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he value of perioperative chemoprophylaxis inolorectal surgeryung Kwon, Mark H Meissner, Rebecca G Symons MSniversity of Washington, Seattle, WA

NTRODUCTION: In patients having abdominal operations thetility of chemoprophylaxis for symptomatic deep vein thrombosisDVT), pulmonary embolisms (PEs), and mortality has not beenlearly demonstrated. Prior studies have used venography/ultrasoundesults as a surrogate marker of clinically relevant venothromboem-olic (VTE) events (DVT/PE) and there is skepticism about theroader use of chemoprophylaxis.

ETHODS: Surgical Care and Outcomes Assessment ProgramSCOAP) is a Washington State-based benchmarking QI initiativeased on chart-abstracted process of care and outcome data. Weompared the composite adverse event (CAE) rate [deaths and/orTE undergoing interventions (caval filter, new anticoagulation, re-

dmission)] within 30 days of discharge after elective, colon/rectalesections at 36 hospitals (2006-2009) based on receipt of perioper-tive chemoprophylaxis (within 24 hours).

ESULTS: Of 4195 (61.1�15.6 yrs; 54.1% women) patients,6.5% received perioperative chemoprophylaxis. The 30-day mor-ality rate (1.59% vs 0.76%), VTE with intervention (1.20% vs.59%) and CAE ( 2.96% vs 1.56%) were higher in those whoeceived no chemoprophylaxis compared to those who received peri-perative chemoprophylaxis (all p-values�0.05). After adjustmentor relevant patient and procedure characteristics the odds of a CAEere 50% lower if receiving perioperative chemoprophylaxis (OR.50, 95% Ci 0.30-0.86) with a number needed to treat of 69 tovoid one CAE.

ONCLUSIONS: Use of perioperative chemoprophylaxis was associ-ted with a lower rate of clinically significant VTE and death after colo-ectal resections. This appears to be the first study in modern era todentify a decrease in clinically relevant VTE endpoints and supports theroader use of chemoprophylaxis for patients having these operations.

atient-specific rehearsal of a carotid arterytenting procedure results in superior operativeerformance compared to a preoperative genericarm-upillem Willaert MD, Raj Aggarwal MD, PhD, Farhad Daruwalla BSc,

sabelle Van Herzeele MD, PhD, Frank Vermassen MD, PhD,ra W Darzi FRCS, FACS, MD, MedSci, Nick Cheshire MD, FRCSmperial College London, London, United Kingdom

NTRODUCTION: Patient-specific simulated rehearsal (PsR) of a ca-otid artery stenting procedure (CAS) allows incorporation of patient-pecific CT data into the simulation software, enabling the intervention-list to rehearse the case prior to the procedure on the actual patient.Thistudy aimed to evaluate whether PsR of a CAS procedure can enhanceperative performance compared to a virtual reality (VR) generic CASarm-up procedure or no preparation at all.

ETHODS: Participants were trained in CAS during a 10 session

ognitive/technical VR course. Thereafter, in a randomized crossover G

S1422010 by the American College of Surgeons

ublished by Elsevier Inc.

tudy, each participant performed a patient-specific CAS case 3 timesn the simulator, preceded by 3 different tasks: a PsR, a generic caser no preparation. Technical performances were assessed usingimulator-based metrics and expert-based ratings.

ESULTS: 20 medical trainees (surgery, cardiology, radiology) wereecruited. Training plateaus were observed after 10 sessions for allarticipants. PsR was significantly better than generic warm-up ando warm-up for total procedure time (15.8 vs. 18.7 vs. 19.4 min,�0.001) and fluoroscopy time (9.3 vs. 10.6 vs. 10.5 min, p�0.02)ut did not influence contrast volume or number of roadmaps useduring the ‘real’ case. PsR was significantly better at enhancing theuality of performance as measured by the expert-based ratings (score7 vs. 24 vs. 22, p�0.02).

