Contemporary Trends in Physician Utilization Rates of CEA and CAS for Asymptomatic Carotid Stenosis among Medicare Beneficiaries.

BACKGROUND: Carotid revascularization for asymptomatic carotid artery stenosis (ACAS) has become increasingly controversial in the past few decades as the best medical therapy has improved. The aim of this study was to assess and define contemporary trends in the rate of carotid revascularization procedures for ACAS in the United States and to characterize outlier physicians performing a higher rate of asymptomatic revascularization compared to their peers. METHODS: We used 100% Medicare fee-for-service claims to identify all patients who were newly diagnosed with ACAS between 01/2011-06/2018. Patients with symptomatic carotid artery stenosis, those with prior carotid revascularization, and surgeons who performed ≤10 CEAs during the study period were excluded. We used a hierarchical multivariable logistic regression model to evaluate patient and physician characteristics associated with undergoing a carotid endarterectomy or carotid artery stent procedure within 3 months after the initial diagnosis of ACAS. We also assessed temporal trends in carotid revascularization rates over time using the Cochran-Armitage Trend Test. RESULTS: Overall, 795,512 patients (median age 73.9 years, 50.9% male, 87.6% white) had a first-time diagnosis of ACAS during the study period, of which 23,481 (3.0%) underwent carotid revascularization within 3 months. There was a significant decline in overall carotid artery revascularization rates over time (2011: 3.2% vs. 2018: 2.1%; P < 0.001). The median and mean physician-specific carotid revascularization rates were 2.0% (IQR 0.0%-6.3%) and 4.7% ± 7.1%, respectively. Three-hundred and fifty physicians (5.2%) had carotid revascularization rates ≥19%, which was more than 2 standard deviations above the mean. After adjusting for patient-level characteristics, physician-level variables associated with carotid revascularization for newly diagnosed ACAS included male sex (adjusted OR 1.59, 95% CI 1.35-1.89), more years in practice (≥31 vs. <10 years, aOR 1.64, 95% CI 1.32-2.04), rural practice location (aOR 1.34, 95% CI 1.18-1.52), Southern region practice location (versus Northeast, aOR 1.54, 95% CI 1.39-1.69), and lower volume of ACAS patients (lower versus upper tertile, aOR 2.62, 95% CI 2.39-2.89). Cardiothoracic surgeons had a 1.52-fold higher odds of carotid revascularization compared to vascular surgeons (95% CI 1.36-1.68), whereas cardiologists and radiologists had lower intervention rates (both, P < 0.05). CONCLUSIONS: The current early revascularization rate for newly diagnosed ACAS is <5% among proceduralists in the United States, and has been decreasing steadily since 2014. There are particular physician-level characteristics that are associated with higher rates of carotid revascularization that cannot be fully contextualized without high-level contemporary outcomes data to guide decision making in ACAS.

Rectal Trauma: Evidence-Based Practices.

The management of rectal trauma has often been lumped in with colon trauma when, in fact, it is a unique entity. The anatomic nature of the rectum (with its intra- and extraperitoneal segments) lends itself to unique circumstances when it comes to management and treatment. From the four Ds (debridement, drainage, diversion, and distal irrigation), the management of rectal trauma has made some strides in light of the experiences coming out of the recent conflicts overseas as well as some rethinking of dogma. This article will serve to review the anatomy and types of injuries associated with rectal trauma. A treatment algorithm will also be presented based on our current literature review. We will also address controversial points and attempt to give our opinion in an effort to provide an update on an age-old problem.

Hemodynamic effects of the Abdominal Aortic and Junctional Tourniquet in a hemorrhagic swine model.

BACKGROUND: Torso hemorrhage constitutes a leading cause of battlefield mortality. The Abdominal Aortic and Junctional Tourniquet (AAJT) uses a pneumatic bladder to compress the aorta reducing pelvic and lower extremity perfusion; however, concern exists over the risk of caval compression exacerbating hypotension after application. METHODS: Male swine (70-90 kg) were randomized into four groups of 10: presence or absence of hemorrhage and AAJT placement. After a 40% hemorrhage, a 15-min period of hypovolemia was observed before the AAJT application. All animals received two 500 mL boluses of Hextend separated by 30 min. Cardiovascular, pulmonary, and oxygenation values were compared among groups. RESULTS: The AAJT was effective in reducing blood flow to the femoral arteries in both hemorrhaged and nonhemorrhaged animals (P < 0.001 for both groups). Hemorrhage resulted in significant decrease in mean arterial pressure compared with sham controls (23.5 ± 2.4 versus 61.6 ± 7.8 mm Hg, respectively, P < 0.001). AAJT application, compared with untreated controls, resulted in a significant increase in mean arterial pressure and systemic vascular resistance but not in cardiac output, oxygenation, and central venous pressure. Furthermore, no indication of overresuscitation injury was present as evidenced by pulmonary artery pressure and pulmonary histology. CONCLUSIONS: AAJT application in an animal model of severe shock results in a favorable hemodynamic profile because of afterload support. The present study did not demonstrate any adverse consequences because of caval compression, bowel injury, or pulmonary dysfunction. In addition, there does not appear to be any particular intravenous fluid economy achieved by AAJT application.

