Umair Qazi | Johns Hopkins University (original) (raw)

Papers by Umair Qazi

Research paper thumbnail of BRITISH MEDICAL JOURNALS

Research paper thumbnail of Racial Disparities after Vascular Trauma Are Age-Dependent

Journal of the American College of Surgeons, 2015

Research paper thumbnail of Performance of the Aorfix endograft in severely angulated proximal necks in the PYTHAGORAS United States clinical trial

Journal of vascular surgery, Jan 25, 2015

This study compared the performance of the Aorfix endograft (Lombard Medical, Oxfordshire, United... more This study compared the performance of the Aorfix endograft (Lombard Medical, Oxfordshire, United Kingdom) in standard (<60°), highly angled (60°-90°), and severely angled (>90°) aortic necks in the PYTHAGORAS study and evaluated changes in neck morphology over time. PYTHAGORAS is a prospective nonrandomized clinical trial of the Aorfix endograft. We divided the endovascular aneurysm repair (EVAR) cohort into groups by standard, high, and severe neck angle. The primary control group was patients concurrently undergoing open repair. Mortality at 30 days, 1 year, and 2 years and 30-day freedom from Society for Vascular Surgery major adverse events for the EVAR groups was compared with the open control. Aneurysm sac change, type I and III endoleaks, graft migration, and the reintervention rate at 1 and 2 years was compared between the standard, highly, and severely angled populations. The relative risk of graft complications with a neck diameter increase >10% was also calculat...

Research paper thumbnail of Stroke-2015-Malas-757-61

Research paper thumbnail of Vascular access modifies the protective effect of obesity on survival in hemodialysis patients

Surgery, 2015

The protective effect of obesity on the survival of patients undergoing hemodialysis (HD) for end... more The protective effect of obesity on the survival of patients undergoing hemodialysis (HD) for end-stage renal disease (ESRD), described as the obesity paradox, has been established previously. Survival benefits also have been ascribed to permanent modes of HD access (fistula/graft) compared with catheter at first HD. The purpose of this study is to evaluate the impact of incident HD access type on the obesity paradox. A retrospective study of all patients with ESRD in the US Renal Database System who initiated HD between 2006 and 2010 was carried out. Multivariate logistic, Cox regression, and propensity score matched analyses were used to evaluate the association between body mass index (BMI), modes of HD access (fistula/graft vs catheter), and mortality. There were 501,920 dialysis initiates studied; 83% via catheter, 14% via fistula, and 3% via grafts. Mortality was lesser for patients initiating hemodialysis with permanent forms of access compared with catheter (adjusted odds ratio 0.68, 95% confidence interval 0.67-0.69, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). High body mass index (BMI) was associated with lower mortality. Patients with high BMI were more likely to initiate hemodialysis via permanent modes of access compared with patients with normal BMI. The highly popularized protective effect of increased BMI on survival in HD patients is significantly influenced by the method of hemodialysis access. There is greater use of permanent access among patients with high BMI compared with patients with normal BMI. There remains a critical need to increase permanent access utilization at incident hemodialysis so as to improve survival irrespective of BMI status.

Research paper thumbnail of Quality Improvement Targets for Regional Variation in Surgical End-Stage Renal Disease Care

JAMA surgery, Jan 24, 2015

Arteriovenous fistula (AVF) access improves survival in patients with end-stage renal disease (ES... more 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. To quantify regional variation in AVF access at first hemodialysis, as well as the associated effect on mortality in the US Renal Data System. 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 re...

Research paper thumbnail of VH1. Sartorius Muscle Flap Closure of Infected Vascular Wound

Journal of Vascular Surgery, 2015

Research paper thumbnail of Hospital-Level Factors Associated With Mortality After Endovascular and Open Abdominal Aortic Aneurysm Repair

JAMA surgery, Jan 13, 2015

Endovascular technology has become ubiquitous in the modern care of abdominal aortic aneurysm (AA... more 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. To perform a preliminary analysis of hospital effects on mortality following open AAA repair (OAR) and endovascular AAA repair (EVAR). 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. 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). 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 wa...

