Centimetre-scale perovskite solar cells with fill factors of more than 86 per cent.

Owing to rapid development in their efficiency1 and stability2, perovskite solar cells are at the forefront of emerging photovoltaic technologies. State-of-the-art cells exhibit voltage losses3-8 approaching the theoretical minimum and near-unity internal quantum efficiency9-13, but conversion efficiencies are limited by the fill factor (<83%, below the Shockley-Queisser limit of approximately 90%). This limitation results from non-ideal charge transport between the perovskite absorber and the cell's electrodes5,8,13-16. Reducing the electrical series resistance of charge transport layers is therefore crucial for improving efficiency. Here we introduce a reverse-doping process to fabricate nitrogen-doped titanium oxide electron transport layers with outstanding charge transport performance. By incorporating this charge transport material into perovskite solar cells, we demonstrate 1-cm2 cells with fill factors of >86%, and an average fill factor of 85.3%. We also report a certified steady-state efficiency of 22.6% for a 1-cm2 cell (23.33% ± 0.58% from a reverse current-voltage scan).

The geometric evolution of aortic dissections: Predicting surgical success using fluctuations in integrated Gaussian curvature.

Clinical imaging modalities are a mainstay of modern disease management, but the full utilization of imaging-based data remains elusive. Aortic disease is defined by anatomic scalars quantifying aortic size, even though aortic disease progression initiates complex shape changes. We present an imaging-based geometric descriptor, inspired by fundamental ideas from topology and soft-matter physics that captures dynamic shape evolution. The aorta is reduced to a two-dimensional mathematical surface in space whose geometry is fully characterized by the local principal curvatures. Disease causes deviation from the smooth bent cylindrical shape of normal aortas, leading to a family of highly heterogeneous surfaces of varying shapes and sizes. To deconvolute changes in shape from size, the shape is characterized using integrated Gaussian curvature or total curvature. The fluctuation in total curvature (δK) across aortic surfaces captures heterogeneous morphologic evolution by characterizing local shape changes. We discover that aortic morphology evolves with a power-law defined behavior with rapidly increasing δK forming the hallmark of aortic disease. Divergent δK is seen for highly diseased aortas indicative of impending topologic catastrophe or aortic rupture. We also show that aortic size (surface area or enclosed aortic volume) scales as a generalized cylinder for all shapes. Classification accuracy for predicting aortic disease state (normal, diseased with successful surgery, and diseased with failed surgical outcomes) is 92.8±1.7%. The analysis of δK can be applied on any three-dimensional geometric structure and thus may be extended to other clinical problems of characterizing disease through captured anatomic changes.

Reconfigurable Resistive Switching Memory for Telegraph Code Sensing and Recognizing Reservoir Computing Systems.

Reservoir computing (RC) system is based upon the reservoir layer, which non-linearly transforms input signals into high-dimensional states, facilitating simple training in the readout layer-a linear neural network. These layers require different types of devices-the former demonstrated as diffusive memristors and the latter prepared as drift memristors. The integration of these components can increase the structural complexity of RC system. Here, a reconfigurable resistive switching memory (RSM) capable of implementing both diffusive and drift dynamics is demonstrated. This reconfigurability is achieved by preparing a medium with a 3D ion transport channel (ITC), enabling precise control of the metal filament that determines memristor operation. The 3D ITC-RSM operates in a volatile threshold switching (TS) mode under a weak electric field and exhibits short-term dynamics that are confirmed to be applicable as reservoir elements in RC systems. Meanwhile, the 3D ITC-RSM operates in a non-volatile bipolar switching (BS) mode under a strong electric field, and the conductance modulation metrics forming the basis of synaptic weight update are validated, which can be utilized as readout elements in the readout layer. Finally, an RC system is designed for the application of reconfigurable 3D ITC-RSM, and performs real-time recognition on Morse code datasets.

Polygenic risk score informed clinical model for improving abdominal aortic aneurysm screening.

