Stenotic Site Research Articles

NUMERICAL ANALYSIS OF BALLOON EXPANDABLE STENT DEPLOYMENT INSIDE A PATIENT-SPECIFIC STENOTIC CORONARY ARTERY TO INVESTIGATE THE INSTANT MECHANICAL BEHAVIORS

The instant mechanical behaviors of stenotic coronary artery and deployed stents have significant impacts on percutaneous coronary intervention prognosis. However, they could not be obtained directly from the current examination techniques, which are commonly used in clinical practice. Thus, we intend to investigate the instantaneous mechanical behaviors of deployed stent and artery through virtually stenting technology based on a real clinical case in assessment of geometric and biomechanical characteristics. Method: Finite element analysis models, including rigid guide catheter, six-folded balloon with conical tip, crimped and bended stent, stenotic coronary artery with soft plaques, were simulated through virtual mechanical expansion and recoil procedure. The morphology changes of coronary lumen, strain and stress distribution of involved components at different stages and apposition of stent struts were analyzed. Results: Lumen in the stenotic region restored patency obviously at maximum expansion and had an elastic recoil about 13.5% later. The maximum principal stress distribution of artery walls and plaque was mainly concentrated in the stenotic segment with the peak value of 1.252[Formula: see text]MPa and 2.975[Formula: see text]MPa at max expansion, 0.713[Formula: see text]MPa and 1.25[Formula: see text]MPa after recoil, respectively. The higher von Mises stress and plastic equivalent strain of stent were present at the bended strut and inter-ring connectors with the peak value of 714.2[Formula: see text]MPa and 0.2385 at max expansion, 694[Formula: see text]MPa and 0.2276 after recoil. Slight malappositions were found in the proximal segment and struts distribution in the stenotic sites showed certain asymmetry. Conclusion: The instant mechanical behaviors of artery and stent could be evaluated through virtual stenting approach in assessment of geometric and biomechanical characteristics. This may contribute to choosing the best stenting schemes and predicting the clinical outcomes for a specific patient.

A new formula for predicting the position of severe arterial stenosis

Noninvasive location of an occlusion or a severe stenosis in the arterial system is of a great interest for surgical interventions. Here, we present a new method to determine the location of arterial 99% stenosis in the arterial (sub) system. The method requires a measurement of propagation constant and the instantaneous flow rate or velocity at two sites of an arterial tree. The method was successfully tested using Womersley’s oscillatory flow theory and the data obtained by a simulation of Fluid structure interaction (FSI). The effect of noise has been investigated to simulate experimental conditions. The results demonstrate that location of 99% severe stenosis could be accurately obtained. The spatial resolution was approximately a few centimeters and the differences between exact and computed values didn’t exceed 13%. However, the identifications of stenotic sites decreased with the distance. Further investigation of the developed method in vivo and in vitro is required.

Radiologists need to be aware of secondary central venous stenosis in patients with SAPHO syndrome.

We aimed to define central venous stenosis (CVS) caused by sternocostoclavicular hyperostosis as a feature of synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome on routine contrast-enhanced computed tomography (CT) images. The relationship between SAPHO syndrome and CVS without venous thrombosis caused by anterior chest wall compression has not been investigated. Therefore, the present study evaluated CVS in patients with SAPHO syndrome at our hospital. We retrospectively reviewed contrast-enhanced CT images of ten patients with suspected or diagnosed SAPHO syndrome between January 2007 and November 2015. The patients were assessed by contrast-enhanced CT using 16-, 64- or 128-detector row scanners. Two radiologists independently assessed the presence of CVS or obstruction and SAPHO syndrome in a retrospective review of CT images. Six of the ten patients had findings of CVS with SAPHO syndrome. The mean diameter and patency rate at the site of CVS were 1.88mm and 27.2%, respectively. Stenosis was more significant in terms of the mean diameter of CVS sites than of stenotic sites that crossed the anteroposterior vein (p < 0.05). Radiologists who routinely assess contrast-enhanced CT images should be aware that sternocostoclavicular hyperostosis with SAPHO syndrome could cause secondary CVS. • SAPHO syndrome can cause central venous stenosis. • Radiologists should consider central venous stenosis in patients with SAPHO syndrome. • Early diagnosis of central venous stenosis due to SAPHO syndrome is challenging.

