Changes In Lumen Diameter Research Articles

Mid-term Outcomes of Thoracic Endovascular Aortic Repair (TEVAR) in Acute Complicated Type B Aortic Dissection: A Comprehensive Analysis of Aortic Remodeling Patterns.

This study provides a comprehensive analysis of the clinical outcomes associated with endovascular treatment for acute complicated type B aortic dissection, with a focus on the complex process of aortic remodeling. We conducted a retrospective investigation using data extracted from the Songklanagarind Hospital database between January 2010 and January 2022. Electronic medical records of patients who underwent thoracic endovascular aortic repair (TEVAR) for acute complicated type B aortic dissections were reviewed. The analysis focused on in-hospital outcomes, overall survival, aorta-related survival, reintervention-free survival, and changes in aortic lumen diameter to assess aortic remodeling. Over the study period, 32 patients with acute complicated type B aortic dissections underwent TEVAR. The in-hospital mortality rate was 9.4%, with complications occurring in 21.9% of patients. Temporary acute kidney injury was observed in 9.4% of the cases, wound bleeding in 6.3%, pneumonia in 6.3%, and permanent spinal cord ischemia in 3.1%. Re-intervention was necessary in 6.3% of cases. The overall survival rates at 6 months, 1 year, 3 years, and 6 years were 78%, 75%, 65%, and 44%, respectively. Aorta-related survival rates were 87%, 87%, 83%, and 75% at the corresponding time intervals. The reintervention-free survival rates were 96%, 96%, 71%, and 71%, respectively. Survival analysis revealed that patients with ideal aortic remodeling experienced the most favorable outcomes, whereas those with undesirable aortic remodeling exhibited the least favorable survival. Notably, undesirable pattern of aortic remodeling emerged as a singular factor with a statistically significant influence on predicting survival (hazard ratio 4.37, P-value=0.021). TEVAR resulted in favorable aorta-related survival outcomes. Notably, the identification of changes in aortic lumen diameter alongside false lumen thrombosis, encapsulated within the framework of aortic remodeling patterns, has emerged as a robust predictor of post-TEVAR survival outcomes.

Bare Stent Fracture After TEVAR With the Modified Restrictive Bare Stent (RBS) Technique in Type B Aortic Dissections.

The aim was to assess the mid-term aortic remodeling and bare-metal stent (BMS) integrity of the restricted bare stent (RBS) technique reconstruction in aortic dissections. This retrospective cohort study included prospectively collected patients treated with the modified RBS technique between 2017 and 2020. The preoperative, postoperative, and last follow-up computed tomographic (CT) scans were analyzed in the centerline at the mid-descending, celiac trunk (CeT), and the mid-abdominal levels for false lumen (FL) patency, aortic diameter, and true lumen (TL) diameter changes. Bare-metal stent integrity was assessed in the 3-dimensional multiplanar reformats. The median follow-up of the cohort (n=17) was 26 (11, 45) months. The procedure was mainly performed with the Relay NBS endograft (15/17; 88%) + E-XL BMS (17/17; 100%). Postoperative mortality, paraplegia, stroke, renovisceral vessel loss, and type I and III endoleaks were not observed. BMS fractured in 6 patients (6/17; 36%), damaged the dissection flap in 4/17 (24%), and led to the reperfusion of the FL and re-interventions with TEVAR (4/17; 24%). Two patients without FL reperfusion showed stable CT follow-ups 13 and 17 months after the fracture diagnosis. The TL expansion was seen at all landmarks and peaked in the thoracic aorta (+10; 6, 15; p<0.001). The FL thrombosis after modified RBS was only relevant in the thoracic aorta (p<0.001) and at CeT (p=0.003). The aortic diameter was stable in the thoracic aorta and increased at distal landmarks (CeT [+5; 1, 10; p=0.001]; mid-abdominal [+3; 1, 5; p=0.004]). The modified RBS technique could not stop aortic growth below the diaphragm and prevent new membrane rupture due to the fractures of the BMS and consecutive flap damage with the reperfusion of the FL. The treatment of complicated type B aortic dissections with TEVAR has become a standard. Particularly, patients with true lumen collapse and malperfusion may benefit from a more aggressive treatment strategy including proximal TEVAR and distal bare-metal stent implantation to re-open the true lumen and to prevent distal stent-induced new entry. However, this study reports the challenges of this approach with a high rate of bare-metal stent fractures during the follow-up. The fractures that occurred at the site of vertical nitinol bridges led to the dissection membrane ruptures and the reperfusion of the false lumen with consecutive dilatation. A close follow-up is mandatory to detect this complication and to treat the patients with TEVAR extension.

Abnormal Wall Shear Stress Area is Correlated to Coronary Artery Bypass Graft Remodeling 1 Year After Surgery.

