Race and Sex Disparities in Outcomes of Dialysis Access Maintenance Interventions.

PURPOSE: To determine whether utilization and outcomes of dialysis access maintenance interventions vary by patient race or sex. MATERIALS AND METHODS: Data for this retrospective cohort study of first-time arteriovenous (AV) access recipients were drawn from a 5% sample of Medicare beneficiaries, containing claims from all clinical settings (2009-2014) in 2,693 patients who received their first AV fistula/graft in 2009. Maintenance interventions-angiography, angioplasty, thrombolysis, stent placement, and venous embolization-were identified by corresponding Current Procedural Terminology codes. Outcomes of primary patency (PP), postinterventional primary patency (PIPP), and postinterventional secondary patency (PISP) were calculated with utilization records. Associations between demographic data and patency times were evaluated by a multivariate survival approach, controlling for baseline differences in patient age, comorbid disease, type of dialysis access, and interventionist specialty. RESULTS: AV grafts (AVGs) were created with greater frequency in women (32% vs 23% in men; P < .001) and minority patients (39% in black, 32% in Hispanic, and 29% in Asian patients vs 21% in white patients; P < .001). Women were at greater hazards for loss of PP (hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.09-2.14) and PIPP (HR, 1.42; 95% CI, 1.01-2.00). Black patients were at greater hazards for loss of PP (HR, 1.37; 95% CI, 1.23-1.54) and PISP (HR, 1.29; 95% CI, 1.01-1.65). AVG creation predisposed patients to patency loss in all models (P < .001). CONCLUSIONS: Dialysis access patency rates are lower for women and black patients. More frequent primary AVG creation in women and minority patients additionally predisposes these patients to patency loss.

Role of Gene Polymorphisms/Haplotypes and Plasma Level of TGF-ß1 in Susceptibility to In-Stent Restenosis Following Coronary Implantation of Bare Metal Stent in Chinese Han Patients.

Transforming growth factor (TGF)-ß1 has been implicated in the pathogenesis of restenosis. However, the role of TGF-ß1 polymorphisms in development of in-stent restenosis (ISR) after coronary bare metal stent (BMS) implantation in Chinese Han population has not been reported to date. The aim of this study was to explore the association between TGF-ß1 gene polymorphisms (-509C/T and 869T/C) and its plasma level in Chinese Han patients with BMS-ISR.We investigated 419 patients after successful coronary stent placement. All patients were reexamined by angiography. Genotyping for the two TGF-ß1 gene polymorphisms was performed using polymerase chain reaction-restriction fragment length polymorphism analysis. Plasma TGF-ß1 levels were measured by enzyme-linked immunosorbent assay.Ninety-two patients (21.96%) developed ISR during the follow-up period. The multivariable analysis adjusted for potential confounders and it revealed that the C allele of TGF-ß1 869T/C polymorphism was linked to an increased risk of ISR in both additive (Per each C allele) and dominant (TC+CC versus TT) models with odds ratios (ORs) of 1.88 (95% confidence interval [CI]: 1.21-2.84, P = 0.008) and 2.52 (95% CI: 1.40-4.80, P = 0.005), respectively. In accord with this, C-dominant CC/CT genotype was linked to higher plasma TGF-ß1 level compared to TT genotype. One haplotype (TC) (-509T, +869C) was associated with an increased risk for ISR (OR = 1.48, 95% CI: 1.06-2.06, P = 0.010).The C allele of TGF-ß1 869T/C polymorphism, correlated with high plasma TGF-ß1 level, represented an independent risk factor for BMS-ISR in Chinese Han patients with coronary artery disease.

Clinical Course of Hemodialysis Access After Initial Endovascular Intervention for Stenosis in Asian Renal Failure Patients.

