Utility of motor-evoked potentials in contemporary open thoracoabdominal aortic repair.

OBJECTIVE: Paraplegia remains one of the major complications of contemporary open thoracoabdominal aortic aneurysm (TAAA) repair. Intraoperative motor-evoked potentials (MEPs) act as a surrogate measure for spinal cord homeostasis. The purpose of this study was to evaluate the results of intraoperative neuromonitoring in contemporary TAAA repair and its association with postoperative spinal cord ischemia (SCI). METHODS: Patients who underwent open type 2 or 3 TAAA or completion aortic repair using intraoperative neuromonitoring were identified between May 2006 and November 2023. Patient demographics, comorbidities, indication for the procedure, procedural details, and outcomes were recorded. The groups were divided based on type of repair, and univariate statistics were then used to evaluate the association of these metrics vs the type of repair. RESULTS: Seventy-nine patients underwent open type 2 (N = 41) and 3 (N = 23) TAAA and completion aortic (N = 15; open in 14 and endovascular in 1) repairs by a single surgeon. The cohort was predominantly male (N = 48, 60.8%) with a mean age of 52.5 ± 16.2 years. There was a high incidence of hypertension (N = 53, 67.1%), smoking history (N = 42, 53.1%), and connective tissue disorders (N = 37, 46.8%). Operative indications included dissection-related (N = 50, 63.3%) and degenerative (N = 26, 32.9%) TAAA and dissection-related malperfusion (N = 3, 3.8%). Left heart bypass was often (N = 73, 92.4%) used for distal aortic perfusion, and cerebrospinal fluid drainage (N = 77, 97.5%) was a common adjunct. MEPs were classified as no change (N = 43, 54.4%), reversible change (N = 26, 32.9%), irreversible change (N = 4, 5.1%), and unreliable (N = 6, 7.6%). MEP changes were predominantly bilateral (N = 70, 88.6%) and occurred most often during repair of the abdominal aortic segment (N = 13, 16.5%). The median number of replaced vertebral levels was associated with MEP changes (P = .013). SCI was only observed in repairs greater than 6 replaced vertebral levels with an overall frequency of 17.7%. It was most prevalent in completion aortic repairs (26.7%). Immediate and delayed SCI occurred in 10.1% and 7.6% of patients, respectively; it was most commonly (71.8%) reversible. Permanent paraplegia occurred in four patients (5.1%), with equal immediate and delayed onsets. MEPs demonstrated poor sensitivity (53.9%) and specificity (62.3%) for SCI; however, there was a high negative predictive value (86.4%) in this population. In-hospital mortality occurred in five (6.3%) patients. CONCLUSIONS: No changes in intraoperative MEPs are highly predictive of spinal cord homeostasis. The number of replaced vertebral levels and previous aortic repair should guide intraoperative neuroprotective measures including intercostal reimplantation and should take precedence over intraoperative monitoring, especially when MEP changes occur.

Raising Systemic Blood Pressure to Delay Irreversible Intestinal Ischemia in a Swine Model of Proximal Superior Mesenteric ArteryOcclusion.

INTRODUCTION: Acute proximal superior mesenteric artery (SMA) occlusion is highly lethal, and adjuncts are needed to mitigate ischemic injury until definitive therapy. We hypothesized that raising mean arterial pressure (MAP) >90 mmHg with norepinephrine may delay irreversible bowel ischemia by increasing gastroduodenal artery (GDA) flow despite possible pressor-induced vasospasm. METHODS: 12 anesthetized swine underwent laparotomy, GDA flow probe placement, and proximal SMA exposure and clamping. Animals were randomized between conventional therapy (CT) versus targeted MAP >90 mmHg (MAP push; MP) where norepinephrine was titrated after 45 min of SMA occlusion. Animals were followed until bowel death or 4 h. Kaplan-Meier bowel survival, mean normalized GDA flow, and histology were compared. RESULTS: 12 swine (mean 57.8 ± 7.6 kgs) were included, six per group. Baseline weight, HR, MAP and GDA flows were not different. Within 5 min following SMA clamping, all 12 animals had an increase in MAP without other intervention from 81.7 to 105.5 mmHg (29.1%, P < 0.01) with a concomitant 74.9% increase in GDA flow as compared to baseline (P < 0.01). Beyond 45 min postclamp, MAP was greater in the MP group as intended, as were GDA flows. Median time to irreversibly ischemic bowel was 31% longer for MAP push animals (CT: 178 versus MP: 233 min, P = 0.006), Hazard Ratio of CT 8.85 (95% CI: 1.86-42.06); 3/6 MP animals versus 0/6 CT animals with bowel survived to predetermined end point. CONCLUSIONS: In this swine model of acute complete proximal SMA occlusion, increasing MAP >90 mmHg with norepinephrine was associated with an increase in macrovascular blood flow through the GDA and bowel survival. Norepinephrine was not associated with worse bowel survival and a MAP push may increase the time window where ischemic bowel can be salvaged.

