Lumped-parameter model as a non-invasive tool to assess coronary blood flow in AAOCA patients.

Anomalous aortic origin of the coronary artery (AAOCA) is a rare disease associated with sudden cardiac death, usually related to physical effort in young people. Clinical routine tests fail to assess the ischemic risk, calling for novel diagnostic approaches. To this aim, some recent studies propose to assess the coronary blood flow (CBF) in AAOCA by computational simulations but they are limited by the use of data from literature retrieved from normal subjects. To overcome this limitation and obtain a reliable assessment of CBF, we developed a fully patient-specific lumped parameter model based on clinical imaging and in-vivo data retrieved during invasive coronary functional assessment of subjects with AAOCA. In such a way, we can estimate the CBF replicating the two hemodynamic conditions in-vivo analyzed. The model can mimic the effective coronary behavior with high accuracy and could be a valuable tool to quantify CBF in AAOCA. It represents the first step required to move toward a future clinical application with the aim of improving patient care. The study was registered at Clinicaltrial.gov with (ID: NCT05159791, date 2021-12-16).

Morphological Changes of Anomalous Coronary Arteries From the Aorta During the Cardiac Cycle Assessed by IVUS in Resting Conditions.

BACKGROUND: Anomalous aortic origin of coronary artery (AAOCA) with intramural segment is associated with risk of sudden cardiac death, probably related to a compressive mechanism exerted by the aorta. However, the intramural compression occurrence and magnitude during the cardiac cycle remain unknown. We hypothesized that (1) in end diastole, the intramural segment is narrower, more elliptic, and has greater resistance than extramural segment; (2) the intramural segment experiences a further compression in systole; and (3) morphometry and its systolic changes vary within different lumen cross-sections of the intramural segment. METHODS: Phasic changes of lumen cross-sectional coronary area, roundness (minimum/maximum lumen diameter), and hemodynamic resistance (Poiseuille law for noncircular sections) were derived from intravascular ultrasound pullbacks at rest for the ostial, distal intramural, and extramural segments. Data were obtained for 35 AAOCA (n=23 with intramural tract) after retrospective image-based gating and manual lumen segmentation. Differences between systolic and end-diastolic phases in each section, between sections of the same coronary, and between AAOCA with and without intramural tract were assessed by nonparametric statistical tests. RESULTS: In end diastole, both the ostial and distal intramural sections were more elliptical (P<0.001) than the reference extramural section and the correspondent sections in AAOCA without intramural segment. In systole, AAOCA with intramural segment showed a flattening at the ostium (-6.76% [10.82%]; P=0.024) and a flattening (-5.36% [16.56%]; P=0.011), a narrowing (-4.62% [11.38%]; P=0.020), and a resistance increase (15.61% [30.07%]; P=0.012) at the distal intramural section. No-intramural sections did not show morphological changes during the entire cardiac cycle. CONCLUSIONS: AAOCA with intramural segment has pathological segment-specific dynamic compression mainly in the systole under resting conditions. Studying AAOCA behavior with intravascular ultrasound during the cardiac cycle may help to evaluate and quantify the severity of the narrowing.