An in vitro Assessment of the Haemodynamic Features Occurring Within the True and False Lumens Separated by a Dissection Flap for a Patient-Specific Type B Aortic Dissection.

One of the highest mortality rates of cardiovascular diseases is aortic dissections with challenging treatment options. Currently, less study has been conducted in developing in vitro patient-specific Type B aortic dissection models, which mimic physiological flow conditions along the true and false lumens separated by a dissection flap with multiple entry and exit tears. A patient-specific Stanford Type B aortic dissection scan was replicated by an in-house manufactured automatic injection moulding system and a novel modelling technique for creating the ascending aorta, aortic arch, and descending aorta incorporating arterial branching, the true/false lumens, and dissection flap with entry and exit intimal tears. The physiological flowrates and pressure values were monitored, which identified jet stream fluid flows entering and exiting the dissection tears. Pressure in the aorta's true lumen region was controlled at 125/85 mmHg for systolic and diastolic values. Pressure values were obtained in eight sections along the false lumen using a pressure transducer. The true lumen systolic pressure varied from 122 to 128 mmHg along the length. Flow patterns were monitored by ultrasound along 12 sections. Detailed images obtained from the ultrasound transducer probe showed varied flow patterns with one or multiple jet steam vortices along the aorta model. The dissection flap movement was assessed at four sections of the patient-specific aorta model. The displacement values of the flap varied from 0.5 to 3 mm along the model. This model provides a unique insight into aortic dissection flow patterns and pressure distributions. This dissection phantom model can be used to assess various treatment options based on the surgical, endovascular, or hybrid techniques.

Systematic Review on Endovascular Access to Intracranial Arteries for Mechanical Thrombectomy in Acute Ischemic Stroke.

PURPOSE: In acute ischemic stroke for large vessel occlusions, delayed or failed access to intracranial occlusions has a negative impact on procedural and clinical outcomes. The aim of this review is to identify and quantify access failures and challenges in mechanical thrombectomy. METHODS: A systematic literature review of PubMed and Scopus databases from January 2014 to October 2020 was performed. Articles reporting consecutive patients were used to calculate a crude failure rate of femoral and alternative accesses. RESULTS: A total of 50 articles met the inclusion criteria, totalling 12,838 interventions. Failure to access the occlusion through transfemoral access occurred in 4.4% of patients, most commonly due to challenging supra-aortic vessel anatomy, decreasing to 3.6% when all alternative access routes were attempted. Failed access from alternative routes (direct carotid, radial and brachial approaches) attempted first-line or after failed femoral attempt were reported in 7.3% of patients. The occurrence rate of potentially challenging features (anatomical, diseases or others) ranged from 4.7% to 47.4%, primarily impacting the access time, procedure time, recanalization and clinical outcomes. CONCLUSION: Failure to access the occlusion is a significant contributor to failed recanalization, regardless of access routes. Challenging, but eventually successful access is also a relevant factor in procedural and clinical outcomes; however challenging access requires a universal definition to enable quantification, so that methods for procedural optimization can be critically assessed.

Hybrid repair versus conventional open repair for thoracic aortic arch aneurysms.

