Measurement Of Lumen Diameter Research Articles

Abstract P338: Impaired Endothelial-Dependent Vasorelaxation and Myogenic Response in Renal Afferent Arterioles of Diabetic mice: Role of Endothelial NOX1, and New Gene Pathways.

Diabetes increases the risk of cardiovascular disease and hypertension, in part, by decreasing arterial vasodilation through decreased NO bioavailability and increased superoxide. In the kidney, type 1 diabetes induces a decrease in renal filtration, proteinuria, inflammation, and fibrosis, increasing the incidence of kidney disease. In diabetic rats and rabbits, prone to renal disease, diabetes blunts acetylcholine (Ach)-induced vasorelaxation of afferent arterioles, in part, by enhancing endothelial superoxide. However, it is unclear whether diabetes affects afferent arteriole vasodilation and myogenic response in mice. We hypothesize that diabetes increases endothelial NOX1 mediated superoxide production in mouse afferent arterioles, decreasing Ach-induced vasodilation. We dissected and perfused afferent arterioles from male diabetic Akita mice 12-14 weeks of age and measured the effect Ach (10 -7 -10 -5 M) on luminal diameter after pre-constriction with norepinephrine. Diabetic Akita mice had a largely reduced Ach-induced dilation at all doses of Ach (80±6% average inhibition in dilation, p<0.025, n=6). To study the role of NOX1, we used the inhibitor ML171 (5µM). When added to the endothelial lumen, NOX1 inhibition completely restored Ach-induced dilation of diabetic Akita mice, which was not different from WT controls. In Control C57 mice, ML171 did not change Ach-induced dilation in Aff-Art (n=6). We then examined the myogenic response in diabetic mice by measuring lumen diameter after step increases in perfusion pressure (60-140 mmHg). Afferent arterioles of diabetic Akita mice did not constrict when pressure was increased, even at 140 mmHg, whereas WT mice showed normal myogenic response (delta constriction 60-140 mmHg WT: 2.15±0.41 vs Akita: 0.37±0.32 µm, WT p<0.01 from baseline, Akita n.s from baseline). To understand the mechanisms behind these effects we performed RNAseq in manually micro-dissected afferent arterioles from 12-week-old Akita and WT mice. Bioinformatics analysis showed 530 DEGs (FDR pAdj<0.05, n=6). Most of the DEGs are involved in endothelial cell function/metabolism, smooth muscle cell contractility, activated inflammatory pathways, and free radical/NO production. We conclude that early diabetes has a large effect on renal afferent arteriole reactivity by affecting the expression of hundreds of genes. These effects are likely involved in hypertension and kidney damage progression in type 1 diabetes.

Optimization of pulmonary artery mechanical testing

Pulmonary arterial hypertension (PAH) is an incurable disease with mortality within 3 years in 28-55% of high-risk patients. The progression of PAH has been known to be associated with increased vascular stiffness and vascular remodeling. Recent studies have suggested that increased stiffness may in fact be a driver for some of the metabolic abnormalities observed during PAH. To gain more insights into this relationship, we need to quantify the differences in mechanical properties of healthy and hypertensive pulmonary arteries. The stress-strain relationship is the gold standard for the ex-vivo stiffness measurement of arteries. This is obtained by obtaining force vs. distension data by tensile testing and using sample dimensions, i.e. length, lumen diameter, and wall thickness, to calculate engineering stress and strain. While this approach is well-optimized for large muscular arteries, it has not been used to test pulmonary arteries as their thin walls and low basal tone make it challenging to make precise measurements of sample wall thickness and lumen diameter. Thus, the goals of this study were to: 1) establish a reliable protocol for rat pulmonary artery tensile testing and 2) quantify the differences in stiffness between hypertensive and healthy pulmonary arteries. First, a methodology to improve the fidelity of determining the lumen diameter and wall thickness was developed. Using this approach, we observed that the modulus was negatively correlated with the length of the vessel segment tested. This suggests that vessel length should be standardized to perform reliable comparisons between groups. Next, we performed tensile tensing on both control and hypertensive pulmonary arteries, after standardizing vessel segment lengths. We initially modeled this tensile testing data using a one-term exponential equation and we observed that intact hypertensive arteries were ~2.7 times stiffer than control arteries at low strain (strain = 0.8). Whereas at high strain (strain = 2.8) intact and decellularized hypertensive arteries were 20 and 29 times stiffer than control arteries respectively. To better capture the viscoelastic properties of both, the cellular and ECM components of the vessels we also fit the tensile testing data using a two-term exponential equation. Using this two-term exponential model, we observed that hypertensive vessels were 2.2 times stiffer than the controls at normal hoop stress (20 kPa), and at the hypertensive hoop stress (66 kPa) the diseased vessels showed less variability in stiffness as compared to the controls. These findings and the methods developed in this study will be helpful in conducting and analyzing experiments to investigate the relationship between changes in biomechanical signals and the progression of PAH. R01HL151530 (KS), R01HL126514 (LS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Adaptive vessel tracing and segmentation in OCT enables the robust detection of wall-to-lumen ratio abnormalities in 5xFAD mice.

