Platelet Aggregability And Fibrinolytic Activity

s Background:Sexual dimorphism in coronary artery disease (CAD) mortality is attributed to the cardioprotective effects of estrogen.This is reinforced by the observation that incidence of myocardial infarction is higher in menstrual phase, corresponding with low estrogen levels, in people who are predisposed to CAD due to the presence of modifiable risk factors. Cyclical variability of estrogen and progesterone in normal menstruating women may be associated with variability of platelet aggregation and fibrinolytic activity.There exists a delicate balance between fibrinolytic activity and platelet aggregation governing the haemostatic status. Objectives:Platelet aggregability and fibrinolytic activity were measured and compared during menstrual (1-5 days), follicular ( 9-12 days) and luteal (20-25days) phases of menstrual cycle. Method:In this cross sectional study of 50 normal menstruating females in age group of 18-35yrs, Platelet aggregability was measured by ADP induced platelet aggregation on a spectrophotometer. Fibrinolytic activity was estimated by euglobulin clot lysis time. Results :Results were analyzed by students unpaired ‘t’ test. Change in platelet aggregability was found 0.12 ± 0.15, 0.04 ± 0.04 and 0.08 ± 0.07 in menstrual, follicular and luteal phase respectively. Platelet aggregability was found significantly (p < 0.001) higher in menstrual and luteal phases than follicular phase. The mean euglobulin clot lysis time was found 277.6 ± 43.96, 147.6 ± 52.78 and 244.6 ± 59.12 in menstrual, follicular and luteal phase respectively. Fibrinolytic activity was found significantly (p < 0.0001) lower in menstrual and luteal phases than follicular phase. Conclusion :According to the present study, in both luteal and menstrual phases, not only platelet aggregability was found higher, but fibrinolytic activity was also found lower as compared to follicular phase, thereby pointing towards thrombotic tendency in these phases. Hence, these phases require careful monitoring in women who are susceptible to thrombotic disorders. However, follicular phase with lower platelet aggregability and higher fibrinolytic activity is relatively free from thrombotic risk. [ Gaule A NJIRM 2012; 3(4) :80-85]