Female and male patients have similar outcomes after transcarotid artery revascularization in prospective trials.

OBJECTIVE: Sex disparities in outcomes after carotid revascularization have long been a concern, with several studies demonstrating increased postoperative death and stroke for female patients after either carotid endarterectomy or transfemoral stenting. Adverse events after transfemoral stenting are higher in female patients, particularly in symptomatic cases. Our objective was to investigate outcomes after transcarotid artery revascularization (TCAR) stratified by patient sex hypothesizing that the results would be similar between males and females. METHODS: We analyzed prospectively collected data from the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER)1 (pivotal), ROADSTER2 (US Food and Drug Administration indicated postmarket), and ROADSTER Extended Access TCAR trials. All patients had verified carotid stenosis meeting criteria for intervention (≥80% for asymptomatic patients and ≥50% in patient with symptomatic disease), and were included based on anatomical or clinical high-risk criteria for carotid stenting. Neurological assessments (National Institutes of Health Stroke Scale, Modified Rankin Scale) were obtained before and within 24 hours from procedure end by an independent neurologist or National Institutes of Health Stroke Scale-certified nurse. Patients were stratified by sex (male vs female). Baseline demographics were compared using χ2 and Fisher's exact tests where appropriate; primary outcomes were combination stroke/death (S/D) and S/D/myocardial infarction (S/D/M) at 30 days, and secondary outcomes were the individual components of S/D/M. Univariate logistic regression was conducted. RESULTS: We included 910 patients for analysis (306 female [33.6%], 604 male [66.4%]). Female patients were more often <65 years old (20.6% vs 15%) or ≥80 years old (22.6% vs 20.2%) compared with males, and were more often of Black/African American ethnicity (7.5% vs 4.3%). There were no differences by sex in term of comorbidities, current or prior smoking status, prior stroke, symptomatic status, or prevalence of anatomical and/or clinical high-risk criteria. General anesthetic use, stent brands used, and procedure times did not differ by sex, although flow reversal times were longer in female patients (10.9 minutes male vs 12.4 minutes female; P = .01), as was more contrast used in procedures for female patients (43 mL male vs 48.9 mL female; P = .049). The 30-day S/D and S/D/M rates were similar between male and female patients (S/D, 2.7% male vs 1.6% female [P = .34]; S/D/M, 3.6% male vs 2.6% female [P = .41]), which did not differ when stratified by symptom status. Secondary outcomes did not differ by sex, including stroke rates at 30 days (2.2% male vs 1.6% female; P = .80), nor were differences seen with stratification by symptom status. Univariate analysis demonstrated that history of a prior ipsilateral stroke was associated with increased odds of S/D (odds ratio [OR], 4.19; P = .001) and S/D/M (OR, 2.78; P = .01), as was symptomatic presentation with increased odds for S/D (OR, 2.78; P = .02). CONCLUSIONS: Prospective TCAR trial data demonstrate exceptionally low rates of S/D/MI, which do not differ by patient sex.

Direct oral anticoagulants over warfarin at discharge associated with improved survival and patency in infra-geniculate bypasses with prosthetic conduits.

OBJECTIVE: There is no consensus on the optimal anticoagulant regimen following lower extremity bypass. Historically, warfarin has been utilized for prosthetic or compromised vein bypasses. Direct-acting oral anticoagulants (DOACs) are increasingly replacing warfarin in this context, but their efficacy in bypass preservation has not been well-studied. Recent studies have shown that DOACs may improve outcomes following bypasses; however, it is unclear if this is dependent upon type of bypass conduit. The goal of this study was to evaluate whether a difference exists between vein and prosthetic infra-geniculate bypasses outcomes based on the anticoagulant utilized on discharge, warfarin or DOAC. METHODS: The Vascular Quality Initiative infra-inguinal bypass database was queried for all patients who underwent an infra-geniculate bypass and were anticoagulation-naive at baseline but were discharged on either warfarin or DOACs. A survival analysis was performed for patients up to 1 year to determine whether the choice of discharge anticoagulation was associated with differences between those with vein vs prosthetic conduits in overall survival, primary patency, risk of amputation, or risk of major adverse limb events (MALE). A multivariable Cox proportional hazards analysis was performed to control for differences in baseline demographic factors between the groups. RESULTS: During the study period (2003-2020), 57,887 patients underwent infra-geniculate bypass. Of these, 3230 (5.5%) were anticoagulated on discharge. There was a similar distribution of anticoagulation between vein (n = 1659; 51.4%) and prosthetic conduits (n = 1571; 48.6%). Thirty-two percent were discharged on DOACs, and 68.0% were discharged on warfarin. For prosthetic conduits, being discharged on a DOAC was associated with improved outcomes on univariate and multivariable analyses revealing lower risk of overall mortality (hazard ratio [HR], 0.61; 95% confidence interval [CI], 0.41-0.93; P = .021), loss of primary patency (HR, 0.70; 95% CI, 0.55-0.89; P = .003), risk of amputation (HR, 0.71; 95% CI, 0.54-0.93; P = .013), and risk of MALE (HR, 0.80; 95% CI, 0.64-1.00; P = .048). Patients with a vein bypass had improved univariate outcomes for survival and primary patency; however, with multivariable analysis, there were no significant differences in outcomes between DOAC and warfarin. CONCLUSIONS: Anticoagulation-naive patients who underwent an infra-geniculate prosthetic bypass had higher rates of overall survival, bypass patency, amputation-free survival, and freedom from MALE when discharged on a DOAC compared with warfarin. Those with vein bypasses had similar outcomes regardless of the choice of anticoagulation.