The wall-to-lumen ratio (WLR) of retinal blood vessels promises a sensitive marker for the physiological assessment of eye conditions. However, in vivo measurement of vessel wall thickness and lumen diameter is still technically challenging, hindering the wide application of WLR in research and clinical settings. In this study, we demonstrate the feasibility of using optical coherence tomography (OCT) as one practical method for in vivo quantification of WLR in the retina. Based on three-dimensional vessel tracing, lateral en face and axial B-scan profiles of individual vessels were constructed. By employing adaptive depth segmentation that adjusts to the individual positions of each blood vessel for en face OCT projection, the vessel wall thickness and lumen diameter could be reliably quantified. A comparative study of control and 5xFAD mice confirmed WLR as a sensitive marker of the eye condition.

Semiautomated Segmentation and Analysis of Airway Lumen in Pediatric Patients Using Ultra Short Echo Time MRI

Ultra short echo time (UTE) magnetic resonance imaging (MRI) pulse sequences have shown promise for airway assessment, but the feasibility and repeatability in the pediatric lung are unknown. The purpose of this work was to develop a semiautomated UTE MRI airway segmentation pipeline from the trachea-to-tertiary airways in pediatric participants and assess repeatability and lumen diameter correlations to lung function. A total of 29 participants (n=7 healthy, n=11 cystic fibrosis, n=6 asthma, and n=5 ex-preterm), aged 7-18 years, were imaged using a 3D stack-of-spirals UTE examination at 3 T. Two independent observers performed airway segmentations using a pipeline developed in-house; observer 1 repeated segmentations 1 month later. Segmentations were extracted using region-growing with leak detection, then manually edited if required. The airway trees were skeletonized, pruned, and labeled. Airway lumen diameter measurements were extracted using ray casting. Intra- and interobserver variability was assessed using the Sørensen-Dice coefficient (DSC) and intra-class correlation coefficient (ICC). Correlations between lumen diameter and pulmonary function were assessed using Spearman's correlation coefficient. For airway segmentations and lumen diameter, intra- and interobserver DSCs were 0.88 and 0.80, while ICCs were 0.95 and 0.89, respectively. The variability increased from the trachea-to-tertiary airways for intra- (DSC: 0.91-0.64; ICC: 0.91-0.49) and interobserver (DSC: 0.84-0.51; ICC: 0.89-0.21) measurements. Lumen diameter was significantly correlated with forced expiratory volume in 1secondand forced vital capacity (P<.05). UTE MRI airway segmentation from the trachea-to-tertiary airways in pediatric participants across a range of diseases is feasible. The UTE MRI-derived lumen measurements were repeatable and correlated with lung function.

PREDICTION OF CAROTID INTIMA MEDIA THICKNESS AND STIFFNESS IN ADOLESCENCE AND YOUNG ADULTHOOD FROM FOUR BLOOD PRESSURE PARAMETERS AND RESTING HEART RATE

Objective: Childhood blood pressure (BP) is associated with hard outcomes and intermediate markers of cardiovascular disease several decades later but studies on more short-termed outcomes are scarce and and it is unclear whether different BP parameters are all predictive. This study investigates the association of four BP parameters and resting heart rate (RHR) at age 3 - 17 years with three carotid markers one decade later with population-based data. Design and method: 4,607 14- to 28-year old participants of the nationwide German pediatric cohort KiGGS had semi–automated sonography with measurements of carotid intima media thickness (CIMT), lumen diameter (LD) and distensibility coefficient (DC) at their 11-year follow–up. We investigated associations of both baseline and follow-up systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), pulse pressure (PP) and RHR, with CIMT and LD &gt; = 90th percentile and DC &gt; = 10th percentile in logistic regression models. Percentiles were computed by sex and age. Analyses were adjusted for a cardiovascular risk score from added z-scores of body mass index, triglycerides, total-/HDL-cholesterol-ratio and HbA1c. Results: In longitudinal analyses SBP, DBP, MAP and RHR were significantly associated with all measures of subclinical atherosclerosis 11 years later, with similar, however weak, effect estimates, e.g. an OR of 1.19 (CI 1.09 - 1.31) for a one standard deviation increase in SBP with elevated CIMT. Cross–sectionally, the strongest association was found for MAP with reduced DC (OR 1.76; CI 1.60 - 1.94). For PP not all of these associations were significant. RHR was associated with elevated LD and reduced DC and inversely associated with elevated CIMT. Associations were similar when adjusting for the composite cardiovascular risk score. Conclusions: This study fills a gap between previous findings of an association between childhood BP and adverse effects in the vasculature in mid-adulthood, several decades later, by giving evidence for the association already after one decade. While individual risk prediction based of single BP measurements in this study is only weak, its robustness and consistency over five haemodynamic parameters and three subclinical atherosclerosis measures underscore the importance of preventing high blood pressure already early in the life course.

