Acute Aortic Syndromes from Diagnosis to Treatment-A Comprehensive Review.

This work aims to provide a comprehensive description of the characteristics of a group of acute aortic diseases that are all potentially life-threatening and are collectively referred to as acute aortic syndromes (AASs). There have been recent developments in the care and diagnostic plan for AAS. A substantial clinical index of suspicion is required to identify AASs before irreversible fatal consequences arise because of their indefinite symptoms and physical indicators. A methodical approach to the diagnosis of AAS is addressed. Timely and suitable therapy should be started immediately after diagnosis. Improving clinical outcomes requires centralising patients with AAS in high-volume centres with high-volume surgeons. Consequently, the management of these patients benefits from the increased use of aortic centres, multidisciplinary teams and an "aorta code". Each acute aortic entity requires a different patient treatment strategy; these are outlined below. Finally, numerous preventive strategies for AAS are discussed. The keys to good results are early diagnosis, understanding the natural history of these disorders and, where necessary, prompt surgical intervention. It is important to keep in mind that chest pain does not necessarily correspond with coronary heart disease and to be alert to the possible existence of aortic diseases because once antiplatelet drugs are administered, a blocked coagulation system can complicate aortic surgery and affect prognosis. The management of AAS in "aortic centres" improves long-term outcomes and decreases mortality rates.

Outcomes Associated With Aortic Balloon Occlusion Time in Patients With Zone 1 Resuscitative Endovascular Balloon Occlusion of the Aorta.

INTRODUCTION: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has the potential to cause clinically relevant systemic ischemic burden with long durations of aortic occlusion (AO). We aimed to examine the association between balloon occlusion time and clinical complications and mortality outcomes in patients undergoing zone 1 REBOA. METHODS: A retrospective cohort analysis of American Association for the Surgery of Trauma Aortic Occlusion for Resuscitation in Trauma and Acuteregistry patients with Zone 1 REBOA between 2013 and 2022 was performed. Patients with cardiopulmonary resuscitation on arrival or who did not survive past the emergency department were excluded. Total AO times were categorized as follows: <15 min, 15-30 min, 31-60 min, and >60 min. Clinical and procedural variables and in-hospital outcomes were compared across groups using bivariate and multivariate regression analyses. RESULTS: There were 327 cases meeting inclusion criteria (n = 51 < 15 min, 83 15-30 min, 98 31-60 min, and 95 > 60 min, respectively). AO >60 min had higher admission lactate (8 ± 6; P = 0.004) compared to all other time groups, but injury severity score, heart rate, and systolic blood pressure were similar. Group average times from admission to definitive hemorrhage control ranged from 82 to 103 min and were similar across groups (85 min in AO >60 group). Longer AO times were associated with greater red blood cell, fresh frozen plasma transfusions (P < 0.001), and vasopressor use (P = 0.001). Mortality was greatest in the >60 min group (73%) versus the <15 min, 15-30 min, and 31-60 min groups (53%, 43%, and 45%, P < 0.001). With adjustment for injury severity score, systolic blood pressure, and lactate, AO >60 min had greater mortality (OR 3.7, 95% CI 1.6-9.4; P < 0.001) than other AO duration groups. Among 153 survivors, AO >60 min had a higher rate of multiple organ failure (15.4%) compared to the other AO durations (0%, 0%, and 4%, P = 0.02). There were no differences in amputation rates (0.7%) or spinal cord ischemia (1.4%). acute kidney injury was seen in 41% of >60 min versus 21%, 27%, and 33%, P = 0.42. CONCLUSIONS: Though greater preocclusion physiologic injury may have been present, REBOA-induced ischemic insult was correlated with poor patient outcomes, specifically, REBOA inflation time >60 min had higher rates of mortality and multiple organ failure. Minimizing AO duration should be prioritized, and AO should not delay achieving definitive hemostasis. Partial REBOA may be a solution to extend safe AO time and deserves further study.

Vascular Reconstruction and Limb Loss in Military Tibial Artery Injuries.

