Evaluation of vascular repair by tissue-engineered human acellular vessels or expanded polytetrafluoroethylene grafts in a porcine model of limb ischemia and reperfusion.

BACKGROUND: This study evaluated performance of a tissue-engineered human acellular vessel (HAV) in a porcine model of acute vascular injury and ischemia. The HAV is an engineered blood vessel consisted of human vascular extracellular matrix proteins. Limb reperfusion and vascular outcomes of the HAV were compared with those from synthetic expanded polytetrafluoroethylene (ePTFE) grafts. METHODS: Thirty-six pigs were randomly assigned to four treatment groups, receiving either the HAV or a PTFE graft following a hind limb ischemia period of either 0 or 6 hours. All grafts were 3-cm-long interposition 6-mm diameter grafts implanted within the right iliac artery. Animals were not immunosuppressed and followed for up to 28 days after surgery. Assessments performed preoperatively and postoperatively included evaluation of graft patency, hind limb function, and biochemical markers of tissue ischemia or reperfusion injury. Histological analysis was performed on explants to assess host cell responses. RESULTS: Postoperative gait assessment and biochemical analysis confirmed that ischemia and reperfusion injury were caused by 6-hour ischemia, regardless of vascular graft type. Hind limb function and tissue damage biomarkers improved in all groups postoperatively. Final patency rates at postoperative day 28 were higher for HAV than for ePTFE graft in both the 0-hour (HAV, 85.7%; ePTFE, 66.7%) and 6-hour (HAV, 100%; ePTFE, 75%) ischemia groups, but these differences were not statistically significant. Histological analyses identified some intimal hyperplasia and host reactivity to the xenogeneic HAV and also to the synthetic ePTFE graft. Positive host integration and vascular cell infiltration were identified in HAV but not ePTFE explants. CONCLUSION: Based on the functional performance and the histologic profile of explanted HAVs, this study supports further investigation to evaluate long-term performance of the HAV when used to repair traumatic vascular injuries.

Aortic aneurysm screening using duplex ultrasound: Choosing wisely who to examine.

The noninvasive vascular laboratory plays a critical role in screening patients at risk for development of abdominal aortic aneurysm (AAA). One-time duplex ultrasound screening reduces aneurysm-related mortality due to rupture and is cost-effective. Population screening based on AAA risk factors is recommended, as it allows for proactive, elective repair of aneurysms at risk for rupture, and surveillance of smaller aneurysms for enlargement. Utilization of societal screening guidelines, such as those published by the Society for Vascular Surgery, can be employed by vascular laboratories to justify individual patient screening, aid primary care physicians to refer patients for testing, and encourage integrated medical health care systems to build prompts in patient electronic health records to ensure compliance with a AAA screening program. Risk factors for developing AAA, that is, age older than 65 years, male sex, family history, and a smoking history of >100 cigarettes, should be used to recommend patient screening, including for women and other elderly (older than 75 years) patients who fall outside of professional societal guidelines.

Management of Chronic Massive Traumatic Popliteal Artery Pseudoaneurysm: A Case Series With Different Treatment Strategies.

Giant traumatic popliteal artery (PA) pseudoaneurysms (PSA) are rare but limb threatening if untreated. Management can be challenging, as no standardized approach exists. This report evaluates our experience with 3 cases treated differently. Treatment is individualized based on patient disease and comorbidities. Endovascular and local patch arterial repair are safe alternatives to graft bypass when feasible.

Novel, non-gadolinium-enhanced magnetic resonance imaging technique of pedal artery aneurysms.

Non-gadolinium-enhanced magnetic resonance angiography (nMRA) is a noninvasive, contrast-free imaging modality used for visualizing pedal arterial anatomy. We report application of the nMRA technique for detailed arterial imaging in a patient with dorsalis pedis aneurysm. Compared with digital subtraction angiography, we demonstrate that nMRA provides sufficient arterial detail needed to develop a complex operative plan before vascular intervention without risk of contrast agent or ionizing radiation exposure.

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.

A retrospective cohort comparison of expanded polytetrafluorethylene to autologous vein for vascular reconstruction in modern combat casualty care.