Coronary artery bypass graft surgery is a common intervention for coronary artery disease; however, it suffers from graft failure, and the underlying mechanisms are not fully understood. To better understand the relation between graft hemodynamics and surgical outcomes, we performed computational fluid dynamics simulations with deformable vessel walls in 10 study participants (24 bypass grafts) based on CT and 4D flow MRI one month after surgery to quantify lumen diameter, wall shear stress (WSS), and related hemodynamic measures. A second CT acquisition was performed one year after surgery to quantify lumen remodeling. Compared to venous grafts, left internal mammary artery grafts experienced lower abnormal WSS (< 1Pa) area one month after surgery (13.8 vs. 70.1%, p = 0.001) and less inward lumen remodeling one year after surgery (- 2.4% vs. - 16.1%, p = 0.027). Abnormal WSS area one month post surgery correlated with percent change in graft lumen diameter one year post surgery (p = 0.030). This study shows for the first time prospectively a correlation between abnormal WSS area one month post surgery and graft lumen remodeling 1year post surgery, suggesting that shear-related mechanisms may play a role in post-operative graft remodeling and might help explain differences in failure rates between arterial and venous grafts.

Inflammatory biomarkers are associated with changes in cerebral large artery thickness and lumen diameter in older adults

AbstractBackgroundAge‐associated remodeling of cerebral large arteries contributes to worse systemic and brain health in older adults. Vessel wall imaging (VWI) is a neuroimaging technique that offers the critical ability to quantify thickness and lumen diameter across arterial segments of the circle of Willis (CoW). Inflammation, a well‐known feature of aging, cerebrovascular disease, and Alzheimer’s disease, may be a central driver of age‐related changes in CoW morphology. We investigate if fluid biomarkers of inflammation predict key features of intracranial arterial aging, including CoW thickening and dilatation over time.MethodsVanderbilt Memory and Aging Project participants were studied (n=96, 73±7 years, 80% male, mean follow‐up=3.0 years). Baseline systemic inflammatory biomarkers (TNF‐α, IL‐6) were quantified from blood plasma samples. Baseline neuroinflammatory biomarkers (sTREM2, YKL‐40, MMP‐2, MMP‐3, MMP‐9) were quantified from cerebrospinal fluid samples. Intracranial artery lumen diameter and thickness were manually measured across the basilar artery (BA) and bilateral segments of the internal carotid artery (ICA), anterior cerebral artery (ACA), and middle cerebral artery (MCA) using serial VWI MRI. Linear mixed effects regressions related time x inflammatory biomarker (one predictor per model) to longitudinal VWI lumen diameter and thickness outcomes, adjusting for baseline age, sex, race/ethnicity, education, Framingham Stroke Risk Profile, cognitive status, apolipoprotein ε4 status, T1‐weighted intracranial volume, and time.ResultsHigher CSF sTREM2 levels related to faster luminal narrowing (right ACA, p‐value=0.001). Higher CSF YKL‐40 levels related to faster luminal narrowing (right ACA, p‐value=0.07). Lower CSF MMP‐2 levels related to faster wall thickening (left MCA, p‐value&lt;0.05). Lower CSF MMP‐3 levels related to luminal narrowing, while higher CSF MMP‐3 levels related to luminal widening (left ICA, p‐value=0.05). TNF‐α, IL‐6, and MMP‐9 were unrelated to any VWI changes (p‐values&gt;0.14).ConclusionResults suggest neuroinflammatory biomarkers are largely related to longitudinal intracranial artery narrowing and thickening. However, additional associations between MMPs and luminal widening may reflect the mixed nature of MMP activity on cerebrovascular remodeling. Immune responses mediated by astroglial and microglial activity as well as MMPs may be key pathophysiological mechanisms underlying age‐related cerebral arterial remodeling.

A Comparative Study of the Right and Left Carotid Arteries in Relation to Age for Patients With Diabetes and Hypertension

Introduction: Age, hypertension, and diabetes can cause significant alterations in arterial structure and function, including changes in lumen diameter (LD), intimal-medial thickness (IMT), flow velocities, and arterial compliance. These are also considered risk markers of atherosclerosis and cerebrovascular disease. A difference between right and left carotid artery blood flow and IMT has been reported by some researchers, and a difference in the incidence of nonlacunar stroke has been reported between the right and left brain hemispheres. The aim of this study was to determine whether there are differences between the right and left common carotid arteries and internal carotid arteries in patients with hypertension and diabetes for 2 age groups. Methods: We studied 250 patients with both diabetes and hypertension. Patients were divided into 2 age groups with the old age group being 56 to 75 years and the young age group 35 to 55 years. The bilateral common carotid and internal carotid arteries were evaluated with B-mode ultrasound and Doppler examinations. The LD and IMT were measured for both common carotid arteries, and spectral waveform parameters and indices were recorded for both internal carotid arteries. Results: The difference in LD between the left and right common carotid arteries for the old age group was 11.64% and for the young age group was 6.42%, with significant P values of &lt;.05 for both age groups. The difference in IMT between the left and right common carotid arteries was 18.27% in the old age group compared with 15.38% in the young age group, with significant P values of &lt;.05. There was a difference in peak systolic velocity between the left and right internal carotid arteries of 4.85% in the old age group which was not significant, compared with 14.28% in the young age group with a significant P value &lt;.05, whereas the difference in end-diastolic velocity between the left and right internal carotid arteries was not significant for both age groups. Differences between the right and left internal carotid arteries for resistive index, pulsatility index, and pressure gradient were significant only in the young age group. Conclusion: We found significant differences between the right and left common carotid and internal carotid arteries in patients with diabetes and hypertension which were more prominent in the young age group. Values for common carotid IMT and LD were significantly higher in the left common carotid artery versus the right common carotid artery in both age groups. Differences between the 2 carotid sides may be attributed to anatomic variations in the common carotid artery origins which lead to differences in stress between the 2 sides.