BACKGROUND: Selective operative management of injuries to the tibial arteries is controversial, with the necessity of revascularization in the face of multiple tibial arteries debated. Tibial artery injuries are frequently encountered in military trauma, but revascularization practices and outcomes are poorly defined. We aimed to investigate associations between the number of injured vessels and reconstruction and limb loss rates in military casualties with tibial arterial trauma. METHODS: A US military database of lower extremity vascular injuries from Iraq and Afghanistan (2004-2012) was queried for limbs sustaining at least 1 tibial artery injury. Injury, intervention characteristics, and limb outcomes were analyzed by the number of tibial arteries injured (1, T1; 2, T2; 3, T3). RESULTS: Two hundred twenty one limbs were included (194 T1, 22 T2, 5 T3). The proportions with concomitant venous, orthopedic, nerve, or proximal arterial injuries were similar between groups. Arterial reconstruction (versus ligation) was performed in 29% of T1, 63% of T2, and universally in T3 limbs (P < 0.001). Arterial reconstruction was via vein graft (versus localized repair) in 62% of T1, 54% of T2, and 80% of T3 (P = 0.59). T3 received greater blood transfusion volume (P = 0.02), and fasciotomy was used universally (versus 34% T1 and 14% T2, P = 0.05). Amputation rates were 23% for T1, 26% for T2, and 60% for T3 (P = 0.16), and amputation was not significantly predicted by arterial ligation in T1 (P = 0.08) or T2 (P = 0.34) limbs. Limb infection was more common in T3 (80%) than in T1 (25%) or T2 (32%, P = 0.02), but other limb complication rates were similar. CONCLUSIONS: In this series of military lower extremity injuries, an increasing number of tibial arteries injured was associated with the increasing use of arterial reconstruction. Limbs with all 3 tibial arteries injured had high rates of complex vascular reconstruction and eventual amputation. Limb loss was not predicted by arterial ligation in 1-vessel and 2-vessel injuries, suggesting that selective reconstruction in these cases is advisable.

Association between time to revascularization and limb loss in military femoropopliteal arterial injuries.

OBJECTIVE: Expeditious revascularization is key to limb salvage after arterial injuries, but the relationship between time to revascularization and amputation risk is not well-defined. We aimed to explore amputation risk based on time to revascularization in a cohort of military femoropopliteal arterial injuries. METHODS: A database of vascular injuries from Iraq and Afghanistan casualties (2004-2012) was queried for femoral (common, superficial, or deep) and/or popliteal arterial injuries that underwent revascularization. Time from injury to initial revascularization (via shunt or reconstruction) was divided into groups of <3 hours, 3 to 6 hours, 6 to 9 hours, and >9 hours, and bivariate comparisons were performed. RESULTS: Revascularization times were available for 120 cases. Injury and treatment characteristics by time group were generally similar between time groups. Shunting and vein injuries were more common in limbs revascularized earlier, whereas blast mechanism and fasciotomy were more common with later revascularization. Ten cases (8%) underwent revascularization in less than 3 hours, 63 (53%) were revascularized in 3 to 6 hours, 33 (28%) in 6 to 9 hours, and 14 (12%) after 9 hours. Amputation rates within the cohorts were 10%, 21%, 24%, and 50%, respectively (P = .085, χ2 of amputation rates across time groups). The mean ± standard deviation revascularization time for amputated limbs was 442 ± 348 minutes vs 347 ± 183 minutes for salvaged limbs (P = .057). Amputation was performed in 19% of limbs revascularized in <6 hours and in 32% revascularized >6 hours from injury (P = .112). The >9-hour group, however, had a 50% amputation rate vs 21% for those with revascularization in <9 hours (P = .016). Fractures were more common in >9-hour limbs than <9-hour limbs (79% vs 44%; P = .016), but other limb injury characteristics were similar, with no difference in limb injury severity scores. Among 91 salvaged limbs, neither vascular nor other complications were predicted by time to revascularization. All seven >9-hour limbs had a limb complication, most commonly infection (71%), and three (42%) required a skin graft to close their fasciotomies. CONCLUSIONS: Increasing time from injury to initial revascularization was associated with increasing rates of limb loss. Revascularization within 3 hours of injury resulted in a low amputation rate, whereas one-half of limbs treated after 9 hours were amputated. Arterial shunting was associated with earlier revascularization and should be considered a mainstay of combat casualty vascular care. Forward-deployed surgical assets play a pivotal role in providing early revascularization and reducing rates of limb loss in modern combat casualty care.

Recent advances and the future of abdominopelvic and lower extremity vascular injury management.

