The role of sealants for achieving anastomotic hemostasis in vascular surgery.

BACKGROUND: During vascular interventions, connections that link arteries, veins, or synthetic grafts, which are known as an 'anastomosis', may be necessary. Vascular anastomoses can bleed from the needle holes that result from the creation of the anastomoses. Various surgical options are available for achieving hemostasis, or the stopping of bleeding, including the application of sealants directly onto the bleeding vessels or tissues. Sealants are designed for use in vascular surgery as adjuncts when conventional interventions are ineffective and are applied directly by the surgeon to seal bleeding anastomoses. Despite the availability of several different types of sealants, the evidence for the clinical efficacy of these hemostatic adjuncts has not been definitively established in vascular surgery patients. OBJECTIVES: To evaluate the benefits and harms of sealants as adjuncts for achieving anastomotic site hemostasis in patients undergoing vascular surgery. SEARCH METHODS: The Cochrane Vascular Information Specialist conducted systematic searches of the following databases: the Cochrane Vascular Specialised Register via the Cochrane Register of Studies; the Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE via Ovid; Embase via Ovid ; and CINAHL via EBSCO. We also searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform for clinical trials. Reference lists of included trials and relevant reviews were also searched. The latest search date was 6 March 2023. SELECTION CRITERIA: We included randomized controlled trials that compared fibrin or synthetic sealant use with alternative interventions (e.g. manual compression, reversal of anticoagulation) for achieving anastomotic-site hemostasis in vascular surgery procedures. We included participants who underwent the creation of an anastomosis during vascular surgery. We excluded non-vascular surgery patients. DATA COLLECTION AND ANALYSIS: We have used standard Cochrane methods. Our primary outcomes were time to hemostasis, failure of hemostatic intervention, and intraoperative blood loss. Our secondary outcomes were operating time, death from bleeding complications up to 30 days, postoperative bleeding up to 30 days, unplanned return to the operating room for bleeding complications management up to 30 days, quality of life, and adverse events. We used GRADE to assess the certainty of evidence for each outcome. MAIN RESULTS: We found 24 randomized controlled trials that included a total of 2376 participants who met the inclusion criteria. All trials compared sealant use with standard care controls, including oxidized cellulose, gelatin sponge, and manual compression. All trials were at high risk of performance bias, detection bias, and other sources of bias. We downgraded the certainty of evidence for risk of bias concerns, inconsistency, imprecision and possible publication bias. Combining data on time to hemostasis showed that sealant use may reduce the mean time to hemostasis compared to control (mean difference (MD) -230.09 seconds, 95% confidence interval (CI) -329.24 to -130.94; P < 0.00001; 7 studies, 498 participants; low-certainty evidence). Combining data on failure of hemostatic intervention showed that sealant use may reduce the rate of failure compared to control, but the evidence is very uncertain (risk ratio (RR) 0.46, 95% CI 0.35 to 0.61; P < 0.00001; 17 studies, 2120 participants; very low-certainty evidence). We did not detect any clear differences between the sealant and control groups for intraoperative blood loss (MD -32.69 mL, 95% CI -96.21 to 30.83; P = 0.31; 3 studies, 266 participants; low-certainty evidence); operating time (MD -18.72 minutes, 95% CI -40.18 to 2.73; P = 0.09; 4 studies, 436 participants; low-certainty evidence); postoperative bleeding (RR 0.78, 95% CI 0.59 to 1.04; P = 0.09; 9 studies, 1216 participants; low-certainty evidence), or unplanned return to the operating room (RR 0.27, 95% CI 0.04 to 1.69; P = 0.16; 8 studies, 721 participants; low-certainty evidence). No studies reported death from bleeding or quality of life outcomes. AUTHORS' CONCLUSIONS: Based on meta-analysis of 24 trials with 2376 participants, our review demonstrated that sealant use for achieving anastomotic hemostasis in vascular surgery patients may result in reduced time to hemostasis, and may reduce rates of hemostatic intervention failure, although the evidence is very uncertain, when compared to standard controls. Our analysis showed there may be no differences in intraoperative blood loss, operating time, postoperative bleeding up to 30 days, and unplanned return to the operating room for bleeding complications up to 30 days. Deaths and quality of life could not be analyzed. Limitations include the risk of bias in all studies. Our review has demonstrated that using sealants may reduce the time required to achieve hemostasis and the rate of hemostatic failure. However, a significant risk of bias was identified in the included studies, and future trials are needed to provide unbiased data and address other considerations such as cost-effectiveness and adverse events with sealant use.

