Response to Letter Regarding Article, “Long-Term Outcome and Impact of Surgery on Adults With Coronary Arteries Originating From the Opposite Coronary Cusp”

Abstract

We appreciate Dr Angelini's insights. The prevalence of anomalous coronary artery from the opposite sinus of Valsalva (ACAOS) that he reports from our article, however, was ACAOS with interarterial course (IAC). The actual prevalence of ACAOS was 0.14% (301 cases in 210 700 angiograms), 1 a number consistent with several large, recently published series. For comparison, a Turkish group found a prevalence of 0.08% (11 cases in 12 457 angiograms), 2 and recent series from India and China found prevalence to be 0.3% and 0.5%, respectively. We actually found that angiographers overreported rather than underreported this anomaly, and that only 57% of those patients initially coded as ACAOS in our registry were eventually confirmed. We agree that there are significant limitations to any epidemiological study, and that a prospective registry with strict diagnostic criteria could more precisely establish prevalence. Unfortunately, tertiary facilities like ours and Dr Angelini's now have referral bias for these lesions, significantly limiting our role in prevalence assessment.Because of its invasiveness, angiography is not ideal to screen for ACAOS. In addition, most angiography is (appropriately) performed in symptomatic patients, and may overestimate prevalence. Angiography also does not diagnose whether the course is intramural (shared intima and media of the coronary artery and the aortic wall). Coronary computed tomography scanning has proliferated in recent years, and studies are often performed to assess early atherosclerosis. A Chinese group recently found ACAOS in 0.3% patients undergoing dual-source computed tomography coronary angiography. 3 The authors only specify that the studies were "clinically indicated," and it is not known how many patients were symptomatic. A Korean group found ACAOS in 0.4% of patients undergoing coronary calcium scoring and demonstrated good interobserver agreement on diagnosis. 4 We agree with Angelini that IAC is much more likely malignant than ACAOS without IAC. We included all ACAOS patients based on prior convention and to have a comparator population for those with IAC. It is important to recognize that the left main artery originating from the right coronary sinus has 4 potential pathways, only 1 of which is between the great vessels. Computed tomography scanning has greatly facilitated the differentiation of these paths, which previously was a challenge for inexperienced angiographers. An intramural course in our experience, however, is far more difficult to establish, even with modern computed tomography scanning. Although an intramural course is considerably more likely when the coronary sinus has an interarterial course, definitive confirmation requires surgical exploration and all interarterial coronary arteries are not intramural.Atherosclerotic disease severity is an important confounder that we attempted to control for during analysis. Unfortunately, the small population size did not allow for comparison between patients with and without obstructive disease. In a coho...