Isibor Arhuidese

Trends in Incident Hemodialysis Access and Mortality

IMPORTANCE Based on evidence of survival benefit when initiating hemodialysis (HD) via arteriovenous fistula (AVF) or arteriovenous graft (AVG) vs hemodialysis catheter (HC), the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative published practice guidelines in 1997 recommending 50% or greater AVF rates in incident HD patients. A decade after, lapses exist and the impact on HD outcomes is uncertain. OBJECTIVE To assess the achievement of the practice goals for incident vascular access and the effects on HD outcomes. DESIGN, SETTING, AND PARTICIPANTS This retrospective cohort study was conducted using the US Renal Data System. All patients with end-stage renal disease in the United States without prior renal replacement therapy who had incident vascular access for HD created between January 1, 2006, and December 31, 2010 (N = 510 000) were included. MAIN OUTCOMES AND MEASURES Incident vascular access use rates and mortality. Relative mortality was quantified using multivariable Cox proportional hazard models. Coarsened exact matching and propensity score-matching techniques were used to better account for confounding by indication. RESULTS Of 510 000 patients included in this study, 82.6% initiated HD via HC, 14.0% via AVF, and 3.4% via AVG. Arteriovenous fistula use increased only minimally, from 12.2% in 2006 to 15.0% in 2010. Patients initiating HD with AVF had 35% lower mortality than those with HC (adjusted hazard ratio, 0.65; 95% CI, 0.64-0.66; P < .001). Those initiating HD with AVF had 23% lower mortality than those initiating with an HC while awaiting maturation of an AVF (adjusted hazard ratio, 0.77; 95% CI, 0.76-0.79; P < .001). CONCLUSIONS AND RELEVANCE Current incident AVF practice falls exceedingly short years after recommendations were made in 1997. The impact of this shortcoming on mortality for patients with end-stage renal disease is enormous. Functioning permanent access at initiation of HD confers lower mortality even compared with patients temporized with an HC while awaiting maturation of permanent access. A change of current policies and structured multidisciplinary efforts are required to establish matured fistulae prior to HD to ameliorate this deficit in delivering care.

Perioperative mortality following repair of abdominal aortic aneurysms: Application of a randomized clinical trial to real-world practice using a validated nationwide data set

IMPORTANCE Because of the restrictions applied to the conduct of randomized clinical trials, the risks reported in their comparison of open and endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAA) may not be applicable to real-world vascular surgical practice. The magnitude of this deviation is indeterminate. OBJECTIVES To compare 30-day mortality from the recent Open Vs Endovascular Repair (OVER) Veterans Affairs Cooperative trial with results obtained from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) and to assess temporal trends in perioperative mortality. DESIGN, SETTING, AND PARTICIPANTS We analyzed data from 21,115 patients who received elective EVAR or open repair for asymptomatic infrarenal AAA between January 1, 2005, and December 31, 2011, in the NSQIP database. We used χ2 and t tests to compare perioperative mortality between groups. Logistic regression was used to analyze perioperative mortality, adjusting for age, sex, race, and comorbidities. The outcomes of the OVER trial were then compared with the national estimates obtained from the NSQIP. MAIN OUTCOMES AND MEASURES Death within 30 days of surgery. RESULTS Perioperative mortality was 3.7% (95% CI, 3.2%-4.3%) after open repair and 1.3% (95% CI, 1.2%-1.5%) after EVAR. There was a 70% reduction in operative mortality after EVAR compared with open repair (adjusted odds ratio [aOR], 0.30; 95% CI, 0.25-0.38; P < .001). Mortality was significantly lower in men compared with women (aOR, 0.73; 95% CI, 0.57-0.92; P = .009). Thirty-day mortality in the NSQIP cohort was higher than that reported in the OVER trial for both EVAR and open repair (EVAR, 1.3% vs 0.2%; open, 3.7% vs 2.3%). There was an increase in the proportion of patients who received EVAR during the 7 years studied (65% in 2005 and 80% in 2011). There has been no significant decrease in perioperative mortality during these years (P > .05). CONCLUSIONS AND RELEVANCE Perioperative mortality reported by the OVER trial is significantly lower than outcomes from practices outside the restriction of randomized clinical trials. We attribute this difference to the fact that the OVER trial excluded high-risk patients deemed unfit for open repair. This finding supports the need for individualized assessment of risk and treatment selection for patients with infrarenal AAA. There has been no change in perioperative mortality after EVAR in recent years despite improvements in techniques, devices, and proficiency.