Females are less likely to receive best medical therapy for stroke prevention before and after carotid revascularization than males.

BACKGROUND: Current professional guidelines recommend best medical therapy (BMT) with statin agents and antiplatelet therapy for primary and secondary stroke prevention in patients with carotid artery stenosis. We aimed to assess the association of patient sex with preoperative BMT in patients undergoing carotid revascularization. METHODS: We performed a retrospective review of Vascular Quality Initiative patients who underwent carotid endarterectomy or carotid artery stenting between January 2003 and February 2022. Multivariable logistic regression models were used to assess the association of patient sex with preoperative BMT after adjusting for sociodemographic, comorbidity, and disease severity characteristics. In-hospital outcomes were assessed by sex and preoperative BMT status. RESULTS: Of 214,008 patients who underwent carotid revascularization, 38.7% (n = 82,855) were female and 61.3% (n = 131,153) were male. Overall, 77.2% (n = 63,922) of females were on preoperative BMT, compared with 80.4% (n = 105,375) of males (P < .001). After adjusting for baseline differences, females had 11% lower odds of being on BMT compared with males (adjusted odds ratio, 0.89; 95% confidence interval, 0.86-0.91). Postoperatively, females had 18% lower odds of being prescribed BMT than males (adjusted odds ratio, 0.82; 95% confidence interval, 0.79-0.84). In-hospital stroke (1.20% vs 1.51%), death (0.37% vs 0.66%), and stroke/death (1.46% vs 1.98%) were all significantly lower for patients on BMT (all P < .001). CONCLUSIONS: There is a significant discrepancy in the proportion of females versus males receiving preoperative BMT for stroke prevention before carotid artery revascularization. In-hospital outcomes are worse in patients without BMT, highlighting the importance of raising awareness and implementing targeted interventions to improve preoperative adherence to stroke prevention guidelines.

Practice patterns surrounding the use of tibial interventions for claudication in the Medicare population.

OBJECTIVE: At present, no data are available to support the use of tibial interventions in the treatment of claudication. We characterized the practice patterns surrounding tibial peripheral vascular interventions (PVIs) for patients with claudication in the United States. METHODS: Using 100% Medicare fee-for-service claims from 2017 to 2019, we conducted a retrospective analysis of all patients who underwent an index PVI for claudication. Patients with any previous PVI, acute limb ischemia, or chronic limb-threatening ischemia in the preceding 12 months were excluded. The primary outcome was the receipt or delivery of tibial revascularization during an index PVI for claudication, defined as tibial PVI with or without concomitant femoropopliteal PVI. Univariable comparisons and multivariable hierarchical logistic regression were used to assess the patient and physician characteristics associated with the use of tibial PVI for claudication. RESULTS: Of 59,930 Medicare patients who underwent an index PVI for claudication between 2017 and 2019, 16,594 (27.7%) underwent a tibial PVI (isolated tibial PVI, 38.5%; tibial PVI with concomitant femoropopliteal PVI, 61.5%). Of the 1542 physicians included in our analysis, the median physician-level tibial PVI rate was 20.0% (interquartile range, 9.1%-37.5%). Hierarchical logistic regression suggested that patient-level characteristics associated with tibial PVI for claudication included male sex (adjusted odds ratio [aOR], 1.23), increasing age (aOR, 1.30-1.96), Black race (aOR, 1.47), Hispanic ethnicity (aOR, 1.86), diabetes (aOR, 1.36), no history of hypertension (aOR, 1.12), and never-smoking status (aOR, 1.64; P < .05 for all). Physician-level characteristics associated with tibial PVI for claudication included early-career status (aOR, 2.97), practice location in the West (aOR, 1.75), high-volume PVI practice (aOR, 1.87), majority of practice in an ambulatory surgery center or office-based laboratory setting (aOR, 2.37), and physician specialty. The odds of vascular surgeons performing tibial PVI were significantly lower compared with radiologists (aOR, 2.98) and cardiologists (aOR, 1.67; P < .05 for all). The average Medicare reimbursement per patient was dramatically higher for physicians performing high rates of tibial PVI (quartile 4 vs quartile 1-3, $12,023.96 vs $692.31 per patient; P < .001). CONCLUSIONS: Tibial PVI for claudication was performed more often by nonvascular surgeons in high-volume practices and high-reimbursement settings. Thus, a critical need exists to reevaluate the indications, education, and reimbursement policies surrounding these procedures.

A Novel Sutureless Anastomotic Device in a Swine Model: A Proof of Concept Study.