Outcome after revascularization with paclitaxel-coated devices in patients with chronic limb-threatening ischemia.

OBJECTIVE: Data regarding the safety and efficacy of paclitaxel (PTX)-coated peripheral arterial devices for femoropopliteal artery (FPA) atherosclerotic disease is derived from studies that mainly evaluated patients with claudication. Outcomes of PTX treatment for patients with chronic limb-threatening ischemia (CLTI) is incompletely defined. This study compares outcome in patients with CLTI treated with and without PTX. METHODS: We retrospectively studied patients who underwent FPA intervention for an indication of CLTI in the Vascular Quality Initiative peripheral vascular intervention database from 2016 to 2020. Patients who had concomitant iliac or tibial interventions were included. One limb per patient was studied. Propensity score matching based on demographics, comorbidities, indication, and pharmacological therapy was performed to generate balanced cohorts. Kaplan-Meier survival analysis and multivariate Cox regression compared limb salvage, overall survival, primary patency, and major adverse limb events (MALE) between patients treated with and without PTX. RESULTS: Demographics, comorbidities, indications, and procedural details were similar between 14,065 PTX and 14,065 non-PTX propensity-matched patients. Kaplan-Meier analysis at 18-month follow-up demonstrated that the PTX group compared with the non-PTX group had a significantly higher rates of limb salvage (89.2% vs 86.5%; P < .001), primary patency (80.3% vs 76.9%; P < .001), and freedom from MALE (72.6% vs 67.9%; P < .001). Multivariate analysis also showed that PTX treatment was associated with a lower risk of major amputation (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.67-0.82; P < .001), loss of primary patency (HR, 0.80; 95% CI, 0.74-0.87; P < .001), and MALE (HR, 0.77; 95% CI, 0.72-0.82; P < .001). Overall, 21% of patients had a prior ipsilateral peripheral vascular intervention. Removing these patients from the analysis yielded similar results at 18 months. Overall survival at 54 months was not statistically different between the PTX and non-PTX groups in the overall cohort (73.5 vs 71.3%; P = .07), but significant in the de-novo treated patients (73.9% vs 70.7%; P = .02).Multivariate analyses showed a lower mortality risk in the PTX patients (HR, 0.93; 95% CI, 0.87-0.98; P = .02). CONCLUSIONS: FPA intervention with a PTX-coated device is associated with improved limb salvage, primary patency, and freedom from MALE at the 18-month follow-up compared with uncoated devices. This benefit was not associated with an increase in all-cause mortality out to 4.5 years. Further study is necessary to determine the optimal role for PTX in the treatment of the FPA for patients with CLTI and to understand its long-term outcome.

Trends and outcomes associated with intravascular ultrasound use during femoropopliteal revascularization in the Vascular Quality Initiative.

OBJECTIVE: Intravascular ultrasound (IVUS) use in lower extremity interventions is growing in popularity owing to its imaging in the axial plane, superior detail in imaging lesion characteristics, and its enhanced ability to delineate lesion severity and extent compared with catheter angiograms. However, there are conflicting data regarding whether IVUS affects outcomes. The purpose of this study was to assess the effect associated with IVUS implementation in femoropopliteal interventions. METHODS: This retrospective cohort study used Vascular Quality Initiative data. Patients undergoing an index endovascular femoropopliteal revascularization from 2016 to 2021 were included. Patients were differentiated by whether or not IVUS was used to assess the femoropopliteal segment during intervention (no IVUS, IVUS). Propensity score matching, based on preoperative demographics and measures of disease severity was used. Primary outcomes were major amputation-free survival (AFS), femoropopliteal reintervention-free survival (RFS), and primarily patent survival (PPS) at 12 months. RESULTS: IVUS use grew steadily throughout the study period, comprising 0.6% of interventions in 2016 and increasing to 8.2% of interventions by 2021; growth was most dramatic in ambulatory surgical center or office-based laboratory settings where IVUS use grew from 4.4% to 43% to 47% of interventions. In unmatched cohorts, patients receiving interventions using IVUS tended to have lower prevalence of multiple cardiovascular comorbidities (eg, congestive heart failure, hypertension, diabetes, and dialysis dependence) and presented more often with claudication and less often with chronic limb-threatening ischemia (CLTI). Intraoperatively, IVUS was used more often in complex femoropopliteal lesions (Transatlantic Intersociety grade D vs A), and more often in conjunction with stenting and/or atherectomy. IVUS use was associated with improved AFS, but similar RFS and PPS at 12 months. However, in multivariable analysis IVUS was not associated with any of the primary outcomes independently; rather, all outcomes were influenced primarily by CLTI, dialysis dependence, and prior major amputation status; technical outcomes (ie, RFS and PPS loss) were further driven by complexity of lesion (worse in Transatlantic Intersociety grade D vs A lesions) and treatment setting (ie, ambulatory surgical center or office-based laboratory setting associated with increased hazard for RFS and PPS loss). CONCLUSIONS: IVUS implementation in femoropopliteal interventions is growing, with rapid adoption among interventions in ambulatory surgical centers and office-based laboratories. IVUS was not associated with an effect on technical outcomes at 12 months; improvement in major AFS was observed; however, multivariable analysis suggests this finding may be an effect of confounding by multiple factors highly associated with IVUS use, namely, in patients with lower prevalence of CLTI, dialysis dependence, and prior major amputations, thus conveying baseline lower risk for major amputation and death.