Antimicrobial-bonded graft patency in the setting of a polymicrobial infection in swine (Sus scrofa).

BACKGROUND: Polytetrafluoroethylene (PTFE) and Dacron are commonly used as arterial conduits in vascular trauma or infection when vein interposition graft may not be available. This study used a previously validated large animal model of polymicrobial infection to assess the patency and infectious resistance of a novel, antibiotic-impregnated graft material compared with PTFE and Dacron. METHODS: Forty-eight animals were placed into five groups for a 21-day survival period. A 6-mm PTFE, Dacron, or antimicrobial-bonded graft was used to replace the iliac artery and then inoculated with 1 × 107 colonies/mL of genetically labeled Pseudomonas aeruginosa and Staphylococcus aureus. Native vessels with and without contamination served as control groups. The primary end points were graft patency (determined by duplex ultrasound and necropsy) and graft infection (culture with molecular analysis). Secondary end points included physiologic measurements, blood cultures, laboratory data, and histopathology. RESULTS: At 21 days, 50% of PTFE, 62.5% of Dacron, and 100% of the antimicrobial-bonded grafts remained patent (P = .04). PTFE and Dacron had an equivalent number of overall infections, 87.5% and 75%, respectively (P = 1.0). There was no significant difference of infectious organisms between standard materials. The infection rate of the antimicrobial-bonded graft (25%) was significantly less than that of both PTFE and Dacron (P < .01), and all of these infections were secondary to P. aeruginosa. Clinical data did not vary significantly between groups. There were no mortalities in the protocol secondary to graft blowout or sepsis. CONCLUSIONS: The antimicrobial-bonded graft material outperformed standard PTFE and Dacron in the setting of polymicrobial infection with regard to graft patency and infection. The novel prosthetic material appears to be resistant to infection with S. aureus and to limit the growth of P. aeruginosa. Additional studies are recommended to explore the role of this antibiotic-bonded graft for use in the setting of vascular infection or trauma.

Quality of Life in United States Veterans With Combat-Related Ostomies From Iraq and Afghanistan.

OBJECTIVE: Assess the impact of ostomy formation on quality of life for U.S. Service Members. METHODS: U.S. personnel sustaining colorectal trauma from 2003 to 2011 were identified using the Department of Defense Trauma Registry. A cross-sectional observational study was conducted utilizing prospective interviews with standard survey instruments. Primary outcome measures were the Stoma Quality of Life Scale and Veterans RAND 36 scores and subjective responses. Patients with colorectal trauma not requiring ostomy served as controls. RESULTS: Of 177 available patients, 90 (50.8%) male veterans consented to participate (55 ostomy, 35 control). No significant differences were observed between ostomy and control groups for Injury Severity Score (25.6 ± 9.9 vs. 22.9 ± 11.8, p = 0.26) or mechanism of injury (blast: 55 vs. 52%, p = 0.75); nonostomates had fewer anorectal injuries (3.2 vs. 47.9%, p < 0.01). Median follow-up was 6.7 years. Veterans RAND-36 Physical and Mental Component Scores were similar between groups. About 45.8% of ostomates were willing-to-trade a median of 10 years (interquartile range = 5-15) of their remaining life for gastrointestinal continuity. At last follow-up, 95.9% of respondents' combat-related ostomies were reversed with a median duration of 6 (range = 3-19) months diverted. CONCLUSIONS: Ostomy creation in a combat environment remains safe and does not have a quantifiable impact on long-term quality of life.

Prosthetic Graft Patency in the Setting of a Polymicrobial Infection in Swine (Sus scrofa).