Racial/Ethnic Disparities Associated With Initial Hemodialysis Access

IMPORTANCE Superior outcomes have been established with the use of an arteriovenous fistula (AVF) at first hemodialysis. However, considering the influence of comorbidities, medical insurance, and specialist care, racial/ethnic differences in the patterns of utilization of AVFs are unknown and deserve evaluation. OBJECTIVE To assess national trends in initial hemodialysis access with respect to race/ethnicity stratified by comorbid disease, nephrology care, and medical insurance status within the US Renal Data System. DESIGN, SETTING, AND PARTICIPANTS A retrospective analysis of all patients with end-stage renal disease in the US Renal Data System who initiated hemodialysis between January 1, 2006, and December 31, 2010. Univariable statistics (χ² test and analysis of variance) and logistic regression were used to compare racial/ethnic groups (white vs black vs Hispanic). Multivariable logistic regression and propensity score-matching techniques were used to evaluate hemodialysis access rates between patients of different races/ethnicities with comparable characteristics. MAIN OUTCOMES AND MEASURES Utilization rates of AVF, arteriovenous graft, and intravascular hemodialysis catheter. RESULTS In this cohort of 396,075 patients, more white patients initiated hemodialysis with an AVF than black patients or Hispanic patients (18.3% vs 15.5% and 14.6%, respectively; P < .001). Black patients and Hispanic patients initiated hemodialysis with an AVF less frequently despite being younger and having less coronary artery disease, chronic obstructive pulmonary disease, and cancer than white patients with an AVF. When stratified by medical insurance status, black patients (odds ratios, 0.90 [95% CI, 0.82-0.98] for uninsured and 0.85 [95% CI, 0.84-0.87] for insured) and Hispanic patients (odds ratios, 0.72 [95% CI, 0.65-0.81] for uninsured and 0.81 [95% CI, 0.79-0.84] for insured) persistently initiated hemodialysis with an AVF less frequently than white patients (P < .05 for all). Arteriovenous fistula utilization at initial hemodialysis was lower among black patients (odds ratio, 0.81 [95% CI, 0.78-0.84]) and Hispanic patients (odds ratio, 0.86 [95% CI, 0.82-0.90]) compared with white patients within the category of patients who had nephrology care for longer than 1 year (P < .001 for all). CONCLUSIONS AND RELEVANCE Black patients and Hispanic patients tend to initiate hemodialysis with an AVF less frequently than white patients despite being younger and having fewer comorbidities. These disparities persisted independent of factors that drive health access for fistula placement, such as medical insurance status and nephrology care. The sociocultural underpinnings of these disparities deserve investigation and redress to maximize the benefits of initiating hemodialysis via fistula in patients with end-stage renal disease irrespective of race/ethnicity.

Mortality benefits of different hemodialysis access types are age dependent.