Despite advances in open and endovascular management of trauma, vascular injuries remain a source of devastating outcomes. This narrative review of the literature between 2018 and 2023 explored recent advances in abdominopelvic and lower extremity vascular injury management. New conduit choices, use of temporary intravascular shunts, and advances in endovascular management of vascular trauma were reviewed. Although endovascular techniques are being applied more frequently, there is a paucity of reporting on long-term outcomes. Open surgery is durable and effective and remains the gold standard for repairing most abdominal, pelvic, and lower extremity vascular injuries. Vascular reconstruction conduit options are currently limited to the autologous vein, prosthetic grafts, and cryopreserved cadaveric xenografts; each type has its own application challenges. The temporary intravascular shunts can be used to restore early perfusion to ischemic limbs and increase the chances of limb salvage, or when transfer of care is needed. Resuscitative balloon occlusion of the inferior vena cava has been a research-heavy topic to investigate the possible implications in patients with trauma. Early diagnosis, appropriate use of technology, and time-sensitive management can make all the difference in the lives of patients with vascular trauma. Endovascular management of vascular trauma is evolving and gaining wider acceptance for treatment of vascular injuries. Computed tomography angiography is widely available and is the current gold standard for diagnosis. Autologous vein remains the gold standard for conduit with the future promise of new innovative conduits. Vascular surgeons have an important role in vascular trauma management.

Arterial Access Complications Following Percutaneous Femoral Access in 24-Hour Resuscitative Endovascular Balloon Occlusion of the Aorta Survivors.

INTRODUCTION: With the use of resuscitative endovascular balloon occlusion of the aorta (REBOA) comes the potential for vascular access site complications (VASCs) and limb ischemic sequelae. We aimed to determine the prevalence of VASC and associated clinical and technical factors. METHODS: A retrospective cohort analysis of 24-h survivors undergoing percutaneous REBOA via the femoral artery in the American Association for the Surgery of Trauma Aortic Occlusion for Resuscitation in Trauma and Acute care surgery registry between Oct 2013 and Sep 2021 was performed. The primary outcome was VASC, defined as at least one of the following: hematoma, pseudoaneurysm, arteriovenous fistula, arterial stenosis, or the use of patch angioplasty for arterial closure. Associated clinical and procedural variables were examined. Data were analyzed using Fisher exact test, Mann-Whitney-U tests, and linear regression. RESULTS: There were 34 (7%) cases with VASC among 485 meeting inclusion criteria. Hematoma (40%) was the most common, followed by pseudoaneurysm (26%) and patch angioplasty (21%). No differences in demographics or injury/shock severity were noted between cases with and without VASC. The use of ultrasound (US) was protective (VASC, 35% versus no VASC, 51%; P = 0.05). The VASC rate in US cases was 12/242 (5%) versus 22/240 (9.2%) without US. Arterial sheath size >7 Fr was not associated with VASC. US use increased over time (R2 = 0.94, P < 0.001) with a stable rate of VASC (R2 = 0.78, P = 0.61). VASC were associated with limb ischemia (VASC, 15% versus no VASC, 4%; P = 0.006) and arterial bypass procedures (VASC 3% versus no VASC 0%; P < 0.001) but amputation was uncommon (VASC, 3% versus no VASC, 0.4%; P = 0.07). CONCLUSIONS: Percutaneous femoral REBOA had a 7% VASC rate which was stable over time. VASC are associated with limb ischemia but need for surgical intervention and/or amputation is rare. The use of US-guided access appears to be protective against VASC and is recommended for use in all percutaneous femoral REBOA procedures.

The Characteristics and Results of Endovascular Devices in Trauma (CREDiT) study: Multi-institutional results.

INTRODUCTION: Endovascular techniques are increasingly used to repair major traumatic vascular injuries, but most endovascular implants are not designed/approved for trauma-specific indications. No inventory guidelines exist for the devices used in these procedures. We aimed to describe the use and characteristics of endovascular implants used for repair of vascular injuries to allow for better inventory management. METHODS: This CREDiT study is a six-year retrospective cohort analysis of endovascular procedures performed for repair of traumatic arterial injuries at five participating US trauma centers. For each treated vessel, procedural and device details were recorded and outcomes assessed with the aim of defining the range of implants and sizes used for these interventions. RESULTS: A total of 94 cases were identified; 58 (61%) were descending thoracic aorta, 14 (15%) axillosubclavian, 5 carotid, 4 abdominal aortic, 4 common iliac, 7 femoropopliteal, and 1 renal. Vascular surgeons performed 54% of cases, trauma surgeons 17%, IR/CT Surgery 29%. Systemic heparin was administered in 68% and procedures were performed a median of 9 h after arrival (IQR 3-24 h). Primary arterial access was femoral in 93% of cases, 49% were bilateral. Brachial/radial access was used primarily in 6 cases, and secondary to femoral in 9. The most common implant was self-expanding stent graft; 18% used >1 stent. Implants ranged in diameter and length based on vessel size. Five of 94 implants underwent reintervention (1 open surgery) at a median of 4d postop (range 2-60d). Two occlusions and 1 stenosis were present at follow-up at a median of 1 month (range 0-72 m). CONCLUSIONS: Endovascular reconstruction of injured arteries requires a broad range of implant types, diameters, and lengths which should be readily available in trauma centers. Stent occlusions/stenoses are rare and can typically be managed by endovascular means.