BACKGROUND: In the setting of vascular injury, vein interposition graft is the preferred conduit, but may have limited availability. This study seeks to develop a large animal model assessing the graft performance of polytetrafluoroethylene (PTFE) and Dacron in the setting of a polymicrobial infection. METHODS: Thirty-seven animals were placed into 4 groups for a 21-day survival period. Six-millimeter PTFE or Dacron interposition grafts were placed in the right iliac artery with a standardized bacterial inoculation. Native vessel with and without contamination served as control groups. The inoculant was 1 × 107 of genetically labeled Pseudomonas aeruginosa and Staphylococcus aureus. The primary end points were graft patency (determined by duplex ultrasound and necropsy) and graft infection (culture with molecular analysis). Secondary end points included physiological measurements, blood cultures, laboratory data, and histopathology. RESULTS: PTFE and Dacron had similar infection rates of 85.7% and 75%, respectively. There was no significant difference in infectious organisms between graft materials. PTFE and Dacron exhibited bacterial ingrowth and transmigration to the intraluminal portion of the conduit. Forty-five percent of the Dacron group and 40% of the PTFE group remained patent at postoperative day 21 (P = 0.98). Clinical data, including white blood cell count, percent neutrophils, and lactate, did not vary significantly between groups. CONCLUSIONS: PTFE and Dacron perform similarly in terms of infection rates and graft failure as both have a propensity toward bacterial ingrowth and occlusion when compared with controls. This is a valid animal model to assess graft performance in the setting of polymicrobial infection and provides an avenue for studying novel prosthetic conduits.

Rhabdomyolysis among critically ill combat casualties: Associations with acute kidney injury and mortality.

BACKGROUND: Rhabdomyolysis has been associated with poor outcomes in patients with traumatic injury, especially in the setting of acute kidney injury (AKI). However, rhabdomyolysis has not been systematically examined in a large cohort of combat casualties injured in the wars in Iraq and Afghanistan. METHODS: We conducted a retrospective study of casualties injured during combat operations in Iraq and Afghanistan who were initially admitted to the intensive care unit from February 1, 2002, to February 1, 2011. Information on age, sex, Abbreviated Injury Scale (AIS) score, Injury Severity Score (ISS), mechanism of injury, shock index, creatine kinase, and serum creatinine were collected. These variables were examined via multivariate logistic and Cox regression analyses to determine factors independently associated with rhabdomyolysis, AKI, and death. RESULTS: Of 6,011 admissions identified, a total of 2,109 patients met inclusion criteria and were included for analysis. Rhabdomyolysis, defined as creatine kinase greater than 5,000 U/L, was present in 656 subjects (31.1%). Risk factors for rhabdomyolysis identified on multivariable analysis included injuries to the abdomen and extremities, increased ISS, male sex, explosive mechanism of injury, and shock index greater than 0.9. After adjustment, patients with rhabdomyolysis had a greater than twofold increase in the odds of AKI. In the analysis for mortality, rhabdomyolysis was significantly associated with death until AKI was added, at which point it lost statistical significance. CONCLUSION: We found that rhabdomyolysis is associated with the development of AKI in combat casualties. While rhabdomyolysis was strongly associated with mortality on the univariate model and in conjunction with both ISS and age, it was not associated with mortality after the inclusion of AKI. This suggests that the effect of rhabdomyolysis on mortality may be mediated by AKI. LEVEL OF EVIDENCE: Prognostic and epidemiologic study, level III.

A diagnostic evolution: surgical experience with popliteal artery entrapment syndrome at a military tertiary referral center.

BACKGROUND: Popliteal artery entrapment syndrome (PAES) is an increasingly encountered disorder that typically presents as claudication in young and active individuals. However, despite the increased recognition, accurate preoperative diagnosis can be difficult. The objective of this study was to describe the surgical assessment and outcomes of patients treated for PAES. METHODS: Retrospective case series of all patients managed surgically for a diagnosis of PAES at the San Antonio Military Medical Center from 2005 to 2013. RESULTS: Over 8 years, PAES was surgically treated in 25 consecutive limbs of 15 patients (mean age, 35; range, 21-49) in a military tertiary medical center. Type III was the most common variant (n = 13, 52%), followed by type VI (n = 7, 28%). Most patients presented with class I or II ischemia (88%), with anterolateral symptoms (56%), and were referred by orthopedics (66%). Diagnostic work-up included stress ankle-brachial indices, magnetic resonance imaging (MRI) and provocative angiography. Sixty-three percent of limbs with negative MRI demonstrated findings consistent with either type III or V PAES. Tendon release was used in those with types III and V, whereas liberal myectomy was used in those with types I, II, or VI. Two patients required revascularization. At a median follow-up of 126 days (range, 25 days-7 years), 83% of patients with type III demonstrated partial resolution of symptoms. Only 27% of patients without an identifiable muscle slip had clinical improvement. CONCLUSIONS: Despite modern imaging, open surgical exploration remains the definitive diagnostic modality for PAES. Patients with a muscular or tendinous slip identified intraoperatively have the best clinical outcomes. Those with no identifiable muscle slip (functional entrapment) are less likely to demonstrate clinical improvement. Further evaluation on outcomes in the management in PAES is warranted.