OBJECTIVE Risk of death in dialysis patients is lowest with arteriovenous fistulas (AVFs), followed by arteriovenous grafts (AVGs) and then intravenous hemodialysis catheters (HCs). Our aim was to analyze the effects of age at hemodialysis initiation on mortality across different access types. METHODS All patients ≥18 years in the United States Renal Data System between the years 2006 and 2010 were analyzed. Spline modeling and risk-adjusted Cox proportional hazard models were used to analyze the effect of age on mortality for first dialysis access with AVF vs AVG vs HC. RESULTS The study analyzed 507,791 patients (63.4 ± 0.02 years; 56.5% male; 40.9% mortality; follow-up, 1.57 ± 1.36 years). Increasing age was a significant predictor of overall mortality (adjusted hazard ratio [aHR], 1.03; P < .001). Compared with patients with HCs (n = 418,932), overall risk-adjusted mortality was lowest in patients with AVFs (n = 71,316; aHR, 0.63; P < .001) followed by AVGs (n = 17,543; aHR, 0.83; P < .001). AVF was superior to both HC and AVG for all age groups (P < .001). However, there was a significant change in the relative efficacy of AVG at ages 48 years and 89 years based on spline modeling; there were no significant differences comparing adjusted mortality with AVG vs HC for patients aged 18 to 48 years or for patients >89 years, but AVG was superior to HC for patients 49 to 89 years of age (aHR, 0.811; P < .001). The mortality benefit of AVF was consistently superior to that of AVG and HC for patients of all ages (all, P < .001). CONCLUSIONS AVF is superior to AVG and HC regardless of the patients age, including in octogenarians. In contrast, the mortality benefit of AVG over HC may not apply to younger (18-48 years) or older (>89 years) age groups. All patients 18 to 48 years should receive AVF for dialysis access whenever possible.

Hospital-Level Factors Associated With Mortality After Endovascular and Open Abdominal Aortic Aneurysm Repair

IMPORTANCE Endovascular technology has become ubiquitous in the modern care of abdominal aortic aneurysm (AAA), yet broad estimates of its efficacy among variable hospital and regional settings is not known. OBJECTIVE To perform a preliminary analysis of hospital effects on mortality following open AAA repair (OAR) and endovascular AAA repair (EVAR). DESIGN, SETTING, AND PARTICIPANTS A retrospective analysis of the American College of Surgeons National Surgical Quality Improvement Program database was conducted on all patients undergoing OAR or EVAR from July 1, 2010, to November 30, 2012, using Current Procedural Terminology codes. MAIN OUTCOMES AND MEASURES Weight-adjusted 30-day observed to expected mortality ratios were compared based on hospital type (academic vs community) and size (100-299 beds vs 300-500 beds vs >500 beds). RESULTS Data on 11,250 patients (2466 underwent OAR and 8784 underwent EVAR) were analyzed. Endovascular AAA repair was performed more frequently than OAR at both academic (78.8%) and community (68.2%) hospitals. Overall 30-day mortality was 14.0% for OAR and 4.3% for EVAR (P < .001). Hospital size was significantly associated with mortality for OAR (observed to expected mortality ratio: >500 beds, 0.88 vs 300-500 beds, 1.11 vs 100-299 beds, 1.59; P = .01) but not for EVAR (P = .27). In contrast, hospital type was significantly associated with mortality for EVAR (observed to expected mortality ratio: academic, 0.60 vs community, 2.60; P < .001) but not OAR (P = .46). Multivariable analysis of hospital-level factors suggested that, for all outcomes, academic hospital type was the single most significant predictor of reduced mortality following AAA repair (observed to expected mortality ratio: academic, 0.91 vs community, 2.00; P = .05). CONCLUSIONS AND RELEVANCE Based on this preliminary report, outcomes for both OAR and EVAR appear to depend greatly on hospital-level effects. The relative safety of EVAR vs OAR may depend on appropriate patient selection and adequate access to multidisciplinary care in order to minimize failure to rescue rates and improve survival.

