Stenotic Site Research Articles

Ultrasonographic hemodynamics for prediction of poor liver regeneration induced by severe portal vein stenosis in rats.

BackgroundInsufficient portal vein blood flow, such as portal vein stenosis (PVS), plays a significant influence on liver regeneration. Early prediction of poor liver regeneration induced by severe PVS is critical. Ultrasound serves as a first-line imaging technique in diagnosing PVS based on the changes of portal vein hemodynamics. However, there is still no consensus on the criteria for evaluating the degree of PVS. Moreover, which degree of PVS can induce poor liver regeneration still is unclear. Therefore, it is essential to determine the stenosis degree that leads to significantly poor liver regeneration and to evaluate the value of ultrasonographic hemodynamics for predicting poor liver regeneration induced by severe PVS.MethodsRats were randomly subjected to sham operation rats group (SOR), PH group (group A), and PVS groups with mild, moderate, or severe stenosis flowing PH (groups B-D). PH group was set up a model of 70% hepatectomy, and PVS groups were produced by different degrees of partial portal vein ligation following PH. In the SOR group and PH group, the portal vein diameter (PVD) and portal vein velocity (PVV) were measured by Ultrasound at preoperative and postoperative 1, 3, 7, and 14 d. In PVS groups, PVD and PVV at the stenotic (PVDs, PVVs) and pre-stenotic (PVDpre, PVVpre) sites were also detected on 1, 3, 7, and 14 d after surgery, calculating the diameter stenosis ratio (DSR) and accelerating blood flow velocity ratio (AVR). Rats were sacrificed at 1, 3, 7, and 14 d post-surgery, and the expression of proliferating cell nuclear antigen (PCNA) and the liver regeneration rate (LRR) at 14 d were evaluated. The PVVs, DSR, and AVR in the different groups were analyzed combined with the status of liver regeneration, and receiver operating characteristic (ROC) analysis was also applied to assess the value of PVVs, DSR, and AVR in diagnosing severe PVS and the resulting poor liver regeneration.ResultsSeventy-two rat models of different degrees of PVS were successfully set up following 70% PH. The stenosis ratios (SRs) of each PVS group were 45.16%±3.44%, 59.21%±3.83%, and 69.56%±2.16%, respectively. Poor liver regeneration appeared to be significant when PVS was greater than 65% (group D), of which the LRR at 14 d was significantly lower compared to PH group (group A) and PVS groups with SR ≤50% (group B) and SR >50–65% (group C), respectively (all P<0.05). Meanwhile, PCNA expression of group D was significantly lower compared to group C at 1 d and groups A-C at 3 d (all P<0.05). Differences were also detected at 3 d between groups A and B and groups A and C (both P<0.05). Among PVS groups, PVVs accelerated dramatically, with significant differences demonstrated between group D and groups B and C at 1 d, as well as group B and groups C and D at 3 d (all P<0.05). At 1, 3, and 7 d, DSR of groups C and D were significantly higher than that of group A (all P<0.05). At 1 and 3 d, AVR of group D was significantly higher than that of groups B and C (all P<0.05). ROC analysis showed the AUC of PVVs at 1 d in diagnosing severe PVS was 0.84, while at 3 d, it was unable to differentiate from mild-moderate or severe PVS by PVVs (P>0.05 vs. AUC =0.50). At 1 and 3 d, the AUC of DSR and AVR in diagnosing severe PVS were all greater than 0.80, comparatively much better in AVR (AUC >0.95). The best cut-off points of AVR at 1 and 3 d were 6.91 and 5.36, with the sensitivity and specificity respectively 100%, 91.67% at 1 d, and 100%, 83.33% at 3 d.ConclusionsPoor liver regeneration could be significantly induced when PVS was greater than 65%. Ultrasound can well prove the changes of portal vein hemodynamics in different degrees of PVS in rats. The parameters PVVs could be regarded as a valid index for diagnosing PVS but were not applicable for evaluating the stenosis degree. Comparatively, the parameters DSR and AVR, especially AVR, proved to be useful for differentiating severe PVS (>65%) in the early postoperative period, predicting the resulting poor liver regeneration.

