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Background: The arteriovenous (AV) access function of hemodialysis (HD) patients can be impaired by afferent artery stiffness due to preexisting microcalcification and by venous stenosis secondary to neointimal hyperplasia in whose development participates an upregulated local inflammatory process. Fetuin-A is a circulating potent inhibitor of vascular calcification and plays an important anti-inflammatory role. The aims of this prospective study were to investigate the relationship between baseline serum fetuin-A levels and: blood flow (QA) values at baseline, AV access failure (thrombosis or intervention for stenosis) during follow-up and primary unassisted AV access patency. Methods: We measured baseline serum fetuin-A levels and QA values of the AV access in 64 HD patients under routine QA surveillance for stenosis. Patients were classified into tertiles according to their baseline fetuin-A levels (g/L): 1.20 (tertile-3). Results: Fetuin-A was positively correlated with QA (Spearman coefficient = 0.311, p = 0.012). Fourteen patients (21.9%) underwent AV access failure and they had lower fetuin-A (0.59 ± 0.32 g/L) and lower QA (739.4 ± 438.8 mL/min) values at baseline compared with the remaining patients (1.05 ± 0.65 g/L and 1273.0 ± 596.3 mL/min, respectively) ( p = 0.027 and p 2 = 4.68, p = 0.030, log-rank test). Conclusion: If our results are confirmed in further studies, fetuin-A could be used as a circulating biomarker to identify HD patients at greater risk for AV access dysfunction, who would benefit from much closer dialysis access surveillance.

Background We prospectively analyzed the effect of preexisting structural changes of the radial artery (RA) wall by histological examination on the wrist radiocephalic fistula (RCF) outcomes. Methods During RCF creation, one segment of the RA wall was collected and its histomorphometric analysis was performed. The RCF function was evaluated by measuring blood flow rate. Results At the end of follow-up, 75.7% of the thirty-seven patients enrolled were performing hemodialysis by using their successful RCF and 24.3% of them showed early RCF failure. Compared to patients with a healthy RA, the RCF of those with medial RA microcalcification reached up a lower flow and a shorter primary patency (P=0.005 and P=0.040, respectively). The RA microcalcification was predictive of the RCF function (coefficient -614.9, 95% CI: -994.7 to -235.1, P=0.003). Compared to patients with successful RCF, those with failed RCF had a greater frequency of weak RCF thrill after releasing the clamps (P=0.045). Dependence on hemodialysis during RCF placement was predictive of its early failure (OR: 23.2, 95% CI: 1.76 to 306.9, P=0.017). Both having at least one cardiovascular comorbidity (HR 4.30, 95% CI: 1.29 to 14.39, P=0.018) and a thicker media layer of the RA (HR 1.60, 95% CI: 1.87 to 2.15, P=0.002) were predictive of primary RCF patency. Conclusions The function and survival of the successful RCF were related to preoperative RA abnormalities such as microcalcification and media layer thickness. Both dependence on hemodialysis during RCF placement and an attenuated RCF thrill were associated with early RCF failure.

To report experience over five years of vascular access (VA) stenosis surveillance.We prospectively monitored the blood flow rate (QA) of 145 VA in 131 ESRD (age 62.6 ±13.5 y) patients (pts). QA measurement: within the first hour of the hemodialysis (HD) session by the Delta-H method using the Crit Line III Monitor. All VA with baseline QA700 mL/min or decreased20% from baseline over time met the positive evaluation (PE) criteria and were referred for angiography (AG) plus elective intervention if stenosis = 50%.We found 54 cases of PE in 47 VA; the AG was performed in 87% (47/54) cases of PE and most of them (43/47, positive predictive value: 91.5%) showed significant stenosis (mean degree 80.5 ±12.9%). Mean QA increased from 554.7±107.6 mL/min to 977.9 ± 359.9 mL/min just before versus after preventive intervention (P.001). Without difference when comparing the highest QA reported before stenosis development (889.8 ± 409.5 mL/min) and the QA recorded just post-intervention (P=.18). Kt/V index: improved from 1.43 ± 0.22 to 1.49 ± 0.21 just before versus after intervention (P=.006).1) The Delta-H technique is an accurate method for early diagnosis of VA stenosis and is useful in monitoring the hemodynamic effect of elective VA treatment. 2) After preventive intervention for stenosis, functional VA status is restored and HD delivery is improved.