BACKGROUND: Thoracic aortic arch aneurysms (TAAs) can be a life-threatening condition due to the potential risk of rupture. Treatment is recommended when the risk of rupture is greater than the risk of surgical complications. Depending on the cause, size and growth rate of the TAA, treatment may vary from close observation to emergency surgery. Aneurysms of the thoracic aorta can be managed by a number of surgical techniques. Open surgical repair (OSR) of aneurysms involves either partial or total replacement of the aorta, which is dependent on the extent of the diseased segment of the aorta. During OSR, the aneurysm is replaced with a synthetic graft. Hybrid repair (HR) involves a combination of open surgery with endovascular aortic stent graft placement. Hybrid repair requires varying degrees of invasiveness, depending on the number of supra-aortic branches that require debranching. The hybrid technique that combines supra-aortic vascular debranching with stent grafting of the aortic arch has been introduced as a therapeutic alternative. However, the short- and long-term outcomes of HR remain unclear, due to technical difficulties and complications as a result of the angulation of the aortic arch as well as handling of the arch during surgery. OBJECTIVES: To assess the effectiveness and safety of HR versus conventional OSR for the treatment of TAAs. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 22 March 2021. We also searched references of relevant articles retrieved from the electronic search for additional citations. SELECTION CRITERIA: We considered for inclusion in the review all published and unpublished randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing HR to OSR for TAAs. DATA COLLECTION AND ANALYSIS: Two review authors independently screened all titles and abstracts obtained from the literature search to identify those that met the inclusion criteria. We retrieved the full text of studies deemed as potentially relevant by at least one review author. The same review authors screened the full-text articles independently for inclusion or exclusion. MAIN RESULTS: No RCTs or CCTs met the inclusion criteria for this review. AUTHORS' CONCLUSIONS: Due to the lack of RCTs or CCTs, we were unable to determine the safety and effectiveness of HR compared to OSR in people with TAAs, and we are unable to provide high-certainty evidence on the optimal surgical intervention for this cohort of patients. High-quality RCTs or CCTs are necessary, addressing the objective of this review.

Class imbalance in gradient boosting classification algorithms: Application to experimental stroke data.

Imbalance between positive and negative outcomes, a so-called class imbalance, is a problem generally found in medical data. Imbalanced data hinder the performance of conventional classification methods which aim to improve the overall accuracy of the model without accounting for uneven distribution of the classes. To rectify this, the data can be resampled by oversampling the positive (minority) class until the classes are approximately equally represented. After that, a prediction model such as gradient boosting algorithm can be fitted with greater confidence. This classification method allows for non-linear relationships and deep interactive effects while focusing on difficult areas by iterative shifting towards problematic observations. In this study, we demonstrate application of these methods to medical data and develop a practical framework for evaluation of features contributing into the probability of stroke.

An in-vitro evaluation of the flow haemodynamic performance of Gore-Tex extracardiac conduits for univentricular circulation.

OBJECTIVE(S): The Fontan procedure is a common palliative intervention for sufferers of single ventricle congenital heart defects that results in an anastomosis of the venous return to the pulmonary arteries called the total cavopulmonary connection (TCPC). In patients with palliated single ventricular heart defects, the Fontan circulation passively directs systemic venous return to the pulmonary circulation in the absence of a functional sub-pulmonary ventricle. Therefore, the Fontan circulation is highly dependent on favourable flow and energetics, and minimal energy loss is of great importance. The majority of in vitro studies, to date, employ a rigid TCPC model. Recently, few studies have incorporated flexible TCPC models, without the inclusion of commercially available conduits used in these surgical scenarios. METHOD: The methodology set out in this study successfully utilizes patient-specific phantoms along with the corresponding flowrate waveforms to characterise the flow haemodynamic performance of extracardiac Gore-Tex conduits. This was achieved by comparing a rigid and flexible TCPC models against a flexible model with an integrated Gore-Tex conduit. RESULTS: The flexible model with the integrated Gore-Tex graft exhibited greater levels of energy losses when compared to the rigid walled model. With this, the flow fields showed greater levels of turbulence in the complaint and Gore-Tex models compared to the rigid model under ultrasound analysis. CONCLUSION: This study shows that vessel compliance along with the incorporation of Gore-Tex extracardiac conduits have significant impact on the flow haemodynamics in a patient-specific surgical scenario.

An in vitro assessment of atrial fibrillation flow types on cardiogenic emboli trajectory paths.

Atrial fibrillation is the most significant contributor to thrombus formation within the heart and is responsible for 45% of all cardio embolic strokes, which account for approximately 15% of acute ischemic strokes cases worldwide. Atrial fibrillation can result in a reduction of normal cardiac output and cycle length of up to 30% and 40%, respectively. A total of 240 embolus analogues were released into a thin-walled, patient-specific aortic arch under normal (60 embolus analogues) and varying atrial fibrillation (180 embolus analogues) pulsatile flow conditions. Under healthy flow conditions (n = 60), the embolus analogues tended to follow the flow rate split through each outlet vessel. There was an increase in clot trajectories along the common carotid arteries under atrial fibrillation flow conditions. A shorter pulse period (0.3 s) displayed the highest percentage of clots travelling to the brain (24%), with a greater percentage of clots travelling through the left common carotid artery (17%). This study provides an experimental insight into the effect varying cardiac output and cycle length can have on the trajectory of a cardiac source blood clots travelling to the cerebral vasculature and possibly causing a stroke.

