Coronary computed tomography angiography study on the relationship between the Ramus Intermedius and Atherosclerosis in the bifurcation of the left main coronary artery.

OBJECTIVE: This study aimed to explore the relationship between the ramus intermedius (RI) and atherosclerosis in the bifurcation of the left coronary artery (LCA). METHODS: Screening patients who underwent CCTA from January to September 2021, 100 patients with RI (RI group) and 100 patients without RI (no-RI group) were randomly enrolled, Evaluation of RI distribution characteristics and left main coronary artery(LM),Left anterior descending branch(LAD),left circumflex branch(LCX) proximal segment plaque distribution, measurement of LAD-LCX bifurcation angle(∠LAD-LCX),Comparison of the three distribution characteristics with the incidence of plaques in the left main trunk bifurcation area (LM, LAD, LCX) between groups and within the RI group. RESULTS: The difference in the incidence of plaques in the proximal LCX and the LM between the RI group and the no-RI group were not statistically significant (P > 0.05). The incidence of plaques in the proximal LAD in the RI group was significantly higher than that in the non-RI group (77% versus 53%, P < 0.05). However, there was no statistically significant difference between the two groups after PSM. A univariate logistic regression analysis revealed that an RI was a risk factor for plaque formation in the proximal LAD (P < 0.001), and a multivariate logistic regression analysis revealed that an RI was not an independent risk factor for plaque formation in the proximal LAD (P > 0.05). When compared within the RI group, the difference in the incidence of plaques in the proximal segment of LAD, the proximal segment of LCX, and the LM among the different distribution groups of RI was not statistically significant, respectively (P > 0.05). CONCLUSION: RI is not an independent risk factor for atherosclerosis in the left coronary artery bifurcation zone, but it may indirectly increase the risk of atherosclerosis in the proximal segment of the LAD.

Basilar artery bifurcation anatomy as a determinant of recanalization and stroke outcome: Basilar artery bifurcation anatomy and stroke outcome.

OBJECTIVES: Thrombectomy improves outcomes in patients with basilar artery (BA) occlusion. We hypothesized that the anatomic configuration of the BA bifurcation, classified as T- or Y-shaped, may impact the outcome as a T-shaped BA would involve more deep penetrating arteries of the midbrain and thalamus. MATERIALS AND METHODS: In this 2-center retrospective cohort study, we included patients with stroke due to distal BA occlusion and performed blinded classification of their BA distal bifurcation as either T- or Y-shaped. The primary outcomes were favorable outcome at 90-days (modified Rankin Scale 0 - 2) and successful recanalization (TICI scores 2B or 3). RESULTS: 70 patients (mean age 66 years, 36% women) were included. 38 had T- and 32 had Y-shaped bifurcations. Baseline characteristics were similar for both groups, including demographics, onset to arterial puncture time, baseline NIHSS, THRIVE score, posterior circulation collateral score, and presence of tandem occlusion. Comparing the T- to the Y- shape, there was no difference in the likelihood of successful recanalization (RR: 1.02, CI: [0.86-1.21], p=1.00) nor 90-day favorable mRS (0-2) score (RR: 0.58, CI: [0.25-1.32]; p=0.18). Similarly, mortality at 30 and 90-days were not significantly affected by the type of bifurcation. CONCLUSIONS: The configuration of the basilar artery does not significantly impact on recanalization success or stroke outcome in our study. Further studies are needed to confirm our observations.

Angiographic predictors of aberrant circumflex artery during cardiac catheterization.

