Vascular complications secondary to resuscitative endovascular balloon occlusion of the aorta placement at a Level 1 Trauma Center.

OBJECTIVE: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is designed to manage severe hemorrhagic shock. Popularized in medical care during military conflicts, the concept has emerged as a lifesaving technique that is utilized around the United States. Literature on risks of REBOA placement, especially vascular injuries, are not well-reported. Our goal was to assess the incidence of vascular injury from REBOA placement and the risk factors associated with injury and death among these patients at our institution. METHODS: We performed a retrospective cohort study of all patients who underwent REBOA placement between September 2017 and June 2022 at our Level 1 Trauma Center. The primary outcome variable was the presence of an injury related to REBOA insertion or use. Secondary outcomes studied were limb loss, the need for dialysis, and mortality. Data were analyzed using descriptive statistics, χ2, and t-tests as appropriate for the variable type. RESULTS: We identified 99 patients who underwent REBOA placement during the study period. The mean age of patients was 43.1 ± 17.2 years, and 67.7% (67/99) were males. The majority of injuries were from blunt trauma (79.8%; 79/99). Twelve of the patients (12.1%; 12/99) had a vascular injury related to REBOA placement. All but one required intervention. The complications included local vessel injury (58.3%; 7/12), distal embolization (16.7%; 2/12), excessive bleeding requiring vascular consult (8.3%; 1/12), pseudoaneurysm requiring intervention (8.3%; 1/12), and one incident of inability to remove the REBOA device (8.3%; 1/12). The repairs were performed by vascular surgery (75%; 9/12), interventional radiology (16.7%; 2/12), and trauma surgery (8.3%; 1/12). There was no association of age, gender, race, and blunt vs penetrating injury to REBOA-related complications. Mortality in this patient population was high (40.4%), but there was no association with REBOA-related complications. Ipsilateral limb loss occurred in two patients with REBOA-related injuries, but both were due to their injuries and not to REBOA-related ischemia. CONCLUSIONS: Although vascular complications are not unusual in REBOA placement, there does not appear to be an association with limb loss, dialysis, or mortality if they are addressed promptly. Close coordination between vascular surgeons and trauma surgeons is essential in patients undergoing REBOA placement.

Intra-stent aortic wall aneurysm formation after Be-graft covered stent implant.

Aortic wall injuries may occur after interventional treatment of aortic coarctation (CoA), especially after balloon angioplasty. We reported on a patient who presented with an intra-stent aneurysm formation after direct stenting of a native near atretic aortic CoA by using a BeGraft Aortic stent. This evidence supports the need to maintain a strict follow-up protocol. A computed tomography scan is mandatory, after covered stent implantation as well, especially in high-risk cases and even in the absence of any immediate apparent complication.

Systematic Review and Meta-Analysis of Nonoperative Management for SVS Grade II Blunt Traumatic Aortic Injury.

BACKGROUND: Society for Vascular Surgery (SVS) grade II blunt traumatic aortic injury is defined as intramural hematoma with or without external contour abnormality. It is uncertain whether this aortic injury pattern should be treated with endovascular stent-grafting or nonoperative measures. Since the adoption of the SVS Guidelines on endovascular repair of blunt traumatic aortic injury, the practice pattern for management of grade II injuries has been heterogenous. The objective of the study was to report natural history outcomes of grade II blunt traumatic aortic injury. METHODS: A systematic review of published traumatic aortic injury studies was performed. Online database searches were current to November 2022. Eligible studies included data on aortic injuries that were both managed nonoperatively and classified according to the SVS 2011 Guidelines. Data points on all-cause mortality, aorta-related mortality and early aortic intervention were extracted and underwent meta-analysis. The methodology was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. RESULTS: Thirteen studies were included in the final analysis with a total of 204 cases of SVS grade II blunt traumatic aortic injury treated nonoperatively. The outcomes rates were estimated at 10.4% (95% confidence interval [CI] 6.7%-14.9%) for all-cause mortality, 2.9% (95% CI 1.1%-5.7%) for aorta-related mortality, and 3.3% (95% CI 1.4%-6.2%) for early aortic intervention. The studies included in the analysis were of fair quality with a mean Downs and Black score 15 (±1.8). CONCLUSIONS: Grade II blunt traumatic aortic injury follows a relatively benign course with few instances of aortic-related mortality. Death in the setting of this injury pattern is more often attributable to sequelae of multisystem trauma and not directly related to aortic injury. The current data support nonoperative management and imaging surveillance for grade II blunt traumatic aortic injury instead of endovascular repair. Longer-term effects on the aorta at the site of injury are unknown.

