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.

Targeted Regional Optimization in Action: Dose-dependent End-organ Ischemic Injury with Partial Aortic Occlusion in the Setting of Ongoing Liver Hemorrhage.

INTRODUCTION: Targeted regional optimization (TRO) describes partial resuscitative endovascular balloon occlusion of the aorta strategy that allows for controlled distal perfusion to balance hemostasis and tissue perfusion. This study characterized hemodynamics at specific targeted distal flow rates in a swine model of uncontrolled hemorrhage to determine if precise TRO by volume was possible. METHODS: Anesthetized swine were subjected to liver laceration and randomized into TRO at distal flows of 300 mL/min (n = 8), 500 mL/min (n = 8), or 700 mL/min (n = 8). After 90 min, the animals received damage control packing and were monitored for 6 h. Hemodynamic parameters were measured continuously, and hematology and serologic labs obtained at predetermined intervals. RESULTS: During TRO, the average percent deviation from the targeted flow was lower than 15.9% for all cohorts. Average renal flow rates were significantly different across all cohorts during TRO phase (P < 0.0001; TRO300 = 63.1 ±â€Š1.2; TRO500 = 133.70 ±â€Š1.93; TRO700 = 109.3 ±â€Š2.0), with the TRO700 cohort having less renal flow than TRO500. The TRO500 and TRO700 average renal flow rates inverted during the intensive care unit phase (P < 0.0001; TRO300 = 86.20 ±â€Š0.40; TRO500 = 148.50 ±â€Š1.45; TRO700 = 181.1 ±â€Š0.70). There was higher blood urea nitrogen, creatinine, and potassium in the TRO300 cohort at the end of the experiment, but no difference in lactate or pH between cohorts. CONCLUSION: This study demonstrated technical feasibility of TRO as a strategy to improve outcomes after prolonged periods of aortic occlusion and resuscitation in the setting of ongoing solid organ hemorrhage. A dose-dependent ischemic end-organ injury occurs beginning with partial aortic occlusion that progresses through the critical care phase, with exaggerated effect on renal function.

Targeted Regional Optimization: Increasing the Therapeutic Window for Endovascular Aortic Occlusion In Traumatic Hemorrhage.

ABSTRACT: Resuscitative endovascular balloon occlusion of the aorta (REBOA) allows for effective temporization of exsanguination from non-compressible hemorrhage (NCTH) below the diaphragm. However, the therapeutic window for aortic occlusion is time-limited given the ischemia-reperfusion injury generated. Significant effort has been put into translational research to develop new strategies to alleviate the ischemia-reperfusion injury and extend the application of endoaortic occlusion. Targeted regional optimization (TRO) is a partial REBOA strategy to augment proximal aortic and cerebral blood flow while targeting minimal threshold of distal perfusion beyond the zone of partial aortic occlusion. The objective of TRO is to reduce the degree of ischemia caused by complete aortic occlusion while providing control of distal hemorrhage. This review provides a synopsis of the concept of TRO, pre-clinical, translational experiences with TRO and early clinical outcomes. Early results from TRO strategies are promising; however, further studies are needed prior to large-scale implementation into clinical practice.

A multi-registry analysis of military and civilian penetrating cervical carotid artery injury.

