Left Coronary Artery Tree Research Articles

Transient formation of collaterals contributes to the restoration of the arterial tree during cardiac regeneration in neonatal mice

Revascularization of ischemic myocardium following cardiac damage is an important step in cardiac regeneration. However, the mechanism of arteriogenesis has not been well described during cardiac regeneration. Here we investigated coronary artery remodeling and collateral growth during cardiac regeneration. Neonatal MI was induced by ligature of the left descending artery (LAD) in postnatal day (P) 1 or P7 pups from the Cx40-GFP mouse line and the arterial tree was reconstructed in 3D from images of cleared hearts collected at 1, 2, 4, 7 and 14 days after infarction. We show a rapid remodeling of the left coronary arterial tree induced by neonatal MI and the formation of numerous collateral arteries, which are transient in regenerating hearts after MI at P1 and persistent in non-regenerating hearts after MI at P7. This difference is accompanied by restoration of a perfused or a non-perfused LAD following MI at P1 or P7 respectively. Interestingly, collaterals ameliorate cardiac perfusion and drive LAD repair, and lineage tracing analysis demonstrates that the restoration of the LAD occurs by remodeling of pre-existing arterial cells independently of whether they originate in large arteries or arterioles. These results demonstrate that the restoration of the LAD artery during cardiac regeneration occurs by pruning as the rapidly forming collaterals that support perfusion of the disconnected lower LAD subsequently disappear on restoration of a unique LAD. These results highlight a rapid phase of arterial remodeling that plays an important role in vascular repair during cardiac regeneration.

Investigation of the Relationship between Right Coronary Artery-Aorta Angle and Coronary Artery Disease and Associated Risk Factors.

At the level of the left coronary artery tree, there is evidence showing an association between bifurcation angle and coronary artery disease (CAD), and this motivated us to explore similar associations at the level of the right coronary artery (RCA). The purpose of this study was to determine whether there is a relationship between RCA-aorta angle and CAD and age, sex, body mass index, smoking status, hypertension, and high blood cholesterol. The coronary computed tomography angiography datasets and CAD risk factor checklists of 250 patients were retrospectively reviewed, with RCA-aorta angles measured via multiplanar reformation images. Independent t-tests were used to compare mean RCA-aorta angle measurements between groups, correlations between continuous variables were assessed using Pearson and Spearman correlations, and a general linear model was used to adjust for potentially confounding variables. Coronary angle measurements were conducted by two independent assessors with very strong intraclass correlation (r=0.999, p<0.001). A significantly smaller mean RCA-aorta angle was observed in the CAD group (79.07 ± 24.88°) compared to the normal group (92.08 ± 19.51°, p=0.001), in smokers (76.63 ± 22.94°) compared to non-smokers (85.25 ± 23.84°, p=0.016), and a narrow RCA-aorta angle was negatively correlated with BMI (r=-0.174, p=0.010). This study suggests a relationship between narrow RCA-aorta angles and CAD, smoking, and increasing BMI.

Visualization of multiphase pulsatile blood over single phase blood flow in a patient specific stenosed left coronary artery using image processing technique.

Coronary arteries disease has been reported as one of the principal roots of deaths worldwide. The aim of this study is to analyze the multiphase pulsatile blood flow in the left coronary artery tree with stenosis. The 3D left coronary artery model was reconstructed using 2D computerized tomography (CT) scan images. The Red Blood Cell (RBC) and varying hemodynamic parameters for single and multiphase blood flow conditions were analyzed. Results asserted that the multiphase blood flow modeling has a maximum velocity of 1.017 m/s and1.339 m/s at the stenosed region during the systolic and diastolic phases respectively. The increase in Wall Shear Stress (WSS) observed at the stenosed region during the diastole phase as compared during the systolic phase. It was also observed that the highest Oscillatory Shear Index (OSI) regions are found in the downstream area of stenosis and across the bifurcations. The increase in RBCs velocity from 0.45 m/s to 0.6 m/s across the stenosis was also noticed. The computational multiphase blood flow analysis improves the understanding and accuracy of the complex flow conditions of blood elements (RBC and Plasma) and provides the progression of the disease development in the coronary arteries. This study helps to enhance the diagnosis of the blocked (stenosed) arteries more precisely compared to the single-phase blood flow modeling.