INTRODUCTION: Vascular reconstruction requires technical expertise and is often time consuming. As a novel alternative to traditional hand-sewn vascular anastomoses, the VasoLock (VL), is a nonabsorbable, sutureless anastomosis device with traction anchors designed to hold free artery ends together. These anchors do not penetrate the vessel wall but adhere by leveraging the elasticity of the vessels to fasten blood vessels together. This pilot study assesses the performance and patency of this novel device in a porcine model of femoral artery injury. METHODS: Female swine (n = 7) underwent femoral artery exposure for a total of 10 VL implanted. Study animals underwent hemodilution to a target hematocrit of 15% and ROTEM was used to assess coagulopathy, followed by an arterial injury via transection. The VL was inserted without any sutures. Flow-probe monitors were positioned proximal and distal to the device and flow rates were measured continuously for a total of 90 min. Flow was analyzed and presented as a ratio of distal to proximal flow with the slope of this ratio across time subsequently determined. Angiographic assessment was completed to evaluate for patency and technical complications after 90 min of implant. RESULTS: The average animal weight was 44.1 ± 3.2 kg. The average mean arterial pressure at the time of implant was 51.2 ± 7.8 mmHg, median heart rate was 77.4 (IQR = 77.25-157.4) beats per minute, and average temperature was 36.1 ± 1.5°C. The baseline hematocrit was 13.5 ± 3.0%, average pH was 7.20 ± 0.1, average clotting time was 154.1 ± 58.7 s and average clot formation time was 103.4 ± 10.9 s all demonstrating the acidotic, hypothermic, and coagulopathic state of the swine at the time of insertion. During the 90-min observation period, the average flow gradient identified across the VL was 0.99 ± 0.24, indicating no significant change in flow across the VL. The average slope of the gradients was 0.0005 (P = 0.22), suggesting the ratio of proximal and distal flow did not change over the 90 min. Following 90 min of dwell time, all VL were patent without technical complication. Angiographic assessment at 90 min demonstrated no evidence of dissection, device migration, arterial extravasation, or thromboembolism with any of the 10 devices. CONCLUSIONS: This pilot study demonstrated technical feasibility of the novel VL device over a 90-min observation period. All VL were patent and no negative events or complications were identified. This technology demonstrated significant promise in a coagulopathic state: additional investigation, involving long-term survival, is warranted for further validation.

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

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

A 10-Year Analysis of Representation of Women in Patent Applications and NIH Funding in Vascular Surgery.

BACKGROUND: There has been an increasing focus on gender disparities in the medical field and in the field of vascular surgery specifically. We aimed to characterize gender representation in vascular surgery innovation over the past 10 years, using metrics of patents and National Institutes of Health (NIH) support. METHODS: We performed a retrospective review of all vascular-related patent filings (Google Scholar) and NIH-funded grants (NIH RePORTER) over a 10-year period (January 1st, 2012, to December 31st, 2021). Gender-API (Application Programming Interface) was used to identify the gender of the inventors, with manual confirmation of a 10% random sample. Gender representation for patent inventors and grant principal investigators (PIs) were compared using Chi-squared and Student's t-tests as appropriate. Yearly temporal changes in representation were analyzed using Wilcoxon signed-rank tests and linear regression analyses. RESULTS: We identified 2,992 unique vascular device patents with 6,093 associated inventors over 10 years. Women were underrepresented in patent authorship overall (11.5%), and were least likely to be listed as first inventor (8.9%) and most commonly fourth and fifth inventors (15.5% and 14.1%, respectively) compared to men. There was no significant change in representation of women inventors over time (-0.2% females per year, 95% confidence interval (CI) -0.54 to 0.10). We identified 1736 total unique NIH grants, with 23.8% of funded projects having women PIs. There was an increase in the proportion of women PIs over time (+1.31% per year, 95% CI 0.784 to 1.855; P < 0.001). Projects with women PIs received mean total awards that were significantly lower than projects with men PIs ($350,485 ± $220,072 vs. $451,493 ± $411,040; P < 0.001), but the overall ratio of funding:women investigators improved over time (+$11,531 per year, 95% CI $6,167 to $16,895; P = 0.0011). CONCLUSIONS: While we have made strides in increasing the number of women in the surgical research space, there is still room for improvement in funding parity. In addition, we found substantial and persistent room for improvement in representation of women in surgical innovation. As we enter a new frontier of surgery hallmarked by equalizing gender representation, these data should serve as a call-to-action for initiative aimed at rebuilding the foundation of surgical innovations upon equal gender representation.

Thoracic Endovascular Aortic RepairAcutely Augments Left Ventricular Biomechanics in An Animal Model: A Mechanism for Postoperative Heart Failure and Hypertension.

