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Simple Summary: Patent ductus arteriosus is a common congenital heart defect affecting various species, including dogs and humans. It can cause congestive heart failure and death if left-to-right shunting is substantial. In humans, assessment of the hemodynamic relevance of a patent ductus arteriosus includes evaluation of the post-ductal aortic flow pattern. We found that ultrasonographic assessment of abdominal aortic flow was feasible in dogs with a patent ductus arteriosus. However, in dogs with higher heart rates, assessment of end-diastolic flow was not always possible. A retrograde end-diastolic flow was the most accurate parameter for identifying dogs with a hemodynamically significant patent ductus arteriosus. In this multicenter, prospective, observational study, abdominal aortic flow was examined with pulsed-wave Doppler ultrasound in dogs with a left-to-right shunting patent ductus arteriosus (PDA) and in apparently healthy dogs. Forty-eight dogs with a PDA and 35 controls were included. In the dogs with a PDA, 37/48 had hemodynamically significant PDAs (hsPDAs) while 11/48 had non-hsPDAs, based on the presence or absence of echocardiographic signs of left-sided volume overload, respectively. In 12 dogs (4/35 control dogs, 7/37 dogs with an hsPDA and 1/11 dogs with a non-hsPDA), the diastole was too short to visualize the end-diastolic flow. Antegrade end-diastolic flow was observed in 30/35 controls and 6/11 dogs with a non-hsPDA. Absent end-diastolic flow was observed in 1/35 control dogs and 3/11 dogs with a non-hsPDA. Retrograde end-diastolic flow was observed in 30/37 dogs with an hsPDA and 1/11 dogs with a non-hsPDA. Twenty-one dogs (15 with an hsPDA and 6 with a non-hsPDA) were reassessed after PDA closure, and, in 19/21, end-diastolic flow was visualized: 17/19 showed an antegrade flow, 1/19 an absent flow and 1/19 a retrograde flow. Sensitivity and specificity of retrograde end-diastolic flow for detection of hsPDAs were 100% and 90%, respectively. In conclusion, ultrasonographic assessment of abdominal aortic flow was feasible in dogs with PDA. However, end-diastolic flow was not always visualized. The presence of a retrograde end-diastolic flow was an accurate finding for discriminating hsPDAs and non-hsPDAs. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to design and evaluate a deep learning-based method to automatically predict the time-varying in-plane blood flow velocity within the cardiac cavities in long-axis cine MRI, validated against 4D flow. Methods: A convolutional neural network (CNN) was implemented, taking cine MRI as the input and the in-plane velocity derived from the 4D flow acquisition as the ground truth. The method was evaluated using velocity vector end-point error (EPE) and angle error. Additionally, the E/A ratio and diastolic function classification derived from the predicted velocities were compared to those derived from 4D flow. Results: For intra-cardiac pixels with a velocity > 5 cm/s, our method achieved an EPE of 8.65 cm/s and angle error of 41.27°. For pixels with a velocity > 25 cm/s, the angle error significantly degraded to 19.26°. Although the averaged blood flow velocity prediction was under-estimated by 26.69%, the high correlation (PCC = 0.95) of global time-varying velocity and the visual evaluation demonstrate a good agreement between our prediction and 4D flow data. The E/A ratio was derived with minimal bias, but with considerable mean absolute error of 0.39 and wide limits of agreement. The diastolic function classification showed a high accuracy of 86.9%. Conclusion: Using a deep learning-based algorithm, intra-cardiac blood flow velocities can be predicted from long-axis cine MRI with high correlation with 4D flow derived velocities. Visualization of the derived velocities provides adjunct functional information and may potentially be used to derive the E/A ratio from conventional CMR exams. [ABSTRACT FROM AUTHOR]

