The First Affiliated Hospital of Henan College of Traditional Chinese Medicine Author: Care Min Xie Jinhong A. Chest discomfort, coronary critical lesions, timely identification of “criminal lesions” and identification of vulnerable plaques The First Affiliated Hospital of Henan College of Traditional Chinese Medicine, Department of Cardiology Care Min Coronary heart disease is a common disease, multi-morbidity, seriously affects people’s physical and mental health, and become a threat to the lives of people It is the number one killer. Although our understanding of coronary heart disease has been more in-depth, and we have also strengthened the corresponding preventive measures, in a sense, we have achieved certain results, but it is still far from enough. The incidence of serious adverse events in coronary heart disease, especially acute coronary syndrome (ACS), is still not effectively controlled. The focus of our treatment has also been on the presenting patient. It has been established that recent coronary angiographic data in patients with acute myocardial infarction confirm that approximately 68% of pre-MI coronary stenoses are less than 50%, 18% of pre-MI stenoses are approximately 50-70%, and only 14% of pre-MI stenoses are approximately greater than 70%. Therefore, it would be very meaningful to detect or screen those patients with acute myocardial infarction before the onset of the disease; however, the current examination method still uses coronary angiography as the “gold standard”, and as mentioned above, only a few can be detected, and in fact, the coronary arteries themselves are often abnormal. Saka, et al. performed OCT of offender lesions before PCI in 128 patients with ACS and found that thin fibrous caps and lipid-rich plaques as vulnerable plaques were common to these lesions, especially when combined with multiple plaque ruptures. Therefore, it is proposed that multiple lesions are closely associated with the occurrence of re-MACE and that detailed risk assessment and intensive management of non-target disease should also be performed after PCI for offender lesions. the Prospect study also found that the chance of major adverse cardiac events (MACE) in ACS patients 3 years after PCI was not significantly different between those due to offender and non-offender lesions; suggesting that ACS patients do have “vulnerable plaque, vulnerable vessel, vulnerable blood, and vulnerable organism”. It is currently believed that intervention is advocated if patients with adventitial lesions have typical clinical evidence of angina pectoris and myocardial ischemia. If there is no objective evidence of myocardial ischemia, or insufficient evidence, or if multiple adventitial lesions exist in the same vessel, further ancillary diagnostic methods are required at this time to assist in guiding the decision on therapeutic measures. Vulnerable plaques are the main pathological mechanism leading to clinical ACS events and are characterized by large “lipid nuclei” rich in extracellular lipid cores and cellular debris with a thin external fibrous cap (usually less than 65 μm), especially at the junction between the lesion and the adjacent normal endothelium, with a large number of There is a large infiltration of inflammatory cells such as macrophages and T cells. Identification of vulnerable plaques is important to prevent adverse cardiac events. Ruptured thin fibrous cap lesions (TCFA) are mostly criminal lesions, whereas TCFA are lesions that are highly susceptible to rupture or are about to rupture; these lesions are clearly present in patients with ACS, but they are indeed rarely detected by coronary angiography, in other words a significant proportion of patients with ACS do not have significant stenosis on coronary angiography. However, intracoronary OCT technology can provide the above-mentioned high-resolution cross-sectional images of the lumen, which can identify “criminal lesions” and detect vulnerable lesions. Thrombosis caused by rupture of vulnerable plaque is now recognized as one of the most important mechanisms in the development of acute coronary syndromes. Although the unstable plaque is characterized by a thin fibrous cap and a thick lipid pool, in practice it is more difficult to detect a thrombus in a <65% fragile plaque. OCT is currently an advanced optical imaging technique with a high resolution of up to 10 μm, and its greatest advantage is its high resolution, which is by far the highest resolution intravascular imaging technique with a resolution of 5-10 μm, 10 times higher than that of intravascular ultrasound. It is also called "optical biopsy" because it is the highest resolution intravascular imaging technique with a resolution of 5-10 μm, which is 10 times higher than the resolution of intravascular ultrasound imaging, and the identification of vulnerable plaques is close to the level of the observed tissue. In the treatment of critical lesions, the advantage of OCT is the accurate identification of vulnerable plaques, micro lesions, and thrombi. Many critical lesions with moderate stenosis on coronary angiography are found to have vulnerable lesions after OCT, and these critical lesions are precisely the "criminal" lesions that cause ACS, especially those lipid-rich vulnerable plaques, which are prone to rupture on the basis of spasm, leading to local obstruction by thrombus and sudden death, acute myocardial infarction, and other serious diseases. This can lead to sudden death, acute myocardial infarction, and other serious cardiac events. OCT can not only help the operator to accurately identify the real "criminal" lesions and guide the interventional treatment, but also provide early warning for some vulnerable plaques. In addition, if a vulnerable plaque has ruptured, a significant number of patients have actually experienced a clinical event, which could