Ravulizumab facilitates reduced burden of vascular access, a major benefit in paediatric atypical haemolytic uraemic syndrome.

BACKGROUND: Atypical haemolytic uraemic syndrome (aHUS) is a rare thrombotic microangiopathy resulting from dysregulation of the alternative complement pathway, leading to multi-organ dysfunction and chronic kidney disease. Eculizumab is an anti-C5 monoclonal antibody therapy that has significantly improved aHUS disease control and patient outcomes, however it requires fortnightly intravenous dosing. This often necessitates long term central access and a high hospital attendance burden. Ravulizumab is a novel, next-generation anti-C5 monoclonal antibody engineered from eculizumab to reduce endosomal degradation of the antibody, increasing the dosing interval up to 8 weeks. CASE SERIES: In this retrospective case series we present the transition of three children with aHUS from eculizumab to ravulizumab from a single tertiary paediatric nephrology service. All patients underwent genomic and immunological work up for aHUS, with no cause found. After stabilisation with eculizumab, two patients developed macrovascular thrombotic complications associated with indwelling central vascular catheters, ultimately leading to central access failure. All patients were transitioned from eculizumab to ravulizumab without relapse of aHUS. One patient successfully underwent deceased donor kidney transplantation with ravulizumab for complement inhibition. All patients have transitioned to peripheral access for infusions given the reduced frequency of dosing, maintaining good control of aHUS for 2-4 years. CONCLUSION: Ravulizumab permits sufficiently reduced frequency of infusion to allow for administration by peripheral cannulation - removing the risks of long term central vascular access often required to deliver eculizumab to paediatric patients.

Quality by Design Considerations for Drop-on-Demand Point-of-Care Pharmaceutical Manufacturing of Precision Medicine.

Distributed and point-of-care (POC) manufacturing facilities enable an agile pharmaceutical production paradigm that can respond to localized needs, providing personalized and precision medicine. These capabilities are critical for narrow therapeutic index drugs and pediatric or geriatric dosing, among other specialized needs. Advanced additive manufacturing, three-dimensional (3D) printing, and drop-on-demand (DoD) dispensing technologies have begun to expand into pharmaceutical production. We employed a quality by design (QbD) approach to identify critical quality attributes (CQAs), critical material attributes (CMAs), and critical process parameters (CPPs) of a POC pharmaceutical manufacturing paradigm. This theoretical framework encompasses the production of active pharmaceutical ingredient (API) "inks" at a centralized facility, which are distributed to POC sites for DoD dispensing into/onto delivery vehicles (e.g., orodispersible films, capsules, single liquid dose vials). Focusing on the POC dispensing/dosing processes, QbD considerations and cause-and-effect analyses identified the dispensed API quantity and solid-state form (CQAs), as well as the nozzle diameter, system pressure channel, and number of drops dispensed (CPPs) for detailed investigation. Final assay quantification and content uniformity CQAs were measured from demonstrative levothyroxine sodium single-dose liquid vials of glycerin/water, meeting the standard acceptance values. Each POC facility is unlikely to maintain full quality control laboratory capabilities, requiring the development of appropriate atline or inline methods to ensure quality control. We developed control strategies, including atline ultraviolet-visible (UV-vis) verification of the API ink prior to dispensing, inline drop counting during dispensing, intermediate atline-dispensed volume checks, and offline batch confirmation by liquid chromatography-tandem mass spectrometry (LC-MS/MS) following production.

Percutaneous Balloon-Expandable Stent Implantation to Treat Transverse Aortic Arch Obstruction: Medium- to Long-Term Outcomes of a Retrospective Multicenter Study.

