부산대학교 도서관

Introduction: Many patients with acute coronary syndrome (ACS) presented with elevated troponin level and reversible changes in the thallium scan. When they patients underwent coronary angiogram, the results showed patent coronary arteries. WHY?Hypothesis: Could abnormal coronary flow explain ACS, abnormal thallium and patent coronary arteries?Methods: Patients with newly diagnosed ACS and abnormal Thallium scan underwent a new dynamic coronary angiogram. 10 patients without ACS, normal EF and no coronary artery disease served as control. In this new technique, the contrast and blood flow were recorded at 15 images per second. The first image was of the index artery completely filled with contrast. The subsequent images showed the blood in white color moving in over a background of black contrast. The arterial phase started when the blood began moving in and ended when the contrast disappeared from the distal arterial vasculature as the contrast was replaced by blood. The machine learning (ML) program had 2 models (built on Python). Model 1 was built based on U-net and Densenet-121 for vessel segmentation. Model 2 was used for classification of flow. The model 2 was trained based on the convolutional neural network. The data to be collected was the duration of the arterial phase and the recurrence of ACS within one year follow-upResults: 45 patients with ACS (elevated troponin level (50-100mg), reversible stress thallium), underwent coronary angiogram. The angiograms of 10 control patients showed a normal arterial phase (AP) of 1.56 sec. It was prolonged at 2.5sec in 45 patients with ACS (p<0.05). After 1 year follow-up, 35 patients had no further ACS if their LDL cholesterol was well controlled (<75mg%), blood pressure (BP<130mmHg) and the patients stopped smoking. In 10 patients who continued to have uncontrolled LDL, high BP and especially smoking, they developed ACS including death.Conclusions: In ACS patients, a prolonged arterial phase associated with reversible change in nuclear scan and normal coronary arteries identified the patients of high risk. Aggressive treatment of risk factors protected these patients of new ACS. Failure to control risk factors lead to repeat ACS. New trials are needed to confirm and guide new personalized medicine approach.