Resuscitative Endovascular Balloon Occlusion of The Aorta (REBOA) And Mortality in Hemorrhagic Shock Associated with Severe Pelvic Fracture: a National Data Analysis.

BACKGROUND: The purpose of the study was to evaluate the mortality of patients who received Resuscitative Endovascular Balloon Occlusion of The Aorta (REBOA) in severe pelvic fracture with hemorrhagic shock. METHODS: The American College of Surgeon Trauma Quality Improvement Program (ACS-TQIP) database for the calendar years 2017-2019 was accessed for the study. The study included all patients aged 15 years and older who sustained severe pelvic fractures, defined as an injury with an abbreviated injury scale (AIS) score of ≥ 3, and who presented with the lowest systolic blood pressure (SBP) of < 90 mmHg. Patients with severe brain injury were excluded from the study. Propensity score matching was used to compare the patients who received REBOA with similar characteristics to patients who did not receive REBOA. RESULTS: Out of 3,186 patients who qualified for the study, 35(1.1%) patients received REBOA for an ongoing hemorrhagic shock with severe pelvic fracture. The propensity matching created 35 pairs of patients. The pair-matched analysis showed no significant differences between the group who received REBOA and the group that did not receive REBOA regarding patients' demography, injury severity, severity of pelvic fractures, lowest blood pressure at initial assessment and laparotomies. There was no significant difference found between REBOA versus no REBOA group in overall in-hospital mortality (34.3% vs. 28.6, P = 0.789). CONCLUSION: Our study did not identify any mortality advantage in patients who received REBOA in hemorrhagic shock associated with severe pelvic fracture compared to a similar cohort of patients who did not receive REBOA. A larger sample size prospective study is needed to validate our results. CASE-CONTROL RETROSPECTIVE STUDY: Level of Evidence IV.

Early Versus Delayed Thoracic Endovascular Aortic Repair for Blunt Thoracic Aortic Injury: A Propensity Score-Matched Analysis.

OBJECTIVE: We examined early (≤24 h) versus delayed (>24 h) thoracic endovascular aortic repair (TEVAR) for blunt thoracic aortic injury (BTAI), taking the aortic injury severity into consideration. BACKGROUND: Current trauma surgery guidelines recommend delayed TEVAR following BTAI. However, this recommendation was based on small studies, and specifics regarding recommendation strategies based on aortic injury grades are lacking. METHODS: Patients undergoing TEVAR for BTAI in the American College of Surgeons Trauma Quality Improvement Program between 2016 and 2019 were included and then stratified into 2 groups (early: ≤24 h vs. delayed: >24 h). In-hospital outcomes were compared after creating 1:1 propensity score-matched cohorts, matching for demographics, comorbidities, concomitant injuries, additional procedures, and aortic injury severity based on the acute aortic syndrome (AAS) classification. RESULTS: Overall, 1339 patients were included, of whom 1054(79%) underwent early TEVAR. Compared with the delayed group, the early group had significantly less severe head injuries (early vs delayed; 25% vs 32%; P =0.014), fewer early interventions for AAS grade 1 occurred, and AAS grade 3 aortic injuries often were intervened upon within 24 hours (grade 1: 28% vs 47%; grade 3: 49% vs 23%; P <0.001). After matching, the final sample included 548 matched patients. Compared with the delayed group, the early group had a significantly higher in-hospital mortality (8.8% vs 4.4%, relative risk: 2.2, 95% CI: 1.1-4.4; P =0.028), alongside a shorter length of hospital stay (5.0 vs 10 days; P =0.028), a shorter intensive care unit length of stay (4.0 vs 11 days; P <0.001) and fewer days on the ventilator (4.0 vs 6.5 days; P =0.036). Furthermore, regardless of the higher risk of acute kidney injury in the delayed group (3.3% vs 7.7%, relative risk: 0.43, 95% CI: 0.20-0.92; P =0.029), no other differences in in-hospital complications were observed between the early and delayed group. CONCLUSION: In this propensity score-matched analysis, delayed TEVAR was associated with lower mortality risk, even after adjusting for aortic injury grade.