Shape of Training Review: an impact assessment for UK gastroenterology trainees.

BACKGROUND: Physician training in the UK is undergoing considerable change due to the implementation of recommendations made in the Shape of Training Review. In particular, higher specialty training (HST), including gastroenterology, will be shortened from 5 to 4 years. This will also incorporate general internal medicine (GIM) training. There is concern among gastroenterologists regarding how high-quality gastroenterology training will be delivered in 4 years. METHODS: The 2018 British Society of Gastroenterology (BSG) trainees' survey results were used to examine the potential impact of a 4-year HST period on achieving key competencies in gastroenterology. RESULTS: 291 (49.4%) gastroenterology trainees responded. Satisfaction with gastroenterology training was high (79.6% respondents), and self-reported confidence in hepatology training was also high (84% senior respondents). However, only half (51.1%) of the respondents achieved complete colonoscopy certification by their final year of training. Comparison with the 2014 BSG trainees' survey demonstrated that the number of endoscopy procedures achieved by trainees has reduced in sigmoidoscopy (p=0.006) and colonoscopy (p<0.001). The proportion of time spent in GIM training has increased since the last survey, with 81.8% of the respondents spending more than 25% of their time in GIM. GIM training was reported to be a key barrier to adequate gastroenterology and endoscopy training. CONCLUSION: These data indicate significant barriers to delivering gastroenterology and endoscopy training within the current 5-year programme. Novel strategies will be required to improve the rate of progression in endoscopy training, in particular if high-quality gastroenterology HST training is to be delivered in 4 years.

Changes in left ventricular shape and morphology in the presence of heart failure: a four-dimensional quantitative and qualitative analysis.

PURPOSE: The presence and progression of heart failure (HF) are associated with cardiac remodelling, defined as cellular, molecular and interstitial changes which occur after injury and manifest as changes in left ventricular (LV) size, mass, geometry and function. This research study was designed to investigate the changes to LV morphology and shape which occur in the presence of heart failure using three-dimensional (3D) modelling and analysis of cardiac-gated CT scans from both healthy individuals and patients classified with HF. METHODS: A number of quantitative and qualitative strategies were applied to cardiac CT scans of HF patients and healthy controls (n = 7) in order to analyse changes to LV size, shape and structure and to examine LV remodelling in the different classes of HF. Three-dimensional wireframe representations of endocardial and epicardial borders were created, three-dimensional computer stereolithography models of the inner LV cavity and myocardial wall segments were generated and three-dimensionally printed and a number of clinical LV dimension and shape indices were measured. All data were analysed using one-way ANOVA with post hoc Tukey method for multiple comparisons for significant variables. RESULTS: Results of most significance included abnormalities in LV mass and end-systolic dimensions and significantly increased septal wall thickness among mid-range ejection fraction cases. Also of importance were significant increases in both dimension-based and volumetric sphericity index measures in all HF cases. Three-dimensional printed models provided qualitative information as to changes in inner LV cavity and myocardial wall morphology across the cardiac cycle for healthy and HF cases and validated quantitative findings. CONCLUSION: Findings from this study can successfully be applied to motivate the research and development of new HF treatment strategies and devices as well as for the development of a realistic cardiac simulator system.

Investigation of the Hemodynamics Influencing Emboli Trajectories Through a Patient-Specific Aortic Arch Model.