Wall shear stress and velocity distributions in different types of stenotic bifurcations

Blood flow following Carreau-Yasuda viscosity model at steady-state through various categories of stenotic arterial bifurcations based on Movahed [1] was investigated by using finite element method. Reynolds number was fixed at 233. Results are reported in terms of Wall shear stress (WSS) and velocity distributions. The maximum peaks of WSS were found at the minimum flow area, where high velocities were present. Symmetric stenotic sites give rather symmetric WSS distribution and symmetric velocity profile, whereas on asymmetric sites, the skewness depends upon the presence of the stenotic site as it introduces curvature. Volumetric flow rate ratios at various locations were introduced to indicate the crucial conditions. In addition, levels of stenosis between 30-60 % based on flow area were considered. The 60 % level gave significantly higher WSS peak and the lowest WSS at the location behind the stenosis for the symmetric case. For the asymmetric case, the 50 and 60 % levels show the lowest WSS values at the end of the stenotic site.

Should We Be Concerned? Comparison of Catheter and CT Angiogram for Arterial Distensibility at the Site of Carotid Stenosis during Catheter Angiography

Purpose: During catheter angiogram (CA) there is momentary increase in intravascular volume and pressure due to intra-arterial injection that can potentially cause vascular distention at the stenotic site, whereas on CT angiogram (CTA) is unlikely due to intravenous administration. Methods: CA and CTA of the carotid artery from 29 patients were retrospectively studied. CA and CTA were obtained for each patient. Curved sagittal MPRs mirroring the carotid artery on CA were used to measure the diameter at stenosis and at the distal lumen. Mural plaque calcium content was graded on axial CTAs. Results: Accounting for repeated measurements, the likelihood that the lumen diameter from CA will be larger than CTA was higher at stenosis than distal to it but the difference in lumen diameters at stenosis was similar to CTA. There is insufficient evidence that intra-arterial hand-injection during CA leads to underestimation of the degree of stenosis. Percentage stenosis using the NASCET criteria differed between the 3 measurements, post hoc analysis showed significant difference between CA and axial CTA (p 0.99). The difference in lumen diameter did not depend on our calcium grading (p = 0.484). Conclusions: There is insufficient evidence to suggest that intra-arterial hand-injection contributes to vessel distention and underestimation of percent stenosis during CA in this study. Mural plaque calcium does not affect the degree of stenosis on CTA.

Shear Stress-sensitive Carriers for Localized Drug Delivery.

Stenosis of the critical blood vessels, which occurs in a variety of cardiovascular and cerebrovascular diseases, is one of leading causes of death in the world. Vascular stenosis will significantly alter the hemodynamic features in the vessel. Hemodynamic shear stress, one of the most important physical parameters of blood flow, will be dramatically elevated at the stenotic site. When platelets flow through the constricted site, they will sense these abnormally high shear stresses, and then respond by activating, sticking to the vascular wall, and aggregating at these sites. The shear-dependent platelet activation inspired a novel targeting platform-shear stress activated drug targeting delivery. The shear-activated drug delivery systems preferentially release their content under elevated shear stress, providing a novel approach to cure various diseases, in particular, cardiovascular diseases. In this review, we, on one hand, introduced the features of hemodynamic shear stress under both physiological and pathological conditions. On the other hand, we summarized the carriers displaying sensitivity to shear stress, such as liposomes, aggregations, gels, emulsions, in addition to the factors affecting the mechanical properties of them. Lastly, the clinical applications and prospects of this novel drug targeting strategy were discussed. It is hoped that, with a better understanding of shear stress-sensitive carriers and their targeted principle, a novel targeted drug delivery strategy will be one day applied in the clinics of the future.

Relationship between dyslipidemia and vascular repair after cervical artery dissection