BACKGROUND: Reconstruction of vascular injury often requires use of a conduit, either autologous vein (AV) or expanded polytetrafluorethylene (ePTFE). The most common anatomic locations for and durability of ePTFE as an adjunct to vascular repair in the combat setting are unknown. The objectives of this study were to characterize the anatomic locations of use of ePTFE during the wars in Afghanistan and Iraq and to compare its effectiveness to AV. METHODS: US service personnel undergoing vascular repair (2002-2012) were identified. Patients in whom ePTFE was used as an interposition conduit (n = 25) were matched with similar patients who received AV (n = 24) reconstruction. Injury and operative factors were assessed, and freedom from graft-related complication was quantified using Kaplan-Meier log-rank test. RESULTS: There was no difference between ePTFE and AV with regard to age, injury severity, or mangled extremity severity score. Follow-up for the ePTFE and AV groups was 71 and 62 months, respectively. In the cohort there was an apparent but not significantly greater freedom from graft-related complication for AV compared with ePTFE (65% vs. 17%; P = 0.13). In the carotid, subclavian, and axillary artery positions, ePTFE performed equal to AV with no apparent difference in freedom from graft-related complications (P = 0.90). However, in the periphery, AV demonstrated greater 8-year freedom from graft-related complication than ePTFE (77% vs. 31%, P = 0.044). CONCLUSIONS: AV is a more durable conduit than ePTFE in repair of wartime extremity vascular injury, whereas ePTFE is effective and durable in the carotid, subclavian, and axillary locations.

Functional outcome after resuscitative endovascular balloon occlusion of the aorta of the proximal and distal thoracic aorta in a swine model of controlled hemorrhage.

BACKGROUND: Noncompressible torso hemorrhage remains an ongoing problem for both military and civilian trauma. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been characterized as a potentially life-saving maneuver. The objective of this study was to determine the functional outcomes, paraplegia rates, and survival of 60-min balloon occlusion in the proximal and distal thoracic aorta in a porcine model of controlled hemorrhage. METHODS: Swine (Sus scrofa, 70-110 kg) were subjected to class IV hemorrhagic shock and underwent 60 min of REBOA. Devices were introduced from the left carotid artery and positioned in the thoracic aorta in either the proximal location (pREBOA [n = 8]; just past takeoff of left subclavian artery) or distal location (dREBOA [n = 8]; just above diaphragm). After REBOA, animals were resuscitated with whole blood, crystalloid, and vasopressors before a 4-day postoperative period. End points included evidence of spinal cord ischemia (clinical examination, Tarlov gait score, bowel and bladder dysfunction, and histopathology), gross ischemia-reperfusion injury (clinical examination and histopathology), and mortality. RESULTS: The overall mortality was similar between pREBOA and dREBOA groups at 37.5% (n = 3). Spinal cord-related mortality was 12.5% for both pREBOA and dREBOA groups. Spinal cord symptoms without death were present in 12.5% of pREBOA and dREBOA groups. Average gait scores improved throughout the postoperative period. CONCLUSIONS: REBOA placement in the proximal or distal thoracic aorta does not alter mortality or paraplegia rates as compared with controlled hemorrhage alone. Functional recovery improves in the presence or the absence of REBOA, although at a slower rate after REBOA as compared with negative controls. Additional research is required to determine the ideal placement of REBOA in an uncontrolled hemorrhage model to achieve use compatible with survival outcomes and quality of life.

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.

Initial management and outcome of modern battlefield anal trauma.

BACKGROUND: Despite the potential for morbidity and permanent lifestyle alteration, few reports exist examining traumatic injury to the anal canal, particularly among modern-day combatants. OBJECTIVE: The aim of this study was to document the incidence, initial surgical management, and long-term outcomes of wartime anal trauma. DESIGN: This study is a retrospective review. DATA SOURCES: Data were compiled from multiple electronic medical record systems, including the Department of Defense Trauma Registry, the Patient Administration Systems and Biostatistics Activity, and the Armed Forces Health Longitudinal Tracking Application. SETTINGS: Combatants were treated at military treatment facilities with surgical capability during the wars in Iraq and Afghanistan, 2003 through early 2011. PATIENTS: All US and coalition combatants sustaining trauma to the anal canal or sphincter musculature were included. MAIN OUTCOME MEASURES: The quantification of incidence, the evaluation of initial treatment approach, and the determination of clinical and surgical factors correlating with restoration or preservation of GI tract continuity were the primary outcomes measured. RESULTS: Anal trauma occurred in 46 combatants, predominantly from blast injury (76.1%). Most (36, 78.2%) underwent fecal diversion. Concurrent severe systemic or intra-abdominal injuries correlated with colostomy creation. Acute anoplasty was attempted in 11 patients (23.7%) but did not influence eventual colostomy reversal. Among 33 US personnel, the permanent colostomy rate was 30.3%. Concurrent injury to the abdomen strongly predicted long-term colostomy (p = 0.009), along with hypogastric arterial ligation (p = 0.05) and pelvic fracture (p = 0.06). LIMITATIONS: This study was limited by the potential underdiagnosis of anal injury and the restricted follow-up of non-US personnel. CONCLUSIONS: Other injuries besides anal trauma typically have guided the decision for fecal diversion, and acute anal repair has rarely been indicated. The majority of patients with anal trauma regained normal GI continuity, although certain pelvic injuries increased the likelihood of permanent colostomy.