ONCLUSIONS: Patient-specific simulated rehearsal of a CAS pro-edure significantly improves operative performance, compared to aeneric VR warm-up or no warm-up. This technology requires fur-her investigation with respect to improved outcomes on patients inhe clinical setting.

ssessing stroke risk in carotid stenting: Greycale median and debris analysis predict greaterisk for cerebral emboli in symptomatic patientshristine Chung BS, Ronald E Gordon PhD, Tejas R Shah MD,ichael L Marin MD, FACS, Peter L Faries MD, FACSount Sinai Medical Center, New York, NY

NTRODUCTION: Symptomatic patients undergoing carotid an-ioplasty and stenting (CAS) may possess greater embolic risk thansymptomatic patients. We seek to correlate plaque echolucency andicroscopic debris characteristics with plaque instability in symp-

omatic CAS patients.

ETHODS: 236 CAS procedures were performed between 2003-9.laque echomorphology of 42 consecutive patients was determinedy gray scale median (GSM) with image normalization (blood: GSM-5, adventitia: GSM 185-195). Echolucent (EL) and echogenicEG) plaques were defined by GSM�25 and GSM �25, respec-ively. Filters were visualized by photomicroscopy and quantifiedhrough imaging software. 24 filters underwent electron microscopyEM) to determine particulate components.

ESULTS: B-mode images for 21 patients (38% symptomatic) werenalyzed. Mean GSM was 45.4�15.3; 10% plaques were echolucent.laques with lower GSM were associated with greater particulate num-er (EL:33.5�10.6, EG:14.0�10.3; p�.02) and size (EL:3490�1954,G:1026�1186; p�.02). Mean GSM did not differ between symp-

omatic and asymptomatic groups (47.3�16.0, 44.4�15.4, respective-y; p�NS). Debris of 13 (54.2%) filters (7 symptomatic) demonstratedlaque and vessel wall components. All filters of symptomatic patientshowed neutrophils, macrophages, lymphocytes, lipids, activated plate-et thrombi, smooth muscle cells, and fibrin while all asymptomaticatients only contained a mixture of unactivated and activated platelethrombi, fibrin, and collagen.

ONCLUSIONS: Greater plaque echolucency may cause increasedmbolization during CAS, confirming prior findings that suggest a

SM cut-off of 25 for determining embolic potential. Furthermore,

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S143Vol. 211, No. 3S, September 2010 Surgical Forum Abstracts

ymptomatic patients may possess increased plaque inflammationnd activation than asymptomatic patients, suggesting that neuro-ogic symptoms may indicate the presence of unstable, vulnerablelaques prone to perioperative neurologic complications.

haracterization and outcomes of iliac vessel injuryn the 21st century: A review of the Nationalrauma Data Bankargaret Lauerman MD, Fernando Joglar MD, Denis Rybin MS,heorghe Doros PhD, Jeffrey Kalish MD, Naomi Hamburg MD,obert Eberhardt MD, Palma Shaw MD, Tony Nguyen MD,lik Farber MDoston University Medical Center, Boston, MA

NTRODUCTION: Iliac vessel trauma (IVT) has been historicallyssociated with significant morbidity and mortality. We evaluated aodern cohort of patients with IVT and assessed the effect of com-

ined arterial and venous injury on outcomes.

ETHODS: Using the National Trauma Data Bank (2002-2006)e identified patients with IVT. Demographics, injury characteris-

ics, treatments, complications, and outcomes were investigated. Pa-ients were stratified by mechanism and injury extent (artery alone,ein alone, and combined artery and vein).

ESULTS: There were 1,036 patients with IVT among 1,309,311ases. Penetrating and blunt trauma occurred in 616 (59.5%) and 42040.5%) patients, respectively. There were 550 arterial (53.1%), 303enous (29.2%), and 183 combined (17.7%) injuries. Open and endo-ascular repair occurred in 504 (48.6%) and 53 (5.1%) patients, respec-ively. Complications included deep vein thrombosis (DVT) in 585.6%), compartment syndrome in 48 (4.5%), and amputation in 383.7%) patients. Mortality rate was 32.7%. In penetrating trauma, ve-ous injury was associated with a higher DVT and lower mortality ratehan arterial injury (10.6% vs. 2.9%, p�.002 and 25.5% vs. 39.2%,�.002, respectively). Combined penetrating arterial and venous injuryas associated with higher DVT rate, fasciotomy rate, length of stay

LOS), and mortality than arterial injury alone (7.6% vs. 2.9%,p�.05;1.7% vs. 11.3%, p�.009; 17.9 vs. 11.6 days, p�.004; 51.6% vs.9.2%,p�.02, respectively). In multivariate analysis, addition of venousnjury to arterial injury significantly increased mortality and LOS.

