Dejah R. Judelson

Outcomes of lower extremity bypass performed for acute limb ischemia

OBJECTIVE Acute limb ischemia remains one of the most challenging emergencies in vascular surgery. Historically, outcomes following interventions for acute limb ischemia have been associated with high rates of morbidity and mortality. The purpose of this study was to determine contemporary outcomes following lower extremity bypass performed for acute limb ischemia. METHODS All patients undergoing infrainguinal lower extremity bypass between 2003 and 2011 within hospitals comprising the Vascular Study Group of New England were identified. Patients were stratified according to whether or not the indication for lower extremity bypass was acute limb ischemia. Primary end points included bypass graft occlusion, major amputation, and mortality at 1 year postoperatively as determined by Kaplan-Meier life table analysis. Multivariable Cox proportional hazards models were constructed to evaluate independent predictors of mortality and major amputation at 1 year. RESULTS Of 5712 lower extremity bypass procedures, 323 (5.7%) were performed for acute limb ischemia. Patients undergoing lower extremity bypass for acute limb ischemia were similar in age (66 vs 67; P = .084) and sex (68% male vs 69% male; P = .617) compared with chronic ischemia patients, but were less likely to be on aspirin (63% vs 75%; P < .0001) or a statin (55% vs 68%; P < .0001). Patients with acute limb ischemia were more likely to be current smokers (49% vs 39%; P < .0001), to have had a prior ipsilateral bypass (33% vs 24%; P = .004) or a prior ipsilateral percutaneous intervention (41% vs 29%; P = .001). Bypasses performed for acute limb ischemia were longer in duration (270 vs 244 minutes; P = .007), had greater blood loss (363 vs 272 mL; P < .0001), and more commonly utilized prosthetic conduits (41% vs 33%; P = .003). Acute limb ischemia patients experienced increased in-hospital major adverse events (20% vs 12%; P < .0001) including myocardial infarction, congestive heart failure exacerbation, deterioration in renal function, and respiratory complications. Patients who underwent lower extremity bypass for acute limb ischemia had no difference in rates of graft occlusion (18.1% vs 18.5%; P = .77), but did have significantly higher rates of limb loss (22.4% vs 9.7%; P < .0001) and mortality (20.9% vs 13.1%; P < .0001) at 1 year. On multivariable analysis, acute limb ischemia was an independent predictor of both major amputation (hazard ratio, 2.16; confidence interval, 1.38-3.40; P = .001) and mortality (hazard ratio, 1.41; confidence interval, 1.09-1.83; P = .009) at 1 year. CONCLUSIONS Patients who present with acute limb ischemia represent a less medically optimized subgroup within the population of patients undergoing lower extremity bypass. These patients may be expected to have more complex operations followed by increased rates of perioperative adverse events. Additionally, despite equivalent graft patency rates, patients undergoing lower extremity bypass for acute ischemia have significantly higher rates of major amputation and mortality at 1 year.

ABT-869 Inhibits the Proliferation of Ewing Sarcoma Cells and Suppresses Platelet-Derived Growth Factor Receptor β and c-KIT Signaling Pathways

The Ewing Sarcoma (EWS) family of tumors is one of the most common tumors diagnosed in children and adolescents and is characterized by a translocation involving the EWS gene. Despite advances in chemotherapy, the prognosis of metastatic EWS is poor with an overall survival of <30% after 5 years. EWS tumor cells express the receptor tyrosine kinases, platelet-derived growth factor receptor (PDGFR) and c-KIT. ABT-869 is a multitargeted small-molecule inhibitor that targets Fms-like tyrosine kinase-3, c-KIT, vascular endothelial growth receptors, and PDGFRs. To determine the potential therapeutic benefit of ABT-869 in EWS cells, we examined the effects of ABT-869 on EWS cell lines and xenograft mouse models. ABT-869 inhibited the proliferation of two EWS cell lines, A4573 and TC71, at an IC50 of 1.25 and 2 μmol/L after 72 h of treatment, respectively. The phosphorylation of PDGFRβ, c-KIT, and extracellular signal-regulated kinases was also inhibited. To examine the effects of ABT-869 in vivo, the drug was given to mice injected with EWS cells. We observed inhibition of growth of EWS tumor cells in a xenograft mouse model and prolonged survival in a metastatic mouse model of EWS. Therefore, our in vitro and in vivo studies show that ABT-869 inhibits proliferation of EWS cells through inhibition of PDGFRβ and c-KIT pathways. Mol Cancer Ther; 9(3); 653–60