Distinct Temporal Pattern of the Prediction of Lumen Remodeling of Lower Extremity Vein Bypass Grafts by Initial Local Hemodynamics.

We predicted human lower extremity vein bypass graft remodeling by hemodynamics. Computed tomography and duplex ultrasound scans of 55 patients were performed at 1week and 1, 6, and 12months post-implantation to obtain wall shear stress (WSS) and oscillatory shear index (OSI) at 1-mm intervals via computational fluid dynamics simulations. Graft remodeling was quantified by computed tomography-measured lumen diameter changes in the early (1week-1month), intermediate (1-6months), and late (6-12months) periods. Linear mixed-effect models were constructed to examine the overall relationship between remodeling and initial hemodynamics using the average data of all cross sections within the same graft. A significant association of graft remodeling with WSS (p < 0.001) and time (p = 0.001) was found; however, the effect size decreased with time (every 2.7 dyne/cm2 increase of WSS was associated with a 0.39, 0.35, 0.002mm diameter increase in the three periods, respectively). The association of remodeling with OSI was significant only in the intermediate period (every 0.1 increase of OSI was associated with a 0.25mm lumen diameter decrease, p = 0.004). Therefore, the association of graft lumen remodeling with local hemodynamics has a distinct temporal pattern; WSS and OSI are predictive of remodeling only in certain postoperative periods.

Impact of myocardial bridge on non-culprit vessel lumen changes in patients with acute coronary syndrome.

This study aims to clarify the impact of myocardial bridge (MB) on the presence and progression of atherosclerosis in left descending coronary artery (LAD) in patients with acute coronary syndrome (ACS). Ninety-eight patients who underwent percutaneous coronary intervention with the diagnosis of ACS and follow-up coronary angiography but had no significant stenosis in the LAD were included. MB was defined based on coronary angiography. Quantitative coronary angiography was performed to determine the segments where MB was present and proximal to the MB (proximal segment) in patients with MB. In patients without MB, a corresponding region was quantitatively analyzed. The primary endpoint was changes in minimum lumen diameter (MLD) and percentage of diameter stenosis (%DS) in the proximal segment from baseline to follow-up angiography, namely ΔMLD and Δ%DS. MB was identified in 29 (29.6%) patients. Patients with MB had larger MLD and smaller %DS in the proximal segment than their counterpart. During the mean follow-up period of 12.9 ± 5.7months, MLD and %DS in the proximal segment did not change significantly from baseline to follow-up in patients with and without MB. No significant between-group differences were observed in ΔMLD and Δ%DS. Baseline MLD was identified as the only factor associated with ΔMLD in the proximal segment. ACS patients who had MB but no significant stenosis in the LAD had larger MLD and smaller %DS at the segment proximal to MB compared to those without. In this selected population, serial lumen changes assessed by ΔMLD were not associated with the presence of MB in the LAD.

Abstract 312: Periadventitial Lysyl Oxidase Inhibition Using Electrospun Nanofibers Improves Arteriovenous Fistula Maturation