Quantitative study of aortic strain injuries originating from traffic accidents.

Aortic injuries are the second leading cause of death after head injuries due to traffic accidents, and strain-induced injuries are becoming increasingly prominent. The quantitative study of aortic strain injury allows for a rapid assessment of the degree of aortic injury after an accident and timely diagnosis of the pathology of aortic injury. It is more reliable than diagnosis based on clinical symptoms alone and it is faster than diagnosis based on imaging. Based on the porcine aortic tensile and injury tests, this study obtained the maximum stress threshold of the aorta that can withstand tensile stress and the safe stress threshold under tensile action, which provides a more detailed data reference about aortic injury in the field of internal medicine. Injuries to the aorta under various degrees of traction were analyzed in detail. A comprehensive and quantitative evaluation criterion for aortic strain injury was proposed, which provides a more in-depth reference for the mechanism of aortic strain injury. In addition, combining it with current imaging promises a combination of numbers and shapes for rapid and accurate diagnosis of aortic strain injury.

Control of mitochondrial function and cell growth by the atypical cadherin Fat1.

Mitochondrial products such as ATP, reactive oxygen species, and aspartate are key regulators of cellular metabolism and growth. Abnormal mitochondrial function compromises integrated growth-related processes such as development and tissue repair, as well as homeostatic mechanisms that counteract ageing and neurodegeneration, cardiovascular disease, and cancer. Physiologic mechanisms that control mitochondrial activity in such settings remain incompletely understood. Here we show that the atypical Fat1 cadherin acts as a molecular 'brake' on mitochondrial respiration that regulates vascular smooth muscle cell (SMC) proliferation after arterial injury. Fragments of Fat1 accumulate in SMC mitochondria, and the Fat1 intracellular domain interacts with multiple mitochondrial proteins, including critical factors associated with the inner mitochondrial membrane. SMCs lacking Fat1 (Fat1KO) grow faster, consume more oxygen for ATP production, and contain more aspartate. Notably, expression in Fat1KO cells of a modified Fat1 intracellular domain that localizes exclusively to mitochondria largely normalizes oxygen consumption, and the growth advantage of these cells can be suppressed by inhibition of mitochondrial respiration, which suggest that a Fat1-mediated growth control mechanism is intrinsic to mitochondria. Consistent with this idea, Fat1 species associate with multiple respiratory complexes, and Fat1 deletion both increases the activity of complexes I and II and promotes the formation of complex-I-containing supercomplexes. In vivo, Fat1 is expressed in injured human and mouse arteries, and inactivation of SMC Fat1 in mice potentiates the response to vascular damage, with markedly increased medial hyperplasia and neointimal growth, and evidence of higher SMC mitochondrial respiration. These studies suggest that Fat1 controls mitochondrial activity to restrain cell growth during the reparative, proliferative state induced by vascular injury. Given recent reports linking Fat1 to cancer, abnormal kidney and muscle development, and neuropsychiatric disease, this Fat1 function may have importance in other settings of altered cell growth and metabolism.

Resuscitative endovascular balloon occlusion of the aorta in Canada: a context-specific position paper from the Canadian Collaborative for Urgent Care Surgery (CANUCS).

