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.

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.

Integrating Endovascular and Operative Intervention in Trauma.

BACKGROUND: Patterns of utilization of the hybrid operating room (hybrid-OR) in trauma have not been described. The aim of this study was to describe the sequencing and integration of endovascular and operative interventions in trauma using a hybrid-OR. MATERIALS AND METHODS: This is a single-center, retrospective cohort study of trauma patients who underwent both endovascular and operative intervention (2013-2019). Patients were separated into four groups based on procedure patterns: concomitant-linked (C-L), concomitant-independent, serial-linked (S-L) and serial-independent (S-I). The groups were defined as follows: C-L - related endovascular and operative interventions in the same OR; concomitant-independent - unrelated interventions in the same OR; S-L - related interventions in separate ORs; S-I - unrelated interventions in separate ORs. Patient characteristics, procedures performed and time to angiography in each group were analyzed. RESULTS: Out of 202 patients, most procedures utilizing the hybrid-OR were for hemorrhage control (84.1%) and were performed in a C-L manner (36.1%). Patients in the C-L group were most likely to undergo lower extremity revascularization and received the most transfusions. Patients in the S-L and S-I groups were more severely injured, had greater severe abdominal injury and were more likely to undergo damage control surgery and solid organ interventions, respectively. The C-L group had the highest percentage of patients to undergo angiography within 12 h (77%, P = 0.053). CONCLUSION: The hybrid-OR is an ideal space for hemorrhage control in trauma, but there is room for improvement in the triage of patients with non-compressible torso hemorrhage. Current practice patterns prioritize the hybrid-OR for management of lower extremity injury and are not optimal. Use of the hybrid-OR could be improved by concomitant management of patients with severe abdominal injury requiring damage control surgery.

Mesenteric vascular disease: A population-based cohort study.

OBJECTIVES: Mesenteric vascular disease carries a high risk of mortality and morbidity; however, due to obscure clinical presentation, it can be under-recognized. Currently, epidemiology of mesenteric vascular disease remains poorly defined. The aim of this study is to analyze changes in Scottish mortality rates from mesenteric vascular disease overtime. METHODS: This is a retrospective, longitudinal population-based cohort study using data extracted from death certificates and Scottish Index of Multiple Deprivation. All deaths related to a vascular disorder of the intestines recorded as an underlying cause of death between 1979 and 2014 were identified using International Classification of Disease-9 or International Classification of Disease-10 code groups. Data included demographics and location of death. The residence postcodes were used to classify socio-economic status using the Scottish Index of Multiple Deprivation. RESULTS: From 2,142,921 deaths over 36 years, 14,530 (0.7%) were due to mesenteric vascular disease with a median (interquartile range) age of 77 and a 2:1 female to male gender ratio. The mean ± standard deviation age significantly increased from 72.6 ± 12.1 in 1979 to 76.8 ± 11.1 in 2014 (p < 0.001, R2 = 0.772). Males were consistently younger than females at the time of death. The two lowest Scottish Index of Multiple Deprivation categories accounted for half of the cohort, throughout the study period (p = 0.068). The adjusted death rate per 100,000 population increased from 7.6 in 1979 to 12.1 in 2014. CONCLUSIONS: The reported death rates of mesenteric vascular disease in Scotland between 1979 and 2014 have nearly doubled. Mesenteric vascular disease affects twice as many women as men and is associated with social deprivation. The increased reporting of mesenteric vascular disease is likely due to increased recognition and incidence. These implications should be considered when planning healthcare provision in Scotland.

Safety and efficacy of radial access in trauma in 65 trauma endovascular cases.