ONCLUSIONS: Iliac vessel injury is associated with low limb re-ated morbidity and high mortality rates. Combined penetratingrterial and venous injury has higher complication and mortalityates than arterial injury alone.

ational trends and regional variation of open andndovascular repair of thoracic and thoracoabdominalortic aneurysms in contemporary practicealvatore T Scali MD, Salvatore T Scali MD,aniel B Walsh MD, FACS, Lori L Travis MS, Brian W Nolan MD,ichard J Powell MD, David C Goodman MD, MS,ee Lucas PhD, MS, Philip P Goodney MD, David H Stone MD, FACSartmouth-Hitchcock Medical Center, Lebanon, NH

NTRODUCTION: Historically, management of thoracic and thora-

oabdominal aneurysms has involved open surgical repair (OR). The 0

dvent and application of endovascular stent graft technologyTEVAR) to treat thoracic aortic pathology has become increasinglyommon in contemporary practice. To better determine the impactf TEVAR on OR, we herein examined national and regional trendsn treatment utilization.

ETHODS: Medicare patients from 1997-2007 undergoing iso-ated thoracic and thoracoabdominal aneurysm repair were analyzedsing a clinically validated algorithm utilizing diagnostic (ICD-941.1, 441.2, 441.6, 441.7, 441.9) and procedural (ICD9 38.35,8.45, 39.73, 39.79) codes. Differential rates of OR and TEVARere compared across census tract regions over the study interval.

ESULTS: Repairs increased by 60% from 10.8 to 17.8 per00,000 between 1997-2007 (p�0.001). While there was a dra-atic increase in TEVAR (not performed in 1997, 5.8 per 100,000

n 2007), OR rates remained stable during the study interval (10.7 to2.0 per 100,000 in 2007, p�NS) (Figure 1). There was substantialegional variation for both OR and TEVAR, however this was greatern OR (range 8.8 to 16.7 per 100,000) as compared to TEVARrange 4.5 to 6.9 per 100,000).

ONCLUSIONS: Repair rates for thoracic and thoracoabdominalneurysms increased from 1997-2007. This reflects the rapid spreadf TEVAR which appears to supplement rather than supplant OR,uggesting more patients are currently undergoing surgical treat-ent. Interestingly, there appears to be greater regional variation in

he application of OR versus TEVAR which may reflect the wide-pread adoption of TEVAR techniques across census tract regions.hese data may have significant implications in an era of supposedealth care cost containment.

upture risk of saccular descending thoracic aorticneurysms by stress modelingerek P Nathan MD, Chun Xu PhD, Clayton J Brinster MD,obert C Gorman MD, FACS, Joseph H Gorman III MD, FACS,enoit Desjardins MD PhD, Grace J Wang MD, Edward Y Woo MD,onald M Fairman MD, Benjamin M Jackson MS MDniversity of Pennsylvania, Philadelphia, PA

NTRODUCTION: Repair of fusiform descending thoracic aorticneurysms (FAs) is usually indicated when aneurysmal diameter ex-eeds a certain threshold. In contrast, indications for repair of saccu-ar aortic aneurysms (SAs) are less well-established. Using finite ele-

ent analysis (FEA), we compared the pressure-induced wall stress ofAs and SAs.

ETHODS: Human subjects with saccular (n�10) and fusiformn�10) aneurysms of the descending thoracic aorta underwent com-uted tomographic angiography. The thoracic aorta was segmented,econstructed, and triangulated to create a mesh. FEA was performedsing a pressure load of 120 mmHg and a uniform aortic wall thick-ess of 0.32 cm.

ESULTS: The mean maximum diameter of the SAs (4.7 �/� 1.4m) was significantly (P � 0.03) smaller than that of the FAs (6.3/� 1.7 cm). However, mean peak wall stress of the SAs (0.30 �/�

.13 MPa) was equivalent to mean peak wall stress of the FAs (0.38