SummaryResuscitative endovascular balloon occlusion of the aorta (REBOA) is a well-described intervention for noncompressible torso hemorrhage. Several Canadian centres have included REBOA in their hemorrhagic shock protocols. However, REBOA has known complications and equipoise regarding its use persists. The Canadian Collaborative on Urgent Care Surgery (CANUCS) comprises surgeons who provide acute trauma care and leadership in Canada, with experience in REBOA implementation, use, education and research. Our goal is to provide evidence- and experience-based recommendations regarding institutional implementation of a REBOA program, including multidisciplinary educational programs, attention to device and care pathway logistics, and a robust quality assurance program. This will allow Canadian trauma centres to maximize patient benefits and minimize risks of this potentially life-saving technology.

The majority of major amputations after resuscitative endovascular balloon occlusion of the aorta are associated with preadmission trauma.

OBJECTIVE: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a potentially life-saving intervention. However, recent reports of associations with limb loss and mortality have called its safety into question. We aimed to evaluate patient and hospital characteristics associated with major amputation and in-hospital mortality among patients undergoing REBOA for trauma. METHODS: The National Trauma Data Bank (2015-2017) was queried for patients presenting to trauma centers and treated with REBOA. We included REBOA performed on hospital day 1 in patients who survived 6 or more hours from presentation. Univariable and multivariable analyses evaluated associations with major amputation and in-hospital mortality. RESULTS: A total of 316 patients underwent REBOA and survived in the acute period after presentation. Overall, mean age was 45 ± 20 years and the majority were male (73%) and White (56%). Most patients presented to level I trauma centers (72%) after blunt injuries (79%) with an average Injury Severity Score (ISS) of 31 ± 15, indicating major trauma. In 15 patients (5%), there were 18 major amputations-7 above knee and 11 below knee. A subgroup of 11 amputations were either traumatic amputations (73%) or mangled limbs requiring amputation within 24 hours (27%). Of the remaining amputations, 71% were associated with ipsilateral vascular or orthopedic lower extremity injuries of serious to severe Abbreviated Injury Scale severity. Comparing patients with amputations with those without amputations, there were no significant differences in patient demographics, comorbidities, or hospital characteristics. During hospitalization, patients requiring amputation more frequently received open peripheral vascular interventions (40% vs 10%; P = .002), underwent similar numbers of endovascular interventions (6.7% vs 4.7%; P = .5), and more often developed compartment syndrome (13% vs 2%; P = .04). Overall, there were 110 deaths (35%). The major amputation prevalence was similar between patients who died vs those who survived (3.6% vs 5.3%; P = .5). In multivariable analysis, prehospital cardiac arrest (odds ratio [OR], 8.47; 95% confidence interval [CI], 1.47-48.66; P = .02), penetrating vs blunt trauma (OR, 5.5; 95% CI, 1.05-28.82; P = .04), decreased Glasgow Coma Scale score (OR, 1.18; 95% CI, 1.05-1.32; P = .01), older age (OR, 1.06; 95% CI, 1.03-1.10; P < .001), and increased Injury Severity Score (OR, 1.05; 95% CI, 1.0-1.1; P = .03) were associated with higher mortality. CONCLUSIONS: The majority of major amputations in patients undergoing REBOA were secondary to the initial traumatic mechanism. Injury type and severity, as well as initial hemodynamic derangements, are associated with mortality after REBOA. Despite concerns about prohibitive limb complications of REBOA, baseline injuries seem to be the primary cause of limb loss, but further prospective analysis is needed.

A cell permeant phosphopeptide mimetic of Niban inhibits p38 MAPK and restores endothelial function after injury.