OBJECTIVE: Endovascular techniques in trauma surgery are becoming increasingly important in patient management, with procedures such as pelvic and splenic angioembolization becoming the standard of care for certain injuries. Traditionally, such interventions are performed via femoral access, although the morbidity of this approach is not insignificant (3%-10%). Transradial access (TRA) is an attractive alternative, pioneered by cardiologists, with low rates of access site complications in patients undergoing coronary intervention. Recently, this technology has extended to other interventions. The aim of this study was to present the initial experience of a radial program in a busy trauma center, with specific regard to safety and complications. METHODS: The medical records of trauma patients undergoing endovascular procedures via TRA between March 2018 and December 2018 were queried for procedural and postoperative data. Demography and injury characteristics were presented for the overall cohort, followed by a comparison of procedural data and complications between laterality. Continuous variables were compared using a two-tailed t-test and categorical variables were compared using a χ2 test. RESULTS: Over a 9-month period, 65 patients underwent 81 interventions via TRA, most commonly solid organ or pelvic angiography/embolization. Radial artery access was achieved in all patients, with procedural success achieved in all but two patients (n = 63 [96.9%]) who had hypoplastic radial artery anatomy, who underwent ulnar access. The overall technique-related complication rate was 1.5% with no difference observed between laterality (n = 1; P = .523). One patient with an admission Glasgow Coma Score of 3 and coagulopathy developed radial artery thrombosis after pelvic angiography via right TRA. Mortality was seen in seven patients (10.8%) owing to hemorrhagic shock (n = 3 [42.8%]) or multiorgan failure (n = 4 [57.1%]). There were no cases of postprocedural access site bleeding, hematoma, pseudoaneurysm, vascular injury, intraoperative arrhythmia or cerebrovascular accident, arteriovenous fistula formation, or infection. CONCLUSIONS: TRA is a feasible and low-risk alternative for endovascular intervention in the trauma patient. It yields good technical success with low morbidity. Although larger studies are needed to establish the full efficacy of TRA at the multi-institutional level, this single-institution study demonstrates the legitimacy of an alternative means for endovascular intervention in the trauma patient.

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.

The management of lower limb arteriovenous grafts in the perioperative period following renal transplantation.

BACKGROUND: The presence of a lower limb arteriovenous graft (LL-AVG) is indicative of a group of complex hemodialysis patients who have precarious long-term vascular access. The aim of this study is to describe our experience of the clinical decisions and interactions between LL-AVG and renal transplantation. METHODS: The records of 23 patients who received a transplant in the presence of a LL-AVG between 2010 and 2018 were analyzed: firstly, to determine whether patients with a LL-AVG received extended criteria transplants, the implantation procedure, and the management of the LL-AVG in the post-operative period. RESULTS: Seventeen patients (74%) had "end-stage access" and were thus considered for all offer stratified by the kidney donor profile index (KDPI) and donor type (DBD or DCD). In eleven patients (48%), a kidney with a high risk of delayed graft function was transplanted. Same-sided renal transplantation occurred in only 35% of cases, and of these, only one LL-AVG was ligated immediately to improve transplant perfusion. CONCLUSION: A patient-based approach applied in decision-making on management of the LL-AVG post-transplantation should include (a) the likelihood of delayed graft function, (b) the need for post-operative hemodialysis, (c) the side of proposed transplant compared to the LL-AVG, and (d) local complications.

A Comparison of Transradial and Transfemoral Access for Splenic Angio-Embolisation in Trauma: A Single Centre Experience.

