Persistent Angina Uncovers Unusual Communication Between the Left Anterior Descending and Circumflex Arteries
A 55-year-old man had presented with progressive dyspnea and chest pain on exertion. The patient underwent a treadmill stress echocardiogram which reproduced his symptoms. However, no regional wall motion abnormalities were documented and the stress test was read as negative. He had achieved 10.0 METs on the Bruce protocol (double product 25 988) and had a resting ejection fraction of 62% that improved to 80% with stress. Despite medical optimization with β blockade and long acting nitrates, the patient continued to have significant symptomatology while engaged in activities of daily living. He was referred for coronary angiography because of ongoing angina.
Angiography revealed that the left main coronary artery had a 70% stenosis and led to a diminutive left circumflex and ramus intermedius arteries. There was an arterial connection bridging from the ramus intermedius connecting to an anomalous left anterior descending artery (LAD) which filled both anterograde and retrograde (Figure 1). The ostium of the LAD could not be initially located despite extensive effort. To further characterize the coronary anatomy for planning revascularization, a contrast-enhanced CT coronary angiogram with 3-dimensional reconstruction was obtained (Movie I in the online-only Data Supplement). This confirmed the origin of the LAD from the right aortic sinus and ruled out an aortic intramural component or slit-like orifice. This artery coursed behind the right ventricular outflow tract and in the interventricular septum before reaching its perfusion territory (Figure 2).
Coronary angiography was subsequently used to reconfirm full patency of the LAD before assessing the LM stenosis with intravascular ultrasound (Movie II in the online-only Data Supplement) and fractional flow reserve. Despite the presence of collateral flow from the anomalous LAD, the fractional flow reserve of the left main coronary artery was 0.82. Intravascular ultrasound revealed minimal luminal diameter of 1.6 mm and a minimal luminal area of 2.4 mm.2 The diameter stenosis was estimated to be 72% (Figure 3, upper left and inset). A Xience 3- × 15-mm drug eluting stent was successfully deployed in the left main coronary artery (Figure 3, Movie III in the online-only Data Supplement) with complete resolution of his symptoms.
Coronary artery anomalies are rare, occurring in 0.6% to 1.3% of all patients undergoing coronary angiography, with men affected more frequently than females.1,2 A LAD originating from either the proximal right coronary artery or the right sinus of Valsalva occurs in 1% to 6% of all detected coronary anomalies, which equates to an angiographic prevalence of 1 in 10 000.2–4 Though the main driving force for PCI was ongoing angina, patients with left sided coronary artery arising from the right cusp have a 14:1 increased risk of sudden cardiac death when compared with those with right sided coronaries from the left cusp.4,5 Furthermore, correlation between exertion and sudden death is documented in this population.5,6 This patient was symptomatic, had a job that demanded significant exertion, and an LAD coming off of the right cusp. Thus it was felt that in addition to symptomatic benefit, his risk for sudden death would be reduced with correction of the left main lesion.
To our knowledge, this is the first report of an anomalous LAD originating from the right sinus with persistent communication with the native left main system via an arterial bridge connection to the ramus intermedius.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.112.135111/-/DC1.
- © 2013 American Heart Association, Inc.