AbstractBackgroundIn some cases of cervical artery dissection, vascular repair subsequently occurs at the stenotic or occluded sites. The factors responsible for this type of vascular repair remain unknown, but some reports from in vitro and animal models suggest that it is related to lipid metabolism.AimIn the present study, we investigated the relationship between vascular repair and dyslipidemia in cervical artery dissection.MethodsPatients with internal carotid artery and vertebral artery dissection who were admitted between April 2012 and March 2015 were included. Vascular repair was evaluated using magnetic resonance angiography. All patients were treated conservatively using antihypertensive and antiplatelet drugs, and also with statins in the presence of dyslipidemia. In this study, we investigated the relationship between vascular repair and dyslipidemia in cervical artery dissection.ResultsVascular repair was observed in 34 out of 55 patients (61.8%, repair group). Total cholesterol (203 mg/dL in repair group vs 225 mg/dL in non‐repair group), low‐density lipoprotein cholesterol (119 mg/dL vs 140 mg/dL), low‐density lipoprotein cholesterol/high‐density lipoprotein cholesterol ratio (2.09 vs 2.74) and triglycerides (117 mg/dL vs 154 mg/dL) were significantly negatively correlated with vascular repair. However, statin use was not significantly related to this type of repair.ConclusionsWe showed a relationship between vascular repair after cervical artery dissection and dyslipidemia. As cervical artery dissection often occurs at a relatively young age, vascular repair and the management of dyslipidemia are important issues to consider for the prevention of arteriosclerotic cerebrovascular diseases in later life.

Impact of optical coherence tomography- and coronary angioscopy-assessed neointimal tissue characteristics on occurrence of periprocedural myonecrosis in patients with in-stent restenosis.

Several characteristics of neointimal tissues, including neoatherosclerotic progression, have been reported in lesions with in-stent restenosis (ISR). However, the effects of these characteristics on outcomes after percutaneous coronary intervention (PCI) for ISR lesions remain unclear. We assessed the relationships between neointimal tissue characteristics and the occurrence of periprocedural myonecrosis (PMN) after PCI in ISR lesions. We investigated 72 ISR lesions in 72 patients with stable angina pectoris (SAP) who underwent pre- and post-revascularization optical coherence tomography (OCT) and coronary angioscopy (CAS). All lesions were classified as with PMN, defined by an elevated peak high-sensitivity cardiac troponin-T level during the 24-h post-PCI period, and without PMN. PMN was observed in 23 (31.9 %) lesions. PMN lesions had higher frequencies of OCT-derived thin-cap fibroatheroma (26.1 vs. 6.1 %, P = 0.03), CAS-derived intensive yellow neointima (30.4 vs. 10.2 %, P = 0.04), neointima with complex surface (60.9 vs. 28.6 %, P = 0.01), and CAS-derived atheromatous appearance (CAS-AAP), defined as yellow plaque including complex thrombi underneath disrupted neointimal coverage after ballooning (47.8 vs. 16.3 %, P = 0.008) at the most stenotic sites inside stents, compared to lesions without PMN. Multivariate logistic regression analysis identified CAS-AAP (odds ratio: 3.568, 95 % confidence interval: 1.109-11.475, P = 0.033) as an independent predictor of PMN. For ISR lesions in SAP patients, an OCT- and CAS-based assessment of neointimal tissue characteristics might help to predict the occurrence of PMN.

Fractional flow reserve-guided coronary angioplasty using paclitaxel-coated balloons without stent implantation: feasibility, safety and 6-month results by angiography and optical coherence tomography

BackgroundPercutaneous coronary interventions (PCI) with drug-coated balloons (DCB) might be a promising trade-off between balloon angioplasty and drug-eluting stents, since DCB inhibit neointimal proliferation and limit duration of dual antiplatelet therapy. We investigated the safety, feasibility, and 6-month results of fractional flow reserve (FFR)-guided use of the paclitaxel-coated SeQuent Please® balloon without stenting for elective PCI of de novo lesions.Methods and resultsIn 46 patients (54 lesions) with stable symptomatic coronary artery disease (CAD), a FFR-guided POBA (plain old balloon angioplasty) was performed. In case of a sufficient POBA result with residual stenosis < 40 %, FFR > 0.8 and no severe dissection, the target lesion was finally dilated using the DCB. Quantitative coronary angiography (QCA) was performed before and after the index procedure and at 6-month follow-up (f/u) to calculate late lumen loss (LLL) and net luminal gain (NLG). Optical coherence tomography (OCT) was performed at f/u to assess vascular remodeling. DCB-only treatment was applied to 43 patients (51 lesions), while 3 patients (3 lesions) needed provisional stenting. Invasive f/u was completed in 39 patients (47 lesions). At the stenotic site, the lumen diameter showed a trend toward progressive increase at f/u (LLL: −0.13 ± 0.44 mm, n.s.; NLG: 1.10 ± 0.53 mm, p < 0.001) without aneurysm formation or restenosis after DCB-only treatment.ConclusionsFFR-guided DCB-only PCI of de novo lesions appeared feasible and safe in stable CAD with clopidogrel discontinuation after 4 weeks, showing a trend toward positive vessel remodeling without lumen loss at 6 months.Clinical trial registration http://www.clinicaltrials.gov. Unique identifier: NCT02120859

Efficacy of Ultrasound-Guided Axillary Brachial Plexus Block for Analgesia During Percutaneous Transluminal Angioplasty for Dialysis Access.

