Role of aspirin discontinuation in recurrence of ischemic cerebrovascular stroke

Serum thromboxane B2 but not soluble P-selectin levels identify ischemic stroke patients with persistent platelet reactivity while on aspirin therapy

BACKGROUND

Aspirin non-response due to persistent platelet reactivity has been associated with adverse vascular events. Light transmission aggregometry (LTA), the 'gold standard' for measuring the platelet response to aspirin therapy, is a cumbersome procedure and a simple and reliable alternative is required. Our aim was to explore whether serum thromboxane B2 (sTXB2) and soluble P-selectin can be used to identify patients who are at risk of increased platelet reactivity while on aspirin.

METHODS AND RESULTS

We recruited 293 ischemic stroke patients, taking aspirin for more than seven days, and performed LTA to classify them. Based on therapeutic serum salicylate levels, 63 patients were excluded due to suspected non-compliance, followed by ELISA measurement of TXB2 and P-selectin in serum. Accordingly, patients were classified into 'Responders' (n = 122, 53%), 'Semi-responders' (n = 76, 33%) and 'Non-responders' (n=32, 14%) by LTA. Patients who had platelet aggregation of ≥70% with 10μM ADP and ≥20% with 0.5mM AA were defined as 'Non-responders'. In comparison with 'Responders', 'Non-responders' had 8.63-fold increased risk of secondary vascular events (p = 0.008). ROC curve analysis revealed that sTXB2, at a cut-off level of >4.15 ng/mL, could distinguish the patient group with elevated platelet reactivity with a sensitivity of 84.3% (AUC = 0.84), and was in fair agreement with the LTA-based classification of patients. Soluble P-selectin levels, on the other hand, had no discriminatory ability.

CONCLUSION

We suggest sTXB2 measurement as an alternative to the LTA approach for identifying aspirin-treated ischemic stroke patients who are at risk of enhanced platelet reactivity and subsequent vascular events.

Adherence to Antithrombotic Treatment and Ischemic Stroke Recurrence in Egypt and Germany: A Comparative Analysis

BACKGROUND

The burden of stroke weighs heavily in developing countries where recurrence rates clearly exceed that of developed countries. The impact of nonadherence to antithrombotic treatment within this context has been poorly investigated.

OBJECTIVE

The objective of this study was to evaluate patients with recurrent ischemic stroke in Egypt and Germany with focus on stroke subtype distribution and adherence to antithrombotic therapy.

METHODS

We conducted a comparative cross-sectional retrospective cohort study enrolling consecutive patients hospitalized for recurrent ischemic stroke in 2017 in 2 academic centers. Data were collected on demographics, risk factors, stroke subtypes, and medication adherence. Nonadherence to antithrombotic agents was analyzed at the time point of index stroke (recurrent stroke). Predictors of nonadherence were analyzed using logistic regression.

RESULTS

A total of 373 Egyptian and 468 German patients with ischemic stroke were included. The proportion of recurrent ischemic stroke among all patients was higher in the Egyptian cohort compared to the German cohort (33 vs. 10%, p < 0.05). Small-vessel occlusion stroke was the most frequent subtype in Egyptians, with a significantly greater proportion than in Germans (45 vs. 26%, p < 0.05). Nonadherence to antiplatelets at the time point of the recurrent stroke was higher in Egyptians than in Germans (82 vs. 19%, p < 0.001). Low educational attainment among Egyptians (OR 0.14, 95% CI [0.00-0.19], p < 0.01) and high comorbidity scores among Germans (OR 2.45, 95% CI [1.06-5.66], p < 0.05) were found to be predictors of nonadherence to antithrombotic treatment.

CONCLUSIONS

The large stroke recurrence burden in Egypt may be partly explained by differing adherence to secondary preventative antithrombotic pharmacotherapy. Predictors of medication nonadherence have to be addressed to reduce stroke recurrence disparities.