Simultaneous Highly Efficient Contrast-Free Lumen and Vessel Wall MR Imaging for Anatomical Assessment of Aortic Disease.

Bright-blood lumen and black-blood vessel wall imaging are required for the comprehensive assessment of aortic disease. These images are usually acquired separately, resulting in long examinations and potential misregistration between images. To characterize the performance of an accelerated and respiratory motion-compensated three-dimensional (3D) cardiac MRI technique for simultaneous contrast-free aortic lumen and vessel wall imaging with an interleaved T2 and inversion recovery prepared sequence (iT2Prep-BOOST). Prospective. A total of 30 consecutive patients with aortopathy referred for a clinically indicated cardiac MRI examination (9 females, mean age ± standard deviation: 32 ± 12 years). 1.5-T; bright-blood MR angiography (diaphragmatic navigator-gated T2-prepared 3D balanced steady-state free precession [bSSFP], T2Prep-bSSFP), breath-held black-blood two-dimensional (2D) half acquisition single-shot turbo spin echo (HASTE), and 3D bSSFP iT2Prep-BOOST. iT2Prep-BOOST bright-blood images were compared to T2prep-bSSFP images in terms of aortic vessel dimensions, lumen-to-myocardium contrast ratio (CR), and image quality (diagnostic confidence, vessel sharpness and presence of artifacts, assessed by three cardiologists on a 4-point scale, 1: nondiagnostic to 4: excellent). The iT2Prep-BOOST black-blood images were compared to 2D HASTE images for quantification of wall thickness. A visual comparison between computed tomography (CT) and iT2Prep-BOOST was performed in a patient with chronic aortic dissection. Paired t-tests, Wilcoxon signed-rank tests, intraclass correlation coefficient (ICC), Bland-Altman analysis. A P value < 0.05 was considered statistically significant. Bright-blood iT2Prep-BOOST resulted in significantly improved image quality (mean ± standard deviation 3.8 ± 0.5 vs. 3.3 ± 0.8) and CR (2.9 ± 0.8 vs. 1.8 ± 0.5) compared with T2Prep-bSSFP, with a shorter scan time (7.8 ± 1.7minutes vs. 12.9 ± 3.4minutes) while providing a complementary 3D black-blood image. Aortic lumen diameter and vessel wall thickness measurements in bright-blood and black-blood images were in good agreement with T2Prep-bSSFP and HASTE images (<0.02 cm and <0.005 cm bias, respectively) and good intrareader (ICC > 0.96) and interreader (ICC > 0.94) agreement was observed for all measurements. iT2Prep-BOOST might enable time-efficient simultaneous bright- and black-blood aortic imaging, with improved image quality compared to T2Prep-bSSFP and HASTE imaging, and comparable measurements for aortic wall and lumen dimensions. 2. Stage 2.

Clinical Impact of the Size of Drug-Coated Balloon Therapy on Restenosis Rate in Femoropopliteal Lesions

