The coronary artery originating from the root of the aorta is divided into the left coronary artery (LCA) and the right coronary artery(RCA). The RCA originating from the right aortic sinus of the heart supplies blood to the superior and inferior ventricles at the right side of the heart. Anomalous origin of the coronary artery (AAOCA) is a common type of congenital coronary artery anomaly[1]. Although some children are born with AAOCA, it may not be diagnosed during coronary angiography until the individual grows to an adolescent or adult [2-4]. There are four main types of AAOCA: (a) absence of the left main artery, (b) abnormal origin of the coronary artery from the improper sinus, (c) anomalous coronary ostium outside of the Valsalva's sinus, and (d) a single coronary artery[5]. Although most coronary artery anomalies have little effects on individuals, some young people who are prone to sudden cardiac death usually have the two common characteristics of abnormal: RCA and abnormal LCA[6]. This study focused on the hemodynamics of the right coronary artery originating from the left coronary sinus.
In patients undergoing coronary angiography the incidence of anomalous origin of the right coronary artery from the left esinus (AORL) is 0.92%[7]. Compared with the origin of LCA, AORL causes a lower rate of sudden death. The incidence of typical angina and myocardial infarction in patients with a low interarterial course of AORL is significantly lower than that with a high interarterial course in patients [8]. However, even if the incidence of cardiovascular disease due to AORL is relatively low, the consequences are often fatal.
A study reported that AORL can cause myocardial ischaemia, angina pectoris, myocardial infarction, and sudden cardiac death (SCD) [9-11]. The researchers find that an acute angle of AORL may cause cardiovascular disease during exercise [12]; the most proximal part of the artery has an oblique intramural course with a slit-like ostium, which may cause ischaemia [13]. Mechanical compression of the RCA due to the dilation of the pulmonary artery and aorta may result in ischaemia during maximal exercise [14, 15].
Initially, one of the causal mechanism of SCD is considered to be associated with a slit-like or flap-like closure of the orifice[16, 17]. The reported data from the large series of intravascular ultrasonography (IVUS)- based clinical studies in 63 adult patients with AORL have shown evidence that the severity of stenosis relates with the occurrence of ischemic symptoms (ie, syncope, angina, or dyspnea, in addition to SCD) [18]. The cross-sectional area at the inlet of RCA of the abnormal group is much smaller than that of the normal group in this study. One of the features of AORL is a slit-like orifice [19], so The cross-sectional area is small. The factor may cause a functional stenosis of AORL, ischemia and malignant ventricular arrhythmias [20].
In this paper, the haemodynamics of AORL were studied based on computational fluid dynamics (CFD). As a branch of hydrodynamics, CFD is increasingly being applied in biomedical engineering. Many bioengineers have used CFD to study complex cardiovascular diseases, such as coronary artery stenosis [21-26].
In this study, we hypothesised that the the hemodynamics of the right coronary artery of normal origin differed from that of AORL. 42 realistic geometic models of AORL were reconstructed based on computed tomography (CT) scan images, and then the haemodynamic was simulated with numerical method . The main purpose of this study was to investigate the effects of AORL on haemodynamics, and it provided theoretical significance for clinical evaluation of ischemic symptoms.