1995 Volume 17 Issue 3 Pages 298-305
It has been reported that abnormalities of systemic coagulation, such as platelet hyperaggregation and hypercoagulation, occur together with vasospasm after aneurysmal subarachnoid hemorrhage (SAH). We evaluated the hemorheological effects of ticlopidine as a means of preventing symptomatic vasospasm. Experimentally, SAH was induced by a single injection of 5 ml of autologous arterial blood into the cisterna magna of hybrid dogs weighing 10-15 kg. The hemorhelogical effects of ticlopidine (100 mg/kg) were determined by examining the platelet aggregation (optical density method), fibrinogen, fibrin/fibrinogen degradation products (FDP), streptokinase-euglobulin lysis time (SK-ELT) and morphological changes in red blood cells and platelets from pre-SAH to the 5th day after SAH. Clinically, we investigated 139 aneurysmal patients admitted within 72 hours after SAH to assess the efficacy of ticlopidine for preventing symptomatic vasospasm. Hemorheological analysis of vasospasm was performed by examining the platelet aggregation using a screen filtration pressure method, platelet counts, fibrinogen, FDP and SK-ELT. In this series, 102 patients (group A) were treated with a regimen that included ticlopidine, and 50 of them were operated on at the early stage; 37 patients (group B) were treated without ticlopidine. Experimental studies demonstrated that ticlopidine reduced platelet hyperaggregation and morphological changes in red blood cells and platelets after SAH. The incidence of symptomatic vasospasm was 33% in group A, 30% in the subgroup of group A that underwent early-stage surgery, and 65% in group B. Fatal vasospasm was significantly less frequent in group A (6%) than in group B (32%). Surviving patients in groups A and B displayed normal or slightly high levels of platelet aggregation and low FDP, but patients who had fatal vasospasm showed low levels of platelet aggregation and high FDP, as observed in the intravascular coagulation syndrome. These results suggest that ciclopidine may be useful for the prevention of symptomatic vasospasm, increasing the proportion of good outcomes. Typical abnormalities of blood coagulation appearing in the acute stage of SAH are closely related to fatal vasospasm and can be employed as an important indicator of prognosis.