Purpose: Although the size of drug-coated balloons (DCBs) is determined according to the vessel diameter during femoropopliteal (FP)-endovascular therapy (EVT), the measurements of the vessel diameter vary among modalities and its definitions. The aim of this study was to reveal whether the DCB size fitting (1) angiographically-measured lumen diameter (Angio-lumen size), (2) intravascular ultrasound (IVUS)-measured lumen diameter (IVUS-lumen size), or (3) IVUS-measured external elastic membrane (EEM) diameter (IVUS-EEM size) would be beneficial in restenosis occurrence. Materials and Methods: This retrospective, single-center study included 231 de novo FP lesions in 165 patients with peripheral artery disease treated with IN.PACT Admiral DCB under IVUS evaluation. The reference vessel diameter was evaluated as the lumen or EEM diameter at the healthy site distal to the lesion. We retrospectively determined whether the DCB size was close to (ie, equal to or different by <0.5 mm from) Angio-lumen size, IVUS-lumen size, and IVUS-EEM size. The association of the size of DCB with restenosis risk was investigated. Results: The mean lesion length was 13 ± 9 cm and the prevalence of chronic total occlusion was 18%. During a mean follow-up period of 17 ± 9 months, restenosis occurred in 26% of lesions. Lesions treated with a DCB of IVUS-EEM size had a lower 2 year restenosis rate than those treated with a DCB over/under IVUS-EEM size (19.7 ± 5.7% vs 34.5 ± 4.7%, p=0.02 by the log-rank test), while the restenosis rate was not significantly different between DCBs of Angio-lumen size or IVUS-lumen size and those over/under the size (both p>0.05). The multivariate Cox regression analysis revealed that DCBs of IVUS-EEM size were independently associated with a reduced risk of restenosis (adjusted hazard ratio 0.50; 95% confidence interval 0.27–0.95; p=0.03). Conclusion: The DCBs of IVUS-EEM size, but not of Angio-lumen size or IVUS-lumen size, were associated with a reduced risk of restenosis after FP-EVT. Determining the DCB size according to IVUS-evaluated EEM diameter would be potentially beneficial in restenosis occurrence.

A Machine Learning Pipeline for Measurement of Arterial Stiffness in A-Mode Ultrasound.

Arterial stiffness (AS) of the carotid artery is an early marker of stratifying cardiovascular disease risk. This article aims to improve the performance of ARTSENS, a noninvasive A-mode ultrasound-based device for measuring AS. The primary objective of ARTSENS is to enable the measurement of elastic modulus using A-Mode ultrasound and blood pressure. As this device is image-free, there is a need to automate: 1) carotid detection; 2) wall localization; and 3) inner lumen diameter measurement. This has been performed using conventional signal processing methods in some of the earlier works in this domain. In this article, deep neural network (DNN) models are employed to perform the above three tasks. The DNNs were trained over data acquired from 82 subjects at two different medical centers. Ground-truth labeling was performed by a trained operator using corresponding measurements from the state-of-the-art Aloka e-Tracking system. All three DNN models had significantly lower errors compared to earlier signal processing methods and could perform their measurements using a single A-Mode frame. Using the DNNs, two different machine learning pipelines have been proposed here to measure the elastic modulus; the best among them could achieve an error of 9.3% with the Pearson correlation coefficient of 0.94 ( ). The models were tested on Raspberry Pi and Jetson Nano single board computers to demonstrate real-time processing on low computational resources.

Diameter measurements in three-dimensional printed flow phantom model of the carotid artery in preterm infants

Diameter form an integral part of blood flow measurement. This study aimed to explore different three-dimensional (3D) printed materials to develop flow phantom models of the carotid artery in preterm newborn infants and to investigate ideal diameter measurement points using ultrasound that reflected accurate lumen diameter measurement.&#x0D; Cerebral blood flow measurements data using Doppler ultrasound of the right common carotid artery from 21 randomly selected preterm infants were used to produce a 3D printed Doppler flow phantom model with three different vessel diameters. Diameters were measured by multiple observers blinded to phantom vessel characteristics and each other’s measurements. 9 measurement points were studied. Agreement between observers, inter and intra observer reliability and coefficient of variation (CoV) was examined.&#x0D; Of the 63 diameter measurements, 45 (71%) were performed on flow phantoms with vessel diameter of 0.196 cm. Bland-Altman plots revealed that measurement performed using leading edge to centre (mean bias 1.8% {95%LOA -4.1% to 7.7%}) and centre to trailing edge (mean bias 1.1% {95%LOA -5.4% to 7.8%}) resulted in the most accurate lumen diameter measurements. Inter and intra-observer reliability was excellent. The mean CoV for inter observer measurements was 1.7% and intra observer measurements was 1.6% and 1.8% for each observer.&#x0D; We successfully produced a 3D printed flow phantom model of the carotid artery in preterm infants and identified two measurement methods that result in reliable and accurate lumen diameter measurement. Researchers and clinicians can use this information for further studies involving ultrasound diameter measurements in small calibre vessels.

Hypertrophic remodelling of retinal arterioles in patients with congestive heart failure.

