Theodore H. Yuo

Treatment strategies of arterial steal after arteriovenous access

INTRODUCTION Ischemic steal syndrome (ISS) associated with arteriovenous (AV) access is rare but can result in severe complications. Multiple techniques have been described to treat ISS with varying degrees of success. This study compares the management and success associated with these techniques. METHODS Patients with ISS between June 2003 and June of 2008 at the University of Pittsburgh Medical Center were retrospectively reviewed. Demographics, type of AV access, management technique, and success of intervention were recorded. Success was defined as resolution of ISS symptoms while preserving access function. One hundred consecutive AV access procedures were reviewed for comparison. Data were analyzed using χ(2) test, Fishers exact test, and Students t test. The study was approved by our institutional review board. RESULTS A total of 114 patients with ISS had a mean age of 65 years (range, 20-90 years), were predominantly female (66%), diabetic (61%), and with a brachial origin fistula (69%). Risk factors for ISS included coronary artery disease (CAD; P < .001), hypertension (P < .001), and tobacco use (P = .048). Women were noted to have a brachial origin access more frequently than men (odds ratio [OR], 3.1; P = .009). Forty-four patients with mild steal were observed. Seventy patients underwent 87 procedures. Procedures performed included ligation (n = 27), banding (n = 22), distal revascularization and interval ligation (DRIL; n = 21), improvement of proximal inflow (n = 9), revision using distal inflow (RUDI; n = 4), and proximalization of arterial inflow (PAI; n = 3). Early procedures (<30 days from the index fistula) were mostly ligation (50%) or banding (38%), while DRIL was the most frequent choice for late interventions (41%). Banding had a high failure rate (62%) and was the most common reason for reintervention (8 of 11, 73%) and DRIL had a better success rate than banding (P ≤ .05). In our current practice, 18% of patients had an AV fistula with the proximal radial artery (PRA) as the inflow source, while this type of fistula accounted for only 2% of all ISS patients. Ligation resolved symptoms in all patients, but the AV access was lost. CONCLUSIONS Risk factors for development of ISS include CAD, diabetes, female gender, hypertension, and tobacco use. Among various options to treat ISS, banding has a low success rate and high likelihood for reintervention, while DRIL is particularly effective although not uniformly. Less invasive treatment options such as RUDI and PAI may be quite effective in treating ISS. Use of the PRA as the inflow source may decrease the incidence of ISS.

Arteriovenous grafts are associated with earlier catheter removal and fewer catheter days in the United States Renal Data System population

OBJECTIVE Arteriovenous fistulas (AVFs) are associated with improved long-term outcomes but longer maturation times and higher primary failure rates compared with arteriovenous grafts (AVGs). The Fistula First Breakthrough Initiative has recently emphasized tunneled dialysis catheter (TDC) avoidance. We sought to characterize the relationship of AVFs and AVGs to the use of TDCs as well as secondary procedures. METHODS Using the United States Renal Data System (USRDS) database, we identified incident hemodialysis (HD) patients in 2005 that started HD with a TDC and survived at least 1 year. We then monitored them through 2008. Access creation, TDC removal, TDC placement, and secondary procedures were identified by Current Procedural Terminology codes (American Medical Association, Chicago, Ill). Multivariate logistic regression was used to identify risk factors for the primary end points. RESULTS In 2005, HD was initiated in 56,495 patients, 74% with a TDC. Of these, 6286 had an access procedure ≤3 months and 1 year of follow-up (AVF, 4634; AVG, 1652). Mean age was 67.7 years (AVF, 67.3; AVG, 68.7 years; P < .001), 53.3% were men (AVF, 58.1%; AVG, 40.5%; P < .001), and 33.8% were obese (AVF, 33.6%; AVG, 34.4%; P = not significant). AVG placement was associated with a higher TDC removal at 1 (7.9% vs 3.1%; P < .001), 3 (47.8% vs 17.8%; P < .001), and 6 (60.6% vs 47.2%; P < .001) months. There was no difference at 9 months (AVG, 64.9% vs AVF, 62.3%; P = .06). The median time to TDC removal was lower in the AVG group (70 days vs 155 days; P < .001). Multivariable model found AVFs were associated with decreased odds of TDC removal at 3 (odds ratio, 0.22; P < .001) and 6 months (odds ratio, 0.54; P < .001). AVGs required more secondary procedures than AVFs at all time points up to 1 year and specifically had increased thrombectomy procedures (39.8% vs 11.5%; P < .001). CONCLUSIONS In patients starting dialysis with a TDC, AVGs are associated with increased TDC removal and fewer catheter days compared with AVFs at up to 6 months. However, AVGs require more secondary procedures at all time points up to 1 year.