Use of direct-acting oral anticoagulants associated with improved survival and bypass graft patency compared with warfarin after infrageniculate bypass.

OBJECTIVE: No consensus has yet been reached regarding the optimal antiplatelet and anticoagulant regimen for patients after lower extremity bypass. Usually, patients who have undergone below-the-knee bypass will begin oral anticoagulation therapy. Historically, the bypass has been with prosthetic conduits and the anticoagulation therapy has been warfarin. However, the use of direct-acting oral anticoagulants (DOACs) has been increasing owing to their relative ease of dosing. The goal of the present study was to evaluate whether a difference exists in the postoperative outcomes for patients who have undergone infrageniculate bypass stratified by the use of on DOACs vs warfarin. METHODS: The Vascular Quality Initiative infrainguinal bypass database was queried for all patients who had undergone infrageniculate bypass, been anticoagulation naive at baseline, and been discharged with anticoagulation therapy. A survival analysis was performed for patients for ≤2 years postoperatively to determine whether discharge with warfarin vs DOACs was associated with differences in overall mortality, loss of primary patency, risk of amputation, and risk of major adverse limb events (MALE). A multivariable Cox proportional hazards analysis was performed to control for differences in the baseline demographic factors between the two groups. RESULTS: During the study period (2007-2020) 57,887 patients had undergone infrageniculate bypass. Of these patients, 2786 had been anticoagulation naive and discharged with either warfarin (n = 1889) or DOACs (n = 897). Discharge with a DOAC was associated with a lower risk of overall mortality (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.47-0.83; P = .001), loss of primary patency (HR, 0.74; 95% CI, 0.62-0.87; P < .001), risk of amputation (HR, 0.70; 95% CI, 0.57-0.86; P = .001), and risk of MALE (HR, 0.83; 95% CI, 0.71-0.97; P = .017). CONCLUSIONS: Anticoagulation-naive patients who had undergone infrageniculate bypass had had higher rates of overall survival, bypass patency, amputation-free survival, and freedom from MALE when discharged with a DOAC than with warfarin.

Precocious Rupture of Abdominal Aortic Aneurysms Below Size Criteria for Repair: Risk Factors and Outcomes.

BACKGROUND: Practice guidelines recommend elective repair for abdominal aortic aneurysms (AAAs) ≥ 5.5 cm in men and ≥ 5 cm in women to prevent rupture; however, some rupture at smaller diameters. We identify risk factors for rupture AAA (rAAA) below this threshold and compare outcomes following rAAA repair above/below size criteria. METHODS: The Vascular Quality Initiative (2013-2019) was queried for patients undergoing repair for rAAA and stratified based on diameter into small and large cohorts [Small: < 5.5 cm (men), < 5.0 cm (women)]. Univariate analysis was performed, and Kaplan-Meier analysis compared overall survival, aneurysm-related mortality, and reintervention at 12 months. RESULTS: Five thousand one hundred sixty two rAAA were identified. Small rAAA patients [n = 588] were more likely to have hypertension (81.3% vs. 77.0%, P < 0.02), diabetes (18.2% vs. 14.9%, P < 0.04), and end-stage renal disease (2.9% vs. 0.9%, P < 0.01) and be on optimal medical therapy (32.1% vs. 26.8%, P < 0.01). Women were more likely to rupture at smaller diameters compared to men (P < 0.01). Small rAAA patients were more likely to undergo endovascular aortic repair (EVAR) (70.2% vs. 56.0%, P < 0.01) and had lower in-hospital mortality (17.7% vs. 27.7%, P < 0.01) and fewer perioperative complications across all categories. At 12 months, small rAAA patients had better overall survival, freedom from aneurysm-related mortality, and freedom from reintervention, largely driven by EVAR approach. CONCLUSIONS: More than 11% of patients presenting with ruptured AAA were below the recommended size threshold for repair, and they tended to be younger, non-White, and have hypertension, diabetes, and/or renal failure. Patients with small rAAA experienced lower in-hospital morbidity and mortality and improved 1-year survival, and EVAR was associated with better outcomes than open repair. However, women more frequently rupture at smaller diameters compared to men. Given contemporary elective outcomes for women, a randomized controlled trial for EVAR versus surveillance at a sex-specific size threshold is needed.