Background and Purpose- Cardiogenic emboli account for 15% to 20% of acute ischemic stroke cases worldwide. However, the chance of such emboli, of varying sizes, causing a stroke under various flow types has not been evaluated. Methods- A patient-specific aortic arch model was fabricated from a medical image dataset of a 77-year-old male case, with atrial fibrillation and distal occlusion of the right M1 vessel. One hundred and eighty mammalian embolus analogs (EAs) were released one by one into the model under normal and atrial fibrillation flow conditions. A further 270 clots were fabricated using varying levels of thrombin (5-20 National Institutes of Health units thrombin). The effect of releasing several clots simultaneously was also examined by grouping EAs into 18 multiples of 5, 4, 3, and 2 clots, resulting in 504 EAs released. Results- EAs with a length of ≤10 mm were the most common geometry to travel through the common carotid arteries (44%); however, longer clots also traveled through these narrow vessels. Twenty two percent of EAs ranged from 10-20mm in length, 27% from 20-30mm and 7% were >30 mm in length. Higher density clots increased the propensity for clots to travel along the cerebral vessels ( P<0.05). Releasing more clots during each test, increased the probability of at least one clot traveling through an aortic arch branching vessel. Conclusions- Embolus trajectory through the branching vessels of the aortic arch is not exclusively dependent on embolus size. EAs tend to travel proportionally with outlet flow rates, with a greater chance of a stroke caused by multiple breakaway emboli.

Per-Pass Analysis of Thrombus Composition in Patients With Acute Ischemic Stroke Undergoing Mechanical Thrombectomy.

Background and Purpose- Mechanical thrombectomy may involve multiple attempts to retrieve the occluding thrombus. This study examined the composition of thrombus fragments retrieved with each pass of a device during the thrombectomy procedure. Second, the per-pass composition was compared with procedural and clinical data including angiographic outcome and stroke etiology. Methods- Thrombi were retrieved from 60 patients with acute ischemic stroke, where thrombus fragments retrieved in each pass were segregated as individual samples and maintained throughout the histological analysis as independent samples. All samples were stained with hematoxylin and eosin and Martius Scarlet Blue. The relative composition of red blood cells, fibrin, and white blood cells in thrombus fragments from each pass was quantified. Results- Over the 60 cases, thrombus material was retrieved in 106 of 138 passes. The number of passes required to complete the cases ranged from 1 to 6 passes. The analysis of thrombus fragments retrieved in each pass provided a greater insight into the thrombectomy procedure progression than the overall thrombus composition; the red blood cell content of thrombus fragments retrieved in passes 1 and 2 was significantly higher than that retrieved in passes 3 to 6. The removal of thrombus material in a total of 1, 2, or 3 passes was associated with the highest percentage of final modified Thrombolysis in Cerebral Infarction score of 2c-3. There was no association between modified Thrombolysis in Cerebral Infarction score and per-pass thrombus composition. Conclusions- The differentiation achieved through the per-pass analysis of acute ischemic stroke thrombi provides a greater insight into the thrombectomy procedure progression than the combined per-case thrombus analysis. Insights gained may be a useful consideration in determining the treatment strategy as a case evolves and may be useful for the development of new devices to increase rates of 1-pass recanalization.

Establishment of an Automated Algorithm Utilizing Optical Coherence Tomography and Micro-Computed Tomography Imaging to Reconstruct the 3-D Deformed Stent Geometry.

Percutaneous coronary intervention (PCI) is the prevalent treatment for coronary artery disease, with hundreds of thousands of stents implanted annually. Computational studies have demonstrated the role of biomechanics in the failure of vascular stents, but clinical studies is this area are limited by a lack of understanding of the deployed stent geometry, which is required to accurately model and predict the stent-induced in vivo biomechanical environment. Herein, we present an automated method to reconstruct the 3-D deployed stent configuration through the fusion of optical coherence tomography (OCT) and micro-computed tomography ( µ CT) imaging data. In an experimental setup, OCT and µ CT data were collected in stents deployed in arterial phantoms ( n=4 ). A constrained iterative deformation process directed by diffeomorphic metric mapping was developed to deform µ CT data of a stent wireframe to the OCT-derived sparse point cloud of the deployed stent. Reconstructions of the deployed stents showed excellent agreement with the ground-truth configurations, with the distance between corresponding points on the reconstructed and ground-truth configurations of [Formula: see text]. Finally, reconstructions required <30 min of computational time. In conclusion, the developed and validated reconstruction algorithm provides a complete spatially resolved reconstruction of a deployed vascular stent from commercially available imaging modalities and has the potential, with further development, to provide more accurate computational models to evaluate the in vivo post-stent mechanical environment, as well as clinical visualization of the 3-D stent geometry immediately following PCI.