INTRODUCTION: Abdominal aortic aneurysm (AAA) is a complex disease with environmental and genetic risk factors. Polygenic risk scores (PRS) based on disease-specific risk-associated single nucleotide variants (SNVs) have demonstrated effectiveness in stratifying individual-level disease risk for cardiovascular diseases. This prospective cohort study assessed associations of PRS of AAA (PRSAAA) with risk of incident AAA, analyzed the effectiveness of a combined clinical-genetic risk model, and explored the clinical utility of the model in identifying high-risk individuals for AAA screening. METHODS: PRSAAA was calculated using 911,440 SNVs and PRSCAD was calculated using 2,324,683 SNVs derived from mixed ancestry genome wide association studies. The UK Biobank was used as the study cohort. All individuals with complete genetic data available and no diagnosis of AAA at time of recruitment were included in the analysis and followed prospectively to assess for incident AAA. A PRS informed clinical model, Prob-AAA, was developed using clinically significant variables and PRSAAA. RESULTS: 481,105 individuals were included in the analysis with 2,668 incident AAA cases. Incident AAA increased from 0.30% to 0.93% between the lowest and highest decile of PRSAAA; similarly, severe AAA, requiring surgery and/or presenting with rupture, increased from 23% to 39% of incident AAA cases across deciles. PRSAAA was a predictor of incident AAA diagnosis (HR 2.06 [1.70 - 2.48]) independent of other clinical risk factors including male sex, older age, and smoking history. Prob-AAA was an independent predictor of incident AAA (HR 1.92 [1.69 - 2.20]), and identified 9.6% of cases of incident AAA compared to only 4.2% by PRSAAA. Current screening guidelines captured 5.7% of the overall cohort, with an incident AAA rate of approximately 3.2%. Amongst males not included by current guidelines, Prob-AAA identified an additional cohort, approximately 2% of the overall cohort, with a similar rate of incident AAA. CONCLUSIONS: Prob-AAA, a PRS informed clinical model for AAA, improved upon the predictive power of current, clinical risk factor informed, screening guidelines for AAA.

Revascularizations and limb outcomes of hospitalized patients with diabetic peripheral arterial disease in the contemporary era.

BACKGROUND: Concomitant diabetes mellitus and peripheral artery disease (PAD) is a complex disease process. This retrospective analysis of the National Inpatient Sample sought to understand trends in limb outcomes of this unique and prevalent cohort of patients. METHODS: The National Inpatient Sample was queried between 2003 and 2017 for hospitalizations of patients with both type 2 diabetes mellitus and PAD. Trends in hospitalizations, limb outcomes, vascular interventions, and costs were analyzed. RESULTS: There were 10,303,673 hospitalizations of patients with concomitant diabetes mellitus and PAD that were identified between 2003 and 2017. The prevalence of hospitalizations associated with this disease process increased from 1644 to 3228 per 100,000 hospitalizations, a 96.4% increase. This included an increase of 288 to 587 per 100,000 hospitalizations of patients aged 18 to 49 years old, which was accompanied by a 10.8% increase in minor amputations. Nontraumatic lower extremity amputations decreased overall. Black and Hispanic ethnicity were associated with an increased risk for amputation, along with Medicaid insurance and lower income quartile. Inpatient endovascular revascularization has increased over time with an associated decrease in open revascularization procedures. Amputation-related hospital costs significantly increased from $6.6 billion in 2003 to $14.8 billion in 2017. CONCLUSIONS: An alarming increase of disease prevalence, negative in-hospital limb outcomes, and costs are seen in the current era in this analysis of patients with concurrent diabetes and PAD.

The effectiveness of oxytocin in the treatment of stimulant use disorders: a systematic review.

OBJECTIVES: The purpose of this review is to examine human study evidence on the effectiveness of oxytocin in this patient population. Despite stimulant use disorder being a major public health concern, there are no validated pharmacological treatments. Psychosocial interventions show limited effectiveness especially in the more severe cases of stimulant use disorder, whereas animal models suggest that oxytocin may be a useful treatment. METHODS: A literature search using Medline, Embase, and PsychInfo was undertaken. Search results were subsequently imported into Covidence to identify relevant studies. RESULTS: Six studies were included in this review, two of which were pilot studies. Although oxytocin was well tolerated across studies, no study showed a statistically significant reduction in reported cocaine use or cravings. One study suggested oxytocin increased the desire to use cocaine, although the population of participants should be taken into consideration. In contrast, one study showed a trend towards reduced self-reported cocaine use. CONCLUSION: Available research does not support the use of oxytocin in the management of stimulant use disorder; however, included studies are small in sample size and limited in number. There were several noteworthy findings unrelated to this review's primary and secondary outcomes, which are of interest and warrant further research. We provide suggestions for future studies in this area of research. Considering the limited data available at this time, further studies are required before any definitive conclusions can be made regarding the use of oxytocin in stimulant use disorder management.