AimsAnalysis of microvascular parameters in the retinal circulation—known to reflect those in the systemic circulation—allows us to differentiate between eutrophic and hypertrophic remodelling of small arteries. This study aimed to examine microvascular changes in patients with congestive heart failure (CHF) and reduced as well as mid‐range ejection fraction.Methods and resultsForty subjects with CHF underwent measurement of retinal capillary flow (RCF), wall‐to‐lumen ratio (WLR), vessel and lumen diameter, wall thickness, and wall cross‐sectional area (WCSA) of retinal arterioles of the right eye by scanning laser Doppler flowmetry (SLDF). Applying a matched pair approach, we compared this group with reference values of age‐matched controls from a random sample in the population of Pilsen, Czech Republic. There was no significant difference in RCF and WLR between the groups (RCF: P = 0.513; WLR: P = 0.106). In contrast, wall thickness and WCSA, indicators of hypertrophic remodelling, were higher in CHF subjects (WT: 15.0 ± 4.2 vs. 12.7 ± 4.2 μm, P = 0.021; WCSA: 4437.6 ± 1314.5 vs. 3615.9 ± 1567.8 μm2, P = 0.014). Similarly, vessel (109.4 ± 11.1 vs. 100.5 ± 14.4 μm, P = 0.002) and lumen diameter (79.0 ± 7.9 vs. 75.2 ± 8.5 μm, P = 0.009) were increased in CHF.ConclusionsIn CHF subjects, we observed hypertrophic remodelling of retinal arterioles indicative of similar changes of small resistance arteries in the systemic circulation. Microvascular structure and function assessed by SLDF may thereby represent a useful, non‐invasive method for monitoring of microvascular damage in patients with CHF and may offer innovative treatment targets for new CHF therapies.

APRIL: Anatomical prior-guided reinforcement learning for accurate carotid lumen diameter and intima-media thickness measurement

Carotid artery lumen diameter (CALD) and carotid artery intima-media thickness (CIMT) are essential factors for estimating the risk of many cardiovascular diseases. The automatic measurement of them in ultrasound (US) images is an efficient assisting diagnostic procedure. Despite the advances, existing methods still suffer the issue of low measuring accuracy and poor prediction stability, mainly due to the following disadvantages: (1) ignore anatomical prior and prone to give anatomically inaccurate estimation; (2) require carefully designed post-processing, which may introduce more estimation errors; (3) rely on massive pixel-wise annotations during training; (4) can not estimate the uncertainty of the predictions. In this study, we propose the Anatomical Prior-guided ReInforcement Learning model (APRIL), which innovatively formulate the measurement of CALD & CIMT as an RL problem and dynamically incorporate anatomical prior (AP) into the system through a novel reward. With the guidance of AP, the designed keypoints in APRIL can avoid various anatomy impossible mis-locations, and accurately measure the CALD & CIMT based on their corresponding locations. Moreover, this formulation significantly reduces human annotation effort by only using several keypoints and can help to eliminate the extra post-processing steps. Further, we introduce an uncertainty module for measuring the prediction variance, which can guide us to adaptively rectify the estimation of those frames with considerable uncertainty. Experiments on a challenging carotid US dataset show that APRIL can achieve MAE (in pixel/mm) of 3.02±2.23 / 0.18±0.13 for CALD, and 0.96±0.70 / 0.06±0.04 for CIMT, which significantly surpass popular approaches that use more annotations.

OF-UMRN: Uncertainty-guided multitask regression network aided by optical flow for fully automated comprehensive analysis of carotid artery.

Fully automated comprehensive analysis of carotid artery (localization of range of interest (ROI), direct quantitative measurement and segmentation of lumen diameter (CALD) and intima-media thickness (CIMT), and motion estimation of the carotid wall) is a reliable auxiliary diagnosis of cardiovascular diseases, which relieves physicians from laborious workloads. No work has achieved fully automated comprehensive analysis of carotid artery due to five intractable challenges: (1) The heavy reliance on experienced carotid physicians for the selection of ROI limits fully automated studies. (2) The weak structural information of intima-media thickness increases the difficulty of feature encoding. (3) The radial motion of the carotid wall results in the lack of discriminant features of boundaries. (4) Diseased carotid arteries lose many expression features. (5) Optimal weights of multitask regression are hard to tune manually. In this paper, we propose a novel uncertainty-guided multitask regression network aided by optical flow named OF-UMRN to solve the intractable challenges. The four modules and three innovations of the OF-UMRN take their responsibility. OF-UMRN takes localization and mapping of ROI as a pre-processing. It achieves direct quantitative measurement and segmentation by a multitask regression network. And we creatively model homoscedastic uncertainty to automated tune the weights of the two tasks optimally. The OF-UMRN adopts a bidirectional mechanism to encode the optical flow used to predict the carotid wall's motion fields. More importantly, we creatively propose a dual optimization module based on the co-promotion between segmentation and motion estimation to improve the performance of radially moving and diseased carotid arteries. Therefore, the OF-UMRN makes the most of the pathological relationship between multiple objects and co-promotion between various tasks. Extensive experiments on US sequences of 101 patients have demonstrated the superior performance of OF-UMRN on the fully automated comprehensive analysis of the carotid artery. Therefore the OF-UMRN has excellent potential in clinical disease diagnoses and assessments of the carotid artery.