OBJECTIVES: To identify angiographic predictors of aberrant left circumflex artery (LCx) by comparing left main (LM) length and bifurcation angle between patients with aberrant LCx and normal anatomy. BACKGROUND: Failure to recognize aberrant LCx during a cardiac catheterization may hamper correct diagnosis, delay intervention in acute coronary syndromes, and result in increased contrast volume, radiation exposure, and infarct size. METHODS: We retrospectively analyzed angiograms of aberrant LCx patients and normal anatomy matched controls, in three-participating centers. LM-length, bifurcation angle between the left anterior descending (LAD) and the first non-LAD branch of the LM, and procedural data were compared. RESULTS: Between 2003 and 2020, 136 patients with aberrant LCx and 135 controls were identified. More catheters (2.4 ± 0.6 vs. 2.2 ± 0.9, p = 0.009), larger contrast volumes (169 ± 94 ml vs. 129 ± 68 ml, p < 0.0005), and prolonged fluoroscopy time (652.9 ± 623.7 s vs. 393.1 ± 332.1 s, p < 0.0005), were required in the aberrant LCx-group compared with controls. Patients with aberrant LCx had a longer LM-length and a more acute bifurcation angle, both in caudal and cranial views, compared with controls (24.7 ± 8.1 vs. 10.8 ± 4.5 mm, p < 0.0005 and 26.7 ± 7.4 vs. 12 ± 5.5 mm, p < 0.0005, respectively, and 45.2° ± 12° vs. 88.8° ± 23°, p < 0.0005 and 51.9° ± 21° vs. 68.2° ± 28.3°, p < 0.0005, respectively). In ROC analysis, LM-length showed the best diagnostic accuracy for detecting aberrant LCx. In multiple logistic regression analysis, a cranially measured LM-length > 17.7 mm was associated with a 5.3 times greater probability of predicting aberrant LCx [95% CI (3.4-8.1), p < 0.0001]. CONCLUSIONS: Our study suggests that a long LM-length and an acute bifurcation angle can indicate the presence of aberrant LCx. We present a practical algorithm for its rapid identification.

Paradoxical changes of coronary computed tomography derived fractional flow reserve.

A total of 1335 outpatients with suspected coronary artery disease and who underwent computed tomography derived fractional flow reserve (FFRCT ) analysis were examined. Only four patients showed reverse increase of FFRCT from the proximal to the distal vessel and all of them had a large ramus artery (RAM). Of all parameters (vessel length, lumen volume, plaque volume, and left ventricular mass), only the bifurcation angle was significantly higher in reverse increase of FFRCT with RAM group (106.0 ± 15.8°) than normal FFRCT with RAM group (82.6 ± 21.7°) and normal FFRCT without RAM group (66.9 ± 21.1°).

Middle cerebral arterial bifurcation aneurysms are associated with bifurcation angle and high tortuosity.

PURPOSE: To investigate the association of middle cerebral artery (MCA) bifurcation aneurysms with bifurcation morphology. MATERIALS AND METHODS: 205 patients were enrolled, including 61 patients with MCA bifurcation aneurysms and 144 non-aneurysmal subjects. Aneurysmal cases were divided into types C (aneurysm neck on extension of the parent artery centerline) and D (deviating neck). The radius of the parent artery M1 (RP) and bilateral branches (RS and RL, respectively), smaller (φS) and larger (φL) lateral angles, bifurcation angle, and arterial tortuosity from parent vessel to bilateral branches (TS and TL, respectively) were analyzed. Logistic regression and receiver operator characteristic (ROC) curve analysis were performed to identify risk factors and predictive values for MCA aneurysm presence and types. RESULTS: In aneurysmal MCA bifurcations, bifurcating angle, TS, TL and RL were significantly larger (P<0.01), while φS was significantly smaller (P<0.001) than those in controls. The bifurcation angle, TS and LogitP were better morphological parameters for predicting MCA aneurysm presence with the AUC of 0.795, 0.932 and 0.951, respectively. Significant (P<0.05) differences were observed in the bifurcation angle, φL, RP, RL and TL between types C and D aneurysmal bifurcations. TL was an independent factor in discriminating types C from D aneurysms with an AUC of 0.802. CONCLUSIONS: Bifurcation angle and arterial tortuosity from the parent artery to the branch forming a smaller angle with the parent artery have a higher value in distinguishing MCA aneurysmal from non-aneurysmal ones, and the tortuosity from the parent artery to the contralateral branch is the best indicator for distinguishing types C from D aneurysmal bifurcations.

Image-guided simulation in comparison with laser speckle contrast imaging for full-field observation of blood flow in a microvasculature model.

