CASE REPORTS

An Unusual Congenital Coronary Anomaly: Origin of the Left
Circumflex Coronary Artery from a Right Coronary Artery
Arising fro

Rosario Fiorilli, MD, Antonio Parma, MD, Roberto Violini, MD
Rosario Fiorilli, MD, Antonio Parma, MD, Roberto Violini, MD

Congenital coronary anomalies are relatively uncommon, with a prevalence varying from 0.3% of autopsy series1 to 1.2% of angiographic studies.2 Such anomalies may occur in several anatomical arrangements, with different clinical significance, which have been meticulously classified in a number of reviews.3–5 Here we describe a previously unreported coronary anomaly associated with an obstructive atherosclerotic coronary lesion, which was successfully treated by coronary angioplasty.

Case Report. A 54-year-old male was referred to our institution for evaluation of a 4-month history of exertional angina, with a positive exercise test. Risk factors for coronary artery disease included hyperlipidemia and arterial hypertension. His clinical examination and resting electrocardiogram (ECG) were unremarkable. A 2-dimensional echocardiogram demonstrated normal left ventricular function, with an ejection fraction of 60%.

Coronary angiography was performed through the right femoral artery. Contrast injection in the left coronary ostium revealed a normal left anterior descending artery, without distribution to the left lateral wall (Figure 1). Multiple attempts with different diagnostic catheters failed to engage the right coronary artery in its usual position.

 

Nonselective contrast injection disclosed the origin of the right coronary artery from the left sinus of Valsalva (Figure 2), and the vessel was eventually able to be cannulated with an Amplatz left I catheter (Cordis Corp., Miami, Florida). The coronary artery arose from the anterior part of the left coronary sinus, then turned immediately rightward in an acute angle and subsequently followed the normal course in the right atrioventricular groove, where a tight, eccentric stenosis was present. The distal portion of the vessel reached the crux cordis bifurcating into the posterior descending and the posterolateral branches (dominant right coronary artery).

Approximately 2.3 cmpast its aortic origin, the right coronary artery gave rise to the circumflex coronary artery, which was directed posteriorly towards the left lateral wall of the left ventricle, showing no significant disease (Figure 3).

A decision was made to dilate the stenosis of the right coronary artery. After many unsuccessful attempts of selective engagement of the abnormal vessel using different guiding catheters, adequate cannulation and good support were finally achieved with a 6 Fr XB 3.5 guiding catheter (Cordis), reshaped with a hot-air gun to deflect its tip with an additional 45° angulation. With a clockwise rotation, the tip of the catheter engaged the ostium of the anomalous right coronary artery and allowed advancement of a 0.014 inch BMW guidewire (Guidant Corp., Indianapolis, Indiana).

 

The stenosis was predilated with a 2.5 x 10 mm Aqua balloon (Cordis), and an Endeavor 2.5 x 14 mm stent (Medtronic, Inc., Minneapolis, Minnesota) was implanted, with a good angiographic result (Figures 4A and B). The procedure time was 2 hours, with 50 minutes of fluoroscopy and 400 ml of contrast used. Most of the resources were employed identifying the best diagnostic and guiding catheters.

The patient had an uneventful hospital course and was discharged the following day. Two weeks later, multislice computed tomography (MSCT) was performed in order to evaluate the course of the coronary anomaly. Using the LightSpeed Pro (General Electric, Milwaukee, Wisconsin) 16-slice CT system, the entire heart was scanned with the following parameters: slice thickness of 0.6 mm, rotational time of 0.4 seconds, 500 mA, pitch 0.2, and retrospective ECG-gating technique.

No coronary ostium was found in the right sinus of Valsalva.

 

The abnormal vessel was seen originating from the left aortic sinus superiorly and anteriorly to the ostium of the left anterior descending artery, coursing downward and rightward between the aortic root posteriorly and the pulmonary trunk anteriorly, then dividing in the right coronary artery (directed into the anterior atrioventricular groove) and the left circumflex artery (turning with a retroaortic course towards the left lateral wall of the left ventricle) (Figure 5).

The awareness of the “interarterial” course prompted a discussion about further options for managing the coronary anomaly. Nevertheless, the patient refused the surgical solution and, on medical therapy, is free of symptoms after 10 months’ follow up.

Discussion. The abnormal origins of the right coronaryartery from the left sinus of Valsalva and of the left circumflex artery from the right coronary artery are two distinct congenital coronary anomalies, each providing different clinical relevance. The former accounts for 6–27% of all congenital coronary anomalies, and is potentially malignant because it is associated with a significant risk of adverse cardiac events (sudden death, myocardial infarction and angina pectoris), even in the absence of coronary atherosclerosis.6 The latter is the most frequent of all major congenital coronary anomalies, and is generally considered of no clinical significance. In our patient, both congenital abnormalities were concomitantly present, a previously unreported association, not included in any classification of congenital coronary anomalies. In addition to its academic interest, the awareness of this anomaly is important because of the large area of supplied myocardium and applied relevance in patients undergoing coronary angioplasty or cardiac surgery. The 3-dimensional course of a coronary anomaly is difficult to delineate by angiography, but a number of noninvasive diagnostic modalities may be helpful.3 In our case, MSCT confirmed the abnormal origin of the vessel from the left sinus of Valsalva and also showed its further course between the aorta and the pulmonary artery. This anatomical arrangement is potentially harmful, particularly in young athletes,4 because it is amenable to produce myocardial ischemia.7 On the other hand, typical atherosclerotic lesions may also develop in congenital coronary anomalies, as our case confirms. A few studies have even suggested a predilection of these vessels for accelerated atherosclerosis.8,9

The interventional approach to the treatment of a diseased anomalous coronary artery is technically difficult because of the slit-like configuration of the ostium and the acute angle of takeoff of the vessel.10 An additional challenge presented by our case was the extensive myocardial area at risk. Proper selection of a guiding catheter is an essential key to successful coronary angioplasty, and various techniques of approach to an anomalous right coronary artery have been proposed.10–13

Conclusion. We report a previously undescribed congenital coronary anomaly whose spatial arrangement was clearly depicted by MSCT, and underscore the technical difficulties in the percutaneous treatment of an associated atherosclerotic coronary lesion. Acknowledgement. The authors wish to thank Dr. Vitaliano Buffa for his contribution during the acquisition and interpretation of the MSCT images.

 

References

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