External elastic lamina vs. luminal diameter measurement for determining stent diameter by optical coherence tomography: an ILUMIEN III substudy.

Optical coherence tomography (OCT)-guided external elastic lamina (EEL)-based stent sizing is safe and as effective as intravascular ultrasound in achieving post-procedural lumen dimensions. However, when compared with automated lumen diameter (LD) measurements, this approach is time-consuming. We aimed to compare vessel diameter measurements and stent diameter selection using either of these approaches and examined whether applying a correction factor to automated LD measurements could result in selecting similar stent diameters to the EEL-based approach. We retrospectively compared EEL-based measurements vs. automated LD in reference segments in 154 OCT acquisitions and derived a correction factor for stent sizing using the ratio of EEL to LD measurements. We then prospectively applied the correction factor in 119 OCT acquisitions. EEL could be adequately identified in 100 acquisitions (84%) at the distal reference to allow vessel diameter measurement. Vessel diameters were larger with EEL-based vs. LD measurements at both proximal (4.12 ± 0.74 vs. 3.14 ± 0.67 mm, P < 0.0001) and distal reference segments (3.34 ± 0.75 vs. 2.64 ± 0.65 mm, P < 0.0001). EEL-based downsizing led to selection of larger stents vs. an LD-based upsizing approach (3.33 ± 0.47 vs. 2.70 ± 0.44, P < 0.0001). Application of correction factors to LD [proximal 1.32 (IQR 1.23-1.37) and distal 1.25 (IQR 1.19-1.36)] resulted in discordance in stent sizing by >0.25 mm in 63% and potentially hazardous stent oversizing in 41% of cases. EEL-based stent downsizing led to selection of larger stent diameters vs. LD upsizing. While applying a correction factor to automated LD measurements resulted in similar mean diameters to EEL-based measurements, this approach cannot be used clinically due to frequent and potentially hazardous stent over-sizing.

Effect of L-Arginine Therapy on Vasospasm: Experimental Study in Rats

Cerebral vasospasm occurring after subarachnoid hemorrhage is a serious cause of morbidity. Cerebral vasospasm-related studies aim to prevent complications after subarachnoid hemorrhage. Nitric oxide affects brain blood flow and local vascular hemodynamics. L-arginine is used in the synthesis of nitric oxide, and hence we have investigated the efficacy of L-arginine treatment by using femoral artery vasospasm model. Twenty-four male Sprague-Dawley rats have been divided into 3 groups as vasospasm, vasospasm+ L-arginine, and control. In this study, we have preferred the "Rat Femoral Artery Vasospasm Model" described by Okada etal. Rats in the vasospasm+ L-arginine group were given 300 mg/kg L-arginine for 7 days. At the end of the study, all samples of rat femoral arteries have been dissected and examined microscopically for histopathologic analysis. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U tests, and P < 0.05 value was considered statistically significant. L-arginine treatment reduced the morphometric changes such as irregularity of the elastic lamina, disruption of the endothelial cells, vacuolization, and hemorrhages that are caused by vasospasm. When the wall thickness and lumen diameter measurements were evaluated statistically, significant improvement was observed in the vasospasm+ L-arginine group compared with the vasospasm group (P < 0.01). In our study, the use of L-arginine, as a nitric oxide substrate, improved the experimental vasospasm in rats. Therefore we think that L-arginine therapy can be used in the prevention and treatment of cerebral vasospasm after subarachnoid hemorrhage.

Continuous Assessment of Carotid Diameter using an Accelerometer Patch Probe for Ambulatory Arterial Stiffness Monitoring.

