Acute ST-segment elevation myocardial infarction (STEMI) is the result of acute thrombus occlusion of the lumen due to coronary plaque rupture, and emergency direct percutaneous coronary intervention (PCI) is currently the main measure to open the infarct-related artery (IRA) in a timely and effective manner and to perform the most effective “reperfusion” treatment for STEMI. and the preferred treatment strategy. However, during the emergency PCI procedure, fresh thrombus or plaque is crushed and dislodged during conventional balloon dilation and stent placement (especially the molecular mediators and activated platelets within the plaque) often cause embolism in the distal part of the vessel to varying degrees, resulting in “slow flow” or “no-reflow” (no-reflow). reflow”. It also aggravates systemic stress due to the long duration of the procedure. These are important factors that lead to deterioration, hemodynamic instability, and increased mortality, and seriously affect the immediate outcome and long-term prognosis of STEMI patients. Conventional emergency PCI, which does not include thrombus aspiration, is only a routine balloon dilation and stent implantation procedure in STEMI patients immediately after coronary identification of the IRA with a guidewire through the occluded lesion to the distal end. In addition to PTCA and coronary stent implantation, PCI also includes techniques such as rotational grinding, directional spinotomy, aspiration and laser angioplasty that can relieve coronary stenosis; undoubtedly, with the application of aspiration catheters, it is expected that these thrombus, plaque and other tangible components and invisible components such as inflammatory factors and tissue factors will be extracted from the body in order to resolve or alleviate The subsequent complications associated with vascular blockage and secondary hypercoagulable and inflammatory reactions are expected to be resolved or alleviated. The First Affiliated Hospital of Henan College of Traditional Chinese Medicine, Department of Cardiology, Care Min I. Significance of thrombus aspiration: The coronary thrombus aspiration device is specifically designed for the aspiration of thrombus and plaque in coronary occlusion-associated vessels (IRAs), and has been widely used in emergency PCI at home and abroad in recent years to prevent coronary microembolism, improve coronary blood flow, reduce the incidence of no-reflow, and improve the prognosis of PCI in STEMI patients. . The Thrombus Aspiration Study (TAPAS) trial confirmed that the application of thrombus aspiration prior to emergency PCI balloon dilation or stent placement significantly improved myocardial reperfusion, reduced the incidence of no-reflow, and reduced mortality within 1 year. The heavier the thrombus load, the greater the benefit from thrombus aspiration management. The thrombus score is defined as follows: 0, no thrombus; 1, vague thrombus shadow; 2, definite thrombus image with a length of less than 1/2 the intravascular diameter; 3, definite thrombus with a length between 1/2 and 2 times the intravascular diameter; and 4, definite thrombus with a length greater than 2 times the intravascular diameter. A coronary angiogram showing one of the following features of the IRA is indicative of high thrombus load: ① a long strip of thrombus greater than three times the inner diameter of the reference vessel ② the presence of a floating thrombus proximal to the occlusion ③ a strip of thrombus >5 mm long proximal to the occlusion ④ a sudden flush occlusion without progressive thinning of the vessel proximal to the occlusion ⑤ a reference lumen inner diameter of the IRA >4.0 mm ⑥ contrast retention distal to the occlusion, etc. The TIMI grading of coronary blood flow and the grading of myocardial tissue perfusion color rendering (cardiac agent contrast staining density, MBG) are as follows: blood flow grading, TIMI: grade 0, no filling and emptying in the myocardium of the infarct-related area; grade 1, slow filling and no emptying in the myocardium of the infarct-related area, and the contrast agent is still retained when reconstructed after 30 seconds; grade 2, complete filling and emptying in the myocardium of the infarct-related area, but MBG grading: MBG grade 0, no myocardial imaging; MBG grade 1, only minimal myocardial imaging; MBG grade 2, moderate myocardial imaging, but significant ipsilateral or contralateral IRA-dominated areas; MBG grade 3, normal myocardial imaging, comparable to ipsilateral or contralateral non-IRA dominated areas for comparison; when there is persistent myocardial visualization, this phenomenon shows leakage of the contrast agent outside the vessel and is classified as grade 0. The MBG grade 0-2 is defined as poor myocardial perfusion imaging, and MBG grade 3 is defined as normal myocardial perfusion. It was found that even with direct PCI of the offender vessel to achieve TIMI grade 3 blood flow, approximately 30% of patients still had no myocardial tissue level perfusion and presented with persistent chest pain and ST-segment elevation on the ECG. Therefore, ST-segment regression rate (STR) is a sensitive index for evaluating myocardial reperfusion. And in AMI patients with good myocardial perfusion confirmed by myocardial sonography, their elevated ST segments rapidly decreased; whereas in patients with no myocardial reperfusion, their ST segments continued not to drop or even continued to elevate on the original basis, and