Effects of Auricular Acupressure on Hip Flexibility and Pain in Taekwondo Participants: Randomized Controlled Trial.

BACKGROUND: In sports, hip flexibility is essential to reduce injuries and improve performance. AIM: This study aimed to examine the effects of auricular acupressure on hip flexibility and pain in Taekwondo participants. METHOD: This randomized controlled trial was performed in the Republic of Korea from January 2021 to August 2021. The Numeric Rating Scale for Pain and Hip Flexibility was used. Twenty-one participants received auricular pressure once weekly for six weeks, while 17 participants did not receive any intervention. Auricular acupressure was applied to the hip (AH13), Shinmun, and auricular acupressure points associated with the pain areas reported by the participants. RESULTS: Auricular acupressure improved hip flexibility (t = 2.67, p = .011) and back pain (t = 2.11, p = .043). The mean difference in post-pretest hip flexibility in the experimental group was 16.24 degrees (±13.63), whereas that in the control group was 4.77 degrees (±15.07). The mean difference in the experimental group's pre-post-test scores of back pain was 1.24 (±2.64), whereas that in the control group was 0.18 (±1.41). CONCLUSIONS: The results of this study showed that auricular acupressure could be used to treat pain and improve hip flexibility.

Perioperative outcomes for carotid revascularization on asymptomatic dialysis-dependent patients meet Society for Vascular Society guidelines.

OBJECTIVE: The current Society for Vascular Surgery practice guidelines recommend carotid revascularization for asymptomatic disease in patients with at least a 3-year life expectancy and stenosis >60% when the expected perioperative stroke and death rate is <3%. Based on this recommendation, it was previously determined that asymptomatic patients who require dialysis would not meet the perioperative stroke and death thresholds nor the long-term survival benchmarks to justify carotid surgery. To determine whether carotid surgery for patients requiring dialysis is appropriate, the present study compared the perioperative outcomes after carotid revascularization for dialysis-dependent patients relative to nondialysis patients in a contemporary, national cohort. METHODS: The targeted vascular module from the American College of Surgeons National Surgical Quality Improvement Program was queried to identify patients who undergone carotid endarterectomy or carotid artery stenting for asymptomatic carotid disease from 2011 to 2018. The cohort was categorized as requiring or not requiring dialysis. The primary 30-day outcomes included mortality and the composite of stroke/death and stroke/death/myocardial infarction (MI). Univariate analyses were performed using the Fisher exact test and Wilcoxon rank sum test. Multivariable analyses were used to assess the independent associations of the estimated glomerular filtration rate and dialysis dependence with the stroke/death rate. RESULTS: A total of 17,579 patients met the inclusion criteria. Of these patients, 226 (1.3%) required dialysis at revascularization. No difference was found in the degree of severe stenosis (80%-99%) demonstrated by 69% of the dialysis cohort and 72% of the nondialysis cohort (P = .9). Of the dialysis and nondialysis cohorts, 5% and 3.6% underwent carotid artery stenting (P = .3). The dialysis-dependent patients were younger (68 vs 71 years; P < .001) and were more likely to have insulin-dependent diabetes (47% vs 12%; P < .001), congestive heart failure (8.4% vs 1.4%; P < .001), and severe chronic obstructive pulmonary disease (15% vs 10%; P = .03). In the dialysis and nondialysis cohort, 2 (0.9%) and 88 (0.5%) patients died (P = .3); 4 (1.8%) and 247 (1.4%) experienced strokes (P = .6); and 3 (1.3%) and 185 (1.1%) patients experienced MI (P = .5), respectively. The composite outcomes of stroke/death and stroke/death/MI was 2.2% (n = 5) and 1.8% (n = 319; P = .6) and 3.5% (n = 8) and 2.8% (n = 479; P = .4) in the dialysis and nondialysis cohorts, respectively. After multivariable analysis, neither the estimated glomerular filtration rate (adjusted odds ratio, 1.0; 95% confidence interval, 1.00-1.01; P = .26) nor dialysis dependence (adjusted odds ratio, 0.21; 95% confidence interval, 0.03-1.57; P = .13) was independently associated with the composite outcome of stroke/death. CONCLUSIONS: The 30-day carotid revascularization outcomes for asymptomatic disease in dialysis-dependent patients met the Society for Vascular Surgery guidelines in this national cohort and might be better than previously surmised. Hence, vascular surgeons could consider carotid revascularization for select dialysis-dependent patients with the appropriate expected longevity and perioperative risk.

