Outcomes of Visceral Arterial Interposition Graft Reconstruction for Locally Advanced Pancreatic Cancer.

OBJECTIVE: The aim of this study is to determine perioperative outcomes and the patency of interposition conduits for visceral arterial reconstruction in this setting. SUMMARY BACKGROUND DATA: Visceral arterial encasement in locally advanced pancreatic cancer was historically a contraindication for surgery. With modern effective neoadjuvant strategies, our recent experience has made advanced vascular resection and reconstruction feasible in selected patients. METHODS: A retrospective review was performed of patients undergoing pancreatic tumor resection with en bloc arterial resection and interposition revascularization between 6/2002-10/2022. Endpoints included graft patency, vascular-related complications, reinterventions, morbidity, and mortality. RESULTS: Visceral arterial reconstruction with interposition grafting was performed in 111 patients undergoing en bloc arterial resections for pancreatic cancer. Graft types included autologous arterial conduits (n=66, 58 superficial femoral artery (SFA) and 8 splenic artery), cryopreserved arterial allografts (n=24), autologous saphenous veins (n=12), synthetic conduits (n=8), and composite autologous artery and synthetic (n=1). Perioperative 90-day mortality decreased significantly over time to 5% in the last six years. Vascular complications related to arterial reconstruction occurred in 11% (n=12) and included pseudoaneurysm (n=6), graft thrombus (n=2), stenosis requiring reintervention (n=2), hepatic failure (n=1), and hepatic and intestinal ischemia (n=1). Nine (8%) patients underwent vascular-related reinterventions. After median follow-up of 17-months, primary patency was 81% for the entire cohort and was highest in the SFA group (95%). The donor limb/harvest site complication rate was 8% with 100% primary patency. CONCLUSION: Visceral arterial resection with interposition reconstruction for locally advanced pancreatic cancer can be performed with acceptable vascular morbidity and durable patency. Autologous SFA was the most suitable conduit for reconstructions in our experience, with highest primary patency.

Cryopreserved arterial allografts vs autologous vein for arterial reconstruction in infected fields.

OBJECTIVE: Peripheral arterial infections are rare and difficult to treat when an in situ reconstruction is required. Autologous vein (AV) is the conduit of choice in many scenarios. However, cryopreserved arterial allografts (CAAs) are an alternative. We aimed to assess our experience with CAAs and AVs for reconstruction in primary and secondary peripheral arterial infections. METHODS: Data from patients with peripheral arterial infections undergoing reconstruction with CAA or AV from January 2002 through August 2022 were retrospectively analyzed. Patients with aortic- or iliac-based infections were excluded. RESULTS: A total of 42 patients (28 CAA, 14 AV) with a mean age of 65 and 69 years, respectively, were identified. Infections were secondary in 31 patients (74%) and primary in 11 (26%). Secondary infections included 10 femoral-femoral grafts, 10 femoropopliteal or femoral-distal grafts, five femoral patches, four carotid-subclavian grafts, one carotid-carotid graft, and one infected carotid patch. Primary infection locations included six femoral, three popliteal, and two subclavian arteries. In patients with lower extremity infections, associated groin infections were present in 19 (56%). Preoperative blood cultures were positive in 17 patients (41%). AVs included saphenous vein in eight and femoral vein in six. Intraoperative cultures were negative in nine patients (23%), polymicrobial in eight (21%), and monomicrobial in 22 (56%). Thirty-day mortality occurred in four patients (10%), two due to multisystem organ failure, one due to graft rupture causing acute blood loss and myocardial infarction, and one due to an unknown cause post-discharge. Median follow-up was 20 months and 46 months in the CAA and AV group, respectively. Graft-related reintervention was performed in six patients in the CAA group (21%) and one patient in the AV group (7%). Freedom from graft-related reintervention rates at 3 years were 82% and 92% in the CAA and AV group, respectively (P = .12). Survival rates at 1 and 3 years were 85% and 65% in the CAA group and 92% and 84% in the AV group (P = .13). Freedom from loss of primary patency was similar with 3-year rates of 77% and 83% in the CAA and AV group, respectively (P = .25). No patients in either group were diagnosed with reinfection. CONCLUSIONS: CAAs are an alternative conduit for peripheral arterial reconstructions when AV is not available. Although there was a trend towards higher graft-related reintervention rates in the CAA group, patency is similar and reinfection is rare.

Outcomes of lower extremity arterial bypass using the Human Acellular Vessel in patients with chronic limb-threatening ischemia.