The in vitro reconstruction of the microvascular network model provides a reproducible platform for hemodynamic study with great biological relevance. In the present study, microvascular models with different parametric features were designed under the guidance of Murray's law and derived from representative natural vascular network topography in vivo. Computational fluid dynamics (CFD) was used to numerically simulate blood velocity distributions inside of the designed microvasculature models. Full-field blood flow in the vascular network was visualized in vivo using a laser speckle contrast imaging (LSCI) system, from which the measured relative velocity was compared with CFD computed flow distribution. The results have shown that, in comparison with the simplified flow patterns obtained from idealized geometries, the irregular vascular topography is expected to lead to nonuniform and poor regional blood velocity distribution. The velocity distribution acquired by in vivo LSCI experiment is in good agreement with that of numerical simulation, indicating the technical feasibility of using biomimetic microchannels as a reasonable approximation of the microcirculatory flow conditions. This study provides a new paradigm that can be well suited to the study of microvascular blood flow properties and can further expand to mimic other in-vivo scenarios for accurately recapitulating the physical and hemodynamic environment of the microcirculation.

Quantitative CT-based structural alterations of segmental airways in cement dust-exposed subjects.

BACKGROUND: Dust exposure has been reported as a risk factor of pulmonary disease, leading to alterations of segmental airways and parenchymal lungs. This study aims to investigate alterations of quantitative computed tomography (QCT)-based airway structural and functional metrics due to cement-dust exposure. METHODS: To reduce confounding factors, subjects with normal spirometry without fibrosis, asthma and pneumonia histories were only selected, and a propensity score matching was applied to match age, sex, height, smoking status, and pack-years. Thus, from a larger data set (N = 609), only 41 cement dust-exposed subjects were compared with 164 non-cement dust-exposed subjects. QCT imaging metrics of airway hydraulic diameter (Dh), wall thickness (WT), and bifurcation angle (θ) were extracted at total lung capacity (TLC) and functional residual capacity (FRC), along with their deformation ratios between TLC and FRC. RESULTS: In TLC scan, dust-exposed subjects showed a decrease of Dh (airway narrowing) especially at lower-lobes (p < 0.05), an increase of WT (wall thickening) at all segmental airways (p < 0.05), and an alteration of θ at most of the central airways (p < 0.001) compared with non-dust-exposed subjects. Furthermore, dust-exposed subjects had smaller deformation ratios of WT at the segmental airways (p < 0.05) and θ at the right main bronchi and left main bronchi (p < 0.01), indicating airway stiffness. CONCLUSIONS: Dust-exposed subjects with normal spirometry demonstrated airway narrowing at lower-lobes, wall thickening at all segmental airways, a different bifurcation angle at central airways, and a loss of airway wall elasticity at lower-lobes. The airway structural alterations may indicate different airway pathophysiology due to cement dusts.

In vitro flow and optical coherence tomography comparison of two bailout techniques after failed provisional stenting for bifurcation percutaneous coronary interventions.

OBJECTIVES: To evaluate, in vitro, SB stenting techniques after failed provisional stenting. We aimed to compare flows and stent strut apposition of T and protrusion (TAP) versus Reversed String (RS) techniques using a flow simulator, optical coherence tomography (OCT) using silicon bifurcation phantoms with different bifurcation angulations. BACKGROUND: While bifurcation coronary artery stenoses are preferably treated with provisional T-stenting strategy, the preferred bailout two stents technique to treat the side branch remains unclear. METHODS AND RESULTS: Eleven 30°-angle and ten 60°-angle bifurcation phantoms were used. After performing provisional stenting, TAP and RS techniques were compared in six phantoms with 30° and five with 60° angles. Flow measurement was performed using absolute coronary flow and particle image velocimetry techniques. Strut apposition was evaluated using OCT. Flow analyses showed that disturbed flow regions were observed in the vicinity of floating struts protruded into the lumen both regardless of TAP and RS techniques. OCT analysis showed a higher proportion of floating struts protruding into the main branch with TAP compared to RS, respectively (13% vs. 1%; P <0.001) in both angles. CONCLUSIONS: RS reduces the proportion of floating struts protruding into the main branch compared to TAP, at comparable flow rates. Clinical studies are needed to evaluate feasibility and potential clinical benefit of this technique.