BACKGROUND: Arteriovenous fistula (AVF) and arteriovenous fistula graft (AVG) access for hemodialysis can develop stenosis, eventually leading to thrombosis and access failure. Prompt endovascular intervention can salvage the access but restenosis does occur. Clinical course, restenosis pattern, and risk factors associated with initial stenosis of AVFs/AVGs in Asian hemodialysis patients were studied. METHOD: A retrospective study was conducted (January 2009-June 2012) on consecutive patients with renal failure who developed the first-time stenosis in the vascular access and were managed with endovascular intervention. One hundred fourteen patients (54 AVFs and 60 AVGs) were studied, and all clinical outcomes were recorded until October 2013. RESULTS: The mean time from access creation to endovascular intervention for the first-time stenosis for patients with AVF and AVG was 23.5 (32.7 standard deviation [SD]) months and 12.5 (11.0) months, respectively. An average of 1.7 (range, 1-5) interventions were performed for AVFs, whereas 2.4 (range, 1-11) for AVGs ( P = .008). Upon conclusion of the study, 23 patients with AVF survived with functional index access, whereas 10 passed away with a functional original access. The remaining 21 patients with AVFs failed, requiring new access, tunneled catheter, or peritoneal dialysis. Of the 60 patients with AVG, 6 survived and 8 died with functional index access; 46 required new access or other forms of dialysis ( P = .000). Kaplan-Meier estimated that access patency and survival with functional access were significantly lower for AVGs than for AVFs after the first salvage intervention. Female patients had an increased risk of restenosis with both univariate ( P = .016) and multivariate ( P = .013) analysis. With univariate analysis ( P = .039), patients with hyperlipidemia had a higher risk of developing restenosis in the vascular access. CONCLUSION: The clinical course and prognosis of failing AVFs and AVGs are distinct. The information on access prognosis and stenosis recurrence patterns will be helpful for patient counseling and planning of follow-up intervals, after the first-time intervention for access stenosis.

Predictors of radio-cephalic arteriovenous fistulae patency in an Asian population.

PURPOSE: To identify predictors of arteriovenous fistula (AVF) patency in Asian patients with autogenous radio-cephalic arteriovenous fistula (RCAVF). METHODS: Retrospective review of 436 RCAVFs created between 2009 and 2013. Predictors of patency were identified with univariate and multivariate analysis. Kaplan-Meier survival analysis and log-rank test were used to calculate patency rates. RESULTS: Overall secondary patency rate was 72% at 12 months, 69% at 24 months, 58% at 36 months, 57% at 48 months, 56% at 60 months and 54% at 72 months. Univariate analysis showed that factors which predict for patency include male gender (p = 0.003), good diabetic control (p = 0.025), aspirin use (p = 0.031), pre-dialysis status (p = 0.037), radial artery diameter (p = 0.029) and non-calcified radial arteries (p = 0.002). Age (p = 0.866), cephalic vein diameter (p = 0.630) and surgeon grade (p = 0.472) did not predict for primary AVF failure. Multivariate analysis revealed the male gender to be an independent predictor for patency (odds ratio 1.99, p = 0.01). Subset analysis showed a significantly larger average radial artery diameter of 2.3 mm amongst males, as compared to 1.9 mm amongst females (p = 0.001) and no statistical difference in the average cephalic vein diameter. CONCLUSIONS: Within our Asian study population, 12-month patency rate of RCAVF is 72%, 69% at 24 months, 58% at 36 months, 57% at 48 months, 56% at 60 months and 54% at 72 months. Male gender is an independent predictor for RCAVF patency. In females or patients with calcified radial arteries, a more proximal AVF should be considered.

Interleukin-6 -634 C/G and -174 G/C polymorphisms in Korean patients undergoing hemodialysis.

BACKGROUND/AIMS: Chronic inflammatory status is a possible risk factor for vascular access dysfunction in hemodialysis (HD) patients, but susceptibility differences appear among individuals. Interleukin (IL)-6 is a well-known inflammatory cytokine with various polymorphisms. We examined whether IL-6 polymorphisms are associated with vascular access dysfunction in HD patients. METHODS: A total of 80 HD patients (including 42 diabetic patients) were enrolled. Polymorphisms in the IL-6 gene promoter (-634 C/G and -174 G/C) were studied using restriction length polymorphism polymerase chain reaction analysis. Vascular access patency was compared between the patient groups with respect to IL-6 polymorphisms. An additional 89 healthy individuals were enrolled in the control group. Plasma IL-6 levels were determined by enzyme-linked immunosorbent assay. RESULTS: The GG genotype and G allele at position -634 in the IL-6 promoter were more frequently observed in HD patients than in controls. Furthermore, the distribution of the -634 polymorphism differed according to vascular access patency in non-diabetic HD patients. However, the G allele was not a significant risk factor for early access failure. No significant association appeared between the IL-6 -634 C/G polymorphism and plasma IL-6 levels. The C allele of the IL-6 -174 G/C polymorphism was not detected in our study population. CONCLUSIONS: The IL-6 -634 G allele appears with greater frequently in patients with end-stage renal disease and may be associated with vascular access dysfunction in non-diabetic HD patients.