BACKGROUND: Thoracic aortic stent grafts are thought to decrease aortic compliance and may contribute to hypertension and heart failure after thoracic endovascular aortic repair (TEVAR). Left ventricular (LV) biomechanics immediately after TEVAR, however, have not been quantified. Pressure-volume (PV) loop analysis provides gold-standard LV functional information. The aim of this study is to use an LV PV loop catheter and analysis to characterize the LV biomechanics before and acutely after TEVAR. METHODS: Anesthetized Yorkshire swine (N = 6) were percutaneously instrumented with an LV PV loop catheter. A 20 mm × 10 cm stent graft was deployed distal to the left subclavian via the femoral artery under fluoroscopy. Cardiac biomechanics were assessed before and after TEVAR. As a sensitivity analysis, inferior vena cava occlusion with PV loop assessment was performed pre and post-TEVAR in 1 animal to obtain preload and afterload-independent end-systolic and end-diastolic PV relationships (ESPVR and EDPVR). RESULTS: All animals underwent successful instrumentation and TEVAR. Post-TEVAR, all 6 animals had higher mean LV ESP (106 vs. 118 mm Hg, P = 0.04), with no change in the EDPVR. inferior vena cava occlusion also moved the ESPVR curve upward and leftward, indicating increased LV work per unit time. There was no augmentation of EDPVR following TEVAR (P > 0.05). Postmortem exams in all animals revealed appropriate stent placement and no technical complications. CONCLUSIONS: TEVAR was associated with an acute increase in LV end-systolic pressure and shift in the ESPVR, indicating increased ventricular work. This data provides potential mechanistic insights into the development of post-TEVAR hypertension and heart failure. Future stent graft innovation should focus on minimizing the changes in cardiac physiology.

Endovascular stenting techniques for blunt carotid injury.

OBJECTIVES: While methods of endovascular carotid artery stenting have improved over time, concerns surrounding the safety and efficacy of stenting for blunt carotid injury (BCI) remain. This study aims to present our approach to carotid artery stenting (CAS) by incorporating new technologies such as flow-diverting stents and circuits. METHODS: There is no robust evidence to support routine carotid artery stenting; however, there are several therapeutic options and approaches for treating BCI that currently require an individualized approach. Endovascular stenting and specific stent selection are largely dictated by the disease process the surgeon intends to treat. We will discuss patient selection, medical management, and the most common revascularization techniques, including transfemoral stenting, trans-carotid arterial revascularization using flow reversal, and stent-assisting coiling. RESULTS: It must be stressed that endovascular intervention is not an alternative to or preclusive of antithrombotic or anticoagulant therapy. In the setting of BCI, transfemoral CAS is most appropriate in patients who are symptomatic, have a rapidly progressing or large lesion, and do not have a soft thrombus present due to risk of embolism. Unlike transfemoral CAS, TCAR offers an elegant solution for embolic protection when patients have a soft thrombus present. In the case of a large pseudoaneurysm, we perform stent-assisted coiling. CONCLUSIONS: We practice selective endovascular intervention, stenting lesions that are flow-limiting or have large or rapidly expanding pseudoaneurysms, and only in patients for whom anticoagulation and antiplatelet agents are not contraindicated. As technology and investigation progress, the concerns regarding the safety and the role of endovascular intervention in the treatment of BCI will be more clearly defined.

Contemporary management and time to revascularization in upper extremity arterial injury.

INTRODUCTION: Upper extremity arterial injury is associated with significant morbidity and mortality for trauma patients, but there is a paucity of data to guide the clinician in the management of these injuries. The goals of this review were to characterize the demographics, presentation, clinical management, and outcomes, and to evaluate how time to intervention associates with outcomes in trauma patients with upper extremity vascular injuries. METHODS: The National Trauma Data Bank (NTDB) Research Data Set for the years 2007-2016 was queried in order to identify adult patients (age ≥ 18) with an upper extremity arterial injury. Patients with brachiocephalic, subclavian, axillary, or brachial artery injury using the 1998 and 2005 versions of the Abbreviated Injury Scale were included. Patients with non-survivable injuries to the brain, traumatic amputation, or other major arterial injuries to the torso or lower extremities were excluded. RESULTS: The data from 7908 patients with upper extremity arterial injuries was reviewed. Of those, 5407 (68.4%) underwent repair of the injured artery. The median Injury Severity Score (ISS) was 10 (IQR = 7-18), and 7.7% of patients had a severe ISS (≥ 25). Median time to repair was 120 min (IQR = 60-240 min). Management was open repair in 52.3%, endovascular repair in 7.3%, and combined open and endovascular repairs in 8.8%; amputation occurred in 1.8% and non-operative management was used in 31.6% of patients. Blunt mechanism of injury, crush injury, concomitant fractures/dislocations, and nerve injuries were associated with amputation, whereas simultaneous venous injury was not. There was a significant decrease in the rate of amputation when patients undergoing surgical revascularization did so within 90 min of injury (P = 0.007). CONCLUSION: Injuries to arteries of the upper extremity are managed with open repair, endovascular repair, and, rarely, amputation. Expeditious transport to the operating room for revascularization is the key for limb salvage.

How to TEVAR swine for scientific research: Technical, anatomic, and device considerations to translate human TEVAR techniques into the large animal laboratory.