Introduction: Arteriovenous fistula (AVF) nonmaturation is associated with postoperative fibrosis and an increase in lysyl oxidase (LOX) expression. Objective: The purpose of this study was to determine whether unidirectional periadventitial delivery of β-aminoproprionitrile (BAPN) using bilayer poly lactic-co-glycolic acid nanofiber scaffolds is a feasible approach to reduce AVF fibrosis and encourage adaptive vascular remodeling. Methods: AVFs were created in thirty Sprague Dawley rats (200-350 g) of both sexes by an end-to-side anastomosis of the epigastric vein to the femoral artery. BAPN-loaded (b-BAPN) (n=10) or vehicle (b-VEH) (n=10) scaffolds (5 mm x 5 mm) were wrapped around the juxta-anastomotic zone of the epigastric vein immediately after anastomosis. AVFs without treatment were used as an additional control (n=10). Changes in lumen diameter were followed-up weekly using ultrasound. Flow was calculated using the pulse-wave velocity and lumen diameter. AVFs were collected at 21 days for histomorphometric analysis and to assess fibrosis. Results: b-BAPN significantly increased dilation of AVFs at day 14 (185.9%) compared to b-VEH (135.5%; p=0.0006) and control AVFs (113.6%; p&lt;0.0001). The treatment (214.2%) had a significant difference compared to b-VEH (135.5%; p&lt;0.0001) and AVF controls (122%; p&lt;0.0001) at day 21 as well. In addition, blood flow was significantly enhanced in the treatment group (38.13 mL/min) versus b-VEH (9.436 mL/min; p=0.0002) and AVF controls (16.11 mL/min; p&lt;0.0001). Histomorphometric analysis confirmed the ultrasound findings. Treatment with b-BAPN significantly increased lumen area compared to control AVFs (354,127 μm 2 vs. 95,580 μm 2 ; p=0.0048). While there was no difference in intimal growth (p=0.5460), b-BAPN significantly reduced luminal occlusion with respect to control AVFs (0.0611 vs. 0.2067; p=0.0002). Finally, b-BAPN (49.48%) significantly reduced the fibrosis percent area compared to b-VEH (72.14%; p=0.0016) and control AVFs (74.5%; p=0.0007). Conclusion: Periadventitial LOX inhibition prevents AVF postoperative fibrosis and promotes adaptive vascular remodeling.

Intraluminal Pressure, Multi‐Dimensional Field Imaging and Fluid Volume Recordings as a Useful Tool to Determine Peristaltic Propulsion

IntroductionPeristalsis is a collective process of intestinal muscle contractions for the passage of food through the gastrointestinal tract. Although, peristalsis has been extensively studied using spatiotemporal mapping and pressure transducers both in vivo and in vitro, the quantitative analysis of peristaltic propulsion is not fully understood. Lack of a definitive tool therefore, limited drug discovery in the field of constipation including IBSC. In this study, we used directional lighting, advanced field‐imaging techniques together with intraluminal pressure recordings to determine intestinal diameter, frequency of longitudinal muscle activity and pressure changes as well as velocity of anterograde and retrograde contractions and volume output measurements to help determine the net peristaltic activity.MethodsThe basal activity of intestinal peristalsis in terms of intraluminal pressure (ILP) changes, real‐time changes in longitudinal muscle activity and intestinal lumen diameter were measured in approximately 5 cm long segments from jejunum of mouse small intestine (male, NIH Swiss) in physiological Ringer solution. Intraluminal pressure was recorded using pressure transducers connected to the oral and aboral end of each segment mounted in Perfusion Bath for Tubular Organs, (Harvard apparatus, USA). Longitudinal muscle activity was studied using CVX400 series vision system, and LumiTrax™multi‐spectrum light (Keyence, USA) using multiple tracking points in each intestinal segment. The number, strength, and amplitude of oscillations in terms of intraluminal pressure changes and longitudinal muscle activity was analyzed using custom written programs. Luminal volume output was measured using a photo‐electric drop counter unit.ResultsThe number, amplitude, duration, and frequency of high and low amplitude changes in ILP and longitudinal muscle activity was determined using a lab‐written program. The frequency of longitudinal muscle activity correlated well with the frequency of low and high amplitude pressure changes. Frequency of both these oscillations were found to be 0.7 Hz. A reduction in the ILP was found to induce high amplitude contractions which subsided as the ILP increased. Changes in intestinal diameter with time correlated to ILP changes. A reduction in luminal diameter caused an increase in ILP and when not fully compensated caused increased fluid output. The mean velocity of the contractions over time in the regions tracked was determined to be 2.5 – 2.7mm/sec with peak anterograde contraction velocity of ‐4.06 mm/sec and retrograde contractions of 12 mm/sec. This mean velocity in presence of physiological Ringer solution was thought to determine the direction of contractions along the length of the GI tract under normal conditions.InferenceFrequency of longitudinal muscle activity and ILP oscillation showed similar frequency suggesting common pacemaker activity. The velocity of the contraction and volume output over time will help determine the overall peristaltic movement and could be used as a helpful index to gauge constipation.

Late Outcomes of Transcatheter Coarctation Intervention in Infants with Biventricular Anatomy.

Determine outcomes of catheter intervention for aortic coarctation in infants. Aortic coarctation in infants following surgical repair and in high surgical risk native cases remains a challenging problem. Catheter intervention is an alternative to surgical intervention. Single-center, chart review of infants with biventricular anatomy who underwent coarctation stent placement or balloon angioplasty between 04/2004 and 04/2020. Outcomes of interest included change in aortic lumen diameter, peak gradient, number of re-interventions, time to re-intervention, and adverse events. Thirty-four patients were included in analysis, of those 16 underwent stent placement. Patients' mean age was 4.0 ± 3.0months and weight of 5.3 ± 1.9kg. Follow-up interval was 5.4 ± 5.1years (0.2-16.1years). Twelve (35%) patients underwent procedure due to ventricular dysfunction; the rest were for high resting gradient. Coarctation diameter increased from 2.4 ± 1.0 to 4.5 ± 1.3 (p < 0.01) and gradient decreased from 32.0 ± 18.4mmHg to 9.2 ± 8.8mmHg (p < 0.01). Thirteen (81%) of the stented patients required at least one re-intervention, at an average of 1.7 ± 3.2years from the index procedure. Five (28%) of those undergoing balloon angioplasty required repeat intervention. There was no mortality due to the procedure and one late mortality. One patient had a serious procedural adverse event. On follow-up, 12 (35%) were on anti-hypertensive medications. Catheter intervention, including stent placement, for aortic coarctation in infants is feasible with an acceptable adverse event profile. Repeat interventions are common.