An Angiotensin-Responsive Connection from the Lamina Terminalis to the Paraventricular Nucleus of the Hypothalamus Evokes Vasopressin Secretion to Increase Blood Pressure in Mice.

Blood pressure is controlled by endocrine, autonomic, and behavioral responses that maintain blood volume and perfusion pressure at levels optimal for survival. Although it is clear that central angiotensin type 1a receptors (AT1aR; encoded by the Agtr1a gene) influence these processes, the neuronal circuits mediating these effects are incompletely understood. The present studies characterize the structure and function of AT1aR neurons in the lamina terminalis (containing the median preoptic nucleus and organum vasculosum of the lamina terminalis), thereby evaluating their roles in blood pressure control. Using male Agtr1a-Cre mice, neuroanatomical studies reveal that AT1aR neurons in the area are largely glutamatergic and send projections to the paraventricular nucleus of the hypothalamus (PVN) that appear to synapse onto vasopressin-synthesizing neurons. To evaluate the functionality of these lamina terminalis AT1aR neurons, we virally delivered light-sensitive opsins and then optogenetically excited or inhibited the neurons while evaluating cardiovascular parameters or fluid intake. Optogenetic excitation robustly elevated blood pressure, water intake, and sodium intake, while optogenetic inhibition produced the opposite effects. Intriguingly, optogenetic excitation of these AT1aR neurons of the lamina terminalis also resulted in Fos induction in vasopressin neurons within the PVN and supraoptic nucleus. Further, within the PVN, selective optogenetic stimulation of afferents that arise from these lamina terminalis AT1aR neurons induced glutamate release onto magnocellular neurons and was sufficient to increase blood pressure. These cardiovascular effects were attenuated by systemic pretreatment with a vasopressin-1a-receptor antagonist. Collectively, these data indicate that excitation of lamina terminalis AT1aR neurons induces neuroendocrine and behavioral responses that increase blood pressure.SIGNIFICANCE STATEMENT Hypertension is a widespread health problem and risk factor for cardiovascular disease. Although treatments exist, a substantial percentage of patients suffer from "drug-resistant" hypertension, a condition associated with increased activation of brain angiotensin receptors, enhanced sympathetic nervous system activity, and elevated vasopressin levels. The present study highlights a role for angiotensin Type 1a receptor expressing neurons located within the lamina terminalis in regulating endocrine and behavioral responses that are involved in maintaining cardiovascular homeostasis. More specifically, data presented here reveal functional excitatory connections between angiotensin-sensitive neurons in the lamina terminals and vasopressin neurons in the paraventricular nucleus of the hypothalamus, and further indicate that activation of this circuit raises blood pressure. These neurons may be a promising target for antihypertensive therapeutics.

Effect of intravascular ultrasound on clinical outcomes after thoracic endovascular aortic repair for blunt thoracic aortic injury.

OBJECTIVE: Thoracic endovascular aortic repair (TEVAR) for blunt traumatic aortic injuries (BTAIs) can be complicated by inaccurate aortic measurements at the initial computed tomography angiography secondary to hypovolemic shock. The use of intravascular ultrasound (IVUS) has been proposed for more accurate aortic sizing, with prior data demonstrating larger aortic sizes measured by IVUS, potentially altering the vast majority of chosen endograft sizes. At present, and to the best of our knowledge, no studies have examined whether IVUS affects the clinical outcomes. The purpose of the present study was to examine the effect of IVUS on the clinical outcomes after TEVAR for BTAIs. METHODS: A retrospective cohort study was performed of patients who had undergone TEVAR for BTAIs in the VQI registry. The cohorts were defined by the use of IVUS. The primary outcomes were mortality and reintervention at 1 year. RESULTS: A total of 919 patients who had undergone TEVAR for BTAIs were included in the present analysis. The IVUS patients had presented with higher injury severity scores (36.2 vs 42; P = .0004) largely because of more extremity and external trauma. IVUS was more often used for patients with grade III injuries (49.1% vs 56.9%; P = .02) and less often for patients with rupture (21.1% vs 12.4%; P = .001). A trend toward a delay in TEVAR was seen for the patients for whom IVUS was used (1.8 vs 3.5 days; P = .38), with additional trends toward reduced intraoperative resuscitation and blood loss. The hemodynamic status of the patients and differences in aortic or endograft sizes could not be assessed with the available data. IVUS use was not associated with any differences in survival or reintervention rates in-hospital or at 1 year (Kaplan-Meier survival estimates: 0.91 no IVUS vs 0.92 IVUS; P = .46). Fifteen aortic-related reinterventions occurred across the entire patient cohort for all-available follow-up with comparable rates of type I endoleaks (1 no IVUS vs 2 IVUS), with no recorded cases of sizing-related complications such as device rupture, migration, or dissection. CONCLUSIONS: IVUS usage during TEVAR for BTAIs was associated with clinical scenarios in which patients were more stable and interventions to address BTAIs can be delayed. Despite this, the overall clinical outcomes were similar between cases in which IVUS was used and for which it was not.

Physician-modified endografts are associated with a survival benefit over parallel grafting in thoracoabdominal aneurysms.

