The search for the Holy Grail: Risk stratification in anomalous aortic origin of a coronary artery

Ischemia in Anomalous Aortic Origin of a Right Coronary Artery: Large Pediatric Cohort Medium-Term Outcomes

BACKGROUND

Anomalous aortic origin of a right coronary artery may cause myocardial ischemia and sudden death in the young. Data on myocardial ischemia or longitudinal outcomes are sparse in pediatric anomalous aortic origin of a right coronary artery population.

METHODS

Patients <21 years with anomalous aortic origin of a right coronary artery were prospectively enrolled. Computerized tomography angiography defined morphology. Exercise stress test and stress perfusion imaging (sPI) were performed if >7 years or younger with concern for ischemia. High-risk features included intramural length, slit-like/hypoplastic ostium, exertional symptoms, or evidence of ischemia.

RESULTS

A total of 220 patients (60% males) were enrolled December 2012 to April 2020 at a median age 11.4 years (interquartile range, 6.1-14.5), including 168 (76%) with no/nonexertional symptoms (group 1) and 52 (24%) with exertional chest pain/syncope (group 2). Computerized tomography angiography was available in 189/220 (86%), exercise stress test in 164/220 (75%), and sPI in 169/220 (77%). Exercise stress test was positive in 2/164 (1.2%) patients in group 1, both had positive sPI. Inducible ischemia (sPI) was detected in 11/120 (9%) in group 1 and 9/49 (18%) in group 2 (P=0.09). Intramural length was similar in patients with/without ischemia (5 [interquartile range, 4-7] versus 5 [interquartile range, 4-7] mm; P=0.65). Surgery was recommended in 56/220 (26%) patients with high-risk features. In 52 surgical patients (38 unroofing, 14 reimplantation), all subjects were alive and have returned to exercise at last median follow-up of 4.6 (interquartile range, 2.3-6.5) years.

CONCLUSIONS

Anomalous aortic origin of a right coronary artery patients can present with inducible ischemia on sPI despite symptoms or intramural length. Exercise stress test is a poor predictor of ischemia and caution should be given to determine low-risk based solely on this assessment. All patients are alive at medium-term follow-up.

Computed tomography angiography (CTA) of anomalous aortic origin of a coronary artery (AAOCA): Which measurements are accurate and reliable?

BACKGROUND

The variation and accuracy of computed tomography angiography (CTA) features of anomalous aortic origin of a coronary artery (AAOCA) have not been completely characterized. We evaluated anomalous right (AAORCA) and left (AAOLCA) coronary arteries by CTA, with an emphasis on reproducibility, comparison with surgical measurements, and effect of nitroglycerin.

METHODS

CTAs were interpreted for location of coronary origin & exit from the aorta, course, and dominance; minor & major diameters of the proximal & distal coronaries; shape of orifice; and intramural length. Relationships between vessel measurements, body surface area (BSA), and nitroglycerin use were evaluated. Comparisons between CTA and surgical measurements included intramural length, surgical probe size pre-intervention vs. CTA proximal AAOCA diameter, and surgical probe size post-intervention vs. CTA distal AAOCA diameter.

RESULTS

Of 104 patients [81 (78%) AAORCA], all but 1 were intramural. Compared to AAOLCA, AAORCA patients were more likely to have a high origin (91% vs. 31%, p ​< ​0.01), and slit-like orifice (58% vs. 26%, p ​< ​0.01). When CTAs with nitroglycerin were compared to those without, no difference in proximal AAOCA dimensions was identified; however distal AAOCA and normal-origin coronary dimensions were larger in scans with nitroglycerin. Aside from slit-like orifice, reliability of coronary CTA measurements, including proximal AAOCA minor diameter and intramural length, was moderate to good between readers. In a subgroup of 54 patients, proximal AAOCA minor diameter and intramural length had good agreement and correlation with surgery.

CONCLUSION

Proximal AAOCA dimensions and intramural length are reproducible variables. The lack of difference in proximal AAOCA dimensions with nitroglycerin may reflect abnormal vessel mechanics. Multicenter studies are an important next step in understanding the generalizability of our findings.

Flow Dynamics in Anomalous Aortic Origin of a Coronary Artery in Children: Importance of the Intramural Segment

This study aims to assess the differences in pressure, fractional flow reserve (FFR) and coronary flow (with increasing pressure) of the proximal coronary artery in patients with anomalous aortic origin of a coronary artery with a confirmed ischemic event, without ischemic events, and before and after unroofing surgery, and compare to a patient with normal coronary arteries. Patient-specific flow models were 3D printed for 3 subjects with anomalous right coronary arteries with intramural course, 2 of them had documented ischemia, and compared with a patient with normal coronaries. The models were placed in the aortic position of a pulse duplicator and precise measurements to quantify FFR and coronary flow rate were performed from the aortic to the mediastinal segment of the anomalous right coronary artery. In an ischemic model, a gradual FFR drop (emulating that of pressure) was shown from the ostium location (∼1.0) to the distal intramural course (0.48). In nonischemic and normal patient models, FFR for all locations did not drop below 0.9. In a second ischemic model prior to repair, a drop to 0.44 was encountered at the intramural and mediastinal intersection, improving to 0.86 postrepair. There is a difference in instantaneous coronary flow rate with increasing aortic pressure in the ischemic models (slope 0.2846), compared to the postrepair and normal models (slope >0.53). These observations on patient models support a biomechanical basis for ischemia and potentially sudden cardiac death in aortic origin of a coronary artery, with a drop in pressure and FFR in the intramural segment, and a decrease in coronary flow rate with increasing aortic pressure, with both improving after corrective surgery.

Management and Anesthetic Considerations for Patients With Anomalous Aortic Origin of a Coronary Artery

The term "coronary artery anomalies" encompasses a large and heterogeneous group of disorders that may affect origin, intrinsic anatomy, course, location, and termination of the coronary arteries. With these different anatomies, presentation, symptoms, and outcomes are heterogeneous as well. While significant efforts are directed toward improving diagnosis and risk-stratification, best evidence-guided practices remain in evolution. Data about anesthetic management of patients with coronary anomalies are lacking as well. This review aims to provide the anesthesiologist with a better understanding of an important subgroup of coronary artery anomalies: anomalous aortic origin of a coronary artery. We will discuss classification, pathophysiology, incidence, evaluation, management, and anesthetic implications of this potentially fatal disease group.