Prospective Randomized Controlled Clinical Study to Compare Tirofiban Intracoronary Bolus-Only vs Intravenous Bolus Plus Infusion in Patients With ST Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Primary percutaneous coronary intervention (PCI) is currently the treatment of choice for patients with acute ST elevation myocardial infarction (STEMI). Nevertheless, despite restoration of normal epicardial flow, myocardial perfusion remains impaired in approximately half of patients and is associated with a poor prognosis. A variety of invasive and non-invasive techniques have been proposed to evaluate microvascular perfusion and several invasive hemodynamic measures have been closely associated with microvascular damage.In order to improve microvascular perfusion after primary PCI, a variety of treatment strategies have been developed, such as adjunctive administration of glycoprotein IIb/IIIa inhibitors (GPIs). Although current ACC/AHA guidelines recommend that small molecule GPIs should be administered as a bolus followed by 18 hours of continuous infusion, changes in clinical practice may obviate the need for a maintenance infusion in current practice.

We hypothesized that when tirofiban is administered via intracoronary route, a bolus-only strategy may even be superior to intravenous bolus plus infusion strategy in maintaining myocardial perfusion. In order to evaluate microvascular function, we used a guidewire tipped with pressure and temperature sensors and measured the coronary hemodynamic parameters, as the index of microvascular resistance and coronary flow reserve, measures which have been closely associated with microvascular damage. In order to increase the predictive value of these indices, we performed these measurements four to five days after MI, because it has been shown that the extent of microvascular dysfunction changes, particularly within first 48 hours after reperfusion and stabilizes between 2 days and 1 week after perfusion