OBJECTIVE: Physician-modified endografts (PMEG) and parallel grafting (PG) are important techniques for endovascular repair of complex aortic aneurysms using off-the-shelf devices. However, there are few data regarding the relative efficacy and outcomes of these techniques in thoracoabdominal extent aneurysms. This study sought to compare the outcomes of PG and PMEG across different extents of thoracoabdominal aneurysms (TAAAs) for which they can be used. METHODS: The Society for Vascular Surgery Vascular Quality Initiative thoracic endovascular aortic repair/complex endovascular aortic repair module was queried for all patients undergoing repair of an unruptured, TAAA (extents I-IV) from 2012 to 2020; aneurysm types were defined by repair extent as determined by proximal and distal seal zones. Patients were differentiated based on whether they underwent repair with a PMEG or PG. The primary outcomes for this study were overall survival and freedom from aneurysm- or procedure-related mortality at 1 year determined via Kaplan-Meier analysis, with a Cox hazard regression analysis conducted to examine the independent association of repair modality with primary outcomes. RESULTS: There were 813 patients who met the inclusion criteria (TAAA I-III, n = 362; TAAA IV, n = 451; PG, n = 426; PMEG, n = 387). PMEG repairs were performed at centers with a nearly two- to three-fold higher annual volume of endovascular TAAA repairs. Type Ia endoleaks were reduced with PMEG repair, most significantly in TAAA IV (TAAA I-III, 2.2% PMEG vs 10% PG [P = .2]; TAAA IV, 1.2% PMEG vs 21.6% PG [P < .001]). Thoracoabdominal repairs demonstrated improved survival at 1 year with PMEG devices, significant for TAAA I to III repairs (TAAA I-III, PMEG 85% vs PG 74% [P = .01]; TAAA IV, 84% PMEG vs PG 78% [P = .08]). Freedom from aneurysm- or procedure-related mortality was also improved with PMEG repairs, remaining significant at 1 year in the case of TAAA IV (TAAA I-III:, PMEG 94% vs PG 86% [P = .06]; TAAA IV, PMEG 94% vs PG 88% [P = .02]). PMEG demonstrated decreases in several measures of postoperative morbidity, including stroke, death, major adverse cardiovascular events, and postoperative complications. In the multivariate analysis, repair modality was not associated with either primary outcome; rather, several perioperative complications conveyed the greatest hazard for both primary outcomes across repair extents. CONCLUSIONS: Survival after endovascular TAAA repair is improved with the use of PMEG compared with PG. Several key factors of this study demonstrate the shortcomings of PG in complex aneurysm repair, namely, high rates of critical endoleaks, the need for adjunctive access sites, and an increase in perioperative complications that influence longer term outcomes.

Oxytocin and cardiometabolic interoception: Knowing oneself affects ingestive and social behaviors.

Maintaining homeostasis while navigating one's environment involves accurately assessing and interacting with external stimuli while remaining consciously in tune with internal signals such as hunger and thirst. Both atypical social interactions and unhealthy eating patterns emerge as a result of dysregulation in factors that mediate the prioritization and attention to salient stimuli. Oxytocin is an evolutionarily conserved peptide that regulates attention to exteroceptive and interoceptive stimuli in a social environment by functioning in the brain as a modulatory neuropeptide to control social behavior, but also in the periphery as a hormone acting at oxytocin receptors (Oxtr) expressed in the heart, gut, and peripheral ganglia. Specialized sensory afferent nerve endings of Oxtr-expressing nodose ganglia cells transmit cardiometabolic signals via the Vagus nerve to integrative regions in the brain that also express Oxtr(s). These brain regions are influenced by vagal sensory pathways and coordinate with external events such as those demanding attention to social stimuli, thus the sensations related to cardiometabolic function and social interactions are influenced by oxytocin signaling. This review investigates the literature supporting the idea that oxytocin mediates the interoception of cardiovascular and gastrointestinal systems, and that the modulation of this awareness likewise influences social cognition. These concepts are then considered in relation to Autism Spectrum Disorder, exploring how atypical social behavior is comorbid with cardiometabolic dysfunction.

Canceled Air Ambulance Trauma Scene Calls: A Prospective Observational Study of Causes and Outcomes of Trauma Auto-launch Cancellations.

OBJECTIVE: Direct transport, occasionally by helicopter, to a trauma hospital for severely injured patients is associated with decreased mortality. This study sought to determine causes for air ambulance trauma response cancellations and secondarily to identify patients who underwent secondary transfer to a trauma center after a canceled air ambulance dispatch. METHODS: This prospective cohort study used administrative databases from August 2020 to August 2021 to collect data related to canceled trauma calls. Frequencies of cancellation reasons and transferred patients were summarized, and the estimated delay to trauma center arrival was calculated. Subsequent probabilistic matching was performed to identify patients who underwent secondary transfer. RESULTS: Of 3,232 trauma calls, 1,924 were canceled for reasons including the trauma bypass criteria not being met, patient brought to trauma center, and patient refused transfer. Of the 1,117 patients for whom an air ambulance was canceled because they did not meet the trauma bypass criteria, 184 (16.5%) were later transferred to a lead trauma hospital, with a median delay of 4.12 hours (interquartile range = 2.57-7.35 hours). CONCLUSIONS: Most scene call cancellations were due to patients not meeting the trauma bypass criteria; yet, 16.5% of these patients were later transported to a trauma center. Interventions are needed in education, adherence, and modification of the trauma bypass criteria.

