Prognosis of Intramural Coronary Arteries

Study Questions:

What is the prognosis of an intramural coronary artery identified on coronary computed tomography angiography (CCTA)?

Methods:

This study examined 947 patients referred for CCTA and without obstructive coronary artery disease (CAD). The prevalence and characteristics of an intramural course were evaluated, and the prognosis (unstable angina, myocardial infarction, mortality) was compared between patients with and without an intramural course.

Results:

An intramural course was observed in 22% (210/947) of individuals. The median depth was 1.9 mm, and 40% of patients had a depth ≥2 mm within the myocardium. These were most commonly observed in the left anterior descending artery territory (47%) or left circumflex artery territory (52%). Over a median follow-up of 4.9 years, 43 events occurred. There were no differences in outcomes between patients with versus without an intramural course in unstable angina (1.0 vs. 1.5%, p = 0.64), myocardial infarction (1.0 vs. 0.7%, p = 0.57), mortality (1.9 vs. 2.6%, p = 0.69), or the combined endpoint (3.8 vs. 4.7%, p = 0.73).

Conclusions:

An intramural coronary artery course is commonly identified on CCTA in patients without obstructive CAD, and is not associated with a difference in adverse events during an intermediate-term follow-up.

Perspective:

CCTA identifies anatomic details that may not be seen on other cardiovascular tests, and the frequent identification of an intramural coronary artery is one example of this. Only cases with significant constriction of the arterial lumen by the myocardium are appreciated on invasive coronary angiography, while CCTA can easily visualize any coronary artery that lives within the myocardium. This study finds that these are very common in patients without obstructive CAD, and that their presence is not associated with any difference in intermediate-term adverse events. This study was retrospective, and it is unknown if it was adequately powered to detect a difference in adverse events. Further, it was not able to compare outcomes between subgroups that could be at potentially higher risk (e.g., deeper or longer course, significant systolic compression of the lumen). As there are case reports of adverse events in patients with an intramural coronary artery course, these findings should be evaluated in the context of the individual patient. Nevertheless, this large study is reassuring that intramural coronary arteries detected on CCTA and in the absence of obstructive CAD are associated with a favorable intermediate-term prognosis.

Clinical Topics: Acute Coronary Syndromes, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging

Keywords: Acute Coronary Syndrome, Angina, Unstable, Cardiac Imaging Techniques, Coronary Angiography, Coronary Artery Disease, Myocardial Infarction, Myocardial Ischemia, Myocardium, Prognosis, Tomography, X-Ray Computed, Tomography


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