Left Coronary Bifurcation Angle Research Articles

Impact of left coronary artery bifurcation angle on computed tomography derived fractional flow reserve in normal coronary artery disease

Abstract Funding Acknowledgements Type of funding sources: None. Background Computed-tomography (CT) derived fractional-flow-reserve (FFRCT) decreases from the proximal to the distal part of vessel due to the influence of various factors. The energy loss due to the bifurcation angle may potentially contribute to a progressive FFRCT decline. However, the association of the bifurcation angle with FFRCT is still not entirely understood. Purpose This study aimed to investigate the impact of various bifurcation angles on FFRCT decline below the clinically crucial pathological value of 0.80 in normal coronary arteries. Methods A total of 83 consecutive patients who underwent both CT angiography including FFRCT and invasive coronary angiography, resulting in normal coronary arteries were evaluated. ΔFFRCT was defined as the magnitude of the change in FFRCT from the proximal to the distal vessel in the left anterior descending (LAD) and left circumflex (LCX). Both LAD angle and LCX bifurcation angle were measured as the crossing angle between the centrelines of the left main trunk and each coronary artery (LAD or LCX) on the 3-dimensional volume rendered image of the coronary artery tree (Figure 1). Vessel length, lumen volume, non-calcified plaque volume, and calcified plaque volume were assessed. Results Bifurcation angle was significantly lower in LAD angle (LAD angle, 31.1 ± 6.6°; LCX angle, 42.8 ± 14.9°, p < 0.0001). FFRCT showed a continuous gradual decline from the proximal to the distal in both LAD (from 0.95 ± 0.03 to 0.81 ± 0.06) and LCX (from 0.96 ± 0.03 to 0.88 ± 0.06). ΔFFRCT was significantly greater in LAD angle (LAD angle, 0.13 ± 0.06; LCX angle, 0.08 ± 0.05, p < 0.0001) ΔFFRCT was significantly correlated with each bifurcation angle (LAD angle, r = 0.35, p = 0.001; LCX angle, r = 0.26, p = 0.02) and vessel length (LAD angle, r = 0.30, p = 0.005; LCX angle, r = 0.49, p < 0.0001) (Figure 2A). In LAD, vessel length was the strongest predictor for distal FFRCT of ≤ 0.80 (β-coefficient = 0.56, p = 0.0002), immediately followed by the bifurcation angle (β-coefficient = 0.24, p = 0.02). The bifurcation angle was a good predictor for a distal FFRCT ≤ 0.80 (LAD angle, cut-off 31.0°, AUC 0.70, 95% CI 0.58–0.83, sensitivity 74%, specificity 68%; LCX angle, cut-off 52.6°, AUC 0.86, 95% CI 0.76–0.96, sensitivity 88%, specificity 85%) (Figure 2B). Conclusions The change in FFRCT depended on the bifurcation angle. In normal coronary arteries, vessel length was the most influential factor on FFRCT, immediately followed by the bifurcation angle.

Evaluation of the Relationship between Left Coronary Artery Bifurcation Angle and Coronary Artery Disease: A Systematic Review.

Recent studies have suggested a relationship between wide left coronary artery bifurcation (left anterior descending [LAD]-left circumflex [LCx]) angle and coronary artery disease (CAD). Current literature is multifaceted. Different studies have analysed this relationship using computational fluid dynamics, by considering CAD risk factors, and from simple causal-comparative and correlational perspectives. Hence, the purpose of this systematic review was to critically evaluate the current literature and determine whether there is sufficient evidence available to prove the relationship between LAD-LCx angle and CAD. Five electronic databases (ProQuest, Scopus, PubMed, CINAHL Plus with Full Text, and Emcare) were used to locate relevant texts, which were then screened according to predefined eligibility criteria. Thirteen eligible articles were selected for review. Current evidence suggests individuals with a wide LAD-LCx angle experience altered haemodynamics at the bifurcation site compared to those with narrower angles, which likely facilitates a predisposition to developing CAD. However, further research is required to determine causality regarding relationships between LAD-LCx angle and CAD risk factors. Insufficient valid evidence exists to support associations between LAD-LCx angle and degree of coronary stenosis, and future haemodynamic analyses should explore more accurate coronary artery modelling, as well as CAD progression in already stenosed bifurcations.