Patients started on hemodialysis with tunneled dialysis catheter have similar survival after arteriovenous fistula and arteriovenous graft creation

OBJECTIVE Current guidelines suggest that arteriovenous fistula (AVF) is associated with survival advantage over arteriovenous graft (AVG). However, AVFs often require months to become functional, increasing tunneled dialysis catheter (TDC) use, which can erode the benefit of an AVF. We sought to compare survival in patients with end-stage renal disease after creation of an AVF or AVG in patients starting hemodialysis (HD) with a TDC and to identify patient populations that may benefit from preferential use of AVG over AVF. METHODS Using U.S. Renal Data System databases, we identified incident HD patients in 2005 through 2008 and observed them through 2008. Initial access type and clinical variables including albumin levels were assessed using U.S. Renal Data System data collection forms. Attempts at AVF and AVG creation in patients who started HD through a TDC were identified by Current Procedural Terminology codes. We accounted for the effect of changes in access type by truncating follow-up when an additional AVF or AVG was performed. Survival curves were then constructed, and log-rank tests were used for pairwise survival comparisons, stratified by age. Multivariate analysis was performed with Cox proportional hazards regressions; variables were chosen using stepwise elimination. An interaction of access type and albumin level was detected, and Cox models using differing thresholds for albumin level were constructed. The primary outcome was survival. RESULTS Among the 138,245 patients who started with a TDC and had complete records amenable for analysis, 22.8% underwent AVF creation (mean age ± standard deviation, 68.9 ± 12.5 years; 27.8% mortality at 1 year) and 7.6% underwent AVG placement (70.2 ± 12.0 years; 28.2% mortality) within 3 months of HD initiation; 69.6% remained with a TDC (63.2 ± 15.4 years; 33.8% mortality). In adjusted Cox proportional hazards regression, AVF creation is equivalent to AVG placement in terms of survival (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.93-1.02; P = .349). AVG placement is superior to continued TDC use (HR, 1.54; 95% CI, 1.48-1.61; P < .001). In patients older than 80 years with albumin levels >4.0 g/dL, AVF creation is associated with higher mortality hazard compared with AVG creation (HR, 1.22; 95% CI, 1.04-1.43; P = .013). CONCLUSIONS For patients who start HD through a TDC, placement of an AVF and AVG is associated with similar mortality hazard. Further study is necessary to determine the ideal access for patients in whom the survival advantage of an AVF over an AVG is uncertain.

Revascularization of asymptomatic carotid stenosis is not appropriate in patients on dialysis

OBJECTIVE Outcomes of carotid endarterectomy (CEA) or carotid angioplasty and stenting (CAS) for asymptomatic disease in patients on dialysis are not well characterized, with questionable stroke prevention and survival. This study reports outcomes of carotid revascularization in asymptomatic dialysis patients in the United States. METHODS Using United States Renal Data System (USRDS) databases, we identified all dialysis patients who underwent CEA or CAS for asymptomatic disease from 2005 to 2008. CEA and CAS were identified by Current Procedural Terminology (American Medical Association, Chicago, Ill) codes, and symptom status and comorbidities by International Classification of Diseases-9th Revision, Clinical Modification codes. Primary outcomes were stroke, cardiac complications, and death at 30 days and at 1 and 3 years. Predictors of death were identified using multivariate regression models. RESULTS Of 738,561 dialysis patients, 2131 asymptomatic patients underwent carotid revascularization (1805 CEA, 326 CAS). The mortality rate was 4.7% at 30 days (4.6% CEA, 4.9% CAS; P = .807). Kaplan-Meier estimates of survival were 75.1% at 1 year (75.9% CEA, 70.7% CAS) and 43.4% at 3 years (43.7% CEA, 41.6% CAS). The stroke rate was 6.5% at 30 days (6.4% CEA, 6.9% CAS; P = .774) and 13.6% at 1 year (13.3% CEA, 15.0% CAS; P = .490). Cardiac complications occurred in 22.0% of patients (3.3% myocardial infarction) at 30 days (22.2% CEA, 20.6% CAS; P = .525). The combined stroke or death rate was 10.2% at 30 days (10.1% CEA, 10.9% CAS; P = .490) and 33.5% at 1 year (32.2% CEA, 39.6% CAS; P = .025). Age >70 years at the time of surgery and increased time on dialysis were predictive of death, whereas a history of renal transplant was a protective factor. CONCLUSIONS Patients on dialysis have high perioperative and long-term stroke or death rates after CEA or CAS for asymptomatic stenosis, with a median survival that is less than recommended by current guidelines. As a result, carotid intervention in these patients appears to be inappropriate.