Research paper thumbnail of The Age Effect In Increasing Operative Mortality Following Delay in Elective Abdominal Aortic Aneurysm Repair

Annals of vascular surgery, Jan 21, 2015

Elective repair of large Abdominal Aortic Aneurysms (AAA) is associated with the risk of signific... more Elective repair of large Abdominal Aortic Aneurysms (AAA) 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. We analyzed all patients in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) 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 post-operative mortality. There were 27,576 patients who underwent AAA repair during the study period (mean age 73.5years, SD 8.6; 80% male; 24% open repair). There wa...

Research paper thumbnail of Poststent ballooning is associated with increased periprocedural stroke and death rate in carotid artery stenting

Journal of vascular surgery, Jan 29, 2015

Whereas carotid endarterectomy (CEA) remains the "gold standard" treatment, given its l... more Whereas carotid endarterectomy (CEA) remains the "gold standard" treatment, given its low complication rate, carotid artery stenting (CAS) has emerged as a valid alternative in patients with prohibitive surgical risks. However, the application of CAS has been scrutinized, given its increased perioperative risk in comparison to CEA. Operators follow general guidelines in intraoperative techniques in CAS. However, few of those are evidence based. We believe that a specific outcome-driven examination of the effect of pre- and poststent deployment ballooning is warranted. The objective of this study was to analyze the effect of prestent ballooning (pre-SB) and poststent ballooning (post-SB) on hemodynamic depression (HD) and perioperative stroke or death. We performed a retrospective analysis of all patients who had CAS between 2005 and 2014 in the Vascular Quality Initiative database. Logistic regression analyses of the effect of different pre-SB and post-SB combinations on H...

Research paper thumbnail of Racial/Ethnic Disparities Associated With Initial Hemodialysis Access

JAMA Surgery, 2015

IMPORTANCE Superior outcomes have been established with the use of an arteriovenous fistula (AVF)... more 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.

Research paper thumbnail of Trends in Incident Hemodialysis Access and Mortality

JAMA Surgery, 2015

These principles, developed jointly by editorial and publishing staff, are applied by the America... more These principles, developed jointly by editorial and publishing staff, are applied by the American Medical Association (AMA) to ensure adherence to the highest ethical standards of advertising and to determine the eligibility of products and services for advertising in the AMA's print and digital publications.

Research paper thumbnail of Novel approach to a type I endoleak following a hybrid repair of an arch aortic aneurysm

Vascular and endovascular surgery

Hybrid surgical and endovascular approaches such as open visceral vessel debranching and subseque... more Hybrid surgical and endovascular approaches such as open visceral vessel debranching and subsequent endovascular exclusion of thoracic abdominal aortic aneurysms (TAAA) represents a significant development in treatment of TAAAs. As compared to traditional endovascular aneurysm repair, hybrid repairs commonly have a higher rate of endoleak and other endograft-related complications. In this report, we present a 71 year-old man with significant comorbidities including chronic obstructive pulmonary disease, hypertension and prostate cancer. The patient after undergoing debranching of the thoracic arch followed by endograft repair of an arch aneurysm developed a proximal type I and type II endoleak fed by the previously ligated left subclavian artery. Despite coiling of the left subclavian artery and proximal extension of the endograft, a type I endoleak persisted. Several months after the left subclavian artery was coiled, a catheter was advanced through the coils and beyond the site of...

Research paper thumbnail of Is endovascular stent-graft treatment of primary aortoesophageal fistula worthwhile?