Predicting bifurcation angle effect on blood flow in the microvasculature.

Since blood viscosity is a basic parameter for understanding hemodynamics in human physiology, great amount of research has been done in order to accurately predict this highly non-Newtonian flow property. However, previous works lacked in consideration of hemodynamic changes induced by heterogeneous vessel networks. In this paper, the effect of bifurcation on hemodynamics in a microvasculature is quantitatively predicted. The flow resistance in a single bifurcation microvessel was calculated by combining a new simple mathematical model with 3-dimensional flow simulation for varying bifurcation angles under physiological flow conditions. Interestingly, the results indicate that flow resistance induced by vessel bifurcation holds a constant value of approximately 0.44 over the whole single bifurcation model below diameter of 60µm regardless of geometric parameters including bifurcation angle. Flow solutions computed from this new model showed substantial decrement in flow velocity relative to other mathematical models, which do not include vessel bifurcation effects, while pressure remained the same. Furthermore, when applying the bifurcation angle effect to the entire microvascular network, the simulation results gave better agreements with recent in vivo experimental measurements. This finding suggests a new paradigm in microvascular blood flow properties, that vessel bifurcation itself, regardless of its angle, holds considerable influence on blood viscosity, and this phenomenon will help to develop new predictive tools in microvascular research.

How bifurcation angle impacts the fate of side branch after main vessel stenting: a retrospective analysis of 1,200 consecutive bifurcation lesions in a single center.

OBJECTIVES: We aimed to investigate the effect of bifurcation angle (BA) on side branch (SB) occlusion after main vessel (MV) stenting. BACKGROUND: BA is thought to impact the risk of SB occlusion in coronary bifurcation patients undergoing percutaneous coronary intervention (PCI). METHODS: A total of 1,171 consecutive patients with 1,200 bifurcation lesions undergoing one stent or provisional two stent techniques were studied. The lesions were divided into low angle and high angle groups using the median BA (52°). Multivariate logistic regression analysis was performed to identify independent predictors of SB occlusion. RESULTS: SB occlusion occurred in 88 (7.33%) of 1,200 bifurcation lesions treated with the one stent technique or MV stenting first strategy. The rate of SB occlusion was significantly higher in the high angle group (63/600, 10.5%) than the low angle group (25/600, 4.2%) (P < 0.001). The rate of SB occlusion increased significantly across quartiles of BA as follows: from 3.63% in the first quartile of BA, to 4.71% in quartile II, to 8.14% in quartile III to 12.97% in quartile IV (P < 0.001). Multivariable analysis showed that high angle was an independent predictor of SB occlusion (odds ratio: 1.026, 95% confidence intervals: 1.014-1.037, P < 0.001). Plaque distribution at the same side of SB, MV Thrombolysis in Myocardial Infarction flow grade before stenting, pre-procedural diameter stenosis of bifurcation core, diameter ratio between MV/SB and diameter stenosis of SB before MV stenting were also independent predictors of SB occlusion. CONCLUSIONS: High BA was an independent predictor of SB occlusion after MV stenting. The occlusion risk of SB with a high BA should not be ignored.

Left anterior descending coronary artery-left circumflex coronary artery bifurcation angle and severity of coronary artery disease; is there any correlation? A cross-sectional study.