Surgeon’s 30-Day Outcomes Supporting the Carotid Revascularization Endarterectomy versus Stenting Trial

IMPORTANCE While the Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST) has been widely accepted as a landmark trial establishing an equivalent risk of major adverse events following carotid endarterectomy (CEA) or carotid artery stenting (CAS), the applicability of these findings to single centers has been questioned owing to the rigid selection criteria for investigators in the study. Although refuted by the findings of a subsequent study, a substudy of CREST established a higher periprocedural stroke rate for CAS when the surgeon was a vascular surgeon. OBJECTIVE To present our 30-day results of stroke, death, myocardial infarction, and composite major adverse events to determine if a single vascular surgeons outcomes at our hospital are consistent with the results of CREST. DESIGN, SETTING, AND PARTICIPANTS A retrospective analysis of patients with high-grade carotid artery stenosis treated with CEA or CAS by a vascular surgeon at our institution from September 9, 2005, through December 17, 2012, was performed. A χ2 analysis was used to compare the incidence of specific high-risk patient characteristics in each group. The Fisher exact test was used to compare the risks of stroke, death, myocardial infarction, and composite major adverse events between CEA and CAS. These results were then compared with those reported in CREST. RESULTS A total of 182 cases (94 CAS and 88 CEA) performed by a single vascular surgeon were included for analysis. While in CREST the periprocedural risk of stroke was higher following CAS (4.1% vs 2.3%, P = .01) and the risk of myocardial infarction was higher following CEA (2.3% vs 1.1%, P = .03), there was no significant difference in the incidence of these outcomes between the 2 treatment modalities in our study. When compared with CREST, our rates of myocardial infarction, stroke, death, and composite adverse events (CEA, 4.5% vs 3.4%; P = .79; CAS, 5.2% vs 4.3%; P >.99) were no different. CONCLUSIONS AND RELEVANCE Similar to CREST, the 30-day risk of composite major adverse events was equivalent for the 2 treatment modalities. We attribute our comparable incidence of perioperative stroke with CAS and CEA to improved patient selection. We excluded most patients older than 80 years and those with complex anatomy from consideration for CAS. Our results confirm those of CREST and demonstrate that both CEA and CAS can be performed safely by a vascular surgeon in properly selected patients.

The Age Effect in Increasing Operative Mortality following Delay in Elective Abdominal Aortic Aneurysm Repair

BACKGROUND Elective repair of large abdominal aortic aneurysms (AAAs) is associated with the risk of significant perioperative mortality. When abdominal aneurysm repair is delayed, patients with asymptomatic large AAAs face the risk of death from rupture. In addition to the risk of rupture, the advancing age of the patients adds a future operative risk. This risk has been historically documented in age groups. However, a more accurate representation of the increasing operative risk with age is needed. METHODS We analyzed all patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent endovascular or open repair for asymptomatic infrarenal AAA between 2005 and 2012. Multivariable logistic regression was used to evaluate the effect of increasing age and operative delay on 30-day postoperative mortality. RESULTS There were 27,576 patients who underwent AAA repair during the study period (mean age 73.5 years, standard deviation 8.6, 80% male, 24% open repair). There was a linear relative increase of 5% (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.04-1.06, P < 0.001) in the odds of operative death after AAA repair with each year of operative delay irrespective of treatment approach. There was a linear relative increase of 4% for endovascular aneurysm repair (OR 1.04, 95% CI 1.02-1.05, P < 0.001) and 6% for open repair (OR 1.06, 95% CI 1.04-1.08, P < 0.001) with each year of delay in repair. CONCLUSIONS Because of increasing age, delay in surgery is associated with uniform increase in the risk of perioperative mortality in asymptomatic patients who meet criteria for AAA repair. It is important for surgeons to incorporate this more accurate estimation of operative risk into discussions with patients who qualify for treatment yet decide to forgo surgery for the repair of their AAA.