OBJECTIVE: Thoracic Endovascular Aortic Repair (TEVAR) is well established in humans. Despite widespread use, additional research questions related to thoracic aortic stenting and endovascular innovation require large animal models. Translating human TEVAR devices and techniques into animal models, however, is a challenge even for experienced endovascular surgeons looking to develop a large animal TEVAR model.This article describes swine-specific strategies to deploy human TEVAR stent grafts, delineate how to select, size, prepare, and re-use human stents and deployment systems in swine, and how to translate human imaging modalities to large animal TEVAR. METHODS: We describe a selection of related TEVAR models and techniques in Yorkshire swine to support scientific inquiry. This includes an animal husbandry and pre-operative preparation and planning program. All imaged specimens in this paper are castrated male Yorkshire swine in the 60-80 kg range and underwent TEVAR with the Medtronic Navion stent and deployment system. RESULTS: To study human aortic stent grafts in swine, the animals generally must be at least 50 kgs to guarantee a 2 cm internal aortic diameter at the left subclavian, and for the iliac arteries to accommodate the human deployment system. Swine will have longer torsos and shorter iliofemoral segments than a human of the same weight which can make human deployment systems too short to reach the left subclavian from the femoral arteries in larger animals. We provide techniques to overcome this, including open iliac access or upside-down carotid TEVAR, which may be particularly useful if the scientific data would be confounded by iliofemoral access.Unlike humans that present clinically with axial imaging, swine will generally not have preoperative imaging, and many translational research laboratories do not have access to inexpensive preoperative CT, or any intraoperative CT scanning, which we are fortunate to have. We describe, therefore, several strategies for imaging in this setting including TEVAR via C-arm fluoroscopy and with or without in-laboratory CT scanning. Due to the low-resource setting of most large animal laboratories, as compared to a human hybrid room, we also describe several techniques to reduce cost and reuse materials, including the stent grafts, which at the end of non-survival experiments can be recovered during necropsy, cleaned, reinserted into the deployment device and reused on additional animals. CONCLUSIONS: This article describes a collection of related techniques and tips to translate human TEVAR imaging, sizing/selection, deployment, and anatomy to swine research. Using this framework alone, an experienced human vascular or endovascular surgeon may develop a complete aortic stenting animal model with strategies for scientific data acquisition.

Postoperative antiplatelet and/or anticoagulation use does not impact complication or reintervention rates after vein repair of arterial injury: A PROOVIT study.

INTRODUCTION: The use of antiplatelet (AP) and anticoagulation (AC) therapy after autogenous vein repair of traumatic arterial injury is controversial. The hypothesis in this study was that there is no difference in early postoperative outcomes regardless of whether AC, AP, both, or neither are used. METHODS: The American Association for the Surgery of Trauma (AAST) PROspective Observational Vascular Injury Treatment (PROOVIT) registry was queried from November, 2013, to January, 2019, for arterial injuries repaired with a vein graft. Demographics and injury characteristics were compared. Need for in-hospital reoperation was the primary outcome in this four-arm study, assessed with two ordinal logistic regression models (1. no therapy vs. AC only vs. AC and AP; 2. no therapy vs. AP only vs. AC and AP). RESULTS: 373 patients (52 no therapy, 88 AP only, 77 AC only, 156 both) from 19 centers with recorded Injury Severity Scores (ISS) were identified. Patients who received no therapy were younger than those who received AP (27.0 vs. 34.2, p = 0.02), had higher transfusion requirement (p < 0.01 between all groups) and a different distribution of anatomic injury (p < 0.01). After controlling for age, sex, ISS, platelet count, hemoglobin, pH, lactate, INR, transfusion requirement and anatomic location, there was no association with postoperative medical therapy and in-hospital operative reintervention, or any secondary outcome, including thrombosis (p = 0.67, p = 0.22). CONCLUSIONS: Neither AC nor AP alone, nor in combination, impact complication rate after arterial repair with autologous vein. These patients can be safely treated with or without antithrombotics, recognizing that this study did not demonstrate a beneficial effect.

A Pilot Machine Learning Study Using Trauma Admission Data to Identify Risk for High Length of Stay.

INTRODUCTION: Trauma patients have diverse resource needs due to variable mechanisms and injury patterns. The aim of this study was to build a tool that uses only data available at time of admission to predict prolonged hospital length of stay (LOS). METHODS: Data was collected from the trauma registry at an urban level one adult trauma center and included patients from 1/1/2014 to 3/31/2019. Trauma patients with one or fewer days LOS were excluded. Single layer and deep artificial neural networks were trained to identify patients in the top quartile of LOS and optimized on area under the receiver operator characteristic curve (AUROC). The predictive performance of the model was assessed on a separate test set using binary classification measures of accuracy, precision, and error. RESULTS: 2953 admitted trauma patients with more than one-day LOS were included in this study. They were 70% male, 60% white, and averaged 47 years-old (SD: 21). 28% were penetrating trauma. Median length of stay was 5 days (IQR 3-9). For prediction of prolonged LOS, the deep neural network achieved an AUROC of 0.80 (95% CI: 0.786-0.814) specificity was 0.95, sensitivity was 0.32, with an overall accuracy of 0.79. CONCLUSION: Machine learning can predict, with excellent specificity, trauma patients who will have prolonged length of stay with only physiologic and demographic data available at the time of admission. These patients may benefit from additional resources with respect to disposition planning at the time of admission.

Association of carotid revascularization approach with perioperative outcomes based on symptom status and degree of stenosis among octogenarians.