Application value of preoperative high-resolution magnetic resonance vessel wall imaging evaluation on symptomatic middle cerebral artery stenosis stenting

Objective To investigate the value of preoperative high-resolution magnetic resonance vessel wall imaging (HRMR-VWI) in stenosis stenting for symptomatic middle cerebral artery. Methods The clinical data of 35 patients with atherosclerotic stenosis in middle cerebral artery (MCA) M1 segment who were treated with stenting therapy (stenting angioplasty) at Department of Neurosurgery, Tianjin Huanhu Hospital from August 2011 to May 2019 were analyzed retrospectively. HRMR-VWI results were used to evaluate the location, composition and stability of plaques before operation. The mortality and morbidity at 30 days post operation were determined by clinical follow-up. The ischemic stroke and restenosis rates at 12 months post operation were confirmed by imaging follow-up. Results The preoperative HRMR-VWI of 35 patients showed that the plaques in 15 cases were located on the ventral vessel wall, those in 12 on the inferior, and those in 8 on the upper vessel wall. Seven patients had unstable plaques in the M1 segment of MCA. The stents were successfully placed in 35 patients and well adhered with smooth blood flow. Technical complications occurred in 2 (5.7%) patients. One patient (2.8%) died of cerebral hernia due to reperfusion hemorrhage in 30 days after surgery, although decompressive craniectomy and hematoma clearing were performed. One patient (2.8%) had residual neurological dysfunction. Twelve months after the operation, no ischemic stroke occurred in 34 patients, and no restenosis occurred in the 5 patients who were followed up by imaging. Conclusion HRMR-VWI has a high diagnostic value for the location and stability of plaques in stenotic sites of MCA, which could improve the safety and effectiveness of stenting of MCA M1 segment stenosis. Key words: Middle cerebral artery; Endovascular procedures; Stents; Atherosclerotic stenosis; High resolution magnetic resonance vessel wall imaging

A coupled one dimension and transmission line model for arterial flow simulation.

A broad choice of numerical schemes and methods currently exists for blood flow simulations. The results rely critically on the prescription of boundary conditions. The outflow boundary condition for a one-dimensional (1D) flow solver is usually prescribed via a Windkessel or lumped parameter model. The weakness of such an approach is the determination of the parameters. In the present work, we use an alternative approach, that is, a reflection coefficient (RC), to lumped parameter models for distal boundary conditions. With such a RC, the number of parameters required is reduced to one. We derive the theoretical foundation for the RC. Specifically, we couple a transmission line theory for peripheral resistance with a 1D arterial flow solver. We apply this method to a healthy and a stenosed virtual aorta, and show this method can reproduce some subtle features in arterial pressure propagation, such as the steepened pressure waveform and the reflection from the stenosed site. In summary, the RC parameter has strong physical implications in the theory of wave propagation and may be used in flow simulations where reflections need to be explicitly modeled. NOVELTY STATEMENT: A novel coupled one-dimensional-transimission line model has been developed in this work with detailed implementations. Only one outflow boundary condition, that is, the refection coefficient is required in the model. Reflections for a pulse wave from aortic terminals as well as from a stenotic site are numerically simulated.

Abstract TP126: Evaluation of Pre-Stenotic Hemodynamic Differences in Unilateral Carotid Stenosis After Artificial Carotid Plaque Removal

Introduction: There is still insufficient to determine which carotid stenosis is likely to progress. The carotid artery shape is an independent risk factor for intimal thickening. Although it is assumed that hemodynamic factors are strongly involved in the mechanisms, the details are unknown. Here, we removed carotid plaques in unilateral carotid stenotic cases, and reproduced the vessel shape without plaques as after carotid endarterectomy, and compared hemodynamic distributions with the non-stenotic side. Methods: We used 30 cases of unilateral carotid stenosis (area stenosis rate &gt; 60%) registered in the National Hospital Organization Prospective Clinical Study; Carotid CFD Study. The plaques in DICOM images were artificially removed (Figure 1), and the vessel shape without plaque was reproduced. Patient-specific arterial geometries and inflow velocities were obtained from 3D-CTA and carotid doppler examinations.We compared distributions of hemodynamic indices (time-averaged wall shear stress (WSS), time-averaged WSS gradient, normalized WSS, normalized WSS gradient, OSI and NtransWSS) at 3 regions; the stenotic site, its proximal and distal sites (10 mm). Results and Conclusions: The average age was 71.6 years, male 23 cases, hypertension 20, diabetes 7, dyslipidemia 15, smoking history 22, and average area stenosis rate 72.6%. Normalized WSS was lower (p&lt;0.0001, Wilcoxon signed rank test), and NtransWSS (p=0.0242) and OSI (p=0.0355) were higher in the stenotic sites of vessels after plaque removal (Figure 2). The data suggest that low and disturbed WSS caused by differences in carotid shape may contribute to the progress in stenosis at the carotid bifurcation.

