Anomalous origin of the right coronory artery from the left sinus of Valsalva ia a rare built clinically significant congenital abnormality, difficult to diagnose angigraphically. We describe a patient in whom magnetic resonance imaging was used to delineate the anomalous course of the right coronary artery following angiographic demonstration limited by technical coinsiderations.
Anomalous origins of coronary catheterization.[1-3] They include origin of the circumflex from the right sinus of Valsalva with a 0.45 percent incidence, origin of the left anterior descending from the right sinus of Valsalva with a 0.2 percent incidence, and origin of the left main from the pulmonary artery with a 0.04 percent incidence.[1,4] One of the lest frequent anomalies is the right coronary artery (RCA) arising from the left sinus of Valsalva with a reported incidence of 0.02 percent to 0.16 percent.[4,5] Although this anomaly is rare, its recognition is clincally important, especiaally its course, since it is associated with agina pectoris, myocardial infarction, syncope, and sudden deaath.[6-7] We descrive a patient in whom magnetic resonance imaging (MRI) was used to delineate the anomalous course of the RCA following angioghraphic demonstration that was limited by technical considerations.
A 54-year-old black man was admitted to the surgical service for excision of a right axillary hidradentis. Cardiology physicians were consulted following surgery because the patient experienced chest pain. The patient admitted to having pain for the previous 4 to 5 months. The pain was dull, oppressive, retrosternal, and ofte radiated to the left arm. It was brought on with exertion and relieved with rest. It was associated with shortness of breath and diaphoresis. During the preceding four months, the patient had also experienced six bouts of postexertional syncope. His medical history was significant for hypertension for five years.
Physician examination revealed blood pressure of 150/100 mm Hg with no orthostatic changes. An ECG showed early repolarization changes in lateral leads. Echocardiogram showed normal left and right ventricular size, thickness, and function. Exercise stress test was terminated 3 min and 49 is into exercise when the patient experienced typical chest pain at peak exercise. The pain resolved 2 min after cessation of exercise. The patient achieved only 69 percent of his maximum predicted heart rate. No diagnostic ECG changes were noted.
Cardiac catheterization was performed that showed normal hemodynamics, normal left ventricular systolic function, and 1 + mitral regurgitation. The coronary angiogram showed the following: a 60 percent proximal stenosis in the left anterior and descending artery and a 70 percent eccentric lesion of the distal circumflex. An anomalous origin of the RCA from the left coronary cusp was noted (Fig 1). Though it appeared that the RCA corsed between the aorta and pulmonary artery, confirmation of the same could not be obtained due to technical problems in positioning this postsurgical patient in the left lateral position with the arm abducted.
As the exact course of the RCA was not obtained, the patient was referred to MRI to assess the same. Multiple [T.sub.1]-weighed spin echo images through the region of the aortic root were obtained. The RCA was found to have an anomalous origin from the anterior aspect of the aorta. A short portion coursed between the aorta and the right ventricular outflow tract before entering a normal position in the atrioventricular groove (Fig 2).
Anomalies representing the greatest risk in adults for significant cardiac morbidity and morality are the left main coronary artery originating from the right sinus of Valsaalva, and the RCA arising from the left sinus of Valsalva, coursing between the aorta and pulmonary artery. The high risk of these anomalies may be related to the slit-like opening of the vessels caused by their acute take-off angle from the aortic root that would tend to narrow with aortic dilation incduced by exercise or to the compression of the coronary artery between the great vessels.
Sudden death is not an uncommon presentation for this anomaly, occuring in up to 30 percent of patients according to one report. Therefore, in patients suspected of having this anomaaly, every attempt must be made for its diagnosis and surgical correction. Aniographic demonstration of this anomaly is often difficult as exemplified by our case and also reported by others. Currently, there does not seem to be a consensus on an ideal noninvasive technique to diagnose or confirm suspected cases. Several cases have been described in which transesophageal ecocardiography supplemented the information obtained from cardiac catheterization. Magnetic resonance imaging has been used to evaluate patency of bypass grafts. and to evaluate various coronary artery anomalies such as aneurysm and fitstuals. We believe ours is the first case in which MRI has been used to document an anomalous course of the right coronary artery.
Magnetic resonance imaging appears to be a promising tool in confirming the origin and course of anomalous coronary arteries in difficult cases.
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