Perioperative and Long-term Outcomes After Carotid Endarterectomy in Hemodialysis Patients

Importance Early landmark trials excluding dialysis patients showed carotid endarterectomy (CEA) decreased stroke risk compared with medical management. Dialysis dependence has been associated with poor outcomes after CEA in small studies, but, to our knowledge, there are no large studies evaluating outcomes of CEA in this patient group. Objective To delineate perioperative and long-term outcomes after CEA in dialysis-dependent patients in a large national database. Design, Setting, and Participants A retrospective review of all patients who underwent CEA in the US Renal Disease System-Medicare-matched database between January 1, 2006, and December 31, 2011, was performed in June 2015. The median follow-up time was 2.5 years. Logistic and Cox regression analyses were used to evaluate perioperative and long-term outcomes. Main Outcomes and Measures The primary outcomes of interest were perioperative stroke, myocardial infarction and mortality, and long-term stroke and mortality. Results A total of 5142 patients were studied; 83% of whom were asymptomatic. The mean (SD) age was 68.9 (9.6) years for asymptomatic patients and 70.0 (9.1) years for symptomatic patients. The 30-day stroke rate, myocardial infarction, and mortality for the asymptomatic and symptomatic groups were 2.7% vs 5.2% (P = .001), 4.6% vs 5.0% (P = .69), and 2.6% vs 2.9% (P = .61), respectively. Predictors of perioperative stroke were symptomatic status (odds ratio [OR], 2.01; 95% CI, 1.18-3.42; P = .01), black race (OR, 2.30; 95% CI, 1.24-4.25; P = .008), and Hispanic ethnicity (OR, 2.28; 95% CI, 1.17-4.42; P = .02). Freedom from stroke and overall survival were lower in symptomatic compared with asymptomatic patients at 1, 2, 3, 4, and 5 years (in asymptomatic vs symptomatic patients, freedom from stroke rates were 92% vs 87% at 1 year, 88% vs 83% at 2 years, 84% vs 78% at 3 years, 80% vs 73% at 4 years, and 79% vs 69% at 5 years, respectively, and overall survival rates were 78% vs 73% at 1 year, 60% vs 57% at 2 years, 46% vs 42% at 3 years, 37% vs 32% at 4 years, and 33% vs 29% at 5 years; P < .05). Predictors of long-term stroke were preoperative symptoms (hazard ratio, 1.67; 95% CI, 1.24-2.24; P < .001), female sex (hazard ratio, 1.34; 95% CI, 1.03-1.73; P = .04), and inability to ambulate (hazard ratio, 1.81; 95% CI, 1.25-2.62; P = .002). Predictors of long-term mortality were increasing age (OR, 1.02; 95% CI, 1.01-1.03; P < .01), active smoking (OR, 1.22; 95% CI, 1.00-1.48; P = .045), history of congestive heart failure (OR, 1.25; 95% CI, 1.12-1.39; P < .001), and chronic obstructive pulmonary disease (OR, 1.26; 95% CI, 1.09-1.45; P = .002). Conclusions and Relevance To our knowledge, this is the largest study to date of dialysis patients who have undergone CEA. We have shown that the risks of CEA in asymptomatic patients is high and may outweigh the benefits. The risk of CEA in symptomatic patients is also high, and it should only be offered to a small carefully selected cohort of symptomatic patients.

Comprehensive Assessment of Factors Associated With In-Hospital Mortality After Elective Abdominal Aortic Aneurysm Repair.

