RELATIONSHIPS OF BLOOD-PRESSURE TO FIBRINOLYSIS - INFLUENCE OF ANTHROPOMETRY, METABOLIC PROFILE AND BEHAVIORAL VARIABLES

Objective: To investigate the relationship between blood pressure and the plasma fibrinolytic system and to verify whether this association was independent or mediated by one or more potential confounding facto r. Design: A random sample of 94 males aged 38 years subdivided into n ormotensives, hypertensives and those hypertensives with the highest b lood pressure values. Methods: Overall and regional obesity, blood lip ids, fasting and 2-h post-load glucose, C-peptide and insulin levels, and main behavioural variables, including adipose tissue fatty acid co mposition (an objective index of dietary fat intake), were measured. T he plasma fibrinolytic system was evaluated by determining activities and total plasma concentrations of both tissue-type plasminogen activa tor before and after venous occlusion, and its inhibitor plasminogen a ctivator inhibitor type-1 (PAI-1). Results: PAI-1 activity was signifi cantly higher in the hypertensives than in the normotensives. PAI-1 an tigen tended to parallel PAI-1 activity, and levels of tissue-type pla sminogen activator antigen and activity tended to be lower in the hype rtensives at baseline and after venous occlusion, but not significantl y different from those in the normotensives. The hypertensives also ha d significantly higher body mass index and body fat content (measured by bio-impedance), increased plasma triglycerides, uric acid, fasting and 2-h glucose, C-peptide and insulin concentrations. In univariate l inear regression analysis both systolic and diastolic blood pressures were found to be positively correlated with PAI-1 levels (r = 0.27, P< 0.01, for both). This correlation was maintained after adjustment for total body fat, fasting glucose, fasting insulin concentration or adi pose tissue alpha-linolenic acid; however, it was no longer significan t after adjustment for plasma 2-h insulin, 2-h C-peptide, 2-h glucose or triglyceride levels. Multivariate regression analysis revealed that only 2-h insulin and triglyceride concentration showed an independent association with PAI-1 levels. Conclusions: This study confirms that, in 38-year-old males, hypertension is associated with increased PAI-1 activity. It supports the possibility that the relationship between b lood pressure and PAI-1 may reflect the overall effect of the insulin resistance syndrome (in particular hyperinsulinaemia and hypertriglyce ridaemia) rather than a direct effect of blood pressure on the fibrino lytic system.