Phase I results show that the modified Thrombelastograph(R) Coagulation Analyzer (TEG(R)) assay to monitor platelet glycoprotein Ilb/IIIa (GPIIb/IIla) receptor blockade in patients being treated with c7E3 Fab provides an equivalent or better assessment of platelet GPIIb/IIla receptor blockade than the "gold standard" turbidimetric platelet aggregation test. Furthermore, in Phase I an individualized dosing algorithm with the use of the TEG(R) assay was developed. Using this algorithm, Phase II patients undergoing PTCA treated with c7E3 Fab can be individually dosed to achieve 80% reduction in Gp due to platelet inhibition. Further, Phase II will validate and expand the new test by: *Increasing the sample size to 400 to enhance the validity of the study, and increasing the participating hospitals to two, using institutions with a more diverse patient population. * Extending the Phase I study to encompass an additional GPIIb/IlIa inhibitor, eptibatide (Integrilin(TM)), to generalize the TEG(R) assessment of platelet GPIIb/IIla blockade. * Evaluating and refining the Phase I individualized dosing and comparing its clinical utility with the standard protocol of a weight-adjusted treatment of platelet blocker drugs to demonstrate reduced bleeding complications and decreased ischemic events and death. PROPOSED COMMERCIAL APPLICATIONS: The TEG(R) assay will be commercialized and used as a dedicated kit to monitor, assess and individualize dosing of GPIIb/IIia blockade in individuals being treated with c7E3 Fab, Integrilin or other new platelet inhibitor drugs.