Intestinal Fatty Acid-Binding Protein as a Potential Biomarker for Gastrointestinal Complications after Complex Endovascular Aortic Surgery.

BACKGROUND: This study aimed to investigate the association between intestinal fatty acid-binding protein (I-FABP), acute gastrointestinal injury (AGI) grade, and gastrointestinal (GI) complications after fenestrated or branched endovascular aortic aneurysm repair. METHODS: A total of 17 patients undergoing endovascular aortic repair for thoracoabdominal, juxtarenal, suprarenal, or pararenal aneurysm between May 2017 and September 2018 were enrolled. Blood samples were collected preoperatively and during postoperative intensive care. The blood samples were analyzed for I-FABP with enzyme-linked immunosorbent assay. Gastrointestinal function was assessed according to the AGI grade every day during postoperative intensive care. RESULTS: Higher concentrations of I-FABP at 24 hr and 48 hr correlated to higher AGI grade on postoperative days 1, 2, and 3 (P = 0.032 and P = 0.048, P = 0.040 and P = 0.018, and P = 0.012 and P = 0.016, respectively). Patients who developed a GI complication within 90 days postoperatively had a higher overall AGI grade than those who did not develop a GI complication (P < 0.001), as well as higher concentrations of I-FABP at 48 hrs (P = 0.019). Patients developing GI dysfunction (AGI grade ≥2) had a higher frequency of complications (P = 0.009) and longer length of stay in the intensive care unit (P = 0.008). CONCLUSIONS: In patients undergoing endovascular aortic repair for complex aneurysm increased postoperative plasma I-FABP concentrations and postoperative GI dysfunction, evaluated using the AGI grade, were associated with GI complications, indicating that these measures may be useful in the postoperative management of these patients.

International registry on aortic balloon occlusion in major trauma: Partial inflation does not improve outcomes in abdominal trauma.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a method for temporary hemorrhage control used in haemodynamically unwell patients with severe bleeding. In haemodynamically unwell abdominal trauma patients, laparotomy remains the initial procedure of choice. Using REBOA in patients as a bridge to laparotomy is a novel option whose feasibility and efficacy remain unclear. We aimed to assess the clinical outcome in patients with abdominal injury who underwent both REBOA placement and laparotomy. METHODS: This is a retrospective study, including trauma patients with an isolated abdominal injury who underwent both REBOA placement and laparotomy, during the period 2011-2019. All data were collected via the Aortic Balloon Occlusion Trauma Registry database. RESULTS: One hundred and three patients were included in this study. The main mechanism of trauma was blunt injury (62.1%) and the median injury severity score (ISS) was 33 (14-74). Renal failure and multi-organ dysfunction syndrome (MODS) occurred in 15.5% and 35% of patients, respectively. Overall, 30-day mortality was 50.5%. Post balloon inflation systolic blood pressure (SBP) >80 mmHg was associated with lower 24-h mortality (p = 0.007). No differences in mortality were found among patients who underwent partial occlusion vs. total occlusion of the aorta. CONCLUSIONS: Our results support the feasibility of REBOA use in patients with isolated abdominal injury, with survival rates similar to previous reports for haemodynamically unstable abdominal trauma patients. Post-balloon inflation SBP >80 mmHg was associated with a significant reduction in 24-h mortality rates, but not 30-day mortality. Total aortic occlusion was not associated with increased mortality, MODS, and complication rates compared with partial occlusion.

A 12-year experience of endovascular repair for ruptured abdominal aortic aneurysms in all patients.

