title: Relation between platelet response to exercise and coronary angiographic findings in patients with effort angina.
abstract: BACKGROUND
  Platelet reactivity is increased by exercise in patients with obstructive coronary artery disease (CAD) but not in patients with syndrome X. In this study, we prospectively investigated whether the platelet response to exercise might help distinguish, among patients with angina, those with obstructive CAD from those with normal coronary arteries (NCAs).
  
  
  RESULTS
  Venous blood samples were collected before and 5 minutes after exercise from 194 consecutive patients with stable angina. Platelet reactivity was measured by the platelet function analyzer (PFA)-100 system as the time for flowing whole blood to occlude a collagen-adenosine diphosphate ring (closure time). Coronary angiography showed CAD in 163 patients (84%) and NCA in 31 patients (16%). Baseline closure time was shorter in NCA patients (78.0+/-16 versus 95.5+/-23 seconds, P<0.0001). With exercise, closure time decreased in CAD patients (-15.5 seconds; 95% confidence limits [CL], -13.0 to -18.0 seconds; P<0.0001), but increased in NCA patients (12.5 seconds; 95% CL, 7.4 to 17.7 seconds; P=0.0004). An increase in closure time with exercise > or =10 seconds had 100% specificity and positive predictive value for NCAs. Similarly, a decrease > or =10 seconds had 100% specificity and positive predictive value for CAD. A closure time change (increase or decrease) > or =10 seconds allowed a correct classification of 55% of all patients.
  
  
  CONCLUSIONS
  Among patients with stable angina, the response of platelet reactivity to exercise was predictive of normal or stenosed coronary arteries at angiography. Specifically, an increase in closure time with exercise > or =10 seconds was invariably associated with the presence of NCA.
authors.affiliation: Istituto di Cardiologia, Università Cattolica del Sacro Cuore, Roma, Italy. g.a.lanza@inwind.it
authors.forename: Gaetano Antonio
authors.initials: GA
authors.lastname: Lanza
authors.forename: Alfonso
authors.initials: A
authors.lastname: Sestito
authors.forename: Sonia
authors.initials: S
authors.lastname: Iacovella
authors.forename: Laura
authors.initials: L
authors.lastname: Morlacchi
authors.forename: Enrico
authors.initials: E
authors.lastname: Romagnoli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Schiavoni
authors.forename: Filippo
authors.initials: F
authors.lastname: Crea
authors.forename: Attilio
authors.initials: A
authors.lastname: Maseri
authors.forename: Felicita
authors.initials: F
authors.lastname: Andreotti
mesh_terms: D000787:Angina Pectoris / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000175:diagnosis / Q000000981:diagnostic imaging; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation; D011446:Prospective Studies; D013577:Syndrome