OBJECTIVE: Patients with chronic limb-threatening ischemia (CLTI) and no great saphenous vein to use as a conduit for arterial bypass have a high risk for amputation despite advances in medical and endovascular therapies. This report presents findings from a U.S. Food and Drug Administration (FDA) supported study of the Human Acellular Vessel (HAV) (Humacyte Inc.) used as a conduit for arterial bypass in patients with CLTI and inadequate or absent autologous conduit. METHODS: The HAV is a 6-mm, 40-cm vessel created from human vascular smooth muscle cells seeded onto a polyglycolic acid scaffold pulsed in a bioreactor for 8 weeks as cells proliferate and the scaffold dissolves. The resultant vessel is decellularized, creating a nonimmunogenic conduit composed of collagen, elastin, and extracellular matrix. The FDA issued an Investigational New Drug for an intermediate-sized, single-center study of the HAV under the agency's Expanded Access Program in patients with advanced CLTI and inadequate or absent autologous conduit. Technical results and clinical outcomes were analyzed and reported. RESULTS: Between March 2021 and July 2023, 29 patients (20 males; mean age, 71 ± 11 years) underwent limb salvage operation using the HAV as a bypass conduit. Most patients had advanced CLTI (Rutherford class 5/6 in 72%; wound, ischemia, and foot infection stage 3/4 in 83%), and 97% had previously failed revascularization(s) of the extremity. Two HAVs were sewn together to attain the needed bypass length in 24 patients (83%). Bypasses were to tibial arteries in 23 patients (79%) and to the popliteal artery in 6 (21%). Technical success was 100%, and the 30-day mortality rate was 7% (2 patients). With 100% follow-up (median, 9.3 months), the limb salvage rate was 86% (25/29 patients). There were 16 reinterventions to restore secondary patency, of which 15 (94%) were successful. Primary and secondary patency of the HAV at 9 months were 59% and 71%, respectively. CONCLUSIONS: The HAV has demonstrated short- to intermediate-term safety and efficacy as an arterial bypass conduit in a complex cohort of patients with limb-threatening ischemia and no autologous options. This experience using the FDA's Expanded Access Program provides real-world data to inform regulatory deliberations and future trials of the HAV, including the study of the vessel as a first-line bypass conduit in less severe cases of chronic limb ischemia.

Natural history and long-term outcomes of medically managed Type B intramural hematoma.

OBJECTIVE: Type B intramural hematoma (IMH) is often managed medically, yet may progress to dissection, aneurysmal dilation, or rupture. The aim of this study was to report the natural history of medically managed Type B IMH, and factors associated with progression. METHODS: We reviewed patients with medically managed Type B IMH between January 1995 to December 2022 at a single center. Any patients with immediate surgical or endovascular intervention were excluded. Demographic profiles, comorbidities, imaging, and follow-up details were reviewed. Patients were divided into two groups: Group 1 had isolated IMH, and Group 2 had IMH along with aneurysm or dissection at the time of presentation. On follow-up, progression was defined as degeneration to aneurysm/dissection or increase in the thickness of IMH in Group 1. In Group 2, progression was an increase in the size of aneurysm or development of new dissection. RESULTS: Of 104 patients with Type B IMH during the study period, 92 were medically managed. The median age was 77 years, and 45 (48.9%) were females. Comorbidities included hypertension (83.7%), hypercholesterolemia (44.6%), and active smoking (47.8%). Mean Society for Vascular Surger comorbidity score was 6.3. Mean IMH thickness and aortic diameter at presentation were 8.9 mm and 38.3 mm, respectively. Median follow-up was 55 months. Overall survival at 1 year and 5 years was 85.8% and 61.9%, respectively. During follow-up, 19 patients (20.7%) required intervention, more common in Group 2 (Group 1, 8/66; 12.3% vs Group 2, 11/26; 42.3%; P = .001). This resulted in higher freedom from intervention in Group 1 at 1 year (93.5% vs 62.7%) and 5 years (87.5% vs 51.1%; P < .001). Indication for intervention was dissection (n = 4), aneurysm (n = 12), and progression of IMH (n = 3). In Group 1, progression was seen in 25 (37.9%), three (4.5%) remained stable, 29 (43.9%) had complete resolution of IMH, and nine patients were lost to follow-up. In Group 2, 11 patients (42.3%) had progression, seven (26.9%) remained stable, and eight were lost to follow-up. IMH thickness at presentation >7.2 mm is associated with both increased odds of progression (odds ratio, 3.3; 95% confidence interval, 1.2-11.1; P = .03) and intervention (odds ratio, 5.5; 95% confidence interval, 1.3-36.9; P = .03) during the follow-up. CONCLUSIONS: Although many patients with Type B IMH managed medically stabilize or regress, progression or need for intervention can occur in up to 40% of cases. This is associated with the presence of aneurysm, dissection, and IMH thickness. Long-term follow-up is mandatory as late interventions occur, particularly for higher risk patients.

Comparative outcomes of arterial bypass using the human acellular vessel and great saphenous vein in patients with chronic limb ischemia.

OBJECTIVE: The Human Acellular Vessel (HAV) is a novel, off-the-shelf biologic conduit being evaluated for arterial reconstructions. Regulatory studies in peripheral arterial disease (PAD) to date have consisted of single-arm cohorts with no comparator groups to contrast performance against established standards. This study aimed to compare outcomes of the HAV with autologous great saphenous vein (GSV) in patients with advanced PAD undergoing infrageniculate bypass. METHODS: Patients with advanced PAD and no autologous conduit who underwent bypass with the 6-mm diameter HAV (Group 1; n = 34) (March 2021-February 2024) were compared with a multicenter historical cohort who had bypass with single-segment GSV (group 2; n = 88) (January 2017-December 2022). The HAV was used under an Investigational New Drug protocol issued by the Food and Drug Administration (FDA) under the agency's Expanded Access Program. RESULTS: Demographics were comparable between groups (mean age 69 ± 10 years; 71% male). Group 1 had higher rates of tobacco use (37 pack-years vs 28 pack-years; P = .059), coronary artery disease (71% vs 43%; P = .007), and prior coronary artery bypass grafting (38% vs 14%; P = .003). Group 1 had more patients classified as wound, ischemia, and foot infection clinical stage 4 (56% vs 33%; P = .018) and with previous index leg revascularizations (97% vs 53%; P < .001). Both groups had a similar number of patients with chronic limb-threatening ischemia (Rutherford class 4-6) (88% vs 86%; P = .693) and Global Anatomic Staging System stage III (91% vs 96%; P = .346). Group 1 required a composite conduit (two HAV sewn together) in 85% of bypasses. The tibial vessels were the target in 79% of group 1 and 100% of group 2 (P < .001). Group 1 had a lower mean operative time (364 minutes vs 464 minutes; P < .001). At a median of 12 months, major amputation-free survival (73% vs 81%; P = .55) and overall survival (84% vs 88%; P = .20) were comparable. Group 1 had lower rates of primary patency (36% vs 50%; P = .044), primary-assisted patency (45% vs 72%; P = .002), and secondary patency (64% vs 72%; P = .003) compared with group 2. CONCLUSIONS: Implanted under Food and Drug Administration Expanded Access provisions, the HAV was more likely to be used in redo operations and cases with more advanced limb ischemia than GSV. Despite modest primary patency, the HAV demonstrated resilience in a complex cohort with no autologous conduit options, achieving good secondary patency and providing major amputation-free survival comparable with GSV at 12 months.

