Tammam Obeid

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.

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.

The effect of ballooning following carotid stent deployment on hemodynamic stability.

OBJECTIVE While patient eligibility for carotid artery stenting (CAS) is well established, the intraoperative technique remains widely varied. The decision to perform poststent ballooning (PSB) is operator-dependent and often influenced by the interpretation of poststent angiography. While visually creating a greater luminal diameter, it is unclear whether PSB has immediate risks or long-term benefits. The purpose of this report is to determine whether PSB has any effects on periprocedural hemodynamic stability. METHODS A retrospective analysis of all patients that underwent CAS between 2005 and 2012 at a tertiary care center was performed. The primary end point was hemodynamic instability, defined as bradycardia (a heart rate of <60 beats/min) or hypotension (systolic blood pressure of <90 mm Hg) during the intraoperative or postoperative period. Binary logistic regression model was performed to determine the effect of PSB on the occurrence of hemodynamic instability, adjusting for patients age, sex, hypertension, diabetes mellitus, hyperlipidemia, coronary artery disease, recent myocardial infarction, previous carotid endarterectomy, high-risk status, and symptomatic status. RESULTS A total of 103 (51 men and 52 women) patients underwent placement of a unilateral carotid stent between 2005 and 2012 at our institution. All patients underwent prestent dilatation. However, 70% (n = 72) underwent PSB whereas 30% (n = 31) did not. PSB was a significant predictor of hemodynamic depression (odds ratio [OR], 3.8; 95% confidence interval, 1.3-11; P < .01). Symptomatic status, recent myocardial infarction, hyperlipidemia, and coronary artery disease were associated with a length of stay exceeding 24 hours postoperatively (OR, 6.6; P < .01, OR, 6.1; P < .01, OR, 5.4; P = .04, and OR, 9.3; P < .01, respectively). At follow-up, 97% (83/86) stents were patent. Two stent stenoses occurred in the group that received PSB, while one stent stenosis occurred in the group that did not receive PSB. CONCLUSIONS PSB increases the risk of intra- or postoperative hemodynamic depression in CAS and might increase the risk of major adverse cardiovascular events. Given the added complications and the lack of evidence supporting long term patency, PSB should be only selectively used.

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.

Beta-blocker use is associated with lower stroke and death after carotid artery stenting

BACKGROUND Proper selection of patients for carotid artery stenting (CAS) remains controversial despite multiple controlled trials. This relates in part to differences in interpretation of the relative importance of myocardial vs stroke complications after the procedure by different specialties and a lack of granular clinical data to analyze outcomes outside the large clinical trials. The objective of this study was to assess the effect of preoperative medications, procedure parameters, and patient characteristics on outcomes of CAS performed in a multispecialty national database. METHODS We analyzed all patients who underwent CAS between 2005 and 2014 in the Vascular Quality Initiative. A multivariate logistic regression model was built to assess the effects of age, gender, comorbidities, smoking, preprocedure medications, procedure details, and hypotension or hypertension that required intravenous medication on 30-day death or stroke rates. RESULTS A total of 5263 patients underwent CAS (mean age, 70 years; 63% male). The 30-day stroke/death rate was 3.4% (1.5% minor stroke, 0.9% major stroke, and 1.2% death; 40% of patients who had major strokes died within 30 days), and the myocardial infarction rate was 0.8%. Postprocedural hypertension requiring treatment occurred in 519 cases (9.9%), and it was associated with a 3.4-fold increase in stroke/death (odds ratio, 3.39; 95% confidence interval, 2.30-5.00; P < .0001). Preprocedural beta-blocker use for >30 days was associated with a 34% reduction in the stroke/death risk (odds ratio, 0.66; 95% confidence interval, 0.46-0.95; P = .025) compared with nonuse. Beta-blocker use was not associated with postprocedural hypotension. Other predictors of postoperative stroke and death included age, symptomatic status, diabetes (type 1 or type 2), and postprocedural hypotension, whereas prior carotid endarterectomy and distal embolic protection use were protective. CONCLUSIONS Postprocedural hypertension and hypotension that require treatment are both strongly associated with periprocedural stroke/death after CAS. Beta blockers significantly reduce the stroke/death risk associated with carotid stenting and should be investigated prospectively for potential use during CAS.