BACKGROUND: Transverse aortic arch obstruction is a challenging lesion for which stent implantation provides a potentially important alternate therapy. The objectives were to evaluate the technical, procedural, and medium-to-long-term clinical outcomes of percutaneous stent implantation of transverse aortic arch obstruction. METHODS: This is a retrospective, multicenter study of transverse aortic arch stent implantation. Univariable and multivariable analyses were performed. RESULTS: Index catheterization included 187 stent implants in 146 patients. The median age is 14.3 years (interquartile range, 9.3-19), weight is 53 kg (30-69), and follow-up is 53 months (12-120). The most common stent design was open cell (n=90, 48%). Stents overlapped 142 arch vessels (37 carotid arteries) in 118 (81%) cases. Technical and procedural success rates were 100% and 88%, respectively. Lower weight (P=0.018), body surface area (P=0.013), and minimum-to-descending aortic diameter ratio (P<0.001) were associated with higher baseline aortic gradient. The residual gradient was inversely associated with implant and final dilation diameters (P<0.001). The combined incidence of aortic injury and stent-related complications was 14%. There were no reports of abnormal brain scans or stroke. Blood pressure cuff gradient, echocardiographic arch velocity, and hypertension rates improved within 1-year follow-up with increased antihypertensive medication use. Reintervention was reported in 60 (41%) patients at a median of 84 (22-148) months to first reintervention. On multivariable logistic regression, residual aortic gradient >10 mm Hg was associated with increased odds of reintervention at all time points when controlling for each final dilation diameter, weight, and minimum-to-descending aortic diameter ratio. CONCLUSIONS: Transverse aortic arch stent implantation has high rates of technical, procedural, and medium-to-long-term clinical success. Aortic gradient >10 mm Hg is associated with increased odds of reintervention at 1-year and most recent follow-ups. Open cell stent design was frequently used for its advantages in conformability, perfusion of arch vessels, low fracture rate, and the ability to perform effective angioplasty of side cells.

Surgically repaired tetralogy of Fallot in the 7th decade: a late presentation of severe pulmonic regurgitation.

BACKGROUND: Surgically repaired tetralogy of Fallot (TOF) is a congenital heart disease with a cumulative survival rate of 72% in the 4th decade of life in longitudinal single-cohort studies. Debate surrounds conservative versus surgical management in adults with TOF once pulmonary regurgitation occurs. CASE PRESENTATION: A 73-year-old male with surgically corrected TOF presented with heart failure symptoms. He underwent ToF repair with a classic right Blalock-Taussig shunt at 2 years of age with transannular patching at 18 years of age. Echocardiography revealed elevated right ventricular systolic pressures, severe right ventricular dilatation, and pulmonary regurgitation. Our patient's new-onset right-sided heart failure was managed medically with diuresis. He received a new pulmonic valve via percutaneous approach on a later planned hospitalization with resolution of symptoms and improved tricuspid regurgitation. CONCLUSION: It is a class I recommendation for pulmonic valve intervention once greater than moderate PR occurs; however, medical optimization should take place first. Following adequate RV load optimization, our patient underwent successful transcatheter pulmonic valve implantation with resolution of symptoms and cessation of diuretic.

Kidney organoids reveal redundancy in viral entry pathways during ACE2-dependent SARS-CoV-2 infection.

