FULL TITLE: Anomalous Origin of the RCA from the Proximal LAD and a Single Coronary Artery Anomaly: Two Case Reports of Two Rare Coronary Anomalies
From the Providence Heart Institute, Southfield, Michigan. The authors report no conflicts of interest regarding the content herein. Manuscript submitted April 23, 2009, provisional acceptance given May 7, 2009, and final version accepted June 3, 2009. Address for correspondence: Rayan Hourani, MD, Providence Heart Institute, 16001 West Nine Mile Road, Southfield, MI 48075. E-mail: firstname.lastname@example.org
J INVASIVE CARDIOL 2009;21:E216-E217
Coronary artery anomalies are present at birth, but are usually asymptomatic and are found incidentally during coronary angiography. Their prevalence is less than 1.3% based on published series.1–4 The most common coronary anomaly is separate origination of the left anterior descending (LAD) and left circumflex (LCX) arteries from the left sinus of Valsalva. The second most common anomaly is origination of the LCX artery from the right coronary artery (RCA) or right sinus of Valsalva. Anomalous origin of the RCA from the LAD is very rare, as is a single coronary artery anomaly in which the three major coronary arteries arise from the same ostium off the right sinus of Valsalva. In fact, patients with an isolated single coronary anomaly may present with symptoms such as angina pectoris, myocardial infarction, arrhythmias, syncope, and even sudden cardiac death.5–7 This anomaly is one of the rarest coronary anomalies, comprising less than 3% of all coronary anomalies. In this article, we report two cases. One case demonstrates a rare anomaly in which the RCA takes off from the proximal LAD. The other case demonstrates a single coronary artery anomaly with the LAD and LCX arteries arising separately from the proximal RCA.8,9 Case 1. 56-year-old male with hypertension and chronic bronchitis was evaluated for worsening shortness of breath. His surface electrocardiogram (ECG) showed normal sinus rhythm with few premature ventricular complexes. We elected to proceed with a myocardial perfusion study, which showed global left ventricular hypokinesis. There was a small, fixed perfusion defect on both rest and stress images seen at the apical inferior wall of the left ventricle. Coronary angiography was performed through the right femoral artery using the Judkin’s technique. Cannulation of the left main coronary artery displayed normal courses of the left main, LCX, and LAD associated with a 20% stenosis in the proximal LAD (Figure 1). An anomalous RCA as a separate small branch arose from the proximal LAD just before the first septal branch, then coursed anteriorly down the right atrioventricular groove. Left ventriculography demonstrated global hypokinesia with an ejection fraction Case 2. 57-year-old male with hypertension and hyperlipidemia presented to our clinic with worsening dyspnea on exertion. His resting ECG showed a normal sinus rhythm with no ST-segment abnormalities. The patient was referred for a myocardial perfusion stress imaging study that revealed a large area of reversible ischemia in the basal, mid, and apical inferior and lateral segments. Coronary angiography demonstrated that all three major coronary arteries were originating from the same ostium in the right sinus of Valsalva (Figure 2). The RCA was a dominant vessel with a large posterior descending artery and posterolateral branch arteries. There was a high-grade 90% stenosis in the proximal RCA. The LAD and LCX took off proximally from the RCA. The LAD coursed to the left side into the anterior interventricular groove. The LCX artery gave rise to an obtuse marginal artery. Both the LAD and LCX had mild, diffuse, noncritical disease. Left ventriculography revealed preserved systolic function. The proximal obstructive lesion in the RCA was successfully treated with balloon angioplasty and a 3.5 x 12 mm stent was successfully deployed. Multidetector computed tomographic (MDCT) coronary angiography was performed for further delineation of the coronary anatomy (Figure 3). A single coronary artery was identified arising from the right coronary cusp. It immediately gives off the LCX artery, which travels between the aortic root and the right atrium down to the left atrioventricular groove. The LAD artery courses anteriorly to the right ventricular outflow tract. The patient returned for follow up 6 months later. His dyspnea had improved significantly and he is still enrolled in our cardiac rehabilitation program. Discussion. Both patients reported above, although they had rare abnormal coronary anatomies, remained asymptomatic until later in life. The first patient had nonischemic cardiomyopathy and his symptoms were probably not secondary to his coronary artery disease. The second patient developed a critical stenosis in the normally arising RCA. Based on the largest angiographic review by Yamanaka and Hobbs,1 the incidence of congenital coronary artery anomalies was reported to be 1.3%. The RCA arising as a branch from the LAD is a very rare anomaly. Very few patients with this anomaly were reported in the literature.10–15 To date, no case reports have been published about an RCA arising from the proximal segment of the LAD. Most of the reported anomalies demonstrated the RCA arising from the mid-LAD after the first septal perforator branch. We report the first case of a RCA originating from the proximal LAD and before the takeoff of the first septal branch. To our knowledge, there has been no reported increased mortality or morbidity in this kind of anomaly. On the other hand, all three major coronary arteries arising from the right sinus of Valsalva can potentially be associated with worse prognosis, depending on the course of the major vessels.5–7 Usually, these patients present with syncope or sudden cardiac death before they reach their fourth decade of life. Our patient was 57 years old with no history of syncope, which made his risk for sudden cardiac death due to coronary anomaly extremely low. His cardiac CT study demonstrated a benign anatomy, meaning no major coronary vessel traveling between the aorta and the pulmonary artery. In conclusion, both of these cases demonstrate a relatively benign course and favorable prognosis of these very rare coronary anomalies.