Thromboxane and prostacyclin biosynthesis in patients with acute spontaneous intracerebral hemorrhage

Elevated levels of 11-dehydrothromboxane B2 (11-dehydro-TXB2) excreted in urine have been observed in acute ischemic stroke. This marker of platelet activation has not been investigated in patients with acute spontaneous intracerebral hemorrhage (ICH).

We examined 43 patients with spontaneous ICH and 23 controls. Urinary excretion rates of 11-dehydro-TXB2, 2,3-dinor-thromboxane B2 (2,3 dinor-TXB2) and 2,3-dinor-6-ketoprostaglandin F(1alpha) (2,3-dinor-PGF(1alpha)) during the first week and at 3 months after ICH were compared between patients who had or had not used aspirin and controls.

On admission, ICH patients without aspirin use had significantly higher urinary levels of 11-dehydro-TXB2 (p<0.001), 2,3-dinor-TXB2 (p<0.001) and 2,3-dinor-PGF(1alpha) (p=0.019) than controls. Aspirin users had significantly lower urinary levels of these metabolites than nonusers. The metabolite levels of aspirin users on admission did not significantly differ from those of controls. The differences between aspirin users and nonusers leveled off during the following 3-5 days, however, as the blocking effect of aspirin on the production of TXA2 and PGI2 ceased. Three months after ICH, the metabolite excretion levels in all the patients were similar to those in nonusers of aspirin on admission. On admission, aspirin users had longer bleeding times (p=0.032) than nonusers, but aspirin use did not associate with impaired recovery or hematoma enlargement.

Urinary excretion levels of 11-dehydro-TXB2, 2,3-dinor-TXB2 and 2,3-dinor-PGF1alpha were higher in patients with acute ICH than in controls. The levels in aspirin users were equally low as in controls but rose to the levels of the other patients within a few days. The metabolite levels remained high 3 months after ICH in all patients. Prior use of aspirin did not seem to cause hematoma enlargement.