Modeling and Predicting Blood Flow Characteristics through Double Stenosed Artery from Computational Fluid Dynamics Simulations using Deep Learning Models

Establishing patient-specific finite element analysis (FEA) models for computational fluid dynamics (CFD) of double stenosed artery models involves time and effort, restricting physicians’ ability to respond quickly in time-critical medical applications. Such issues might be addressed by training deep learning (DL) models to learn and predict blood flow character-istics using a dataset generated by CFD simulations of simplified double stenosed artery models with different configurations. When blood flow patterns are compared through an actual double stenosed artery model, derived from IVUS imaging, it is revealed that the sinusoidal approximation of stenosed neck geometry, which has been widely used in previous research works, fails to effectively represent the effects of a real constriction. As a result, a novel geometric representation of the constricted neck is proposed which, in terms of a generalized simplified model, outperforms the former assumption. The sequential change in artery lumen diameter and flow parameters along the length of the vessel presented opportunities for the use of LSTM and GRU DL models. However, with the small dataset of short lengths of doubly constricted blood arteries, the basic neural network model outperforms the specialized RNNs for most flow properties. LSTM, on the other hand, performs better for predicting flow properties with large fluctuations, such as varying blood pressure over the length of the vessels. Despite having good overall accuracies in training and testing across all the properties for the vessels in the dataset, the GRU model underperforms for an individual vessel flow prediction in all cases. The results also point to the need of individually optimized hyperparameters for each property in any model rather than aiming to achieve overall good performance across all outputs with a single set of hyperparameters.

Histomorphometry of the Duodenum of Ducks (Anas platyrhyncos) after Administration of Nanochitosan in Feed

Poultry farming business has several problems such as lack of availability on raw materials, expensive feed prices, and egg production that is not optimal. To overcome the problem of high feed prices and duck productivity, we need to add feed additives such as nanochitosan. Poultry farming business has several problems such as lack of availability on raw materials, expensive feed prices, and egg production that is not optimal. To overcome the problem of high feed prices and duck productivity, we need to add feed additives such as nanochitosan. This study aimed to analyze the effect of nanochithosan feed on the digestive function of the intestine tenue (duodenum) as indicated by histomorphometric changes in the duodenum of Tegal ducks (Anas platyrhyncos). Duodenal histomorphometry related to digestive function was measured, including changes in lumen diameter, villi height, epithelial cell thickness, and muscular layer thickness. This study used a completely randomized design consisting 5 treatments with 5 replications. The research treatments included P0 as control (basic feed without nanochitosan particle additives) and P1, P2, P3, and P4 (basic feed with the addition of nanochitosanwith the doses of 2.5; 5; 7.5; and 10 grams/kg feed respectively). The variables observed were lumen diameter, villi height, epithelial layer thickness, and duodenal muscle layer thickness. The research data were analyzed using the analysis of variance (ANOVA) with a 95% confidence level. The results showed that the addition of nanochitosan particles in the feed had a significant effect on the lumen diameter and thickness of the duodenal muscular layer (P0.05). Tegal ducks. The conclusion of this study is that nanochitosan feed additives with a concentration of 2.5-10% can improve digestive function and improve duodenal histomorphometry in the intestine tenue of Tegal ducks as indicated by an increase in lumen diameter, villi height, and the thickness of epithelial cell thickening, and muscular layer. The novelty from this study is the production and the used of nanochitosan as feed additive to repair histomorphometry of duodenum in intestine tenue of Tegal ducks. From this research, people gets benefit by knowing the use nanochitosan as feed additive to improve digestion performance and productivity of Tegal ducks.

Imaging Identification and Prognosis of the Distal Internal Carotid Artery With Near and Complete Occlusion After Recanalization.

