The fluid dynamic principles and practices show that the most kinetic dynamics is the area at the location of turbulence flow, where the antegrade flow collides with the retrograde flow. Similarly, in the coronary system, in young people, at the chaotic site, turbulent flow damages the intima. In people with vulnerable lesions, turbulent flow could weaken the cap of plaque and trigger acute coronary syndrome. Furthermore, in patients with stent, the turbulent flow is the detrimental factor of in-stent restenosis (ISR). How does the effect of reversing turbulent flow prevent ISR?

Nineteen patients with ST-Segment elevation myocardial infarction (STEMI) were continuously enrolled and followed up for six months in order to evaluate the detrimental effect of turbulent flow. All patients underwent the new dynamic angiography. At first, the coronary artery was filled with contrast, then the blood (in white color) moved in and replaced the contrast (in black color). All the process was recorded and reviewed at 15 frames/second. At the same time, the Artificial Intelligence program was developed based on an independent dataset of (226 angiograms) to recognize and detect the stenotic area. The U-net combined DenseNet121 was applied. Moreover, the second model was developed to detect and calculate the frame with stagnant contrast for predicting the local in-stent restenosis. Furthermore, Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT) has used to check the effectiveness of the stent’s implementation and flow redistribution.

Twenty-one stents were performed in nineteen patients. Ninety percent of lesions matched with turbulent flow. Right after stenting, the flow was transformed to laminar flow. Almost all stents were well implanted as confirmed by IVUS and OCT. Only one case had coronary dissection. After six months of follow-up, quantitative coronary analysis (QCA) and AI program showed that 10,5% of patients had ISR of non-significant severity and have no chest pain, shortness of breath. All patients had no collision with the retrograde against the anterograde flow. One patient (~5%) was admitted for ACS and three more stents were implanted. This patient had no ISR.

The chaos of blood (fluid) in the turbulent flow created more kinetics than laminar flow. This was seen as the mechanism of damage to the intima triggering the atherosclerotic process. Hence, the transformation of coronary flow from turbulent to laminar played a crucial role in the long-term management of CAD. This is the beginning of long-term personalized management of CAD by preventing in-stent restenosis.