The benefits of anti-platelet therapy in the treatment of acute coronary syndrome (ACS) as an adjunct to percu-

The benefits of anti-platelet therapy in the treatment of acute coronary syndrome (ACS) as an adjunct to percutaneous coronary intervention (PCI) are well established (1,2). However, the appropriate response to resistance of anti-platelet therapy remains undefined. Because universal standards and universal definitions of resistance have not been established, conventional wisdom discourages routine testing for resistance or change of therapy based on resistance (3,4). The benefit of such testing in the setting of major adverse cardiac events (MACE) is perhaps more justified. Several studies, although small in sample size, suggest a correlation of MACE to anti-platelet therapy resistance (5–7).