With a high incidence of acute kidney injury among hospitalized COVID-19 patients, considerable attention has been focussed on whether SARS-CoV-2 specifically targets kidney cells to directly impact renal function, or whether renal damage is primarily an indirect outcome. To date, several studies have utilized kidney organoids to understand the pathogenesis of COVID-19, revealing the ability for SARS-CoV-2 to predominantly infect cells of the proximal tubule (PT), with reduced infectivity following administration of soluble ACE2. However, the immaturity of standard human kidney organoids represents a significant hurdle, leaving the preferred SARS-CoV-2 processing pathway, existence of alternate viral receptors, and the effect of common hypertensive medications on the expression of ACE2 in the context of SARS-CoV-2 exposure incompletely understood. Utilizing a novel kidney organoid model with enhanced PT maturity, genetic- and drug-mediated inhibition of viral entry and processing factors confirmed the requirement for ACE2 for SARS-CoV-2 entry but showed that the virus can utilize dual viral spike protein processing pathways downstream of ACE2 receptor binding. These include TMPRSS- and CTSL/CTSB-mediated non-endosomal and endocytic pathways, with TMPRSS10 likely playing a more significant role in the non-endosomal pathway in renal cells than TMPRSS2. Finally, treatment with the antihypertensive ACE inhibitor, lisinopril, showed negligible impact on receptor expression or susceptibility of renal cells to infection. This study represents the first in-depth characterization of viral entry in stem cell-derived human kidney organoids with enhanced PTs, providing deeper insight into the renal implications of the ongoing COVID-19 pandemic. IMPORTANCE: Utilizing a human iPSC-derived kidney organoid model with improved proximal tubule (PT) maturity, we identified the mechanism of SARS-CoV-2 entry in renal cells, confirming ACE2 as the sole receptor and revealing redundancy in downstream cell surface TMPRSS- and endocytic Cathepsin-mediated pathways. In addition, these data address the implications of SARS-CoV-2 exposure in the setting of the commonly prescribed ACE-inhibitor, lisinopril, confirming its negligible impact on infection of kidney cells. Taken together, these results provide valuable insight into the mechanism of viral infection in the human kidney.

Outcome of immunosuppression in children with IgA vasculitis-related nephritis.

BACKGROUND AND HYPOTHESIS: IgA vasculitis with nephritis (IgAVN) is the most common vasculitis in children. Treatment recommendations are, due to a lack of evidence, based on expert opinion resulting in variation. The aim of this study was to describe clinical presentation, treatment and outcome of an extremely large cohort of children with biopsy proven IgAVN to identify prognostic risk factors and signals of treatment efficacy. METHODS: Retrospective data were collected on 1148 children with biopsy proven IgAVN between 2005 and 2019 from 41 international paediatric nephrology centres across 25 countries and analyzed using multivariate analysis. The primary outcome was estimated glomerular filtration rate (eGFR) and persistent proteinuria at last follow up. RESULTS: The median follow up was 3.7 years (IQR 2-6.2). At last follow up, 29% of patients had an eGFR < 90 ml/min/1.73m2, 36% had proteinuria and 3% had chronic kidney disease stage 4-5. Older age, lower eGFR at onset, hypertension and histological features of tubular atrophy and segmental sclerosis were predictors of poor outcome. There was no evidence to support any specific second line immunosuppressive regimen to be superior to others, even when further analysing subgroups of children with reduced kidney function, nephrotic syndrome or hypoalbuminemia at onset. Delayed start of immunosuppressive treatment was associated with a lower eGFR at last follow up. CONCLUSION: In this large retrospective cohort, key features associated with disease outcome are highlighted. Importantly there was no evidence to support that any specific immunosuppressive treatments were superior to others. Further discovery science and well-conducted clinical trials are needed to define accurate treatment and improve outcomes of IgAVN.

Development of an Artificial Intelligence Tool for Intraoperative Guidance During Endovascular Abdominal Aortic Aneurysm Repair.