We present a system with an accelerometer patch probe design for non-invasive evaluation of carotid arterial stiffness. The proposed system could continuously measure the acceleration signal derived due to the propagation of blood pulse wave through the left carotid artery, double integrating and scaling it to estimate the accelerometer-derived carotid wall displacement. This functional principle was proved by comparing the accelerometer-derived carotid wall displacement with the carotid distension signal from the reference system ARTSENS® (ARTerial Stiffness Evaluation for Noninvasive Screening device) for all the recruited human subjects. Assuming the relationship to be linear, a one-time subject-specific calibration was performed with the simultaneously acquired reference distension signal and the accelerometer-derived carotid displacement signals on its anachrotic limbs data points (at systolic phases) for each subject. This calibration equation was tested with latterly acquired accelerometer signals and results in the measurement of accelerometer-derived carotid distension and lumen-diameter values. The ability of the accelerometer system to measure real-time carotid distension and lumen diameter in a repeatable beat-by-beat manner for arterial stiffness index evaluation was validated in-vivo. The accuracy of the obtained results was studied with our clinically validated reference system. The experimental validation study results exhibit the feasibility of using the developed accelerometer system for continuous carotid distension and lumen diameter measurements, whereby the estimation of carotid arterial stiffness.

Structural coronary artery remodelling in the rabbit fetus as a result of intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a fetal condition that affects up to 10% of all pregnancies and is associated with cardiovascular structural and functional remodelling that persists postnatally. Some studies have reported an increase in myocardial coronary blood flow in severe IUGR fetuses which has been directly associated to the dilatation of the coronary arteries. However, a direct measurement of the coronaries’ lumen diameter in IUGR has not been reported before. The aim of this paper is to perform, for the first time, a quantitative analysis of the effects of IUGR in cardiac geometry and coronary vessel size in a well-known rabbit model of IUGR using synchrotron-based X-ray Phase Contrast Tomography Imaging (X-PCI). Eight rabbit fetal hearts were imaged non-destructively with X-PCI. 3D reconstructions of the coronary arterial tree were obtained after semi-automatic image segmentation. Different morphometric features including vessel lumen diameter of the three main coronaries were automatically quantified. IUGR fetuses had more globular hearts and dilated coronary arteries as compared to controls. We have quantitatively shown that IUGR leads to structural coronary vascular tree remodelling and enlargement as an adaptation mechanism in response to an adverse environment of restricted oxygen and nutrients and increased perfusion pressure.

Emblica officinalis (Amla) Ameliorates High-Fat Diet Induced Alteration of Cardiovascular Pathophysiology.

Background:Dietary high fat possibly causes oxidative stress. Also, it alters the pathophysiology of metabolically active myocardial tissues and vascular architecture. Emblica officinalis contains a potential antioxidant that counteracts oxidative stress and possibly maintains vascular integrity.Objectives:To assess the effect of ethanolic extract of Emblica officinalis (EEO) on High Fat Diet (HFD) induced changes in vascular chemistry and histopathology of the cardiovascular system in male albino rats.Materials and Methods:Ethanolic extract of Emblica Officinalis (EEO) was prepared and phytochemical analysis was done. Rats were divided into four groups, having six rats in each group as follows: group 1- Control (20% fat); group 2 (20% fat+ EEO 100 mg/kg/b w); group 3 (30% fat) and group 4 (30% fat + EEO 100 mg/kg/b w). Dietary and EEO supplementation was continued for 21 days. Gravimetric and oxidative stress markers like MDA, NO, antioxidants like Vitamin C and E, and molecular marker (NOS3) were evaluated. Histopathological analysis was done on the myocardium and elastic artery along with measurement of coronary arterial wall thickness and lumen diameter. One way ANOVA was done for analysis of data.Results:High fat diet showed a significant increase in MDA, decrease of NO with unaltered NOS3 protein in rats fed with high fat diet, which indicate possible alteration of vascular pathophysiology. Supplementation of EEO showed an ameliorating effect on high fat diet induced oxidative stress. These results were further corroborated with findings of a histopathological study on the myocardium, elastic artery and coronary arterial architecture.Conclusion:Ethanolic extract of Emblica officinalis (EEO) indicates its cardioprotective efficacy against rats fed with high fat diet.

Angiography‐Based Machine Learning for Predicting Fractional Flow Reserve in Intermediate Coronary Artery Lesions