the study showed that 50% of STRR indicated good myocardial perfusion. Even though coronary angiography in patients with successful thrombolysis confirmed a TIMI grade 3 coronary flow, a significant proportion still showed poor myocardial perfusion colorimetric imaging (BMG); BMG imaging is a more reflective indicator of myocardial injury and affects prognosis. Clinical studies have shown that in STEMI patients with high thrombus load in the IRA, the application of thrombus aspiration therapy in emergency direct PCI has proven to be effective and safe regardless of the recovery time from chest pain, cardiac enzyme levels, STR, coronary angiography TIMI grade and MBG grade, and Mace event evaluation. All patients were given a loading dose of aspirin 300 mg and clopidogrel 300-600 mg before emergency coronary angiography, standard heparin anticoagulation (100 U/kg) intraoperatively, and intravenous tirofiban 10 μg/kg before angiography, followed by 0.15 μg/kg/min intravenous micropump for 36 h. High thrombus load was detected on coronary angiography and then given In conventional PCI, a guiding catheter and a 0.014-inch coronary soft guidewire were fed through the arterial sheath into the distal end of the IRA, and a thrombus aspiration catheter was fed along the wire until approximately 2 cm before the thrombotic lesion, and a 50-ml manual negative pressure suction device was attached to the end and started aspiration under X-ray fluoroscopy; aspiration was performed as deeply as possible from the proximal to the distal end, and the same procedure was repeated at other angles. The same operation was repeated 2-3 times, 5-6 times if necessary, until the thrombus shadow disappeared or decreased and the antegrade blood flow improved, as determined by the contrast. The changes in IRA flow are then recorded in detail, and a stent of appropriate diameter is selected according to the characteristics of the lesion and stent implantation is performed, with a single expansion and release of the stent in place according to the prescribed standard release pressure as far as possible during the operation (avoid high pressure or multiple expansions as far as possible). The following points should be noted when using thrombus aspiration catheter for thrombus aspiration: ①, negative pressure aspiration should be started when the head end of the aspiration catheter is close to the occluded segment; ②, thrombus aspiration should be performed not only in the occluded segment, but also in the distal segment of the vessel; ③, thrombus aspiration should be patient enough, repeatedly and carefully aspirated, and the effect of thrombus aspiration in the “criminal vessel” can be checked by intermittent imaging ④, thrombus aspiration process, such as stopping the return of blood or slow return of blood, often indicates that there may be a large thrombus blocking the aspiration catheter, need to withdraw the catheter under negative pressure, flush with heparin saline and then thrombus aspiration; ⑤, back to withdraw the aspiration catheter to maintain negative pressure, to avoid the aspiration catheter thrombus off to the proximal end of the occluded vessel segment, or even cause other vascular embolism; ⑥, after withdrawing the aspiration catheter, to return to the guide catheter (6) After withdrawing the aspiration catheter, the blood inside the guide catheter should be sucked back (sometimes small bubbles or thrombus will be sucked back) to avoid possible gas or thromboembolism; (7) After thrombus aspiration, nitroglycerin should be injected into the coronary artery to release the vasospasm. A study found that in patients with emergency STEMI, after application of aspiration catheters to aspirate thrombus, the incidence of no recurrent flow and slow flow after stent placement was 0 (0/63), the incidence of balloon-free predilation was 26.9% (17/63), the incidence of postoperative heart failure was 0 (0/63), the incidence of no recurrent flow and slow flow after stenting was 8% (7/85) in the non-aspirated group, the incidence of balloon-free predilation was 8% (7/85), and the incidence of postoperative heart failure was 8% (7/85). (7/85), and 4.7% (4/85) incidence of postoperative heart failure. There was no significant difference in the incidence of major cardiovascular events during hospitalization between the two groups. The time from guidewire passage to stent implantation, from guidewire passage to TIMI class 3 flow, and from pre-dilation/stent implantation to TIMI class 3 flow were significantly lower. 26.9% (17/63) of patients with AMI underwent direct stenting during PCI in the aspirated group, most of the non-aspirated group required balloon pre-dilation followed by stenting, whereas only 8% (7/85) underwent direct stenting. Only 8% (7/85) were stented directly. The use of aspiration catheters improves the chances of direct stenting in AMI patients, shortens the time to revascularization, reduces the damage to the endothelium from balloon predilation, and minimizes the extent of myocardial infarction. Thrombus aspiration is effective in the vast majority of cases, and TIMI grade 2-3 flow can be achieved after aspiration. Therefore, thrombus aspiration does not prolong the time to vessel opening compared to predilation. As the thrombus is removed from the lesion, the morphology of the lesion is revealed and the perfusion at the end of the lesion is obtained, and the thrombus load is rapidly reduced in the early stages, resulting in