Vascular and endovascular surgery, 2011

Aortoesophageal fistula (AEF) as a result of prolonged nasogastric intubation is rare and certain... more Aortoesophageal fistula (AEF) as a result of prolonged nasogastric intubation is rare and certainly fatal, without prompt surgical intervention. We report the case of a 41-year-old man with morbid obesity who was admitted after suffering 55% of total body surface area burns. After several skin graft operations over the course of 12 weeks, he was rushed into surgery because of the acute onset of severe upper gastrointestinal bleeding. Exploratory laparotomy and esophagogastroduodenoscopy (EGD) suggested an AEF, which was then quickly confirmed by a diagnostic angiogram. An endovascular aortic stent graft repair was performed that successfully stopped the bleeding. We include a review of the literature pertaining to cases of AEF treated by endovascular surgery, which appears to be a promising alternative to open surgery in the unfit patient.

Research paper thumbnail of The effect of ballooning following carotid stent deployment on hemodynamic stability

Journal of vascular surgery, 2014

While patient eligibility for carotid artery stenting (CAS) is well established, the intraoperati... more 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. 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 patient&#39...

Research paper thumbnail of Effect of Patching on Reducing Restenosis in the Carotid Revascularization Endarterectomy Versus Stenting Trial

Stroke; a journal of cerebral circulation, Jan 22, 2015

The purpose is to determine whether patching during carotid endarterectomy (CEA) affects the peri... more The purpose is to determine whether patching during carotid endarterectomy (CEA) affects the perioperative and long-term risks of restenosis, stroke, death, and myocardial infarction as compared with primary closure. We identified all patients who were randomized and underwent CEA in Carotid Revascularization Endarterectomy versus Stenting Trial. CEA patients who received a patch were compared with patients who underwent CEA with primary closure without a patch. We compared periprocedural and 4-year event rates, 2-year restenosis rates, and rates of reoperation between the 2 groups. We further analyzed results by surgeon specialty. There were 1151 patients who underwent CEA (753 [65%] with patch and 329 [29%] with primary closure). We excluded 44 patients who underwent eversion CEA and 25 patients missing CEA data (5%). Patch use differed by surgeon specialty: 89% of vascular surgeons, 6% of neurosurgeons, and 76% of thoracic surgeons patched. Comparing patients who received a patch...

Research paper thumbnail of Mortality benefits of different hemodialysis access types are age dependent

Journal of Vascular Surgery, 2015

Risk of death in dialysis patients is lowest with arteriovenous fistulas (AVFs), followed by arte... more 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. 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. 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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001) followed by AVGs (n = 17,543; aHR, 0.83; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). AVF was superior to both HC and AVG for all age groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;89 years, but AVG was superior to HC for patients 49 to 89 years of age (aHR, 0.811; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). The mortality benefit of AVF was consistently superior to that of AVG and HC for patients of all ages (all, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). AVF is superior to AVG and HC regardless of the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s age, including in octogenarians. In contrast, the mortality benefit of AVG over HC may not apply to younger (18-48 years) or older (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;89 years) age groups. All patients 18 to 48 years should receive AVF for dialysis access whenever possible.

Research paper thumbnail of Mortality variability after endovascular versus open abdominal aortic aneurysm repair in a large tertiary vascular center using a Medicare-derived risk prediction model