Vascular injury leads to membrane disruption, ATP release, and endothelial dysfunction. Increases in the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) and decreases in the phosphorylation of Niban, a protein implicated in ER stress and apoptosis, are associated with vascular injury. A cell permeant phosphopeptide mimetic of Niban (NiPp) was generated. The effects of NiPp in restoring endothelial function were determined ex vivo using intact rat aortic tissue (RA) after pharmacological activation of p38 MAPK and also in multiple clinically relevant injury models. Anisomycin (Aniso) increased p38 MAPK phosphorylation and reduced endothelial-dependent relaxation in RA. Treatment with NiPp prevented Ansio-induced reduction in endothelial function and increases in p38 MAPK phosphorylation. NiPp treatment also restored endothelial function after stretch injury (subfailure stretch), treatment with acidic Normal Saline (NS), and P2X7R activation with 2'(3')-O-(4-Benzoylbenzoyl)adenosine 5'-triphosphate (BzATP). Aged, diseased, human saphenous vein (HSV) remnants obtained from patients undergoing coronary bypass surgical procedures have impaired endothelial function. Treatment of these HSV segments with NiPp improved endothelial-dependent relaxation. Kinome screening experiments indicated that NiPp inhibits p38 MAPK. These data demonstrate that p38 MAPK and Niban signaling have a role in endothelial function, particularly in response to injury. Niban may represent an endogenous regulator of p38 MAPK activation. The NiPp peptide may serve as an experimental tool to further elucidate p38 MAPK regulation and as a potential therapeutic for endothelial dysfunction.

Calcified Aortic Wall Removal for Dysphagia Aortica Caused by Chronic Traumatic Aortic Pseudoaneurysm.

In this study, we report a case of a 45-year-old man with dysphagia aortica secondary to chronic traumatic aortic pseudoaneurysm of the aortic isthmus. He had been involved in a motor vehicle accident 27 years earlier. Computed tomography demonstrated a severely calcified aortic pseudoaneurysm of the aortic isthmus that compressed the esophagus extrinsically. An invasive surgical procedure involving a graft replacement and removal of the calcified aortic wall released the esophageal compression and completely improved the patient's symptoms. To the best of our knowledge, a case of dysphagia aortica caused by calcified pseudoaneurysm has never been reported.

Efficacy and Safety of Heparinization before Deployment of Endograft for Blunt Traumatic Aortic Injury in Severely Injured Patients.

BACKGROUND: The administration of unfractionated heparin (UFH) during endovascular repair of blunt traumatic aortic injury (BTAI) is controversial. The aim of the study is to report the early outcomes of patients undergoing thoracic endovascular aortic repair (TEVAR) for BTAI, and to assess the individualized intraoperative use and dose of UFH. METHODS: This is a retrospective analysis including consecutive patients treated with TEVAR for BTAI of the descending aorta between January 1st, 2005 and December 31st, 2018. Intraoperative use and doses of UFH were analyzed. Primary outcome included a reintervention because of new onset bleeding and/or thromboembolic complication and 30-day mortality. Technical success, injury severity score (ISS), timing of treatment, and neurologic deterioration were secondary outcome. RESULTS: Thirty-six patients with a mean age of 47 ± 18 years, 30 males (83%), were included. Intraoperative administration of UFH was recorded in 30/36 patients (83%) with a mean dose of 4750 ± 2180 IU. Two patients had no UFH because of extensive intracranial hemorrhage or suspected relevant liver laceration, respectively; 1 died in theatre, 1 was already anticoagulated having a mechanical aortic valve, and in 2 no information about heparin use was found. During 30 days of follow-up, 3 patients died (8%; 3/36): 1 patient with completely transected aorta died on-table and 2 on the fifth postoperative day, 1 from trauma-associated brain injury and 1 with multi organ failure. No bleeding or thromboembolic complication requiring reintervention occurred in any patient during 30 days follow-up. In 3 patients partial unintentional coverage of the left common carotid artery occurred, resulting in technical success of 89% (32/36). Mean ISS was 43 ± 15. Thirty-five patients (97%) were severely injured having an ISS ≥ 25. Twenty-nine patients (81%) were treated within 24 hr and 6 patients (17%) within 1 week. No stroke or spinal cord ischemia was observed. CONCLUSIONS: Systemic heparinization in different doses during TEVAR for BTAI can be safe with no intraoperative bleeding or thromboembolic complications in early postoperative period.