To evaluate the efficacy and safety of ultrasound (US)-guided axillary brachial plexus block (ABPB) for analgesia during percutaneous transluminal angioplasty (PTA) for dialysis access. Twenty-one patients who underwent PTA for stenotic dialysis access shunts and who had previous experience of PTA without sedation, analgesia, and anesthesia were included. The access type in all patients was native arteriovenous fistulae in the forearm. Two radiologists performed US-guided ABPB for the radial and musculocutaneous nerves before PTA. The patients' pain scores were evaluated using a visual analog scale (VAS) after PTA, and these were compared with previous sessions without US-guided ABPB. The patient's motor/sensory paralysis after PTA was also examined. The mean time required to achieve US-guided ABPB was 8min. The success rate of this procedure was 100%, and there were no significant complications. All 21 patients reported lower VAS with US-guided ABPB as compared to without the block (p<0.01). All patients expressed the desire for an ABPB for future PTA sessions, if required. Transient motor paralysis occurred in 8 patients, but resolved in all after 60min. US-guided ABPB is feasible and effective for analgesia in patients undergoing PTA for stenotic dialysis access sites. Level 4 (case series).

Local blood pressure associates with the degree of luminal stenosis in patients with atherosclerotic disease in the middle cerebral artery.

The mechanism underlying atherosclerotic ischemic events within the middle cerebral artery (MCA) is unclear. High structural stress induced by blood pressure might be a potential aetiology as plaque rupture occurs when such mechanical loading exceeds its material strength. To perform reliable analyses quantifying the mechanical loading within a plaque, the local blood pressure is needed. However, data on MCA blood pressure is currently lacking. In this study, the arterial pressure proximal to the stenotic site in the MCA was measured in 15 patients scheduled for intervention. The relationships between these local measurements and pre-intervention and intra-intervention non-invasive arm measurements were assessed. The impact of luminal stenosis on the local blood pressure was quantified. Compared with the pre-intervention arm measurement, the intra-intervention arm pressure decreased significantly by 23.9 ± 11.8 and 9.3 ± 14.7 % at diastole and systole, respectively. The pressure proximal to the stenosis was much lower than the pre-intervention arm measurement (diastole: 65.3 ± 15.7 vs 82.0 ± 9.7, p < 0.01; systole: 81.1 ± 15.9 vs 133.9 ± 18.7, p < 0.01; unit: mmHg). The systolic pressure in the MCA in patients with stenosis <70 % (n = 6) was significantly higher than the value in patients with stenosis ≥70 % (n = 9) (92.0 ± 7.3 vs 73.9 ± 16.1, p = 0.02; unit: mmHg), as was pulse pressure (22.8 ± 6.4 vs 11.1 ± 8.3, p = 0.01; unit: mmHg). However, diastolic pressure remained unaffected (69.2 ± 9.3 vs 62.8 ± 19.0, p = 0.58; unit: mmHg). In conclusion, the obtained results are helpful in understanding the local hemodynamic environment modulated by the presence of atherosclerosis. The local pressure measurements can be used for computational analysis to quantify the critical mechanical condition within an MCA lesion.

Outcomes of Temporary Partially Covered Stent Placement for Benign Tracheobronchial Stenosis.

To evaluate the intermediate outcomes of temporary partially covered tracheobronchial stenting in patients with benign tracheobronchial stenosis. We conducted a retrospective study of patients with benign tracheobronchial stenosis who underwent stent placement. All stents were removed approximately 3months after placement. Respiratory function was assessed using the visual analogue scale (VAS) and Karnofsky performance status scale (KPS) before and after stent placement. The lumen diameters of the stenotic lesions were measured using chest computed tomography (CT) and compared between before stent placement and after stent removal. A total of 51 stents were successfully placed in consecutive 51 patients with benign tracheobronchial stenosis. No serious complications occurred. The mean VAS and KPS scores significantly improved after stent removal (6.291±0.495 and 25.352±10.533, respectively) compared with those before stent placement (1.493±0.504 and 60.140±16.344, respectively; P<0.05). The mean lumen transverse diameters of the stenotic site in trachea and main bronchus after stent removal (17.235±3.457 and 8.993±0.961mm; 1month post-removal; 16.353±4.132 and 8.357±1.082mm; 6months post-removal) were significantly larger than those before stent placement (7.876±2.351 and 2.143±0.770mm, respectively; P<0.05). However, the mean lumen diameters between 1 and 6months after stent removal had no significant difference (P>0.05). Temporary partially covered stenting may be a safe and effective treatment for benign tracheobronchial stenosis.

