AUTHOR=Hegde Nischal N. , Mathew Navin , Thachathodiyl Rajesh , Menon Jaideep C. 

TITLE=Personalized allocation of acetylsalicylic acid therapy for secondary prevention of coronary artery disease

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.1004473

DOI=10.3389/fcvm.2022.1004473

ISSN=2297-055X

ABSTRACT=Single daily dose of 75mg acetylsalicylic-acid inhibits 100% of thromboxane-B2 synthesis within 30-60 minutes. Thromboxane-B2 synthesis recovers slowly as new platelets are released from the bone marrow. Normally, only 10% of the platelets are replaced daily by new platelets. Hence, 24-hours after a dose of acetylsalicylic-acid, thromboxane-B2 synthesis is still suppressed by more than 90%. Hence, there is adequate anti-platelet effect even after 24-hours of acetylsalicylic-acid intake. However, some patients treated with once-daily acetylsalicylic acid may have an incomplete 24-hour suppression of thromboxane-B2 synthesis due to increased platelet turnover. The response could be improved in such patients by twice-daily acetylsalicylic-acid administration. This study aimed to identify such a group of patients who would benefit from twice-daily dose of acetylsalicylic-acid.

Methods
Serum thromboxane-B2 levels were measured, in 79 patients with coronary artery
disease receiving 75 mg of acetylsalicylic-acid for secondary prophylaxis. Serum levels of thromboxane-B2 were measured after 4-hours and 24-hours of acetylsalicylic-acid intake. Patients were classified into three groups: Steady suppression group (Serum thromboxane B2 is adequately suppressed at 4-and 24-hours) i.e., adequate response to acetylsalicylic acid; Fast recovery group (More than 10% rise in serum thromboxane-B2 levels at 24-hours when compared to at 4-hours) and Non-responders (Serum thromboxane-B2 levels of >3100 pg/ml after 4 hours of acetylsalicylic acid intake). Patients in the fast-recovery group were given twice-daily acetylsalicylic acid and thromboxane-B2 levels were re-measured.

Results
20 patients (24.3%) of the patient had stead-suppression of thromboxane-B2. 11
patients (13.9%) belonged to fast-recovery group, i.e., Thromboxane-B2 levels were
adequately suppressed at 4-hours but had recovered by more than 10% at 24 hours; which was adequately suppressed by twice-daily acetylsalicylic-acid (p 0.004). 48 patients (60.8%) were non-responders.

Conclusion
Twice-daily acetylsalicylic acid maybe beneficial if serum thromboxane-B2 levels at 4-hours is <3100pg/ml and is >3100 pg/ml at 24-hours. If thromboxane-B2 levels at 4 and 24-hours is <3100 pg/ml but if there is a >10% rise in serum thromboxane B2 at 24-hours as compared to that at 4-hours then twice-daily acetylsalicylic acid should be considered. However, if thromboxane-B2 at 4 hours and 24-hours is > 3100 pg/ml consider switching over to a P2Y12 inhibitor.