Carotid Artery Plaque Echomorphology and its Association with Histopathological Characteristics May Predict Symptomatic Disease

Introduction - A number of ultrasonic texture features which include severity of stenosis, grey scale median (GSM), plaque area (PA), juxtaluminal plaque area (JBA) and discrete white area (DWA) have been shown to be independent predictors of future strokes in carotid disease patients. The primary aim of the present study was to determine the association between histological features and ultrasonic plaque texture features after carotid endarterectomy. Secondary aim was to assess the association between statin therapy and symptomatic disease or other histological features. Methods - B-mode ultrasound images of carotid plaques were obtained during preoperative scanning and texture measurements were made using commercially available software (LifeQ Medical). Histological transverse plaque sections of the most severe stenotic site were graded 0-3 for the number of macrophages (CD68 staining), severity of angiogenesis (CD31 staining), smooth muscle cell numbers (SMC) and size of lipid core; and 0 or 1 for thickness of fibrous cap, presence of intraplaque haemorrhage (IPH), plaque rupture and instability. Demographics, co-morbidities, statin therapy and total cholesterol level were also recorded. Multivariable logistic regression models of symptoms as the dependent variable and of histological features (model a) and ultrasonic features (model b) as the independent variables were undertaken. Results - B-mode ultrasound images (mean stenosis of 86%; range 60-99%) from 70 consecutive patients (20 symptomatic and 50 asymptomatic) were obtained. The presence of CD 68 was correlated with lower values of GSM (p=0.001) and presence of DWA (p=0.001). Increased number of SMCs was associated with higher values of GSM (p=0.003), lower DWA (p=0.003) and JBA (p=0.042) and lower degree of stenosis (p=0.025). Presence of CD 31 was associated with lower values of GSM (p=0.003) and presence of DWA (p<0.001). Larger lipid core and unstable plaques were associated with lower values of GSM (p=0.001; p=0.002 respectively), presence of DWA (p=0.025; p=0.027 respectively) and JBA (0.0013; p=0.006 respectively). Statin therapy after being adjusted for symptoms, was associated with lower percentage of CD 68 (OR: 0.17; 95% confidence interval [CI]: 0.04 to 0.73; P=0.038), lower degree of CD 31 (OR: 0.17; CI 0.04 to 0.75, p= 0.019) and higher percentage of SMCs (OR: 6.02; CI: 1.28 to 28.1, p= 0.023). In model (a) the presence of CD68, SMCs and intraplaque hemorrhage were independent predictors of symptomatic plaques. [ROC Area under the curve: 0.870; 95% CI 0.767 to 0.973. (85.7 % correct classification of plaques into symptomatic or asymptomatic for a cut value of 0.50 probability)]. In model (b) the presence of DWA and JBA were independent predictors of symptomatic plaques [ ROC Area under the curve: 0.701; 95% CI 0.562 to 0.840. (76.7 % correct classification of plaques into symptomatic or asymptomatic for a cut value of 0.50 probability)]. Conclusion - The presence of markers indicative of inflammation and neo-angiogenesis as histopathologic plaque characteristics are associated with unstable carotid atheroma based on ultrasonic analysis. Histological features such as CD68, SMCs and intraplaque hemorrhage and ultrasonic features such as DWA and JBAmay be predictors of symptomatic plaques.

Stent implantation for severe pulmonary vein stenosis or occlusion secondary to atrial fibrillation ablation

BackgroundCatheter interventional treatment of pulmonary vein stenosis or occlusion (PVS/O) following radiofrequency ablation (RFA) for atrial fibrillation (AF) remains a challenging field due to lacking randomized data and there are limited data about stenting. MethodsAll patients at our center who underwent pulmonary vein stenosis (PVS) stenting for PVS/O induced by RFA were retrospectively assessed. Clinical presentation, anatomic site of stenosis and hemodynamic information, as well as follow-up data, were collected and analyzed. ResultsFrom January 2010 to June 2018, 56 patients with PVS/O secondary to RFA were treated with 113 stents. Procedural success rate was 95.8%. Pressure gradients significantly reduced (p < 0.001) and vessel caliber markedly increased (p < 0.001) in all the stenotic sites, with immediate symptoms significantly improved. The overall in-stent restenosis (ISR) rate was 21.8% after a median follow-up period of 26 months (interquartile range: 16 to 35.5 months). The incidence of ISR was higher in patients treated with stent diameter ≤ 8 mm than those with stent diameter >8 mm (HR: 3.91; 95% CI 1.74–8.81; p = 0.001). ConclusionsPVS stenting is a safe and effective procedure for PVS/O secondary to RFA. Long-term patency and good clinical outcomes are gained after bigger-diameter stent implantation.