Implications and late outcomes of type II endoleaks after endovascular aneurysm repair.

OBJECTIVE: Type II endoleaks (T2ELs) are the most common cause of reintervention after endovascular aneurysm repair (EVAR). Although most resolve spontaneously, the long-term implications of T2ELs remain elusive. We aim to evaluate the impact of persistent and late T2ELs on clinical outcomes after EVAR. METHODS: This was a single-institution retrospective review of patients who underwent EVAR for degenerative infrarenal abdominal aortic aneurysm between January 2010 and June 2022 with no type I (T1EL) or III (T3EL) endoleak seen at EVAR completion. Patients were categorized based on T2EL status. Group 1 included patients with never detected or transient T2ELs (detected at EVAR completion but not after). Group 2 encompassed persistent T2ELs (seen at EVAR completion and again during follow-up) and late T2ELs (detected for the first time at any point during follow-up). Time-to-event analysis was conducted using a time-dependent approach to T2EL status. Primary outcomes included freedom from sac enlargement (SE), aneurysm-related reinterventions, and overall survival. RESULTS: A total of 803 patients met inclusion criteria. Group 1 included 418 patients (52%), of which 85% had no T2ELs and 15% had transient T2ELs. Group 2 had 385 patients; 23% had persistent T2ELs, and 77% developed a new T2EL. Patients in group 1 had a higher prevalence of smoking (88% vs 83%; P < .001), chronic obstructive pulmonary disease (33% vs 25%; P = .008), chronic kidney disease (13% vs 8%; P = .021), and a higher mean Society for Vascular Surgery score (7 vs 6 points; P = .049). No differences were found in aneurysm diameter or morphology. Mean follow-up was 5 years for the entire cohort. In Group 2, 58 patients (15%) underwent T2EL treatment, most commonly transarterial embolization. At 10 years after EVAR, Group 2 was associated with lower freedom from SE (P < .001) and abdominal aortic aneurysm-related reinterventions (P < .001) and comparable overall survival (P = .42). More T1ELs were detected during follow-up in Group 2 (6 [1%] vs 20 [5%]; P = .004), with 15 (75%) of these detected at a median of 3 years after the T2EL. No difference between groups was observed in explant (0.7% vs 2.1%; P = .130) or aneurysm rupture (0.5% vs 1.3%; P = .269) rates. CONCLUSIONS: One-half of patients treated with infrarenal EVAR developed persistent/late T2ELs, which are associated with a higher risk of SE and reinterventions. No difference in overall survival or aneurysm rupture risk was seen at 10 years, based on T2EL status or T2EL intervention. A conservative approach to T2ELs may be appropriate for most patients with absent T1ELs or T3ELs.

Therapeutic Interventions and Outcomes in Civilian and Military Isolated Gunshot Wounds to the Head: A Department of Defense Trauma Registry and ACS TQIP-matched Study.

OBJECTIVE: The purpose of this study was to compare therapeutic strategies and outcomes, following isolated gunshot wounds of the head, between military and civilian populations. BACKGROUND: Recent military conflicts introduced new concepts in trauma care, including aggressive surgical intervention in severe head trauma. METHODS: This was a cohort-matched study, using the civilian Trauma Quality Improvement Program (TQIP) database of the American College of Surgeons (ACS) and the Department of Defense Trauma Registry (DoDTR), during the period 2013 to 2016. Included in the study were patients with isolated gunshots to the head. Exclusion criteria were dead on arrival, civilians transferred from other hospitals, and patients with major extracranial associated injuries (body area Abbreviated Injury Scale >3). Patients in the military database were propensity score-matched 1:3 with patients in the civilian database. RESULTS: A total of 136 patients in the DoDTR database were matched for age, sex, year of injury, and head Abbreviated Injury Scale with 408 patients from TQIP. Utilization of blood products was significantly higher in the military population ( P <0.001). In the military group, patients were significantly more likely to have intracranial pressure monitoring (17% vs 6%, P <0.001) and more likely to undergo craniotomy or craniectomy (34% vs 13%, P <0.001) than in the civilian group. Mortality in the military population was significantly lower (27% vs 38%, P =0.013). CONCLUSIONS: Military patients are more likely to receive blood products, have intracranial pressure monitoring and undergo craniectomy or craniotomy than their civilian counterparts after isolated head gunshot wounds. Mortality is significantly lower in the military population. LEVEL OF EVIDENCE: Level III-therapeutic.