Analysis of 5-year Mortality following Lower Extremity Amputation due to Vascular Disease.

Mortality rates following major lower extremity amputations (LEAs) 30 days-365 days postoperative have decreased, but 5-year rates remain high at 40.4%-70%. These data may not reflect recent advances in peripheral arterial disease (PAD) care, and comorbidities of chronic PAD may lead to mortality more frequently than the amputation itself. Mortality rates between diabetic and nondiabetic patients were also analyzed. Methods: The California Office of Statewide Health Planning and Development hospital database was queried for patients admitted January 1, 2007-December 31, 2018. ICD-9-CM codes identified patients with vascular disease and an amputation procedure. Results: There were 26,669 patients. The 30-day, 90-day, 1-year, and 5-year major LEA mortality rates were 4.82%, 8.62%, 12.47%, and 18.11%, respectively. Weighted averages of 30-day, 90-day, 1-year, and 5-year major LEA mortality rates in the literature are 13%, 15.40%, 47.93%, and 60.60%, respectively. Mortality risk associated with vascular disease after amputation (hazard ratio = 22.07) was 11 times greater than risk associated with amputation-specific complications from impaired mobility (hazard ratio = 1.90; P < 0.01). Having diabetes was associated with lower mortality at 30 days, 90 days, and 1 year (P < 0.01) but not at 5 years (P = 0.22). Conclusions: This study suggests that people may be living longer after their major LEA than was previously thought. This study suggests that patients' PAD may play a bigger role in contributing to their mortality than complications from loss of mobility postamputation. Although having diabetes was associated with lower postamputation mortality, the difference was no longer significant by 5 years.

Analysis of Concomitant and Isolated Venous Injury in Military Lower Extremity Trauma.

BACKGROUND: The implications of major venous injury to the lower extremity are not well established. We aimed to determine the significance of concomitant and isolated femoropopliteal venous injury and assess the impact of surgical management strategies on limb outcomes. METHODS: The Fasciotomy and Vascular Injury Outcomes database was queried for limbs sustaining femoropopliteal arterial, venous, or concomitant injuries in Iraq or Afghanistan between 2004 and 2012. Demographics, injury patterns and severity, interventions, and outcomes were compared between patients sustaining isolated arterial injuries (IAIs) and concomitant arteriovenous injuries (AVIs). In limbs with any venous injury, outcomes were compared between those undergoing venous repair and venous ligation. RESULTS: Three hundred thirty patients (133 IAIs, 135 AVIs, 62 isolated venous injuries [IVIs]) were included. AVI was associated with greater limb injury severity: median extremity Abbreviated Injury Scale (AVI 4 vs. IAI 3, P = 0.01), Mangled Extremity Severity Score >7 (25.9% vs. 13.5%, P = 0.01), and multilevel vascular injury (6.7% vs. 0.8%, P = 0.01) and with greater fasciotomy use (83.0% vs. 69.2%, P = 0.01). No differences were present in tourniquet use/time, shunting, or nature of arterial repair. No differences in vascular or limb complications (71.1% vs. 63.9%, P = 0.21) or amputation rate (25.9% vs. 18.8%, P = 0.16) were present, though the limb deep venous thrombosis rate was 12.6% in AVIs versus 7.5% in IAIs (P = 0.17). Limbs with IVI had a 12.9% amputation and a 74.2% complication rate. Repair (n = 103) versus ligation (n = 94) of venous injuries was not associated with a difference in amputation (18.4% vs. 25.5%, P = 0.23) or limb complication rates (71.8% vs. 72.3%, P = 0.94). CONCLUSIONS: Despite higher extremity injury severity and more frequent fasciotomies, concomitant venous injury was not associated with poorer limb salvage or complications. With nontrivial amputation and complication rates, IVI is indicative of severe limb trauma. Repair of femoropopliteal venous injuries does not appear to influence limb outcomes.

Perspectives on competencies for care in austere settings.

ABSTRACT: Austerity in surgical care may manifest by limited equipment/supplies, deficient infrastructure (power, water), rationing/triage requirements, or the unavailability of specialty surgical or medical expertise. Some settings in which surgeons may experience austerity include the following: military deployed operations (domestic and foreign), humanitarian surgical missions, care in rural or remote settings, mass-casualty events, natural disasters, and/or care in low- and some middle-income countries. Expanded competencies beyond those required in routine surgical practice can optimize the quality of surgical care in such settings. The purpose of this expert panel review is to introduce those competencies.