This study aimed to derive a novel classification of blood flow pattern in abdominal aortic aneurysms (AAA) based on computational fluid dynamics (CFDs), and to determine the predictive value of flow patterns in AAA rupture. This was an age and sex matched case control study. Cases were identified as patients who underwent emergency endovascular or open repair due to ruptured or AAA at risk of impending rupture. Controls were age and sex matched with patients with an AAA who were asymptomatic and had a confirmed unruptured AAA from computed tomography angiography images from the same period. Classification of blood flow pattern (type I: non-helical main flow channel with multiple vortices; type II: non-helical main flow channel with single vortices; and type III, helical main flow channel with helical vortices) and haemodynamic parameters (areas of low wall shear stress [A lowWSS ], aneurysm pressure drop [Δ pressure], etc) were derived from CFD analyses. Multivariable regression was used to determine independent AAA rupture risk factors. The incremental discriminant and reclassification abilities for AAA rupture were compared among different models. Fifty-three ruptured and 53 intact AAA patients were included. Ruptured AAA showed a higher prevalence of type III flow pattern than intact AAA (60.4% vs. 15.1%; p <.001). Type III flow pattern was associated with a significantly increased risk of aneurysm rupture (odds ratio 10.22, 95% confidence interval 3.43 – 30.49). Among all predicting models, the combination of AAA diameter, haemodynamic parameters (A lowWSS or Δ pressure), and flow pattern showed highest discriminant abilities in both the overall population (c-index = 0.862) and subgroup patients with AAAs < 55 mm (c-index = 0.972). Compared with AAA diameter, adding the flow pattern could significantly improve the reclassification abilities in both the overall population (net reclassification index [NRI] = 0.321; p <.001) and the subgroup of AAAs < 55 mm (NRI = 0.732; p <.001). Type III flow pattern was associated with a significantly increased risk of AAA rupture. The integration of blood flow pattern may improve the identification of high risk aneurysms in both overall population and in those with AAAs < 55 mm. [ABSTRACT FROM AUTHOR]

This study hypothesizes that melatonin with exogenous progesterone (CIDR) can improve follicular, luteal, ovarian and uterine haemodynamic of heat‐stressed cows. Holstein cows (N = 12) studied for two spontaneous oestrous cycles during winter then divided equally during summer into the CIDR group received CIDR for 7 days and the melatonin group (Mel) received three injections of melatonin (75 mg/head) at the CIDR insertion, removal and ovulation days. Blood samples were collected to assay oestradiol (E2), progesterone (P4) and nitric oxide (NO). On day 0 (Ovulation), Mel had more small follicles (p <.05), higher ipsilateral and contralateral ovarian arteries (Ov.A.) peak systolic velocity (PSV), higher ipsilateral uterine artery (Ut.A.) PSV (p =.031) and blood flow volume (BFV), also Mel elevated contralateral Ut.A. PSV and BFV (p <.0001) but lowered contra Ut.A. pulsatility index (PI, p <.0001), E2 (p <.01) and NO (p <.0001). Mel increased the corpus luteum diameter (CL, p <.001), coloured area (p <.007) and P4 (p <.0001) on day 5 and reduced them (p <.05; p <.01) on Day 14. On day 10, Mel obtained CL diameter (p <.03) and coloured area (p <.002) of spontaneous that was higher than CIDR and decreased P4 (p <.003). Mel increased CL diameter, area and coloured area and decreased them thereafter. Mel increased the ipsilateral ovarian and uterine arteries PSV and BFV before ovulation and until day 8. Mel increased P4 and decreased NO until days 6 and 14. In conclusion, the improvement in follicular, luteal, ovarian and uterine haemodynamic and the decrease of NO production proved our hypothesis Melatonin doses higher than 75 mg/head is recommended to improve the heat‐stressed cow's fertility. [ABSTRACT FROM AUTHOR]

In this paper, a numerical estimation of wall shear stress (WSS) in a compliant Thoracic Aorta (TA) with aneurysm is modeled and the hemodynamic pattern is studied using Computational Fluid Dynamics (CFD). Thoracic Aortic Aneurysm (TAA) is an excessively localized enlargement of TA caused by weakness in the arterial wall and it can rupture the inner wall intima and continue on to the outer wall adventitia. WSS is a tangential force exerted by blood flow on the vessel wall, and its estimation is clinically very important because any change in WSS is considered as a vital cue in the onset of aneurysm. In this work, a three-dimensional (3D) model of a TAA reconstructed from computed tomography (CT) images comprising of 600 slices with 1-mm resolution from neck to hip is considered and patient-specific simulations have been carried out in compliant TA under rest and exercise conditions. The findings show that the change in wall geometry was marginal due to variation in pressure forces inside and is not the primary source for expansion of an aneurysm. It was inferred that expansion was rather due to thinning of the wall, owing to damage caused to the inner lining of the tissues, at regions of high WSS. It was found that the geometry extraction is important as any change in length causes a corresponding variation in mass flow through it. Although mass conservation is maintained irrespective of the length, it does affect the rate of flow due to shifting in the pressure boundary conditions with the length as it varies the pressure inside the system. Modeling of the geometry is very important as the change in mass flow will affect the outlet velocity and strength of vortices. Surprisingly, the split-up of flow is consistent but the geometric change in the model has no effect on WSS values and flow pattern. The results of this study provide important information such as blood flow pattern and pressure drops in the compliant TA on WSS estimations with TAA diseases. [ABSTRACT FROM AUTHOR]

