A risk stratification scheme for selection of a glycoprotein IIb/IIIa inhibitor during percutaneous coronary intervention based on clinical and angiographic criteria.

I randomized trials of glycoprotein (GP) IIb/IIIa inhibitors during percutaneous coronary intervention (PCI), it appears that the trials involving abciximab have the greatest benefit, followed by trials with small molecules. Despite a wide variety of clinical and angiographic settings in which all GP IIb/IIIa inhibitors have been studied, in some subgroups, such as small vessels, restenotic vessels, and vein graft lesions, no clear-cut benefit has been shown. To date, there is only 1 randomized trial comparing abciximab with tirofiban during PCI (do Tirofiban And ReoPro Give similar Efficacy Trial [TARGET]) and no headto-head randomized trial comparing the 3 available GP IIb/IIIa inhibitors. Therefore, the decision to use 1 agent over another is based on a case-by-case analysis of risk/benefit versus cost. Considering an average incidence of periprocedural creatine kinase (CK)-MB elevation of 15%, a total of 1,500 patients (500 in each group) will have 80% power to show a 15% relative (3% absolute) difference among the various groups. Based on our earlier observation and prior published reports of periprocedural CK-MB elevation and ischemic procedural events, we formulated a risk stratification scheme for use of a particular GP IIb/IIIa inhibitor during PCI: abciximab for the high-risk group, small molecules for the intermediate-risk group, and no GP IIb/IIIa inhibitor in low-risk group, with the provision of abciximab use as bailout for procedural complications in intermediate and low-risk groups. In the present study, this risk stratification scheme for selecting a particular GP IIb/IIIa inhibitor during PCI was prospectively evaluated to assess the incidence of periprocedural CK-MB elevation, bailout use of abciximab, and 30-day major adverse cardiac events. All patients (n 1,875) undergoing PCI at our institution from January to December 1999 were analyzed based on the risk stratification protocol for use of GP IIb/IIIa inhibitors. Patients with acute myocardial infarction (MI) ( 24 hours), elevated baseline CK-MB values, preprocedure GP IIb/IIIa inhibitor use, serum creatinine 2.5 mg/dl, platelet count 150 10/L, and contraindication to GP IIb/IIIa inhibitor use were excluded. A risk stratification protocol was developed based on the clinical and angiographic criteria (Table 1). Abciximab was recommended for high-risk subsets, small molecules for intermediaterisk subjects, and no GP IIb/IIIa inhibitors for the low-risk group. The choice of small molecules in the intermediate-risk group was left to the interventionalist. The study population consisted of 1,655 consecutive patients undergoing PCI. GP IIb/IIIa inhibitors were used in 75.1% of patients, abciximab in 48.2% (n 798), tirofiban in 13.3% (n 220), eptifibatide in 13.6% (n 225), and no GP IIb/IIIa inhibitors in 24.9% (n 412). An independent investigator verified the protocol compliance from the case report forms. The compliance for the use of an individual agent as per protocol guideline was 98% in each risk group. Baseline cardiac enzymes, complete blood count with platelets, and chemistry were measured in all patients and repeated at 4 to 8 hours and 16 to 24 hours after the procedure, and thereafter if these measurements remained abnormal. All patients received aspirin 325 mg orally, clopidogrel 300 mg orally, and a 50 to 70 U/kg intravenous bolus of heparin. Subsequently, periodic intravenous heparin boluses were given to maintain the activated clotting time between 225 and 300 seconds, with a trend toward lower values in the abciximab group. The GP IIb/IIIa inhibitors were administered in the following doses: abciximab (Evaluation of IIb/IIIa Platelet Inhibitor for STENTing [EPISTENT] trial dose), 0.25 mg/kg bolus with infusion of 0.125 g/ kg/min (maximum 10 g/min) for 12 hours; tirofiban (Randomized Efficacy Study of Tirofiban for Outcomes and REstenosis [RESTORE] trial dose), 10 g/kg bolus with infusion of 0.15 g/kg/min for 16 to 24 hours; eptifibatide (Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin Therapy [PURSUIT] trial dose), 180 g/kg bolus with infusion of 2.0 g/kg/min for 16 to 24 hours. All interventions were performed using conventional techniques, and the choice of the interventional device was left to the operator (stents were used in 88.6% of cases). Complete angiographic vessel and lesion characteristics and procedural results were recorded after each coronary intervention. Angiographic success: residual stenosis 30% From the Cardiac Catheterization Laboratory, Cardiovascular Institute, Mount Sinai Hospital, New York, New York. Dr. Sharma’s address is: Mount Sinai Hospital, Cardiac Catheterization Laboratory, Cardiovascular Institute, Cardiology-Box 1030, One Gustave Levy Place, New York, New York 10029-6574. E-mail: samin.sharma@mssm.edu. Manuscript received June 13, 2001; revised manuscript received and accepted July 24, 2001.