Journal of Vascular Surgery, 2015

Objective: Previous reports have documented better outcomes after open abdominal aortic aneurysm ... more Objective: Previous reports have documented better outcomes after open abdominal aortic aneurysm (AAA) repair in tertiary centers compared with lower-volume hospitals, but outcome variability for endovascular AAA repair (EVAR) vs open AAA repairs in a large tertiary center using a Medicare-derived mortality risk prediction model has not been previously reported. In the current study, we compared the observed vs predicted mortality after EVAR and open AAA repair in a single large tertiary vascular center. Methods: We retrospectively analyzed all patients who underwent repair of a nonruptured infrarenal AAA in our center from 2003 to 2012. Univariable and multivariable logistic regression were used to evaluate 30-day mortality. Patients were stratified into low-risk, medium-risk, and high-risk groups, and mortality was predicted for each patient based on demographics and comorbidities according to the Medicare risk prediction model. Results: We analyzed 297 patients (EVAR, 72%; open AAA repair, 28%; symptomatic, 25%). Most of our patients were of high and moderate risk (48% and 28%, respectively). The observed 30-day mortality was 1.9% after EVAR vs 2.4% after open repair (odds ratio [OR], 0.77; 95% confidence interval [CI], 0.14-4.29; P [ .67). There was no difference in mortality with EVAR vs open repair after adjusting for predefined patient characteristics (OR, 0.92; 95% CI, 0.16-7.43; P [ .93); only preoperative renal disease was predictive of 30-day mortality after AAA repair in our cohort (OR, 8.39; 95% CI, 1.41-67.0). The observed mortality within our study was significantly lower than the Medicare-derived expected mortality for each treatment group within patients stratified as high risk or medium risk (P # .0002 for all). Conclusions: Despite treating patients with high preoperative risk status, we report a 10-fold decrease in operative mortality for EVAR and open AAA repair in a tertiary vascular center compared with national Medicare-derived predictions. High-risk patients should be considered for aneurysm management in dedicated aortic centers, regardless of approach. (J Vasc Surg 2014;-:1-7.)

Research paper thumbnail of Design of the Revascularization With Open Bypass vs Angioplasty and Stenting of the Lower Extremity Trial (ROBUST)

JAMA Surgery, 2014

These principles, developed jointly by editorial and publishing staff, are applied by the America... more These principles, developed jointly by editorial and publishing staff, are applied by the American Medical Association (AMA) to ensure adherence to the highest ethical standards of advertising and to determine the eligibility of products and services for advertising in the AMA's print and digital publications.

Research paper thumbnail of Perioperative Mortality Following Repair of Abdominal Aortic Aneurysms

JAMA Surgery, 2014

Because of the restrictions applied to the conduct of randomized clinical trials, the risks repor... more 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. 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. 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. Death within 30 days of surgery. 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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). 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.

Research paper thumbnail of BRITISH MEDICAL JOURNALS

Research paper thumbnail of Racial Disparities after Vascular Trauma Are Age-Dependent

Journal of the American College of Surgeons, 2015

Research paper thumbnail of Performance of the Aorfix endograft in severely angulated proximal necks in the PYTHAGORAS United States clinical trial

Journal of vascular surgery, Jan 25, 2015

This study compared the performance of the Aorfix endograft (Lombard Medical, Oxfordshire, United... more This study compared the performance of the Aorfix endograft (Lombard Medical, Oxfordshire, United Kingdom) in standard (<60°), highly angled (60°-90°), and severely angled (>90°) aortic necks in the PYTHAGORAS study and evaluated changes in neck morphology over time. PYTHAGORAS is a prospective nonrandomized clinical trial of the Aorfix endograft. We divided the endovascular aneurysm repair (EVAR) cohort into groups by standard, high, and severe neck angle. The primary control group was patients concurrently undergoing open repair. Mortality at 30 days, 1 year, and 2 years and 30-day freedom from Society for Vascular Surgery major adverse events for the EVAR groups was compared with the open control. Aneurysm sac change, type I and III endoleaks, graft migration, and the reintervention rate at 1 and 2 years was compared between the standard, highly, and severely angled populations. The relative risk of graft complications with a neck diameter increase >10% was also calculat...