Influence of bifurcation angle in left coronary artery with stenosis: A CFD analysis.

The left coronary artery commonly known as LCA gets divided into two branches, such as the left circumflex (LCX) and left anterior descending (LAD) at a particular angle. This angle is varies from person to person. The present computational study contributes remarkable expertise about the influence of this angle variation on the hemodynamic parameters in the presence of 80% area stenosis at the LAD branch. This study aimed to compare the effect of the bifurcation angle on hemodynamic parameters in the left coronary artery with 80% stenosis. Computational models of left coronary bifurcation angles of 30°, 60°, 90°, 120° were developed to understand the flow behavior of left coronary artery branches. The 80% area stenosis (AS) is considered at the LAD branch immediate to bifurcation. Measurements of pressure, velocity and wall shear stress were carried out corresponding to various bifurcation angles. It was found that the drop-in pressure increases as the angle increases from narrow to wider. A slight elevation in the velocity at the stenosis was observed. In addition, the obtained results further reveal a recirculation region immediately after the plaque, which leads to more deposition of plaque in the flow obstructed area. It is known that the shear stress at the arterial wall across the stenosis increases as the angle of bifurcation increases from narrow to wider. The bifurcation of the left coronary artery and size of the stenosis have a notable impact on the pressure and wall shear stress. These two factors should be given due consideration by cardiologists to assess the complexity of stenosis in the LCA branches.

Effect of left coronary bifurcation angle and left main coronary artery length on coronary artherosclerotic plaque burden

Effect of left coronary bifurcation angle and left main coronary artery length on coronary artherosclerotic plaque burden

Correlation between left main coronary artery bifurcation angle and non-calcified plaque and its hydrodynamics

Objective To investigate the correlation between the angle and distribution of non-calcified plaque of left main coronary bifurcation and its hydrodynamic theory. Methods Retrospective analysis of 55 patients suspected of coronary heart disease who had undergone coronary computed tomographic angiography from January 2014 to June 2016. Angle, quadrant distribution, distance from bifurcation reference plane, minimal lumen area and extravascular elastic membrane cross section area of left main coronary bifurcation were measured. Then we calculated the plaque burden. The left main coronary bifurcation lesions were divided into plaque group and non-plaque group. Student's t test was used to compare the two groups.The left main coronary bifurcation lesions were divided into ≥70° group and<70° group, Chi-square test and Fisher exact test were used to compared the two groups. Pearson correlation analysis was used to analyse the bifurcation angle and plaque distance. The data of non-plaque group was imported into the MIMICS,3-MATIC and abaqus CFD software to establish the hydrodynamic model, which was used to analyze the changes of pressure and velocity at different angles. Results Plaque group has 25 patients whose average value of the bifurcation angle was (55.95±14.77)°;non-plaque group has 30 patients whose average value of the bifurcation angle was(55.95±14.77)°.Angle difference was statistically significant between plaque and non-plaque group(t=2.893, P=0.006);Plaque difference was statistically significant between ≥70° and<70° groups. The distance was negatively correlated with bifurcation angle(r=-0.773, P<0.001). Following the increase of bifurcation angle, the vascular wall area of high pressure and low speed region growed The green region of low-wall pressure with irregular distribution appeared in the lateral wall of the vessel that opposite to the red region of the bifurcation, and this region had lager gradient variability of wall pressure. Conclusion With the increase of coronary bifurcation angle, the possibility of plaque formation increases, the distance from plaque to bifurcation increases,the plaques tend to appear in the lateral wall of the blood vessels. Key words: Coronary vessels; Tomography, X-ray computed; Hydrodynamic

An investigation of correlation between left coronary bifurcation angle and hemodynamic changes in coronary stenosis by coronary computed tomography angiography-derived computational fluid dynamics.