BACKGROUND: Adverse events during surgery can occur in part due to errors in visual perception and judgment. Deep learning is a branch of artificial intelligence (AI) that has shown promise in providing real-time intraoperative guidance. This study aims to train and test the performance of a deep learning model that can identify inappropriate landing zones during endovascular aneurysm repair (EVAR). METHODS: A deep learning model was trained to identify a "No-Go" landing zone during EVAR, defined by coverage of the lowest renal artery by the stent graft. Fluoroscopic images from elective EVAR procedures performed at a single institution and from open-access sources were selected. Annotations of the "No-Go" zone were performed by trained annotators. A 10-fold cross-validation technique was used to evaluate the performance of the model against human annotations. Primary outcomes were intersection-over-union (IoU) and F1 score and secondary outcomes were pixel-wise accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). RESULTS: The AI model was trained using 369 images procured from 110 different patients/videos, including 18 patients/videos (44 images) from open-access sources. For the primary outcomes, IoU and F1 were 0.43 (standard deviation ± 0.29) and 0.53 (±0.32), respectively. For the secondary outcomes, accuracy, sensitivity, specificity, NPV, and PPV were 0.97 (±0.002), 0.51 (±0.34), 0.99 (±0.001). 0.99 (±0.002), and 0.62 (±0.34), respectively. CONCLUSIONS: AI can effectively identify suboptimal areas of stent deployment during EVAR. Further directions include validating the model on datasets from other institutions and assessing its ability to predict optimal stent graft placement and clinical outcomes.

Usefulness of PREDIC3T Case Type Risk Category in the CRISP Registry.

Procedural risk in Congenital Cardiac Catheterization (PREDIC3T) was recently reported as the contemporary procedure-type risk metric by the Congenital Cardiac Catheterization Project on Outcomes (C3PO) registry. The usefulness of this metric has not been evaluated elsewhere. The CRISP registry of Congenital Cardiovascular Interventional Study Consortium (CCISC) data set was analyzed. The study period was 14 years (2009 to 2022). The primary outcome was significant adverse event (SAE). Cases were assigned to the 6 PREDIC3T risk categories. Univariate and multivariable logistic regression models were used to evaluate the association between PREDIC3T and the primary outcome. The model discriminative performance was evaluated by the c-statistic. In a total of 64,419 enrolled cases, PREDIC3T case types were assigned in 59,822 cases (93%). The frequency for PREDIC3T category was 0 = 7,494 (12.5%), 1 = 16,932 (28.3%), 2 = 17,023 (28.5%), 3 = 9,885 (16.5%), 4 = 4,403 (7.4%), and 5 = 4,085 (6.8%). SAE was observed in 2,474 cases (4.1%). The SAE rates for category were 0 = 1.0%, 1 = 2.3%, 2 = 4.0%, 3 = 6.2%, 4 = 8.2%, and 5 = 9.0%. In a multivariable model, PREDIC3T case type risk category (odds ratios for category: 0 = 0.49, 1 = 1.00, 2 = 1.40, 3 = 2.06, 4 = 2.79, and 5 = 3.15; p <0.001) were significantly associated with SAE (c-statistic of 0.707) after adjusting for age, preprocedural inotropic support and systemic illness, low systemic saturation, high pulmonary vascular resistance, and the use of general anesthesia. The PREDIC3T case type risk category was associated with the risk of SAE in the CRISP registry data set and appeared to be a useful procedural risk classification tool.

Machine learning to predict outcomes following endovascular abdominal aortic aneurysm repair.

BACKGROUND: Endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) carries important perioperative risks; however, there are no widely used outcome prediction tools. The aim of this study was to apply machine learning (ML) to develop automated algorithms that predict 1-year mortality following EVAR. METHODS: The Vascular Quality Initiative database was used to identify patients who underwent elective EVAR for infrarenal AAA between 2003 and 2023. Input features included 47 preoperative demographic/clinical variables. The primary outcome was 1-year all-cause mortality. Data were split into training (70 per cent) and test (30 per cent) sets. Using 10-fold cross-validation, 6 ML models were trained using preoperative features with logistic regression as the baseline comparator. The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). Model robustness was evaluated with calibration plot and Brier score. RESULTS: Some 63 655 patients were included. One-year mortality occurred in 3122 (4.9 per cent) patients. The best performing prediction model for 1-year mortality was XGBoost, achieving an AUROC (95 per cent c.i.) of 0.96 (0.95-0.97). Comparatively, logistic regression had an AUROC (95 per cent c.i.) of 0.69 (0.68-0.71). The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.04. The top 3 predictive features in the algorithm were 1) unfit for open AAA repair, 2) functional status, and 3) preoperative dialysis. CONCLUSIONS: In this data set, machine learning was able to predict 1-year mortality following EVAR using preoperative data and outperformed standard logistic regression models.