Restricted Pax3 Deletion within the Neural Tube Results in Congenital Hydrocephalus.

Congenital hydrocephalus is a common birth-defect whose developmental origins are poorly understood. Pax3-null mutants show defects in myogenesis, neural tube closure, neural crest morphogenesis, and heart development that, consequently, results in embryonic lethality. Here we demonstrate that conditional deletion of the mouse Pax3 transcription factor results in fully-penetrant congenital obstructive hydrocephalus. To identify the role of Pax3 during cranial development, we deleted Pax3 within the neuroepithelium (via Pax7−Cre), in the neural crest (via P0-Cre), and in both the neuroepithelium and the neural crest (via Wnt1-Cre). Only conditional mutants generated using Pax7−Cre or Wnt1-Cre developed early onset congenital hydrocephalus due to stenosis of the third ventricle, suggesting that loss of neuroepithelial Pax3 is sufficient to disturb third ventricle morphogenesis. Dilation of lateral ventricles occurs as early as E14.5, and lineage-mapping revealed that the neuroepithelial cells in the conditional mutants are present, but fail to undergo normal differentiation at the stenotic site. Concomitant with a narrowing of the mutant third ventricle, we detected ectopic apoptosis, reduced proliferation, and abnormal β-catenin localization. Furthermore, consistent with the overlapping expression pattern of Pax3 and Pax7 in early cranial neuroepithelium, we demonstrated a combinatorial role, as compound Pax3/Pax7 heterozygotes display partially-penetrant congenital hydrocephalus. These murine data provide an experimental paradigm underpinning clinical observations of the presence of PAX3 mutations in some hydrocephalic patients.

Establishment of a novel rat model of different degrees of portal vein stenosis following 70% partial hepatectomy.

Liver transplantation may fail due to complications of insufficient portal vein (PV) flow such as portal vein stenosis (PVS). Therefore, establishing a model to explore the effect of PV flow on liver regeneration is crucial and essential. Rats were randomly divided into 6 groups: sham operation rats group; 70% partial hepatectomy (PH) group (group A); PVS groups with mild, moderate, or severe stenosis (group B–D) and portal vein ligation (PVL) group. PVS was produced by ligating PV with parallelly placed needles of different gauges. Ultrasound was performed to validate the stenosis ratio (SR) and velocity ratio (VR) at the prestenotic and stenotic site. Rats were sacrificed on day 1,3,7, and 14 after surgery, and liver regeneration rate (LRR) was calculated. We successfully established rat models of different degrees of PVS following 70%PH in 72 rats. The SRs of each PVS group were 44.8 ± 5.23%, 59.3 ± 4.07% and 69.5 ± 2.17%, which showed no statistical differences compared with those measured by stenosis ratio measured by ultrasound. The survival rate in groups A-D were 100%, 83.3%, 66.7% and 50% respectively. Differences were demonstrated between groups A and C, as well as groups A and D (both P<0.05). Moreover, LRR negatively correlated with SRu and VR, and the correlation coefficients were −0.534 and −0.522, respectively. The rat model we established has the potential to be applied in most conditions of liver regeneration with reduced PV inflow, and it provides a foundation for further exploring the relationship between PV hemodynamic changes and liver regeneration.

Fluid-Structure Interaction Analysis for Drug Transport in a Curved Stenotic Right Coronary Artery

A blockage of blood vessels resulting from thrombus or plaque deposit causes serious cardiovascular diseases. This study developed a computational model of blood flow and drug transport to investigate the effectiveness of drug delivery to the stenotic sites. A three-dimensional (3D) model of the curved stenotic right coronary artery (RCA) was reconstructed based on the clinical angiogram image. Then, blood flow and drug transport with the flexible RCA wall were simulated using the fluid structure interaction (FSI) analysis and compared with the rigid RCA wall. Results showed that the maximal total displacement and von Mises stress of the flexible RCA model are 2.14 mm and 92.06 kPa. In addition, the effective injecting time point for the best performance of drug delivery was found to be between 0 s and 0.15 s (i.e., the fluid acceleration region) for both rigid and flexible RCA models. However, there was no notable difference in the ratio of particle deposition to the stenotic areas between the rigid and flexible RCA models. This study will be significantly useful to the design of a drug delivery system for the treatment of the stenotic arteries by targeting drugs selectively to the stenotic sites.

