Effects of Intravenous Administration of Tissue Plasminogen Activator Before Thrombectomy in Patients With Acute Myocardial Infarction

Abstract

ercutaneous coronary intervention (PCI) for patients with acute myocardial infarction (AMI) carries a risk of distal embolization of atheromatous and thrombic debris. These adverse effects of PCI potentially result in so-called 'no-reflow phenomenon', which is characterized by impaired myocardial perfusion, despite reopening of the epicardial coronary arteries. 1,2 Embolization of plaque and thrombic debris induced by PCI can lead to the obstruction of distal coronary arteries, limiting the efficacy, and the extent of myocardial reperfusion. 3 The impaired coronary microcirculation after PCI causes persistent abnormality in myocardial metabolism and increased cardiomyocyte death, which might limit myocardial salvage gained by PCI. [3][4][5] A number of techniques to protect against distal embolization during PCI have developed in recent years. Of these, several studies have emphasized the efficacy of thrombectomy before PCI in reducing distal embolization and improving coronary microvascular perfusion. 6,7 However, the efficacy of thrombectomy is limited by the fact that complete aspiration of thrombus before PIC is not possible and residual thrombus are liberated during PCI. 8 Therefore, we designed a prospective and randomized trial to test the hypothesis whether thrombolysis by intra- Circulation Journal Vol.70, March 2006venous administration with mutant tissue plasminogen activator (Mt-PA) improves the outcome of thrombectomy and PCI in patents with AMI. The rationale for using Mt-PA before thrombectomy and PCI in patients with AMI is 2-fold. First, this facilitated PCI technique might enhance the efficacy of PIC by earlier reopening of infarction-related artery (IRA). Second, thrombolysis by Mt-PA before thrombectomy might allow more complete aspiration of thrombic debris by thrombectomy devices, thereby improving the efficacy of thrombectomy to protect coronary microcirculation. The results of our trial suggest that although the use of Mt-PA before thrombectomy improves coronary microcirculation immediately after PCI, it is not superior in improving left ventricular (LV) function over thrombectomy alone. Methods SubjectsConsecutive 44 patients who were admitted in our coronary care unit for the first onset of ST-segment elevation AMI without contraindication for Mt-PA were enrolled in the study. These patients received the initial therapy by oral administration with 100 mg of aspirin and 100 mg of ticlopidine and intravenous administration with 60 units/kg of haparin and, when necessary, they received intravenous isosorbide dinitrite and/or propranolol. They were, then, randomly assigned to either thrombectomy with Mt-PA pretreatment (group T; n=23) or thrombectomy alone (group N; n=21) using an envelope method. Group T patients received a bolus half-dose of monteplase (13,750 IU/kg) intravenously. The protocol of the study was approved by Background Myocardial salvage after acute myocardial infarction (AMI) largely depends on the removal of infarct-related thrombus. Although both thrombolysis and thrombe...

Elevated Plasma Plasminogen Activator Inhibitor Type-1 is an Independent Predictor of Coronary Microvascular Dysfunction in Hypertension

“…Mutant t-PA administration before thrombectomy improves Thrombolysis in Myocardial Infarction myocardial perfusion grade in acute myocardial infarction. 35 Because PAI-1 inhibits t-PA-mediated vasoactivity, 36 reduced coronary vasoreactivity mediated by hypofibrinolysis may be an additional mechanism by which PAI-1 contributes to vasculopathy. 37 The association of PAI-1 with vessel wall damage and clinical cardiac events 11,38,39 may be at least partly caused by reduced vascular tone by PAI-1.…”