Background and Aims: The aim of this study is to evaluate the association of coronary computed tomography angiography derived (CCTA) plaque characteristics and the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCX) bifurcation angle with severity of coronary artery disease (CAD). Methods: All the stable patients with suspected CAD who underwent CCTA between January to December 2021 were included. Correlation between CCTA-derived aggregated plaque volume (APV), LAD-LCX angle, remodeling index (RI), coronary calcium score with Gensini score in conventional angiography were assessed. One hundred and twenty-two patients who underwent both CCTA and coronary angiography were analyzed. Results: Our analysis showed that the median (percentile 25% to percentile 75%) of the APV, LAD-LCx angle, and calcium score were 31% (17%-47%), 58° (39°-89°), and 31 (0-186), respectively. Also, the mean ± SD of the RI was 1.05 ± 0.20. Significant correlation between LAD-LCx bifurcation angle (0.0001-0.684), APV (0.002-0.281), RI (0.0001-0.438), and calcium score (0.016-0.217) with Gensini score were detected. There was a linear correlation between the mean LAD-LCx bifurcation angle and the Gensini score. The sensitivity and specificity for the cut-off value of 47.5° for the LAD-LCX angle were 86.7% and 82.1%, respectively. Conclusion: There is a direct correlation between the LAD-LCx angle and the Gensini score. In addition to plaque characteristics, anatomic-based CCTA-derived indices can be used to identify patients at higher risk for CAD.

Association between Carotid Bifurcation Angle and Vulnerable Plaque Volume Using Black Blood Magnetic Resonance Imaging.

The morphology of the internal carotid artery (ICA) bifurcation is increasingly being recognized as the cause of atherosclerosis and vulnerable plaque leading to cerebral infarction. In this study, we investigated the relationship between carotid bifurcation angle and carotid plaque volume evaluated using black blood magnetic resonance imaging (BB-MRI). Among the 90 patients who underwent revascularization for atherosclerotic symptomatic carotid stenosis between April 2016 and October 2022 using BB-MRI, carotid plaque was evaluated in 57 patients. Relative overall signal intensity (roSI) was defined as the signal intensity of the plaque on T1-weighted images relative to the signal intensity of the sternocleidomastoid muscle in the same slice as the common carotid bifurcation. Regions showing roSI ≥ 1.0 were defined as plaque, and the plaque volume and relative plaque volume were measured from roSI ≥1.0 to ≥2.0 in 0.1 increments. We calculated the angles between the common carotid artery (CCA) and the ICA and between the CCA and the external carotid artery (ECA) on magnetic resonance angiography. We classified two groups according to carotid bifurcation angles based on the ICA angle: Group A = <35° and Group B = ≥35°. Compared with Group A (n = 42), Group B (n = 15) showed a greater relative plaque volume between roSI ≥ 1.3 and roSI ≥ 1.5. A significant correlation was identified between relative plaque volume with roSI ≥ 1.4 and ICA angle (p = 0.049). Vulnerable plaque was significantly more frequent in the group with an ICA angle of ≥35. Moreover, the ICA angle was significantly greater in patients with a roSI of ≥1.4.

A coronary computed tomography angiography study on anatomical characteristics of the diagonal branch of anterior interventricular artery.

BACKGROUND: This study investigated the anatomical characteristics of the ramus intermedius (RI) and its correlation with the proximal diameter of the branch vessels of the left coronary artery (LCA) using coronary computed tomography angiography (CCTA). MATERIALS AND METHODS: We screened patients who underwent CCTA from January to September 2021 and randomly enrolled 267 with RI (RI group) and 134 without RI (control group). We evaluated the anatomical features of RI (distribution, proximal diameter, length). We measured the proximal diameter of the anterior interventricular branch of the left coronary artery (LAD) and the circumflex branch of the left coronary artery (LCX). We compared the differences between groups in the proximal diameter of LAD and LCX and the correlation between gender and each parameter of the LCA (LAD, LCX, RI) within the RI group. In addition, we compared the correlation between the distribution characteristics of RI and the proximal diameter of LAD and LCX within the RI group. RESULTS: The LAD and LCX proximal diameters in the RI group were significantly smaller than those in the control group (p < 0.05). Comparisons within the RI group showed the following results: the RI distribution, RI diameter and length, and the LCX proximal diameter were not significantly different between male and female patients (p > 0.05), and the LAD proximal diameter was significantly larger in male than in female patients (p < 0.05). There were statistically significant differences in the LAD and LCX proximal diameters between the different RI distribution groups (p < 0.05). Based on the pairwise comparison, there were significant differences in the LAD (LCX) proximal diameter between the RI-beside- -the-LAD (LCX) group and the RI-middle group, as well as between the RI-beside- -the-LAD (LCX) group and the RI-beside-the-LCX (LAD) group (p < 0.05). CONCLUSIONS: A CCTA accurately evaluated the anatomical characteristics of an RI, which has an impact on the proximal diameter of the branch vessels of the LCA (i.e. LAD and LCX), the degree of influence of which is correlated with the RI distribution.