Gaussian Surface Curvature Mapping Indicating High Risk Type B Thoracic Aortic Dissections.

BACKGROUND: Identifying fragile aortas that are more likely to lead to adverse clinical outcomes would provide surgeons with a better sense of how to balance the risks of surgical versus medical management in patients with type B dissections. We examine the progression of a type B dissection into a type A dissection in a patient and analyze changes in the Gaussian surface curvature distribution, as well as the response of the stress distribution at the lesser curve in response to pressurization. We hypothesize that examining the Gaussian curvature will provide us with a link between aortic surface geometry and the stress distribution, which is crucial to understanding the process driving aortic dissection. METHODS: Computed tomography scans of a patient before and after the type A dissection are obtained. These are segmented in Simpleware ScanIP. Centerline curvatures are calculated on segmented models in ScanIP. Models are then pressurized in the finite element analysis software Abaqus. The Gaussian curvature is calculated by exporting segmentations into the computational program Matlab and applying a modified previously published algorithm. RESULTS: The centerlines generated in ScanIP fail to capture the change in the acuity of the lesser curve before and after the type A dissection. Instead, Gaussian curvature analysis shows that the curvature distribution before the type A dissection is much wider compared with the distribution after the type A dissection. In addition, analyzing the stress distribution in response to pressurization reveals that before the type A dissection there is a large divergence in the principal stress vectors at the lesser curve but this transitions to a more uniform hoop stress after the type A dissection. CONCLUSIONS: Our analysis demonstrates that Gaussian surface curvature analysis captures changes in aortic geometry that are otherwise silent in centerline curvature analysis. Here, we show that as the aorta develops a type A dissection it is able to more smoothly handle the hoop stress at the lesser curve compared with the stress focusing seen in the before type A geometry. We propose that the geometric focusing before type A creates a higher energy stress state, which is relaxed on retrograde dissection. Thus, Gaussian curvature analysis may provide a window to capture underlying geometric instability in type B dissections.

Fusion rates for conservative and surgical management of type II odontoid fractures and its impact.

BACKGROUND: Type II odontoid fractures are known to have low fusion rates following conservative management with a hard collar. However, most patients are elderly with comorbidities and are not fit for surgery. The present study identified the rates of bony fusion, complications, and clinical outcomes following conservative management of type II odontoid fractures. METHODS: We included consecutive patients referred with a suspected odontoid fracture to a Major Trauma Centre in the UK between March 2015 and December 2017. Data including patient demographics, fracture management, complications and outcomes. Bony fusion was assessed by two neurosurgeons and one neuroradiologists. Results were analysed with simple statistics and chi-squared test. RESULTS: 102 patients were included in the study (mean age = 80.4 ± 15.3). 10 (9.8%) were managed surgically and 92 (90.2%) were managed conservatively with a hard collar, for a mean of 87 days. Patients were followed up for a mean of 28.1 months (range 1-855 days) until discharge. 37% developed collar complications, namely pain, stiffness and non-tolerance. Bony union was achieved in 37.3% of patients treated with a hard collar (versus 80% in the surgical group, p = 0.0096). Increasing age was an independent risk factor for non-union (p < 0.001). Of the patients without bony union, none reported symptoms, and 90% were discharged without a collar. CONCLUSION: The management of type II odontoid fractures are difficult in an elderly, co-morbid population. With conservative management fusion rates are low, and collar complications are not insignificant. However, outcomes are good regardless of union.

Aortic Remodeling and Clinical Outcomes Following Thoracic Endovascular Aortic Repair for Blunt Thoracic Aortic Injury.

