Early Fasciotomy and Limb Salvage and Complications in Military Lower Extremity Vascular Injury.

BACKGROUND: Military guidelines endorse early fasciotomy after revascularization of lower extremity injuries to prevent compartment syndrome, but the real-world impact is unknown. We assessed the association between fasciotomy and amputation and limb complications among lower extremitys with vascular injury. METHODS: A retrospectively collected lower extremity injury database was queried for limbs undergoing attempted salvage with vascular procedure (2004-2012). Limbs were categorized as having undergone fasciotomy or not. Injury and treatment characteristics were collected, as were intervention timing data when available. The primary outcome measure was amputation. Multivariate models examined the impact of fasciotomy on limb outcomes. RESULTS: Inclusion criteria were met by 515 limbs, 335 (65%) with fasciotomy (median 7.7 h postinjury). Of 212 limbs, 174 (84%) with timing data had fasciotomy within 30 min of initial surgery. Compartment syndrome and suspicion of elevated pressure was documented in 127 limbs (25%; 122 had fasciotomy). Tourniquet and shunt use, fracture, multiple arterial and combined arteriovenous injuries, popliteal involvement, and graft reconstruction were more common in fasciotomy limbs. Isolated venous injury and vascular ligation were more common in nonfasciotomy limbs. Fasciotomy timing was not associated with amputation. Controlling for limb injury severity, fasciotomy was not associated with amputation but was associated with limb infection, motor dysfunction, and contracture. Sixty-three percent of fasciotomies were open for >7 d, and 43% had multiple closure procedures. Fasciotomy revision (17%) was not associated with increased amputation or complications. CONCLUSIONS: Fasciotomy after military lower extremity vascular injury is predominantly performed early, frequently without documented compartment pressure elevation. Early fasciotomy is generally performed in severely injured limbs with a subsequent high rate of limb complications.

Impact of Staged Vascular Management on Limb Outcomes in Wartime Femoropopliteal Arterial Injury.

BACKGROUND: By necessity, wartime arterial injuries undergo staged management. Initial procedures may occur at a forward surgical team (role 2), where temporary shunts can be placed before transfer to a larger field hospital (role 3) for definitive reconstruction. Our objective was to evaluate the impact of staging femoropopliteal injury care on limb outcomes. METHODS: A military vascular injury database was queried for Iraq/Afghanistan casualties with femoropopliteal arterial injuries undergoing attempted reconstruction (2004-2012). Cases were grouped by initial arterial management: shunt placed at role 2 (R2SHUNT), reconstruction at role 2 (R2RECON), and initial management at role 3 (R3MGT). The primary outcome was limb salvage; secondary outcomes were limb-specific complications. Descriptive and intergroup comparative statistics were performed with significance defined at P ≤ 0.05. RESULTS: Of 257 cases, all but 4 had definitive reconstruction before evacuation to Germany (median, 2 days): 46 R2SHUNT, 84 R2RECON, and 127 R3MGT; median Mangled Extremity Severity Score was 6 for all groups. R2SHUNT had median extremity Abbreviated Injury Scale--vascular of 4 (other groups, 3; P < 0.05) and was more likely to have concomitant venous injury and to undergo fasciotomy. Shunts were used for 5 ± 3 hr. About 24% of R2RECON repairs were revised at role 3. Limb salvage rate of 80% was similar between groups, and 62% of amputations performed within 48 hr of injury. Rates of limb and composite graft complications were similar between groups. Thrombosis was more common in R2SHUNT (22%) than R2RECONST (6%) or R3MGT (12%) (P = 0.03). Late (>48 hr) thrombosis rates were similar, whereas 60% of R2SHUNT thromboses occurred on day of injury (P = 0.003 vs. 25% and 0%). CONCLUSIONS: Staged femoropopliteal injury care is associated with similar limb salvage to initial role 3 management. Early thrombosis is likely because of shunt failure but does not lead to limb loss. Current military practice guidelines are appropriate and may inform civilian vascular injury management protocols.

