title: The role of exercise on platelet aggregation in patients with stable coronary artery disease: exercise induces aspirin resistant platelet activation.
abstract: OBJECTIVE
  The aim of our study was to determine the relation between exercise stress test and aspirin resistance in patients with stable coronary artery disease.
  
  
  BACKGROUND
  Clinically aspirin resistance is defined as having thrombotic and embolic cardiovascular events despite regular aspirin therapy.
  
  
  METHODS
  We studied platelet functions of 62 patients with stable coronary artery disease and 20 subjects with normal coronary arteries by Platelet Function Analyzer (PFA-100, Dade Behring, Germany) at rest and after exertion with collagen and/or epinephrine (Col/Epi) and collagen and/or ADP cartridges. Closure time (CT)<186 seconds was defined as aspirin resistance with Col/Epi cartridges of PFA-100. Symptom limited treadmill stress test (protocol of Bruce) was performed with Oxford Streslink TD-1 system.
  
  
  RESULTS
  8 (12.9%) patients were aspirin resistant by PFA-100 (CT<186s despite regular aspirin therapy) at rest. At the first minute of the recovery period of exercise stress test 14 (22.5%) patients were aspirin resistant by PFA-100. CTs with Col/ADP were respectively 89+/-6 s (83--100s) and 89+/-5 s (82--104s) at rest and after exercise (p=0.107). 20.3% (11/54) of patients known as in vitro aspirin sensitives at rest had shorter CTs and 11.1% (6/54) had aspirin resistance after exercise (p=0.004). There was no statistically significiant difference in platelet functions in the control group after exertion.
  
  
  CONCLUSIONS
  We conclude that 11.1% of in vitro aspirin sensitive subjects at rest had aspirin resistance after exercise by PFA-100. In some individuals, exercise induced platelet activation is aspirin insensitive at usual antiplatelet doses. We need further clinical trials to optimize antiplatelet therapy in patients with coronary artery disease.
authors.affiliation: Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey. bpamukcu@istanbul.edu.tr
authors.forename: Burak
authors.initials: B
authors.lastname: Pamukcu
authors.forename: Huseyin
authors.initials: H
authors.lastname: Oflaz
authors.forename: Rezzan Deniz
authors.initials: RD
authors.lastname: Acar
authors.forename: Sabahattin
authors.initials: S
authors.lastname: Umman
authors.forename: Nevres
authors.initials: N
authors.lastname: Koylan
authors.forename: Berrin
authors.initials: B
authors.lastname: Umman
authors.forename: Yilmaz
authors.initials: Y
authors.lastname: Nisanci
mesh_terms: D000328:Adult; D001241:Aspirin / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D003327:Coronary Disease / Q000503:physiopathology / Q000534:rehabilitation*; D004351:Drug Resistance; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000187:drug effects*; D010974:Platelet Aggregation / Q000502:physiology*; D012016:Reference Values
chemical_list: D001241:Aspirin