The Weight-Focused Forms of Self-Criticising/Attacking and Self-Reassuring Scale: Confirmatory Factor Analysis and associations with control, loss of control of eating and weight in overweight and obese women.

OBJECTIVES: The Weight-Focused Forms of Self-Criticising/Attacking and Self-Reassuring Scale (WFSCRS) is based on the original Forms of Self-Criticising/Attacking and Self-Reassuring Scale (FSCSRS; Gilbert et al., 2004, British Journal of Clinical Psychology, 43, 31) and assesses the inadequate and hated forms of self-criticism and the ability to self-reassure when coping with attempts to control body weight, shape, and eating. The aim of this study was to examine the factor structure, consistency, and reliability of the WFSCRS in overweight and obese women. METHODS: The factorial structure of the WFSCRS was examined through a confirmatory factor analysis in 724 overweight and obese women participating in a commercial weight management programme. The scale's construct and convergent validity were also examined. RESULTS: The WFSCRS had a three-factor structure, similar to the FSCSRS, which fitted the data well. The WFSCRS had high internal reliability, construct, and discriminant validity. The scale was positively associated with measures of shame, body image, eating-related difficulties, symptoms of anxiety, depression, and stress, and body mass index (BMI). The two forms of self-criticism were significantly associated with higher BMI, and this effect was mediated by increased loss of control over eating (for both forms) and decreased flexible control over eating (for the hated self form). CONCLUSIONS: The WFSCRS is a valid measure for assessing self-reassurance and two denigratory forms (inadequate self and hated self) of self-criticism in people who are overweight and obese. PRACTITIONER POINTS: The WFSCRS was developed to measure weight/shape and eating-related self-criticism and self-reassurance. The WFSCRS was examined in a large sample of overweight and obese women attending a community-based weight management programme. The WFSCRS presented a three-factor structure measuring two forms of self-criticism (inadequate self and hated self) and the ability to be self-reassuring. The two forms of self-criticism and self-reassurance are differentially associated with BMI, through the mediating effect of loss of control over eating and flexible control over eating.

Reduction of vascular complication rates from femoral artery access in contemporary women undergoing cardiac catheterization.

BACKGROUND: Femoral arterial access (FAA) during diagnostic coronary angiography (CAG) and percutaneous coronary interventions (PCI) are associated with several vascular complications (VC). VC rate in our experience a decade ago was 3.02% and higher in women (4.7% in women, and 1.67% in men, p < 0.0006), with an OR of 2.81 (95% CI: 1.51-5.22). METHODS: Patients who underwent CAG and PCI utilizing FAA (n = 2617) were separated into Period 1 (2005 to 2008; 1970 patients; Male 1045; Female 925) and Period 2 (2016-2017; 647 patients; Male 357; Female 290). FA access was preceded by anatomic FA localization during Period 1 vs. additional fluoroscopic marking of femoral head during Period 2. Ultrasound guidance was not utilized during either period. VCs were defined as hematoma>3 cm, major bleeding requiring blood transfusion or hemoglobin drop >2 g, retroperitoneal bleed, pseudoaneurysm, AV fistula, arterial thrombosis, distal embolism, dissection, and transient limb ischemia. RESULTS: Rate of VCs did not differ from Periods 1 to 2 (2.44% vs. 2.32%, p = 1.0). An elevated rate of VCs experienced by women in Period 1 (Female 3.68% vs. Male 1.34%, p < 0.05) is no longer noted in Period 2(Female 2.07% vs. Male 2.52%, p = 0.79). Vascular closure device (VCD) use was protective in both Periods 1 and 2. CONCLUSIONS: The use of fluoroscopic marking of femoral head prior to access, smaller sheath size, and being a high femoral volume center may have contributed to the reduced incidence of VCs in women. VCD utilization is continuing to reduce VC rates in both men and women.