3-year follow-up of a prospective, multicenter study of the Amplatzer Piccolo™ Occluder for transcatheter patent ductus arteriosus closure in children ≥ 700 grams.

OBJECTIVE: This study describes 3-year follow-up of 200 infants weighing ≥ 700 grams who underwent transcatheter patent ductus arteriosus (PDA) closure with the Amplatzer Piccolo™ Occluder. STUDY DESIGN: Between June 2017 and February 2019, 200 children were enrolled in this U.S. study (NCT03055858). PDA closure, survival, and device- or procedure-related events were evaluated. A total of 156 of the available 182 patients (86%) completed the study. RESULTS: The implant success rate was 95.5% (191/200). At 3 years, PDA closure was observed in 100% (33/33) of patients. Survival was >95% with 9 reported deaths. No deaths were adjudicated as device- or procedure-related. Notable events included aortic obstruction (2) requiring stent placement and tricuspid regurgitation (5), for which no interventions were required. CONCLUSIONS: This follow-up study demonstrates high rates of PDA closure, low serious complication rates, and survival > 95% at 3 years. The Amplatzer Piccolo™ Occluder is a safe and effective therapy for PDA treatment in premature infants. CLINICALTRIALS: gov identifier: NCT0305585.

Rapid Chemical Screening of Microplastics and Nanoplastics by Thermal Desorption and Pyrolysis Mass Spectrometry with Unsupervised Fuzzy Clustering.

The transport and chemical identification of microplastics and nanoplastics (MNPs) are critical to the concerns over plastic accumulation in the environment. Chemically and physically transient MNP species present unique challenges for isolation and analysis due to many factors such as their size, color, surface properties, morphology, and potential for chemical change. These factors contribute to the eventual environmental and toxicological impact of MNPs. As analytical methods and instrumentation continue to be developed for this application, analytical test materials will play an important role. Here, a direct mass spectrometry screening method was developed to rapidly characterize manufactured and weathered MNPs, complementing lengthy pyrolysis-gas chromatography-mass spectrometry analysis. The chromatography-free measurements took advantage of Kendrick mass defect analysis, in-source collision-induced dissociation, and advancements in machine learning approaches for the data analysis of complex mass spectra. In this study, we applied Gaussian mixture models and fuzzy c-means clustering for the unsupervised analysis of MNP sample spectra, incorporating clustering stability and information criterion measurements to determine latent dimensionality. These models provided insight into the composition of mixed and weathered MNP samples. The multiparametric data acquisition and machine learning approach presented improved confidence in polymer identification and differentiation.

Using machine learning to predict outcomes following open abdominal aortic aneurysm repair.

OBJECTIVE: Prediction of outcomes following open abdominal aortic aneurysm (AAA) repair remains challenging with a lack of widely used tools to guide perioperative management. We developed machine learning (ML) algorithms that predict outcomes following open AAA repair. METHODS: The Vascular Quality Initiative (VQI) database was used to identify patients who underwent elective open AAA repair between 2003 and 2023. Input features included 52 preoperative demographic/clinical variables. All available preoperative variables from VQI were used to maximize predictive performance. The primary outcome was in-hospital major adverse cardiovascular event (MACE; composite of myocardial infarction, stroke, or death). Secondary outcomes were individual components of the primary outcome, other in-hospital complications, and 1-year mortality and any reintervention. We split our data into training (70%) and test (30%) sets. Using 10-fold cross-validation, six ML models were trained using preoperative features (Extreme Gradient Boosting [XGBoost], random forest, Naïve Bayes classifier, support vector machine, artificial neural network, and logistic regression). The primary model evaluation metric was area under the receiver operating characteristic curve (AUROC). Model robustness was evaluated with calibration plot and Brier score. The top 10 predictive features in our final model were determined based on variable importance scores. Performance was assessed on subgroups based on age, sex, race, ethnicity, rurality, median area deprivation index, proximal clamp site, prior aortic surgery, and concomitant procedures. RESULTS: Overall, 12,027 patients were included. The primary outcome of in-hospital MACE occurred in 630 patients (5.2%). Compared with patients without a primary outcome, those who developed in-hospital MACE were older with more comorbidities, demonstrated poorer functional status, had more complex aneurysms, and were more likely to require concomitant procedures. Our best performing prediction model for in-hospital MACE was XGBoost, achieving an AUROC of 0.93 (95% confidence interval, 0.92-0.94). Comparatively, logistic regression had an AUROC of 0.71 (95% confidence interval, 0.70-0.73). For secondary outcomes, XGBoost achieved AUROCs between 0.84 and 0.94. The calibration plot showed good agreement between predicted and observed event probabilities with a Brier score of 0.05. These findings highlight the excellent predictive performance of the XGBoost model. The top three predictive features in our algorithm for in-hospital MACE following open AAA repair were: (1) coronary artery disease; (2) American Society of Anesthesiologists classification; and (3) proximal clamp site. Model performance remained robust on all subgroup analyses. CONCLUSIONS: Open AAA repair outcomes can be accurately predicted using preoperative data with our ML models, which perform better than logistic regression. Our automated algorithms can help guide risk-mitigation strategies for patients being considered for open AAA repair to improve outcomes.