better coronary flow. In some patients, adequate blood flow can be obtained safely and effectively without pre-dilation of the balloon, reducing the possible vascular injury and plaque dislodgement caused by repeated balloon dilatation, thus reducing the occurrence of no or slow recurrent flow after PCI and making subsequent stenting relatively simple and safe. The visible aspirates from STEMI patients undergoing emergency PCI were collected and classified according to the pathology seen on light microscopy as erythrocyte-dominant thrombus (red thrombus), platelet/fibrin-dominant thrombus (white thrombus), mixed thrombus (erythrocyte and platelet/fibrin content approximation), plaque, and plasma precipitate components. The thrombi were classified according to their chronological phase into fresh thrombus (<1 d), lysed thrombus (1-5 d), fresh + lysed thrombus, and mechanized thrombus (>5 d). The group was divided into plaque-free and plaque groups according to the presence or absence of plaque material on light microscopy; the study reported partial thrombosis of STEMI within 6 hours of onset for at least >1 day. Fresh thrombi (<1 day) accounted for 49% of the thrombi aspirated from the coronary arteries of 211 STEMI patients, and old (with autolysis and estimated time to formation of 1-5 days) and mechanized thrombi (>5 days) accounted for 51%. Their findings suggest that atheromatous plaque rupture and thrombosis may occur days before complete coronary lumen occlusion. Therefore, thrombolysis alone is effective only for fresh thrombi and less effective for older or mechanized thrombi, whereas aggressive aspiration is still effective even for thrombi half a month after STEMI. IV Prospects for clinical application of thrombus aspiration Routine thrombus aspiration should also be performed in primary (distal) or collateral vessels (e.g., obtuse marginal, diagonal, posterior left ventricular, or posterior descending branches) with a small estimated infarct size, such as an offender vessel diameter of less than 2.25 mm, and significant thrombotic signs and clinical symptoms, if the decision to intervene is made. This is because, in the absence of stent placement, thrombus aspiration alone can remove the thrombus and terminate the procedure by achieving TIMI grade 2-3 flow, whereas balloon dilation alone is prone to distal embolization or entrapment. In the vast majority of cases, a normal aspiration catheter can be passed through the collateral vessels and aspirated successfully. Our study found that the procedure can be terminated in patients whose IRA flow has reached TIMI grade 3 simply by repeated aspiration of the thrombus, but also because of complex lesions, or because of residual stenosis of critical or subcritical degree, or hemodynamic instability, and when re-imaging at 10-14 days revealed a significant reduction in coronary stenosis without further stenting in 4/18 cases. In actual clinical practice, emergency STEMI patients require two procedures to complete, except for single-branch lesions. The principle is that only IRAs are treated during emergency PCI, and the rest of the offender-related lesions (CRL) lesions are completed during the second procedure. Our study is a staged approach to catheter thrombus aspiration and stent implantation from the clinical reality, based on the theory that the same two procedures, the use of thrombus aspiration catheter to discharge the high load of thrombus through repeated aspiration in the appropriate patient emergency, if the coronary flow TIMI classification up to grade 3 or at least grade 2, the procedure can be ended immediately; has been effectively achieved in a relatively short period of time acute STEMI to achieve the goal of “reperfusion”, is also the best embodiment of “time is the myocardium, time is life”; then in the effective anticoagulation and antiplatelet and anti-inflammatory drugs to protect the body to recover to the appropriate time, together with the treatment of CRL lesions The IRA residual lesions are treated at the same time. This undoubtedly evolves an emergency procedure into an elective general surgery with the same goals, with obvious advantages. The results showed that stenting (number, diameter, length, and dilation pressure) and intraoperative complication rates were significantly better in the second-stage procedure than in the control group with PCI done in a single routine procedure. For those who were aspirated via aspiration catheter after thrombolytic recanalization, their MBG imaging grade was significantly improved; for patients with relatively long infarct duration but with indications for PCI, if diagnostic imaging reveals TIMI grade 0-1 or TIMI grade 2-3 combined with severe stenosis, thrombus aspiration should also be actively performed from the perspective of removing thrombus or plaque material (especially intraplaque molecular media) to prevent distal embolization and no recurrent flow. In addition, common aspiration catheters provide a route for superselective infusion of drugs, among others. Compared to intravenous route drug administration, intracoronary infusion of glycoprotein IIb/IIIa receptor inhibitors via guiding catheters increases intracoronary drug concentrations and reduces systemic bleeding side effects, meeting the need for intensive anticoagulation after aspiration alone. Therefore, catheter thrombus aspiration is likely to become a mandatory technique for emergency PCI procedures. References: omitted