Budd-Chiari syndrome and post-traumatic diaphragmatic hernia

Diaphragmatic hernias occur in as many as 6% of patients after thoracoabdominal trauma, with the majority occurring on the left side as a result of the cushioning effects of the liver. Diagnosis is delayed in as many as 60% of all cases, and symptoms are nonspecific and include abdominal pain, shortness of breath, chest pain, cough, and tachypnea. We report a patient with chronic hepatothorax resulting from a right-sided diaphragmatic rupture after a remote history of blunt trauma more than 20 years previously presenting with irreversible Budd-Chiari syndrome in the right liver.

Peripheral atherectomy practice patterns in the United States from the Vascular Quality Initiative

Objective: Peripheral atherectomy has been shown to have technical success in single‐arm studies, but clinical advantages over angioplasty and stenting have not been demonstrated, leaving its role unclear. We sought to describe patterns of atherectomy use in a real‐world U.S. cohort to understand how it is currently being applied. Methods: The Vascular Quality Initiative was queried to identify all patients who underwent peripheral vascular intervention from January 2010 to September 2016. Descriptive statistics were performed to analyze demographics of the patients, comorbidities, indication, treatment modalities, and lesion characteristics. The intermittent claudication (IC) and critical limb ischemia (CLI) cohorts were analyzed separately. Results: Of 85,605 limbs treated, treatment indication was IC in 51% (n = 43,506) and CLI in 49% (n = 42,099). Atherectomy was used in 15% (n = 13,092) of cases, equivalently for IC (15%; n = 6674) and CLI (15%; n = 6418). There was regional variation in use of atherectomy, ranging from a low of 0% in one region to a high of 32% in another region. During the study period, there was a significant increase in the proportion of cases that used atherectomy (11% in 2010 vs 18% in 2016; P < .0001). Compared with nonatherectomy cases, those with atherectomy use had higher incidence of prior peripheral vascular intervention (IC, 55% vs 43% [P < .0001]; CLI, 47% vs 41% [P < .0001]), greater mean number of arteries treated (IC, 1.8 vs 1.6 [P < .0001]; CLI, 2.1 vs 1.7 [P < .0001]), and lower proportion of prior leg bypass (IC, 10% vs 14% [P < .0001]; CLI, 11% vs 17% [P < .0001]). There was lower incidence of failure to cross the lesion (IC, 1% vs 4% [P < .0001]; CLI, 4% vs 7% [P < .0001]) but higher incidence of distal embolization (IC, 1.9% vs 0.8% [P < .0001]; CLI, 3.0% vs 1.4% [P < .0001]) and, in the CLI cohort, arterial perforation (1.4% vs 1.0%; P = .01). Conclusions: Despite a lack of evidence for atherectomy over angioplasty and stenting, its use has increased across the United States from 2010 to 2016. It is applied equally to IC and CLI populations, with no identifiable pattern of comorbidities or lesion characteristics, suggesting that indications are not clearly delineated or agreed on. This study places impetus on further understanding of the optimal role for atherectomy and its long‐term clinical benefit in the management of peripheral arterial disease.

C10: Poster CompetitionPC094 Increasing the Number of Integrated Vascular Surgery Residency Positions Is Necessary to Address the Impending Shortage of Vascular Surgeons in the United States

three-dimensional (3D) printed aortic model connected to hemodynamic pump. Methods: The study was a prospective validation of EVAR simulation using a 3D printed photopolymer aortic model (Objet500 Connex3 printer; Stratasys, Eden Prairie, Minn) connected to BDC PD-0500 fluid pump (BDC Laboratories, Wheat Ridge, Colo). EVAR procedure metrics were benchmarked in two expert implanters and compared to 20 vascular surgical trainees with different levels of EVAR experience (<20 or >20 cases). All procedures were performed using commercially available stent grafts, fluoroscopic guidance, and high-fidelity simulation of procedural steps with guidewires, catheters, and contrast angiography (Fig). End points included ability to complete the procedure independently and time to deploy aortic component, cannulate the contralateral (CL) gate and complete the repair, total fluoroscopy time, and estimated distance from lowest renal artery. Results: Trainee experience with EVAR prior to the first simulation session was fewer than 5 in 7 trainees, 6 to 20 in 6 and 20 in 7. A total of 22 EVAR simulation procedures were performed by trainees with mean total procedure time of 37 6 12 minutes. Experienced trainees had significantly (P < .003) lower total procedural time (32 6 9 vs 44 6 6 minutes), fluoroscopic time (13 6 5 vs 23 6 8 minutes), and lag time between steps (5 6 2 vs 7 6 2 minutes). All experienced trainees completed the procedure independently in <45 minutes, compared to six (46%) of those with less EVAR experience (P 1⁄4 .016). Among less experienced trainees, only two (15%) completed the entire procedure independently (P < .001). Expert implanters performed significantly better than both trainee groups in nearly all EVAR metrics (Table). Conclusions: EVAR simulation with 3D printed aortic models and hemodynamic pump was feasible and simulated all procedural steps with high fidelity. This model may be applicable for assessment of technical competencies and standard endovascular skill acquisition within vascular surgery training curricula.