Survival benefit for pelvic trauma patients undergoing Resuscitative Endovascular Balloon Occlusion of the Aorta: Results of the AAST Aortic Occlusion for Resuscitation in Trauma Acute Care Surgery (AORTA) Registry.

BACKGROUND: Aortic occlusion (AO) to facilitate the acute resuscitation of trauma and acute care surgery patients in shock remains a controversial topic. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is an increasingly deployed method of AO. We hypothesized that in patients with non-compressible hemorrhage below the aortic bifurcation, the use of REBOA instead of open AO may be associated with a survival benefit. METHODS: From the AAST Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery (AORTA) registry, we identified 1494 patients requiring AO from 45 Level I and 4 Level II trauma centers. Presentation, intervention, and outcome variables were analyzed to compare REBOA vs open AO in patients with non-compressible hemorrhage below the aortic bifurcation. RESULTS: From December 2014 to January 2019, 217 patients with Zone 3 REBOA or Open AO who required pelvic packing, pelvic fixation or pelvic angio-embolization were identified. Of these, 109 AO patients had injuries isolated to below the aortic bifurcation (REBOA, 84; open AO, 25). Patients with intra-abdominal or thoracic sources of bleeding, above deployment Zone 3 were excluded. Overall mortality was lower in the REBOA group (35.% vs 80%, p <.001). Excluding patients who arrived with CPR in progress, the REBOA group had lower mortality (33.33% vs. 68.75%, p = 0.012). Of the survivors, systemic complications were not significantly different between groups. In the REBOA group, 16 patients had complications secondary to vascular access. Intensive care lengths of stay and ventilator days were both significantly shorter in REBOA patients who survived to discharge. CONCLUSIONS: This study compared outcomes for patients with hemorrhage below the aortic bifurcation treated with REBOA to those treated with open AO. Survival was significantly higher in REBOA patients compared to open AO patients, while complications in survivors were not different. Given the higher survival in REBOA patients, we conclude that REBOA should be used for patients with hemorrhagic shock secondary to pelvic trauma instead of open AO. LEVEL III EVIDENCE: Therapeutic.

Managing Vascular Trauma: Trauma Surgeons versus Vascular Surgeons.

OBJECTIVES: Changes in vascular trauma care and trainee exposure to vascular surgery have raised questions regarding who should take care of vascular trauma patients. This study aimed to determine nationwide trends and perceptions regarding the management of vascular trauma amongst vascular and trauma surgeons. MATERIAL AND METHODS: Online surveys were administered to trauma surgeons through the American Association for the Surgery of Trauma (AAST) and to vascular surgeons through the Vascular and Endovascular Surgery Society (VESS) and Western Vascular Society (WVS) in February 2021. Demographics, practice-related information, and interest in, experience and comfort level with vascular trauma were queried. Trainees and those practicing outside the United States were excluded. Results were analyzed using Stata/BE v16.1. RESULTS: 247 surgeons were included in the final study population, of which 163 (66%) were trauma surgeons (T) and 84 (34%) were vascular surgeons (V). Vascular surgeons were younger (46 v 51y, P < .001) and had fewer years in practice (10 v 17y, P < .001). Vascular surgeons had greater experience and comfort with managing vascular trauma, but less interest in both vascular and endovascular trauma care when compared to trauma surgeons. Inability to maintain skillset (27%) and unfamiliarity with techniques (32%) were the most common barriers to practicing vascular trauma cited by trauma surgeons. DISCUSSION: Despite significant interest in practicing vascular trauma amongst trauma surgeons compared to vascular surgeons, most feel unprepared to do so. Collaboration between vascular and trauma surgeons could close the experience gap and appeal to the interests of both groups.

Systematic review of temporary intravascular shunt use in military and civilian extremity trauma.

BACKGROUND: The use of temporary intravascular shunts (TIVS) in the setting of military and civilian trauma has grown in recent years, predominantly because of the mounting evidence of improved limb outcomes. We sought to characterize the use and outcomes of TIVS in trauma through a systematic review of military and civilian literature. METHODS: The MEDLINE, EBSCO, EMBASE, and Cochrane databases were searched for studies on TIVS use in military and civilian trauma settings published between January 2000 and March 2021. Reports lacking systematic data collection along with those with insufficient TIVS descriptive and outcome data were excluded. Data regarding the characteristics and outcomes of TIVS were assessed and collective syntheses of military and civilian data performed. RESULTS: Twenty-one reports were included, 14 from civilian trauma centers or databases and 7 from military field data or databases (total of 1,380 shunts in 1,280 patients). Sixteen were retrospective cohort studies, and four were prospective. Five studies had an unshunted comparison group. Shunts were predominantly used in the lower extremity and most commonly for damage control indications. Dwell times were infrequently reported and were not consistently linked to shunt thrombosis or other complications. Anticoagulation during shunting was sparsely reported and inconsistently applied. Shunted limbs had higher injury severity than unshunted limbs but similar salvage rates. CONCLUSION: Temporary intravascular shunts are effective for expeditious restoration of perfusion in severely injured limbs and likely contribute to limb salvage. There is a paucity of comparative TIVS data in the literature and no consistently applied reporting standards, so controversies regarding TIVS use remain. LEVEL OF EVIDENCE: Systematic Review, level IV.