Resection And Reconstructive-plastic Surgery In Treatment Of Extended And Multifocal Cicatrical Tracheal Stenosis

Background. Main issues of treatment of patients with cicatricial stenosis of trachea (CST) are to increase its efficacy and safety, as well as to determine indications and contraindications for circular resection and reconstructive interventions on the trachea in patients with extended lesions of trachea, with stenoses involving subvocal cords part of larynx and well as multifocal narrowing of the trachea which could improve treatment results and quality of life of patients, to gain recovery and reduce disability and mortality.Material and methods. One hundred two patients aged from 11 to 62 years with CST were surgically treated. Stenotic site length in patients varied from 0,3 to 7 cm. Most frequently (64,2%), CST length of more than 2 cm was observed. In critical and decompensated stenosis with diameter of CST up to 5 mm with the threat of asphyxiation by the first stage we used endoscopic laser-and electric destruction of constriction followed by restricted zone bouging. If long-term rehabilitation was necessary and in case of absence of the conditions to the implementation of circular tracheal resection, we used tracheal stents. Circular resection of the trachea was performed in 24 patients. In case of contraindications, 28 patients underwent reconstructive plastic surgery with dissection the stenosis, excision of scar tissue and formation of trachea lumen in T-tube. After removing T-tube plasty of anterior tracheal wall and of soft tissues of the neck defects was performed using local tissues and grafts with microsurgical techniques.Results. Long-term results of treatment evaluated and studied in a period of 6 months to 5 years in 89 (87.3%) patients. 13 patients continues to one of the stages of complex treatment. Еhe patients are under dynamic endoscopic control. Good results were achieved in the treatment of 71 patients (79.8%), satisfactory - in 12 (13.4%), unsatisfactory results in 6 (6.7%) patients.Conclusions. 1. Patients with CST should undergo multimodal approach depending on degree and localization of narrowing, length and levels of restriction, taking into account severity of associated pathologies using complex of endosurgical, resection and reconstructive treatments. 2. When an extended CST involvement in the process is more than 30–50% of the trachea up to 5-6 cm, it’s possibly to perform circular tracheal resection provided that mobilization of necessary levels is sufficient. 3. In case of multifocal CST in conjunction with subglottic stenosis of the larynx formation of the lumen, it is expedient to form a lumen in the T-tube.

Subject-Specific Fully-Coupled and One-Way Fluid-Structure Interaction Models for Modeling of Carotid Atherosclerotic Plaques in Humans.

BackgroundHemodynamics play an important role in the development and progression of carotid atherosclerosis, and may be important in the assessment of plaque vulnerability. The aim of this study was to develop a system to assess the hemodynamics of carotid atherosclerotic plaques using subject-specific fluid-structure interaction (FSI) models based on magnetic resonance imaging (MRI).Material/MethodsModels of carotid bifurcations (n=86 with plaques from 52 patients, n=14 normal carotids from 12 participants) were obtained at the Department of Radiology, Beijing Tian Tan Hospital between 2010 and 2013. The maximum von Mises stress, minimum pressure, and flow velocity values were assessed at the most stenotic site in patients, or at the carotid bifurcations in healthy volunteers. Results of one-way FSI were compared with fully-coupled FSI for the plaques of 19 randomly selected models.ResultsThe maximum von Mises stress and the minimum pressure and velocity were significantly increased in the stenosis group compared with controls based on one-way FSI (all P<0.05). The maximum von Mises stress and the minimum pressure were significantly higher and the velocity was significantly lower based on fully coupled FSI compared with on-way FSI (all P<0.05). Although there were differences in numerical values, both methods were equivalent. The maximum von Mises stress of vulnerable plaques was significantly higher than stable plaques (P<0.001). The maximum von Mises stress of the group with fibrous cap defect was significantly higher than the group without fibrous cap defect (P=0.001).ConclusionsThe hemodynamics of atherosclerotic plaques can be assessed noninvasively using subject-specific models of FSI based on MRI.