Research paper thumbnail of Stroke-2015-Malas-757-61

Research paper thumbnail of Vascular access modifies the protective effect of obesity on survival in hemodialysis patients

Surgery, 2015

The protective effect of obesity on the survival of patients undergoing hemodialysis (HD) for end... more The protective effect of obesity on the survival of patients undergoing hemodialysis (HD) for end-stage renal disease (ESRD), described as the obesity paradox, has been established previously. Survival benefits also have been ascribed to permanent modes of HD access (fistula/graft) compared with catheter at first HD. The purpose of this study is to evaluate the impact of incident HD access type on the obesity paradox. A retrospective study of all patients with ESRD in the US Renal Database System who initiated HD between 2006 and 2010 was carried out. Multivariate logistic, Cox regression, and propensity score matched analyses were used to evaluate the association between body mass index (BMI), modes of HD access (fistula/graft vs catheter), and mortality. There were 501,920 dialysis initiates studied; 83% via catheter, 14% via fistula, and 3% via grafts. Mortality was lesser for patients initiating hemodialysis with permanent forms of access compared with catheter (adjusted odds ratio 0.68, 95% confidence interval 0.67-0.69, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). High body mass index (BMI) was associated with lower mortality. Patients with high BMI were more likely to initiate hemodialysis via permanent modes of access compared with patients with normal BMI. The highly popularized protective effect of increased BMI on survival in HD patients is significantly influenced by the method of hemodialysis access. There is greater use of permanent access among patients with high BMI compared with patients with normal BMI. There remains a critical need to increase permanent access utilization at incident hemodialysis so as to improve survival irrespective of BMI status.

Research paper thumbnail of Quality Improvement Targets for Regional Variation in Surgical End-Stage Renal Disease Care

JAMA surgery, Jan 24, 2015

Arteriovenous fistula (AVF) access improves survival in patients with end-stage renal disease (ES... more 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. To quantify regional variation in AVF access at first hemodialysis, as well as the associated effect on mortality in the US Renal Data System. 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 re...

Research paper thumbnail of VH1. Sartorius Muscle Flap Closure of Infected Vascular Wound

Journal of Vascular Surgery, 2015

Research paper thumbnail of Hospital-Level Factors Associated With Mortality After Endovascular and Open Abdominal Aortic Aneurysm Repair

JAMA surgery, Jan 13, 2015

Endovascular technology has become ubiquitous in the modern care of abdominal aortic aneurysm (AA... more 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. To perform a preliminary analysis of hospital effects on mortality following open AAA repair (OAR) and endovascular AAA repair (EVAR). 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. 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). 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 wa...

Research paper thumbnail of The Age Effect In Increasing Operative Mortality Following Delay in Elective Abdominal Aortic Aneurysm Repair

Annals of vascular surgery, Jan 21, 2015

Elective repair of large Abdominal Aortic Aneurysms (AAA) is associated with the risk of signific... more Elective repair of large Abdominal Aortic Aneurysms (AAA) 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. We analyzed all patients in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) 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 post-operative mortality. There were 27,576 patients who underwent AAA repair during the study period (mean age 73.5years, SD 8.6; 80% male; 24% open repair). There wa...

Research paper thumbnail of Poststent ballooning is associated with increased periprocedural stroke and death rate in carotid artery stenting

Journal of vascular surgery, Jan 29, 2015

Whereas carotid endarterectomy (CEA) remains the "gold standard" treatment, given its l... more Whereas carotid endarterectomy (CEA) remains the "gold standard" treatment, given its low complication rate, carotid artery stenting (CAS) has emerged as a valid alternative in patients with prohibitive surgical risks. However, the application of CAS has been scrutinized, given its increased perioperative risk in comparison to CEA. Operators follow general guidelines in intraoperative techniques in CAS. However, few of those are evidence based. We believe that a specific outcome-driven examination of the effect of pre- and poststent deployment ballooning is warranted. The objective of this study was to analyze the effect of prestent ballooning (pre-SB) and poststent ballooning (post-SB) on hemodynamic depression (HD) and perioperative stroke or death. We performed a retrospective analysis of all patients who had CAS between 2005 and 2014 in the Vascular Quality Initiative database. Logistic regression analyses of the effect of different pre-SB and post-SB combinations on H...

Research paper thumbnail of Racial/Ethnic Disparities Associated With Initial Hemodialysis Access

JAMA Surgery, 2015

IMPORTANCE Superior outcomes have been established with the use of an arteriovenous fistula (AVF)... more 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.

