Plasma fibrin clot properties in arterial hypertension and their modification by antihypertensive medication.

We sought to determine plasma fibrin clot properties in hypertensive subjects and to evaluate potential effects of antihypertensive therapy on these parameters. Sixty-one patients (30 men, 31 women) with essential arterial hypertension stage 1 or 2 (aged 46.6 ± 14.4 years), free of clinically evident vascular disease, were randomly allocated for monotherapy with one of the 5 antihypertensive agents, i.e. quinapril, losartan, amlodipine, hydrochlorothiazide, or bisoprolol. Plasma fibrin clot permeability, turbidimetry and efficiency of fibrinolysis were investigated at baseline and after 6 months of therapy. Baseline systolic blood pressure in a 24-hour ambulatory monitoring was correlated with clot permeability (r=-0.37, p<0.05), lysis time (r=0.42, p<0.05) and maximal D-dimer concentration released from clots (r=0.45, p<0.05). Antihypertensive treatment resulted in reduction of systolic/diastolic blood pressure in office measurements and 24-hour monitoring (all p<0.001), accompanied by an increase in clot permeability, reduction in clot lysis time and lower maximal D-dimer concentration released from fibrin clots (all p<0.05). No changes were observed in turbidimetric variables. Posttreatment changes in plasma fibrin clot properties were related to reductions in systolic blood pressure, complement component C3 and total cholesterol. Reduction in systolic blood pressure during antihypertensive treatment leads to increased plasma fibrin clot permeation and susceptibility to lysis, which might be a novel antithrombotic mechanism of blood pressure lowering therapy.