Does micropuncture technique really help reduce vascular complications?

BACKGROUND: Micropuncture technique (MPT) is being adapted nationally to reduce vascular complications (VC). We initiated a quality improvement project in our cath lab to reduce VCs utilizing MPT. METHODS: We utilized MPT on all of our non-STEMI femoral artery (FA) access cases starting September 2016. As a comparator group, we collected data from April to August 2016. Anatomic localization of FA and fluoroscopic marking of femoral head was utilized in all cases. VCs were defined by BARC definitions for bleeding/hematomas, retroperitoneal bleed, pseudoaneurysm, AV fistula, arterial thrombosis, distal embolism, dissection, and transient limb ischemia. RESULTS: A total of 647 patients (Male 357, Female 290; MPT 333) were included in the analysis. MPT as compared to regular 18-gauge needle access did not demonstrate a reduction in VCs (2.4% vs. 2.2%; p = 1.0). MPT utilization did not affect the risk of VCs on univariate (OR 1.08; 95% CI 0.38-3.01; p = 0.88) or multivariate analysis (OR 0.91, 95% CI 0.28-2.93; p + 0.87). Vascular closure device (VCD) utilization as compared to manual/fem-stop hemostasis was the only factor that demonstrated a statistically significant and lower VC rate on both univariate (OR 0.28; 95% CI: 0.08-0.89; p = 0.03), and multivariate (OR 0.24; 95% CI 0.06-0.93; p = 0.039) analysis. CONCLUSION: Utilization of MPT in conjunction with fluoroscopic marking of the femoral head and without ultrasound guidance did not contribute to statistically significant reduction in the VC rate. The only factor found to be beneficial is utilization of VCDs. Further large randomized studies are required to demonstrate benefit of routinely utilizing MPT.

The Impact of Self-Criticism and Self-Reassurance on Weight-Related Affect and Well-Being in Participants of a Commercial Weight Management Programme.

OBJECTIVE: Certain psychological and emotional factors can undermine attempts at weight management. Previously we have found that shame and self-criticism were significantly associated with disinhibition and perceived hunger in 2,236 participants of a weight management programme. This effect was fully mediated through weight-related negative affect. The present study examined the impact of self-criticism and self-reassurance on well-being and whether it was mediated by weight-related affect in the same population. METHODS: Participants completed an online survey of measures of self-criticism and self-reassurance, and negative and positive affect associated with weight and well-being. RESULTS: Path analysis suggested that self-criticism was significantly associated with decreased well-being, both directly and indirectly, mediated by increased negative and decreased positive weight-related affect. Self-reassurance had a stronger association with increased well-being by predicting lower negative and increased positive weight-related affect. All effects were significant at p < 0.001. CONCLUSION: Self-criticism and self-reassurance were related to well-being in participants attempting to manage their weight, both directly and through their impact on weight-related affect. The positive association between self-reassurance and well-being was stronger than the negative association between self-criticism and well-being. Supporting the development of self-reassuring competencies in weight management programmes may improve weight-related affect and well-being.

The Impact of Shame, Self-Criticism and Social Rank on Eating Behaviours in Overweight and Obese Women Participating in a Weight Management Programme.