Association between bifurcation angle of the left main coronary artery and severity of stenosis of the proximal left anterior descending artery.

AIM: The aim of this study was to evaluate the association between the left main coronary artery (LM) bifurcation angle and the severity of the proximal left anterior descending coronary artery (LAD) stenosis. METHODS: Two hundred patients with suspected coronary artery disease who had coronary angiography were included in this observational study. The severity of coronary artery stenosis was analysed using quantitative coronary angiography software (QCA analysis). The LM-LAD and LAD-left circumflex artery (LCX) angles were measured using software (IC MEASURE) in two-dimensional axial images. RESULTS: The patients were divided into two groups. The first group included 100 patients with significant proximal LAD stenosis (≥ 50%) and the second, those with LAD stenosis < 50% (100 patients). Patients with significant proximal LAD stenosis were older and had a higher frequency of diabetes mellitus, and higher serum creatinine and low-density lipoprotein levels than those with non-significant LAD stenosis. The LM-LAD and LAD-LCX angles in patients with significant proximal LAD stenosis were wider than in patients with non-significant LAD stenosis (p < 0.001). The cut-off value of 42° of the LM-LAD angle had a sensitivity of 73% and specificity of 70% to predict significant proximal LAD stenosis. The cut-off value of 68° of the LAD-LCX angle had a sensitivity of 68% and specificity of 62% to predict significant proximal LAD disease. In a multivariate logistic regression analysis, LM-LAD and LAD-LCX angles were independent factors for the development of significant proximal LAD stenosis. CONCLUSIONS: Wider LM-LAD and LAD-LCX angles were associated with the severity of proximal LAD disease. Preventative measures and close follow up are needed in such cases to improve their cardiovascular outcome.

Dynamic assessment of the left main-left circumflex bending angle: Implications for ostial left circumflex artery in-stent restenosis after successful two-stent PCI.

BACKGROUND: Two-stent techniques for percutaneous coronary intervention (PCI) on left main (LM) bifurcation (LMB) lesions are associated with an increased risk of in-stent restenosis (ISR) at left circumflex artery (LCx) ostium but the underlying mechanisms are incompletely understood. This study sought to investigate the association between cyclic change of LM-LCx bending angle (BALM-LCx) and the risk of ostial LCx ISR following two-stent techniques. METHODS: In a retrospective cohort of patients undergoing two-stent PCI for LMB lesions, BALM-LCx and distal bifurcation angle (DBA) were computed with 3-dimensional angiographic reconstruction. The analysis was performed both at end-diastole and end-systole, and the angulation change throughout the cardiac cycle was defined as the cardiac motion-induced angulation change (∆CAngle). RESULTS: A total of 101 patients were included. The mean pre-procedural BALM-LCx was 66.8 ± 16.1° at end-diastole and 54.1 ± 13.3° at end-systole with a range of 13.0 ± 7.7°. Pre-procedural ∆CBALM-LCx > 16.4° was the most relevant predictor of ostial LCx ISR (adjusted OR 11.58, 95% CI 4.04-33.19; p < 0.001). Post-procedural ∆CBALM-LCx > 9.8° and stent-induced diastolic BALM-LCx change > 11.6° were also related with ostial LCx ISR. DBA was positively correlated with BALM-LCx and showed a weaker association of pre-procedural ∆CDBA > 14.5° with ostial LCx ISR (adjusted OR 6.87, 95% CI 2.57-18.37; p < 0.001). CONCLUSIONS: Three-dimensional angiographic bending angle is a feasible and reproducible novel method for LMB angulation measurement. A large pre-procedural cyclic change of BALM-LCx was associated with an increased risk of ostial LCx ISR following two-stent techniques.