have been prevented if it had been predicted before the vulnerable lesion ruptured. Local thrombosis was seen in 49% of patients with plaque rupture, with the thrombus site mostly located at the site of significant primary stenosis, and there was no relationship between thrombosis at the rupture site and the presence or absence of cholesterol crystals. Therefore, it is proposed that the presence of cholesterol crystals within the plaque is the main risk factor to predict plaque rupture. If TCFA is found to be about to rupture, that would predict a clinical event. Whereas it is still difficult to screen for this with current technology, OCT is the only one that can both detect TCFA lesions and identify cholesterol crystals in necrotic plaques. Therefore, it is said that OCT is a very promising technique for determining the imminent rupture of TCFA. Therefore, it is said that further IVUS, OCT or FFR should be performed in patients with angina symptoms and clinical evidence of objective myocardial ischemia. The coronary arteriography technique, which is the "gold standard" for the evaluation of coronary lesions at the anatomical level, still has many limitations in determining the degree of stenosis and identifying vulnerable plaques in complex lesions. Epidemiological data show that in 60%-70% of patients with acute coronary syndromes, the degree of stenosis of the underlying lesion is 30%-70%. Therefore, treatment strategies for adventitial lesions are receiving increasing attention from interventionalists. Cardiovascular physicians should make a comprehensive evaluation of objective evidence of myocardial ischemia, imaging and coronary physiological function, and strictly control the indications for intervention. Current evidence supports the administration of drug-eluting stent (DES) interventions in patients with lesions that are vulnerable plaques on imaging, or those with rupture changes in the plaque, or those with abnormal coronary physiologic function on FFR. In the CLI-OPCI study, coronary angiography alone and coronary angiography plus OCT were used to guide the PCI process in 670 cases of coronary PCI, as OCT can reveal information that is difficult to detect on coronary angiography, such as tears at both ends of the stent, poor stent apposition, poor stent expansion, and thrombosis. As a result, 37.4% of patients required intraoperative re-stenting or post-expansion with a high-pressure balloon; if coronary angiography plus OCT was used to guide the PCI process, 12-month cardiac mortality and nonfatal infarction were significantly better than in the coronary angiography alone group, and no significant side effects were found during the OCT examination. One study found that in STEMI patients, only 50% of patients had complete stent coverage of thin fibrous cap plaque (TCFA) during PCI, while 35% of patients had no proximal stent coverage of TCFA and 15% had no proximal or distal coverage of TCFA. these findings were significantly associated with poor prognosis both proximally and distally after PCI. shino et al. evaluated OCT parameters in 34 patients correlation with FFR. All patients underwent quantitative coronary angiography (QCA), OCT and FFR, and OCT determined the minimum lumen diameter (MLD), MLA and lumen area stenosis rate. The results showed that FFR values were significantly correlated with MLD (P<0.001), MLA (P<0.001) and lumen area stenosis (P=0.006). The cut-off values for predicting functionally significant stenosis (FFR<0.75) by OCT were MLD<1.35 mm, MLA<1.91 mm2 and lumen area stenosis<75.6%, with sensitivities of 85 The sensitivity was 85%, 85% and 60%, the specificity was 69%, 69% and 81.2%, the positive predictive values were 80%, 77.3% and 73.9%, and the negative predictive values were 61.9%, 78.6% and 76.9%, respectively. The study concluded that OCT anatomical parameters were significantly correlated with FFR values and that MLD, MLA and lumen area stenosis measured by OCT were significant predictors of functionally significant coronary stenosis. In addition to its morphological diagnostic function, OCT was also found to be of moderate value in the functional diagnosis of coronary lesions: 82% sensitivity and 63% specificity. The introduction of drug-eluting stents (DES) has significantly reduced the rate of in-stent restenosis and target revascularization. However, DES, while effectively inhibiting smooth muscle cell hyperproliferation and migration, inhibits endothelial repair and delays the endothelialization process of the stent, resulting in incomplete coverage of the stent support rod with new endothelium after DES implantation, thereby increasing the risk of in-stent thrombosis (IST). Therefore, accurate identification of de novo endothelial coverage on the stent surface is essential to evaluate the effectiveness and safety of DES. Although the incidence of IST is low (0.5% to 0.6%), it can have fatal consequences for patients (sudden death and myocardial infarction), and therefore the issue of late thrombosis is now doubly controversial. the formation of IST may be associated with several factors: premature discontinuation of antiplatelet agents, delayed stent endothelialization, local inflammatory reactions and allergic reactions in the vessel due to stent polymers. poor stent apposition, stent support rod piercing into the lipid core of the plaque, and lesion characteristics (e.g., open lesions, curved lesions). Of particular interest is the issue of stent endothelial coverage. Recent studies have confirmed that late in-stent thrombosis is closely associated with incomplete DES endothelialization, and Aloke V. Finn et al. demonstrated that de novo endothelial coverage of stents is the best morphological predictor of IST. Although some stents are covered with neoplastic endothelium, the question of whether they are composed of normal endothelial