IMPORTANCE Patient- and hospital-level factors affecting outcomes after open and endovascular abdominal aortic aneurysm (AAA) repair are each well described separately, but not together. OBJECTIVE To describe the association of patient- and hospital-level factors with in-hospital mortality after elective AAA repair. DESIGN, SETTING, AND PARTICIPANTS Retrospective review of the Nationwide Inpatient Sample database (January 2007-December 2011). The review included all patients undergoing elective open AAA repair (OAR) or endovascular AAA repair (EVAR) and was conducted between December 2014 and January 2015. MAIN OUTCOMES AND MEASURES Factors associated with in-hospital mortality were analyzed for OAR and EVAR using multivariable analyses, adjusting for previously defined patient- and hospital-level risk factors. RESULTS Of the 166 443 surgeries (131 908 EVARs and 34 535 OARs) that were performed at 1207 hospitals, 133 407 patients (80.2%) were men, 123 522 patients (89.6%) were white, and the mean (SD) age was 73 (0.04) years. Overall in-hospital mortality was 0.7% for EVAR and 3.8% for OAR. Mortality after EVAR was significantly higher among hospitals with high general surgery mortality (mortality quartile ≥ 50%; odds ratio [OR], 1.37; 95% CI, 1.01-1.86; P = .04) and there was no difference in mortality among hospitals meeting the Leapfrog criteria for AAA repair (OR, 0.64; 95% CI, 0.38-1.09; P = .09). Mortality after OAR was significantly lower among hospitals performing at least 25% of AAA repairs using open techniques (OR, 0.68; 95% CI, 0.52-0.88; P = .004). Neither hospital bed size nor teaching status was significantly associated with mortality after either EVAR or OAR. Overall, OAR (OR, 6.07; 95% CI, 4.92-7.49) and intrinsic patient risk (Medicare score; OR, 4.81; 95% CI, 3.45-6.72) were most likely associated with in-hospital mortality after AAA repair, although hospitals with poor general surgery performance (OR, 1.31; 95% CI, 1.06-1.63) and those with at least a 25% proportion of open cases (OR, 1.39; 95% CI, 1.10-1.75) were also significantly associated with mortality (all P < .002). Notably, the proportion of institutions performing at least 25% open cases fell from 41% in 2007 to 18% in 2011 (P < .001). CONCLUSIONS AND RELEVANCE Patient-level factors were associated with in-hospital mortality outcomes after elective AAA repair. Hospital case volume and practice patterns were also associated. This demonstrates the importance of adequate institutional experience with OAR techniques, which appear to be critically declining. Based on these data, appropriate patient selection and medical optimization appear to be the most important means by which we can improve outcomes following elective AAA repair, although patient referral to high-volume aortic centers of excellence should be a secondary consideration.

Contemporary Outcomes for Open Infrainguinal Bypass in the Endovascular Era

BACKGROUND The role of infrainguinal bypasses in this era of increasing endovascular interventions remains the subject of significant debate. In this study, we evaluate contemporary long-term outcomes of lower-extremity open revascularization for peripheral arterial disease (PAD). METHODS We evaluated all patients who underwent infrainguinal bypass with autogenous vein conduits for claudication or critical limb ischemia in our institution between January 1st, 2007 and July 31st, 2014. Kaplan-Meier and Cox regression analyses were used to evaluate graft failure and identify its predictors. Outcomes were defined per the Society for Vascular Surgery standards. RESULTS There were 428 autogenous vein grafts (femoro-popliteal: 32%, femoro-tibial: 39%, popliteo-tibial: 27%, and tibio-tibial: 2%) placed in 368 patients (mean age of 67 ± 11.4 years). Most patients were male (59%), white (73%), and presented with critical limb ischemia (81%). Sixty-five cases (15%) were redo bypasses. Arm veins and spliced vein conduits were used in 15% and 14% of cases, respectively. Primary patency at 1, 3, and 5 years was 66%, 59%, and 55%, respectively. Primary-assisted patency was 78%, 69%, and 64% at 1, 3, and 5 years, respectively. Secondary patency was 88%, 84%, and 82% at 1, 3, and 5 years, respectively. Patency was higher for grafts harvested from the lower versus upper extremities and for proximal versus distal bypass (all P < 0.05). Limb salvage rate was 88% after a mean follow-up of 2 ± 1.8 years. Significant predictors of graft failure were younger age, diabetes mellitus, and hyperlipidemia (all P < 0.05). CONCLUSIONS In this contemporary cohort of patients, we have demonstrated that infrainguinal bypass for lower-extremity revascularization has good long-term outcomes in patients with symptomatic PAD. Patency and limb salvage rates are optimized with careful selection of autogenous conduits, close monitoring of high-risk groups and management of comorbidities.