INTRODUCTION: Penetrating cervical carotid artery injury is an uncommon but high-stake scenario associated with stroke and death. The objective of this study was to characterize and compare penetrating carotid injury in the military and civilian setting, as well as provide considerations for management. METHODS: Cohorts with penetrating cervical carotid artery injury from the Department of Defense Trauma Registry (2002-2015) and the American Association for the Surgery of Trauma Prospective Observation Vascular Injury Treatment Registry (2012-2018) were analyzed. A least absolute shrinkage and selection operator multivariate analysis using random forest-based imputation was performed to identify risk factors affecting stroke and mortality. RESULTS: There were a total of 157 patients included in the study, of which 56 (35.7%) were military and 101 (64.3%) were civilian. The military cohort was more likely to have been managed with open surgery (87.5% vs. 44.6%, p < 0.001) and to have had any procedure to restore or maintain flow to the brain (71.4% vs. 35.6%, p < 0.001), while the civilian cohort was more likely to undergo nonoperative management (45.5% vs. 12.5%, p < 0.001). Stroke rate was higher within the military cohort (41.1% vs. 13.9%, p < 0.001); however, mortality did not differ between the groups (12.5% vs. 17.8%, p = 0.52). On multivariate analysis, predictors for stroke were presence of a battle injury (log odds, 2.1; p < 0.001) and internal or common carotid artery ligation (log odds 1.5, p = 0.009). For mortality outcome, protective factors included a high Glasgow Coma Scale on admission (log odds, -0.21 per point; p < 0.001). Increased admission Injury Severity Score was a predictor of mortality (log odds, 0.05 per point; p = 0.005). CONCLUSION: The stroke rate was higher in the military cohort, possibly reflecting complexity of injury; however, there was no difference in mortality between military and civilian patients. For significant injuries, concerted efforts should be made at carotid reconstruction to reduce the occurrence of stroke. LEVEL OF EVIDENCE: Retrospective cohort analysis, level III.

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.

A New Pressure-Regulated, Partial Resuscitative Endovascular Balloon Occlusion of the Aorta Device Achieves Targeted Distal Perfusion.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) reduces blood loss and improves hemodynamics. Complete occlusion results in distal ischemia, limiting its use for prolonged care. This study evaluated two next-generation partial REBOA (pREBOA) catheters and their ability to achieve targeted distal aortic flow. MATERIALS AND METHODS: Swine underwent hemorrhagic shock, complete aortic occlusion, controlled continuous balloon deflation, and targeted distal perfusion (TDP; 300-mL/min) phases. They were randomized into three groups (n = 6/group), one managed with the current ER-REBOA (ER), and two with the new pREBOA technologies: a bilobed (BL) device and a semicompliant pREBOA-PRO (PRP). Hemodynamics including flow rates and mean arterial pressures at the carotid artery and infrarenal aorta were recorded. RESULTS: Hemodynamics were comparable between groups during hemorrhage and complete occlusion phases. During the controlled continuous balloon deflation phase, the distal aortic flow rate strongly correlated with percent balloon volume in BL and PRP groups, suggesting a precise control of distal perfusion. The slope of flow-balloon-volume curves was greater in the ER group than BL and PRP groups, indicating the change in distal aortic flow rate was more sensitive to the balloon volume (less titratable) when using ER. During the TDP phase, variation in distal aortic flow and mean arterial pressure with respect to the target flow was lower in ER and PRP groups, than the BL group. CONCLUSIONS: Pressure-regulated occlusion using the next-generation pREBOA catheters is more controlled than the first-generation ER-REBOA catheter and allow for targeted and precise distal perfusion.

Infraclavicular Thoracic Outlet Decompression Compared to Supraclavicular Thoracic Outlet Decompression for the Management of Venous Thoracic Outlet Syndrome.