Clinical presentation, operative management, and long-term outcomes of rupture after previous abdominal aortic aneurysm repair.

OBJECTIVE: The aim of the present study was to evaluate the presentation trends, intervention, and survival of patients who had been treated for late abdominal aortic aneurysm rupture (LAR) after open repair (OR) or endovascular aortic aneurysm repair (EVAR). METHODS: We reviewed the clinical data from a single-center, retrospective database for patients treated for LAR from 2000 to 2020. The end points were the 30-day mortality, major postoperative complication, and survival. The outcomes between LAR managed with EVAR (group I) vs OR were compared (group II). RESULTS: Of 390 patients with infrarenal aortic rupture, 40 (10%) had experienced aortic rupture after prior aortic repair and comprised the LAR cohort (34 men; age 78 ± 8 years). LAR had occurred before EVAR in 30 and before OR in 10 patients. LAR was more common in the second half of the study with 32 patients after 2010. LAR after prior OR was secondary to ruptured para-anastomotic pseudoaneurysms. After initial EVAR, LAR had occurred despite reintervention in 17 patients (42%). The time to LAR was shorter after prior EVAR than after OR (6 ± 4 vs 12 ± 4 years, respectively; P = .003). Treatment for LAR was EVAR for 25 patients (63%; group I) and OR for 15 (37%, group II). LAR after initial OR was managed with endovascular salvage for 8 of 10 patients. Endovascular management was more frequent in the latter half of the study period. In group I, fenestrated repair had been used for seven patients (28%). Salvage for the remaining cases was feasible with EVAR, aortic cuffs, or limb extensions. The incidence of free rupture, time to treatment, 30-day mortality (8% vs 13%; P = .3), complications (32% vs 60%; P = .1), and disposition were similar between the two groups. Those in group I had had less blood loss (660 vs 3000 mL; P < .001) and less need for dialysis (0% vs 33%; P < .001) than those in group II. The median follow-up was 21 months (interquartile range, 6-45 months). The overall 1-, 3-, and 5-year survival was 76%, 52%, and 41%, respectively, and was similar between groups (28 vs 22 months; P = .48). Late mortality was not related to the aorta. CONCLUSIONS: LAR after abdominal aortic aneurysm repair has been encountered more frequently in clinical practice, likely driven by the frequency of EVAR. However, most LARs, including those after previous OR, can now be salvaged with endovascular techniques with lower morbidity and mortality.

Cryopreserved arterial allografts vs rifampin-soaked Dacron for the treatment of infected aortic and iliac grafts.

OBJECTIVE: Aortic and iliac graft infections remain complex clinical problems with high mortality and morbidity. Cryopreserved arterial allografts (CAAs) and rifampin-soaked Dacron (RSD) are options for in situ reconstruction. This study aimed to compare the safety and effectiveness of CAA vs RSD in this setting. METHODS: Data from patients with aortic and iliac graft infections undergoing in situ reconstruction with either CAA or RSD from January 2002 through August 2022 were retrospectively analyzed. Our primary outcomes were freedom from graft-related reintervention and freedom from reinfection. Secondary outcomes included comparing trends in the use of CAA and RSD at our institution, overall survival, perioperative mortality, and major morbidity. RESULTS: A total of 149 patients (80 RSD, 69 CAA) with a mean age of 68.9 and 69.1 years, respectively, were included. Endovascular stent grafts were infected in 60 patients (41 CAA group and 19 RSD group; P ≤ .01). Graft-enteric fistulas were more common in the RSD group (48.8% RSD vs 29.0% CAA; P ≤ .01). Management included complete resection of the infected graft (85.5% CAA vs 57.5% RSD; P ≤ .01) and aortic reconstructions were covered in omentum in 57 (87.7%) and 63 (84.0%) patients in the CAA and RSD group, respectively (P = .55). Thirty-day/in-hospital mortality was similar between the groups (7.5% RSD vs 7.2% CAA; P = 1.00). One early graft-related death occurred on postoperative day 4 due to CAA rupture and hemorrhagic shock. Median follow-up was 20.5 and 21.5 months in the CAA and RSD groups, respectively. Overall post-discharge survival at 5 years was similar, at 59.2% in the RSD group and 59.0% in the CAA group (P = .80). Freedom from graft-related reintervention at 1 and 5 years was 81.3% and 66.2% (CAA) vs 95.6% and 92.5% (RSD; P = .02). Indications for reintervention in the CAA group included stenosis (n = 5), pseudoaneurysm (n = 2), reinfection (n = 2), occlusion (n = 2), rupture (n = 1), and graft-limb kinking (n = 1). In the RSD group, indications included reinfection (n = 3), occlusion (n = 1), endoleak (n = 1), omental coverage (n = 1), and rupture (n = 1). Freedom from reinfection at 1 and 5 years was 98.3% and 94.9% (CAA) vs 92.5% and 87.2% (RSD; P = .11). Two (2.9%) and three patients (3.8%) in the CAA and RSD group, respectively, required graft explantation due to reinfection. CONCLUSIONS: Aorto-iliac graft infections can be managed safely with either CAA or RSD in selected patients for in situ reconstruction. However, reintervention was more common with CAA use. Freedom from reinfection rates in the RSD group was lower, but this was not statistically significant. Conduit choice is associated with long-term surveillance needs and reinterventions.

An International Expert-Based CONsensus on Indications and Techniques for aoRtic balloOn occLusion in the Management of Ruptured Abdominal Aortic Aneurysms (CONTROL-RAAA).