Background and Purpose: Previous studies have mainly focused on treatment strategies and clinical outcomes for internal carotid artery near occlusion (ICANO) and internal carotid artery complete occlusion (ICACO). However, reports on the morphological changes of distal internal carotid artery (ICA) after recanalization are scarce. This study aimed at illustrating identifying features, assessing prognosis of the distal ICA after recanalization, and exploring best practices for treatment for ICANO and ICACO.Materials and Methods: We retrospectively studied the clinical characteristics of 57 patients with ICANO or ICACO who underwent surgical recanalization. The clinical data, angiographic morphology, technical successful rate, perioperative complications, and the lumen changes of distal ICA before and after successful recanalization were analyzed.Results: Fifty-two patients who achieved successfully recanalization were studied. Based on the postoperative lumen diameter changes in the distal ICA, 19 cases were classified as distal-dilatation and the remaining 33 as distal-narrowness. Patients in the distal-narrowness group mostly had ICACO (21.1 vs. 54.5%) and were men (68.4 vs. 93.9%). In the distal-narrowness group, the lumen of the distal ICA recovered to normal in 32 of the 33 patients during the follow-up period. Of the 32 patients reviewed, the ICA of 28 patients dilated back to normal after 1 week of surgery; the ICA of remaining patients 4 dilated 2 weeks postoperatively.Conclusions: Narrowness of the distal ICA after hybrid recanalization was more prevalent in male patients with ICACO. Homogeneous stenosis of the whole course of the distal ICA is a low-perfusion narrowness which does not require intervention and will spontaneously recover after successful recanalization with an increase in the forward flow.

Longitudinal Evolution of Pulmonary Artery Wall Shear Stress in a Swine Model of Pulmonary Artery Stenosis and Stent Interventions.

Branch pulmonary artery stenosis (PAS) commonly occurs in congenital heart disease and it has previously been hypothesized that in branch PAS the pulmonary arteries (PAs) remodel their lumen diameter to maintain constant wall shear stress (WSS). We quantified the longitudinal progression of PA WSS in a swine model of unilateral PAS and two different intervention time courses to test this hypothesis. To quantify WSS in the entire pulmonary tree we used 4D Flow MRI for the large-proximal PAs and a structured tree model for the small-distal PAs. Our results only partially supported the hypothesis that in branch PAS the PAs remodel their lumen diameter to maintain WSS homeostasis. Proximal PA WSS was similar between groups at the final study time-point but WSS of mid-sized (5mm to 500μm) PA segments was found to be different between the sham and LPAS groups. This suggests that WSS homeostasis may only be achieved for the large-proximal PAs. Additionally, our results do not show WSS homeostasis being achieved over shorter periods of time suggesting that any potential WSS dependent changes in PA lumen diameter were a long-term remodeling response rather than a short-term vasodilation response. Future studies should confirm if these findings hold true in humans and investigate the impacts of WSS at different levels of the pulmonary tree on growth.

In-situ quantification of microscopic contributions of individual cells to macroscopic wood deformation with synchrotron computed tomography

Wood-based composites hold the promise of sustainable construction. Understanding the influence on wood cellular microstructure in the macroscopic mechanical behavior is key for engineering high-performance composites. In this work, we report a novel Individual Cell Tracking (ICT) approach for in-situ quantification of nanometer-scale deformations of individual wood cells during mechanical loading of macroscopic millimeter-scale wood samples. Softwood samples containing > 104 cells were subjected to controlled radial tensile and longitudinal compressive load in a synchrotron radiation micro-computed tomography (SRµCT) setup. Tracheid and wood ray cells were automatically segmented, and their geometric variations were tracked during load. Finally, interactions between microstructure deformations (lumen geometry, cell wall thickness), cellular arrangement (annual growth rings, anisotropy, wood ray presence) with the macroscopic deformation response were investigated. The results provide cellular insight into macroscopic relations, such as anisotropic Poisson effects, and allow direct observation of previously suspected wood ray reinforcing effects. The method is also appropriate for investigation of non-linear deformation effects, such as buckling and deformation recovery after failure, and gives insight into less studied aspects, such as changes in lumen diameter and cell wall thickness during uniaxial load. ICT provides an experimental tool for direct validation of hierarchical mechanical models on real biological composites.

Fate of lumen size in distal coronary segment following successful chronic total occlusion recanalization

BackgroundRestoration of anterograde blood flow leads to alterations in vascular wall stress that may influence lumen size distal to chronic total occlusion (CTO) lesions. We sought to assess changes in lumen diameter of segments distal to the stent segment of successfully recanalized CTO. MethodsWe analyzed 507 consecutive CTO cases with stent implantation that underwent follow-up angiography at a single high-volume center (mean follow-up of 13.5 months). Segments ≤40 mm distal to the stent edge were analyzed using quantitative coronary angiography. ResultsAt follow-up, lumen diameters significantly increased; diameter changes of 0.26 ± 0.47 (percent diameter change of 18.2%) at 5 mm distal, mean lumen diameter changes of 0.23 ± 0.35 (14.3%) and minimal lumen diameter changes of 0.22 ± 0.80 (24.7%) (all p < 0.001). Lumen enlargement was similar between visually shrunken and stenosed vessels (degree of stenosis ≥20% with luminal irregularities) distal to stents; 5 mm distal (0.32 ± 0.48 vs. 0.30 ± 0.48, p = 0.76), mean lumen diameter changes (0.26 ± 0.37mm vs. 0.26±0.33 mm, p = 0.94), minimal lumen diameter changes (0.28 ± 0.43 mm vs. 0.22 ± 1.30 mm, p = 0.48). There was no association between degree of in-stent narrowing and changes in distal lumen diameter (Spearman r = −0.02, p = 0.59). Multivariate logistic regression for the predictors of greater lumen enlargement indicated that patients with left ventricle dysfunction (ejection fraction ≤45%) had greater enlargement [odds ratio (OR): 2.53, 95% confidence interval (CI): 1.23–5.23, p = 0.01]. Conversely, a low hematocrit (male <40%, and female <35%) was associated with attenuated lumen enlargement (OR: 0.68 95% CI: 0.47–0.98; p = 0.04). ConclusionsLumen diameter distal to CTO lesions significantly increased following successful revascularization, regardless of diseased status of the distal bed or degree of in-stent narrowing. These findings implicate appropriate determination of stent size, stent coverage length, as well as management strategies of distal vessels.