Recent research has suggested that obesity is a stigmatised condition. Concerns with personal inferiority (social rank), shame and self-criticism may impact on weight management behaviours. The current study examined associations between social comparison (shame, self-criticism), negative affect and eating behaviours in women attending a community based weight management programme focused on behaviour change. 2,236 participants of the programme completed an online survey using measures of shame, self-criticism, social comparison, and weight-related affect, which were adapted to specifically address eating behaviour, weight and body shape perceptions. Correlation analyses showed that shame, self-criticism and social comparison were associated with negative affect. All of these variables were related to eating regulation and weight control (p < 0.001). Path analysis revealed that the association of shame, hated-self, and low self-reassurance on disinhibition and susceptibility to hunger was fully mediated by weight-related negative affect, even when controlling for the effect of depressive symptoms (p < 0.050 to p < 0.010). In addition, feelings of inadequacy and unfavourable social comparisons were associated with higher disinhibition and susceptibility to hunger, partially mediated through weight-related negative affect (p = 0.001). These variables were negatively associated with extent of weight loss during programme attendance prior to the survey, while self-reassurance and positive social comparisons were positively associated with the extent of weight loss prior to the survey (p < .050). Shame, self-criticism, and perceptions of inferiority may play a significant role in self-regulation of eating behaviour in overweight people trying to manage their weight.

Computational fluid analysis of symptomatic chronic type B aortic dissections managed with the Streamliner Multilayer Flow Modulator.

OBJECTIVE: Managing symptomatic chronic type B aortic dissection (SCTBAD) by the Streamliner Multilayer Flow Modulator (SMFM) stent (Cardiatis, Isnes, Belgium) is akin to provisional structural support to induce complete attachment of the dissection flap, but with the ability of aortic remolding. This study investigated the SMFM's capability to enact healing of SCTBAD. METHODS: Clinical data for 12 cases comprising preoperative and postoperative treatment of SCTBAD were obtained from a multicenter database hosted by the Multilayer Flow Modulator Global Registry, Ireland. A biomechanical analysis, by means of computational fluid dynamics modeling, of the hemodynamic effects and branch patency associated with the use of the SMFM was performed for all cases. The mean length of the dissections was 30.23 ± 13.3 cm. There were 30 SMFMs used, which covered 69 aortic branches. RESULTS: At 1-year follow-up, the true lumen volume increased from 175.74 ± 98.83 cm3 to 209.87 ± 128.79 cm3; the false lumen decreased from 135.2 ± 92.03 cm3 to 123.19 ± 110.11 cm3. The false lumen index decreased from 0.29 ± 0.13 (preoperatively) to 0.21 ± 0.15 (postoperatively). The primary SMFM treatment of SCTBAD increased carotid perfusion by 35% ± 21% (P = .0216) and suprarenal perfusion by 78% ± 32% (P = .001). The wall pressure distribution blended along the newly enlarged true lumen, whereas the false lumen wall pressure decreased by 6.23% ± 4.81% for the primary group (cases 1-7) and by 3.84% ± 2.59% for the secondary group (cases 8-12). CONCLUSIONS: SMFM reduces the false lumen wall pressure through flow modulation. It preserves patency of all branches, minimizing the incidence of short-term complications. The SMFM is a valuable option in managing primary SCTBAD, without midterm complications.

Novel methodology to replicate clot analogs with diverse composition in acute ischemic stroke.

BACKGROUND: Translational research on clot composition may be advanced by the use of clot analogs for the preclinical evaluation of mechanical thrombectomy devices. This work describes a novel set of clot analogs to represent a diverse range of fibrin and red blood cell (RBC) compositions for use in acute ischemic stroke (AIS) occlusion models. METHOD: Fresh whole blood obtained from ovine species was used to create seven different clot analog types. Five replicates were formed for each clot type. Varying amounts of whole blood constituents were mixed with thrombotic factors to create clots of varying compositions. Following histological processing, five sections from each clot were stained with H&E and Martius Scarlet Blue. Fibrin, RBC and white blood cell compositions were quantified. RESULTS: Histological examination demonstrated that the clot types had a distinct RBC and fibrin composition. No significant difference in composition was shown between replicates (p>0.05), indicating that the method of clot formation was reproducible. Percentage fibrin composition of the clot types was 1%, 8%, 31%, 38%, 64%, 79%, and 100%. A significant difference in fibrin and RBC composition between clot types was observed (p<0.05). CONCLUSIONS: Seven different clot types were developed to replicate common AIS thrombi. These clot analogs may be beneficial for the preclinical evaluation of endovascular therapies, and may be applied to interventional technique training.