OBJECTIVE: Endovascular aneurysm repair (EVAR) has been increasingly performed for ruptured abdominal aortic aneurysms (rAAAs). However, multiple randomized trials have failed to demonstrate a survival benefit compared with open aortic surgery. During a 12-year period, 100% of patients without a history of aneurysm surgery had undergone EVAR for a rAAA at Örebro University Hospital, with no emergent open aortic surgery performed. In the present study, we evaluated the mortality and technical success during this "EVAR-only" period. METHODS: A single-center, retrospective observational study was conducted. We identified all patients who had presented to Örebro University Hospital with a rAAA between October 2009 and September 2021. Patients with isolated iliac artery, thoracic, and thoracoabdominal aortic ruptures were not included. Patients who had received previous aortic interventions (open or endovascular) and patients who had received palliative treatment instead of surgical intervention were also excluded. The patient characteristics, perioperative and postoperative data, and mortality rate were investigated. RESULTS: EVAR had been performed in 100 patients. Preoperative hemodynamic instability had been present in 54 patients (54%), and 18 (18%) had undergone aortic balloon occlusion. The aneurysm location was infrarenal in 89 patients (89%). Bifurcated stent grafts had been used in 97 patients (97%), and adjunct endovascular techniques had been used for 27 patients (27%). Of 98 patients, EVAR had been performed with the patient under local anesthesia for 62 patients (63%). Peri- and postoperative complications at 30 days had occurred in 20 of 100 patients (20%) and 22 of 79 patients (28%), respectively. The overall mortality at 30 days was 27% (27 of 100 patients), and the mortality for those with an isolated infrarenal rAAA was 24% (21 of 89 patients). The overall mortality at 1 year was 39% (39 of 100 patients) and for those with an isolated infrarenal rAAA was 37% (33 of 89 patients). The presence of preoperative hemodynamic instability and the use of ABO were statistically significantly and independently associated with increased 30-day mortality on multivariate logistic regression analysis. CONCLUSIONS: All 100 patients who had undergone surgery for a rAAA had been treated using EVAR and endovascular adjuncts, with a relatively low mortality rate, thus continuing the "EVAR-only" approach. A low proportion of rAAA patients were considered surgically unsuitable. These findings support the applicability of EVAR for the treatment of all rAAAs at suitable centers.

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.

Resuscitative Endovascular Balloon Occlusion of Aaorta Use in Nontrauma Emergency General Surgery: A Multi-institutional Experience.

BACKGROUND: The aim of this study was to determine the current utilization patterns of resuscitative endovascular balloon occlusion of aorta (REBOA) for hemorrhage control in nontrauma patients. METHODS: Data on REBOA use in nontrauma emergency general surgery patients from six centers, 2014-2019, was pooled for analysis. We performed descriptive analyses using Fisher's exact, Student's t, chi-squared, or Mann-Whitney U tests as appropriate. RESULTS: Thirty-seven patients with acute hemorrhage from nontrauma sources were identified. REBOA placement was primarily performed by trauma attendings (20/37, 54%) and vascular attendings (13/37, 35%). In seven patients (19%), balloons were positioned prophylactically but never inflated. In 24 (65%) of 37 patients, REBOA was placed in the operating room. 28/37 balloons (76%) were advanced to zone 1, 8/37 (22%) were advanced to zone 3, and there was one REBOA use in the inferior vena cava. Most common indications were gastrointestinal and peripartum bleeding. In the 30 cases of balloon inflation, 24 of 30 (80%) resulted in improved hemodynamics. Eleven of 30 patients (37%) died before discharge. One patient developed a distal embolism, but there were no reports of limb loss. Twelve patients (40% of all REBOA inflations and 63% of survivors) were discharged to home. CONCLUSIONS: REBOA has been used in a range of acutely hemorrhaging emergency general surgery patients with low rates of access-related complications. Mortality is high in this patient population and further research is needed; however, appropriate patient selection and early use may improve survival in these life-threatening cases.

Total resuscitative endovascular balloon occlusion of the aorta causes inflammatory activation and organ damage within 30 minutes of occlusion in normovolemic pigs.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) causes physiological, metabolic, end-organ and inflammatory changes that need to be addressed for better management of severely injured patients. The aim of this study was to investigate occlusion time-dependent metabolic, end-organ and inflammatory effects of total REBOA in Zone I in a normovolemic animal model. METHODS: Twenty-four pigs (25-35 kg) were randomized to total occlusion REBOA in Zone I for either 15, 30, 60 min (REBOA15, REBOA30, and REBOA60, respectively) or to a control group, followed by 3-h reperfusion. Hemodynamic variables, metabolic and inflammatory response, intraperitoneal and intrahepatic microdialysis, and plasma markers of end-organ injuries were measured during intervention and reperfusion. Intestinal histopathology was performed. RESULTS: Mean arterial pressure and cardiac output increased significantly in all REBOA groups during occlusion and blood flow in the superior mesenteric artery and urinary production subsided during intervention. Metabolic acidosis with increased intraperitoneal and intrahepatic concentrations of lactate and glycerol was most pronounced in REBOA30 and REBOA60 during reperfusion and did not normalize at the end of reperfusion in REBOA60. Inflammatory response showed a significant and persistent increase of pro- and anti-inflammatory cytokines during reperfusion in REBOA30 and was most pronounced in REBOA60. Plasma concentrations of liver, kidney, pancreatic and skeletal muscle enzymes were significantly increased at the end of reperfusion in REBOA30 and REBOA60. Significant intestinal mucosal damage was present in REBOA30 and REBOA60. CONCLUSION: Total REBOA caused severe systemic and intra-abdominal metabolic disturbances, organ damage and inflammatory activation already at 30 min of occlusion.