Optical coherence tomography-based predictors for creatine kinase-myocardial band elevation after elective percutaneous coronary intervention for in-stent restenosis.

We evaluated whether morphological characteristics of neointimal tissue of in-stent restenosis (ISR) lesions assessed by optical coherence tomography (OCT) affect periprocedural elevation of creatine kinase-myocardial band (CK-MB). The impact of neointimal characteristics of ISR lesions on periprocedural myocardial injury has not been sufficiently investigated. A total of 125 patients with ISR lesions underwent elective percutaneous coronary intervention (PCI) and pre-PCI OCT examination. Measurements of CK-MB were performed upon hospitalization, before PCI, and every 8 hr for 24 hr after PCI. CK-MB elevation was defined as levels above the 99th percentile of the upper reference limit. Neoatherosclerosis was defined as neointima with lipid or calcification. Post-PCI CK-MB elevation was observed in 20 (16.0%) patients. The maximum length of consecutive cross-sections with neoatherosclerosis on the longitudinal axis of the stent was significantly larger in patients with post-PCI CK-MB elevation than in those without [8.8 mm (1.5-10.4) vs. 0.0 mm (0.0-1.0), P < 0.001], and thin-cap fibroatheroma (TCFA) were more frequently observed at the site of minimal lumen cross-sectional area in patients with post-PCI CK-MB elevation (55.0% vs. 1.9%, P < 0.001). Multivariate analysis revealed that the maximum length of segments with neoatherosclerosis [odds ratio (OR), 1.463; 95% confidence interval (CI), 1.090-1.962; P = 0.011] and TCFA (OR, 14.328; 95% CI, 1.118-183.628; P = 0.041) were independent predictors for post-PCI CK-MB elevation. A greater axial length of neoatherosclerosis and the presence of TCFA at the most stenotic site were significantly associated with post-PCI CK-MB elevation in ISR lesions.

Congenital oesophageal stricture in an Arabian filly treated by balloon dilation

SummaryCongenital oesophageal stricture was diagnosed via endoscopy in a 3‐day‐old Arabian filly suffering from nasal milk regurgitation. Vascular ring anomaly or other extramural, intramural or intraluminal causes were not identified on radiographs or on a computed tomography scan; thus a functional abnormality was suspected. The filly was treated with antibiotics for aspiration pneumonia and was fed milk through an indwelling nasoesophageal tube. Two sessions of balloon bougienage at the stenotic site, under sedation, resulted in marked clinical improvement and thereafter the filly was gradually reintroduced to suckling from the mare. The filly was discharged from the hospital after 17 days and on follow‐up there were no reports of food regurgitation even after the introduction of solid food. The filly was still doing well in the latest follow‐up at age 11 months.

Magnetic resonance imaging features of Great Danes with and without clinical signs of cervical spondylomyelopathy.

To characterize and compare the MRI morphological features of the cervical vertebral column of Great Danes with and without clinical signs of cervical spondylomyelopathy (CSM). Prospective cohort study. 30 Great Danes (15 clinically normal and 15 CSM-affected). All dogs underwent MRI of the cervical vertebral column (C2-3 through T1-2). Features evaluated included sites of subarachnoid space compression, spinal cord compression, or both; degree, cause, and direction of compression; MRI signal changes of the spinal cord; articular process (facet) joint characteristics; internal vertebral venous plexus visibility; and presence of extradural synovial cysts as well as presence and degree of intervertebral disk degeneration and foraminal stenosis. Clinically normal and CSM-affected dogs had 11 and 61 compressive sites, respectively, detected with MRI. All CSM-affected dogs had ≥ 1 site of spinal cord compression. No signal changes were observed in spinal cords of normal dogs, whereas 14 sites of hyperintensity were found in 9 CSM-affected dogs. Foraminal stenosis was present in 11 clinically normal and all CSM-affected dogs. The number of stenotic foraminal sites was significantly greater in the CSM-affected group, and severe stenosis appeared to be more common in this group than in the clinically normal group. Significant differences were identified between clinically normal and CSM-affected dogs with regard to amount of synovial fluid evident, regularity of articular surfaces, degree of articular process joint proliferation, and internal vertebral venous plexus visibility. Abnormalities were detected with MRI in several clinically normal Great Danes. Severe spinal cord compression, number of stenotic foraminal sites, and signal changes within the spinal cord distinguished CSM-affected from clinically normal Great Danes.