OBJECTIVE: To report on the recommendations of an expert-based consensus on the indications, timing, and techniques of aortic balloon occlusion (ABO) in the management of ruptured abdominal aortic aneurysms (rAAA). METHODS: Eleven facilitators created appropriate statements regarding the study issues that were voted on using a 4-point Likert scale with open-comment fields, by a selected panel of international experts (vascular surgeons and interventional radiologists) using a 3-round modified Delphi consensus procedure (study period: January-April 2023). Based on the experts' responses, only the statements reaching grade A (full agreement ≥75%) or B (overall agreement ≥80% and full disagreement <5%) were included in the final study report. The consistency of each round's answers was also graded using Cohen's kappa, the intraclass correlation coefficient, and, in case of double resubmission, Fleiss kappa. RESULTS: Sixty-three experts were included in the final analysis and voted on 25 statements related to indication and timing (n=6), and techniques (n=19) of ABO in the setting of rAAA. Femoral sheath or ABO should be preferably placed in the operating room, via a percutaneous transfemoral access, on a stiff wire (grade B, consistency I), ABO placement should be suprarenal and last less than 30 minutes (grade B, consistency II), postoperative peripheral vascular status (grade A, consistency II) and laboratory testing every 6 to 12 hours (grade B, consistency) should be assessed to detect complications. Formal training for ABO should be implemented (grade B, consistency I). Most of the statements in this international expert-based Delphi consensus study might guide current choices for indications, timing, and techniques of ABO in the management of rAAA. Clinical practice guidelines should incorporate dedicated statements that can guide clinicians in decision-making. CONCLUSIONS: At arrival and during both open or endovascular procedures for rAAA, selective use of intra-aortic balloon occlusion is recommended, and it should be performed preferably by the treating physician in aortic pathology. CLINICAL IMPACT: This is the first consensus study of international vascular experts aimed at defining the indications, timing, and techniques of optimal use of ABO in the clinical setting of rAAA. Aortic occlusion by endovascular means (or ABO) is a quick procedure in properly trained hands that may play an important role as a temporizing measure until the definitive aortic repair is achieved, whether by endovascular or open means. Since data on its use in hemodynamically unstable patients are limited in the literature, owing to practical challenges in the performance of well-conducted prospective studies, understanding real-world use by experts is of importance in addressing critical issues and identifying main gaps in knowledge.

Midterm Clinical Outcomes of Retrograde Open Mesenteric Stenting for Mesenteric Ischemia.

BACKGROUND: Retrograde open mesenteric stenting (ROMS) has become a mainstay in treatment of mesenteric ischemia; however, follow-up in contemporary studies is limited. METHODS: A single-center retrospective review of patients undergoing ROMS from 2007 to 2020 was conducted. Demographics, presentation, and procedural details were reviewed. End points were morbidity and mortality, technical success, primary patency, reinterventions, and freedom from clinical recurrence. RESULTS: ROMS was performed in 34 patients, 19 female (56%). Mean age was 71 ± 10 years. Eighteen patients (53%) presented with acute mesenteric ischemia (AMI), 11 (32%) with acute-on-chronic, and 5 (15%) with chronic mesenteric ischemia. Etiology was chronic atherosclerosis with/without in-situ thrombosis in 28 patients (82%), superior mesenteric artery dissection in 3, and 1 each with embolic, vasculitic, and nonocclusive ischemia. Four patients (12%) had prior mesenteric procedures (3 Celiac/1 superior mesenteric artery stent) and 1 had unsuccessful transbrachial stenting attempt. Technical success, defined as successful stenting through a retrograde approach was attained in 31 patients (91%), with the 3 remaining patients treated with transbrachial stenting in 2 and iliomesenteric bypass in 1. Covered stents were used in 21 patients (64%) with or without stent extension with bare-metal stents. Eight patients (23%) required thromboembolectomy and 9 (26%) underwent patch angioplasty. Thirty-day mortality rate was 35%, all in patients with AMI (10) or acute-on-chronic (2). Eighteen patients (53%) underwent bowel resection, all presenting acutely. Early reinterventions within the first 30 days were required in 5 patients (15%), including 2 redo ROMS with thrombectomy and endarterectomy, 2 percutaneous stent extensions, and 1 aortic septum fenestration with coiling of a jejunal branch pseudoaneurysm. With a median follow-up of 3.7 (interquartile range: 0.8-5.0) years, in patients surviving discharge, 5 required reintervention yielding freedom from reintervention rates of 87% at 1 year and 71% at 3 years. All postdischarge reinterventions were endovascular with no conversion to bypass. The overall 1-year and 3-year primary patency rates were 70% and 61% (primary-assisted patency at 1 and 3 years was 87% and secondary patency at 1 and 3 years was 97%). The freedom from symptom recurrence was 95% at 1 and 3 years. CONCLUSIONS: ROMS carries high rates of technical success in patients with mesenteric ischemia, despite a high chronic atherosclerotic burden. Although mid-term patency rates are acceptable, AMI is still associated with high early morbidity and mortality, with high rates of associated bowel resection. ROMS is a valuable tool in the armamentarium of vascular surgeons.

Lower Extremity Extracorporeal Distal Revascularization in a Swine Model of Prolonged Extremity Ischemia.