SS27 A Physician-Led Initiative to Improve Clinical Documentation Results in Improved Case-Mix Index and Increased Contribution Margin

mean of 167 days after stenting. Mean poststenting GFR and creatinine were 59 (range, 42-60) and 0.8 (range, 0.5-1.7). There was no difference betweenmean prestenting and poststenting GFR (P 1⁄4 .32) or creatinine (P 1⁄4 .41). Mean poststenting GFR and creatinine in the Wallstent, Z-stent, “renal gap,” and iliac vein only stents patients were: 60 and 0.9, 60 and 0.8, 60 and 0.7, and 59 and 0.8, respectively. There were no differences in poststenting mean GFR or creatinine between the Wallstent (P 1⁄4 .23; P 1⁄4 .27), Z-stent (P 1⁄4 .18; P 1⁄4 .32), and “renal gap” (P 1⁄4 .25; P 1⁄4 .15), and iliac vein only stent groups. One patient (1%) developed renal vein thrombosis treated with thrombolysis and stenting. Thirty patients (77%) with stents across the renal veins had follow-up imaging and all 30 (100%) had patent renal veins. Conclusions: Renal vein confluence stenting with small and large lattice stents does not compromise renal function or renal vein patency and may be performed when clinically indicated with few complications.

Increasing the number of integrated vascular surgery residency positions is important to address the impending shortage of vascular surgeons in the United States

Objective: The demand for vascular surgeons is expected to far exceed the current supply. In an attempt to decrease the training duration and to address the impending shortage, integrated vascular surgery residencies were approved and have expanded nationally. Meanwhile, vascular fellowships have continued to matriculate approximately 120 trainees annually. We sought to evaluate the supply and demand for integrated vascular residency positions as well as changes in the quality of applicants. Methods: We conducted a retrospective review of national data compiled by the Association of American Medical Colleges and the National Resident Matching Program regarding integrated vascular surgery residency programs (2008‐2015) and fellowships (2007‐2016). Variables reviewed included the total number of applicants, sex, U.S. vs international medical school enrollment, applications per program, and applicants per position. In addition, we conducted a retrospective review of applicants to the University of Massachusetts Medical School integrated vascular surgery residency program from 2008 to 2015 to examine these variables and United States Medical Licensing Examination Step 1 and Step 2 CK scores over time. Results: The number of vascular surgery integrated residency positions increased from 4 in 2008 to 56 in 2015. Concurrently, the number of integrated residency applicants grew from 112 in 2008 to 434 in 2015. This increase has been predominantly driven by a 575% increase in U.S. graduate applicants and a 170% increase in women applicants. The percentage of international medical graduates has decreased by 17% during the study period. The total number of applicants per residency position increased from 5.9 to 7.8. Meanwhile, the number of vascular surgery fellowship positions remained stable with an applicant to position ratio near 1:1. At the University of Massachusetts Medical School, the mean United States Medical Licensing Examination Step 1 (226 to 235) and Step 2 CK (237 to 243) scores among integrated residency applicants have improved annually and typically exceed the national average among U.S. applicants who have matched in their preferred specialty. Conclusions: Since the approval of a primary certificate in vascular surgery and the subsequent rollout of integrated vascular residency programs, the number of residency programs and the quality of residency applicants have continued to increase. Demand from medical school applicants vastly outweighs the current supply of training positions by eightfold. In contrast, demand from fellowship applicants matches the supply of fellowship positions. The matriculation of additional trainees must be met with continued expansion of the integrated vascular surgery residency pathway to manage future public health needs.