Traumatic Aortic and Celiac Pseudoaneurysm with Aortocaval Fistula Managed with Endovascular Aortic Cuff Deployment and Open Hepatic Revascularization.

We present the case of a young patient who sustained a gunshot wound to the abdomen initially treated with laparotomy and repair of small bowel, splenic vein and diaphragmatic injuries. Subsequent computed tomography (CT) performed for hemodynamic instability demonstrated a pseudoaneurysm involving the aorta and proximal celiac artery, with an associated aortocaval fistula. An attempt at transperitoneal repair of these injuries was aborted due to extensive inflammatory changes in the region encountered during exposure. Subsequently, a hybrid repair was performed. This consisted of exclusion of the aortic and celiac artery pseudoaneurysm using an endovascular aortic cuff (22 × 39 mm, Cook Medical) via infrarenal aortic access, surgical ligation of the celiac artery branches, and revascularization via bypass from the infrarenal aortic access site arteriotomy to the common hepatic artery.

Typical Retrograde Type A Dissection After Previous Type B Dissection.

BACKGROUND: Stanford type B aortic dissection (TBAD) retrograde tears to Stanford type A AD (RTAAD) have been reported only rarely, but are often fatal. Early diagnosis and timely surgery are essential. We present a typical case of RTAAD after the tip of the stent directly damaged the ascending aorta wall. CASE: A 71-year-old woman was admitted to our department for chest pain and back pain for 10 hours. She had undergone coated stent graft implantation surgery a month previously for TBAD. On first impression, we suspected the AD may have progressed or torn retrogradely. RTAAD was confirmed by computed tomography angiography, and we successfully performed open surgery. CONCLUSION: RTAAD should be suspected in patients with chest and back pain after endovascular stent repair. Prompt recognition is essential, and early surgical treatment is strongly recommended.

Rupture of the Ascending Aorta Surgical Area Detected Using Isolated Cardiopulmonary Organ Computed Tomography Angiography: An Autopsy Case Report After Cardiac Surgery.

ABSTRACT: We report cause of death after cardiac surgery using isolated cardiopulmonary organ computed tomography angiography (CTA) and a conventional autopsy. A 56-year-old man underwent aortic valve replacement and coronary artery bypass graft surgery under extracorporeal circulation. Massive bleeding occurred suddenly, and the patient died 25 days later. An autopsy revealed fibrinous exudate in the mediastinum and tight attachment of the pericardium to the heart; there were also clots and inflammatory exudate in the chest cavity. Separating the organs in the chest cavity was difficult, especially in the surgical area. We extracted the heart and lungs together and performed cardiovascular CTA and image reconstruction. Results showed spillage of the contrast agent from the anterior wall of the ascending aorta, approximately 4.5 cm from the replaced aortic valve. A histological examination confirmed that the site of contrast agent spillage was the sutured area of the ascending aorta, which was infected, necrotic, and had ruptured. Using the CTA approach for isolated cardiopulmonary organ imaging can accurately display the location of an aortic rupture, which further guides organ inspection and tissue sampling, and avoids irreversible damage to key regions. In conclusion, the approach we describe can provide evidence for determining cause of death.

Top 10 candidate aortic disease trials.

Aortic pathologies such as aneurysm, dissection and trauma are relatively common and potentially fatal diseases. Over the past two decades, we have experienced unprecedented technical and medical developments in the field. Despite this, there is a great need, and great opportunities, to further explore the area. In this review, we have identified important areas that need to be further studied and selected priority aortic disease trials. There is a pressing need to update the AAA natural history and the role for endovascular AAA repair as well as to define biomarkers and genetic risk factors as well as influence of gender for development and progression of aortic disease. A key limitation of contemporary treatment strategies of AAA is the lack of therapy directed at small AAA, to prevent AAA expansion and need for surgical repair, as well as to reduce the risk for aortic rupture. Currently, the most promising potential drug candidate to slow AAA growth is metformin, and RCTs to verify or reject this hypothesis are warranted. In addition, the role of endovascular treatment for ascending pathologies and for uncomplicated type B aortic dissection needs to be clarified.