Clinical and Morphologic Outcomes of Endovascular Repair for Subacute and Chronic Type B Aortic Dissection

The objective of the study was to assess long-term remodeling, survival, and reintervention outcomes after thoracic endovascular aortic repair (TEVAR) for subacute and chronic type B aortic dissection (TBAD). All patients who underwent TEVAR for subacute or chronic TBAD at a tertiary referral center between 1999 and 2015 were included in this cohort study. The primary outcome was aortic remodeling, and secondary outcomes included survival, rate of major complications, and reinterventions. Fifty patients were included, with mean age of 62.4years, 10 (20%) DeBakey type IIIA and 40 (80%) DeBakey type IIIB dissection; 45 standard TEVAR, 2 branched TEVAR, 3 TEVAR combined with fenestrated or branched EVAR. Indication for TEVAR was intact (n=40) or ruptured (n=1) postdissection aneurysm, hypoperfusion (n=4), treatment-refractory pain (n=2), or a combination (n=3). Mean clinical follow-up was 76months, and median radiological follow-up was 46months. Thirty-day survival was 96%, stroke 4%, renal failure 0%, paraplegia 0%. Three- and five-year survival was 92% (95% confidence interval (CI) [79; 97]) and 77% (95% CI [61; 87]), respectively. Of 19 late deaths, 6 were confirmed aorta related. Five-year freedom from reintervention was 69% (95% CI [53-80]). Distal stent graft extension due to aortic dilatation composed most reinterventions. Mean maximal aortic diameter was 58.7mm preoperatively and 51.9mm on last follow-up (P=0.003). On thoracic level, true lumen expanded (+10.0mm, 95% CI [6.4; 13.6]) (P<0.001) and false lumen decreased (-11.9mm, 95% CI [-15.2; -8.5]) (P<0.001) from baseline to the last computed tomography. In the abdominal aorta, true lumen diameter change was +3.1mm (95% CI [1.4; 4.8]) (P=0.001); false lumen diameter change was +1.0mm (95% CI [-1.8; 3.8]) (P=0.464). TEVAR for subacute and chronic TBAD results in favorable remodeling of the thoracic but not the abdominal aorta. Five-year survival is almost 80%, but late aortic deaths still occur. Aortic dilatation distal to the treated segment requiring reintervention is common, emphasizing the importance of follow-up.

Co‐Presentation of a Circumflex Retroesophageal Right Aortic Arch and Persistent Left Superior Vena Cava in a Human Cadaver

The present study concerns a unique finding of two cardiovascular anomalies in a 57 y.o. human female Caucasian cadaver whose death was determined as non‐cardiovascular. She presents with a circumflex retroesophageal right aortic arch (CReRAA) that gives rise to an aberrant left subclavian artery from a diverticulum of the proximal descending aorta. A left ligamentum arteriosum completes a vascular ring with the CReRAA around her trachea and esophagus. She also presents with persistent left superior vena cava (PLSVC) amid regular right superior vena cava (SVC) (i.e., double SVC) with an innominate vein bridging the two. Her PLSVC leads to a dilated coronary sinus coursing the posterior left coronary sulcus to the right atrium. Albeit separately rare anomalies, simultaneous presentation of CReRAA and PLSVC appears to be unrecorded. The objective of the present study is to assemble a comprehensive case report illustrating gross presentation, embryological explanation, histological examination, and clinical considerations of the CReRAA co‐presenting with PLSVC.Gross presentation of the CReRAA and PLSVC was compared to anatomical norm, and embryological explanations for the anomalies were hypothesized. Cross‐sectioned segments of the trachea, esophagus, and coronary sinus were examined grossly and histologically for anomalous changes in lumen diameter and tissue integrity.Embryologically, CReRAA is caused by left 4th branchial arch regression with right dorsal aorta persistence. As a result, the right 4th branchial arch becomes the aortic arch giving off its typical branches in reverse succession before branching an aberrant left subclavian artery from the vestige of the distal left dorsal aorta (Kommerell’s diverticulum) at the proximal descending aorta. The left 6th branchial arch regresses to form ligamentum arteriosum. PLSVC results from a persisting caudal portion of the left anterior cardinal vein which normally regresses as the ligament of Marshall to separately form the coronary sinus. Gross measurements reveal tracheoesophageal constriction from the CReRAA vascular ring and coronary sinus dilation from the PLSVC. Histological analysis of the tracheoesophageal and coronary sinus tissues has yet to be performed.This case report substantiates known clinical implications of CReRAA and PLSVC in new light of being co‐presented. Complete vascular rings can be challenging to identify since their atretic components are not fillable with contrast medium and present serious clinical sequelae (chiefly respiratory distress and esophageal dysphagia) from tracheoesophageal compression. As such, CReRAA should be a differential diagnosis when these otherwise unexplained symptoms occur. Additionally, PLSVC has important implications for placing cardiovascular implantable electronic device (CIED) transvenous leads through the right SVC via the left subclavian vein. When encountered, alternative access through the PLSVC and into the heart via the coronary sinus or right subclavian venous access should be considered. Increasing available knowledge of such anomalies benefits both physicians and patients.

