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.

Myocardial infarction with non-obstructive disease and anomalous coronary origin: look for the common in the uncommon

Management of congenital coronary artery anomalies (CAA) is not standardized due to the variety of conditions included and their rare prevalence. Detection of CAA during myocardial infarction with non-obstructive coronary arteries (MINOCA) may induce clinicians to address the patient for surgery as CAA is not included in any algorithm^1,2 for the management of MINOCA and American Association for Thoracic Surgery evidence-based guidelines suggest surgical repair for patients with anomalous aortic origin of a coronary artery and symptoms compatible with myocardial ischaemia.³ We present the case of a 35-year-old man with an anomalous origin of left coronary artery from right Valsalva sinus with pre-pulmonic course detected during urgent coronary angiography for suspected myocardial infarction. Stress cardiac magnetic resonance did not show signs of ischaemia at high-dose dobutamine but did reveal a recent myocarditis. This clinical case highlights the need for accurate risk stratification in CAA especially when confounding clinical scenarios co-exist.