A Quantitative Study of Particle Dispersion due to Respiratory Support Modalities in PC-12 Aircraft: Prehospital Patient Transport.

OBJECTIVE: It is unclear whether supplemental oxygen and noninvasive ventilation respiratory support devices increase the dispersion of potentially infectious bioaerosols in a pressurized air medical cabin. This study quantitatively compared particle dispersion from respiratory support modalities in an air medical cabin during flight. METHODS: Dispersion was measured in a fixed wing air ambulance during flight with a breathing medical mannequin simulator exhaling nebulized saline from the lower respiratory tract with the following respiratory support modalities: a nasal cannula with a surgical mask, high-flow nasal oxygen (HFNO) with a surgical mask, and noninvasive bilevel positive airway pressure (BiPAP) ventilation. RESULTS: Nasal cannula oxygen with a surgical mask was associated with the highest particle concentrations. In the absence of mask seal leaks, BiPAP was associated with 1 order of magnitude lower particle concentration compared with a nasal cannula with a surgical mask. Particle concentrations associated with HFNO with a surgical mask were lower than a nasal cannula with a surgical mask but higher than BiPAP. CONCLUSIONS: Particle dispersion associated with the use of BiPAP and HFNO with a surgical mask is lower than nasal cannula oxygen with a surgical mask. These findings may assist air medical organizations with operational decisions where little data exist about respiratory particle dispersion.

A Unique "Angiotensin-Sensitive" Neuronal Population Coordinates Neuroendocrine, Cardiovascular, and Behavioral Responses to Stress.

Stress elicits neuroendocrine, autonomic, and behavioral responses that mitigate homeostatic imbalance and ensure survival. However, chronic engagement of such responses promotes psychological, cardiovascular, and metabolic impairments. In recent years, the renin-angiotensin system has emerged as a key mediator of stress responding and its related pathologies, but the neuronal circuits that orchestrate these interactions are not known. These studies combine the use of the Cre-recombinase/loxP system in mice with optogenetics to structurally and functionally characterize angiotensin type-1a receptor-containing neurons of the paraventricular nucleus of the hypothalamus, the goal being to determine the extent of their involvement in the regulation of stress responses. Initial studies use neuroanatomical techniques to reveal that angiotensin type-1a receptors are localized predominantly to the parvocellular neurosecretory neurons of the paraventricular nucleus of the hypothalamus. These neurons are almost exclusively glutamatergic and send dense projections to the exterior portion of the median eminence. Furthermore, these neurons largely express corticotrophin-releasing hormone or thyrotropin-releasing hormone and do not express arginine vasopressin or oxytocin. Functionally, optogenetic stimulation of these neurons promotes the activation of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes, as well as a rise in systolic blood pressure. When these neurons are optogenetically inhibited, the activity of these neuroendocrine axes are suppressed and anxiety-like behavior in the elevated plus maze is dampened. Collectively, these studies implicate this neuronal population in the integration and coordination of the physiological responses to stress and may therefore serve as a potential target for therapeutic intervention for stress-related pathology.SIGNIFICANCE STATEMENT Chronic stress leads to an array of physiological responses that ultimately rouse psychological, cardiovascular, and metabolic impairments. As a consequence, there is an urgent need for the development of novel therapeutic approaches to prevent or dampen deleterious aspects of "stress." While the renin-angiotensin system has received some attention in this regard, the neural mechanisms by which this endocrine system may impact stress-related pathologies and consequently serve as targets for therapeutic intervention are not clear. The present studies provide substantial insight in this regard. That is, they reveal that a distinct population of angiotensin-sensitive neurons is integral to the coordination of stress responses. The implication is that this neuronal phenotype may serve as a target for stress-related disease.

Using 3-Dimensional Modeling to Customize Titanium Plates for Repair of Chest Wall Trauma.

BACKGROUND: Open reduction and internal fixation of rib fractures is recommended to decrease mortality, shorten the duration of mechanical ventilation, and lower hospital length of stay. Prosthetic titanium plates are frequently used to repair chest wall trauma, and are typically contoured to the patient's anatomy at the time of implant in the operating room. We describe the use of 3-dimensional (3D) digitally corrected rapid prototyping to generate a model of a patient's skeletal anatomy for the purposes of preoperative customization of standard titanium plates for fixation of rib fractures. METHODS: A computed tomography imaging Digital Imaging and Communication in Medicine data set was segmented. Rib fractures were virtually realigned using the mirrored normal anatomy as a guide. The model was printed and used to customize titanium rib fixation plates prior to the procedure. RESULTS: Preoperative shaping of 5 titanium plates using the final 3D model required a total of 5.65 minutes. Surgical fixation of 4 of the patient's 5 fractures was accomplished using the titanium plates that were preoperatively shaped using our 3D model. DISCUSSION: We demonstrate successful use of a digitally rendered model to preoperatively customize standard titanium rib fixation plates. Compared with intraoperative contouring of rib fixation plates, we believe that this approach facilitates repair of complex rib fractures, saving time in the operating room. We believe this technique can improve the accuracy of reductions, increase the ease and efficiency of these procedures, and afford benefits in reducing surgical stress on patients who have already suffered significant trauma.