Results of postoperative microdialysis intraperitoneal and at the anastomosis in patients developing anastomotic leakage after rectal cancer surgery.

Introduction: Anastomotic leakage postoperatively in patients operated with rectum resection and primary anastomosis is a common and feared complication. We have studied seven patients with an anastomotic leakage after surgery and compared them with 13 patients without complications.Methods: Metabolic measurements with microdialysis were done during the first seven postoperative days, with measurements of glucose, pyruvate, lactate and glycerol. The lactate/pyruvate ratio was calculated. Measurements were performed subcutaneously, intraperitoneally and at the anastomosis. The inflammatory cytokines, IL 6 and IL 10, were measured intravenously and intraperitoneally 48 hours postoperatively.Results: Intravenous and intraperitoneal IL 6 were higher in the leakage group. Around the small intestine (intraperitoneally), we found that patients developing anastomotic leakage had higher lactate and lactate/pyruvate ratio immediately after surgery. They also showed lower glycerol levels. At the anastomosis, we found higher lactate and lactate/pyruvate ratio in anastomotic leak patients after the fourth postoperative day.Conclusions: The results indicate that a possible mechanism behind an anastomotic leakage is an impaired circulation and thus insufficient saturation to the small intestine peroperatively. This develops into an inflammation both intraperitoneally and intravenously, which, if not reversed, spread within the gastrointestinal tract .The colorectal anastomosis is the most vulnerable part of the gastrointestinal tract postoperatively and hypoxia and inflammation may occur there, and an anastomosis leakage will be the consequence.

Metabolic Response to Claudication in Peripheral Arterial Disease: A Microdialysis Pilot Study.

OBJECTIVES: This is a pilot study, and the objective of the study was to investigate the possible uses of microdialysis in the calf muscle to assess the metabolic response to intermittent claudication (IC) and in addition evaluate the simultaneous systemic inflammatory reaction. METHODS: Dialysate and venous blood sampling was performed before, during and after walking on a treadmill to maximal tolerable claudication (controls 10 min) using 1 microdialysis catheter inserted in the gastrocnemius muscle, 1 subcutaneously in the pectoral region (as a reference), and a peripheral venous catheter. RESULTS: A total of 9 participants were recruited, 6 patients with IC and 3 healthy control subjects. At baseline, patients with IC and control subjects did not differ in metabolic findings (glucose, lactate, pyruvate, and glycerol) in the gastrocnemius muscle. Subcutaneous glucose concentration was higher in control subjects. After physical exertion, gastrocnemius and subcutaneous glycerol, lactate, and pyruvate concentrations increased in patients with IC. Plasma concentrations of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), hepatocyte growth factor, and vascular endothelial growth factor were higher in IC subjects at baseline, and TNF-α, IL-6, and IL-18 increased after walking as did IL-6 and IL-1ß in control subjects. The muscle catheters did not show any signs of harm. CONCLUSIONS: Microdialysis can be used to study the ongoing metabolic response during walking and claudication. Our results suggest both an acute local and a systemic inflammatory reaction during development of claudication.

Intraperitoneal metabolic consequences of supraceliac aortic balloon occlusion in an experimental animal study using microdialysis.

