis (mean age, 44.2 ± 12.5 years; mean duration on dialysis, 21.7 ± 4.3 months); group B included 8 patients undergoing hemofiltration (mean age, 55.2 ± 5.2 years; mean duration on treatment, 27 ± 7.6 months). Measurements of the distal latency time of the sensory fibers (median, ulnar, and sural nerves), and measurements of the distal latency time and peripheral conduction velocity of the motor fibers (median and peroneal nerves) were performed. In addition, we recorded somatosensory evoked potentials after peripheral stimulation of the median and peroneal nerves. The electrophysiologic evaluations were repeated two times at intervals of 12 months. In group A, a statistically significant worsening of motor and sensory conductance in the upper and lower limbs was observed; in group B, a statistically significant improvement was found. These findings suggest that hemofiltration has a more beneficial effect on motor and sensory conductivity than does conventional hemodialysis.