Investigating the utility of Computed Tomography Coronary Angiography in Spontaneous Coronary Artery Dissection.

Background

Spontaneous coronary artery dissection (SCAD) is an important cause of acute coronary syndromes, particularly among young women and individuals with few conventional atherosclerotic risk factors. Invasive coronary angiography (ICA) is the gold standard for the diagnosis of SCAD, although there are risks associated with ICA. Computed tomography coronary angiography (CTCA) is an emerging alternative modality to diagnose SCAD. The accuracy of CTCA for diagnosing SCAD remains unclear.

Objective

To investigate the accuracy of CTCA in acute SCAD diagnosis, and to apply novel CT technology including peri-coronary fat attenuation index (FAI)-score for the diagnosis of acute SCAD, and indices of coronary tortuosity in patients previously diagnosed with SCAD.

Methods

CTCA studies were obtained with patients consented to participate in the UK SCAD registry. The diagnostic accuracy of CTCA was assessed in 25 acute SCAD, and 25 normal scans by five independent readers. Standard FAI-score in the proximal vessel was obtained in an extended cohort. Finally, indices of coronary tortuosity were calculated in patients previously diagnosed with SCAD.

Results

CTCA showed poor sensitivity, and negative predictive value for the diagnosis of acute SCAD compared to normal scans. Secondly, using previously reported methods of tortuosity assessment, and a novel semi-automated technique we confirm previous reports that coronary tortuosity is more prevalent in SCAD compered to normal, and that tortuosity is throughout the coronary tree. Finally, standard FAI-score in the proximal vessel suggests that in large vessels the FAI-score is higher compared to SCAD. However, it has limited utility in the diagnosis of SCAD.

Conclusion

The role of standard CTCA analysis in acute SCAD seems limited. However, enhanced CTCA, using a refined FAI-score and other features, holds promise for a future non-invasive imaging strategy.