BACKGROUND: There is currently limited data assessing the long-term consequences of thoracic endovascular aortic repair (TEVAR) in otherwise healthy aortic segments remote from the site of endograft coverage. The aim of this study is to retrospectively evaluate aortic remodeling and long-term outcomes of blunt thoracic aortic injury (BTAI) patients treated with TEVAR. Our hypothesis is that significant changes to the aorta proximal to the graft-covered segment are suspected following TEVAR. METHODS: An institutional review board-approved retrospective review of patients who underwent TEVAR for BTAI at a level I trauma center from 2004 to 2018 was performed. Forty-six patients were identified and of these, 32 patients with high-resolution computed tomographic angiography imaging follow-up were included in the study. Computed tomographic angiography measurements of aortic dimensions and branch vessels proximal, distal, and adjacent to the stent grafted segment were recorded preprocedure and postprocedure and analyzed. Primary device-related outcomes such as birdbeaking, mural thrombus, stent migration, and persistent endoleak were assessed. Patient outcomes including mortality, graft-related morbidity, and need for secondary interventions were also analyzed. RESULTS: Mean follow-up of the selected patients in the study was 1.52 y (range, 0.06-8.0 y). Following TEVAR, the ascending aortic length increased significantly (mean 5.7 ± 4.6 mm, P < 0.001). The mean diameters of the ascending aorta (1.5 ± 1.5, P < 0.001 mm), the midaortic arch (1.3 ± 1.7 mm, P < 0.001), and proximal and the distal endograft landing zones (1.9 ± 2.1 mm and 2.2 ± 1.6 mm, respectively, P < 0.001) also increased significantly following TEVAR. Clinically relevant device-related outcomes occurred with the presence of endograft infolding and subsequent development of endograft mural thrombus (P < 0.001). The need for secondary intervention following TEVAR for BTAI was associated with endograft mural thrombus (P < 0.05). CONCLUSIONS: TEVAR for BTAI causes significant geometric changes in the aorta proximal to the stented grafted segment of the aorta. Direct consequences of the graft at the stented segment includes mural thrombus development within the endograft which was associated with the need for secondary intervention. Although clinical significance is yet to be determined, post-TEVAR changes in aortic architecture warrant continued aortic surveillance following BTAI.

Trends and Determinants of Readmissions to Another Facility After Endovascular Aortic Repair.

BACKGROUND: Endovascular aneurysm repair (EVAR) has become the procedure of choice for abdominal aortic aneurysms (AAAs). It has been previously reported that significant percentage of patients were being readmitted to another hospital after complications after EVAR. We aimed to evaluate trends and clinical predictors of readmission to another (secondary) hospital after index EVAR. METHODS: The Nationwide Readmissions Database (NRD) was queried for all 30-day readmissions after an index EVAR procedure from 2012 to 2014. Readmission diagnosis, patient demographics, and hospital characteristics were collected regarding those patients who were admitted to another care facility after EVAR. Univariate analysis and multivariable logistic regression model was used to identify predictors for readmission to a different hospital. RESULTS: Between 2012 and 2014, 3,215 patients were readmitted to another hospital within 30 days of their index EVAR constituting 22.8% of a total 14,073 readmissions during that time period. Comorbidities of patients examined were similar between those patients readmitted to the primary hospital versus the secondary hospital except for the incidence of hypothyroidism (P < 0.001). Higher proportion of patients admitted to a different hospital had Medicare and Medicaid insurance (P < 0.047). In addition, higher proportion of patients readmitted to secondary hospitals had EVAR performed at smaller (<100 beds) hospitals (P = 0.002). Univariate analysis demonstrated that patients readmitted to another hospital were slightly older and had higher index length of stay and higher index hospital cost after EVAR (P < 0.001). In a multivariate model, index EVAR at a small hospital (odds ratio [OR]: 1.7) and the diagnosis of hypothyroidism (OR: 1.54) were independent determinants of readmission to another care facility. CONCLUSIONS: Significant proportion of patients is being readmitted elsewhere after elective EVAR adding complexity to the determination of appropriate healthcare resource allocation. In our study, index EVAR at a small hospital (<100 beds) and pre-existing medical comorbidity of hypothyroidism were significant predictors for unanticipated readmission to a different hospital.

Decreased mortality with local versus general anesthesia in endovascular aneurysm repair for ruptured abdominal aortic aneurysm in the Vascular Quality Initiative database.