P5615A randomised study comparing FFR-guided paclitaxel-coated balloon angioplasty vs. drug-eluting bioresorbable scaffolds with 9 months invasive follow-up

Abstract Background Elimination of a permanent metallic stent from standard PCI techniques is desirable since mid- and longterm adverse reactions are attributed to an intracoronary foreign body. Purpose To investigate two “metal-free” PCI techniques using either drug-coated balloons (DCB) or bioresorbable scaffolds (BRS) in stable coronary artery disease regarding their safety and efficacy (NCT02607241) and clinical course. Methods 59 patients (table 1) were prospectively randomized for elective PCI of de novo stenosis with either BRS implantation (N=28) or with DCB only angioplasty (N=31). The DCB only arm was treated by a previously implemented protocol including sequential balloon predilations and repetitive FFR (fractional flow reserve) measurements. Stenting was deferred if FFR was &gt;0.80 and in the absence of flow-limiting dissections after final DCB dilatation. All BRS were post-dilated using a non-compliant balloon. All BVS were post-dilated (non-compliant balloon). Optical coherence tomography (OCT) was performed during index procedure and at 9-month f/u. Results Both groups were well balanced without significant differences in clinical characteristics (table 1). Procedural success was achieved in 89.3% in the BRS and 77.4% in the DCB group. Parameter of quantitative coronary angiography are shown in the table 2. The predefined primary end point (efficacy) net luminal gain was significantly larger in the DCB group (noninferiority t-Test, margin: 0.2mm, 80% power). Accordingly, the secondary endpoint late lumen loss indicated with −0.20±0.73 vessel enlargement at the stenotic site in the DCB group at 9-month f/u. Target lesion failure during 9-month f/u occurred much more in the BRS group (14.3% (N=4) vs. 3.2% (N=1), p=0.180) but did not reach significance in this small sample size. In detail, there were 2 scaffold thrombosis despite OCT-guided index procedure in the BRS group with subsequent myocardial infarction, and 2 restenosis in the BRS vs. 1 restenosis in the DCB group requiring repeat target lesion revascularization. Due to safety concerns of BRS and the worldwide recall of Absorb BRS the study was prematurely terminated. Conclusion Our data add evidence for FFR-guided “DCB only” PCI as an attractive, safe and feasible alternative by showing a favorable longterm course contrary to the late lumen loss of conventional coronary stents. The Absorb BRS is potentially harmful with a high percentage of target lesion failure including scaffold thrombosis despite OCT-guided implantation and should be avoided.

Fractional flow reserve-based 4D hemodynamic simulation of time-resolved blood flow in left anterior descending coronary artery

BackgroundThe purpose of this study was to investigate the feasibility of the non-invasive assessment of hemodynamic parameters with computational fluid dynamics in left anterior descending coronary artery based on invasive fractional flow reserve. MethodsA left coronary artery model based on computed tomography angiography was reconstructed using MIMICS 18.0 for computational fluid dynamics analysis. With actual fractional flow reserve measured from the patient, 4D hemodynamic profiles of time-resolved blood flow were simulated. FindingsThe 4D blood flow simulation could provide extensive information of blood flow status. Hemodynamic parameters, such as velocity, wall shear stress and pressure were simulated throughout the cardiac cycle. There might be high flow velocities and high wall shear stress in the stenotic region throughout the whole cycle, both of which peaked in the case of the maximum inlet differential pressure. The reverse flow and vortex were detectable at the downstream areas beneath the stenotic site. The pressure remarkably increased near the proximal stenotic end and declined in the mid-stenosis. Moreover, the simulation results provided detailed and accurate mass flow measurements of hemodynamic parameters as well. InterpretationThe computational fluid dynamics analysis of 4D blood flow based on fractional flow reserve is feasible in left anterior descending coronary artery. It presents the merits of providing both qualitative and quantitative information for further investigation of the links between hemodynamic parameters and left anterior descending artery stenosis.

Computational Fluid Dynamics-Based Blood Flow Assessment Facilitates Optimal Management of Portal Vein Stenosis After Liver Transplantation

BackgroundPortal vein stenosis develops in 3.4–14% of split liver transplantation1–3 and its early detection and treatment are essential to achieve long-term graft survival,2–5 although the diagnostic capability of conventional modalities such as Doppler ultrasound and computed tomography is limited.1,4,5 MethodsThis study used computational fluid dynamics to analyze portal vein hemodynamics in the management of post-transplant portal vein stenosis. To perform computational fluid dynamics analyses, three-dimensional portal vein model was created using computed tomographic DICOM data. The inlet flow condition was set according the flow velocity measured on Doppler ultrasonography. Finally, portal vein flow was simulated on a fluid analysis software (Software Cradle, Japan). ResultsAn 18-month-old girl underwent liver transplantation using a left lateral graft for biliary atresia. At the post-transplant 1-week evaluation, the computational fluid dynamics streamline analysis visualized vortices and an accelerated flow with a velocity ratio < 2 around the anastomotic site. The wall shear stress analysis revealed a high wall shear stress area within the post-anastomotic portal vein. At the post-transplant 6-month evaluation, the streamline analysis illustrated the increased vortices and worsening flow acceleration to reach the proposed diagnostic criteria (velocity ratio > 3:1).3,5 The pressure analysis revealed a positive pressure gradient of 3.8 mmHg across the stenotic site. Based on the findings, the patient underwent percutaneous transhepatic portal venoplasty with balloon dilation. The post-treatment analyses confirmed the improvement of a jet flow, vortices, a high wall shear stress, and a pressure gradient. DiscussionThe computational fluid dynamics analyses are useful for prediction, early detection, and follow-up of post-transplant portal vein stenosis and would be a promising technology in post-transplant management.