OBJECTIVE: The study compared transradial access (TRA) and transfemoral access (TFA) for splenic angio-embolisation (SAE), with a focus on technical success, intra-operative adjuncts, and complications. METHODS: This was a retrospective comparative study of all trauma patients undergoing SAE by TRA or TFA between February 2015 and February 2019 at a single institution. The medical records were queried for procedural and post-operative data, with comparisons made based on access site. Continuous variables were compared using a two tailed t test and categorical variables were compared using a chi square test. RESULTS: Over a four year period, there were 47 cases of SAE via TRA and 127 via TFA. Technical success was 95.7% during TRA and 98.4% during TFA (p = .30). Technical failures were a result of failed splenic artery cannulation after successful radial or femoral access. Time to splenic cannulation was shorter in the TRA group (19 min vs. 30 min; p = .008). Two or fewer catheters were used during TRA, whereas more than two catheters were needed during TFA (p < .001). There were no statistically significant differences in procedure length, fluoroscopy time, radiation dose, or contrast volume between groups. Nine patients (5.2%) developed access related complications, all in the TFA group (p = .12). Mortality rate was 2.3% (n = 4), with no statistical significance between groups (p = .71). CONCLUSION: While TFA is the conventional strategy for SAE, TRA is a safe and efficacious modality for SAE in trauma patients. Although larger studies are needed to establish the full efficacy of TRA for SAE at the multi-institutional level, this single centre study demonstrates the legitimacy of an alternative means for SAE in the trauma population.

Improving the safety of resuscitative endovascular balloon occlusion of the aorta - Compliant versus semi-compliant balloon systems.

OBJECTIVES: Resuscitative endovascular balloon occlusion of the aorta is an alternative to resuscitative thoracotomy in non-compressible torso haemorrhage. Low-profile, compliant balloon catheter systems have been developed, which can be deployed without the need for fluoroscopy. However, concern exists for over inflation and aortic injury, especially as compliant balloon material can stretch reducing syringe feedback and limiting the effectiveness of a safety valve. An alternative material would be a semi-compliant balloon material, but its performance is unknown. The aim of this study was to compare the inflation characteristics of compliant versus semi-compliant balloon systems and to determine whether a pressure relief safety valve can be practically applied to a semi-compliant balloon catheter as a safety device. METHODS: This was an ex vivo study using porcine segments of thoracic aorta. The study consisted of two phases. The first phase involved intermittent inflation of six compliant balloon and six semi-compliant balloon balloons until balloon or aortic rupture. In the second phase, six semi-compliant balloons with the pressure-relief valve set at 0.45 atmospheres were inflated in the aortas until the valve release, followed by injection with additional 30 mL. Data including pressure, volume, balloon working length, diameter and circumferential stretch ratio were collected. RESULTS: At failure, mean balloon volume was almost double in compliant balloon group vs semi-compliant balloon group - 49.83 mL (±23.25) and 25.16 mL (±8.93), respectively (p = 0.004), with 36% increase in working length in the compliant balloon group - 81.17 mm (±19.11) vs 59.49 (±4.86) for semi-compliant balloon (p = 0.023). When plotted, the relationship pattern between volume and pressure fit a linear model for the compliant balloon, and a quadratic model for the semi-compliant balloon. Following attempted over inflation with the pressure valve, there was no change in parameters before and after attempted over inflation. CONCLUSIONS: The inflation profile differs between balloon designs. In contrast to semi-compliant balloons, compliant balloons will accommodate more volume to mitigate increase in pressure. This does not completely eliminate the risk of over inflation. The inflation characteristics of the semi-compliant balloon permit pairing it with a safety valve, which could lead to a development of a safer balloon technology in the future.

A Surgical Endovascular Trauma Service Increases Case Volume and Decreases Time to Hemostasis.

OBJECTIVES: The aim of this study was to evaluate the effect of a recently active endovascular trauma service (ETS) on case volume and time to hemostasis, as a complement to an existing interventional radiology (IR) service. SUMMARY BACKGROUND DATA: Endovascular techniques are vital for trauma care, but timely access can be a challenge. There is a paucity of data on the effect of a multispecialty team for delivery of endovascular hemorrhage control. METHODS: The electronic medical record of trauma patients undergoing endovascular procedures between 2013 and 2018 was queried for provider type (IR or ETS). Case volume and rates were expressed per 100 monthly admissions, normalizing for seasonal variation. Interrupted time series analysis was used to model the case rate pre- and post-introduction of the ETS. Admission-to-procedure-time data were collected for pelvic angioembolization as a marker of patients requiring emergency hemostasis. RESULTS: During 6 years, 1274 admission episodes required endovascular interventions. Overall case volume increased from 2.7 to 3.6 at a rate of 0.006 (P = 0.734) after introduction of the ETS. IR case volume decreased from 3.3 to 2.6 at a rate of 0.03 (P = 0.063). ETS case volume increased at a rate of 0.048 (P < 0.001), which was significantly different from the IR trend (P < 0.001). Median (interquartile range) time-to-procedure (hours) was significantly shorter for pelvic angioembolization [3.0 (4.4) vs 4.3 (3.6); P < 0.001] when ETS was compared to IR. CONCLUSION: A surgical ETS increases case volume and decreases time to hemostasis for trauma patients requiring time sensitive interventions. Further work is required to assess patient outcome following this change.