BACKGROUND: Endovascular aneurysm repair (EVAR) is an accepted approach for patients presenting with ruptured abdominal aortic aneurysm (rAAA) and suitable anatomy. The effect of anesthesia modality on mortality outcomes in rAAA has not been well described. Using the Vascular Quality Initiative database, this study compares local anesthesia (LA) vs general anesthesia (GA) in EVAR for rAAA. METHODS: The Vascular Quality Initiative database was queried for patients presenting with rAAA managed with open surgical repair, EVAR under LA (rEVAR-LA), and EVAR under GA (rEVAR-GA) between 2003 and 2017. Patients were observed until the earlier end point of either death or 1-year follow-up. Kaplan-Meier event rates are presented at 30 days and 1 year. Cox proportional hazards regression was used to model risk of death, with adjustment for demographic and clinical factors. Additional multivariate Cox hazards analyses were used to assess effect modifiers for 1-year mortality for the different repair methods. RESULTS: A total of 3330 patients (77.4% male) met the inclusion criteria (1594 [47.9%] open surgical repair, 226 [6.8%] rEVAR-LA, and 1510 [45.3%] rEVAR-GA). Patients treated with rEVAR-LA compared with rEVAR-GA had decreased intraoperative time, number of intraoperative blood transfusions, intraoperative crystalloid administration, intensive care unit length of stay, and postoperative pulmonary complications. Mortality rates with rEVAR-LA were lower compared with rEVAR-GA at 30 days (15.5% vs 23.3%; adjusted hazard ratio [AHR], 0.70; 95% confidence interval [CI], 0.49-0.99; P = .04) and at 1 year (22.5% vs 32.3%; AHR, 0.71; 95% CI, 0.53-0.96; P = .02). Patients undergoing EVAR who were <75 years old and those without preoperative hypotension had the greatest survival benefit from LA compared with GA (both factors: AHR, 0.14 [95% CI, 0.03-0.57]; single factor: AHR, 0.57 [95% CI, 0.36-0.91]). CONCLUSIONS: This study demonstrates that rEVAR-LA for rAAA may be a safe alternative to rEVAR-GA for certain patients, with lower morbidity and improved mortality. Further prospective study is warranted to confirm mortality benefit in rEVAR-LA for rAAA.

Unplanned 30-day readmissions after endovascular aneurysm repair: An analysis using the Nationwide Readmissions Database.

BACKGROUND: Endovascular aneurysm repair (EVAR) is the preferred method for addressing abdominal aortic aneurysms (AAAs), with proven reduction in perioperative morbidity and mortality. There are, however limited data examining the readmissions after EVAR that are associated with increased patient morbidity and cost. As EVAR use continues its dominance in the management of AAAs, it becomes imperative to identify and mitigate risk factors associated with unplanned hospital readmissions. METHODS: The Nationwide Readmissions Database (NRD) was queried for all 30-day readmissions after an index EVAR procedure from 2012 to 2014. Preoperative patient demographics, hospital characteristics, readmission diagnosis, and costs were compared between those who were and were not readmitted within 30 days of the index operation. Multivariable logistic regression was used to identify potential risk factors associated with unplanned readmissions within 30 days. RESULTS: We identified 120,646 patients who underwent an EVAR from 2012 to 2014 in the United States. The overall unplanned readmission rate during this period was 11.6% (n = 14,073) within 30 days of the index EVAR procedure. The readmission rate was the highest in 2012, with a rate of 12.3% (P = .02). Multivariate regression analysis showed that EVAR readmissions were significantly higher in patients who were of younger age (18 to 49 years) compared with other age groups (odds ratio [OR], 1.9-2.17; P < .001), female sex (OR, 1.367; P < .001), had Medicare (OR, 1.39) or Medicaid (OR, 1.25) insurance, or a combination of these. Underlying patient comorbidities significantly associated with readmissions included congestive heart failure (OR, 2.4), peripheral vascular disease (OR, 1.1), chronic pulmonary disease (OR, 1.2), cancer with no metastasis (OR, 1.5), metastatic cancer (OR, 2.2), renal failure (OR, 1.8), and diabetes (OR, 1.5). CONCLUSIONS: The trend in 30-day readmission rates after EVAR has decreased slightly since 2012, but overall rates are at 11.6%, which is not insubstantial. Patient factors strongly associated with hospital readmission were younger age and patient comorbidities, including congestive heart failure, concurrent cancer diagnosis, renal failure, and diabetes.

Outcomes and Cost Comparison of Percutaneous Endovascular Aortic Repair versus Endovascular Aortic Repair With Open Femoral Exposure.