BackgroundAn angiography‐based supervised machine learning (ML) algorithm was developed to classify lesions as having fractional flow reserve ≤0.80 versus >0.80.Methods and ResultsWith a 4:1 ratio, 1501 patients with 1501 intermediate lesions were randomized into training versus test sets. Between the ostium and 10 mm distal to the target lesion, a series of angiographic lumen diameter measurements along the centerline was plotted. The 24 computed angiographic features based on the diameter plot and 4 clinical features (age, sex, body surface area, and involve segment) were used for ML by XGBoost. The model was independently trained and tested by 2000 bootstrap iterations. External validation with 79 patients was conducted. Including all 28 features, the ML model with 5‐fold cross‐validation in the 1204 training samples predicted fractional flow reserve ≤0.80 with overall diagnostic accuracy of 78±4% (averaged area under the curve: 0.84±0.03). The 12 high‐ranking features selected by scatter search were involved segment; body surface area; distal lumen diameter; minimal lumen diameter; length of a lumen diameter <2.0 mm, <1.5 mm, and <1.25 mm; mean lumen diameter within the worst segment; sex; diameter stenosis; distal 5‐mm reference lumen diameter; and length of diameter stenosis >70%. Using those 12 features, the ML predicted fractional flow reserve ≤0.80 in the test set with sensitivity of 84%, specificity of 80%, and overall accuracy of 82% (area under the curve: 0.87). The averaged diagnostic accuracy in bootstrap replicates was 81±1% (averaged area under the curve: 0.87±0.01). External validation showed accuracy of 85% (area under the curve: 0.87).ConclusionsAngiography‐based ML showed good diagnostic performance in identifying ischemia‐producing lesions and reduced the need for pressure wires.

Geometric Total Plaque Area Is an Equally Powerful Phenotype Compared With Carotid Intima-Media Thickness for Stroke Risk Assessment: A Deep Learning Approach

Currently, carotid intima-media thickness (cIMT) and geometric total plaque area (gTPA) are computed manually and thus are tedious and prone to interobserver and intraobserver variabilities. This study presents an intelligence-based automated deep learning (DL)–based technique for carotid wall interface detection, cIMT, and lumen diameter (LD) measurements, followed by a 3D cylindrical approach for TPA measurement. The observers were used for manual tracings of which were then used for the design of two DL-based systems. The DL boundaries for inner lumen wall and outer interadventitial borders were used for computing the cIMT and LD. Using cylindrical approach, we computed the gTPA. Furthermore, we compute the 10-year image-based cIMT and gTPA, using the progression rates. A total of 396 B-mode ultrasound right and left common carotid artery images were taken from 203 patients. The mean cIMT and gTPA using DL1 and DL2 is 0.91 mm, 20.52 mm2 and 0.88 mm, 19.44 mm2, respectively. The coefficient of correlation between gTPA and cIMT using DL1 and DL2 is 0.92 ( P &lt; .001) and 0.94 ( P &lt; .001), respectively. The area under the curve (AUC) for gTPA showed an improvement over cIMT by 14.36% and 12.57% for DL1 and DL2, respectively. The corresponding 10-year risk improvements were 9.09% and 6.26%. Our statistical significance tests successfully passed t test, Mann-Whitney, Wilcoxon, Kolmogorov-Smirnov, and Friedman. The study shows gTPA as an equally powerful carotid risk biomarker like cIMT. Given the cIMT and LD, cylindrical fitting is a fast method for gTPA measurements.

Early Recoil After Balloon Angioplasty of Erection-Related Arteries in Patients With Arteriogenic Erectile Dysfunction

Purpose: To evaluate the incidence of elastic recoil in patients presenting with erectile dysfunction (ED) undergoing endovascular revascularization of the pudendal or penile arteries. Methods: A consecutive series of 21 ED patients (mean age 58.3±9.3 years) undergoing minimally invasive revascularization of 31 arteries was analyzed. ED lesions included the pudendal arteries (n=27) and the penile artery (n=4). Mean lesion length was 20.6±13.9 mm. Minimal lumen diameter (MLD) measurements were assessed at baseline, immediately after balloon angioplasty, and 10 minutes thereafter. Early recoil was defined as an MLD reduction >10%. Elastic recoil with >10% lumen compromise was treated with drug-coated balloons, while severe elastic recoil (>30%) required drug-eluting stents (DES). The International Index of Erectile Function (IIEF-15) score was obtained prior to and 3 months after the procedure to obtain information on functional outcomes subsequent to angioplasty. Results: Mean MLD at baseline was 0.9±0.6 mm, which improved to 2.0±0.9 mm immediately after balloon dilation. At 10 minutes after dilation, the MLD was 1.7±1.0 mm. Elastic recoil was observed in all 31 lesions and resulted in a mean lumen compromise of 21.2%. Severe (>30%) recoil was observed in 14 arteries, which underwent DES therapy. The IIEF-15 score improved from 31.3±11.2 at baseline to 49.8±16.8 (p<0.001) at the 3-month follow-up. Conclusion: Endovascular revascularization constitutes a safe and feasible treatment modality to restore erectile function in patients with arteriogenic ED and ineffective conservative management. Early elastic recoil is very frequent subsequent to balloon dilation of small-caliber erection-related arteries. Thus, mechanical scaffolding with DES is required in a high subset of ED patients to provide favorable early angiographic and clinical results.