The interactive effects of Type A behavior and hostility on bleeding time thromboxane and prostacyclin formation.

Sixty-six male university students were classified as Type A or B on the basis of the Structured Interview of Rosenman and as hostile or non-hostile on the basis of the Cook-Medley scale. Vascular production of prostacyclin and platelet thromboxane in response to a standard vessel injury was evaluated. Basal thromboxane production, measured as the primary metabolite, thromboxane B2, in blood oozing from the bleeding-time site, was highest among hostile Type A subjects with significantly lower thromboxane production in hostile Type Bs and all non-hostile groups combined. Following an exercise treadmill test hostile subjects produced more thromboxane than non-hostile ones, and hostile Type As had significantly shorter bleeding times than hostile Type Bs. No significant differences on any measure were observed following a stressful color naming task. The observed interaction of hostility and Type A behavior on bleeding time thromboxane formation links behavior to an adverse aspect of a thrombosis-related parameter thought to be involved in the genesis of cardiovascular disease.