At the present time, the evidence base is insufficient to recommend routine platelet function testing. The results of 2 ongoing trials (DANTE [Dual Antiplatelet Therapy Tailored on the Extent of Platelet Inhibition] and ARCTIC [Double Randomization of a Monitoring Adjusted Antiplatelet Treatment Versus a Common Antiplatelet Treat- ment for DES Implantation, and Interruption Versus Contin- uation of Double Antiplatelet Therapy, One Year After Stenting]) will provide further information on the issue (www.clinicaltrials.gov). 6.2. Stent Thrombosis The majority of stent thrombosis occurs early (0 to 30 days after PCI). In broad clinical practice, the expected rate of early stent thrombosis is 1%, and beyond 30 days it is 0.2% to 0.6% per year.210,831 Acute stent thrombosis often presents as STEMI, and emergency revascularization is indicated. Acute stent thrombosis is associated with mortality rates of 20% to 45%.832 Survivors are also at risk of recurrent stent Mechanical and pharmacological factors are the most frequent cause of acute stent thrombosis. After the usual measures to restore flow in the infarct-related artery, it is important to consider the etiology of stent thrombosis as it pertains to further therapy and avoidance of recurrence. IVUS may identify factors such as an undersized stent, incomplete stent apposition, residual stenosis, or dissection and can guide subsequent treatment. The most common cause of acute stent thrombosis is nonadherence to DAPT; however, resistance to aspirin or thienopyridines and prothrombotic states such as congenital or acquired thrombophilic states (malignancy) are additional risk factors.834,835 Given the poor prognosis of stent thrombosis and the uncertainties surrounding treatment, the importance of pre- vention must be emphasized. This includes ensuring compli- ance with DAPT and adequate stent sizing and expansion.836 6.3. Restenosis: Recommendations Class I 1. 