BACKGROUND: The objective of this study was to assess cost differences between patients who underwent percutaneous endovascular aortic repair (PEVAR) and open surgical femoral exposure in elective endovascular aortic repair (EVAR) of abdominal aortic aneurysms. MATERIALS AND METHODS: An IRB-approved single center retrospective analysis of patients who underwent elective EVAR for abdominal aortic aneurysms from 2009 to 2016 was performed. One hundred patients were selected with 50 patients who underwent PEVAR and 50 patients who underwent open surgical femoral exposure. Patient demographics, procedural variables, and hospital outcomes were collected and compared. Primary outcomes assessed used in cost calculations included operating time (OR time), hospital length of stay (LOS), and intensive care unit stay (ICU LOS). Extrapolated cost differences were based on known, published cost multipliers for the primary outcomes observed. RESULTS: Patients undergoing PEVAR had significant reduction in mean OR time (113.9 min versus 144.9 min, P < 0.001), mean ICU LOS (19.7 h versus 28.9 h, P = 0.094), and overall LOS (28.3 h versus 33.1 h, P = 0.020). There was no statistically significant difference in access related complications, although there was a trend toward less complication rates with PEVAR (0% versus 5%, P = 0.056). Calculated cost of procedures based on mean ICU LOS, hospital LOS, and OR time, showed significant reduction in mean hospital costs with PEVAR ($16,628.5 versus $21,705.8, P < 0.001). Multiple linear regression analysis demonstrated an overall 23% cost reduction with PEVAR. CONCLUSIONS: Prior reports comparing PEVAR versus EVAR with open femoral exposures have shown improvement in overall patient time to ambulation and other hospital metrics such as LOS with PEVAR. There is, however, a paucity of overall cost comparison data regarding PEVAR. In this study, adoption of PEVAR was seen to significantly reduce OR times (19%) and overall hospital LOS (50%). The outcomes observed ultimately translated into significant reduction in hospital costs.

Postoperative venous thromboembolism and mortality in patients with pancreatic surgery.

BACKGROUND AND OBJECTIVES: Pancreatic cancer is strongly associated with thrombosis. We investigated early postoperative venous thromboembolism (PVTE) mortality among patients with pancreatic surgery and compared outcomes in adenocarcinoma pancreatic cancer (ACPC) to non-adenocarcinoma pancreatic neoplasm (NACPN). METHODS: We analyzed a prospectively collected database of patients who underwent pancreatic cancer or neoplasm-related surgery. As NACPN is underrepresented in other studies, we selected NACPN patients and a random sample of ACPC patients. PVTE was defined as VTE occurring within 3 months of surgical intervention. Statistical analysis was performed using Cox proportional hazards regression. RESULTS: A total of 441 pancreatic surgery patients were included, with 331 ACPC and 110 NACPN. Median follow-up was 449 days during which 90 (20.4%) patients developed VTE. PVTE occurred in 53 (12.0%) patients, including 41 (12.4%) ACPC patients and 12 (10.9%) NACPN patients. Those with PVTE had 60% higher mortality rate. A multivariable analysis found that PVTE is an independent predictor of increased mortality (HR Adj, 1.6; 95% CI, 1.1-2.2; P < .01). The mortality impact was not consistent between ACPC (HR, 3.2; 95% CI, 1.3-7.9) and NACPN groups (HR, 1.3; 95% CI, 0.9-1.8). CONCLUSIONS: Postoperative venous thromboembolism is an independent predictor of increased mortality in pancreatic surgery, specifically in adenocarcinoma pancreatic cancer surgery.

Explanting the Nellix Endovascular Aortic Sealing Endoprosthesis for Proximal Aortic Neck Failure.

Open conversion after endovascular aortic repair has inherent challenges particular to the device being explanted. The Nellix endograft is unlike any other device as it uses polymer filling of endobags within the aorto-iliac lumen to seal the abdominal aortic aneurysm (AAA) sac, a developing concept known as endovascular aneurysm sealing. Conversion to open repair of AAA treated with the Nellix endograft has rarely been discussed. Explants that have been previously reported were for graft infection. We present 2 Nellix graft explants that were required for device migration and subsequent development of a type IA endoleak. The technique and nuances observed during open conversion of this novel endograft for proximal aortic neck failure is described in this report.