Viscoelastic Signals for Optimal Resuscitation in Trauma: Kaolin Thrombelastography Cutoffs for Diagnosing Hypofibrinogenemia (VISOR Study).

BACKGROUND: Acute traumatic coagulopathy is common in trauma patients. Prompt diagnosis of hypofibrinogenemia allows for early treatment with cryoprecipitate or fibrinogen concentrate. At present, optimal cutoffs for diagnosing hypofibrinogenemia with kaolin thrombelastography (TEG) have not been established. We hypothesized that kaolin kaolin-TEG parameters, such as kinetic time (K-time), α-angle, and maximum amplitude (MA), would accurately diagnose hypofibrinogenemia (fibrinogen <200 mg/dL) and severe hypofibrinogenemia (fibrinogen <100 mg/dL). METHODS: Adult trauma patients (injury severity score >15) presenting to our trauma center between October 2015 and October 2017 were identified retrospectively. All patients had a traditional plasma fibrinogen measurement and kaolin-TEG performed within 15 minutes of each other and within 1 hour of admission. Some patients had additional measurements after. Receiver operating characteristic (ROC) curve analysis was performed to evaluate whether K-time, α-angle, and MA could diagnose hypofibrinogenemia and severe hypofibrinogenemia. Area under the ROC curve (AUROC) was calculated for each TEG parameter with a bootstrapped 99% confidence interval (CI). Further, ROC analysis was used to estimate ideal cutoffs for diagnosing hypofibrinogenemia and severe hypofibrinogenemia by maximizing sensitivity and specificity. In addition, likelihood ratios were also calculated for different TEG variable cutoffs to diagnose hypofibrinogenemia and severe hypofibrinogenemia. RESULTS: Seven hundred twenty-two pairs of TEGs and traditional plasma fibrinogen measurements were performed in 623 patients with 99 patients having additional pairs of tests after the first hour. MA (AUROC = 0.84) and K-time (AUROC = 0.83) better diagnosed hypofibrinogenemia than α-angle (AUROC = 0.8; P = .03 and P < .001 for AUROC comparisons, respectively). AUROCs statistically improved for each parameter when severe hypofibrinogenemia was modeled as the outcome (P < .001). No differences were found between parameters for diagnosing severe hypofibrinogenemia (P > .05 for all comparisons). The estimated optimal cutoffs for diagnosing hypofibrinogenemia were 1.5 minutes for K-time (95% CI, 1.4-1.6), 70.0° for α-angle (95% CI, 69.8-71.0), and 60.9 mm for MA (95% CI, 59.2-61.8). The estimated optimal cutoffs for diagnosing severe hypofibrinogenemia were 2.4 minutes for K-time (95% CI, 1.7-2.8), 60.6° for α-angle (95% CI, 57.2-67.3), and 51.2 mm for MA (95% CI, 49.0-56.2). Currently recommended K-time and α-angle cutoffs from the American College of Surgeons had low sensitivity for diagnosing hypofibrinogenemia (3%-29%), but sensitivity improved to 74% when using optimal cutoffs. CONCLUSIONS: Kaolin-TEG parameters can accurately diagnose hypofibrinogenemia and severe hypofibrinogenemia in trauma patients. Currently recommended cutoffs for the treatment of hypofibrinogenemia are skewed toward high specificity and low sensitivity. Many patients are likely to be undertreated for hypofibrinogenemia using current national guidelines.