Early experience of catheter directed thrombolysis for acute limb ischemia of native vessels and bypass graft thrombosis in Thai patients.

OBJECTIVE: We assessed the efficacy and safety of catheter directed thrombolysis in the patients with acute limb ischemia who have been treated with catheter directed thrombolysis. BACKGROUND: From the ACC/AHA 2005 Practice Guidelines for the Management of Patients with Peripheral Arterial Disease, Catheter-based thrombolysis is an effective and beneficial therapy and is indicated for patients with acute limb ischemia (Rutherford categories I and IIa) of less than 14 days'duration. To date, there is no data concerning such treatment in Thai patients. MATERIAL AND METHOD: We retrospectively reviewed data of 66 patients with acute limb ischemia who underwent catheter directed thrombolysis (CDT) at Division of Cardiology, Department of Medicine, Faculty of Medicine Siriraj Hospital between January 2005 and January 2010. RESULTS: Sites of target vessel for CDT were at vascular bypass graft thrombosis (59%) followed by the native vessels artery (41%). Overall technical success rate was 92%. Re-establishment of blood flow was successful from catheter only directed thrombolysis in 41 patients (65%). The other 22 patients needed additional mechanical thrombectomy. Five patients (8%) could not reestablish blood flow after catheter directed thrombolysis with mechanical thrombectomy and underwent bypass surgery. After successful CDT ulcer improvement occurred in 71.42%. ABI improved from 0.45 to 0.93. Major bleeding complications occurred in 4 cases (6%), 1 case due to retroperitoneal bleeding and the other 3 cases due to hemorrhagic stroke (4.5%). The predictor for hemorrhagic stroke was being in the higher age group (72 +/- 1.2 vs. 66.7 +/- 1.8, p = 0.02). CONCLUSION: Catheter directed thrombolysis for treatment of acute limb ischemia in native artery occlusion or bypass graft thrombosis in Thai population has a 92% success rate with an acceptable bleeding complication rate similar to prior published studies. However, the incidence of hemorrhagic stroke is higher in patients older than 70 years.

Factors associated with early failure of infrainguinal lower extremity arterial bypass.

OBJECTIVES: We analyzed the Veterans Affairs (VA) National Surgical Quality Improvement Program (NSQIP), a large clinical database, to investigate which factors, other than technical, were associated with a higher incidence of early graft failure in infrainguinal bypass. METHODS: Data are prospectively collected in NSQIP from 123 participating VA Medical Centers. All patients from 1995 to 2003 in the NSQIP database who underwent infrainguinal arterial bypass were identified by Current Procedural Terminology (CPT) codes (CPT is a registered trademark of the American Medical Association, Chicago, Ill, Copyright 2007). Data for 30-day graft failure were evaluated by univariate analysis, and multivariate logistic regression was used to control for possible confounders. RESULTS: The NSQIP database identified 14,788 patients who underwent infrainguinal lower extremity arterial bypasses during the study period, and 723 acute graft failures (4.9%) occurred. On multivariate analysis, compared with patients aged >70 years, patient ages of <50 and 51 to 60 years were significantly associated with early graft failure (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.6-3.0; P < .001; OR, 1.4; 95% CI, 1.2-1.6, P < .001; respectively); age range of 61 to 70 years was not significantly associated with early graft failure. African American race was also associated with early graft failure, and diabetes mellitus had a negative association with early graft failure (OR, 1.4; 95% CI, 1.3-1.5; P < .001; OR, 0.72; 95% CI, 0.58-0.89; P = .002; respectively). Although smoking was a significant factor for acute graft failure on univariate analysis, it was not significant on multivariate analysis. Multivariate analysis of the type of procedure performed revealed that femoral to popliteal bypass with vein or prosthetic graft was associated with better early graft patency than any of the tibial vessel bypass procedures except for popliteal to tibial bypass with autogenous vein. CONCLUSION: These data suggest that factors other than technique have an effect on the 30-day graft failure rates of infrainguinal bypasses. These results help the vascular surgeon to predict more accurately early bypass failure rates while planning the procedure and counseling patients about its prognosis.