The Use of Digital Coronary Phantoms for the Validation of Arterial Geometry Reconstruction and Computation of Virtual FFR

We present computational fluid dynamics (CFD) results of virtual fractional flow reserve (vFFR) calculations, performed on reconstructed arterial geometries derived from a digital phantom (DP). The latter provides a convenient and parsimonious description of the main vessels of the left and right coronary arterial trees, which, crucially, is CFD-compatible. Using our DP, we investigate the reconstruction error in what we deem to be the most relevant way—by evaluating the change in the computed value of vFFR, which results from varying (within representative clinical bounds) the selection of the virtual angiogram pair (defined by their viewing angles) used to segment the artery, the eccentricity and severity of the stenosis, and thereby, the CFD simulation’s luminal boundary. The DP is used to quantify reconstruction and computed haemodynamic error within the VIRTUheartTM software suite. However, our method and the associated digital phantom tool are readily transferable to equivalent, clinically oriented workflows. While we are able to conclude that error within the VIRTUheartTM workflow is suitably controlled, the principal outcomes of the work reported here are the demonstration and provision of a practical tool along with an exemplar methodology for evaluating error in a coronary segmentation process.

Fluid\u2013structure interactions (FSI) based study of low-density lipoproteins (LDL) uptake in the left coronary artery

The purpose of this study is to compare the effect of the different physical factors on low-density lipoproteins (LDL) accumulation from flowing blood to the arterial wall of the left coronary arteries. The three-dimensional (3D) computational model of the left coronary arterial tree is reconstructed from a patient-specific computed tomography angiography (CTA) image. The endothelium of the coronary artery is represented by a shear stress dependent three-pore model. Fluid–structure interaction (FSI) based numerical method is used to study the LDL transport from vascular lumen into the arterial wall. The results show that the high elastic property of the arterial wall decreases the complexity of the local flow field in the coronary bifurcation system. The places of high levels of LDL uptake coincide with the regions of low wall shear stress. In addition, hypertension promotes LDL uptake from flowing blood in the arterial wall, while the thickened arterial wall decreases this process. The present computer strategy combining the methods of coronary CTA image 3D reconstruction, FSI simulation, and three-pore modeling was illustrated to be effective on the simulation of the distribution and the uptake of LDL. This may have great potential for the early prediction of the local atherosclerosis lesion in the human left coronary artery.

Bifurcation Asymmetry of Small Coronary Arteries in Juvenile and Adult Mice.

Background: Microvascular bifurcation asymmetry is of significance for regulation of coronary flow heterogeneity during juvenile and adult growth. The aim of the study is to investigate the morphometric and hemodynamic variation of coronary arterial bifurcations in mice of different ages.Methods: Pulsatile blood flows were computed from a Womersley-type model in the reconstructed left coronary arterial (LCA) trees from Micro-CT images in normal mice at ages of 3 weeks, 6 weeks, 12 weeks, 5-6 months, and >8 months. Diameter and flow ratios and bifurcation angles were determined in each bifurcation of the LCA trees.Results: The blood volume and inlet flow rate of LCA trees increase and decrease during juvenile and adult growth, respectively. As vessel diameters decrease, the increased ratios of small to large daughter vessel diameters (Ds/Dl) result in more uniform flows and lower velocities. There are significant structure-functional changes of LCA trees in mice of >8 months compared with mice of < 8 months. As Ds/Dl increases, the variation trend of bifurcation angle during juvenile growth is different from that during adult growth.Conclusions: Although inlet flows are different in adult vs. juvenile mice, the adult still have uniform flow and low velocity. This is accomplished through a decrease in diameter. The design ensures ordered dispersion of red cells through asymmetric branching patterns into the capillaries.