OBJECTIVE: Age ≥80 years is known to be an independent risk factor for periprocedural stroke after transfemoral carotid artery stenting (TF-CAS) but not after carotid endarterectomy (CEA). The objective of the present study was to compare the perioperative outcomes for CEA, TF-CAS, and transcarotid artery revascularization (TCAR) among octogenarian patients (aged ≥80 years) overall and stratified by symptom status and degree of stenosis. METHODS: All patients aged ≥80 years with 50% to 99% carotid artery stenosis who had undergone CEA, TF-CAS, or TCAR in the Vascular Quality Initiative (2005-2020) were included. We compared the perioperative (30-day) incidence of ipsilateral stroke or death for CEA vs TF-CAS vs TCAR using analysis of variance and multivariable logistic regression models. The results were confirmed in a sensitivity analysis stratified by symptom status and degree of stenosis. RESULTS: Overall, 28,571 carotid revascularization procedures were performed in patients aged ≥80 years: CEA, n = 20,912 (73.2%), TF-CAS, n = 3628 (12.7%), and TCAR, n = 4031 (14.1%). The median age was 83 years (interquartile range, 81.0-86.0 years); 49.8% of the patients were symptomatic (51.9% CEA, 46.2% TF-CAS, 42.4% TCAR); and 60.7% had high-grade stenosis (59.0% CEA, 65.2% TF-CAS, 65.4% TCAR). Perioperative stroke/death occurred most frequently following TF-CAS (6.6%), followed by TCAR (3.1%) and CEA (2.5%; P < .001). After adjusting for baseline differences between groups, the odds ratio (OR) for stroke/death was greater for TF-CAS vs CEA (adjusted OR [aOR], 3.35; 95% confidence interval [CI], 2.65-4.23), followed by TCAR vs CEA (aOR 1.49, 95% CI 1.18-1.87). The risk of perioperative stroke/death remained significantly greater for TF-CAS compared with CEA regardless of symptom status and degree of stenosis (P < .05 for all). In contrast, the risk of stroke/death was higher for TCAR vs CEA for asymptomatic patients (aOR, 2.04; 95% CI, 1.41-2.94) and those with high-grade stenosis (aOR, 1.49; 95% CI, 1.11-2.05) but similar for patients with symptomatic and moderate-grade disease (P > .05 for both). The risk of myocardial infarction was lower with TCAR (aOR, 0.59; 95% CI, 0.40-0.87) and TF-CAS (aOR, 0.56; 95% CI, 0.40-0.87) compared with CEA overall. CONCLUSIONS: Overall, TCAR and CEA can be safely offered to older adults, in particular, symptomatic patients and those with moderate-grade stenosis. TF-CAS should be avoided in older patients when possible.

Transcarotid artery revascularization is associated with similar outcomes to carotid endarterectomy regardless of patient risk status.

BACKGROUND: Carotid artery stenting (CAS), including both transfemoral carotid artery stenting (TFCAS) and transcarotid artery revascularization (TCAR), reimbursement has been limited to high-risk patients by the Centers for Medicare & Medicaid Services (CMS) since 2005. We aimed to assess the association of CMS high-risk status with perioperative outcomes for carotid endarterectomy (CEA), TFCAS, and TCAR. METHODS: We performed a retrospective review of all Vascular Quality Initiative patients who underwent carotid revascularization between 2015 and 2020. Patients were stratified by whether they met CMS CAS criteria, and univariable and multivariable logistic regression analyses were performed to assess the association of procedure type (CEA, TFCAS, TCAR) with perioperative outcomes. RESULTS: Of 124,531 individuals who underwent carotid revascularization procedures, 91,687 (73.6%) underwent CEA, 17,247 (13.9%) underwent TFCAS, and 15,597 (12.5%) underwent TCAR. Among patients who met the CMS CAS criteria (ie, high-risk patients), the incidence of perioperative stroke was 2.7% for CEA, 3.4% for TFCAS, and 2.4% for TCAR (P < .001). Among standard-risk patients, the incidence of perioperative stroke was 1.7% for CEA, 2.7% for TFCAS, and 1.8% for TCAR (P < .001). After adjusting for baseline demographic and clinical characteristics, the odds of perioperative stroke were lower for TCAR versus CEA in high-risk patients (adjusted odds ratio [aOR], 0.82; 95% confidence interval [CI], 0.68-0.99) and similar in standard-risk patients (aOR, 1.05; 95% CI, 0.84, 1.31). In contrast, the adjusted odds of perioperative stroke were higher for TFCAS versus CEA in high-risk patients (aOR, 1.23; 95% CI, 1.03-1.46) and standard-risk patients (aOR, 1.60; 95% CI, 1.37-1.86). In both populations, TFCAS and TCAR patients had significantly lower odds of myocardial infarction than CEA patients (both P < .001). CONCLUSIONS: The perioperative risks associated with CEA, TFCAS, and TCAR in high-risk patients support the current CMS criteria, although the risks associated with each revascularization approach in standard-risk patients suggest that distinguishing TCAR from TFCAS may be warranted.

