Instant subacute stent thrombosis after maximum-load cardiopulmonary exercise test in a clopidogrel poor metabolizer with acute coronary syndrome.

A 63-year-old man with a hobby of full marathon and triathlon fainted while commuting on a 25-km one-way bicycle trip and was admitted to the hospital after return of spontaneous circulation. The patient was diagnosed with acute coronary syndrome, and contrast-enhanced computed tomography for trauma diagnosis indicated suspicion of liver injury. Although coronary angiography revealed a severe stenotic lesion in the left anterior descending artery, percutaneous coronary intervention (PCI) was deferred because of thrombolysis in myocardial infarction grade 3 flow. Following neurological recovery, the patient was started on dual antiplatelet therapy (aspirin and clopidogrel). On day 11, a 3.0/34-mm Resolute Onyx stent (Medtronic, Dublin, Ireland) was deployed following rotablation. As a pre-discharge evaluation, a maximum-load cardiopulmonary exercise test was performed 8 days after PCI. However, the patient developed stent thrombosis after 2 h. Subsequently, the patient was diagnosed as a clopidogrel poor metabolizer using a blood test. Learning objective: Existing guidelines recommend a cardiopulmonary exercise test (CPET) before or immediately after the discharge of patients with acute coronary syndrome (ACS). However, the safety of the maximum-load CPET has not been established, especially in clopidogrel poor metabolizers with ACS. Acute maximal exercise induces platelet aggregation; therefore, further discussion is needed regarding the timing of CPET, exercise load level, and patient observation post-CPET in ACS patients after stent placement.