BACKGROUND: The treatment of venous thoracic outlet syndrome (VTOS) requires surgical decompression often combined with catheter-directed thrombolysis and venoplasty. Surgical options include transaxillary, supraclavicular, or infraclavicular approaches to first rib resection. The optimal method, however, has yet to be defined. The purpose of this study is to compare the outcomes of patients who underwent infraclavicular versus supraclavicular surgical decompression for VTOS. METHODS: A retrospective review of patients who underwent surgical management for VTOS from December 2010 to November 2017 was performed. During the study period, supraclavicular and infraclavicular approaches were chosen according to surgeon preference. Patient demographics, pre- and postdecompression interventions, perioperative outcomes for each group of patients were analyzed. RESULTS: Thirty patients underwent surgical management of VTOS, of which 15 (50%) underwent infraclavicular decompression and 15 (50%) supraclavicular decompression. The mean age of patients was 32.1 ± 13.6 years and 80% were male. Twenty-six patients (86.7%) presented with thrombotic VTOS. Acute axillosubclavian vein thrombosis was present in 20 (76.9%) of these patients, 10 patients in each group. Subacute or chronic thrombosis was encountered in the remaining 6 (23%) patients, 2 patients in the infraclavicular group and 4 patients in the supraclavicular group. Preoperative thrombolysis was utilized in 7 (46.7%) and 6 (40%) patients in the infraclavicular and supraclavicular groups, respectively (P = 1.00). Patients without postdecompression venography were removed from analysis and included 1 patient in the infraclavicular group and 5 patients in the supraclavicular group. Initial postdecompression venogram, prior to any endovascular intervention, demonstrated a residual axillosubclavian vein stenosis of greater than 50% in 6 (42.9%) patients in the infraclavicular decompression group and 7 (70%) patients in the supraclavicular decompression group (P = 0.24). Crossing the stenosis after surgical decompression was more easily accomplished in the infraclavicular group, 14 (100%) versus 5 (50%), (P = 0.01). Following endovascular venoplasty, calculated residual stenosis greater than 50% was found in 0 (0%) and 3 (30%) patients in the infraclavicular and supraclavicular approaches, respectively (P = 0.047). Infraclavicular thoracic outlet decompression was associated with fewer patients with postoperative symptoms, 0 of 15 (0%) versus 8 of 15 (53.3%), (P = 0.0022), and infraclavicular thoracic outlet decompression demonstrated improved patency, 15 of 15 (100%) versus 8 of 15 (53.3%), (P = 0.028) at a mean combined follow-up of 8.47 ± 10.8 months. CONCLUSIONS: Infraclavicular thoracic outlet decompression for the surgical management of VTOS was associated with fewer postoperative symptoms and improved axillosubclavian vein patency compared to the supraclavicular approach. Prospective analysis is warranted to determine long-term outcomes following infraclavicular decompression.

Tube Thoracostomy Management in the Combat Wounded.

The intent of this study was to characterize the management and subsequent complications of combat injury tube thoracostomies and to determine risk factors for the development of pneumonia (PNA) and retained hemothorax (RH). One hundred fifteen patients with 173 tube thoracostomies met the inclusion criteria and were analyzed. The mean injury severity score was 30.8 + 11.6, 23.5 per cent had traumatic amputations, 49.7 per cent had a hemothorax, and 50.3 per cent had a pneumothorax as indications for tube thoracostomy (TT) placement. Within 24 hours of injury, 89.6 per cent were intubated, the majority (54%) were injured by improvised explosive devices, 35.6 per cent sustained rib fractures, and 12.2 per cent had a diaphragm injury. A mean of 1.5 + 0.7(range 1-4) tube thoracostomies were placed, 18.3 per cent of patients had bilateral tube thoracostomies, and the average TT duration was 6.7 + 3.9 days. The incidence of PNA was 27 per cent (n = 31), RH was 9.6 per cent (n = 11), and empyema was 1.7 per cent (n = 2). Multivariable analysis identified the duration of ventilation [OR 1.2, 95% confidence interval (CI): 1.097-1.313, P < 0.001] as independently associated with the development of PNA. Bilateral TT placement (OR 3.848, 95% CI: 1.219-12.143, P = 0.0216) and injury severity score (OR 1.050, 95% CI: 1.001-1.102, P = 0.0443) were independently associated with PNA development when a patient was intubated for eight days or less. The number of tube thoracostomies placed (OR 3.08, 95% CI: 1.03-9.18, P = 0.0439) was independently associated with the development of RH. Further research is warranted to identify modifiable risk factors to reduce the incidence of PNA and RH in patients with TT placed for traumatic injuries.