Could platelet aggregation ratio be an indicator for differential diagnosis of transient ischemic attack and cerebral ischemic stroke?

Background: Platelet aggregation plays an important role in the pathogenesis of thromboembolic cerebrovascular disease. Platelet aggregation ratio (PAR) and its derivates have been used successfully to identify the effectiveness of antiplatelet agents and their optimum dosage in patients suffering from stroke. However, we failed to find any study using PAR as a predictive factor in differential diagnosis of ischemic cerebrovascular diseases. In this study, we aimed to investigate PAR in patients with acute ischemic stroke and transient ischemic attack (TIA), comparing their neuroradiological features, and whether PAR values could be an indicator for differential diagnosis of TIA and cerebral ischemic stroke.

Methods: The study consisted of 75 adult patients who were admitted with suspected stroke and 25 control healthy individuals. All patients were diagnosed with acute ischemic stroke or TIA and the diagnoses were confirmed by clinical examination and computed tomography (CT). The stroke group consisted of 45, and the TIA group of 30 consecutive patients. The patients included in this study had noncardioembolic stroke. PAR values were measured on admission in all groups, according to the modified method of Wu and Hoak. The statistical significance of differences was evaluated using one-way ANOVA, the unpaired Student t test and the Bonferroni and Tamhane post hoc tests.

Results: Differences in PARs between the control and TIA groups, control and stroke groups and stroke and TIA groups were significant (p < 0.001). Nevertheless, in each group, differences between genders were not statistically significant. Initial CT scan demonstrated early infarction sign in 26 stroke patients (57%); however, in 19 stroke patients, it was not detected. Differences in PARs between TIA and stroke patients, whose initial CT scan findings were negative, were found to be significant. However, differences in PARs between CT negative stroke patients and positive stroke patients were not significant.

Conclusion: We believe that the use of PAR values in the assessment of acute ischemic stroke and TIA could open up a new perspective in the management of such patients. In differential diagnosis, PAR values have to combine with neurological examination and CT scan signs. The current test is not able to differentiate vascular occlusive diseases in other organs from vascular occlusive problems in the brain. Further study is needed to determine the sensitivity and specificity of this test in all patients and to confirm the prognostic value in stroke patients.