Flow Dynamics in Anomalous Aortic Origin of a Coronary Artery in Children: Importance of the Intramural Segment.
Hatoum H, Krishnamurthy R, Parthasarathy J, Flemister DC, Krull CM, Walter BA, Mery CM, Molossi S, Dasi LP.Semin Thorac Cardiovasc Surg. 2020 Nov 23:S1043-0679(20)30422-6. doi: 10.1053/j.semtcvs.2020.11.027. Online ahead of print.PMID: 33242612
Take Home Points:
- 3D printing model helps to assess the coronary flow and fractional flow reserve in ex-vivo.
- Coronary flow and fractional flow reserve decrease in the intramural portion during the aortic pressure increases.
- This ex-vivo functional assessment enables us to stratify the risk of myocardial ischemia and sudden death, thereby may help to make a decision for surgical intervention in patients with anomalous aortic origin of right coronary artery without any symptom.
Commentary from Dr. Yasuhiro Kotani (Okayama, Japan), section editor of Congenital Heart Surgery Journal Watch: Hatoum and his colleague published the paper regarding the risk assessment of anomalous aortic origin of a coronary artery (AAOCA) in children. They used 3D printing flow models placed in the aortic position of a pulse duplicator to measure the hemodynamics in the specific anatomy in AAOCA. Main findings from this study was that pressure, fractional flow reserve (FFR), and coronary flow dropped at the site of intramural course of right coronary artery arising from left sinus when the aortic pressure increased in patient with ischemia. The model for patient who had an unroofing repair of AAOCA demonstrated the improved the coronary flow and FFR.
It is extremely difficult to stratify the risk in patients with AAOCA, especially anomalous right without any symptom, hence surgical indication is controversial. This ex-vivo model represents the unique anatomy of AAOCA and enables to functional assessment without any invasive test.
Through the clinical experience of the repair of AAOCA, we became to know its unique anatomy and function, yet still not uncertain for risk stratification in each patient because of a wide variety of anatomic characteristics, such as the location of the ostium, the length of intramural course, and the relation to the pulmonary artery. Surgery for left coronary anomaly is recommended even in asymptomatic patients, however, we are still not known which patients should undergo the surgery in anomalous right coronary without any symptoms. Stress test can help to guide us to go for the repair but does not always show positive. The unroofing procedure is relatively simple procedure that experienced congenital surgeon can perform with very low risk, but the creation of new aortic regurgitation after surgery mainly due to manipulation of the commissure is not negligible. The 3D printing patient specific model can make functional assessment possible in ex-vivo and help us to determine the surgical indication if the model demonstrates significant drop in coronary flow and FFR. As AAOCA is very rare condition, nationwide database is necessary to build the guideline in the future. As accumulation of the experience of the treatment of AAOCA, database can also help to provide the tailormade recommendation for the choice of surgical technique in each patient.