Prediction of Plaque Progression in Coronary Arteries Based on a Novel Hemodynamic Index Calculated From Virtual Stenosis Method.

RationalePredicting the sites in coronary arteries that are susceptible to plaque deposition is essential for the development of clinical treatment strategies and prevention. However, to date, no physiological biomarkers for this purpose have been developed. We hypothesized that the possibility of plaque deposition at a specific site in the coronary artery is associated with wall shear stress (WSS) and fractional flow reserve (FFR).Background and ObjectiveWe proposed a new biomarker called the stenosis susceptibility index (SSI) using the FFR and WSS derived using virtual stenosis method. To validate the clinical efficacy of this index, we applied the method to actual pilot clinical cases. This index non-invasively quantifies the vasodilation effects of vascular endothelial cells relative to FFR variation at a specific coronary artery site.Methods and ResultsUsing virtual stenosis method, we computed maximum WSS and FFR according to the variation in stenotic severity at each potential stenotic site and then plotted the variations of maximum WSS (y-axis) and FFR (x-axis). The slope of the graph indicated a site-specific SSI value. Then we determined the most susceptible sites for plaque deposition by comparing SSI values between the potential sites. Applying this method to seven patients revealed 71.4% in per-patient basis analysis 77.8% accuracy in per-vessel basis analysis in percutaneous coronary intervention (PCI) site prediction.ConclusionThe SSI index can be used as a predictive biomarker to identify plaque deposition sites. Patients with relatively smaller SSI values also had a higher tendency for myocardial infarction. In conclusion, sites susceptible to plaque deposition can be identified using the SSI index.

Quantitative score of the vessel morphology in middle cerebral artery atherosclerosis

BackgroundWe aimed to quantitatively assess the vessel morphology of middle cerebral artery (MCA) atherosclerosis and explore its value in discriminating plaque types. MethodsPatients were selected from a high-resolution magnetic resonance imaging (HRMRI) study from January 2007 to December 2015. One hundred and three patients with acute cerebral infarcts due to MCA stenosis (>50%) and eighty-nine patients with asymptomatic MCA stenosis (>50%) were included. Quantitative measurements of MCA morphology, including lumen area, outer-wall and wall area at stenotic site and reference site, stenotic degree, plaque length, remodeling index and plaque eccentricity, were performed on HRMRI with observers blinded to clinical presentations. Firth's penalized logistic regression analysis was used to construct a symptomatic plaque score (SPS) model. Then, the HRMRI data of 39 patients prospectively enrolled from January 2016 to January 2017 were used to validate the SPS model. ResultsThe HRMRI data of 103 patients with symptomatic MCA stenosis and 89 patients with asymptomatic MCA stenosis in the construction cohort were analyzed. Four main factors were found to be associated with symptomatic plaques: stenotic lumen area ≥ 2.28 mm2, stenotic wall area ≥ 8.88 mm2, plaque length and presence of an eccentric plaque. Summation of each logistic regression coefficient multiplying the corresponding score produced the SPS with an area under curve (AUC) of 0.890 on receiver operating characteristics analysis. Validation of the score of 39 plaques (19 symptomatic and 20 asymptomatic) revealed an AUC of 0.862, confirming the continued diagnostic ability. When the data were pooled in all 235 plaques, the optimal cutoff score of discriminating symptomatic and asymptomatic plaques was 2.79 (SPS ≥ 2.79 indicating a symptomatic plaque) with AUC = 0.886, sensitivity 81.1% and specificity 80.5%. ConclusionsThe quantitative analysis of MCA morphology can independently and accurately discriminate plaque types, suggesting its close association with the underlying pathophysiology. Further prospective studies are required to verify whether the SPS model is clinically valuable in monitoring plaque progression and assessing the vulnerability.