Maintaining lower limb access with the HeRO device.

Central venous catheters (CVC) remain a mainstay of vascular access particularly for incident patients,but lead to central vein stenosis (CVS) in up to 1 in 6 patents. This often leads to establishing dialysis access in the groin which in turn may result in development of CVS in the lower body, although this is poorly reported. The HeRO device was designed to address CVS by bypassing the stenosed veins with a nitinol-reinforced silicone tube into the right atrium, which acts as an outflow conduit attached to an arterial inflow. The efficacy and safety of the HeRO device in the upper limb is well established, but there is no data on its use in the lower limb. We describe 2 cases of HeRO in the lower limb, one primary and one secondary, which remain in use. Lower limb HeRO is feasible in the lower limb and can work well either as de novo (to achieve vascular access) or as a salvage procedure (to maintain vascular access).

Development of a Patient-Specific 3D-Printed Liver Model for Preoperative Planning.

INTRODUCTION: Liver surgery is widely used as a treatment modality for various liver pathologies. Despite significant improvement in clinical care, operative strategies, and technology over the past few decades, liver surgery is still risky, and optimal preoperative planning and anatomical assessment are necessary to minimize risks of serious complications. 3D printing technology is rapidly expanding, and whilst appliactions in medicine are growing, but its applications in liver surgery are still limited. This article describes the development of models of hepatic structures specific to a patient diagnosed with an operable hepatic malignancy. METHODS: Anatomy data were segmented and extracted from computed tomography and magnetic resonance imaging of the liver of a single patient with a resectable liver tumor. The digital data of the extracted anatomical surfaces was then edited and smoothed, resulting in a set of digital 3D models of the hepatic vein, portal vein with tumor, biliary tree with gallbladder, and hepatic artery. These were then 3D printed. RESULTS: The final models of the liver structures and tumor provided good anatomical detail and representation of the spatial relationships between the liver tumor and adjacent hepatic structures and could be easily manipulated and explored from different angles. CONCLUSIONS: A graspable, patient-specific, 3D printed model of liver structures could provide an improved understanding of the complex liver anatomy and better navigation in difficult areas and allow surgeons to anticipate anatomical issues that might arise during the operation. Further research into adequate imaging, liver-specific volumetric software, and segmentation algorithms are worth considering to optimize this application.

3D digital anatomy modelling - Practical or pretty?

BACKGROUND: With an increasing move towards digitalisation of medical records and medical teaching, such as online exams and webinars, one of the questions that persists asks 'is there a place for digital anatomy teaching and can it effectively replace the traditional teaching methods such as cadaveric dissection?' Cadaveric dissection has a number of benefits as a teaching method but it also has its limitations. Although these can be partially addressed by prosections and new more "life-like" fixatives, it does not address the lack of resources and the increasing pressure to be able to study and learn at home. METHODS: This paper reviews the literature with regards to the suitability of digital models for teaching and the wider uses a 3D digital anatomy model could have, such as postgraduate teaching, patient education and surgical planning. It also looks briefly at the learning model that anatomy as art contributes. RESULTS: The literature has scattered examples of digital models used for teaching at both undergraduate and postgraduate level, which demonstrate a number of positive outcomes, mostly surrounding user satisfaction and convenience. 3D modelling for patient education and operation planning has less exploration, and these papers generate a number of discussion points, mostly surrounding the practicality of digital models, which can be more time consuming and require the technology to be widely available and reliable. CONCLUSIONS: 3D digital anatomy is a useful adjunct to teaching and its use in patient education and operation planning have interesting possibilities still to be fully explored.

From cadavers to clinical practice: the anatomy of lifelong learning.

