Computed tomographic-based three-dimensional printing of giant coronary artery fistulas to guide surgical strategy: a case series.

Background: Coronary artery fistulas (CAFs) are abnormal communications between the coronary arteries and the heart chambers, arteries, or veins, potentially leading to significant shunting, myocardial ischaemia and heart failure. Computed tomographic (CT) angiography or conventional invasive angiography is the reference standard for the diagnosis of coronary fistulas. The fistula anatomy can become very complex, which makes surgical or interventional planning challenging. Case summary: We report two cases of hugely dilated and tortuous coronary circumflex artery fistulas draining into the coronary sinus. Both patients were followed up for more than 10 years because of very complex coronary fistula anatomy and mild symptoms. From two-dimensional (2D) sliced CT images alone it, was uncertain whether surgery was feasible. However, since both patients had symptom progression (Patient 1 developed heart failure, and Patient 2 had recurrent pericardial effusions), three-dimensional (3D) heart models were printed for better understanding of the complex fistula anatomy and improved surgical planning. Both patients had successful surgery and symptomatic relief at follow-up. Discussion: The delay in surgery, until clinical deterioration, may partly be a consequence of a general reluctance in performing complex surgery in patients with CAFs. As of now, CT-based 3D printing has primarily been used in isolated cases. However, 3D printing is evolving rapidly and supplementing 2D sliced CT images with a physical 3D heart model may improve the anatomical understanding and pre-surgical planning that could lead to better surgical outcome.