BACKGROUND: To investigate the effects of supraceliac aortic balloon occlusion (ABO) and superior mesenteric artery (SMA) occlusion on abdominal visceral metabolism in an animal model using intraperitoneal microdialysis (IPM) and laser Doppler flowmetry. METHODS: A total of 9 pigs were subjected to ABO and 7 animals were subjected to SMA occlusion for 1 hour followed by 3 hours of reperfusion. Seven animals served as controls. Hemodynamic data, arterial blood samples, urinary output, and intestinal mucosal blood flow (IBF) were followed hourly. Intraperitoneal (i.p) glucose, glycerol, lactate, and pyruvate concentrations and lactate-to-pyruvate (l/p) ratio were measured using IPM. RESULTS: Compared with the baseline, ABO reduced IBF by 76% and decreased urinary output. SMA occlusion reduced IBF by 75% without affecting urinary output. ABO increased the i.p l/p ratio from 18 at baseline, peaking at 46 in early reperfusion. SMA occlusion and reperfusion tended to increase the i.p l/p ratio, peaking at 36 in early reperfusion. ABO increased the i.p glycerol concentration from 87 µM at baseline to 579 µM after 3 hours of reperfusion. SMA occlusion and reperfusion increased the i.p glycerol concentration but to a lesser degree. CONCLUSIONS: Supraceliac ABO caused severe hemodynamic, renal, and systemic metabolic disturbances compared with SMA occlusion, most likely because of the more extensive ischemia-reperfusion injury. The intra-abdominal metabolism, measured by microdialysis, was affected by both ABO and SMA occlusion but the most severe disturbances were caused by ABO. The i.p l/p ratios and the glycerol concentrations increased during ischemia and reperfusion and may serve as markers of these events and indicate anaerobic metabolism and cell damages respectively.

The effect of an endovascular Heaney maneuver to achieve total hepatic isolation on survival, hemodynamic stability, retrohepatic bleeding, and collateral flow in a porcine model.

PURPOSE: Combining resuscitative endovascular balloon occlusion of the aorta (REBOA) and the inferior vena cava (REBOVC) with open surgery is a new hybrid approach for treating retrohepatic vena caval injuries. We compared endovascular total hepatic isolation with supraceliac REBOA ± suprahepatic REBOVC and no occlusion in experimental retrohepatic vena cava bleeding regarding survival, bleeding volume, hemodynamic stability, and arterial collateral blood flow. METHODS: Twenty-five anesthetized pigs (n = 6-7/group) were randomized to REBOA; REBOA + REBOVC; REBOA + infra and suprahepatic REBOVC + portal vein occlusion (endovascular Heaney maneuver, four-balloon-occlusion, 4BO) or no occlusion. After balloon inflation, free bleeding was initiated from an open sheath in the retrohepatic vena cava. Bleeding volume, right internal thoracic artery (RITA) blood flow, hemodynamics, and arterial blood variables were measured until death or up to 90 min. RESULTS: The REBOA group had a longer median survival time (63 min) compared with the 4BO (24 min, P = 0.02) and no occlusion (30 min, P = 0.02) groups, not versus the REBOA + REBOVC group (49 min, P > 0.05). The first 15 min accumulated bleeding was comparable in all groups (P > 0.05); Thereafter, bleeding volume was higher in the REBOA group versus the 4BO group (P < 0.05), not versus the other groups. RITA blood flow and MAP were higher in the REBOA group versus the other groups after 10 min of bleeding (P < 0.05). CONCLUSIONS: Endovascular Heaney maneuver was not beneficial for survival or hemodynamic stability in this porcine model, whereas supraceliac REBOA was. Anatomical differences in thoracoabdominal collaterals between pigs and humans must be considered when interpreting these results.

Consensus on resuscitative endovascular balloon occlusion of the aorta in civilian (prehospital) trauma care: A Delphi study.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) could prevent lethal exsanguination and support cardiopulmonary resuscitation. In prehospital trauma and medical emergency settings, a small population with high mortality rates could potentially benefit from early REBOA deployment. However, its use in these situations remains highly disputed. Since publication of the first Delphi study on REBOA, in which consensus was not reached on all addressed topics, new literature has emerged. The aim of this study was to establish consensus on the use and implementation of REBOA in civilian prehospital settings for noncompressible truncal hemorrhage and out-of-hospital cardiac arrest as well as for various in-hospital settings. METHODS: A Delphi study consisting of three rounds of questionnaires was conducted based on a review of recent literature. REBOA experts with different medical specialties, backgrounds, and work environments were invited for the international panel. Consensus was reached when a minimum of 75% of panelists responded to a question and at least 75% (positive) or less than 25% (negative) of these respondents agreed on the questioned subject. RESULTS: Panel members reached consensus on potential (contra)indications, physiological thresholds for patient selection, the use of ultrasound and practical, and technical aspects for early femoral artery access and prehospital REBOA. CONCLUSION: The international expert panel agreed that REBOA can be used in civilian prehospital settings for temporary control of noncompressible truncal hemorrhage, provided that personnel are properly trained and protocols are established. For prehospital REBOA and early femoral artery access, consensus was reached on (contra)indications, physiological thresholds and practical aspects. The panel recommends the initiation of a randomized clinical trial investigating the use of prehospital REBOA for noncompressible truncal hemorrhage. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level V.