Background: This study aims to assess the cerebral vessels flow in brain death patients with different causes, including focal and diffuse lesions and comparison of flows according to the underlying causes. Materials and Methods: Two groups of 15 brain-dead patients one with focal and the other with diffuse brain lesions were compared according to their cerebral blood flow pattern 48 h passed brain death certification. Results: Bilateral absence of flow in middle cerebral artery (MCA) was found in 54.5% of brain-dead patients with diffuse lesion and 50.33% of those with focal lesions. Systolic spike pattern in MCA flow was found in 46.2% of patients with focal lesion and 16.65% of patients with diffuse lesion. Diastole-systole separation pattern in MCA was seen in 16.65% of patients with the diffuse lesions. This pattern in MCA was not seen in patients with the focal lesion group. In carotid arteries, we did not find the absence of flow in any cases. Thirty percent of all patients in both groups had a normal flow pattern (36.6% of patients with focal lesions and 23.3% of patients with diffuse lesion). Patients with focal lesion had 33.3% systolic spike pattern flow and had 23.35% diastole-systole separation flow pattern. In intra-cranial vessels, systolic spike pattern was more common among patients with focal lesions than patients with diffuse lesion, however, this difference was not statistically significant (46.2% of patients with focal lesion and 16.65% of patients with diffuse lesion) (P value = 0.244-0.09). Diastole-systole separation flow was more common in patients with diffuse lesions than those with the focal lesions although this could not reach the significant level as the previous pattern (20% of patients with diffuse lesion versus no case in patients with focal lesion) (P value = 0.181). Conclusion: Absence of flow was the most common brain flow pattern in the focal and diffuse group lesions. There was no difference in flow pattern between the focal and diffuse brain lesions groups in brain-dead patients.

Background: Left ventricular assist device (LVAD) has become an alternative treatment for end-stage heart failure patients. Series type of LVAD, as a novel LVAD, has attracted more and more attention. The hemodynamic effects of series type LVAD on aortic blood pattern are considered as its important characteristics; however, the precise mechanism of it is still unclear.Methods: To clarify the hemodynamic effects of series type LVAD on aortic blood flow pattern, a comparative study on the aortic blood flow pattern and hemodynamic states were carried out numerically for two cases, including series type LVAD support and normal condition. The steady-state computational fluid dynamic (CFD) approach was employed. The blood flow streamline, blood velocity vector and distribution of wall shear stress (WSS) were calculated to evaluate the differences of hemodynamic effects between both conditions.Results: The results demonstrated that the aortic flow pattern under series type LVAD showed significant different from that of normal condition. The strength of aortic swirling flow was significantly enhanced by the series type LVAD support. Meanwhile, the rotating direction of swirling flow under LVAD support was also dominated by the rotating direction of series type LVAD. Moreover, the blood velocity and WSS under LVAD support were also significantly enhanced, compared with that under normal condition.Conclusion: The hemodynamic states, including the aortic swirling flow characteristic, was significantly dominated by LVAD support. Present investigation could provide not only a useful information on the vascular complications caused by LVAD support, but also provide a useful guide for optimal the structure of the series type LVAD. [ABSTRACT FROM AUTHOR]

Blood flow patterns in conduit arteries characterized by high levels of retrograde shear stress can be detrimental for vascular health. In this study we examined whether retrograde shear rate and endothelial function are related in healthy and formerly preeclamptic (PE) women and whether this relationship is altered by exercise training. Formerly PE women (32 ± 4 yr, n = 20) and controls (32 ± 4 yr, n = 20), all 6-12 mo postpartum, performed 12-wk aerobic exercise training. We measured brachial artery shear rate (SR) and endothelial function by flow-mediated dilation (FMD, echo-Doppler). We additionally performed power spectral analysis of heart rate variability and calculated low-frequency/high-frequency (LF/HF) ratio. Antegrade SR was not different between groups, while retrograde SR was significantly higher and FMD% lower in PE women compared with controls (both P < 0.05). Retrograde shear correlated strongly with FMD% in PE women and controls (P < 0.05). LF/HF ratio inversely correlated with brachial artery retrograde SR and FMD% (both P < 0.05) in PE women and controls. Exercise training reduced retrograde shear, improved FMD%, and reduced LF/HF ratios similarly in both groups (all P < 0.05). Training-induced changes in retrograde SR correlated with changes in FMD% and LF/HF ratio. A higher brachial artery retrograde SR relates to lower brachial artery endothelial function, in both controls and formerly PE women. Exercise training improves retrograde SR, while the magnitude of this change correlated strongly with improvements in FMD and reductions in LF/HF ratio. Therefore, the impact of PE and exercise training on endothelial health may, at least partly, be related to retrograde shear rate. [ABSTRACT FROM AUTHOR]

