Effects of nonspecific -adrenergic stimulation and blockade on blood coagulation in hypertension

von Känel, Roland, Joel E. Dimsdale, Karen A. Adler, Elaine Dillon, Christy J. Perez, and Paul J. Mills. Effects of nonspecific -adrenergic stimulation and blockade on blood coagulation in hypertension. J Appl Physiol 94: 1455–1459, 2003. First published December 13, 2002; 10.1152/japplphysiol.00892.2002.—A hypercoagulable state might contribute to increased atherothrombotic risk in hypertension. The sympathetic nervous system is hyperactive in hypertension, and it regulates hemostatic function. We investigated the effect of nonspecific -adrenergic stimulation (isoproterenol) and blockade (propranolol) on clotting diathesis in hypertension. Fifteen hypertensive and 21 normotensive subjects underwent isoproterenol infusion in two sequential, fixed-order doses of 20 and then 40 ng kg 1 min 1 for 15 min/dose. Thirteen subjects were double-blind studied after receiving placebo or propranolol (100 mg/day) for 5 days each. In hypertensive subjects, isoproterenol elicited a dose-dependent increase in plasma von Willebrand factor (vWF) antigen [F(2,34) 5.02; P 0.032] and a decrease in D-dimer [F(2,34) 4.57; P 0.040], whereas soluble tissue factor remained unchanged. Propranolol completely abolished the increase in vWF elicited by isoproterenol [F(1,12) 10.25; P 0.008] but had no significant effect on tissue factor and D-dimer. In hypertension, vWF is readily released from endothelial cells by -adrenergic stimulation, which might contribute to increased cardiovascular risk. However, -adrenergic stimulation alone may not be sufficient to trigger fibrin formation in vivo.