To investigate the correlation between left coronary bifurcation angle and coronary stenosis as assessed by coronary computed tomography angiography (CCTA)-generated computational fluid dynamics (CFD) analysis when compared to the CCTA analysis of coronary lumen stenosis and plaque lesion length with invasive coronary angiography (ICA) as the reference method. Thirty patients (22 males, mean age: 59±6.9 years) with calcified plaques at the left coronary artery were included in the study with all patients undergoing CCTA and ICA examinations. CFD simulation was performed to analyze hemodynamic changes to the left coronary artery models in terms of wall shear stress, wall pressure and flow velocity, with findings correlated to the coronary stenosis and degree of bifurcation angle. Calcified plaque length was measured in the left coronary artery with diagnostic value compared to that from coronary lumen and bifurcation angle assessments. Of 26 significant stenosis at left anterior descending (LAD) and 13 at left circumflex (LCx) on CCTA, only 14 and 5 of them were confirmed to be >50% stenosis at LAD and LCx respectively on ICA, resulting in sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 100%, 52%, 49% and 100%. The mean plaque length was measured 5.3±3.6 and 4.4±1.9 mm at LAD and LCx, respectively, with diagnostic sensitivity, specificity, PPV and NPV being 92.8%, 46.7%, 61.9% and 87.5% for extensively calcified plaques. The mean bifurcation angle was measured 83.9±13.6º and 83.8±13.3º on CCTA and ICA, respectively, with no significant difference (P=0.98). The corresponding sensitivity, specificity, PPV and NPV were 100%, 78.6%, 84.2% and 100% based on bifurcation angle measurement on CCTA, 100%, 73.3%, 78.9% and 100% based on bifurcation angle measurements on ICA, respectively. Wall shear stress was noted to increase in the LAD and LCx models with significant stenosis and wider angulation (>80º), but demonstrated little or no change in most of the coronary models with no significant stenosis and narrower angulation (<80º). This study further clarifies the relationship between left coronary bifurcation angle and significant stenosis, with angulation measurement serving as a more accurate approach than coronary lumen assessment or plaque lesion length for determining significant coronary stenosis. Left coronary bifurcation angle is suggested to be incorporated into coronary artery disease (CAD) assessment when diagnosing significant CAD.

Quantification of left coronary bifurcation angles and plaques by coronary computed tomography angiography for prediction of significant coronary stenosis: A preliminary study with dual-source CT.

PurposeTo evaluate the diagnostic performance of left coronary bifurcation angles and plaque characteristics for prediction of coronary stenosis by dual-source CT.Methods106 patients suspected of coronary artery disease undergoing both coronary computed tomography angiography (CCTA) and invasive coronary angiography (CAG) within three months were included. Left coronary bifurcation angles including the angles between the left anterior descending artery and left circumflex artery (LAD-LCx), left main coronary artery and left anterior descending artery (LM-LAD), left main coronary artery and left circumflex artery (LM-LCx) were measured on CT images. CCTA plaque parameters were calculated by plaque analysis software. Coronary stenosis ≥ 50% by CAG was defined as significant.Results106 patients with 318 left coronary bifurcation angles and 126 vessels were analyzed. The bifurcation angle of LAD-LCx was significantly larger in left coronary stenosis ≥ 50% than stenosis < 50%, and significantly wider in the non-calcified plaque group than calcified. Multivariable analyses showed the bifurcation angle of LAD-LCx was an independent predictor for significant left coronary stenosis (OR = 1.423, P = 0.002). In ROC curve analysis, LAD-LCx predicted significant left coronary stenosis with a sensitivity of 66.7%, specificity of 78.4%, positive predictive value of 85.2% and negative predictive value of 55.8%. The lipid plaque volume improved the diagnostic performance of CCTA diameter stenosis (AUC: 0.854 vs. 0.900, P = 0.045) in significant coronary stenosis.ConclusionsThe bifurcation angle of LAD-LCx could predict significant left coronary stenosis. Wider LAD-LCx is related to non-calcified lesions. Lipid plaque volume could improve the diagnostic performance of CCTA for coronary stenosis prediction.