Background: This study aims to assess the cerebral vessels flow in brain death patients with different causes, including focal and diffuse lesions and comparison of flows according to the underlying causes. Materials and Methods: Two groups of 15 brain‑dead patients one with focal and the other with diffuse brain lesions were compared according to their cerebral blood flow pattern 48 h passed brain death certification. Results: Bilateral absence of flow in middle cerebral artery (MCA) was found in 54.5% of brain‑dead patients with diffuse lesion and 50.33% of those with focal lesions. Systolic spike pattern in MCA flow was found in 46.2% of patients with focal lesion and 16.65% of patients with diffuse lesion. Diastole–systole separation pattern in MCA was seen in 16.65% of patients with the diffuse lesions. This pattern in MCA was not seen in patients with the focal lesion group. In carotid arteries, we did not find the absence of flow in any cases. Thirty percent of all patients in both groups had a normal flow pattern (36.6% of patients with focal lesions and 23.3% of patients with diffuse lesion). Patients with focal lesion had 33.3% systolic spike pattern flow and had 23.35% diastole–systole separation flow pattern. In intra‑cranial vessels, systolic spike pattern was more common among patients with focal lesions than patients with diffuse lesion, however, this difference was not statistically significant (46.2% of patients with focal lesion and 16.65% of patients with diffuse lesion) (P value = 0.244‑0.09). Diastole–systole separation flow was more common in patients with diffuse lesions than those with the focal lesions although this could not reach the significant level as the previous pattern (20% of patients with diffuse lesion versus no case in patients with focal lesion) (P value = 0.181). Conclusion: Absence of flow was the most common brain flow pattern in the focal and diffuse group lesions. There was no difference in flow pattern between the focal and diffuse brain lesions groups in brain‑dead patients. [ABSTRACT FROM AUTHOR]

The article presents a study that examines the impact of various types and intensities of lower limb exercise on the brachial artery (BA) flow pattern. The study involved 12 active volunteers who performed cycling, leg kicking, and walking exercise. It cites that BA diameter, blood flow, and shear rate of the subjects were assessed at baseline and at three incremental intensity levels of the exercise. The study used edge detection and wall tracking of high-resolution B-mode arterial ultrasound images, combined with synchronized Doppler waveform envelope analysis in obtaining data. Discussion on the findings of the study is also offered.

To investigate the correlations of vascular endothelial growth factor (VEGF)-positive tumor angiogenesis and the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma. 30 patients with VEGF-positive bronchogenic adenocarcinomas (diameter ≤ 4 cm) underwent multi-location dynamic contrast material-enhanced (nonionic contrast material was administrated via the antecubital vein at a rate of 4 mL/sec by using an autoinjector) serial CT. The quantifiable parameters (Perfusion, peak height, ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta and mean transit time) of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma were compared with microvessel densities (MVDs) and VEGF expression by immunohistochemistry. Peak height of VEGF-positive bronchogenic adenocarcinoma was 36.06 HU ± 13.57 HU, bronchogenic adenocarcinoma-to-aorta ratio 14.25% ± 4.92, and perfusion value 29.66 ± 5.60 mL/min/100 g, mean transit time 14.86 s ± 5.84 s, and MVD 70.15 ± 20.03. Each of peak height, ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta and perfusion correlated positively with MVD ( r = 0.781, P < 0.0001; r = 0.688, P < 0.0001; r = 0.716, P < 0.0001; respectively). No significant correlation was found between mean transit time and MVD ( r = 0.260, P = 0.200 > 0.05). Perfusion, peak height and ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta reflect MVD in VEGF-positive bronchogenic adenocarcinoma. Perfusion, peak height and ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta derived with dynamic CT might be index for VEGF-related tumor angiogenesis in bronchogenic adenocarcinoma. [ABSTRACT FROM AUTHOR]