Balloon expandable covered stents as primary therapy for hemodynamically stable traumatic aortic injuries in children.

OBJECTIVES: To expand on the limited available literature regarding the use of balloon expandable covered stents for the treatment of traumatic aortic injuries (TAI) in the pediatric population. BACKGROUND: Although endovascular grafts have largely replaced surgery for TAI repair, there are significant limitations to the use of these grafts in pediatric patients. METHODS: Multicenter, retrospective chart review of pediatric patients with TAI following blunt chest wall trauma. Procedural characteristics, follow-up, and reinterventions are described. RESULTS: Six covered stents implanted in five patients. Median patient age was 12 years (11-13 years) and median weight 50 kg (44-54 kg). Procedural success was achieved in all cases. No procedural or postprocedural complications were noted. Median follow-up time was 24 months (11-36 months). CONCLUSIONS: Balloon expandable covered stent treatment of pediatric patients with TAI is a feasible alternative to open surgical repair, and preferred over endovascular grafts due to graft size limitations and the large delivery systems.

Minimal Aortic Injury: Mechanisms, Imaging Manifestations, Natural History, and Management.

Over the last 2 decades, increased depiction of minimal aortic injury (MAI) in the evaluation of patients who have sustained trauma has mirrored the increased utilization and improved resolution of multidetector CT. MAI represents a mild form of blunt traumatic aortic injury (BTAI) that usually resolves or stabilizes with pharmacologic management. The traditional imaging manifestation of MAI is a subcentimeter round, triangular, or linear aortic filling defect attached to an aortic wall, representing a small intimal flap or thrombus consistent with grade I injury according to the Society for Vascular Surgery (SVS). Small intramural hematoma (SVS grade II injury) without external aortic contour deformity is included in the MAI spectrum in several BTAI classifications on the basis of its favorable outcome. Although higher SVS grades of injury generally call for endovascular repair, there is growing literature supporting conservative management for small pseudoaneurysms (SVS grade III) and large intimal flaps (>1 cm, unclassified by the SVS), hinting toward possible future inclusion of these entities in the MAI spectrum. Injury progression of MAI is rare, with endovascular aortic repair reserved for these patients as well as patients for whom medical treatment cannot be implemented. No consensus on the predetermined frequency and duration of multidetector CT follow-up exists, but it is common practice to perform a repeat CT examination shortly after the initial diagnosis. The authors review the evolving definition, pathophysiology, and natural history of MAI, present the primary and secondary imaging findings and diagnostic pitfalls, and discuss the current management options for MAI. Online DICOM image stacks are available for this article. ©RSNA, 2020.

Dichloroacetate prevents restenosis in preclinical animal models of vessel injury.

Despite the introduction of antiproliferative drug-eluting stents, coronary heart disease remains the leading cause of death in the United States. In-stent restenosis and bypass graft failure are characterized by excessive smooth muscle cell (SMC) proliferation and concomitant myointima formation with luminal obliteration. Here we show that during the development of myointimal hyperplasia in human arteries, SMCs show hyperpolarization of their mitochondrial membrane potential (ΔΨm) and acquire a temporary state with a high proliferative rate and resistance to apoptosis. Pyruvate dehydrogenase kinase isoform 2 (PDK2) was identified as a key regulatory protein, and its activation proved necessary for relevant myointima formation. Pharmacologic PDK2 blockade with dichloroacetate or lentiviral PDK2 knockdown prevented ΔΨm hyperpolarization, facilitated apoptosis and reduced myointima formation in injured human mammary and coronary arteries, rat aortas, rabbit iliac arteries and swine (pig) coronary arteries. In contrast to several commonly used antiproliferative drugs, dichloroacetate did not prevent vessel re-endothelialization. Targeting myointimal ΔΨm and alleviating apoptosis resistance is a novel strategy for the prevention of proliferative vascular diseases.