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Split right coronary artery is a rare congenital anomaly. Most cases originate from the same orifice in the right sinus of Valsalva. The correct diagnosis of split right coronary artery with separate ostia is believed to be extremely rare. The true incidence of this anomaly is unknown. The main problem in diagnosis is that another ostium might be missed on selective coronary angiography. The use of multidetector computed tomography has been emphasized in the diagnosis of the anomaly. Two cases of patients with a split coronary artery arising from two separate ostia are reported; the cases were both detected by conventional coronary angiography. To avoid missing the diagnosis of this rare anomaly by conventional coronary angiography, the possibility should be kept in mind and a Judkins catheter technique may be helpful.
Split right coronary artery (RCA) with two separate ostia is believed to be an extremely rare anomaly; there are few case reports in the literature. A possible reason for the low incidence arises from difficulty in diagnosis; the anomaly may have been missed in many of the studies that were based on conventional coronary angiography. Two cases of split RCA with two separate ostia diagnosed by coronary angiography are reported. It is believed that the incidence of this anomaly might be underestimated when diagnosed by conventional coronary angiography. Careful attention is necessary to avoid missing the diagnosis.
A 69-year-old man presented with atypical chest pain and underwent cardiac catheterization following a positive stress test. Contrast injection in the left coronary sinus revealed a normal left coronary artery. Subsequently, using a right Judkins catheter, an RCA ostium was engaged (Figures 1A and and1B).1B). Interestingly, while pulling back the catheter with an additional injection of contrast, angiography revealed another RCA ostium. Angiography clearly demonstrated filling of two different arteries arising from two separate ostia above the right coronary sinus (Figures 1C and and1D).1D). The anomaly was benign and the patient was medically followed up.
A 75-year-old man was admitted to the hospital with a history of chest pain at rest. He had a history of systemic hypertension and hypercholesterolemia – both risk factors for coronary artery disease. An examination of his cardiovascular system was unremarkable. Selective contrast-enhanced coronary angiography with a right coronary Judkins catheter technique revealed the RCA. When the catheter was pulled back, with additional injection of contrast, another vessel was revealed just above the origin of the RCA (Figure 2). Both arteries were free of significant narrowing. Contrast injection in the left coronary sinus demonstrated no anomalies of the left coronary artery. The patient was discharged and medically followed up.
The reported incidence of coronary artery anomalies varies between 0.2% and 2% in angiographic studies of the adult population (1,2). Of these anomalous conditions, the most common is anomalous origin of the left coronary artery from the pulmonary artery; double RCA is rare (3). There is still some controversy and confusion regarding RCA anomalies. There is no distinct definition between double RCA, and separate conus or right ventricular branch from the right sinus of Valsalva. Altun et al (4) concluded that it is difficult to interpret the anomaly as either a double RCA with a single ostium, or a high take-off of a large right ventricular branch from the right sinus of Valsalva. Sawaya et al (5) claimed that split RCA is the same anomaly as the improperly named double RCA. They also concluded that instead of two RCAs, there were split portions of the RCA branch, with two separate courses (5). Regardless of whether the anomaly is a double RCA, or a separate right ventricular or conus branch, it is rare, with few case reports. There are currently no defined data regarding the incidence of split RCAs, and only a few cases have been documented. Interestingly, most cases were reported in the Turkish population (6). This suggests that the abnormality is seen more frequently in Turkey than in other countries. Therefore, variations in the frequency of congenital coronary anomalies might have a genetic basis. However, another possibility might be that Turkish physicians are more aware of this abnormality during coronary angiography. Selective coronary angiography for RCA with too-deep engagement may miss the diagnosis. Moreover, in the reported cases, most patients presented with a double RCA arising from a single ostium. It is extremely rare and there are few case reports in which the anomaly presented with separate ostia (7,8). The main difficulty in diagnosing such cases is the separate origin of the two vessels. It is easy to miss another artery without careful attention to the possibility of the anomaly. Such anomalies with separate ostia may have been missed and the possibility excluded in many angiographic studies. This condition is commonly seen when the two orifices from the right sinus of Valsalva are far apart. To diagnose a split RCA by angiography, further evaluation, such as aortography, may be helpful. However, this may result in further time wasting and extra radiation exposure for both the patients and examiners. Thus, the true prevalence of this congenital anomaly might be underestimated by conventional angiography. The importance of multidetector computed tomography was emphasized in the diagnosis of the reported cases. It provided three-dimensional imaging of the anatomy and was more accurate in defining the origins and determining the course of the anomalous coronary arteries than conventional coronary angiography (9).
The exact incidence of split RCAs is uncertain. Recognition of coronary artery anomalies is important in patients undergoing coronary angiography, particularly in patients who will receive coronary interventions and undergo cardiac surgery. When a congenital coronary anomaly presents with two separate ostia, the correct diagnosis is difficult when it is based on conventional coronary angiography; physicians need to pay careful attention to this issue.
The true incidence of separate ostia in the RCA is not known. To diagnose this anomaly by coronary angiography, the possibility of its occurrence should be kept in mind; further awareness is necessary. Additional injection of contrast above the ascending aorta site while slowly pulling back the catheter during selective coronary angiography may support the diagnosis.