Sequential multidetector computed tomography assessments after venous graft treatment solution in coronary artery bypass grafting

ObjectivesTo assess the effect of DuraGraft (Somahlution Inc, Jupiter, Fla), an intraoperative graft treatment, on saphenous vein grafts in patients undergoing isolated coronary artery bypass grafting. MethodsWithin patients, 2 saphenous vein grafts were randomized to DuraGraft or heparinized saline. Multidetector computed tomography angiography at 1, 3, and 12 months assessed change in wall thickness (primary end point at 3 months), lumen diameter, and maximum narrowing for the whole graft and the proximal 5-cm segment. Safety end points included graft occlusion, death, myocardial infarction, and repeat revascularization. ResultsAt 3 months, no significant changes were observed between DuraGraft- and saline-treated grafts (125 each) for wall thickness, lumen diameter, and maximum narrowing. At 12 months, DuraGraft-treated grafts demonstrated smaller mean wall thickness, overall (0.12 ± 0.06 vs 0.20 ± 0.31 mm; P = .02) and in the proximal segment (0.11 ± 0.03 vs 0.21 ± 0.33 mm; P = .01). Changes in wall thickness were greater in the proximal segment of saline-treated grafts (0.09 ± 0.29 vs 0.00 ± 0.03 mm; P = .04). Increase in maximum graft narrowing was larger in the proximal segment in the saline-treated grafts (4.7% ± 12.7% vs 0.2% ± 3.8%; P = .01). Nine DuraGraft and 11 saline grafts had occluded or thrombosed. One myocardial infarction was associated with a saline graft occlusion. No deaths or revascularizations were observed. ConclusionsDuraGraft demonstrated a favorable effect on wall thickness at 12 months, particularly in the proximal segment. Longer-term follow-up in larger studies is needed to evaluate the effect on clinical outcomes.

Heterogeneous and dynamic lumen remodeling of the entire infrainguinal vein bypass grafts in patients

ObjectiveTo examine the regional variation and temporal change in lumen size along the entire autogenous vein bypass graft used for treating arterial occlusive disease in lower extremity and to explore the factors associated with graft expansive or constrictive remodeling. MethodsPatients were prospectively scanned using contrast-enhanced computed tomography at 1 week and 1, 6, and 12 months postoperatively to obtain lumen cross-sectional areas at 1-mm intervals along the entire grafts. Graft lumen remodeling characteristics and the associated demographic and clinical factors were examined. ResultsFifty-six patients with at least two consecutive computed tomography scans were analyzed. Patients with a composite or longer graft, or with diabetes, had a larger lumen cross-sectional area variation along the graft. The mean lumen cross-sectional areas of all the grafts demonstrated no significant changes through 12 months. However, individually, graft remodeling was time dependent and there was a more dramatic change in lumen cross-sectional area within the first postoperative month. At 12 months, a near equal distribution between expansive and constrictive grafts existed. A negative relation between the initial lumen diameters and the subsequent lumen diameter changes was observed. Eleven grafts failed within 12 months; failed and patent grafts had similar mean lumen cross-sectional areas at all four time points, but failed grafts had a larger maximal local cross-sectional area reduction from 1 week to 1 month (58.0 ± 6.7% vs 38.1 ± 3.1%, mean ± standard error of the mean, failed vs patent, P = .004). Black patients had a smaller mean lumen cross-sectional area than white patients at all four time points and also had a higher early percent mean area reduction (−20.5 ± 6.3% vs −1.0 ± 3.7%, black vs white, P = .018). Cilostazol use was associated with early expansive graft remodeling. ConclusionsVein grafts remodel heterogeneously and dynamically. Remodeling is associated with initial graft lumen size, race, and cilostazol use. It is found that remodeling that produces some critical minimum area or maximal percent reduction during the first postoperative month may predispose to vein graft failure. These findings offer insight into further investigation to examine the underlying mechanisms and opportunities to improve graft remodeling and durability.