Ischemia-responsive protein 94 is a key mediator of ischemic neuronal injury-induced microglial activation.

Neuroinflammation, especially activation of microglia, the key immune cells in the brain, has been proposed to contribute to the pathogenesis of ischemic stroke. However, the dynamics and the potential mediators of microglial activation following ischemic neuronal injury are not well understood. In this study, using oxygen/glucose deprivation and reoxygenation with neuronal and microglial cell cultures as an in vitro model of ischemic neuronal injury, we set out to identify neuronal factors released from injured neurons that are capable of inducing microglial activation. Conditioned media (CM) from hippocampal and cortical neurons exposed to oxygen/glucose deprivation and reoxygenation induced significant activation of microglial cells as well as primary microglia, evidenced by up-regulation of inducible nitric oxide synthase, increased production of nitrite and reactive oxygen species, and increased expression of microglial markers. Mechanistically, neuronal ischemia-responsive protein 94 (Irp94) was a key contributor to microglial activation since significant increase in Irp94 was detected in the neuronal CM following ischemic insult and immunodepletion of Irp94 rendered ischemic neuronal CM ineffective in inducing microglial activation. Ischemic insult-augmented oxidative stress was a major facilitator of neuronal Irp94 release, and pharmacological inhibition of NADPH oxidase significantly reduced the ischemic injury-induced neuronal reactive oxygen species production and Irp94 release. Taken together, these results indicate that neuronal Irp94 may play a pivotal role in the propagation of ischemic neuronal damage. Continued studies may help identify Irp94 and/or related proteins as potential therapeutic targets and/or diagnostic/prognostic biomarkers for managing ischemia-associated brain disorders.

Angiotensin type 1a receptors in the paraventricular nucleus of the hypothalamus control cardiovascular reactivity and anxiety-like behavior in male mice.

This study tested the hypothesis that deletion of angiotensin type 1a receptors (AT1a) from the paraventricular nucleus of hypothalamus (PVN) attenuates anxiety-like behavior, hypothalamic-pituitary-adrenal (HPA) axis activity, and cardiovascular reactivity. We used the Cre/LoxP system to generate male mice with AT1a specifically deleted from the PVN. Deletion of the AT1a from the PVN reduced anxiety-like behavior as indicated by increased time spent in the open arms of the elevated plus maze. In contrast, PVN AT1a deletion had no effect on HPA axis activation subsequent to an acute restraint challenge but did reduce hypothalamic mRNA expression for corticotropin-releasing hormone (CRH). To determine whether PVN AT1a deletion inhibits cardiovascular reactivity, we measured systolic blood pressure, heart rate, and heart rate variability (HRV) using telemetry and found that PVN AT1a deletion attenuated restraint-induced elevations in systolic blood pressure and elicited changes in HRV indicative of reduced sympathetic nervous activity. Consistent with the decreased HRV, PVN AT1a deletion also decreased adrenal weight, suggestive of decreased adrenal sympathetic outflow. Interestingly, the altered stress responsivity of mice with AT1a deleted from the PVN was associated with decreased hypothalamic microglia and proinflammatory cytokine expression. Collectively, these results suggest that deletion of AT1a from the PVN attenuates anxiety, CRH gene transcription, and cardiovascular reactivity and reduced brain inflammation may contribute to these effects.

Off-the-shelf percutaneous deep vein arterialization for no-option chronic limb-threatening ischemia related to Buerger disease.

Percutaneous deep venous arterialization (pDVA) is an important technique in the pursuit of limb salvage for a certain high-risk subset of patients with chronic limb-threatening ischemia (CLTI) considered to have "no option" owing to the lack of tibial or pedal targets for revascularization. pDVA seeks to establish an arteriovenous connection at the level of the tibial vessels, in addition to tibial and/or pedal venoplasty, to provide a pathway for arterial perfusion via the tibial and/or plantar venous system. A commercial system for pDVA exists; however, it is not yet approved by the U.S. Food and Drug Administration. In the present report, we detail a method of pDVA that uses commercially available devices for a patient with no-option CLTI related to Buerger disease.

A descriptive analysis of the Canadian prehospital and transport transfusion (CAN-PATT) network.