Life over limb: Arterial access-related limb ischemic complications in 48-hour REBOA survivors.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is increasingly used in some trauma settings. Arterial access-related limb ischemic complications (ARLICs) resulting from the femoral arterial access required for REBOA are largely under reported. We sought to describe the incidence of these complications and the clinical, technical, and device factors associated with their development. METHODS: This was a retrospective cohort study of records of adult trauma patients from the American Association for the Surgery of Trauma Aortic Occlusion for Resuscitation in Trauma and Acute care surgery registry between October 2013 and September 2020 who had REBOA and survived at least 48 hours. The primary outcome was ARLIC, defined as clinically relevant extremity ischemia or distal embolization. Relevant factors associated with ARLIC were also analyzed. RESULTS: Of 418 identified patients, 36 (8.6%) sustained at least one ARLIC; 22 with extremity ischemia, 25 with distal embolism, 11 with both. Patient demographics and injury characteristics were similar between ARLIC and no ARLIC groups. Access-related limb ischemic complication was associated with larger profile devices (p = 0.009), cutdown access technique (p = 0.02), and the presence of a pelvic external fixator/binder (p = 0.01). Patients with ARLIC had higher base deficit (p = 0.03) and lactate (p = 0.006). One hundred fifty-six patients received tranexamic acid (TXA), with 22 (14%) ARLICs. The rate of TXA use among ARLIC patients was 61% (vs. 35% TXA for non-ARLIC patients, p = 0.002). Access-related limb ischemic complication did not result in additional in-hospital mortality, however, ARLIC had prolonged hospital LOS (31 vs. 24 days, p = 0.02). Five ARLIC required surgical intervention, three patch angioplasty (and two with associated bypass), and four ARLIC limbs were amputated. CONCLUSION: Femoral artery REBOA access carries a risk of ARLIC, which is associated with unstable pelvis fractures, severe shock, and strongly with the administration of TXA. Use of lower-profile devices and close surveillance for these complications is warranted in these settings and caution should be exercised when using TXA in conjunction with REBOA. LEVEL OF EVIDENCE: Prognostic and Epidemiologic, Level III.

Evaluation of a novel hydrogel intravascular embolization agent in a swine model of fatal uncontrolled solid organ hemorrhage and coagulopathy.

INTRODUCTION: Current agents for the intravascular embolization of traumatic hemorrhage are used off-label and have been minimally studied with respect to their performance under differing coagulation conditions. We studied the hemorrhage control efficacy of a novel, liquid, polyethylene glycol-based hydrogel delivered as two liquid precursors that polymerize within the target vessel in a unique animal model of severe solid organ injury with and without dilutional coagulopathy. METHODS: Anesthetized swine (n = 36, 45 ± 3 kg) had laparotomy and splenic externalization. Half underwent 50% isovolemic hemodilution with 6% hetastarch and cooling to 33°C-35°C (coagulopathic group). All animals had controlled 20 mL/kg hemorrhage and endovascular proximal splenic artery access with a 4F catheter via a right femoral sheath. Splenic transection and 5-minute free bleeding were followed by treatment (n = 5/group) with 5 mL of gelfoam slurry, three 6-mm coils, up to 6 mL of hydrogel, or no treatment (n = 3, control). Animals received 15 mL/kg plasma and were monitored for 6 hours with continuous blood loss measurement. RESULTS: Coagulopathy was successfully established, with coagulopathic animals having greater pretreatment blood loss and earlier mean time to death regardless of the treatment group. All control animals died within 100 minutes. Overall survival without coagulopathy was 5/5 for hydrogel, 4/5 for coil, and 3/5 for gelfoam. With coagulopathy, one hydrogel animal survived to the end of the experiment, with 2/4 hydrogel deaths occurring in the final hour of observation. In noncoagulopathic animals, hydrogel demonstrated improved survival time (P < .01) and post-treatment blood loss (1.46 ± 0.8 mL/kg) over controls (18.8 ± 0.7, P = .001), gelfoam (4.7 ± 1.3, P > .05), and coils (4.6 ± 1.5, P > .05). In coagulopathic animals, hydrogel had improved survival time (P = .003) and decreased blood loss (4.2 ± 0.8 mL/kg) compared with control (20.4 ± 4.2, P = .003). CONCLUSIONS: The hydrogel demonstrated equivalent hemorrhage control performance to standard treatments under noncoagulopathic conditions and improved performance in the face of dilutional coagulopathy. This agent should be explored as a potential preferable treatment for the embolization of traumatic solid organ and other injuries. (JVS-Vascular Science 2021;2:43-51.). CLINICAL RELEVANCE: In a translational model of severe solid organ injury hemorrhage with and without coagulopathy, a novel hydrogel transarterial embolization agent demonstrated equivalent hemorrhage control performance to standard agents under noncoagulopathic conditions and improved performance in the face of dilutional coagulopathy. This agent represents a promising future treatment for the embolization of traumatic solid organ and other injuries.