Critical systolic blood pressure threshold for endovascular aortic occlusion-A multinational analysis to determine when to place a REBOA.

BACKGROUND: Systolic blood pressure (SBP) is a potential indicator that could guide when to use a resuscitative endovascular balloon occlusion of the aorta (REBOA) in trauma patients with life-threatening injuries. This study aims to determine the optimal SBP threshold for REBOA placement by analyzing the association between SBP pre-REBOA and 24-hour mortality in severely injured hemodynamically unstable trauma patients. METHODS: We performed a pooled analysis of the aortic balloon occlusion (ABO) trauma and AORTA registries. These databases record the details related to the use of REBOA and include data from 14 countries worldwide. We included patients who had suffered penetrating and/or blunt trauma. Patients who arrived at the hospital with a SBP pre-REBOA of 0 mm Hg and remained at 0 mm Hg after balloon inflation were excluded. We evaluated the impact that SBP pre-REBOA had on the probability of death in the first 24 hours. RESULTS: A total of 1,107 patients underwent endovascular aortic occlusion, of these, 848 met inclusion criteria. The median age was 44 years (interquartile range [IQR], 27-59 years) and 643 (76%) were male. The median injury severity score was 34 (IQR, 25-45). The median SBP pre-REBOA was 65 mm Hg (IQR, 49-88 mm Hg). Mortality at 24 hours was reported in 279 (32%) patients. Math modeling shows that predicted probabilities of the primary outcome increased steadily in SBP pre-REBOA below 100 mm Hg. Multivariable mixed-effects analysis shows that when SBP pre-REBOA was lower than 60 mm Hg, the risk of death was more than 50% (relative risk, 1.5; 95% confidence interval, 1.17-1.92; p = 0.001). DISCUSSION: In patients who do not respond to initial resuscitation, the use of REBOA in SBPs between 60 mm Hg and 80 mm Hg may be a useful tool in resuscitation efforts before further decompensation or complete cardiovascular collapse. The findings from our study are clinically important as a first step in identifying candidates for REBOA. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

NO-Donation Increases Visceral Circulation in a Porcine Model of Abdominal Hypertension.

Intraabdominal hypertension (IAH) is negative for outcome after intensive care. Little research has focused on medical intervention to improve visceral circulation during IAH. A nitric oxide (NO)-donor was compared with placebo in 25 pigs; each pig was randomized into three groups: PDNO (NO-donor), Control (placebo), or Sham. IAH was induced by CO2 insufflation to 30 mmHg. Sham group had surgical preparation only. Blood gases, invasive venous and arterial blood pressure, intestinal microcirculation and superior mesenteric blood flow were measured. The PDNO group had significantly increased intestinal microcirculation compared with Controls during IAH (last hour, P = 0.009). The mean arterial pressure and abdominal perfusion pressures (APP) were decreased, and the cardiac index were increased in the PDNO group. Also, systemic and pulmonary vascular resistances were lower in the PDNO group compared with Controls. These experimental findings indicate that NO should be further explored with potential application to improve intestinal microcirculation in IAH patients.

Intra-aortic and Intra-caval Balloon Pump Devices in Experimental Non-traumatic Cardiac Arrest and Cardiopulmonary Resuscitation.

Intra-aortic balloon pump (IABP) use during CPR has been scarcely studied. Intra-caval balloon pump (ICBP) may decrease backward venous flow during CPR. Mechanical chest compressions (MCC) were initiated after 10 min of cardiac arrest in anesthetized pigs. After 5 min of MCC, IABP (n = 6) or ICBP (n = 6) was initiated. The MCC device and the IABP/ICBP had slightly different frequencies, inducing a progressive peak pressure phase shift. IABP inflation 0.15 s before MCC significantly increased mean arterial pressure (MAP) and carotid blood flow (CBF) compared to inflation 0.10 s after MCC and to MCC only. Coronary perfusion pressure significantly increased with IABP inflation 0.25 s before MCC compared to inflation at MCC. ICBP inflation before MCC significantly increased MAP and CBF compared to inflation after MCC but not compared to MCC only. This shows the potential of IABP in CPR when optimally synchronized with MCC. The effect of timing of intra-aortic balloon pump (IABP) inflation during mechanical chest compressions (MCC) on hemodynamics. Data from12 anesthetized pigs.