Secondary flow in bifurcations - Important effects of curvature, bifurcation angle and stents.

Coronary bifurcations have complex flow patterns including secondary flow zones and helical flow, which directly affect pathophysiological mechanisms such as the development of atherosclerosis. The objective of this study was to generate insights into the effects of curvature, bifurcation angle and the presence of stents on flow patterns and resulting haemodynamics in coronary left main bifurcations. The blood flow and associated metrics were modelled in both idealised and patient-specific bifurcations with varying curvature and bifurcation angles with and without stents, resulting in a total of 128 geometries considered. The results showed that larger curvature of bifurcating vessels has a significant influence on secondary flow, especially with distance to the bifurcation region, causing a skew, spin and asymmetry of Dean vortices, an increase in helical flow intensity with symmetry loss, and a decrease in adversely low time-average wall shear stress (TAWSS). Generally, asymmetric flow patterns coincided with adversely low TAWSS regions. In identical stented geometries, the presence of the stents induced local recirculation immediately adjacent to the stent struts, thus generating adversely low TAWSS in these areas, with some effect on the overall secondary flow. Overall, the effect of stents outweighed the effect of curvature and BA. This new knowledge contributes to a better understanding of the joint effects of curvature, bifurcation angle, and stents on flow patterns and haemodynamics in coronary bifurcations.

Carotid angle in young stroke.

PURPOSE: To investigate whether the carotid bifurcation angle as assessed by computed tomographic angiography (CTA) is associated with anterior circulation ischemic stroke (ACIS) in young patients. MATERIAL AND METHODS: Thirty patients (mean age 41.5 ± 6 years) with known acute ACIS (group 1) were compared to 30 control patients (mean age/ 41.2 ± 6 years) (group 2) with similar demographic variables in this retrospective study. Geometrical characteristics of bilateral carotid bifurcation were obtained by CTA. The ICA bifurcation (ICAB) angle, the carotid central bifurcation (CCB), and the carotid bifurcation wall (CBW) angle among the ICA, CCA, and ECA were measured. Carotid artery angle measurements were compared between group 1 and group 2. The comparison of pathological (ACIS) and non-pathological (non-ACIS) carotid sides in group 1 was performed as well. RESULTS: All the measured angles (AMA) of group 1 were higher than group 2 (p˂0.05). In patients with left-sided ACIS, AMA on the left side were higher than the right side (p˂0.05), this was more prominent in males (p˂0.05). All angles measured were found to be higher in ipsilateral ACIS (p˂0.05). The left CCB angle values had a significant effect on ischemic stroke (p˂0.05). Male patients had more left-sided ACIS (p˂0.05). Plaque development in ICA was found statistically significant in group 1 compared to group 2 (p˂0.05). CONCLUSION: Carotid artery geometry may play an important role in the development of ischemic events in young patients, especially in men and, also in patients with left-sided stroke. The left CCB angle had a significant effect on ACIS.

Effect of asymmetry on the flow behavior in an idealized arterial bifurcation.

Flow behavior at the arterial bifurcations has significant implications on the plaque formation. It depends on the vessel size, two bifurcation angles, i.e. angle between the mother and daughter vessels and their relative magnitudes. In this study, hemodynamics for steady and pulsatile flow of blood has been investigated in an idealized carotid artery bifurcation having all the vessels in the same plane for a range of bifurcation angles for symmetric and asymmetric bifurcation. The simulations reveal the presence of a pair of helical vortices, symmetric about the bifurcation plane, in each daughter tube near the bifurcation.

Effect of Coronary Artery Bifurcation Angle on Atherosclerotic Lesion Localization Distance to the Bifurcation Site.

