A Rare Variant of a Single Coronary Ostium Arising From the Right Sinus of Valsalva

Abstract

A single coronary ostium originating from the right sinus of Valsalva and giving rise to the left anterior descending artery (LAD), right coronary artery (RCA), and left circumflex artery (LCX) is a rare variant of coronary artery anatomy. Here, we present a case of a coronary artery anomaly found on CT coronary angiography in a patient presenting with substernal chest pain. Although abnormal, the anatomy presented in this case was found to be a nonmalignant variant, as the vessels do not pass between other muscular arteries in an inter-arterial fashion. Due to the benign nature of this anatomical variant, the patient was treated for coronary artery disease and managed medically.  

The larger coronary arteries and their anatomy are grossly preserved across our species. Yet no two individual’s coronary anatomies are exactly the same. While the architecture of our coronary vasculature begins with roughly the same design, throughout development, the diverse physiological demands of the individual promotes a unique expression of a predetermined plan. This results in a spectrum of normal. 

Whereas normal deviations in coronary anatomy arise throughout life and are found at the level of the microvasculature, coronary artery anomalies (CAAs) are deviations in the larger coronary ostia that are present at birth. The incidence of CAAs was found to be approximately 1-5% in the adult population undergoing coronary artery angiography.^1,2 CAAs are diverse and present with varying frequency. Up to 80% of CAAs are benign and follow an asymptomatic course, only making themselves known when separate underlying disease processes require further investigation.³ Herein, we present a case of a single ostium originating from the right sinus of Valsalva, giving rise to a right coronary artery (RCA), as well as an anomalous left anterior descending coronary artery (LAD) and left circumflex artery (LCX), confirmed by coronary angiography and CTA study.  

Case report

A 67-year-old female presented to the Heart and Vascular Institute of Florida with complaints of substernal chest pain and bilateral lower extremity pain. She reported that the chest pain lasted for greater than 30 minutes in duration and was provoked with exertion and/or emotional stress. Her past medical history was significant for angina, claudication, peripheral vascular disease, hypertension, and hypercholesterolemia.

Two months prior to this visit, pharmacological cardiac stress testing showed abnormal myocardial perfusion with areas of moderate ischemia in the basal and mid-anteroseptal myocardial walls. Upon administration of intravenous Lexiscan (regadenoson), her heart rate rose from a baseline of 71 to 109 beats per minute, corresponding with 71% of the maximum predicted heart rate. During the stress procedure, the patient did not develop symptoms, but her blood pressure response was hypertensive, rising from 137/62 mmHg to 159/79 mmHg. As follow-up, the patient was sent for coronary angiography and left heart catheterization to further assess her heart function and coronary anatomy. Coronary angiography revealed anomalous coronary anatomy with the RCA, LAD, and LCX all originating from a single ostium arising from the right coronary cusp.

In order to more accurately evaluate this patient’s anomalous coronary vasculature, CT coronary angiography with contrast was performed (Figure 1). Throughout the level of the heart, 0.625 mm axial images were obtained with subsequent 3D post processing multi-planar reconstructions of the coronary arteries (Figure 2). The results of the CTA revealed right dominance with all coronary vessels arising from the right coronary sinus. An anomalous left main was seen to arise from the right coronary sinus and rapidly enter the posterior wall of the right ventricular outflow track and upper intraventricular septum before exiting into the upper atrioventricular groove (Figure 3). Although abnormal, this course is considered to be a nonmalignant variant, as the vessels do not pass between other muscular arteries in an inter-arterial fashion. Instead, the vessels course intramurally within the myocardium with no evidence of extrinsic compression or acute angulations. The RCA showed no abnormalities and followed a normal course.

Discussion

CAAs arising from a single ostium are extremely rare, occurring in only 0.024% to 0.066% in the general population undergoing coronary angiography.⁴ Herein, we presented a case where all three of the primary coronary arteries arose to form a single ostium that originated from the right coronary sinus of Valsalva. This abnormality has an incidence of less than .017%.

This so-called ectopic origin of the left coronary artery from the right sinus of Valsalva has five variants. Classification of the variants is based on the relationship between the anomalous artery and the great vessels. The five subtypes are designated as anterior, posterior, between, septal, and combined (Table 1). The aforementioned anomaly is a member of the septal variant that is often benign.^1,5,6 

Cardiac catheterization is considered to be the gold standard for diagnosis of CAAs, although transthoracic echocardiogram (TTE) can also be useful in diagnosis if special attention is placed on the origin of the coronary arteries.^7,8 Traditionally, magnetic resonance angiography (MRA) and computed tomography angiography (CTA) have been the noninvasive imaging modalities of choice to define the course of the anomalous vessels. Recent studies have shown that multidetector row-computed tomography (MDCT) is a new, noninvasive imaging technique that has excellent spatial resolution for detecting the origin and course of anomalous coronary vessels, providing greater resolution of distal vessels than MRA imaging.⁷ 

Treatment decisions for patients with CAAs should be guided largely by whether the patient is symptomatic or asymptomatic. Preventing sudden cardiac death, a feared complication of CAAs, is the main goal of treatment for symptomatic patients or those who have evidence of exercise-induced myocardial ischemia. Three treatment options currently exist for patients suffering from symptoms secondary to a CAA: medical treatment/observation, coronary angioplasty with stent deployment, and surgical correction.1 Beta-blockers, diuretics, antiarrhythmic drugs, and oxygen therapy can help to alleviate mild to moderate symptoms and decrease the risk of sudden cardiac death in these patients. 

More advanced treatment strategies may need to be employed in higher risk patients. Stent-angioplasty is often reserved for more advanced cases of CAAs and may be indicated if the patient is suffering from disabling symptoms, has an area of vessel stenosis greater than 50% when compared to the distal normal vessel, has a large myocardial territory dependent on blood flow from the anomalous vessel, or has reversible ischemia.¹ If a significant territory of the heart is at risk due to compromised blood flow through the anomalous vessel, surgery may be indicated. Surgical correction may consist of direct re-implantation of the anomalous artery to its correct anatomical location, coronary artery bypass grafting (CABG), unroofing of the intramural vessel segment, or osteoplasty, whereby a new ostium is created at the end of the anomalous artery’s intramural course.^2,9-12

Conclusion

Congenital anomalies of the coronary vasculature comprise a diverse group of abnormalities, thus creating a large set of potential pathophysiologic mechanisms of disease. As a result, anomalies must be evaluated individually by experts that have been trained specifically in the intricacies of the disease mechanisms and manifestations of CAAs. However, due to the rarity of these cases, it becomes nearly impossible for experts to arise without close collaboration within the cardiology community. In order to further this goal, we presented herein our case of a 67-year-old female with a nearly unique anomaly. We are proposing to name the anomaly “The Siddiqui Anomaly”.

References

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​^aCollege of Medicine, University of Central Florida, Orlando, Florida; ^bChief of Cardiology and Director of Cardiac Catheterization Lab, Heart & Vascular Institute of Florida, Davenport, Florida

This article received a double-blind peer review from members of the Cath Lab Digest Editorial Board.

The authors can be contacted via Dr. Irfan Siddiqui at drsiddiqui@myheartdoc.org.