TIM   To investigate the differences in clinical features, angiographic characteristics and haemodynamics in patients with coronary artery aneurysm (CAA) and coronary artery ectasia (CAE), and the value of computational fluid dynamics (CFD) in the clinical treatment of patients with coronary dilatation.

  METHODS   A total of 22,456 consecutive coronary angiograms and sets of patients’ clinical characteristics were reviewed. SimVascular, a computational fluid dynamics software package, was used to analyse the haemodynamic changes in the dilated coronary artery and assist in the clinical treatment of patients with coronary dilatation.

  RESULTS  The prevalence of aneurysms and ectasia was 1.25% overall,. Compared with the CAA group, the proportion of men in the CAE group was higher (P<0.01), the age was younger (P<0.01), and the proportion of smoking patients was less (P<0.05). The location of dilatation at the coronary arteries significantly differed between CAA group and CAE group (P<0.01), with more CAAs co-existing with significant stenosis (P<0.01). The time-averaged wall shear stress (TAWSS) was markedly decreased while the oscillatory shear index (OSI) was markedly increased in CAA lesions. As the degree of CAA increased, the variance in OSI and TAWSS was apparent and vortexes emerged within the aneurysms. Changes in aneurysm shape from fusiform to spherical disturbed blood flow, with more prominent transformation of TAWSS and OSI at the beginning of CAA. Based on our hydrodynamic analysis, 10 patients with dilated coronary arteries were exempted from treatment. Two years later, 6 of them were in stable condition with no adverse events, 3 lost to follow up, and 1 died of unknown cause.

  CONCLUSION  There are significant differences in angiographic characteristics and haemodynamics between CAAs and CAEs, with CAAs more closely resembling atherosclerotic disease and CAEs less related to coronary atherosclerotic heart disease.