PLATELET ACTIVATION MARKERS IN PATIENTS WITH PERIPHERAL ARTERIAL-DISEASE - A PROSPECTIVE COMPARISON OF DIFFERENT PLATELET-FUNCTION TESTS

Peripheral vascular disease (PVD) is an indicator of diffuse atheroscl erosis and is associated with a greatly increased incidence of coronar y heart and cerebrovascular disease. Although several studies have ass essed whether in vivo platelet activation takes place in patients with PVD, no data are available comparing different platelet function test s in this patient population. We have compared prospectively four test s for the measurement of in vivo platelet activation (plasma beta TG, plasma PF4, intraplatelet beta TG and urinary excretion of 11-dehydro- TXB2) and one in vitro platelet function test (ADP-induced platelet ag gregation) in 63 well-characterized patients with intermittent claudic ation and in 18 age- and sex-matched healthy volunteers. No statistica lly significant difference was found between patients and controls for plasma beta TG (20.0 +/- 11.8 vs. 18.8 +/- 9.0 ng/ml, respectively), plasma PF4 (5.2 +/- 2.9 vs. 6.3 +/- 3.5 ng/ml), beta TG/PF4 ratio (4.0 +/- 2.9 vs. 3.6 +/- 1.8), intraplatelet beta TG (4503 +/- 1482 vs. 40 59 +/- 1065 ng/ml), and threshold aggregatory concentration of ADP (1. 7 +/- 0.72 vs. 1.45 +/- 0.56 mu M). Urinary 11-dehydro-TXB2 was instea d significantly higher in the PVD group (55.4 +/- 27.5 vs. 26.7 +/- 7. 0 ng/h, p <0.001). Our study shows that urinary 11-dehydro-TXB2 is a m ore sensitive index of in vivo platelet activation than the measuremen t of either platelet specific proteins or of in vitro platelet aggrega tion in patients with PVD.