cute myocardial infarction (AMI) is commonly related with thrombotic occlusion following a plaque rupture. Accordingly, early relief of the occluded coronary artery and restoration of the coronary flow to the jeopardized myocardium have been demonstrated to decrease mortality and adverse outcomes. 1,2 Primary percutaneous coronary intervention (PCI), with stent deployment in AMI, has been reported as more effective than balloon angioplasty, from the viewpoint of decreasing the rate of target vessel revascularization and restenosis. [3][4][5] However, as distal embolization of ruptured atherosclerotic plaque debris or thrombus is common during primary PCI with catheter-based interventions, stent deployment may also endow a greater chance of distal embolization than balloon angioplasty. 5 Evidence has accumulated that an obstruction of the distal microvasculature in the downstream bed of the infarct-related artery (IRA) is caused by distal embolization of thrombotic materials and platelets during intervention. [6][7][8] These are critical pathophysiologic events of myocardial infarction (MI), which is subsequently related to the slowflow or no-reflow phenomenon and associated with additional injury to the microvasculature of the myocardium and poor clinical outcomes. 9-13 Therefore, restoration of the epicardial coronary artery will not always guarantee reperfusion of the microvasculature of the myocardium and reperfusion at the myocardial tissue level by preserving the microvasculature is crucial, as is opening of the epicardial coronary artery during primary PCI. It has been suggested that a distal embolization protection device may be a safe and effective tool in preserving the microvasculature of the myocardium during primary PCI in AMI. [14][15][16][17][18] The coronary angiographic Thrombolysis In Myocardial Infarction (TIMI) myocardial perfusion grade (TMP) 19,20 and phasic coronary flow velocity patterns, as assessed by an intracoronary Doppler wire after primary PCI, both of which represent the myocardial reperfusion status and microvascular integrity of the IRA, are related to functional improvement of the left ventricle and prognosis of the patient. 21,22 Thus, the aim of the present study was to determine the effectiveness of the PercuSurge GuardWire ® system in preserving the microvascular integrity of the myocardium during primary PCI in AMI patients, using the intracoronary Doppler wire to measure coronary flow velocities and phasic coronary flow velocity patterns of the IRA following primary PCI.
Methods
Patient PopulationA total of 58 consecutive patients (mean age: 54±15 years; 46 males, 12 females) with first episode of ST-segment-elevated AMI, who had undergone primary PCI and a coronary Doppler flow study within 24 h of symptom onset, were enrolled. The diagnosis of AMI was based on characteristic chest pain persisting for more than 30 min, significant ST segment elevation (>1 mm in limb lead and >2 mm in precordial lead) in ≥2 contiguous ECG leads, and an