A technique for endograft relining of a type IV endoleak using a surgeon-modified internal gate.

Type IV endoleaks represent a rare etiology of late endograft failure; however, depending on the location, they can be extremely challenging to repair with endovascular solutions. We present a method of endograft relining that preserves antegrade limb perfusion, avoids extra-anatomic reconstructions, and ensures complete endograft exclusion.

Mechanism of stent failure in a patient with fibromuscular dysplasia following renal artery stenting.

Endovascular techniques used in the management of renal artery stenosis (RAS) have unique complications, to include stent facture, thrombosis, aneurysm formation, migration, and in-stent restenosis. Described here is an unusual complication of renal artery obstruction and recurrent hypertension without progressive loss of renal function, secondary to intermittent arterial kinking with respiratory and cardiac motion in a patient with fibromuscular dysplasia. This mechanical complication has implication not only in successful endovascular treatment of RAS, but raises questions regarding the alterations in dynamic motion with the cardio-respiratory cycle in stented visceral arteries in other vascular pathologies requiring renal artery stenting (i.e., juxtarenal or pararenal aortic aneurysms).

Validation of the Short Musculoskeletal Function Assessment in patients with battlefield-related extremity vascular injuries.

OBJECTIVE: Vascular extremity injuries can be a significant burden on a patient's long-term quality of life. Currently, no limb-specific surveys have been used to quantify the relation between injury pattern and the resultant physical or psychological impact. The objective of this study was to validate the use of the Short Musculoskeletal Function Assessment (SMFA) in the setting of extremity vascular injury. METHODS: The Joint Theater Trauma Registry was queried and filtered for U.S. troops with an extremity vascular injury isolated to a single limb. Injury and management data were obtained, and the SMFA was administered after patient contact and consent. Validity was analyzed by characterization of SMFA score distribution, correlation with 36-Item Short Form Health Survey (SF-36) scores, and assessment of its discriminative capability to external measures of injury severity (ie, Injury Severity Score [ISS], Mangled Extremity Severity Score [MESS], and Medicare Part A disability qualification). RESULTS: At mean follow-up of 5 years, 164 patients (median age, 25 years; interquartile range, 22-31 years) completed both surveys. The overall SMFA Dysfunction Index was 24.8 ± 15.2 (range, 0-78; skewness, 0.60; floor/ceiling effect, 0%-1.2%; and nonresponse, 0%), and the overall Bother Index was 29.4 ± 20.2 (range, 0-96; skewness, 0.58; floor/ceiling effect, 0%-4.3%; and nonresponse, 0.6%). SF-36 physical component summary scores correlated inversely with the Dysfunction Index (r = -0.64; P < .01), whereas mental component summary scores correlated inversely with the Bother Index (r = -0.59; P < .01). No difference was found in reported scores between those considered severely injured (ISS > 15) and those not severely injured (ISS ≤ 15). However, those with mangled extremities (MESS ≥ 7) reported higher Dysfunction and Bother indices than those with lower scores (P < .05). In addition, patients considered disabled (per Medicare Part A qualifications) reported higher Dysfunction and Bother indices compared with those not considered disabled (P < .05). CONCLUSIONS: Use of the SMFA is validated in those with extremity vascular injuries, and it should be considered an adjunctive tool in evaluating long-term patient outcomes.

Magnetic resonance imaging: occult popliteal artery entrapment syndrome in a young soldier.

BACKGROUND: Popliteal artery entrapment syndrome (PAES) is frequently misdiagnosed because of symptom overlap with other conditions and lack of a definitive diagnostic modality. The incidence is widely variable, although it should be considered in all patients under 50 years with symptoms of lower extremity claudication. Long-term sequelae of PAES include critical limb ischemia, arterial occlusion, and aneurysm formation caused by repetitive external compression. METHODS: We review the case of a 27-year-old soldier originally treated for exertional compartment syndrome with fasciotomies without relief of symptoms. Magnetic resonance imaging (MRI) failed to demonstrate an aberrant slip of the gastrocnemius muscle, which was ultimately found and released on surgical exploration. RESULTS: Surgical exploration and release of an aberrant band of gastrocnemius muscle through a medial approach resulted in significant relief of symptoms and improvement of walking distance. CONCLUSIONS: Healthy athletes without peripheral vascular disease and symptomatic calf and foot claudication should have an early referral to vascular surgery. The risk of false-negative MRI warrants further investigation into provocative, noninvasive imaging modalities to properly classify PAES. This report reviews the literature to discuss the diagnostic challenges, natural history of disease, and surgical interventions for PAES.