Emergent vessel embolization for major traumatic and non-traumatic hemorrhage: Indications, tools and outcomes.

Endovascular embolization of bleeding vessels in trauma and non-trauma patients is frequently used and is an important tool for bleeding control. It is included in the EVTM (endovascular resuscitation and trauma management) concept and its use in patients with hemodynamic instability is increasing. When the correct embolization tool is chosen, a dedicated multidisciplinary team can rapidly and effectively achieve bleeding control. In this article, we will describe the current use and possibilities for embolization of major hemorrhage (traumatic and non-traumatic) and the published data supporting these techniques as part of the EVTM concept.

A porcine study of ultrasound-guided versus fluoroscopy-guided placement of endovascular balloons in the inferior vena cava (REBOVC) and the aorta (REBOA).

Objectives: In fluoroscopy-free settings, alternative safe and quick methods for placing resuscitative endovascular balloon occlusion of the aorta (REBOA) and resuscitative endovascular balloon occlusion of the inferior vena cava (REBOVC) are needed. Ultrasound is being increasingly used to guide the placement of REBOA in the absence of fluoroscopy. Our hypothesis was that ultrasound could be used to adequately visualize the suprahepatic vena cava and guide REBOVC positioning, without significant time-delay, when compared with fluoroscopic guidance, and compared with the corresponding REBOA placement. Methods: Nine anesthetized pigs were used to compare ultrasound-guided placement of supraceliac REBOA and suprahepatic REBOVC with corresponding fluoroscopic guidance, in terms of correct placement and speed. Accuracy was controlled by fluoroscopy. Four intervention groups: (1) fluoroscopy REBOA, (2) fluoroscopy REBOVC, (3) ultrasound REBOA and (4) ultrasound REBOVC. The aim was to carry out the four interventions in all animals. Randomization was performed to either fluoroscopic or ultrasound guidance being used first. The time required to position the balloons in the supraceliac aorta or in the suprahepatic inferior vena cava was recorded and compared between the four intervention groups. Results: Ultrasound-guided REBOA and REBOVC placement was completed in eight animals, respectively. All eight had correctly positioned REBOA and REBOVC on fluoroscopic verification. Fluoroscopy-guided REBOA placement was slightly faster (median 14 s, IQR 13-17 s) than ultrasound-guided REBOA (median 22 s, IQR 21-25 s, p=0.024). The corresponding comparisons of the REBOVC groups were not statistically significant, with fluoroscopy-guided REBOVC taking 19 s, median (IQR 11-22 s) and ultrasound-guided REBOVC taking 28 s, median (IQR 20-34 s, p=0.19). Conclusion: Ultrasound adequately and quickly guide the placement of supraceliac REBOA and suprahepatic REBOVC in a porcine laboratory model, however, safety issues must be considered before use in trauma patients. Level of evidence: Prospective, experimental, animal study. Basic science study.

A randomized porcine study of hemorrhagic shock comparing end-tidal carbon dioxide targeted and proximal systolic blood pressure targeted partial resuscitative endovascular balloon occlusion of the aorta in the mitigation of metabolic injury.

BACKGROUND: The definition of partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) is not yet determined and clinical markers of the degree of occlusion, metabolic effects and end-organ injury that are clinically monitored in real time are lacking. The aim of the study was to test the hypothesis that end-tidal carbon dioxide (ETCO2) targeted pREBOA causes less metabolic disturbance compared to proximal systolic blood pressure (SBP) targeted pREBOA in a porcine model of hemorrhagic shock. MATERIALS AND METHODS: Twenty anesthetized pigs (26-35 kg) were randomized to 45 min of either ETCO2 targeted pREBOA (pREBOAETCO2, ETCO2 90-110% of values before start of occlusion, n = 10) or proximal SBP targeted pREBOA (pREBOASBP, SBP 80-100 mmHg, n = 10), during controlled grade IV hemorrhagic shock. Autotransfusion and reperfusion over 3 h followed. Hemodynamic and respiratory parameters, blood samples and jejunal specimens were analyzed. RESULTS: ETCO2 was significantly higher in the pREBOAETCO2 group during the occlusion compared to the pREBOASBP group, whereas SBP, femoral arterial mean pressure and abdominal aortic blood flow were similar. During reperfusion, arterial and mesenteric lactate, plasma creatinine and plasma troponin concentrations were higher in the pREBOASBP group. CONCLUSIONS: In a porcine model of hemorrhagic shock, ETCO2 targeted pREBOA caused less metabolic disturbance and end-organ damage compared to proximal SBP targeted pREBOA, with no disadvantageous hemodynamic impact. End-tidal CO2 should be investigated in clinical studies as a complementary clinical tool for mitigating ischemic-reperfusion injury when using pREBOA.