Performance of a novel temporary arterial shunt in a military-relevant controlled hemorrhage swine model.

BACKGROUND: In military trauma, temporary vascular shunts restore arterial continuity until delayed vascular reconstruction, often for a period of hours. A novel US Air Force-developed trauma-specific vascular injury shunt (TS-VIS) incorporates an accessible side port for intervention or monitoring, which may improve patency under adverse hemodynamic conditions. Our objective was to evaluate TS-VIS patency in the setting of volume-limited resuscitation from hemorrhagic shock. METHODS: Female swine (70-90 kg) underwent 30% hemorrhage and occlusion of the left external iliac artery for 30 minutes. Animals were allocated to one of three groups (n = 5 per group) by left external iliac artery treatment: Sundt shunt (SUNDT), TS-VIS with arterial pressure monitoring (TS-VIS), or TS-VIS with heparin infusion (10 µ/kg per hour, TS-VISHep). Animals were resuscitated with up to 3 U of whole blood to maintain a mean arterial pressure (MAP) of >60 mm Hg and were monitored for 6 hours. Bilateral femoral arterial flow was continuously monitored with transonic flow probes, and shunt thrombosis was defined as the absence of flow for greater than 5 minutes. RESULTS: No intergroup differences in MAP or flow were observed at baseline or following hemorrhage. Animals were hypotensive at shunt placement (MAP, 35.5 ± 7.3 mm Hg); resuscitation raised MAP to >60 mm Hg by 26.5 ± 15.5 minutes. Shunt placement required 4.5 ± 1.8 minutes with no difference between groups. Four SUNDT thrombosed (three before 60 minutes). One SUNDT thrombosed at 240 minutes, and two TS-VIS and one TS-VISHep thrombosed between 230 and 282 minutes. Median patency was 21 minutes for SUNDT and 360 minutes for both TS-VIS groups (p = 0.04). While patent, all shunts maintained flow between 60% and 90% of contralateral. CONCLUSION: The TS-VIS demonstrated sustained patency superior to the Sundt under adverse hemodynamic conditions. No benefit was observed by the addition of localized heparin therapy over arterial pressure monitoring by the TS-VIS side port.

Outcomes of Arterial Grafts for the Reconstruction of Military Lower Extremity Arterial Injuries.

INTRODUCTION: Lower extremity (LE) arterial injuries are common in military casualties and limb salvage is a primary goal. Bypass grafts are the most common reconstructions; however, their specific outcomes are largely unreported. We sought to describe the outcomes of LE arterial grafts among combat casualties and their association with limb loss. METHODS: Retrospective cohort study of 2004-2012 Iraq/Afghanistan casualties with LE arterial injury undergoing bypass graft from a database containing follow-up until amputation, death, or military discharge. Primary outcome was composite graft complications (GC-thrombosis, stenosis, pseudoaneurysm, blowout, and/or arteriovenous fistula). RESULTS: Two hundred and twenty-two grafts were included (99 femoral, 73 popliteal, 48 tibial). 56 (26%) had at least one GC; thrombosis was most common in femoral, stenosis most common in popliteal and tibial. GC was not associated with graft level but was associated with synthetic conduit (P = 0.01) and trended towards an association with multiple-level arterial injuries (P = 0.07). Four of eight (50%) synthetic grafts had amputations, all within 72h. Two of the eight synthetic grafts thrombosed, and both limbs were amputated. There were 52 total amputations. Amputation was performed in 13 (23%) of limbs with a GC and 24% of those without (P = 0.93) Overall, 24 (11%) of grafts thrombosed, 16 within 48h and 13 (25%) in limbs undergoing amputation (P = 0.001 for association of thrombosis with amputation). CONCLUSION: GC are common among LE bypass grafts in combat casualties but are not associated with limb loss. Thrombosis is predominantly early and is associated with amputation. Closer attention to ensuring early patency may improve limb salvage.