Prediction of bird-beak configuration in thoracic endovascular aortic repair preoperatively using patient-specific finite element simulations.

Objectives: Formation of bird-beak configuration in thoracic endovascular aortic repair (TEVAR) has been shown to be correlated with the risk of complications such as type Ia endoleaks, stent graft migration, and collapse. The aim of this study was to use patient-specific computational simulations of TEVAR to predict the formation of bird-beak configuration preoperatively. Methods: Patient-specific TEVAR computational simulations are developed using a retrospective cohort of patients treated for thoracic aortic aneurysm. The preoperative computed tomography images were segmented to develop three-dimensional geometry of the thoracic aorta. These geometries were used in finite element simulations of stent graft deployment during TEVAR. Simulated results were compared against the postoperative computed tomography images to assess the accuracy of simulations in predicting the proximal position of a deployed stent graft and presence of bird-beak. In cases with a bird-beak configuration, the length and angle of the bird-beak were measured and compared between the simulated and postoperative results. Results: Twelve TEVAR patient cases were simulated. Computational simulations were able to accurately predict whether the proximal stent graft was fully apposed, proximal bare stents were protruded, or bird-beak configuration was present. In three cases with bird-beak configuration, simulations predicted the length and angle of the bird-beak with less than 10% and 24% error, respectively. Other factors such as a small aortic arch angle, small oversizing value, and landing zones close to the arch apex may have played a role in formation of bird-beak in these patients. Conclusions: Computational simulations of TEVAR accurately predicted the proximal position of a deployed stent graft and the presence of bird-beak preoperatively. The computational models were able to predict the length and angle of bird-beak configurations with good accuracy. These simulations can provide insight into the surgical planning process with the goal of minimizing bird-beak occurrence.

Ascending aortic geometry and its relationship to the biomechanical properties of aortic tissue.

Objective: The objective of this study was to evaluate the relationship between ascending aortic geometry and biomechanical properties. Methods: Preoperative computed tomography scans from ascending aortic aneurysm patients were analyzed using a center line technique (n = 68). Aortic length was measured from annulus to innominate artery, and maximal diameter from this segment was recorded. Biaxial tensile testing of excised tissue was performed to derive biomechanical parameters energy loss (efficiency in performing the Windkessel function) and modulus of elasticity (stiffness). Delamination testing (simulation of dissection) was performed to derive delamination strength (strength between tissue layers). Results: Aortic diameter weakly correlated with energy loss (r 2 = 0.10; P < .01), but not with modulus of elasticity (P = .13) or delamination strength (P = .36). Aortic length was not associated with energy loss (P = .87), modulus of elasticity (P = .13) or delamination strength (P = .90). Using current diameter guidelines, aortas >55 mm (n = 33) demonstrated higher energy loss than those <55 mm (n = 35; P = .05), but no difference in modulus of elasticity (P = .25) or delamination strength (P = .89). A length cutoff of 110 mm was proposed as an indication for repair. Aortas >110 mm (n = 37) did not exhibit a difference in energy loss (P = .40), modulus of elasticity (P = .69), or delamination strength (P = .68) compared with aortas <110 mm (n = 31). Aortas above diameter and length thresholds (n = 21) showed no difference in energy loss (P = .35), modulus of elasticity (P = .55), or delamination strength (P = .61) compared with smaller aortas (n = 47). Conclusions: Aortic geometry poorly reflects the mechanical properties of aortic tissue. Weak association between energy loss and diameter supports intervention at larger diameters. Further research into markers that better capture aortic biomechanics is needed.