The Structure‐function Remodeling and Therapeutic Effect of Tongxinluo Capsule in Rabbit Hearts of Myocardial Infarction

ObjectiveAnimal models are important to study basic mechanism of ischemic heart failure (HF). The objective of the study was to create rabbit models of myocardial infarction to investigate the structure‐function remodeling of the left ventricle (LV) and coronary arterial trees and the therapeutic effects of Tongxinluo Capsule.MethodNew Zealand white rabbits were randomly divided into sham group, model group and therapeutic group. The rabbit models were created through multiple coronary artery ligations. Echocardiographic, Micro‐CT and histological measurements were performed at postoperative 6 weeks and postoperative 12 weeks, respectively.ResultEchocardiographic measurements of the model group showed an approximately monotonic slope of ejection fraction and fractional shortening from 73% and 40% to 58% and 28% as well as persistent enlargement of LV cavity and slight mitral regurgitation at postoperative 12 weeks. Measurements of micro‐CT and histology revealed that coronary vascular sparseness and cardiac fibrosis related to inflammation occurred concurrently in adjacent zone of MI at postoperative 12 weeks although there was compensatory vascular growth at postoperative 6 weeks. Compared with the model group, the therapeutic group presented significant improvements in ejection fraction, fractional shortening, LV end‐systolic dimension and volume of cardiac output. The number of capillary vessels increased distinctly, while the infarct area decreased correspondingly.ConclusionsIn conclusion, these findings validate the proposed rabbit model and prove that the interaction of the degenerated coronary vasculature and increased ventricle wall stress relevant to cardiac fibrosis in vicinity of myocardial infarction (MI) facilitates the occurrence and development of ischemic HF. Furthermore, Tongxinluo Capsule has been proved in our study to play an essential role in protecting myocardium, improving blood supply of myocardium and relieving myocardial injury. To summarize, the post‐MI rabbit model can serve as a reference to test various drugs for treatment of ischemic HF, and contributes to the clinical application of Tongxinluo Capsule in the future.Support or Funding InformationThis research is supported in part by the National Natural Science Foundation of China Grant 11372010, 11672006 (Y Huo); Shenzhen Science and Technology Innovation Institution (China) Grant JCYJ20160427170536358 (Y Huo); and Hebei University (China) Grant 2015A1002 (Y Huo).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Impact of spatial characteristics in the left stenotic coronary artery on the hemodynamics and visualization of 3D replica models

Cardiovascular disease has been the major cause of death worldwide. Although the initiation and progression mechanism of the atherosclerosis are similar, the stenotic characteristics and the corresponding medical decisions are different between individuals. In the present study, we performed anatomic and hemodynamic analysis on 8 left coronary arterial trees with 10 identified stenoses. A novel boundary condition method had been implemented for fast computational fluid dynamics simulations and patient-specific three-dimensional printed models had been built for visualizations. Our results suggested that the multiple spatial characteristics (curvature of the culprit vessel multiplied by an angle of the culprit’s vessel to the upstream parent branch) could be an index of hemodynamics significance (r = −0.673, P-value = 0.033). and reduction of the maximum velocity from stenosis to downstream was found correlated to the FFRCT (r = 0.480, p = 0.160). In addition, 3D printed models could provide accurate replicas of the patient-specific left coronary arterial trees compare to virtual 3D models (r = 0.987, P-value < 0.001). Therefore, the visualization of the 3D printed models could help understand the spatial distribution of the stenoses and the hand-held experience could potentially benefit the educating and preparing of medical strategies.

The Structure-function remodeling in rabbit hearts of myocardial infarction.

Animal models are of importance to investigate basic mechanisms for ischemic heart failure (HF). The objective of the study was to create a rabbit model through multiple coronary artery ligations to investigate the postoperative structure‐function remodeling of the left ventricle (LV) and coronary arterial trees. Here, we hypothesize that the interplay of the degenerated coronary vasculature and increased ventricle wall stress relevant to cardiac fibrosis in vicinity of myocardial infarction (MI) precipitates the incidence and progression of ischemic HF. Echocardiographic measurements showed an approximately monotonic drop of fractional shortening and ejection fraction from 40% and 73% down to 28% and 58% as well as persistent enlargement of LV cavity and slight mitral regurgitation at postoperative 12 weeks. Micro‐CT and histological measurements showed that coronary vascular rarefaction and cardiac fibrosis relevant to inflammation occurred concurrently in vicinity of MI at postoperative 12 weeks albeit there was compensatory vascular growth at postoperative 6 weeks. These findings validate the proposed rabbit model and prove the hypothesis. The post‐MI rabbit model can serve as a reference to test various drugs for treatment of ischemic HF.