BACKGROUND: Acute arterial occlusion of the lower extremity is a time-dependent emergency that requires prompt revascularization. Lower extremity extracorporeal distal revascularization (LEEDR) is a technique that can be initiated bedside when definitive therapy is delayed. The aim of this study is to evaluate this technique in a swine model of prolonged extremity ischemia. METHODS: Anesthetized swine underwent right femoral and left posterior tibial artery cannulation, left iliac venous flow monitoring (mL/min), and continuous left anterior compartment pressure (CP) monitoring (mm Hg). The iliac artery was clamped for 6 hr. LEEDR animals underwent 5 hr of extracorporeal femoral-to-tibial blood flow at 150 mL/min; controls had no intervention. At 6 hr, LEEDR was discontinued, iliac flow restored, and anterior CP monitored for 3 hr. RESULTS: Baseline characteristics were similar across both the groups. Iliac clamping saw an expected fall in iliac venous flow (258 ± 30 to 82 ± 19; P < 0.001). LEEDR resulted in a rise in iliac venous flow (82 ± 20 to 181 ± 16; P < 0.001); control arm flow remained reduced (71 ± 8; P < 0.001). Once inflow was restored, venous flow returned to baseline. Revascularization provoked a higher peak CP in the control arm versus in the LEEDR group (25 ± 5 vs. 6 ± 1; P = 0.02). CONCLUSIONS: An extracorporeal circuit can temporarily revascularize an extremity in a swine model of prolonged ischemia, mitigating reperfusion injury and maintaining normal CPs. This concept should undergo further evaluation as a bedside tool to mitigate extremity ischemia prior to definitive revascularization.

Cryopreserved Arterial Allografts Versus Rifampin-Soaked Dacron for the Treatment of Infected Aortic and Iliac Aneurysms.

BACKGROUND: Infected aortic and iliac artery aneurysms are challenging to treat. Cryopreserved arterial allografts (CAAs) or rifampin-soaked Dacron (RSD) are standard options for in situ reconstruction. Our aim was to compare the safety and effectiveness of CAA versus RSD for these complex pathologies. METHODS: This is a retrospective review of infected iliac, abdominal, and thoracoabdominal aortic aneurysms treated with either CAAs or RSD between 2002 and 2022 at our institution. The diagnosis was confirmed by intraoperative, radiologic, or microbiological evidence of aortic infection. Perioperative events, 30-day and long-term mortality, reinfection, and reintervention were analyzed. RESULTS: Thirty patients (17 CAA, 13 RSD) with a mean age of 61 and 68 years, respectively, were identified. The infected aneurysm was most commonly suprarenal or infrarenal. Culture-negative infections were present in 47% of the CAA group and 54% in the RSD group. Early major morbidity was 57% and 54% for the CAA and RSD, respectively. Thirty-day mortality was similar between groups (18% vs. 23% CAA vs. RSD, P ≥ 0.99). Median follow-up was longer in the RSD group (14.5 months vs. 13 months). Overall survival at 1 and 5 years was 80.8% and 64.8% in the CAA group and 69.2% and 57.7% in the RSD group. Reinterventions only occurred with CAA repairs and indications included graft occlusion (2), multiple pseudoaneurysms and reinfection (1), and hemorrhagic shock caused by graft rupture (1). Freedom from reintervention at 1 and 3 years was 87.5% and 79.5% (CAA group) versus 100% and 100% (RSD, P = 0.06). Freedom from reinfection at 1 year was 100% in both groups, while at 3 years it was 90.9% for the CAA group and 100% for the RSD group (P = 0.39). CONCLUSIONS: Infected aortic and iliac aneurysms have high early morbidity and mortality. CAA and RSD had similar outcomes in our series; CAA trended toward higher reintervention rates. Both remain viable options for complex scenarios but require close surveillance.

Impact of Ischemia Duration on Lower Limb Salvage in Combat Casualties.

INTRODUCTION: The 6-hour threshold to revascularization of an ischemic limb is ubiquitous in the trauma literature, however, contemporary evidence suggests that this threshold should be less. This study aims to characterize the relationship between the duration of limb ischemia and successful limb salvage following lower extremity arterial trauma. METHODS: This is a cohort study of the United States and UK military service members injured while serving in Iraq or Afghanistan between 2003 and 2013. Consecutive patients who sustained iliac, femoral, or popliteal artery injuries, and underwent surgery to attempt revascularization, were included. The association between limb outcome and the duration of limb ischemia was assessed using the Kaplan-Meier method. RESULTS: One hundred twenty-two patients (129 limbs) who sustained iliac (2.3%), femoral (56.6%), and popliteal (41.1%) arterial injuries were included. Overall, 87 limbs (67.4%) were successfully salvaged. The probability of limb salvage was 86.0% when ischemia was ≤1 hour; 68.3% when between 1 and 3 hours; 56.3% when between 3 and 6 hours; and 6.7% when >6 hours ( P <0.0001). Shock more than doubled the risk of failed limb salvage [hazard ratio=2.42 (95% confidence interval: 1.27-4.62)]. CONCLUSIONS: Limb salvage is critically dependent on the duration of ischemia with a 10% reduction in the probability of successful limb salvage for every hour delay to revascularization. The presence of shock significantly worsens this relationship. Military trauma systems should prioritize rapid hemorrhage control and early limb revascularization within 1 hour of injury.

Next-Generation REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta) Device Precisely Achieves Targeted Regional Optimization in a Porcine Model of Hemorrhagic Shock.