Research paper thumbnail of Trends in Incident Hemodialysis Access and Mortality

JAMA Surgery, 2015

These principles, developed jointly by editorial and publishing staff, are applied by the America... more These principles, developed jointly by editorial and publishing staff, are applied by the American Medical Association (AMA) to ensure adherence to the highest ethical standards of advertising and to determine the eligibility of products and services for advertising in the AMA's print and digital publications.

Research paper thumbnail of Novel approach to a type I endoleak following a hybrid repair of an arch aortic aneurysm

Vascular and endovascular surgery

Hybrid surgical and endovascular approaches such as open visceral vessel debranching and subseque... more Hybrid surgical and endovascular approaches such as open visceral vessel debranching and subsequent endovascular exclusion of thoracic abdominal aortic aneurysms (TAAA) represents a significant development in treatment of TAAAs. As compared to traditional endovascular aneurysm repair, hybrid repairs commonly have a higher rate of endoleak and other endograft-related complications. In this report, we present a 71 year-old man with significant comorbidities including chronic obstructive pulmonary disease, hypertension and prostate cancer. The patient after undergoing debranching of the thoracic arch followed by endograft repair of an arch aneurysm developed a proximal type I and type II endoleak fed by the previously ligated left subclavian artery. Despite coiling of the left subclavian artery and proximal extension of the endograft, a type I endoleak persisted. Several months after the left subclavian artery was coiled, a catheter was advanced through the coils and beyond the site of...

Research paper thumbnail of Is endovascular stent-graft treatment of primary aortoesophageal fistula worthwhile?

Vascular and endovascular surgery, 2011

Aortoesophageal fistula (AEF) as a result of prolonged nasogastric intubation is rare and certain... more Aortoesophageal fistula (AEF) as a result of prolonged nasogastric intubation is rare and certainly fatal, without prompt surgical intervention. We report the case of a 41-year-old man with morbid obesity who was admitted after suffering 55% of total body surface area burns. After several skin graft operations over the course of 12 weeks, he was rushed into surgery because of the acute onset of severe upper gastrointestinal bleeding. Exploratory laparotomy and esophagogastroduodenoscopy (EGD) suggested an AEF, which was then quickly confirmed by a diagnostic angiogram. An endovascular aortic stent graft repair was performed that successfully stopped the bleeding. We include a review of the literature pertaining to cases of AEF treated by endovascular surgery, which appears to be a promising alternative to open surgery in the unfit patient.

Research paper thumbnail of The effect of ballooning following carotid stent deployment on hemodynamic stability

Journal of vascular surgery, 2014

While patient eligibility for carotid artery stenting (CAS) is well established, the intraoperati... more 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. 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 patient&#39...

Research paper thumbnail of Effect of Patching on Reducing Restenosis in the Carotid Revascularization Endarterectomy Versus Stenting Trial

Stroke; a journal of cerebral circulation, Jan 22, 2015

The purpose is to determine whether patching during carotid endarterectomy (CEA) affects the peri... more The purpose is to determine whether patching during carotid endarterectomy (CEA) affects the perioperative and long-term risks of restenosis, stroke, death, and myocardial infarction as compared with primary closure. We identified all patients who were randomized and underwent CEA in Carotid Revascularization Endarterectomy versus Stenting Trial. CEA patients who received a patch were compared with patients who underwent CEA with primary closure without a patch. We compared periprocedural and 4-year event rates, 2-year restenosis rates, and rates of reoperation between the 2 groups. We further analyzed results by surgeon specialty. There were 1151 patients who underwent CEA (753 [65%] with patch and 329 [29%] with primary closure). We excluded 44 patients who underwent eversion CEA and 25 patients missing CEA data (5%). Patch use differed by surgeon specialty: 89% of vascular surgeons, 6% of neurosurgeons, and 76% of thoracic surgeons patched. Comparing patients who received a patch...