Outcomes of endovascular lower extremity interventions depend more on indication than physician specialty

OBJECTIVE Outcomes of endovascular lower extremity interventions (eLEIs) have been recently linked to provider specialty; however, the indication for intervention was not examined. We sought to compare outcomes between specialties performing eLEI for different indications, in a recent statewide inpatient discharge dataset. METHODS The Florida hospital discharge data from 2005 to 2009 were reviewed for patients with LEI during hospitalization. We assigned provider specialty as interventional radiology (IR), interventional cardiology (IC), or vascular surgery (VS) based on provider-associated procedures. Clinical indication was claudication or critical limb ischemia (CLI). We limited our analysis to patients without concomitant open surgery during hospitalization. We compared mortality, length of stay (LOS), major use of intensive care unit (ICU), discharge disposition, and total charges between specialties with regression models, both unadjusted and adjusted for demographic and clinical characteristics. RESULTS A total of 15,398 patients (47% with CLI) had an eLEI. Clinical indication was significantly associated with provider type (P < .001) and outcomes. VS and IR were more likely than IC to treat CLI patients (VS 59%, IR 65%, IC 26%; P < .001). IC performed the majority of procedures on claudicants (VS 30%, IC 57%, IR 13%; P < .001), while VS performed the majority of procedures on CLI patients (VS 50%, IC 23%, IR 27%; P < .001). Adjusted analyses demonstrated no difference in mortality rates between the three specialties (odds ratio [OR] VS: reference, IR: 1.24, IC: 0.79; P = NS for both). However, compared with VS, IR-treated patients were less likely to be discharged home (OR, 0.74; P < .001), LOS was longer (β, 1.16 days; P < .001), major ICU use was more common (OR, 1.49; P < .001), and total charges were higher (β,

Applying the payoff time framework to carotid artery disease management.

341; P = .001). CLI predicted poorer results for all outcomes: death (OR, 4.19; P < .001), discharge home (OR, 0.50; P < .001), increased LOS (β, 3.26 days; P < .001), major ICU use (OR, 1.95; P < .001), and total charges (β,

Effect of hospital-level variation in the use of carotid artery stenting versus carotid endarterectomy on perioperative stroke and death in asymptomatic patients

18,730; P < .001). CONCLUSIONS The majority of eLEI done by VS are for CLI, whereas the majority of patients treated by IC are claudicants. Although provider specialty does correlate with several clinical results, the clinical indication for eLEI is a stronger predictor of adverse outcomes. Future analyses of eLEI should adjust for clinical indication.

The associations of hemodialysis access type and access satisfaction with health-related quality of life

Background and Objective: Asymptomatic stenosis of the carotid arteries is associated with stroke. Carotid revascularization can reduce the future risk of stroke but can also trigger an immediate stroke. The objective was to model the generic relationship between immediate risk, long-term benefit, and life expectancy for any one-time prophylactic treatment and then apply the model to the use of revascularization in the management of asymptomatic carotid disease. Methods: In the “payoff time” framework, the possibility of losing quality-adjusted life-years (QALYs) because of revascularization failure is conceptualized as an “investment” that is eventually recouped over time, on average. Using this framework, we developed simple mathematical forms that define relationships between the following: perioperative probability of stroke (P); annual stroke rate without revascularization (r0); annual stroke rate after revascularization, conditional on not having suffered perioperative stroke (r1); utility levels assigned to the asymptomatic state (ua) and stroke state (us); and mortality rates (λ). Results: In patients whose life expectancy is below a critical life expectancy ( CLE = P ( 1 − P ) r 0 − r 1 ) , the “investment” will never pay off, and revascularization will lead to loss of QALYs, on average. CLE is independent of utilities assigned to the health states if a rank ordering exists in which ua > us. For clinically relevant values (P = 3%, r0 = 1%, r1 = 0.5%), the CLE is approximately 6.4 years, which is longer than published guidelines regarding patient selection for revascularization. Conclusions: In managing asymptomatic carotid disease, the payoff time framework specifies a CLE beneath which patients, on average, will not benefit from revascularization. This formula is suitable for clinical use at the patient’s bedside and can account for patient variability, the ability of clinicians who perform revascularization, and the particular revascularization technology that is chosen.