Index atherectomy peripheral vascular interventions performed for claudication are associated with more reinterventions than nonatherectomy interventions.

OBJECTIVE: Despite limited evidence supporting atherectomy alone over stenting/angioplasty as the index peripheral vascular intervention (PVI), the use of atherectomy has rapidly increased in recent years. We previously identified a wide distribution of atherectomy practice patterns among US physicians. The aim of this study was to investigate the association of index atherectomy with reintervention. METHODS: We used 100% Medicare fee-for-service claims to identify all beneficiaries who underwent elective first-time femoropopliteal PVI for claudication between January 1, 2019, and December 31, 2019. Subsequent PVI reinterventions were examined through June 30, 2021. Kaplan-Meier curves were used to compare rates of PVI reinterventions for patients who received index atherectomy versus nonatherectomy procedures. Reintervention rates were also described for physicians by their overall atherectomy use (by quartile). A hierarchical Cox proportional hazard model was used to evaluate patient and physician-level characteristics associated with reinterventions. RESULTS: A total of 15,246 patients underwent an index PVI for claudication in 2019, of which 59.7% were atherectomy. After a median of 603 days (interquartile range, 77-784 days) of follow-up, 41.2% of patients underwent a PVI reintervention, including 48.9% of patients who underwent index atherectomy versus 29.8% of patients who underwent index nonatherectomy (P < .001). Patients treated by high physician users of atherectomy (quartile 4) received more reinterventions than patients treated by standard physician users (quartiles 1-3) (56.8% vs 39.6%; P < .001). After adjustment, patient factors association with PVI reintervention included receipt of index atherectomy (adjusted hazard ratio [aHR], 1.33; 95% confidence interval [CI], 1.21-1.46), Black race (vs White; aHR; 1.18; 95% CI, 1.03-1.34), diabetes (aHR, 1.13; 95% CI, 1.07-1.21), and urban residence (aHR, 1.11; 95% CI, 1.01-1.22). Physician factors associated with reintervention included male sex (aHR, 1.52; 95% CI, 1.12-2.04), high-volume PVI practices (aHR, 1.23; 95% CI, 1.10-1.37), and physicians with a high use of index atherectomy (aHR, 1.49; 95% CI, 1.27-1.74). Vascular surgeons had a lower risk of PVI reintervention than cardiologists (vs vascular; aHR, 1.22; 95% CI, 1.09-1.38), radiologists (aHR, 1.55; 95% CI, 1.31-1.83), and other specialties (aHR, 1.59; 95% CI, 1.20-2.11). The location of services delivered was not associated with reintervention (P > .05). CONCLUSIONS: The use of atherectomy as an index PVI for claudication is associated with higher PVI reintervention rates compared with nonatherectomy procedures. Similarly, high physician users of atherectomy perform more PVI reinterventions than their peers. The appropriateness of using atherectomy for initial treatment of claudication needs critical reevaluation.

Characterizing Brain Perfusion in a Swine Model of Raised Intracranial Pressure.

INTRODUCTION: Perfusion of the brain is critical, but this can be compromised due to focal space occupying lesions (SOL). SOLs can raise intracranial pressure (ICP), resulting in reduced cerebral blood flow (CBF). Most gyrencephalic models of brain injury focus on parenchymal injury, with few models of acutely elevated ICP. We hypothesized that we could employ a SOL technique to develop a titratable ICP model and sought to quantitate the resulting decrease in brain perfusion. METHODS: Six swine were anesthetized and instrumented. A Fogarty balloon catheter was inserted intracranially. Blood CO2 partial pressure was maintained between 35 and 45 mmHg. The Fogarty balloon was infused with normal saline at 1 mL/min to ICP targets of 10, 20, 30, and 40 mmHg. CBF (mL/100 g/min) were assessed at each ICP level using computed tomography perfusion (CTP). Data are presented as the mean ± standard deviation with all pressures measured in mmHg. CBF values were compared between baseline and each ICP level using analysis of variance. RESULTS: Baseline ICP was 5 ± 2 and systolic blood pressure was 106 ± 7. Balloon volumes (mL) required to achieve each incremental ICP level were 2.4 ± 0.5, 4.9 ± 1.7, 7.6 ± 1.6, and 9.9 ± 1.7. CBF decreased with each raised ICP level, with CBF being significantly less than baseline at ICP values of 30 (56.1 ± 34.7 versus 20.6 ± 11.0, P < 0.05) and 40 (56.1 ± 34.7 versus 6.5 ± 10.6, P < 0.05). CONCLUSIONS: An intracranial balloon catheter can be used to increase ICP, delivering a proportionate reduction in CBF. This model can be used in the future studies to examine adjuncts that manipulate intracranial pressure and their effect on brain perfusion.

Drug-Eluting Stents are Associated with Superior Mid-Term Outcomes for the Treatment of Infrainguinal Bypass Graft Stenoses.