INTRODUCTION: Limitations such as time-dependent distal ischemia have slowed the adoption of resuscitative endovascular balloon occlusion of the aorta (REBOA) for noncompressible hemorrhage. Next-generation REBOA technologies may allow for controlled partial flow, known as targeted regional optimization, to reduce distal ischemia. We aimed to characterize the efficacy of one such catheter in a porcine model of lethal hemorrhagic shock. METHODS: Noncompressible hemorrhage from an iliac injury was induced in anesthetized swine (Sus scrofa) (70-90 kg), targeting 30% total blood volume. Animals were then randomized to partial aortic occlusion (PO) with targeted distal mean arterial pressure (MAP) of 35-40 mm of mercury (mm Hg) and complete aortic occlusion (CO) (n = 8 per group) for 90 min. All groups were then resuscitated during a two-h critical care (CC) phase, with flow rate and MAP recorded continuously at the distal infrarenal aorta and proximal carotid artery, and analyzed with two-way repeated measures analysis of variance with S-N-K post-hoc test. RESULTS: During aortic occlusion, MAP distal to the balloon was consistently maintained at 35.8 ± 0.3 mm Hg in the PO group compared to 27.1 ± 0.3 mm Hg in the CO group (P < 0.05), which also corresponded to higher flow rates (202.9 ± 4.8 mL/min PO versus 25.9 ± 0.8 mL/min CO; P < 0.05). MAP proximal to the balloon was significantly higher with CO versus PO (109.2 ± 2.3 mm Hg versus 85.2 ± 2.3 mm Hg; P < 0.05). During the CC phase, distal aortic flow and MAP were not significantly different between groups. However, creatinine returned to baseline levels by the end of the study in the PO group, but not the CO group. One animal died in the CO group, whereas none died in the PO group. CONCLUSIONS: This is the first examination of the next-generation pREBOA-PRO in a porcine model of lethal hemorrhagic shock. We show technical feasibility of this technique to precisely achieve targeted regional optimization without device failure or complication. The ability to titrate balloon inflation and thus distal flow/pressure may extend the therapeutic window of REBOA by mitigating distal ischemia.

Preliminary Experience With the Human Acellular Vessel: A Descriptive Case Series Detailing Early Use of a Bioengineered Blood Vessel for Arterial Repair.

BACKGROUND: An infection-resistant, immediately available conduit for trauma and urgent vascular reconstruction remains a critical need for successful limb salvage. While autologous vein remains the gold standard, vein-limited patients and size mismatch are common issues. The Human Acellular Vessel (HAV) (Humacyte, Inc., Durham, NC) is a bioengineered conduit with off-the-shelf availability and resistance to infection, ideal characteristics for patients with challenging revascularization scenarios. This report describes HAV implantation in patients with complex limb-threatening ischemia and limited conduit options who may have otherwise faced limb loss. METHODS: The Food and Drug Administration (FDA) expanded-access program was used to allow urgent implantation of the HAV for arterial reconstruction. Electronic medical records were reviewed with extraction of relevant data including patient demographics, surgical implantation, patency, infectious complications, and mortality. RESULTS: The HAV was implanted in 8 patients requiring vascular reconstruction. Graft or soft tissue infection was present in 2 patients. One patient with severe penetrating pelvic injury had 4 HAV placed to repair bilateral external iliac artery and vein injuries. There was 1 technical failure due to poor outflow, 2 patients died unrelated to HAV use, and 5 lower extremity bypasses maintained patency at an average of 11.4 months (range: 4-20 months). No HAV infectious complications were identified. CONCLUSIONS: This report is the first United States series describing early outcomes using the HAV under the FDA expanded-access program for urgent vascular reconstruction. The HAV demonstrates resistance to infection, reliable patency, and offers surgeons an immediate option when confronted with complex revascularization scenarios. Assessment of long-term outcomes will be important for future studies.

The functional vascular anatomy of the swine for research.

OBJECTIVES: Swine (Sus Scrofa) are utilized broadly in research settings, given similarities to human vessel size and function; however, there are some important differences for clinicians to understand in order to interpret and perform translational research. This review article uses angiograms acquired in the course of a translational research program to present a description of the functional anatomy of the swine. METHODS: Digital subtraction angiography and computed tomography angiography were obtained throughout the course of multiple studies utilizing power injection with iodinated contrast. Subtracted two-dimensional images and three-dimensional multiplanar reformations were utilized post image acquisition to create maximal intensity projections and three-dimensional renderings of using open-source software (OsiriX). These imaging data are presented along with vessel measurements for reference. RESULTS: An atlas highlighting swine vascular anatomy, with an emphasis on inter-species differences that may influence how studies are conducted and interpreted, was compiled. CONCLUSIONS: Swine are utilized in broad-reaching fields for preclinical research. While many similarities between human and swine vasculature exist, there are important differences to consider when conducting and interpreting research. This review article highlights these differences and presents accompanying images to inform clinicians gaining experience in swine research.

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA): Zone I Balloon Occlusion Time Affects Spinal Cord Injury in the Nonhuman Primate Model.