Purpose To evaluate the functional effects of preventive vascular access (VA) intervention through periodic blood flow (QA) measurements during hemodialysis (HD) by the delta-H method. Methods We prospectively monitored the blood flow rate (QA) of 100 VA (arteriovenous fistula (AVF) 81% or AV graft (AVG) 19%; mean VA duration 24.6 ± 42.3 months) during HD in 89 end-stage renal disease patients (mean age 62.7 ± 13.6 yrs; mean time on HD 30.9 ± 43.9 months; 18% with diabetes) over a 3-yr period. QA was measured at least every 4 months by the delta-H method (Yarar (6)) using the Crit Line III Monitor (overall mean QA 1247.6 ± 519.7 ml/min). The mean arterial pressure (MAP) and Kt/V index were measured simultaneously with QA. Thirty-eight VA (38%) met the positive evaluation criteria (absolute QA A decreased >20% from baseline 50%). Most cases with positive evaluation underwent angiography (36/38, 95%) and had stenosis ≥50% (34/36, 94%). Of VA with significant stenosis, 17 (17/34, 50%) VA (AVF 76.5%, AVG 23.5%; mean VA duration 12.5 ± 22.4 months, mean percentage of VA stenosis 75.8%) in 15 patients (mean age 68.4 ± 9.8 yrs; mean time on HD 14.2 ± 18.2 months; 33.3% with diabetes) underwent corrective intervention by angioplasty, 35.3% (6/17), and revision surgery, 64.7% (11/17). Results Short-term results: Elective intervention was successful in 88% of treated VA (15/17). Mean QA increased from 563.8 ± 115.4 ml/min just before intervention (QA pre) to 975.7 ± 351.8 ml/min just after intervention (QA post) (mean ΔQA = 411.8 ± 290.1 ml/min) (p < 0.001). We found a significant difference between the overall mean QA before (689.6 ± 227.0 ml/min) vs after intervention (965.9 ± 396.8 ml/min) (p = 0.011). No difference was found when the highest recorded mean QA before intervention (877.7 ± 415.4 ml/min) and mean QA post were compared (p = 0.25). Mean MAP did not change after intervention (91.5 ± 12.5 vs 92.7 ± 14.2 mmHg, p = 0.46). Mean Kt/V index improved from 1.44 ± 0.24 just before intervention to 1.49 ± 0.23 just after intervention without any change in dialyzer type or HD duration (p = 0.025). Mean ΔQA was similar for diabetic patients vs non-diabetic patients (p = 0.34), for younger patients (age < 65 yrs) vs older patients (age ≥65 yrs) (p = 0.64) and for AVF vs AVG (p = 0.39). We found a positive correlation between mean ΔQA and mean QA post (r = 0.95, p < 0.001) or between mean ΔQA and overall mean QA after intervention (r = 0.77, p < 0.001). Long-term results Prevalence of VA thrombosis during the follow-up period (354.4 ± 293.1 days): 17.6% (3/17). Five (29.4%) treated VA showed restenosis and two of them (40%) underwent reintervention by surgery. Mean restenosis period and mean decrease in QA were 232.6 ± 74.1 days and 2.8 ± 0.6 ml/min/day, respectively. No significant correlation was found between mean ΔQA or QA pre and mean restenosis period or decrease in QA (p = ns). Conclusions 1) Monitoring QA by the delta-H method is useful in assessing the hemodynamic response to elective VA intervention. 2) Mean QA post was similar to the highest recorded mean QA before intervention. 3) Mean ΔQA was related to mean QA post and overall mean QA after intervention. 4) The HD effectiveness (Kt/V index) improved after intervention.