Risk factors for colostomy in military colorectal trauma: a review of 867 patients.

BACKGROUND: Limited data exist examining the use of fecal diversion in combatants from modern armed conflicts. Characterization of factors leading to colostomy creation is an initial step toward optimizing and individualizing combat casualty care. METHODS: A retrospective review of the US Department of Defense Trauma Registry database was performed for all US and coalition troops with colorectal injuries sustained during combat operations in Iraq and Afghanistan over 8 years. Colostomy rate, anatomic injury location, mechanism of injury, demographic data, and initial physiologic parameters were examined. Univariate and multivariate analyses were conducted. RESULTS: We identified 867 coalition military personnel with colorectal injuries. The overall colostomy rate was 37%. Rectal injuries had the highest diversion rate (56%), followed by left-sided (41%) and right-sided (20%) locations (P < .0001). Those with gunshot wounds (GSW) underwent diversion more often than blast injuries (43% vs 31% respectively, P < .0008). Injury Severity Score ≥16 (41% vs 30%; P = .0018) and damage control surgery (DCS; 48.2% vs 31.4%; P < .0001) were associated with higher diversion rates. On multivariate analysis, significant predictors for colostomy creation were injury location: Rectal versus left colon (odds ratio [OR], 2.2), rectal versus right colon (OR, 7.5), left versus right colon (OR, 3.4), GSW (OR, 2.0), ISS ≥ 16 (OR, 1.7), and DCS (OR, 1.6). CONCLUSION: In this exploratory study of 320 combat-related colostomies, distal colon and rectal injuries continue to be diverted at higher rates independent of other comorbidities. Additional outcomes-directed research is needed to determine whether such operative management is beneficial in all patients.

Use of resuscitative endovascular balloon occlusion of the aorta in a highly lethal model of noncompressible torso hemorrhage.

Noncompressible torso hemorrhage is a leading cause of death in trauma, with many patients dying before definitive hemorrhage control. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an adjunct than can be used to expand the window of salvage in patients with end-stage hemorrhagic shock. The aim of this study was to evaluate the effect of continuous and intermittent REBOA (iREBOA) on mortality using a highly lethal porcine model of noncompressible torso hemorrhage. Male splenectomized pigs (70-90 kg) underwent a laparoscopic liver injury (80% resection of left lobe) followed by a 10-min free-bleed period. Animals were then divided into three groups (n = 8) for a 60-min intervention phase (n = 8): continuous occlusion (cREBOA), iREBOA, or no occlusion (nREBOA). Groups then underwent whole blood resuscitation, damage control surgery, and further critical care. Endpoints were mortality and hemodynamic and circulating measures of shock and resuscitation. Systolic blood pressure (in mmHg) at the end of the free-bleed period for cREBOA, iREBOA, and nREBOA was 31 ± 14, 48 ± 28, and 28 ± 17, respectively (P = 0.125). Following the start of the intervention phase, systolic blood pressure was higher in the iREBOA and cREBOA groups compared with the nREBOA (85 ± 37 and 96 ± 20 vs. 42 ± 4; P < 0.001). Overall mortality for the cREBOA, iREBOA, and nREBOA groups was 25.0%, 37.5%, and 100.0% (P = 0.001). Resuscitative endovascular balloon occlusion of the aorta can temporize exsanguinating hemorrhage and restore life-sustaining perfusion, bridging critical physiology to definitive hemorrhage control. Prospective observational studies of REBOA as a hemorrhage control adjunct should be undertaken in appropriate groups of human trauma patients.

Biochemical markers of acute limb ischemia, rhabdomyolysis, and impact on limb salvage.

Biochemical markers of ischemia reperfusion injury have been of interest to vascular surgeons and researchers for many years. Acute limb ischemia is the quintessential clinical scenario where these markers would seem relevant. The use of biomarkers to preoperatively or perioperatively predict which patients will not tolerate limb-salvage efforts or who will have poor functional outcomes after salvage is of immense interest. Creatinine phosphokinase, myoglobin, lactate, lactate dehydrogenase, potassium, bicarbonate, and neutrophil/leukocyte ratios are a few of the studied biomarkers available. Currently, the most well-studied aspect of ischemia reperfusion injury is rhabdomyolysis leading to acute kidney injury. The last 10 years have seen significant progression and improvement in the treatment of rhabdomyolysis, from minor supportive care to use of continuous renal replacement therapy. Identification of specific biomarkers with predictive outcome characteristics in the setting of ischemia reperfusion injury will help guide therapeutic development and potentially mitigate pathophysiologic changes in acute limb ischemia, including rhabdomyolysis. These may further lead to improvements in short- and long-term surgical outcomes and limb salvage, as well as a better understanding of the timing and selection of intervention.