Published online Aug 6, 2019. doi: 10.12998/wjcc.v7.i15.2013
Peer-review started: March 28, 2019
First decision: May 31, 2019
Revised: June 18, 2019
Accepted: July 3, 2019
Article in press: July 3, 2019
Published online: August 6, 2019
Acute myocardial infarction (AMI) is a leading cause of mortality. Early reperfusion to restore blood flow is crucial to successful treatment. An increasing number of patients have benefited from direct percutaneous coronary intervention (PCI). However, coronary artery no-reflow or slow blood flow after stent implantation and coronary revascularization occurred in direct PCI in some cases. The exact mechanism of no reflow or slow blood flow remains unclear
Although in the current reperfusion regimen, an increasing number of patients have benefited from direct PCI, there have been some cases of coronary artery no-reflow or slow blood flow after stent implantation in direct PCI as well as coronary revascularization. The exact mechanism of no reflow or slow blood flow is still unclear. In order to understand whether there is a correlation between the components of coronary thrombosis and the absence of reflow or slow blood flow after coronary stent implantation in direct PCI, we collected data on direct PCI cases in our hospital between January 2016 and November 2018.
This study aims to investigate the correlation between intracoronary thrombus components and coronary blood flow after stent implantation in direct PCI in AMI.
A total of 154 patients with direct PCI who underwent thrombus catheter aspiration within < 3, 3–6 or 6–12 h of onset of AMI between January 2016 and November 2018 were included. The thrombus was removed for pathological examination. The patients of three groups according to the onset time of AMI were further divided into those with a white or red thrombus. The thrombolysis in myocardial infarction (TIMI) blood flow after stent implantation was recorded based on digital subtraction angiography during PCI. The number of patients with no-reflow and slow blood flow in each group was counted. Statistical analysis was performed on the onset time, thrombus component, and TIMI blood flow.
There were significant differences in thrombus components between the patients with acute ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction (P < 0.01). In the group with PCI < 3 h after onset of AMI, there was no significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups. In the groups with PCI 3–6 and 6–12 h after onset of AMI, there was a significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups (P < 0.01). There was a significant correlation between the onset time of AMI and the occurrence of no-reflow and slow blood flow during PCI (P < 0.01).
There was a significant correlation between the onset time of AMI and no reflow and slow blood flow during surgery. There was a significant difference in the thrombus components between acute ST-segment elevation myocardial infarction (STEMI) and acute non-ST-segment elevation myocardial infarction (NSTEMI). Patients with acute STEMI had mainly red thrombus, while those with acute NSTEMI had mainly white thrombus, which was closely related to the mechanism of different types of AMI. In patients with PCI at > 3 h after onset of AMI, those with white thrombus were more likely to have no reflow and slower blood flow after stent implantation than patients with red thrombosis. This can predict whether there is no reflow or slow blood flow after stent implantation. In patients with hyperthrombotic lesions that achieve complete recanalization of infarcted coronary arteries, pre-coronary administration of drugs, such as glycoprotein IIb/IIIa receptor antagonists or sodium nitroprusside, should be fully evaluated based on the nature of the thrombus extracted from the coronary arteries. Calcium antagonists can help reduce the occurrence of slow blood flow or no reflow.
In direct PCI, the onset time of AMI and color of coronary thrombus are often used to predict whether there will be no reflow or slow blood flow after stent implantation. However, the exact mechanism of no reflow or slow blood flow is not fully understood. Multiple pathophysiological mechanisms might be involved, including myocardial ischemia, myocardial reperfusion injury, distal coronary artery embolization and microcirculatory injury. More prospective studies are needed to be carried out in the future in AMI patients with direct PCI after stent implantation.