Cephalic vein transposition is a durable approach to managing cephalic arch stenosis

OBJECTIVE Perioperative stroke and death (PSD) are more common after carotid artery stenting (CAS) than after carotid endarterectomy (CEA) in symptomatic patients, but whether this is also true in asymptomatic patients is unclear. Furthermore, use of both CEA and CAS varies geographically, suggesting possible variation in outcomes. We compared odds of PSD after CAS and CEA in asymptomatic patients to determine the impact of this variation. METHODS We identified CAS and CEA procedures and hospitals where they were performed from 2005 to 2009 California hospital discharge data. Preoperative symptom status and medical comorbidities were determined using administrative codes. We compared PSD rates after CAS and CEA using logistic regression and propensity score matching. We quantified hospital-level variation in the relative utilization of CAS by calculating hospital-specific probabilities of CAS use among propensity score-matched patients. We then calculated a weighted average for each hospital and used this as a predictor of PSD. RESULTS We identified 6053 CAS and 36,524 CEA procedures that were used to treat asymptomatic patients in 278 hospitals. Perioperative stroke and death occurred in 250 CAS and 660 CEA patients, yielding unadjusted PSD rates of 4.1% and 1.8%, respectively (P < .001). Compared with CAS patients, CEA patients were more likely to be older than 70 years (66% vs 62%; P < .001) but less likely to have three or more Elixhauser comorbidities (37% vs 39%; P < .001). Multivariate models demonstrated that CAS was associated with increased odds of PSD (odds ratio [OR], 1.865; 95% confidence interval [CI], 1.373-2.534; P < .001). Estimation of average treatment effects based on propensity scores also demonstrated 1.9% increased probability of PSD with CAS (P < .001). The average probability of receiving CAS across all hospitals and strata was 13.8%, but the interquartile range was 0.9% to 21.5%, suggesting significant hospital-level variation. In univariate analysis, patients treated at hospitals with higher CAS utilization had higher odds of PSD compared with patients in hospitals that performed CAS less (OR, 2.141; 95% CI, 1.328-3.454; P = .002). Multivariate analysis did not demonstrate this effect but again demonstrated higher odds of PSD after CAS (OR, 1.963; 95% CI, 1.393-2.765; P < .001). CONCLUSIONS Carotid endarterectomy has lower odds of PSD compared with CAS in asymptomatic patients. Increased utilization of CAS at the hospital level is associated with increased odds of PSD among asymptomatic patients, but this effect appears to be related to generally worse outcomes after CAS compared with CEA.

Immediate-access grafts provide comparable patency to standard grafts, with fewer reinterventions and catheter-related complications

Objective In addition to age and comorbidities, health‐related quality of life (HRQOL) is known to predict mortality in hemodialysis (HD) patients. Understanding the association of vascular access type with HRQOL can help surgeons to provide patient‐centered dialysis access recommendations. We sought to understand the impact of HD access type on HRQOL. Methods We conducted a cross‐sectional prospective study of community‐dwelling prevalent HD patients in Pittsburgh, Pennsylvania. We assessed patient satisfaction with their access using the Vascular Access Questionnaire (VAQ) and HRQOL with the Short Form Health Survey. We compared access satisfaction and HRQOL across access types. We used logistic regression modeling to evaluate the association of access type with satisfaction and multivariate analysis of variance to evaluate the association of both of these variables on HRQOL. Results We surveyed 77 patients. The mean age was 61.8 ± 15.9 years. Arteriovenous fistula (AVF) was used by 62.3%, tunneled dialysis catheter (TDC) by 23.4%, and arteriovenous graft (AVG) by 14.3%. There was a significant difference in satisfaction by access type with lowest median VAQ score (indicating highest satisfaction) in patients with AVF followed by TDC and AVG (4.5 vs 6.5 vs 7.0; P = .013). Defining a VAQ score of <7 to denote satisfaction, AVF patients were more likely to be satisfied with their access, compared with TDC or AVG (77% vs 56% vs 55%; P = NS). Multivariate regression analysis yielded a model that predicted 46% of the variance of VAQ score; important predictors of dissatisfaction included <1 year on dialysis (&bgr; = 3.36; P < .001), increasing number of access‐related hospital admissions in the last year (&bgr; = 1.69; P < .001), and AVG (&bgr; = 1.72; P = .04) or TDC (&bgr; = 1.67; P = .02) access. Mean physical and mental QOL scores (the composite scores of Short Form Health Survey) were not different by access type (P = .49; P = .41). In an additive multivariate analysis of variance with the two composite QOL scores as dependent variables, 25.8% of the generalized variance in HRQOL (effect size) was accounted for by access satisfaction with only an additional 3% accounted for by access type. Conclusions HD patients experience greatest satisfaction with fistula, and access satisfaction is significantly associated with better HRQOL. Controlling for access satisfaction, there is no significant independent association of access type on HRQOL. Future research should investigate the relationship between access satisfaction, adherence to dialysis regimens, mortality, and the consequent implications for patient‐centered care.