Coronary artery fistula in adults: Incidence and appearance on cardiac computed tomography and comparison of detectability and hemodynamic effects with those on transthoracic echocardiography.

Background: The widespread use of cardiac computed tomography (CT) has increased the incidental discovery of fistulas of the coronary artery (CAF). This condition is rare and can affect hemodynamic parameters, but few reports focus on its hemodynamic effects. We investigated the frequency and types of CAF on CT and compared them with those of transthoracic echocardiography (TTE) to evaluate the detectability of CAF and its hemodynamic effects.
Materials and Methods: We retrospectively evaluated cardiac CT images of 6789 adult patients who underwent imaging from January 1, 2013 through September 30, 2019 at our institution. We assessed the CT images for the presence of CAF and compared our findings with those obtained by TTE in control cases without CAF.
Results: The prevalence of CAF determined with cardiac CT was 0.91%, with the left anterior descending artery (67.7%) as the most common site of origin and the main pulmonary artery (82.3%) as the most common origin of drainage. The incidence of aneurysm accompanying CAF was 48.4%. Color Doppler in TTE demonstrated abnormal flow that would suggest the presence of CAF of only 23.1%. Echocardiographic findings of hemodynamics did not differ significantly between patients with and without CAF nor between elderly and non-elderly patients with CAF.
Conclusions: Our study revealed differing prevalence and types of CAF from those reported using coronary angiography and little impact of CAF on hemodynamics. Color Doppler in TTE did not readily depict abnormal flow that might suggest the presence of a fistula, but cardiac CT allowed noninvasive and comprehensive assessment of CAF. Thus, we believe the acquisition of cardiac CT is necessary to establish the cause of continuous murmur that is not identified with TTE.
(Copyright © 2020. Published by Elsevier Ltd.)