The impaired fibrinolytic capacity in hypertension is unaffected by acute blood pressure lowering

The endogenous fibrinolytic system and the ability of the endothelium to release tissue-plasminogen activator (t-PA) play a pivotal role to protect humans from atherothrombotic events. We have recently reported that the decreased capacity for t-PA release in hypertension is restored with chronic blood pressure lowering. Thus, we explored if acute blood pressure lowering has the same effect. The capacity for acute t-PA release was investigated in the perfused-forearm model during stimulation by intra-arterial substance P 8 pmol/min in hypertensive subjects. The procedure was then repeated during acute blood pressure lowering ( n = 9) induced by sodium nitroprusside (SNP) infusion or during placebo infusion ( n = 3). SNP lowered mean arterial pressure from 108.6 (2.6) to 83.0 (2.6) (mean and SEM) mmHg ( P