Research paper thumbnail of Mortality benefits of different hemodialysis access types are age dependent

Journal of Vascular Surgery, 2015

Risk of death in dialysis patients is lowest with arteriovenous fistulas (AVFs), followed by arte... more 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. 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. 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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001) followed by AVGs (n = 17,543; aHR, 0.83; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). AVF was superior to both HC and AVG for all age groups (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;89 years, but AVG was superior to HC for patients 49 to 89 years of age (aHR, 0.811; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). The mortality benefit of AVF was consistently superior to that of AVG and HC for patients of all ages (all, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). AVF is superior to AVG and HC regardless of the patient&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s age, including in octogenarians. In contrast, the mortality benefit of AVG over HC may not apply to younger (18-48 years) or older (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;89 years) age groups. All patients 18 to 48 years should receive AVF for dialysis access whenever possible.

Research paper thumbnail of Mortality variability after endovascular versus open abdominal aortic aneurysm repair in a large tertiary vascular center using a Medicare-derived risk prediction model

Journal of Vascular Surgery, 2015

Objective: Previous reports have documented better outcomes after open abdominal aortic aneurysm ... more Objective: Previous reports have documented better outcomes after open abdominal aortic aneurysm (AAA) repair in tertiary centers compared with lower-volume hospitals, but outcome variability for endovascular AAA repair (EVAR) vs open AAA repairs in a large tertiary center using a Medicare-derived mortality risk prediction model has not been previously reported. In the current study, we compared the observed vs predicted mortality after EVAR and open AAA repair in a single large tertiary vascular center. Methods: We retrospectively analyzed all patients who underwent repair of a nonruptured infrarenal AAA in our center from 2003 to 2012. Univariable and multivariable logistic regression were used to evaluate 30-day mortality. Patients were stratified into low-risk, medium-risk, and high-risk groups, and mortality was predicted for each patient based on demographics and comorbidities according to the Medicare risk prediction model. Results: We analyzed 297 patients (EVAR, 72%; open AAA repair, 28%; symptomatic, 25%). Most of our patients were of high and moderate risk (48% and 28%, respectively). The observed 30-day mortality was 1.9% after EVAR vs 2.4% after open repair (odds ratio [OR], 0.77; 95% confidence interval [CI], 0.14-4.29; P [ .67). There was no difference in mortality with EVAR vs open repair after adjusting for predefined patient characteristics (OR, 0.92; 95% CI, 0.16-7.43; P [ .93); only preoperative renal disease was predictive of 30-day mortality after AAA repair in our cohort (OR, 8.39; 95% CI, 1.41-67.0). The observed mortality within our study was significantly lower than the Medicare-derived expected mortality for each treatment group within patients stratified as high risk or medium risk (P # .0002 for all). Conclusions: Despite treating patients with high preoperative risk status, we report a 10-fold decrease in operative mortality for EVAR and open AAA repair in a tertiary vascular center compared with national Medicare-derived predictions. High-risk patients should be considered for aneurysm management in dedicated aortic centers, regardless of approach. (J Vasc Surg 2014;-:1-7.)

Research paper thumbnail of Design of the Revascularization With Open Bypass vs Angioplasty and Stenting of the Lower Extremity Trial (ROBUST)

JAMA Surgery, 2014

These principles, developed jointly by editorial and publishing staff, are applied by the America... more These principles, developed jointly by editorial and publishing staff, are applied by the American Medical Association (AMA) to ensure adherence to the highest ethical standards of advertising and to determine the eligibility of products and services for advertising in the AMA's print and digital publications.

Research paper thumbnail of Perioperative Mortality Following Repair of Abdominal Aortic Aneurysms

JAMA Surgery, 2014

Because of the restrictions applied to the conduct of randomized clinical trials, the risks repor... more 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. 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. 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. Death within 30 days of surgery. 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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .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 &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; .05). 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.