OBJECTIVES: Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) has been used clinically to limit torso bleeding and restore central perfusion. The objective of this study was to determine the sequelae of prolonged REBOA in a nonhuman primate animal model. SUMMARY BACKGROUND DATA: Prolonged duration of REBOA is associated with adverse clinical outcomes. Threshold occlusion values tied to relative risk have yet to be determined. METHODS: Juvenile baboons were subjected to 40% to 55% total blood volume hemorrhage to achieve profound hypotension and shock. Zone I REBOA was performed for 60 minutes to assess acute injury and survival at 4 hours (group 1; n = 7). Post-REBOA 10-day survival and complications were then compared between 60 minutes (group 2; n = 8) and 30 minutes (group 3; n = 6) REBOA animals. RESULTS: Overall survival was 20/21 (95%). IL-6 and IL-8 were elevated at 1 and 4 hours in group 1 (P = 0.005; P = 0.001). Comparing 60-minute REBOA with 30-minute REBOA, there was (1) hypertension compared with normotension (P = 0.005), (2) increased base deficit (P = 0.003), (3) elevated Troponin I (P = 0.04), and histological evidence of kidney injury (P = 0.004). In addition, group 2 demonstrated paralysis with histopathologic changes of spinal cord ischemia (SCI) in 4/8 (50%), with no SCI in group 3 (P = 0.033). CONCLUSIONS: REBOA limits mortality in the primate model of severe hemorrhagic shock. However, unopposed balloon inflation in the distal thoracic aorta for 60 minutes results in high rates of spinal cord ischemia, an effect mitigated by limiting balloon inflation to 30 minutes.

Temporary intravascular shunt use improves early limb salvage after extremity vascular injury.

OBJECTIVE: The use of temporary intravascular shunts (TIVSs) allow for restoration of distal perfusion and reduce ischemic time in the setting of arterial injury. As a damage control method, adjunct shunts restore perfusion during treatment of life-threatening injuries, or when patients require evacuation to a higher level of care. Single-center reports and case series have demonstrate that TIVS use can extend the opportunity for limb salvage. However, few multi-institutional studies on the topic have been reported. The objective of the present study was to characterize TIVS use through a multi-institutional registry and define its effects on early limb salvage. METHODS: Data from the Prospective Observation Vascular Injury Treatment registry was analyzed. Civilian patients aged ≥18 years who had sustained an extremity vascular injury from September 2012 to November 2018 were included. Patients who had a TIVS used in the management of vascular injury were included in the TIVS group and those who had received treatment without a TIVS served as the control group. An unadjusted comparison of the groups was conducted to evaluate the differences in the baseline and outcome characteristics. Double robust estimation combining logistic regression with propensity score matching was used to evaluate the effect of TIVS usage on the primary end point of limb salvage. RESULTS: TIVS use was identified in 78 patients from 24 trauma centers. The control group included 613 patients. Unmatched analysis demonstrated that the TIVS group was more severely injured (mean ± standard deviation injury severity score, 18.83 ± 11.76 for TIVS vs 14.93 ± 10.46 for control; P = .002) and had more severely mangled extremities (mean ± standard deviation abbreviated injury scale, extremity, score 3.23 ± 0.80 for TIVS vs 2.95 ± 0.87 for control; P = .008). Logistic regression demonstrated that propensity-matched control patients had a three times greater likelihood of amputation compared with the TIVS patients (odds ratio, 3.6; 95% confidence interval, 1.2-11.1; P = .026). Concomitant nerve injury and orthopedic fracture were associated with a greater risk of amputation. The median follow-up for the TIVS group was 12 days (interquartile range, 4-25 days) compared with 9 days (interquartile range, 4-18 days) for the control group. CONCLUSIONS: To the best of our knowledge, the present study is the first multicenter, matched-cohort study to characterize early limb salvage as a function of TIVS use in the setting of extremity vascular injury. Shunts expedite limb perfusion and resulted in lower rates of amputation during the early phase of care. The use of TIVS should be one part of a more aggressive approach to restore perfusion in the most injured patients and ischemic limbs.

Timing of repair of blunt thoracic aortic injuries in the thoracic endovascular aortic repair era.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) is the preferred operative treatment of blunt thoracic aortic injuries (BTAIs). Its use is associated with improved outcomes compared with open surgical repair and nonoperative management. However, the optimal time from injury to repair is unknown and remains a subject of debate across different societal practice guidelines. The purpose of this study was to evaluate national trends in the management of BTAI, with a specific focus on the impact of timing of repair on outcomes. METHODS: Using the National Trauma Data Bank, we identified adult patients with BTAI between 2012 and 2017. Patients with prehospital or emergency department cardiac arrest or incomplete data sets were excluded from analysis. Patients were classified according to timing of repair: group 1, <24 hours; and group 2, ≥24 hours. The primary outcome evaluated was in-hospital mortality; secondary outcomes included overall hospital and intensive care unit length of stay. Multivariable logistic regression was performed to identify independent predictors of mortality. RESULTS: The analysis was completed for 2821 patients who underwent TEVAR for BTAI with known operative times. The overall mortality in the patient cohort was 8.4% (238/2821); 75% of patients undergoing TEVAR were repaired within 24 hours. Mortality was more than twofold greater in group 1 compared with group 2 (9.8% [207/2118] vs 4.4% [31/703]; P = .001). This mortality benefit persisted across injury severity groups and was independent of the presence of serious extrathoracic injuries. Logistic regression analysis, adjusting for age ≥65 years, Glasgow Coma Scale score ≤8, systolic blood pressure ≤90 mm Hg at admission, and serious extrathoracic injuries, showed a higher adjusted mortality in group 1 (odds ratio, 2.54; 95% confidence interval, 1.66-3.91; P = .001). CONCLUSIONS: The majority of patients with BTAI undergo endovascular repair within 24 hours of injury. Patients undergoing delayed repair have improved survival compared with those repaired within the first 24 hours of injury in spite of similar injury patterns and severity. In patients with BTAIs without signs of imminent rupture, delaying endovascular repair beyond 24 hours after injury should be considered.