Anomalous aortic origin of a coronary artery (AAOCA) is the second leading cause of sudden cardiac death in young athletes, with a prevalence of 0.1%-0.7% in the general population. This figure likely underestimates the actual prevalence, as routine screening tests are not typically performed without clinical indications. AAOCA may involve both the left (AAOLCA) and right coronary artery (AAORCA) origins. It can also affect the coronary artery’s course, which may be prepulmonary, interarterial, subpulmonary, retroaortic, intraseptal, or retrocardiac. Right coronary involvement is 3-6 times more frequent than left coronary involvement; however, AAOLCA carries a higher risk of sudden cardiac death, particularly during or immediately after exercise. Furthermore, certain anatomical variants increase the risk of ischemia and sudden death. High-risk anatomies include a slit-like orifice, interarterial course, intramural course, acute take-off angle, high origin, and proximal stenosis due to an elliptical vessel shape.
The team led by Dearani et al. at Mayo Clinic reported outcomes of the unroofing technique in 148 patients with intramural AAOCA from 2003 to 2020. Patients with intraseptal AAOCA or anomalous left anterior descending artery originating from the right sinus and crossing the right ventricular outflow tract were excluded. The article provides a brief overview of their preoperative and postoperative study protocol, which utilized echocardiography, coronary computed tomography angiography (CTA), catheterization (in adults with risk factors), stress echocardiography, or nuclear medicine testing. They also describe a standardized surgical technique.
The study included 130 patients with AAORCA and 18 with AAOLCA, with a median age of 44 years. In 80% of cases, the anomaly was corrected as an isolated procedure, yielding an in-hospital mortality of <1% (2 deaths, both adults >55 years with postoperative complications following reoperations for aortic root or valve replacement associated with AAOCA repair). Commissural resuspension of the aortic valve was required in 25 cases to achieve adequate unroofing. No cases of iatrogenic worsening of aortic valve function were observed. Over a median follow-up of 9.5 years, 5 deaths were reported—3 from non-cardiovascular causes and 2 from unknown causes. No pediatric patients (n = 29) died during the postoperative period or follow-up. Post-repair survival for AAOCA was 94.5% at 15 years. Clinical follow-up data were available for nearly 75% of the cohort. During a median follow-up of 3.9 years, approximately one-third of patients reported chest pain; however, ischemia screening revealed no correlation between chest pain and the unroofed coronary artery.
No dysfunction of native aortic valves was observed in patients undergoing unroofing as an isolated procedure for anomalous coronary arteries.
The authors concluded that unroofing of intramural AAOCA is a safe technique with low postoperative mortality, even when performed alongside concomitant procedures in previously operated patients. Long-term survival is excellent, with most patients asymptomatic and resuming their lives without limitations.
COMMENTARY:
The 2020 ESC guidelines on congenital heart diseases in adults recommend surgery in symptomatic AAOCA patients with evidence of ischemia in the corresponding territory or high-risk anatomies. Surgery is also recommended for asymptomatic AAOLCA patients with myocardial ischemia or high-risk anatomy. Surgery is discouraged in asymptomatic AAORCA patients without evidence of myocardial ischemia or high-risk anatomy. Traditionally, AAOLCA is considered high risk due to its strong association with sudden cardiac death. However, Jegatheeswaran et al. from the Toronto group demonstrated in a multicenter study that AAORCA accounted for one-third of sudden cardiac deaths related to AAOCA, indicating it should not be considered benign. In fact, in their study, 3 of the 4 pre-hospital cardiorespiratory arrests related to AAOCA involved anomalous right coronary arteries.
The goal of surgery is to address four potential mechanisms of ischemia: 1) slit-like orifice geometry and dynamic stenosis causing pressure loss and turbulent flow; 2) systolic collapse of the thin-walled intramural segment; 3) systolic stretching of the aortic wall at the intramural segment; and 4) extrinsic compression of the interarterial segment between the aorta and pulmonary artery.
This study focused on the unroofing technique, but other approaches not discussed in the article include coronary reimplantation, pulmonary artery translocation, and, as a last resort, coronary artery bypass grafting (CABG). CABG should only be employed when fixed stenosis >50% is present in the anomalous vessel. Otherwise, there is a high risk of early graft failure due to competitive flow, as coronary perfusion impairment in AAOCA is often phasic and physiologically specific, unlike atherosclerotic disease.
The Mayo Clinic’s algorithm closely resembles protocols published by other institutions, emphasizing imaging studies and ischemia-provoking tests. This is particularly important for identifying asymptomatic patients post-surgery. Relying solely on the absence of contractility abnormalities during echocardiographic follow-up may lead to false negatives, as these lesions are dynamic. The appropriate screening test remains contentious. Some groups use dobutamine stress echocardiography, nuclear medicine tests, cardiac functional MRI, or, in rare cases, catheterization with fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR). However, no validated data exist for dynamic stenoses. In light of this variability, future efforts should aim to standardize diagnostic procedures and align clinical findings with patient outcomes.
Despite being an insightful study with a large cohort for this rare pathology, several limitations must be acknowledged. The data are retrospective from a single center, potentially limiting generalizability. Clinical follow-up was unavailable for nearly 25% of patients, and the median follow-up period of 3.9 years may underestimate ischemia incidence.
In conclusion, this study provides three key takeaways: unroofing surgery has low short- and long-term mortality; outcomes in pediatric populations are particularly favorable; and AAORCA should not be considered benign.
REFERENCE:
Patlolla S, Stephens E, Schaff H, Anavekar N, Miranda W, Julsrud P, et al. Outcomes of a protocolized approach for surgical unroofing of intramural anomalous aortic origin of coronary artery in children and adults. J Thorac Cardiovasc Surg. 2022 Dec. doi: 10.1016/j.jtcvs.2022.11.037