Quality Improvement Targets for Regional Variation in Surgical End-Stage Renal Disease Care

IMPORTANCE Arteriovenous fistula (AVF) access improves survival in patients with end-stage renal disease (ESRD) compared with other modalities when used at first hemodialysis. Use varies between locations, but, to our knowledge, no study has related this finding to mortality on a national scale. OBJECTIVE To quantify regional variation in AVF access at first hemodialysis, as well as the associated effect on mortality in the US Renal Data System. DESIGN, SETTING, AND PARTICIPANTS The US Renal Data System tracks all patients with ESRD in the United States. A retrospective analysis of the population from January 1, 2006, to December 31, 2010, was performed. Univariate analyses (χ² test; 2-tailed, unpaired t test; and analysis of variance) as well as multivariable logistic regressions were carried out to compare patient characteristics, incident AVF frequencies, and corrected mortality hazards between ESRD Network Programs, which comprise 18 states, commonwealths, and protectorates in which residents receive hemodialysis. Of the patients receiving hemodialysis in these networks, the data on 464,547 individuals who were beginning renal replacement therapy were analyzed. Analysis was started April 1, 2013, and ended August 3, 2014. MAIN OUTCOMES AND MEASURES Mortality hazard variation between ESRD Network Programs in the United States and incident AVF frequency. RESULTS Of the 464,547 patients beginning hemodialysis in this cohort, first hemodialysis with an AVF ranged from 11.1% to 22.2% depending on the ESRD Network in which they maintained residency (P < .001). Similarly, corrected mortality hazard varied by 28% (hazard ratios from 0.99 [95% CI, 0.96-1.03] to 1.27 [95% CI, 1.22-1.31]; P < .001). Logistic regression determined nephrology care to increase the odds of a patient beginning hemodialysis using an AVF by 11-fold (odds ratio, 11.42 [95% CI, 10.93-11.93]; P < .001); congestive heart failure was a negative correlatefold (odds ratio, 0.65 [95% CI, 0.64-0.67]; P < .001). No region achieved the 50% Fistula First Breakthrough Initiative (now known as Fistula First Catheter Last) target for incident AVF access. CONCLUSIONS AND RELEVANCE Marked regional variation in functional incident AVF frequency and risk-adjusted ESRD mortality exists across the United States. Differences in access to preoperative nephrology care and patient comorbidities may explain some of these variations, but an opportunity to implement best-practice guidelines exists.

Fixed and variable cost of carotid endarterectomy and stenting in the United States: A comparative study

Objective: Despite multiple landmark clinical trials, little data exists on real‐world cost of carotid artery stenting (CAS) and carotid endarterectomy (CEA) to the United States healthcare system. We aim to study differences in actual hospitalization cost between patients who underwent CAS vs CEA in a nationally representative database. Methods: We studied hospital discharge and billing records of all patients, in the Premier Perspective Database, who underwent CEA or CAS between the third quarter of 2009 and the first quarter of 2015. Nearest‐neighbor 1:1 propensity score matching was performed, to account for differences in patient and hospital characteristics as well as clinical comorbidities of patients who underwent both procedures, for both symptomatic and asymptomatic cohorts using 32 variables. Pearson χ2, Student t‐test, and nonparametric K‐sample equality‐of‐medians tests were used to analyze the data, as appropriate. The primary outcome was total in‐hospital cost, including fixed (administrative, capital and utilities) and variable costs (labor and supply). Cost data were presented as medians, inflation‐adjusted for 2015 U.S. dollar and rounded to the nearest dollar. Results: A total of 115,548 procedures were identified. The mean age was 71 and 69 years; 58% and 57% were male patients; and 81% and 77% were white among asymptomatic and symptomatic patients, respectively. After propensity score matching, 25,812 asymptomatic (12,906 CEA and 12,906 CAS) and 3864 symptomatic (1932 CEA and 1932 CAS) patients were included. Total hospitalization cost per CAS was 40% (