Author + information
- Received September 10, 2014
- Revision received December 19, 2014
- Accepted December 24, 2014
- Published online May 1, 2015.
- Yonathan F. Melman, MD, PhD,
- Donald E. Cutlip, MD and
- Saumya Das, MD, PhD∗ ()
- ↵∗Reprint requests and correspondence:
Dr. Saumya Das, Cardiovascular Division, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, CLS 907, Boston, Massachusetts 02215.
A 54-year-old woman with a medical history notable for obesity and hypertension was referred to our institution after a positive nuclear stress test. She had reported several weeks of gradually worsening chest pressure and exertional dyspnea with recent difficulty performing even activities of daily living. She underwent treadmill stress testing with nuclear imaging. She exercised to 10.1 METS and reproduced her exertional symptoms. Ischemic electrocardiographic changes were noted, and on nuclear imaging, there was a moderate-sized, reversible anteroseptal defect (Figure 1).
The patient underwent coronary angiography (Figure 2), which demonstrated the presence of a single coronary artery, arising from the right coronary cusp. The artery followed the course of the right coronary artery, and after giving off the posterior descending artery, continued in the atrioventricular groove to supply the posterior, lateral, and finally the anterior walls of the left ventricle, terminating in a small left anterior descending coronary artery (LAD) branch. A second conus branch arose near the ostium of the artery and supplied the proximal LAD territory. Coronary computed tomography (Figure 3) demonstrated the presence of the single coronary artery and conus branch; neither had an intramyocardial course nor any extrinsic compression by the aortic or pulmonic roots.
The anteroseptal ischemia was likely due to inadequate perfusion by the diminutive LAD at the terminal course of the right coronary artery, despite the absence of obstructive coronary artery disease. Her angina was medically managed with beta-blockers and nitrates with improvement in her functional capacity to the point that she was angina-free most of the day. Repeat stress testing was performed; the test was stopped at 10 min on a Bruce protocol, with the patient reporting fatigue, but no angina. Myocardial perfusion imaging (Figure 4) showed normal perfusion.
Single coronary arteries are relatively rare abnormalities, with an overall incidence of 0.04% to 0.13%. There are many anatomic variations of single coronary arteries. The first systematic classification of the variants was by Lipton et al. (1), and subsequently further elaborated by Shirani and Roberts (2). The presence of a single right coronary that supplies the entire left coronary artery is rarer still. In a series of 50,000 angiography reports retrospectively reviewed from a single center in Belgium, the incidence of single coronary arteries was 0.066%. None of them had the specific variant we found (3). In a larger series from the Cleveland Clinic of over 125,000 patients, only 1 case of such an anomaly was found (4).
The clinical course of single coronary abnormality is thought to be largely benign, and most are found at autopsy. Depending on the anatomy, however, complications ranging from stable angina to sudden cardiac death have been reported (5). Our patient’s particular anomaly, of a rare single right coronary artery supplying the entire heart, has been reported to have clinical consequences in only 2 case reports. In one, it was responsible for a stable anginal pattern with ischemia in a similar distribution to our patient (6). The other was the autopsy report of a prominent basketball player (Pete Maravich) who died suddenly while playing basketball at age 40 years. He had evidence of a chronic subendocardial infarction in the distribution of the LAD. It is likely that both Mr. Maravich and our patient experienced ischemia in a watershed distribution, distal to their relatively small anterior descending arteries (7). By treating our patient with nitrates, and presumably by lowering her filling pressures, we were able to improve diastolic coronary blood flow to the otherwise poorly perfused anteroseptum. Other causes of angina such as coronary vasospasm are probably less likely to be causative in her case, given the lack of ST-segment elevation while having chest pain. To our knowledge, this is the first published case of documented improvement by perfusion imaging of watershed ischemia as a result of anomalous coronary artery circulation.
Dr. Cutlip has received grant support from Medtronic and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received September 10, 2014.
- Revision received December 19, 2014.
- Accepted December 24, 2014.
- American College of Cardiology Foundation
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