Dynamic Changes of Cauda Equina Motion Before and After Decompressive Laminectomy for Lumbar Spinal Stenosis With Redundant Nerve Roots: Cauda Equina Activation Sign

Study Design:Cross-sectional observational study (consecutive case series).Objectives:The aim of this study was to define a criterion for achieving successful decompression of lumbar spinal stenosis (LSS) using intraoperative ultrasonography (IOUS) and to investigate the pathogenesis of redundant nerve roots (RNRs) based on the ultrasonographic findings.Methods:A total of 100 LSS patients (71 males, 29 females, mean age, 71 ± 8 years) with RNRs were enrolled as subjects in this study. IOUS was performed to evaluate pulsatile motion of the cauda equina (PMCE) just before and after decompressive laminectomy. To determine the decompression status of the cauda equina, the ultrasonographic findings were classified into 3 types on the basis of the presence or absence of PMCE: type 1, predecompression PMCE (−) to postdecompression PMCE (+); type 2, pre- and postdecompression PMCE (+); and type 3, pre- and postdecompression PMCE (−). The pathogenesis of RNRs was also investigated based on the ultrasonographic findings.Results:Around the stenosis, PMCE was almost always absent before decompression and appeared after decompression (type 1 in 94 patients, type 2 in 6, type 3 in 0). IOUS showed that, before decompression, the cauda equina was held at the stenosis and could not pulsate beyond the stenotic site, and after decompression, PMCE recovered in the craniocaudal direction, leading to the resolution of RNRs.Conclusions:The emergence of PMCE can be a sign of successful decompression for LSS. Ultrasonographic findings support the notion that disturbance of PMCE around the stenosis is a basic component of the pathogenesis of RNRs.

A Rare Case of Symptomatic Carotid Stenosis Caused by Mechanical Stimulation by Thyroid Cartilage and Frequent Swimming

Background: Bony structures around the carotid artery such as the styloid process and hyoid bone can cause dissection, compression, plaque formation, and plaque rupture of the carotid artery. To the best of our knowledge, this case is the first finding of thyroid cartilage being the cause of a lesion corresponding to adjacent common carotid artery (CCA) atherosclerosis. Case Description: A 51-year-old man with a history of hypertension and dyslipidemia suddenly experienced right facial numbness and dysphasia while front crawl swimming, which he usually did 3 times weekly. Diffusion-weighted magnetic resonance imaging showed high intensity areas in the left frontal and parietal lobes. He was diagnosed with acute cerebral infarction and was administered with tissue plasminogen activator. Angiography of the left CCA revealed mild stenosis with an intravascular filling defect, and carotid duplex ultrasonography of the CCA on the second day after symptom onset showed plaque and intraluminal thrombus at the stenotic site. Plain and contrast-enhanced computed tomography showed that thyroid cartilage contacted the left CCA at the stenotic site, and the left CCA moved backward and forward with the thyroid cartilage during neck rotation. We determined that mechanical stimulation by the thyroid cartilage had induced the plaque during the frequent neck rotation that is a feature of front crawl swimming. Conclusions: Evaluation of anatomical interactions between the carotid artery and bony structures including the thyroid cartilage is important to ensure that appropriate treatment is selected to prevent further ischemia.

Transjugular percutaneous endovascular treatment of dysfunctional hemodialysis access.

To evaluate the feasibility and the outcomes of transjugular percutaneous endovascular treatment of dysfunctional hemodialysis access in patients with chronic kidney disease. A total of 50 transjugular treatments in 38 patients with arteriovenous fistulas or arteriovenous grafts from September 2011 to May 2015 were included in this study. Medical records and angiographies were retrospectively reviewed. Success rate, patency rate, procedure time, and complications including internal jugular vein stenosis were evaluated. A total of 50 sessions of transjugular treatments were performed in 38 patients. There were 31 native arteriovenous fistulas including 10 immature cases and 19 arteriovenous grafts. Among the 50 cases, technical success was achieved in 45 and clinical success was achieved in 44; 37 cases (74%) with multiple stenotic sites were treated by the transjugular approach without placement of cross-sheaths. The mean time from puncture of the internal jugular vein to first fistulography was 10 min, and the mean total procedure time was 64 min. The primary patency rate at 6 months was 77%, while the secondary patency rate at 6 months was 97%. Perforation occurred in two cases during conventional percutaneous transluminal angioplasty after failure of the transjugular approach. One dissection occurred during the transjugular approach. There was no newly developed internal jugular vein stenosis during a mean follow-up period of 19.3 months. For the treatment of dysfunctional or immature hemodialysis access, the transjugular approach is a feasible and effective option that avoids injury to the graft or draining vein, especially in immature fistulas.

Optimization of balloon coating process for paclitaxel coated balloons via micro-pipetting method

Drug coated balloons (DCBs) have proven to be a suitable alternative for the treatment of cardiovascular diseases. They allow for uniform delivery of an antiproliferative drug to the stenotic site without permanent implantation of the device in the patient’s body. There are, however, regulatory concerns regarding the lack of data associated with variable drug delivery to the target site, which can be related to the coating process. This study describes the process for an in-house micro-pipetting coating method that incorporates a laboratory-developed coating equation for determining optimal coating parameters. The coating solutions included a common drug of choice, paclitaxel, along with a hydrophilic excipient, such as iopromide. It was found that using a revolution rate of 240 rev/min, a flow rate of 25 µL/min and a translational speed of 0.033 cm/s resulted in visually uniform coatings. High performance liquid chromatography (HPLC) allowed for the determination of paclitaxel content on the balloon surface. Scanning electron microscopy (SEM) enabled analysis of coating thickness and texture at distal, middle, and proximal positions on the balloon; average thicknesses were determined to be 16.4 ± 5.8, 14.8 ± 1.4, and 18.1 ± 3.9 µm, respectively. These optimized coating conditions have been confirmed by in vitro drug release kinetics studies. Overall this study generated a simple and reproducible micro-pipetting coating method for the sustained release of drugs from the drug coated balloons.