BACKGROUND: We previously demonstrated that everolimus drug-eluting stents (eDES) have reasonable short-term patency for the treatment of infrainguinal bypass stenoses. The aim of this study is to compare mid-term outcomes of eDES, plain balloon angioplasty (PTA), percutaneous cutting balloon (PCB), and drug-coated balloon (DCB) interventions for failing infrainguinal bypasses. METHODS: We conducted a retrospective review of patients with infrainguinal bypass stenoses treated by endovascular intervention (August 2010-August 2021). The primary outcome was primary patency (PP). Secondary outcomes were primary-assisted patency (PAP), secondary patency (SP), limb salvage (LS), and mortality. Outcomes were compared by treatment using Kaplan-Meier curves with log-rank tests and Cox proportional hazards models adjusting for baseline differences between groups. RESULTS: Seventy-two consecutive patients with 152 discrete infrainguinal bypass graft stenoses were identified. Mean age was 65.1 ± 10.6 years, 55.6% were male, and 48.6% were Black. In total, 81.9% of patients were originally treated for chronic limb-threatening ischemia, and 57.2% of distal anastomoses were to tibial or pedal targets. Of 152 lesions, 44.1% (n = 67) were treated with PTA, 17.8% (n = 27) with PCB, 20.4% (n = 31) with DCB, and 17.8% (n = 27) with eDES. Median follow-up was 28.5 months (interquartile range 11.5-51.9). There was no difference in bypass configuration, conduit choice, or stenosis location (proximal anastomosis, mid-bypass, distal anastomosis) between groups. At 24 months postintervention, PP was significantly better for eDES (72.9%, 95% confidence interval [CI] 49.8-85.6), followed by PCB (55.9%, 95% CI 34.2-72.9), PTA (34.4%, 95% CI 21.7-47.4), and DCB (33.6%, 95% CI 14.5-53.9) (P = 0.03). PAP, LS, and mortality did not significantly differ between modalities (P > 0.05). After risk adjustment, eDES was associated with the lowest risk of PP loss (hazard ratio versus PTA 0.15, 95% CI 0.05-0.47). CONCLUSIONS: eDES is associated with superior 24-month patency rates compared to other endovascular technologies, and should be considered a primary therapy modality for the treatment of infrainguinal bypass graft stenoses.

Ectopic Fetal Hepatic Tissue in the Placenta.

When an unusual intraplacental lesion is identified during pathologic examination, it becomes of substantial import to determine whether it represents a normal structure, metastasis from the mother, or a primary benign tumor, including those secondary to abnormal embryologic development versus a primary malignant placental tumor. In this case report, we identified an incidental nest of intraplacental cells with nondiagnostic morphology and negative initial Glypican-3 stain in a healthy 35-wk gestation. This negative result prompted a broadening of the differential before ultimately determining this lesion was indeed ectopic liver with positive Arginase-1 and HepPar-1 staining. This may represent the mature hepatocyte phenotype within the lesional cells of this near-term birth, a dichotomy not previously discussed in the literature, which focuses on the fetal hepatocyte phenotype, also rarely seen. In this report, we summarize the previous literature regarding intraplacental ectopic liver, and we propose a sensitive approach to suspected ectopic liver of the placenta that may be sufficient to capture both the fetal and mature hepatocyte immunophenotypes. This approach may extend to other related pathologies including assessment of suspected intraumbilical hepatocytes.

Machine learning analyses can differentiate meningioma grade by features on magnetic resonance imaging.

OBJECTIVEPrognostication and surgical planning for WHO grade I versus grade II meningioma requires thoughtful decision-making based on radiographic evidence, among other factors. Although conventional statistical models such as logistic regression are useful, machine learning (ML) algorithms are often more predictive, have higher discriminative ability, and can learn from new data. The authors used conventional statistical models and an array of ML algorithms to predict atypical meningioma based on radiologist-interpreted preoperative MRI findings. The goal of this study was to compare the performance of ML algorithms to standard statistical methods when predicting meningioma grade.METHODSThe cohort included patients aged 18-65 years with WHO grade I (n = 94) and II (n = 34) meningioma in whom preoperative MRI was obtained between 1998 and 2010. A board-certified neuroradiologist, blinded to histological grade, interpreted all MR images for tumor volume, degree of peritumoral edema, presence of necrosis, tumor location, presence of a draining vein, and patient sex. The authors trained and validated several binary classifiers: k-nearest neighbors models, support vector machines, naïve Bayes classifiers, and artificial neural networks as well as logistic regression models to predict tumor grade. The area under the curve-receiver operating characteristic curve was used for comparison across and within model classes. All analyses were performed in MATLAB using a MacBook Pro.RESULTSThe authors included 6 preoperative imaging and demographic variables: tumor volume, degree of peritumoral edema, presence of necrosis, tumor location, patient sex, and presence of a draining vein to construct the models. The artificial neural networks outperformed all other ML models across the true-positive versus false-positive (receiver operating characteristic) space (area under curve = 0.8895).CONCLUSIONSML algorithms are powerful computational tools that can predict meningioma grade with great accuracy.