Conversion of the Abdominal Aortic and Junctional Tourniquet (AAJT) to Infrarenal Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) Is Practical in a Swine Hemorrhage Model.

BACKGROUND: Two methods of controlling pelvic and inguinal hemorrhage are the Abdominal Aortic and Junctional Tourniquet (AAJT; Compression Works) and resuscitative endovascular balloon occlusion of the aorta (REBOA). The AAJT can be applied quickly, but prolonged use may damage the bowel, inhibit ventilation, and obstruct surgical access. REBOA requires technical proficiency but avoids many of the complications associated with the AAJT. Conversion of the AAJT to REBOA would allow for field hemorrhage control with mitigation of the morbidity associated with prolonged AAJT use. METHODS: Yorkshire male swine (n = 17; 70-90kg) underwent controlled 40% hemorrhage. Subsequently, AAJT was placed on the abdomen, midline, 2cm superior to the ilium, and inflated. After 1 hour, the animals were allocated to an additional 30 minutes of AAJT inflation (continuous AAJT occlusion [CAO]), REBOA placement with the AAJT inflated (overlapping aortic occlusion [OAO]), or REBOA placement following AAJT removal (sequential aortic occlusion [SAO]). Following removal, animals were observed for 3.5 hours. RESULTS: No statistically significant differences in survival, blood pressure, or laboratory values were found following intervention. Conversion to REBOA was successful in all animals but one in the OAO group. REBOA placement time was 4.3 ± 2.9 minutes for OAO and 4.1 ± 1.8 minutes for SAO (p = .909). No animal had observable intestinal injury. CONCLUSIONS: Conversion of the AAJT to infrarenal REBOA is practical and effective, but access may be difficult while the AAJT is applied.

Endovascular Embolization Techniques in a Novel Swine Model of Fatal Uncontrolled Solid Organ Hemorrhage and Coagulopathy.

BACKGROUND: Endovascular embolization is increasingly used in treating traumatic hemorrhage and other applications. No endovascular-capable translational large animal models exist and coagulopathy's effect on embolization techniques is unknown. We developed a coagulation-adaptable solid organ hemorrhage model in swine for investigation of embolization techniques. METHODS: Anesthetized swine (n = 26, 45 ± 3 kg) had laparotomy and splenic externalization. Half underwent 50% isovolemic hemodilution with 6% hetastarch and cooling to 33-35°C (COAG group). All had controlled 20 mL/kg hemorrhage and endovascular access to the proximal splenic artery with a 4F catheter via a right femoral sheath. Splenic transection and 5 min free bleeding were followed by treatment (n = 5/group) with 5 mL gelfoam slurry, three 6-mm coils, or no treatment (n = 3, control). Animals received 15 mL/kg plasma resuscitation and were monitored for 6 hr. Splenic blood loss was continuously measured and angiograms were performed at specified times. RESULTS: Coagulopathy was successfully established in COAG animals. Pre-treatment blood loss was greater in COAG (11 ± 6 mL/kg) than non-COAG (7 ± 3 mL/kg, P = 0.04) animals. Splenic hemorrhage was universally fatal without treatment. Non-COAG coil survival was 4/5 (326 ± 75 min) and non-COAG Gelfoam 3/5 (311 ± 67 min) versus non-COAG Control 0/3 (82 ± 18 min, P < 0.05 for both). Neither COAG Coil (0/5, 195 ± 117 min) nor COAG Gelfoam (0/5, 125 ± 32 min) treatment improved survival over COAG Control (0/3, 56 ± 19 min). Post-treatment blood loss was 4.6 ± 3.4 mL/kg in non-COAG Coil and 4.6 ± 2.9 mL/kg in non-COAG Gelfoam, both lower than non-COAG Control (18 ± 1.3 mL/kg, P = 0.05). Neither COAG Coil (8.4 ± 5.4 mL/kg) nor COAG Gelfoam (15 ± 11 ml/kg) had significantly less blood loss than COAG Control (20 ± 1.2 mL/kg). Both non-COAG treatment groups had minimal blood loss during observation, while COAG groups had ongoing slow blood loss. In the COAG Gelfoam group, there was an increase in hemorrhage between 30 and 60 min following treatment. CONCLUSIONS: A swine model of coagulation-adaptable fatal splenic hemorrhage suitable for endovascular treatment was developed. Coagulopathy had profound negative effects on coil and gelfoam efficacy in controlling bleeding, with implications for trauma and elective embolization procedures.