Venovenous bypass using continuous renal replacement therapy and endovascular inferior vena cava reconstruction to treat bilateral massive iliocaval deep venous thrombosis.

Many inferior vena cava (IVC) anomalies remain asymptomatic because of collateral circulation, but thrombosis of these channels can cause acute deep venous thrombosis with serious sequelae. For those with threatened limbs, anticoagulation is the mainstay of treatment, with endovascular pharmacomechanical thrombolysis replacing open surgical thrombectomy. Described is a severe case of massive iliocaval deep venous thrombosis with bilateral lower extremity Rutherford IIb acute limb ischemia in a patient with congenital IVC atresia. After initial thrombolysis, endovascular IVC reconstruction was accomplished to decompress the lower extremities. The patient ultimately required a right through-knee amputation but remains ambulatory with a prosthetic.

Initial Inoculation Concentration Does Not Affect Final Bacterial Colonization of In vitro Vascular Conduits.

BACKGROUND: Despite improved peri-operative care, prosthetic graft infections continue to cause substantial morbidity and mortality. Contemporary graft infection models have tested a conduit's infectability using varying concentrations without standardization. Using a static assay in vitro model, we sought to evaluate the impact of inoculation concentration on vascular conduit attachment. METHODS: The 2-hour and 24-hour attachment of Staphylococcus aureus TCH1516 and Pseudomonas aeruginosa PA01-UW were determined on polytetrafluoroethylene (PTFE), Dacron®, nitinol, cobalt chromium, and Viabahn® (W.L. Gore and Associates, Newark, DE) endoprotheses. Individually and in combination, concentrations at 104, 105, 106, 107, and 108 were tested on 2-mm sections of each graft. After each time interval, the prosthetics were rinsed to remove non-attached bacteria, sonicated to release the attached bacteria, spiral plated, and then analyzed for the attached concentration. RESULTS: After two hours, the higher initial inoculation concentration translated into a higher attachment percentage, but the mean attachment percentage was only 14.8% in the 108 group. Pseudomonas aeruginosa had the greatest mean attachment across all material and concentration groups. The sequence of attachment on the conduits followed a constant order: Dacron, PTFE, cobalt, nitinol, and Viabahn with no difference between Dacron and PTFE. Although there were still differences at the 24-hour mark, the median attachment at each concentration was greater than the highest initial concentration (108). CONCLUSIONS: Initial attachment percentage is poor consistently regardless of inoculation concentration, however, Staphylococcus aureus and Pseudomonas aeruginosa are still able to achieve full attachment after 24 hours. A concentration of less than 107 should be used in vascular graft infection models to ensure adequate bacterial attachment.

Successful Use of Nellix and Endovascular Aortic Sealing Technology for Treatment of Aortic Rupture in a Porcine Model.

BACKGROUND: Endovascular aortic sealing (EVAS) represents a recent transformation in approach for treatment of aortic aneurysms. Initial reporting has shown that EVAS using the Nellix device is safe with similar complication rates to standard endovascular aortic repair (EVAR). What remains unknown is how EVAS technology will behave in the ruptured setting. The purpose of this report is to discuss how EVAS system and endobag technology behave when deployed in a porcine model of aortic rupture. METHODS: A controlled left retroperitoneal rupture was created in 20 large swine. Following rupture, an EVAS system was deployed across the rupture site to seal the area. The primary end point was seal from ongoing hemorrhage. Other parameters were examined to include endobag extravasation, aortic wall pressure measurements and device behavior in a live tissue model. RESULTS: Of the EVAS systems used, 15 Nellix (Endologix, Irvine, CA) devices and 5 novel EVAS systems were used. Of the correctly deployed devices, 100% sealed the rupture (n = 19). One device was deployed above the rupture site, and seal was not achieved secondary to malpositioning. Endobag extravasation was seen with an average protrusion of 7.7 mm. No other areas of aortic injury were noted secondary to endobag trauma. Pressure recording from behind the endobag indicates loss of pulsatile flow to the aortic wall with polymer curing. CONCLUSIONS: Endovascular aortic sealing for rupture is feasible and performs well in a porcine model of aortic rupture. Polymer extravasation is seen and may be controllable by the implanter. Once the polymer has cured, pulsatile aortic wall pressure is no longer present. EVAS represents an emerging technology for treatment of aortic rupture.

