INFLUENCE OF PLATELET SIZE BEFORE CORONARY ANGIOPLASTY ON SUBSEQUENT RESTENOSIS

Platelet size has been shown to reflect platelet activity. We prospect ively measured the mean platelet volume (MPV) in 47 patients undergoin g single vessel angioplasty for symptomatic angina. The patients under went repeat angiography 4-8 months later irrespective of symptomatic s tatus. Restenosis was assessed quantitatively by hand held calliper me asurements of the lesion and qualitatively by a return of angina, ST s egment changes on an exercise test and visual analysis of the lesion s everity by two experienced angiographers. Twenty-four patients develop ed recurrent angina during the follow-up period, the MPV in the group with chest pain was 8.54 +/- 0.60 fl compared to 8.1 +/- 0.69 fl in th e asymptomatic group (P = 0.04). Twenty two patients had significant S T segment changes at exercise. In this group the MPV was 8.6 +/- 0.56 fl compared to 8.0 +/- 0.70 fl for the group with a negative test (P = 0.002). Similarly visually assessed angiographic stenosis showed a si gnificant increase in the restenotic group (8.6 +/- 0.56 vs. 8.0 +/- 0 .61 fl, P = 0.001). The relative odds for developing clinically define d restenosis were 10.2 times greater if the pre-procedural MPV lay in the upper compared to the lowest quartile. There was a positive correl ation between MPV and change in minimal luminal diameter between post angioplasty and follow-up angiography, assessed quantitatively, r= +0. 56, P = 0.016. There was no association between clinical or angiograph ic definitions of restenosis and haemoglobin, red cell count, mean cor puscular volume, white cell count or platelet count. Platelet size may influence the development of restenosis after succeesful coronary ang ioplasty.