To evaluate the correlation of the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma (SBA). 46 patients with solitary bronchogenic adenocarcinomas (SBA) (diameter ≤ 4 cm) underwent multi-location dynamic contrast material-enhanced (nonionic contrast material was administrated via the antecubital vein at a rate of 4 mL/s by using an autoinjector 90 mL, 4 × 5 mm or 4 × 2.5 mm scanning mode with stable table were performed) serial CT. Precontrast and postcontrast attenuation on every scan was recorded. Perfusion (PBA), peak height (PHBA), ratio of peak height of the SPN to that of the aorta (BA-to-A ratio) and mean transit time (MTT) were calculated. The correlation between peak height of the aorta (PHA) and parameters of the SBA (PHBA, BA-to-A ratio, PBA, and MTT) and those among parameters of the SBA were assessed by means of linear regression analysis. Regression equation among parameters of the SBA were obtain by means of stepwise regression. The correlation between the SBA peak height (PHBA, 36.78 HU ± 12.02) and the aortic peak height (PHA) was significant ( r = 0.506, P < 0.0001). No significant correlation was found between the BA-to-A peak height ratio (15.33% ± 4.55) and the aortic peak height ( r = 0.130, P = 0.388 > 0.05) as it was between the SBA perfusion (PBA, 31.86 mL/min/100 g ± 9.74) and the aortic peak height ( r = 0.049, P = 0.749 > 0.05). The SBA perfusion correlated with the PHBA and the BA-to-A peak height ratio ( r = 0.394, P = 0.007 < 0.05; r = 0.407, P = 0.005 < 0.05). The PHBA correlated positively with the BA-to-A peak height ratio ( r = 0.781, P < 0.0001). Mean transit time was 14.84 s ± 5.52. PBA = 18.500 + 0.872 × BA-to-A ratio. BA-to-A ratio = 4.467 + 0.295 × PHBA. The linear correlation between the SBA perfusion and BA-to-A ratio and that between BA-to-A ratio and PHBA can be expressed by equation. It is possible to design a simpler scanning procedure of investigation of bronchogenic adenocarcinoma angiogenesis. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the correlation between the quantifiable parameters of blood flow pattern derived with dynamic CT in malignant solitary pulmonary nodules and tumor size. Methods: Sixty-eight patients with malignant solitary pulmonary nodules (SPNs) (diameter ≤4 cm) underwent multi-location dynamic contrast material-enhanced (nonionic contrast material was administrated via the antecubital vein at a rate of 4mL/s by using an autoinjector, 4x5 mm or 4x2.5 mm scanning mode with stable table were performed). Precontrast and postcontrast attenuation on every scan was recorded. Blood flow (BF), peak, height (PHSPN), ratio of peak height of the SPN to that of the aorta (SPN-to-A ratio) and mean transit time (MTT) were calculated. The correlation between the quantifiable parameters of blood flow pattern derived with dynamic CT in malignant solitary pulmonary nodules and tumor size were assessed by means of linear regression analysis. Results: No significant correlations were found between the tumor size and each of the peak height (PHSPN) (35.79±10.76 Hu), ratio of peak height of the SPN to that of the aorta (SPN-to-A ratio), (14.27%±4.37) and blood flow (BF) (30.18 mL/min/100 g±9.58) (r=0.180, P=0.142>0.05; r=0.205, P=0.093>0.05; r=0.008, P=0.947>0.05). Conclusion: No significant correlations were found between the tumor size and each of the quantifiable parameters of blood flow pattern derived with dynamic CT in malignant solitary pulmonary nodules. [ABSTRACT FROM AUTHOR]

Abstract: Local arterial haemodynamics has been associated with the pathophysiology of several cardiovascular diseases. The stable spiral blood-flows that were observed in vivo in several vessels, may play a dual role in vascular haemodynamics, beneficial since it induces stability, reducing turbulence in the arterial tree, and accounts for normal organ perfusion, but detrimental in view of the imparted tangential velocities that are involved in plaque formation and development. Being a spiral flow considered representative of the local blood dynamics in certain vessels, a method is proposed to quantify the spiral structure of blood flow. The proposed function, computed along a cluster of particle trajectories, has been tested for the quantitative determination of the spiral blood flow in a three-dimensional, s-shaped femoral artery numerical model in which three degrees of stenosis were simulated in a site prone to atherosclerotic development. Our results confirm the efficacy of the Lagrangian analysis as a tool for vascular blood dynamics investigation. The proposed method quantified spiral motion, and revealed the progression in the degree of stenosis, in the presented case study. In the future, it could be used as a synthetic tool to approach specific clinical complications. [Copyright &y& Elsevier]