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.

Evaluation of the learning curve for fenestrated endovascular aneurysm repair.

OBJECTIVE: The objective of this study was to evaluate the learning curve for fenestrated endovascular aortic aneurysm repair (FEVAR). METHODS: Data were collected prospectively on all FEVAR procedures conducted by a single surgeon between June 2007 and January 2015. During the study period, 136 FEVARs were performed, and this experience was divided into four quartiles each consisting of 34 cases. Clinical outcomes evaluated included perioperative death and major complications. Process outcomes included length of procedure, fluoroscopy time, contrast material use, estimated blood loss, and intensive care unit length of stay. RESULTS: During the study period, there was a statistically significant increase in the complexity of cases as evidenced by an increase in the proportion of cases with two or more fenestrations from 52.9% in the first quartile to 88.2% in the fourth quartile (P = .001). Despite this, there was a steady decrease in the proportion of patients suffering perioperative death or major complications from 23.5% in the first quartile to 8.8% in the fourth quartile. After adjustment for potential confounding factors, the odds of death or major complication were cut by 52.4% per quartile increase (95% confidence interval [CI], 7.8%-75.5%; P = .028). In addition, among cases with two or more fenestrations, geometric mean length of procedure was reduced from 223.8 minutes in the first quartile to 149.6 minutes in the fourth quartile, and geometric mean fluoroscopy time was reduced from 58.6 minutes in the first quartile to 31.5 minutes in the fourth quartile. After adjustment, there was an estimated 9.9% reduction in geometric mean procedure length per quartile increase (95% CI, 3.5%-15.9%; P = .003) and a 17.6% reduction in geometric mean fluoroscopy time per quartile increase (95% CI, 10.9%-23.8%; P < .0001). CONCLUSIONS: Despite an increase in case complexity, there was evidence for significant improvement in important clinical and process outcomes during the study period. We believe that much of this improvement was attributable to several key advances in the FEVAR procedure that were instituted during the study period and are discussed herein.

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.

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).

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.

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.

Endovascular aortoiliac reconstruction to allow excision of an infected axillobifemoral bypass.

Axillofemoral graft reconstructions were initially intended to restore lower extremity perfusion in high-risk patients with symptomatic aortoiliac atherosclerotic occlusive disease. However, these reconstructions are now relegated to "bailout" procedures for infected grafts or high-risk critical limb ischemia patients that fail endovascular therapy. Infection of an extra-anatomic bypass graft is a challenging complication as it occurs in poor operative candidates with limited revascularization options and failure has a high rate of amputation and mortality. Described is a novel approach using endovascular reconstruction to treat symptomatic Trans-Atlantic Inter-Society Consensus-II type D aortoiliac lesions allowing for complete excision of an infected axillobifemoral bypass.

Combined arteriovenous thrombolytic infusion for refractory renal vein thrombosis.

Acute renal vein thrombosis can rapidly lead to significant impairment and eventual loss of renal function. Classically presenting with flank pain, hematuria, and laboratory markers consistent with acute kidney injury, therapeutic anticoagulation is the mainstay of treatment. However, endovascular surgery offers a safe and effective alternative for renal salvage in the setting of acute renal vein thrombosis. Described is the use of combined arteriovenous thrombolytic infusion for refractory renal vein thromboses to quickly and effectively decrease clot burden in the micro- and macrovenous circulations while limiting systemic exposure.