Evolving Trends in Insurance Coverage of Vascular Surgery Patients in Academic Practice.

BACKGROUND: Insurance coverage of vascular surgery patients may differ from patients with less chronic surgical pathologies. The goal of this study is to identify trends in insurance status of vascular surgery patients over the last 10 years at a busy academic center. METHODS: All consecutive patient visits for a vascular procedure from 2006 to 2016 were retrospectively reviewed from a prospectively collected institutional database. Data points included insurance status, procedures performed, and date of admission. The insurance status was categorized as Medicare, Medicaid, and uninsured. Samples were divided between 2006-2009 and 2011-2016 for comparison. Unpaired t-test, chi-squared test, and regression analysis were used to determine significant trends over the study period. RESULTS: From 2006 to 2016, 6,007 vascular surgery procedures were performed. Procedure volume increased significantly from 1,309 to 4,698 between the 2 timeframes (P < 0.05), whereas the percentage of Medicaid and Medicare patients trended upward but did not achieve significance. There was a significant decrease in the percentage of uninsured patients between the cohorts (5.65% vs. 2.96%, P < 0.05). In 2012, 10.14% of patients were uninsured compared with 2.56% in 2016 (P < 0.05). CONCLUSIONS: Insurance status affects access to care and subsequent outcomes. In our busy academic center, insurance coverage for vascular surgery has significantly increased over the past decade. The number of Medicaid and Medicare patients has slowly increased, but a significant and continuing decline in uninsured patients was observed. Implementation of the Affordable Care Act during this time period may have played a role in providing coverage for patient needing vascular surgery.

Diagnostic workup and endovascular treatment of popliteal artery trauma.

Although management paradigms for certain arterial trauma, such as aortic injuries, have moved towards an endovascular approach, the application of endovascular techniques for the treatment of peripheral arterial injuries continues to be debated. In the realm of peripheral vascular trauma, popliteal arterial injuries remain a devastating condition with significant rates of limb loss. Expedient management is essential and surgical revascularization has been the gold standard. Initial clinical assessment of vascular injury is aided by readily available imaging techniques such as duplex ultrasonography and high resolution computed tomographic angiography. Conventional catheter based angiography, however, remain the gold standard in the determination of vascular injury. There are limited data examining the outcomes of endovascular techniques to address popliteal arterial injuries. In this review, we examine the imaging modalities and current approaches and data regarding endovascular techniques for the management popliteal arterial trauma.

Sex-dependent outcomes following elective endovascular aortic repair.

BACKGROUND: Evidence has shown that women derive less benefit from endovascular aortic repair (EVAR) in large part due to more challenging aortoiliac anatomy. This study sought to examine whether sex-dependent outcomes exist following elective EVAR cases. METHODS: An institutional retrospective review was performed on patients who underwent elective EVAR procedures between 2008 and 2014. Outcome data collected included procedural and hospital morbidity, mortality, and overall EVAR durability based on the incidence of unplanned graft-related secondary interventions (SIs) (e.g., open conversion, proximal or distal extensions, and coil embolizations). RESULTS: One hundred eighty-one patients (150 men, 31 women) met the study inclusion criteria. Median follow-up was 40.3 mo. Women had more challenging anatomy compared to men including smaller overall iliac diameters (6.8 mm versus 8.0 mm, P < 0.001) and more severe iliac angulation (77% moderate to severe versus 44%, P < 0.001). Women had increased risk of postoperative complications compared to men (41.9% versus 11.3%, P = 0.003). There was no perioperative mortality in our series of elective EVAR cases. Median 5-y survival following EVAR was 64.4% for men and 76.3% for women (P = 0.599). Late SI rates following EVAR was 10.5% with 16 (10.7%) men and 3 (9.7%) women needing interventions (P = 0.870). Overall durability of EVAR extrapolated as time to SIs was 91% at 2 y and 85% at 5 y. Factors predisposing SIs were iliac tortuosity (P = 0.046), aortic neck angle (P = 0.022), and endoleak at the follow-up (P = 0.030). CONCLUSIONS: In this study, immediate outcomes following EVAR were different between men and women, with women having increased rates of postoperative complications. Mortality and overall long-term durability of EVAR, however, were the same between sexes despite anatomical differences. EVAR durability was significantly dependent on the severity of iliac tortuosity, aortic neck angulation, and presence of endoleak at the follow-up.