BACKGROUND: Much has been postulated about the perceived deterioration of anatomy knowledge amongst graduates. Little is known about levels of confidence in, and educational needs concerning, clinical anatomy knowledge amongst foundation year doctors. AIMS: To establish foundation year doctors' perceptions of anatomy related to: importance to career, confidence in anatomy knowledge and its application, preferred methods of teaching. Secondarily, to determine impact of an integrated clinical approach to anatomy teaching on foundation year doctors' level of knowledge and confidence in its clinical application of anatomy. METHODS: A course teaching anatomy through common surgeries and related radiology was delivered to foundation year doctors. A pre- and post-course assessment based on anatomy competence score assessed holistic knowledge acquisition. Foundation year doctors' perceptions of anatomy and course satisfaction were measured through questionnaire. RESULTS: Confidence in applying anatomy knowledge was low. The average pre- and post-course assessment score increased from 55% to 81%; 92.86% felt an integrated clinical approach to anatomy teaching improved their confidence on the subject and 58.62% felt it improved their clinical skills. CONCLUSION: This study identified a need for ongoing educational support for foundation year doctors regarding anatomy teaching. An integrated clinical approach to teaching anatomy proved both highly relevant and popular, as well as an effective teaching approach.

Type II endoleak accompanied by an arteriovenous fistula between the inferior mesenteric artery and the inferior vena cava as a complication of endovascular aneurysm repair.

Endovascular aneurysm repair (EVAR) has become one of the most important treatments for aortic abdominal aneurysm. This method has some possible complications, including a type II endoleak (T2E). When coexisting with arteriovenous fistulas (AVF), T2E can lead to serious hemodynamic consequences and organ failure. This report describes the management of a patient with T2E coexisting with AVF following an EVAR and re-EVAR procedure. Although T2E itself may be treated with a conservative approach in some cases, in the presented patient an operative approach was necessary because of coexisting AVF. In addition, due to unusual hemodynamic conditions created by concomitant ACF and T2E, fistula closure was obtained as a result of transarterial inferior mesenteric artery embolization. Post-EVAR imaging, including ultrasound and computed tomography angiography, has proven to be essential when caring for these patients.

Class of hemorrhagic shock is associated with progressive diastolic coronary flow reversal and diminished left ventricular function.

Introduction: The relationship between coronary artery flow and left ventricular (LV) function during hemorrhagic shock remains unknown. The aim of this study was to quantify coronary artery flow directionality alongside left ventricular function through the four classes of hemorrhage shock. Methods: Following baseline data collection, swine were exsanguinated into cardiac arrest via the femoral artery using a logarithmic bleed, taking each animal through the four classes of hemorrhagic shock based on percent bleed (class I: 15%; class II: 15%-30%; class III: 30%-40%; class IV: >40%). Telemetry data, left ventricular pressure-volume loops, and left anterior descending artery flow tracings over numerous cardiac cycles were collected and analyzed for each animal throughout. Results: Five male swine (mean 72 ± 12 kg) were successfully exsanguinated into cardiac arrest. Mean left ventricular end-diastolic volume, end-diastolic pressure, and stroke work decreased as the hemorrhagic shock class progressed (p < 0.001). The proportion of diastole spent with retrograde coronary flow was also associated with class of hemorrhagic shock (mean 5.6% of diastole in baseline, to 63.9% of diastole in class IV; p < 0.0001), worsening at each class from baseline through class IV. Preload recruitable stroke work (PRSW) decreased significantly in classes II through IV (p < 0.001). Systemic Vascular Resistance (SVR) is associated with class of hemorrhage shock (p < 0.001). Conclusion: With progressive classes of hemorrhagic shock left ventricular function progressively decreased, and the coronary arteries spent a greater proportion of diastole in retrograde flow, with progressively more negative total coronary flow. Preload recruitable stroke work, a load-independent measure of inotropy, also worsened in severe hemorrhagic shock, indicating the mechanism extends beyond the drop in preload and afterload alone.