Diagnostic Value of Coronary CT Angiography With Use of Left Coronary Bifurcation Angle in Coronary Artery Disease

Background: Atherosclerosis generally occurs in the blood vessels with angulation or curvature, however, association between coronary bifurcation angle and coronary artery disease needs to be further clarified when compared to normal patients. Objectives: The aim of this study is to determine the relationship between left coronary bifurcation angle and development of coronary artery disease when compared to patients with normal coronary arteries. Methods: Fifty patients (40 men, mean age, 55.2 years) who underwent coronary computed tomography (CT) angiography for clinical diagnosis of coronary artery disease were included in the study. Of these patients, coronary plaques were present at one or more coronary arteries in 25 patients, while in the remaining 25 cases, no plaque was detected at the coronary arteries, thus serving as the control group. Left coronary bifurcation angle between left anterior descending and left circumflex was measured on 3D volume rendering images by two assessors with >80o as the cut-off value to determine significant stenosis. Results: The mean bifurcation angle was 72.9o±19.4o (range, 36o, 112o) among 50 patients. The mean bifurcation angle was significantly wider in patients with coronary plaques than that measured in patients with normal coronary artery (p 80o, while only 12% of the patients had a bifurcation angle >80o in the control group. Conclusion: This study further confirms the direct relationship between left coronary bifurcation angle and development of coronary artery disease with diseased coronary arteries associated with wider angulation.

Relationship between left coronary artery bifurcation angle and restenosis after stenting of the proximal left anterior descending artery.

Restenosis after a percutaneous coronary intervention for proximal left anterior descending (pLAD) coronary artery disease remains a clinical challenge. However, the relationship between the left main trunk (LMT)/LAD bifurcation angle and the pLAD artery restenosis is unclear. This study examined the relationship between the LMT-LAD bifurcation angle and restenosis after stent implantation for pLAD disease. We analysed the data of 177 consecutive patients who underwent stent implantation for pLAD disease, followed by coronary angiography between December 2008 and September 2013. The LMT-LAD bifurcation angle was measured in the left or the right anterior oblique caudal (CAU) angiographic view. Out of 177 patients, 12 developed in-stent restenosis and 21 developed in-segment restenosis. The mean angle in patients with in-stent restenosis (52.2°±14.5°) in the left anterior oblique CAU view was significantly larger than that in patients without restenosis (32.0°±18.1°; P<0.001). The LMT-LAD angle in the right anterior oblique CAU view was significantly larger in patients with in-segment restenosis (27.3°±14.3°) than in patients without restenosis (17.5°±10.1°; P<0.001). Moreover, by multivariate analysis, the LMT-LAD angle was an independent predictor of in-stent and in-segment restenosis, after adjustment for significant confounders such as diabetes, hypertension, dyslipidaemia, final minimum lesion diameter and lesion length. This study suggests that a wide LMT-LAD angle is a predictor of restenosis after stent implantation for pLAD artery disease.

Coronary computed tomography angiography investigation of the association between left main coronary artery bifurcation angle and risk factors of coronary artery disease.