Intravascular Ultrasound-Guided Percutaneous Stenting for Treatment of LVAD Outflow Graft Obstruction

Introduction Left ventricular assist device (LVAD) outflow graft obstruction is a well-known and significant complication. The typical management involves treatment of presumed thrombosis of the graft with intensified anticoagulation or surgery. More recently, endovascular stenting has been reported as a possible treatment option. We describe the management of a LVAD outflow cannula obstruction with never reported intravascular ultrasound (IVUS)-guided covered endovascular stenting. Case report A 68 year-old female with non-ischemic cardiomyopathy status-post LVAD implantation in March 2016 presented with persistent symptomatic low flow alarms and clinical signs of heart failure. Symptoms seemed to worsen when she laid on her right side. She was compliant with her anticoagulation and lactate dehydrogenase level was found to be near her baseline. A CT scan with IV contrast revealed intraluminal obstruction of the LVAD outflow graft secondary to a kinked portion of the outflow cannula near the bend relief with a possible thrombotic component. The severe angulation of the cannula likely developed due to the patient's gradual weight gain of 28kg in the 24 months since LVAD implantation. Given the patient's risk profile, a percutaneous endovascular stenting approach was taken. IVUS was used to visualize the obstruction and kinking of the graft. A balloon-expandable covered stent was deployed at the stenotic site while the LVAD was briefly stopped to avoid stent/balloon migration. A covered stent was used to minimize the risk of thrombus migration/extrusion. IVUS was used again after post-dilation of the stent to confirm placement with no thrombus extrusion. Several hours later the patient had recurrent low-flow alarms. A repeat CT scan revealed that the kink had migrated and been transmitted within the outflow cannula towards the LVAD. The patient returned to the angiography suite where 2 balloon expandable stents were deployed more proximally within the outflow cannula and in an overlapping fashion with the original covered stent. Non-covered stents were used for the second procedure as there was no suspected thrombotic component. IVUS showed no significant residual kinking post-stenting. This was confirmed with a repeat CT scan. The patient recovered without any hemodynamic or neurologic sequelae. Conclusion Percutaneous endovascular stenting is an emerging option for treatment of outflow tract obstruction in LVAD patients that are not candidates for surgery. IVUS can be a valuable tool during intervention to confirm proper stent position, thrombus isolation, and outflow cannula geometry.

A refractory hypertensive patient with fibromuscular dysplasia and multicystic dysplastic kidney

The case of a 16-year-old male patient with left renal artery stenosis due to fibromuscular dysplasia (FMD) and an atrophic kidney due to a right multicystic dysplastic kidney (MCDK) who presented with refractory hypertension is reported. On continuous Doppler imaging, the peak systolic velocity (PSV) at the stenotic site of the left renal artery was 404cm/s. The FMD formed a "string-of-beads" appearance on computed tomographic angiography (CTA) and renal artery angiography. Percutaneous transluminal renal angioplasty (PTRA) with a balloon catheter was performed, after which the left renal artery returned to near normal, and his blood pressure decreased to within the normal range. In this case, the main cause of refractory hypertension was considered to have been renal artery stenosis due to left FMD.

Plaque Morphology as Predictor of Late Plaque Events in Patients With Asymptomatic Type 2 Diabetes: A Long-Term Observational Study

