BACKGROUND: Anomalous aortic origin of a coronary artery (AAOCA) from the opposite sinus of Valsalva is a rare congenital anomaly with the potential for myocardial ischemia and sudden death. This review evaluated our series of AAOCA patients, who underwent coronary artery unroofing, to test our hypothesis that the intramural length of the anomalous coronary artery correlates with symptoms. METHODS: A retrospective analysis of symptoms, preoperative imaging (computed tomography and magnetic resonance imaging), intraoperative assessment, perioperative course, and follow-up were reviewed. RESULTS: From 2005 to 2010, 27 patients (70% male) underwent surgical AAOCA repair. Mean age was 14.3 +/- 12 (range, 6 to 52) years. In 25 patients with right AAOCA, 14 had chest pain and 4 had syncope. Both patients with left AAOCA had chest pain. AAOCA unroofing was done in 25 and side-to-side anastomosis in 2. The intramural coronary artery length measured intraoperatively correlated with preoperative symptoms (symptoms = 10 +/- 3.58 mm, no symptoms = 5.2 +/- 1.5 mm, p < .002), as did preoperative imaging measurements (symptoms = 7.8 +/- 2.8 mm, no symptoms = 5.3 +/- 0.8 mm, p < .001). Preoperative imaging strongly predicted the intraoperative measurement (r = 0.81, p = 0.00001). There were no deaths, significant morbidity, or recurrence of symptoms. CONCLUSIONS: Coronary unroofing for AAOCA is a safe method of enlarging the coronary orifice and eliminating the intramural course. Symptomatic patients had a longer intramural course than asymptomatic patients, as assessed by preoperative imaging and intraoperative measurements. These results may have important clinical implications in determining indications for operation.