Objective: Out-of-hospital blood transfusion (OHBT) is becoming increasingly common across the prehospital environment, yet there is significant variability in OHBT practices. The Canadian Prehospital and Transport Transfusion (CAN-PATT) network was established to collaborate, standardize, and evaluate the effectiveness of out-of-hospital blood transfusion (OHBT) across Canada. The objectives of this study are to describe the setting and organizational characteristics of CAN-PATT member organizations and to provide a cross-sectional examination of the current OHBT practices of CAN-PATT organizations. Methods: This was a cross-sectional examination of all six critical care transport organizations that are involved in CAN-PATT network. Surveys were sent to identified leads from each organization. The survey focused on three main areas of interest: 1) critical care transport organizational service and coverage, 2) provider, and crew configurations, and 3) OHBT transfusion practices. Results: All six surveys were completed and returned. There are a total of 30 critical care transport bases (19 rotor-wing, 20 fixed-wing and 6 land) across Canada and 11 bases have a blood-on-board program. Crew configurations very between organizations as either dual paramedic or paramedic/nurse teams. Median transport times range from 30 to 46 minutes for rotor-wing assets and 64 to 90 minutes for fixed-wing assets. Half of the CAN-PATT organizations started their out-of-hospital blood transfusion programs within the last three years. Most organizations carry at least two units of O-negative, K-negative red blood cells and some organizations also carry group A thawed plasma, fibrinogen concentrate and/or prothrombin complex concentrate. All organizations advocate for early administration of tranexamic acid for injured patients suspected of bleeding. All organizations return un-transfused blood components to their local transfusion medicine laboratory within a predefined timeframe to reduce wastage. Conclusions: Variations in OHBT practices were identified and we have suggested considerations for standardization of transfusion practices and patient care as it relates to OHBT. This standardization will also enable a robust means of data collection to study and optimize outcomes of patients receiving OHBT. A fulsome description of the participating organizations within CAN-PATT should enhance interpretation of future OHBT studies that will be conducted by this network.

Development of a national out-of-hospital transfusion protocol: a modified RAND Delphi study.

BACKGROUND: Early resuscitation with blood components or products is emerging as best practice in selected patients with trauma and medical patients; as a result, out-of-hospital transfusion (OHT) programs are being developed based on limited and often conflicting evidence. This study aimed to provide guidance to Canadian critical care transport organizations on the development of OHT protocols. METHODS: The study period was July 2021 to June 2022. We used a modified RAND Delphi process to achieve consensus on statements created by the study team guiding various aspects of OHT in the context of critical care transport. Purposive sampling ensured representative distribution of participants in regard to geography and relevant clinical specialties. We conducted 2 written survey Delphi rounds, followed by a virtual panel discussion (round 3). Consensus was defined as a median score of at least 6 on a Likert scale ranging from 1 ("Definitely should not include") to 7 ("Definitely should include"). Statements that did not achieve consensus in the first 2 rounds were discussed and voted on during the panel discussion. RESULTS: Seventeen subject experts participated in the study, all of whom completed the 3 Delphi rounds. After the study process was completed, a total of 39 statements were agreed on, covering the following domains: general oversight and clinical governance, storage and transport of blood components and products, initiation of OHT, types of blood components and products, delivery and monitoring of OHT, indications for and use of hemostatic adjuncts, and resuscitation targets of OHT. INTERPRETATION: This expert consensus document provides guidance on OHT best practices. The consensus statements should support efficient and safe OHT in national and international critical care transport programs.

A Novel Organ-Specific Approach to Selectively Target Sensory Afferents Innervating the Aortic Arch.

The brain maintains cardiovascular homeostasis, in part, via the arterial baroreflex which senses changes in blood pressure (BP) at the level of the aortic arch. Sensory afferents innervating the aortic arch employ baroreceptors to convert stretch exerted on the arterial wall into action potentials carried by the vagus nerve to second order neurons residing within the nucleus of the solitary tract (NTS). Although the baroreflex was described more than 80 years ago, the specific molecular, structural, and functional phenotype of the baroreceptors remain uncharacterized. This is due to the lack of tools that provide the genetic and target organ specificity that is required to selectively characterize baroreceptor afferents. Here, we use a novel approach to selectively target baroreceptors. Male mice on a C57BL/6J background were anesthetized with isoflurane, intubated, and artificially ventilated. Following sternotomy, the aortic arch was exposed, and a retrograde adeno-associated virus was applied to the aortic arch to direct the expression of channelrhoropsin-2 (ChR2) and/or tdTomato (tdTom) to sensory afferents presumably functioning as baroreceptors. Consistent with the structural characteristics of arterial baroreceptors, robust tdTom expression was observed in nerve endings surrounding the aortic arch, within the fibers of the aortic depressor and vagus nerves, cell bodies of the nodose ganglia (NDG), and neural projections to the caudal NTS (cNTS). Additionally, the tdTom labeled cell bodies within the NDG also expressed mRNAs coding for the mechanically gated ion channels, PIEZO-1 and PIEZO-2. In vitro electrophysiology revealed that pulses of blue light evoked excitatory post-synaptic currents in a subset of neurons within the cNTS, suggesting a functional connection between the labeled aortic arch sensory afferents and second order neurons. Finally, the in vivo optogenetic stimulation of the cell bodies of the baroreceptor expressing afferents in the NDG produced robust depressor responses. Together, these results establish a novel approach for selectively targeting sensory neurons innervating the aortic arch. This approach may be used to investigate arterial baroreceptors structurally and functionally, and to assess their role in the etiology or reversal of cardiovascular disease.