cells and whether they have normal endothelial functions (e.g., antithrombotic) remains to be confirmed by further studies. A clinical study with 9-month OCT follow-up after stent implantation in 68 patients showed that OCT can clearly compare poor apposition, endothelial coverage on the surface of stent trabeculae, and neoplastic endothelial proliferation after implantation of different drug-eluting stents. The results of a recent clinical study enrolling 36 patients with sirolimus drug-eluting stent (SES) implantation at 6 and 12 months OCT evaluation of reendothelialization and de novo endothelial coverage suggest that at 6 and 12 months, most of the stent support rods were covered with de novo endothelium, but only a small percentage of the rods were completely covered, therefore, by applying OCT to evaluate the uncovered stent support rods The condition of the uncovered stent support rods was evaluated by applying OCT to decide whether to take longer antiplatelet therapy. The causes of in-stent restenosis have also become clearer due to the application of OCT: various types of in-stent thrombosis, both due to poor endothelial crawling and due to rupture of neoplastic plaques, especially those with very advanced in-stent thrombosis; stenosis due to in-stent collagen and smooth muscle hyperplasia, which are relatively stable stenotic lesions that develop slowly. Of course, for the analysis of the causes of in-stent thrombosis, OCT examination has the unique advantage; different causes determine different treatment plans: poor endothelial healing due to poor stent apposition, application of high-pressure balloon post-dilatation to make it fully apposed; in case of unexplained poor endothelial cell proliferation, prolonged application of anti-platelet drugs and pro-endothelial cell proliferation measures should be taken; in case of in-stent de novo TCFA formation, the If it is the formation of new TCFA in the stent, it should be reinserted with DES and enhanced lipid-lowering and anti-inflammatory treatment. IV. Exploration of ineffective OMT treatment and differences in the efficacy of different stents Our Professor Zhao Level reported that in patients with acute coronary syndrome (ACS) receiving optimal coronary therapy (OMT), statin dose doubling failed to produce a significant clinical benefit, although it resulted in a further 5.4% reduction in low-density lipoprotein cholesterol (LDL-C) based on the application of conventional dose of statin. In this study, a multicenter, randomized, open, different-dose comparative study design protocol was used to enroll 1355 patients with ACS from 20 clinical collaborative medical centers in 8 provinces and autonomous regions in China from November 2007 to November 2010. With a mean follow-up of 2 years, the clinical efficacy of lipid regulation in the intensive statin group (atorvastatin 20 mg/d or other equal-dose statin, n=680) was compared with that in the conventional statin group (atorvastatin 10 mg/d or other equal-dose statin, n=675). The primary endpoints observed included cardiac death, nonfatal myocardial infarction, revascularization, ischemic stroke, unstable angina requiring hospitalization, and severe heart failure requiring hospitalization. The mean LDL-C level was only 2.65 mmol/L. After 3 months of treatment, LDL-C was reduced by 24.1% and 18.7% in the intensive lipid regulating group and the conventional lipid regulating group, respectively, and the difference between the two groups was statistically significant (P < 0.001). At a mean follow-up of 2 years, only 48 cases had clinical primary endpoint events (28 cases in the intensive lipid modulation group and 20 cases in the conventional lipid modulation group), and the difference between the two groups was not statistically significant. There were no statistically significant differences between the groups in terms of clinical adverse effects and abnormal laboratory parameters. This study suggests that statin therapy can solve the major problems of most patients, but not all of them. The specific reasons need to be further explored. Especially with the help of next-generation OCT technology, frequency domain OCT (OFDI) is the new second-generation OCT system. It has a faster imaging speed compared with the first generation of time-domain OCT, eliminating the need to block the coronary blood flow with a balloon, and can be imaged in 3 seconds; conventional OCT can image only one point on the surface, while using MGH-Wellman's new laser technology, OFDI can image 1000 such points simultaneously. In the fiber optic catheter probe, there is a rotating laser head that constantly changes wavelength. By measuring the reflection of light at each wavelength, the data needed for imaging can be obtained. It is expected that this will lead to the morphological effects of different statin doses on vulnerable plaques in ACS patients. OCT found that in-stent atherosclerotic lesion development was significantly faster within 2 years after drug-coated stent (DES) implantation than with bare stents. Hou used OCT to examine 39 patients who had 60 bare stents implanted 6.5±1.3 years ago and found lipid-rich plaques in 33% of patients and TAFC in 41% of patients at follow-up. Kohei ishibashi et al. found that hypointense areas around stent filaments occurred more commonly after paclitaxel drug-eluting stent (PES) stenting. Peripheral hypoechoic areas were more pronounced after drug-coated stent implantation than bare stents, and the cause of generation may be related to local stimulation of the stent. It is also suggested that the healing response of the vessel wall to stent injury after PES may be different from that of other stents. In conclusion, OCT technique has become the main method for in vivo study of the pathogenesis of coronary heart disease and the prognosis of interventional treatment.