Hemodynamics in Coronary Arterial Tree of Serial Stenoses.

Serial segmental narrowing frequently occurs in humans, which alters coronary hemodynamics and further affects atherosclerotic progression and plaque formation. The objective of this study was to understand the distribution of hemodynamic parameters in the epicardial left main coronary arterial (LMCA) tree with serial stenoses reconstructed from patient computer tomography angiography (CTA) images. A finite volume method was used in conjunction with the inlet pressure wave and outlet flow resistance. The time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) were determined from the flow field. A stenosis at a mother vessel mainly deteriorated the hemodynamics near the bifurcation while a stenosis at a daughter vessel affected the remote downstream bifurcation. In comparison with a single stenosis, serial stenoses increased the peak pressure gradient along the main trunk of the epicardial left anterior descending arterial tree by > 50%. An increased distance between serial stenoses further increased the peak pressure gradient. These findings have important implications on the diagnosis and treatment of serial coronary stenoses.

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.

Remodeling of left circumflex coronary arterial tree in pacing-induced heart failure.

Congestive heart failure (CHF) is a very serious heart disease that manifests an imbalance between left ventricle supply and demand. Although the mechanical demand of the failing heart has been well characterized, the systematic remodeling of the entire coronary arterial tree that constitutes the supply of the myocardium is lacking. We hypothesize that the well-known increase in ventricle wall stress during CHF causes coronary vascular rarefaction to increase the vascular flow resistance, which in turn compromises the perfusion of the heart. Morphometric (diameters, length, and numbers) data of the swine left circumflex (LCx) arterial tree were measured in both CHF (n = 6) and control (n = 6) groups, from which a computer reconstruction of the entire LCx tree was implemented down to the capillary level to enable a hemodynamic analysis of coronary circulation. The vascular flow resistance was increased by ∼75% due to a significant decrease of vessel numbers (∼45%) and diameters in the first capillary segments (∼10%) of the LCx arterial tree after 3-4 wk of pacing. The structural remodeling significantly changed the wall shear stress in vessel segments of the entire LCx arterial tree of CHF animals. This study enhances our knowledge of coronary arterial tree remodeling in heart failure, which provides a deeper understanding of the deterioration of supply-demand relation in left ventricle.

Hemodynamic analysis of patient-specific coronary artery tree.

Local hemodynamic parameters, such as wall shear stress (WSS), oscillatory shear index and relative resident time (RRT), have been linked to coronary plaque initiation and progression. In this study, a left coronary artery tree model was reconstructed from computed tomography angiography images of a patient with multiple stenoses. The geometry of the coronary artery tree model was virtually restored by eliminating the lesions, essentially re-creating the virtually healthy artery anatomy. Using numerical simulations, flow characteristics and hemodynamic parameter distributions in the stenosed and virtually healthy models were investigated. In the virtually healthy artery model, disturbed flows were found at four locations, prone to initialization of plaque formation. Low WSS and high RRT were exhibited in three of the four locations, and high WSS and low RRT were exhibited in the fourth. These findings suggest that coronary plaque is more likely to form in locations with disturbed flow conditions characterized by low WSS and high RRT or high WSS and low RRT. In addition, clinical index of fractional flow reserve was found to significantly correlate with blood flow rate, rather than anatomic parameters, such as diameter stenosis, which implied the importance of hemodynamic environment in stenosis formation.

