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

Authors

Hoda Hatoum
Rajesh Krishnamurthy
Jayanthi Parthasarathy
Dorma C Flemister
Carly M Krull
Benjamin A Walter
Carlos M Mery
Silvana Molossi
Lakshmi Prasad Dasi

Publication Date

1-1-2022

Journal

Seminars in Thoracic and Cardiovascular Surgery

DOI

10.1053/j.semtcvs.2020.11.027

PMID

33242612

PMCID

PMC11062399

PubMedCentral® Posted Date

5-1-2024

PubMedCentral® Full Text Version

Author MSS

Published Open-Access

yes

Keywords

Aorta, Child, Coronary Vessel Anomalies, Coronary Vessels, Fractional Flow Reserve, Myocardial, Humans, Treatment Outcome

Abstract

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.