OBJECTIVES: Although percutaneous coronary interventions become a common treatment modality for coronary artery diseases, lesion localization make these procedures more complex. As the lesion localizes near to the bifurcation site, more complex PCI procedures, overqualified equipments are needed and complication risk increases. Previous studies have demonstrated the strong correlation between wide angulation and significant coronary stenosis. However, a paucity of data exists about the association between bifurcation angle and lesion localization distance. In this study we analysed the effect of coronary bifurcation angle and left main coronary artery length on the atherosclerotic lesion localization. METHODS: Patients, who underwent coronary angiography between 01.01.2017- 31.12.2019 were scanned. Patients having atherosclerotic lesions causing more than 50% luminal narrowing and Medina classification score (0,0,0) were evaluated. After exclusion, 467 patients were included. 5 bifurcation subgroups (LAD-CX, LAD-Dx, CX-OM, RCA-RV, RPD-RPL) were formed. Distance of lesion to the bifurcation site, bifurcation angle and left main coronary artery length were analysed by 2 experienced cardiologists with invasive quantitaive coronary angiography (QCA) by using "extreme angio and cardiac pacs" software system. RESULTS: There was a strong inverse correlation between bifurcation angle and lesion localization distance to the bifurcation site (r = -0.706; p < 0.0001). There was a nonsignificant negative correlation between Left-main coronary artery length and lesion localization. Regression analysis revealed that bifurcation angle is an independent risk factor for predicting the localization of an atheroslerotic lesion in 5 mm length from the point of bifurcation site (ß = -0.074, p < 0.0001). A cut-off value of 80.5° coronary bifurcation angle was found to have 84.1% sensitivity and 81.3% specificity in prediction of atherosclerotic lesion localization in 5 mm length from the point of bifurcation site. CONCLUSION: In this study we showed that as the bifurcation angle increases, atherosclerotic lesions tend to approach to the bifurcation site. Since invertentions encompassing bifurcation sites are more complex, lesions with increased angulation may need extra care as they are more likely to present with further complications. Furthermore, bifurcation angle is an independent risk factor for lesion localization.

Geometry of the Carotid Artery and Its Association With Pathologic Changes in a Chinese Population.

OBJECTIVES: Carotid artery geometry influences blood flow disturbances and is thus an important risk factor for carotid atherosclerosis. Extracellular matrix (ECM) and yes-associated protein (YAP) expression may play essential roles in the pathophysiology of carotid artery stenosis, but the effect of blood flow disturbances of carotid bifurcation location on the ECM is unknown. We hypothesized that carotid artery anatomy and geometry are independently associated with the ECM and YAP expression. METHODS: In this cross-sectional study, 193 patients were divided into two groups: an asymptomatic group (n = 111) and a symptomatic group (n = 82), symptomatic patients presenting with ischemic attack, amaurosis fugax, or minor non-disabling stroke. For all subjects before surgery, carotid bifurcation angle and internal artery angle were measured with computed tomography angiography (CTA), and laminar shear stress was measured with ultrasonography. After surgery, pathology of all plaque specimens was analyzed using hematoxylin and eosin (HE) staining and Movat special staining. Immunohistochemistry was performed to detect expression of YAP in a subset of 30 specimens. RESULTS: Symptomatic patients had increased carotid bifurcation angle and laminar shear stress compared to asymptomatic patients (P < 0.05), although asymptomatic patients had increased internal carotid angle compared to symptomatic patients (P < 0.001). Relative higher bifurcation angles were correlated with increased carotid bifurcation, decreased internal angle, and decreased laminar shear stress. For each change in intervertebral space or one-third of vertebral body height, carotid bifurcation angle changed 4.76°, internal carotid angle changed 6.91°, and laminar shear stress changed 0.57 dynes/cm2. Pathology showed that average fibrous cap thickness and average narrowest fibrous cap thickness were greater in asymptomatic patients than symptomatic patients (P < 0.05). Expression of proteoglycan and YAP protein in symptomatic patients was higher than in asymptomatic patients (P < 0.001), while collagen expression was lower in symptomatic patients than asymptomatic patients (P < 0.05). CONCLUSION: Geometry of the carotid artery and position relative to cervical spine might be associated with ECM and YAP protein expression, which could contribute to carotid artery stenosis.