Coronary CT angiography (cCTA): automated registration of coronary arterial trees from multiple phases

Coronary computed tomography angiography (cCTA) is a commonly used imaging modality for the evaluation of coronary artery disease. cCTA is generally reconstructed in multiple cardiac phases because different coronary arteries may be better visualized in some phases than in others due to the periodic cardiac motion. We are developing an automated registration method for coronary arterial trees from multiple-phase cCTA that has potential application in building a ‘best-quality’ tree to facilitate image analysis and detection of stenotic plaques. Given the segmented left or right coronary arterial (LCA or RCA) trees from the multiple phases as input, the adjacent phase pairs, where displacements are relatively small, are registered by a specifically designed method based on a cubic B-spline with fast localized optimization (CBSO). For the phase pairs with large displacements, a global registration using an affine transform with quadratic terms and nonlinear simplex optimization (AQSO) is followed by a local registration using CBSO to refine the AQSO registered volumes. 26 LCA and 26 RCA trees with six cCTA phases from 26 patients were used for registration evaluation. The average distances for the tree pairs between the adjacent phases with small displacements before and after CBSO registration were 0.96 ± 0.79 and 0.76 ± 0.61 mm respectively for LCA, and 0.93 ± 0.97 and 0.64 ± 0.43 mm, respectively for RCA. The average distance differences before and after registration were statistically significant (p < 0.001) for both LCA and RCA trees. The average distances for the distant phases with large displacements before registration, after AQSO registration, and finally after the CBSO registration were 2.85 ± 1.46, 1.62 ± 0.76, and 0.97 ± 0.43 mm, respectively for LCA, and 4.03 ± 2.36, 2.18 ± 1.11, and 0.97 ± 0.44 mm, respectively for RCA. The average distance differences between every two consecutive stages of registration were statistically significant. The corresponding phases of LCA and RCA trees were aligned to an average of less than 1 mm, providing a basis for a best-quality tree construction.

Construction of a 3D coronary map to assess geometrical information in-vivo from coronary patients

Traditional risk factors are involved in the development of coronary artery disease (CAD), but geometrical risk factors have also proved to be determinant. In this work we present a new method to construct a 3D map of the left coronary artery tree using CT image processing and skeletonization techniques. We computed cumulative length-volume functions through the coronary tree bifurcations and also the relationships between total tree volumes, total length, number of segments and bifurcations with respect to the presence and severity of atherosclerotic plaques. A total of 65 patients, 40 with and 20 without CAD were recruited. We found more vascular segments and bifurcations per patient in the CAD group. Accordingly, total cumulative length was longer in CAD patients (p<0.01) whereas total cumulative volume was similar between groups. Cumulative length-volume (L-V) relationships conformed to an allometric function L = KV.Vβ. The allometric slope β≈0.75 did not change with disease, whereas the allometric constant KV was lower in the healthy group (p<0.05) consistent with the literature. These results suggest that CAD patients follow a compensatory mechanism, dilating the vessels to maintain a normal coronary flow. The 3D coronary map offers useful quantitative information of the coronary morphometry.

Two circumflex arteries originating from both right and left coronary sinuses of Valsalva

A 75-year-old woman with a history of chest discomfort was referred to our clinic. Following physical examination and initial tests, a diagnostic coronary arteriography was planned. Left coronary arteriography revealed a normal left main coronary artery (LMCA) originating from the left sinus of Valsalva. The LMCA was branching into the left anterior descending (LAD) and left circumflex (Cx) arteries (Fig. 1). When the right coronary ostium was cannulated, another Cx artery was noticed in addition to a right coronary artery (RCA) (Fig. 2). Most of the cases with anomalous origin of the Cx artery, the initial course is posterior to the aorta. An interarterial course of a Cx artery is a very rare condition. In this case, mild ectasia or interarterial course might be responsible for her symptoms. A multislice computed tomography was planned to show the course, but she refused to take additional radiation. In cases of double Cx artery, origination of the Cx artery as a proximal branch of the RCA or separate branch from right sinus of Valsalva has been previously reported [1]. This case illustrates dual Cx artery with a common ostium with RCA. Fig. 1 Coronary angiogram in the right caudal view shows the left coronary artery tree with a circumflex artery Fig. 2 Coronary angiogram in the left anterior oblique caudal view shows the circumflex artery originating from right sinus of Valsalva

Modelling of blood flow resistance for an atherosclerotic artery with multiple stenoses and poststenotic dilatations

Modelling of blood flow resistance for an atherosclerotic artery with multiple stenoses and poststenotic dilatations

High Origination of the Right Coronary Artery in a 58‐Year‐Old Woman: An Unusual Congenital Coronary Artery Anomaly