General versus loco-regional anesthesia for endovascular aortic aneurysm repair.

BACKGROUND: Aortic aneurysms occur when the aorta, the body's largest artery, grows in size, and can occur in the thoracic or abdominal aorta. The approaches to repair aortic aneurysms include directly exposing the aorta and replacing the diseased segment via open repair, or endovascular repair. Endovascular repair uses fluoroscopic-guidance to access the aorta and deliver a device to exclude the aneurysmal aortic segment without requiring a large surgical incision. Endovascular repair can be performed under a general anesthetic, during which the unconscious patient is paralyzed and reliant on an anesthetic machine to maintain the airway and provide oxygen to the lungs, or a loco-regional anesethetic, for which medications are administered to provide the person with sufficient sedation and pain control without requiring a general anesthetic. While people undergoing general anesthesia are more likely to remain still during surgery and have a well-controlled airway in the event of unanticipated complications, loco-regional anesthesia is associated with fewer postoperative complications in some studies. It remains unclear which anesthetic technique is associated with better outcomes following the endovascular repair of aortic aneurysms. OBJECTIVES: To evaluate the benefits and harms of general anesthesia compared to loco-regional anesthesia for endovascular aortic aneurysm repair. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search was 11 March 2022. SELECTION CRITERIA: We searched for all randomized controlled trials that assessed the effects of general anesthesia compared to loco-regional anesthesia for endovascular aortic aneurysm repairs. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were: all-cause mortality, length of hospital stay, length of intensive care unit stay. Our secondary outcomes were: incidence of endoleaks, requirement for re-intervention, incidence of myocardial infarction, quality of life, incidence of respiratory complications, incidence of pulmonary embolism, incidence of deep vein thrombosis, and length of procedure. We planned to use GRADE methodology to assess the certainty of evidence for each outcome. MAIN RESULTS: We found no studies, published or ongoing, that met our inclusion criteria. AUTHORS' CONCLUSIONS: We did not identify any randomized controlled trials that compared general versus loco-regional anesthesia for endovascular aortic aneurysm repair. There is currently insufficient high-quality evidence to determine the benefits or harms of either anesthetic approach during endovascular aortic aneurysm repair. Well-designed prospective randomized trials with relevant clinical outcomes are needed to adequately address this.

A Comparison of Vessel Patch Materials in Tetralogy of Fallot Patients Using Virtual Surgery Techniques.

Tetralogy of Fallot (ToF) is characterized by stenosis causing partial obstruction of the right ventricular outflow tract, typically alleviated through the surgical application of a vessel patch made from a biocompatible material. In this study, we use computational simulations to compare the mechanical performance of four patch materials for various stenosis locations. Nine idealized pre-operative ToF geometries were created by imposing symmetrical stenoses on each of three anatomical sub-regions of the pulmonary arteries of three patients with previously repaired ToF. A virtual surgery methodology was implemented to replicate the steps of vessel de-pressurization, surgical patching, and subsequent vessel expansion after reperfusion. Significant differences in patch average stress (p < 0.001) were found between patch materials. Biological patch materials (porcine xenopericardium, human pericardium) exhibited higher patch stresses in comparison to synthetic patch materials (Dacron and PTFE). Observed differences were consistent across the various stenosis locations and were insensitive to patient anatomy.