To explore the association between the left main coronary artery bifurcation angle and common atherosclerotic risk factors with regard to the development of coronary artery disease (CAD) using coronary computed tomography angiography (CCTA). A retrospective review of 196 CCTA cases (129 males, 67 females, mean age 58 ± 10.5 years) was conducted. The bifurcation angle between the left anterior descending (LAD) and left circumflex (LCx) was measured on two-dimensional (2D) and three-dimensional (3D) reconstructed images and the type of plaque and degree of lumen stenosis was assessed to determine the disease severity. An association between bifurcation angle and patient risk factors [gender, body mass index (BMI), hypertension, cholesterol, diabetes, smoking and family history] of CAD was also assessed to demonstrate the relationship between these variables. The mean bifurcation angle between the LAD and LCx was 79.40° ± 22.97°, ranging from 35.5° to 178°. Gender and BMI were found to have significant associations with bifurcation angle. Males were at 2.07-fold greater risk of having a >80° bifurcation angle and developing CAD than females (P = 0.003), and patients with high BMI (>25kg/m(2)) were 2.54-fold more likely to have a >80° bifurcation angle than patients with a normal BMI (P = 0.001) and thus were at greater risk of developing CAD. There is a direct relationship between the left main coronary artery bifurcation angle and patient gender and BMI. Measurement of the bifurcation angle should be incorporated into clinical practice to identify patients at high risk of developing CAD.

Computational fluid dynamic analysis of calcified coronary plaques: correlation between hemodynamic changes and cardiac image analysis based on left coronary bifurcation angle and lumen assessments

The purpose of this study was to determine the relationship between left coronary bifurcation angle and significant coronary stenosis with use of coronary CT angiography (CCTA)-generated computational fluid dynamics (CFD) analysis when compared to the CCTA analysis of coronary lumen stenosis with invasive coronary angiography (ICA) as the reference method. Eleven patients with calcified plaques at the left coronary artery tree who underwent CCTA and ICA examinations were included in the study. CFD simulation of left coronary models was performed to analyse hemodynamic changes including wall shear stress, wall pressure and flow velocity. The mean bifurcation angle was measured 83.3 ± 17.1º and 83.3 ± 17.0º on CCTA and ICA, respectively, with no significant difference (p=0.99). Of 15 significant stenosis at left anterior descending (LAD) and left circumflex (LCx) on CCTA, only 3 of them were confirmed to be >50% stenosis on ICA. Wall shear stress was noted to increase in the LAD and LCx models with significant stenosis and wider angulation (>80º), but remained no change in most of the other coronary models with no significant stenosis and narrower angulation. Wall pressured was decreased at the significant stenotic lesions, while flow velocity was increased with flow turbulence at the post-stenotic sites. This study further clarifies the direct correlation between left coronary bifurcation angle and significant stenosis, with angulation measurement being more accurate than lumen assessment for diagnosing significant stenosis.

Coronary CT angiography evaluation of calcified coronary plaques by measurement of left coronary bifurcation angle

Coronary CT angiography evaluation of calcified coronary plaques by measurement of left coronary bifurcation angle

Coronary CT Angiography in Coronary Artery Disease: Correlation between Virtual Intravascular Endoscopic Appearances and Left Bifurcation Angulation and Coronary Plaques

The aim of this study is to investigate the relationship between intraluminal appearances of coronary plaques and left coronary bifurcation angle and plaque components using coronary CT virtual intravascular endoscopy (VIE). Fifty patients suspected of coronary artery disease undergoing coronary CT angiography were included in the study. The left bifurcation angle in patients with diseased left coronary artery which was measured as 94.3° ± 16.5 is significantly larger than that in patients with normal left coronary artery, which was measured as 76.5° ± 15.9 (P < 0.001). Irregular VIE appearances were found in 10 out of 11 patients with mixed plaques in the left anterior descending (LAD) and left circumflex (LCx), while, in 29 patients with calcified plaques in the LAD and LCx, irregular VIE appearances were only noticed in 5 patients. Using 80° as a cut-off value to determine coronary artery disease, smooth VIE appearances were found in 95% of patients (18/19) with left bifurcation angle of less than 80°, while irregular VIE appearances were observed in nearly 50% of patients (15/31) with left bifurcation angle of more than 80°. This preliminary study shows that VIE appearances of the coronary lumen are directly related to the types of plaques.