A 58-year-old woman underwent coronary angiography because of exertional angina pectoris (New York Heart Association class II). She had a history of arterial hypertension for 13 y. The right coronary artery (RCA) was not visualized during diagnostic angiography. Ascending aortography showed that an ectopic RCA ostium located on the left surface of the ascending aorta several centimeters above the sinotubular junction (Figure 1A). On the basis of aortographic data, we were able to selectively cannulate the RCA ostium using a left Amplatz-type catheter (Figure 1B) (Asahi Intecc CD., LTD Akatsuki-cho, Scto-chi, Aichi, Japan). Anomalous RCA, as well as, the left coronary arterial tree were found to be normal.

Prediction Rules for the Detection of Coronary Artery Plaques

To evaluate spatial plaque distribution patterns in coronary arteries based on computed tomography coronary angiography data sets and to express the learned patterns in prediction rules. An application is proposed to use these prediction rules for the detection of initially missed plaques. Two hundred fifty two consecutive patients with chronic coronary artery disease underwent contrast-enhanced dual-source computed tomography coronary angiography for clinical indications. Coronary artery plaques were manually labeled on a 16-segment coronary model and their position (ie, segments and bifurcations) and composition (ie, calcified, mixed, or noncalcified) were noted. The frequent itemset mining algorithm was used to statistically search for plaque distribution patterns. The patterns were expressed as prediction rules: given plaques at certain locations as conditions, a prediction rule gave evidence--with a certain confidence value--for a plaque at another location within the coronary artery tree. Prediction rules with the highest confidence values were evaluated and described. Furthermore, to improve manual plaque detection, all prediction rules were applied on the patient data to search for segments with potentially missed plaques. These segments were then reviewed in a second, guided reading for the existence of plaques. The same number of segments was also determined by a weighted random approach to evaluate the quality of prediction resulting from frequent itemset mining. In 200 of 252 (79.4%) patients, at least one coronary plaque (range, 1-22 plaques) was found. In total 1229 plaques (990 calcified, 80.6%; 227 mixed, 18.5%; 12 noncalcified, 1%) distributed, over 916 coronary segments and 507 vessels were manually labeled. Four plaque distribution patterns were identified: 20.6% of the patients had no plaques at all; 31.7% had plaques in the left coronary artery tree; 46.4% had plaques both in left and right coronary arteries, whereas 1.2% of the patients had plaques solely in the right coronary artery (RCA). General rules were found predicting plaques in the left anterior descending artery (LAD), given plaques in segments of the RCA or in the left main artery. Further general rules predicted plaques in the LAD, given plaques in the circumflex artery. In the guided review, the segment selection based on the prediction rules from frequent itemset mining performed significantly better (P < 0.001) than the weighted random approach by revealing 48 initially missed plaques. This study demonstrates spatial plaque distribution patterns in coronary arteries as determined with cardiac CT. Use of the frequent itemset mining algorithm yielded rules that predicted plaques at certain sites given plaques at other sites of the coronary artery tree. Use of these prediction rules improved the manual labeling of coronary plaques as initially missed plaques could be predicted with the guided review.

Congenital Atresia of the Left Main Coronary Artery Associated With Patent Ductus Arteriosus and Aortic Regurgitation

Congenital left main coronary artery (LMCA) atresia is a rare anomaly and surgical revascularization is recommended once the diagnosis is confirmed. In some cases, LMCA atresia will coexist with other cardiac anomalies, mostly in pediatric patients. A 32-year-old woman had congenital LMCA atresia associated with patent ductus arteriosus (PDA), aortic regurgitation (AR), and moderate pulmonary hypertension. The PDA and AR were repaired surgically and the patient's symptoms improved. Coronary revascularization was not performed because the LCA was supplied by 2 large conus arteries, as "naturally occurring" bypass arteries. The patient remained asymptomatic at the 2.5-year follow-up visit. Given the positive outcome in this patient, surgical repair of the associated cardiac defect without coronary revascularization may be a reasonable approach for patients with congenital LMCA atresia, in which the left coronary arterial tree is supplied by other "naturally occurring" bypass arteries.