BACKGROUND: This study aimed to assess postoperative presumed high-risk anatomic features (HRAFs) by using computed tomographic angiography (CTA) in patients with anomalous aortic origin of a coronary artery (AAOCA) after surgical unroofing vs transection and reimplantation (TAR) if unroofing was thought to provide unsatisfactory results. METHODS: The study included 62 children with postoperative CTA performed at a median of 3 months (interquartile range, 3-4 months) after unroofing (n = 45) and TAR (n = 17). HRAFs included slitlike ostium, intramural course, acute angle takeoff (<45o), interarterial course, proximal stenosis >50%, or course through a thickened intercoronary pillar. RESULTS: Median age at surgery was 13.8 years (interquartile range, 10.5-15.8 years). None of the patients had a slitlike ostium or an intramural course on postoperative CTA. Acute takeoff was seen in 100% after unroofing and in 2 of 17 (12%) after TAR (P < .001). After unroofing, the interarterial course improved to 35 of 45 (78%) from 43 of 45 (96%) (P = .003), and a thickened intercoronary pillar improved to 10 of 45 (22%) from 22 of 45 (49%) (P = .0001), compared with none seen after TAR. Preoperative intramural length <5 mm was associated with a postoperative thickened intercoronary pillar in right AAOCA after unroofing (P = .0004). Severe coronary stenosis occurred in 2 of 17 (12%) after TAR, and both patients needed urgent revision procedures. All patients except 2 (97%) returned to exercise activities at a median follow-up of 4.9 years (range, 0.6-9.2 years). CONCLUSIONS: The slitlike ostium and intramural course resolved in all patients. Residual acute angle takeoff, an interarterial course, and mild coronary narrowing related to a thickened intercoronary pillar were common after unroofing. TAR allows resolution of all HRAFs, although severe narrowing requiring surgical revision happened only in TAR. Long-term studies are needed to understand the clinical significance of these residual presumed HRAFs.