Race independently impacts outcome of infrapopliteal bypass for symptomatic arterial insufficiency.

The impact of racial background on the outcome of lower extremity revascularization is unknown because a majority of studies have a preponderance of white patients. The charts of patients between 1988 and 2004 requiring infrapopliteal lower extremity revascularization were reviewed. Life-table analyses, the Cox proportional hazards model, and log-rank test were used to calculate graft patency and limb salvage. Bypasses were performed on 236 limbs in 225 patients. Mean follow-up was 18 +/- 1.5 months. Twenty-eight (12%) bypasses were performed on whites, 43 (18%) on African Americans, 148 (63%) on Hispanics, and 17 (7.2%) on patients of other races. African American race negatively correlated with primary-assisted patency (hazard ratio 2.9, P = .03), secondary patency (hazard ratio 3.64, P = .02), and limb salvage (hazard ratio 8, P = .006) compared with whites. African American race has a negative impact on the long-term outcome of infrapopliteal revascularization, regardless of disease stage or associated risk factors.

Hemodialysis vascular access: variable thrombus-free survival in three subpopulations of black patients.

Hemodialysis vascular access-related problems account for most hospitalizations in chronic hemodialysis patients. Although some co-morbid risk factors for early fistula failures have been described, a great deal of unknown exists as to why access survival is favorable in some patients. In this longitudinal study, fistulae patency and thrombosis episodes were monitored from placement date in three groups of end-stage renal disease (ESRD) patients who have been on dialysis for > or =90 days. Thirty-six patients (29 male; 80%) with a mean age of 42+/-2 years were monitored. The groups consisted of eight patients with biopsy-confirmed focal segmental glomeruloscierosis (FSGS), 13 with acquired immunodeficiency syndrome-related nephropathy (human immunodeficiency virus [HIV]), and 15 with hypertensive ESRD (hypertensive nephrosclerosis [HTN]) who served as controls. Diabetics and patients aged > or =64 years were excluded. Twenty-five of 36 (69%) fistulae were prosthetic (AVG), while 11 (31%) were native (AVF). The FSGS group was more likely to have an AVG (87.5%), while 54% of the HIV group had an AVG. The thrombosis event rate was significantly greater among the FSGS patients (3/patient-year) than the HIV (0.15/patient-year) and HTN (0.5/patient-year) patients (P < 0.0001 and P < 0.002, respectively). The mean thrombosis-free duration for both AVG and AVF among the HIV and HTN groups were 318.5+/-17 days and 311.7+/-22.5 days, respectively. These were significantly greater than in the FSGS group (26.5+/-7 days; P < 0.0001). The cumulative 1-year patency rate for AVG among the HIV and HTN groups was 85% and 65%, respectively, while that of the FSGS group was 0%. Kaplan-Meier hazard analysis showed that all groups were at risk of access thrombosis as time progressed, but the FSGS group had the highest risk of access thrombosis, which began from the date of placement and increased exponentially with time. The increased thrombosis rate among the patients in the FSGS group correlated with their weight (R = 0.8, P = 0.003) and pre-ESRD 24-hour urinary protein excretion (R = 0.9, P = 0.001). The HIV status appeared to confer enhanced hemodialysis access survival. This may be related to the high rate of native fistulae placement and favorable vascular reactivity to shear stress. Accelerated atherosclerosis and small caliber vessels may be responsible for the poor fistulae outcome among the FSGS group. More studies will be necessary to further explore these findings.