ObjectivesThe authors used coronary computed tomography angiography (CTA) to determine plaque characteristics predicting individual late plaque events precipitating acute coronary syndromes (ACS) in a cohort of asymptomatic type 2 diabetic patients. BackgroundIn patients with coronary artery disease, CTA plaque characteristics may predict mid-term patient events. MethodsAsymptomatic patients with diabetes 55 to 74 years of age with no history of coronary artery disease (N = 630) underwent baseline 64-slice CTA and detailed plaque level analysis. All subsequent clinical events were recorded and adjudicated. In patients who developed ACS, culprit plaque was identified at invasive angiography and its precursor located on the baseline CTA. Plaque characteristics predicting an ACS-associated culprit plaque event were analyzed by time to event accounting for inpatient clustering of plaques and competing events. ResultsAmong 2,242 plaques in 499 subjects, 24 ACS culprit plaques were identified in 24 subjects during median follow-up of 9.2 years (interquartile range: 8.4 to 9.8 years). Plaque volume (upper vs. lower quartile hazard ratio [HR]: 6.9; 95% confidence interval [CI]: 1.6 to 30.8; p = 0.011), percentage of low-density plaque content <50 Hounsfield units (HR: 14.2; 95% CI: 1.9 to 108; p = 0.010), and mild plaque calcification (HR vs. all other plaques 3.3 [95% CI: 1.5 to 7.3]; p = 0.004) predicted plaque events univariately and after adjustment by clinical risk score. A culprit plaque event occurred in 13 of 376 (3.5%) high-risk plaques (HRP) (plaques with ≥2 risk predictors) versus 11 of 1,866 (0.6%) in non-HRPs (p < 0.0001), at 12 of 343 (3.5%) stenotic sites (≥50%) versus 12 of 1,899 (0.6%) nonstenotic sites (p < 0.0001) and in 7 of 131 (5.3%) HRP with stenosis (p < 0.0001 vs. all others). In 130 (20.6%) subjects, no coronary plaque was present on baseline CTA. ConclusionsIn asymptomatic patients with type 2 diabetes, CTA plaque volume, percent low-density plaque content, and mild calcification predicted late plaque events. The additional presence of luminal stenosis increased the probability of an acute event.

Settlement of Stenotic Site and Enhancement of Risk Factor Load for Atherosclerosis in Left Anterior Descending Coronary Artery by Myocardial Bridge.

The aim of this study was to investigate the influence of a myocardial bridge (MB) on atherosclerosis development in the left anterior descending artery of the normal heart and the importance of traditional risk factors (RFs). An additional objective was to determine the correlation between intimal thickening and luminal narrowing. The left anterior descending artery from 150 autopsied hearts was treated with formalin perfusion fixation, and each left anterior descending artery was serially cross-sectioned. The intima-media and luminal stenosis ratios were examined using computer-assisted histomorphometry. The luminal stenosis ratio was closely correlated with the intima-media ratio (r=0.792; P<0.001). When an MB was present, the luminal stenosis ratios proximal to the MB in the RF (+) group were significantly greater than those in the RF (-) group (P=0.022 by a multiple comparison test), but there were no differences between the RF (+) and RF (-) groups when an MB was absent. In addition, the site of the greatest stenosis in the MB (+) RF (+) group was 2.5 cm proximal to the MB entrance. Multivariate analyses indicated that age was an independent factor for luminal stenosis ratios ≥50% and 60% (P=0.002 and 0.029, respectively). Furthermore, the presence of an MB plus RFs was an independent factor for a luminal stenosis ratio ≥70% (P=0.037). An MB enhances left anterior descending artery atherosclerosis development at a site proximal to the MB entrance, particularly in subjects who have some RFs.

Extracranial carotid doppler correlation to multidetector CT angiography in ischemic stroke patients

The purpose of this study was to compare the diagnostic value of Color Doppler Ultrasound (CDUS), Computed Tomographic Angiography (CTA), and advantage of their combined use in defining the degree of stenosis and morphological character of atheromatous plaque in ischemic stroke patients. This was a cross-sectional study with a total of 60 patients having 120 carotid arteries were observed. The percentage of stenosis was measured at the narrowest point by modified NASCET criteria for both CDUS & CTA. Incidence of stroke was highest in the age group 50-70years with male population commonly affected. Frequency of carotid stenosis was more in male patients aged above 60 years. Hemiparesis was most common symptoms in stroke patients. The various risk factors of carotid atherosclerosis and stenosis included hypertension, diabetes mellitus, hyperlipidemia and cardiovascular disease. Atheromatous plaques with stenosis were most commonly found on right side. Carotid bifurcation was the common site for atheromatous plaque .There was significant correlation between Color Doppler Ultrasound and Computed Tomographic Angiography for detecting 70-100% stenosis. However CTA is more accurate in comparison to duplex ultrasonography in detecting 70-99% stenosis and total occlusion. There was no significant correlation between CDUS and CTA in detecting 20-49% stenosis. Duplex ultrasonography is more sensitive in detecting these lesions. Out of 49 plaques, in this study 11 were soft plaques, 26 were non-homogenous and 13 were ulcerative plaques. Color doppler has better role in plaque characterization. Besides degree of extracranial stenosis, length of the stenosis, site of intracranial stenosis and total number of stenotic sites are better assessed by CTA. Area of effected brain parenchyma and extent of collateral circulation are better assessed by CTA which aids in prognostic value. In conclusion, the advantage of the combined use of CDUS and the CTA in the identification and quantification of ICA stenosis is higher. However ultrasound had a better role in plaque characterization.