Low profile REBOA device for increasing systolic blood pressure in hemodynamic instability: single-center 4-year experience of use of ER-REBOA.

BACKGROUND: Hemodynamic instability due to torso hemorrhage can be managed with the assistance of resuscitative endovascular balloon occlusion of the aorta (REBOA). This is a report of a single-center experience using the ER-REBOA™ catheter for traumatic and non-traumatic cases as an adjunct to hemorrhage control and as part of the EndoVascular resuscitation and Trauma Management (EVTM) concept. The objective of this report is to describe the clinical usage, technical success, results, complications and outcomes of the ER-REBOA™ catheter at Örebro University hospital, a middle-sized university hospital in Europe. METHODS: Data concerning patients receiving the ER-REBOA™ catheter for any type of hemorrhagic shock and hemodynamic instability at Örebro University hospital in Sweden were collected prospectively from October 2015 to May 2020. RESULTS: A total of 24 patients received the ER-REBOA™ catheter (with the intention to use) for traumatic and non-traumatic hemodynamic control; it was used in 22 patients. REBOA was performed or supervised by vascular surgeons using 7-8 Fr sheaths with an anatomic landmark or ultrasound guidance. Systolic blood pressure (SBP) increased significantly from 50 mmHg (0-63) to 95 mmHg (70-121) post REBOA. In this cohort, distal embolization and balloon rupture due to atherosclerosis were reported in one patient and two patients developed renal failure. There were no cases of balloon migration. Overall 30-day survival was 59%, with 45% for trauma patients and 73% for non-traumatic patients. Responders to REBOA had a significantly lower rate of mortality at both 24 h and 30 days. CONCLUSIONS: Our clinical data and experience show that the ER-REBOA™ catheter can be used for control of hemodynamic instability and to significantly increase SBP in both traumatic and non-traumatic cases, with relatively few complications. Responders to REBOA have a significantly lower rate of mortality.

Hemodynamic Effect of Resuscitative Endovascular Balloon Occlusion of the Aorta in Hemodynamic Instability Secondary to Acute Cardiac Tamponade in a Porcine Model.

BACKGROUND: The pre-hospital use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is increasing, although it remains controversial, in part because of suggested contraindications such as acute cardiac tamponade (ACT). As both the pre-hospital and in-hospital use of REBOA might potentially occur with concurrent ACT, knowledge of the hemodynamic effect of REBOA in this setting is crucial. This study, therefore, aimed at investigating the physiological effects of REBOA in hemodynamic instability secondary to ACT in a porcine model. We hypothesize that REBOA can temporarily increase systemic blood pressure and carotid blood flow, and prolong survival, in hemodynamic shock caused by ACT. METHODS: Fourteen pigs (24-38 kg) underwent ACT, through true cardiac injury and hemorrhage into the pericardial space, and were allowed to hemodynamically deteriorate. At a systolic blood pressure (SBP) of 50 mm Hg (SBP50) they were randomized to total occlusion REBOA in zone 1 or to a control group. Survival, hemodynamic parameters, carotid blood flow (CBF), femoral blood flow (FBF), cardiac output (CO), end-tidal CO2, and arterial blood gas parameters were analyzed. RESULTS: REBOA intervention was associated with a significant increase in SBP (50 mm Hg to 74 mm Hg, P = 0.016) and CBF (110 mL/min to 195 mL/min, P = 0.031), with no change in CO, compared to the control group. At 20 min after SBP50, the survival rate in the intervention group was 86% and in the control group 14%, with time to death being significantly longer in the intervention group. CONCLUSIONS: This randomized animal study demonstrates that REBOA can help provide hemodynamic stabilization and prolong survival in hemodynamic shock provoked by ACT. It is important to stress that our study does not change the fact that urgent pericardiocentesis or cardiac surgery is, and should remain, the standard optimal treatment for ACT.Level of evidence: Prospective, randomized, experimental animal study. Basic science study, therapeutic.