METHODS: We did a retrospective observational cohort study. We included consecutive people with ACS who were discharged from Scottish hospitals between January 2008 and December 2013 and who received DAPT after discharge followed by antiplatelet monotherapy. The rates of cardiovascular events were assessed during each 90-day period of DAPT treatment and 90-day period after stopping DAPT. Cardiovascular events were defined as a composite of death, ACS, transient ischaemic attack or stroke. Cox regression was used to identify predictors of cardiovascular events following DAPT cessation.
RESULTS: 1340 patients were included (62% male, mean age 64.9 (13.0) years). Cardiovascular events occurred in 15.7% (n=211) during the DAPT period (mean DAPT duration 175.1 (155.3) days) and in 16.7% (n=188) following DAPT cessation (mean of 2.7 years follow-up). Independent predictors for a cardiovascular event following DAPT cessation were age (HR 1.07; 95% CI 1.05 to 1.08; p<0.001), DAPT duration (HR 0.997; 95% CI 0.995 to 0.998; p<0.001) and having revascularisation therapy during the index admission (HR 0.58; 95% CI 0.39 to 0.85; p=0.005).
CONCLUSIONS: The rate of cardiovascular events was not significantly increased in the early period post-DAPT cessation compared with later periods in this ACS population. Increasing age, DAPT duration and lack of revascularisation therapy were associated with increased risk of cardiovascular events during long-term follow-up after DAPT cessation.
METHODS: We used a matched case-control design using the Virtual International Stroke Trials Archive (VISTA). Cases were patients who had an acute coronary syndrome, recurrent stroke or transient ischaemic attack within 90 days post-stroke and were matched for age ± 10 years and sex with up to four controls. Antiplatelet use was categorized as persistent (used for >3 days and continued up to day 90), early cessation (used antiplatelet <3 days) or stopped/interrupted users (used for >3 days but stopped prior to day 90). These categories were compared in cases and controls using a conditional logistic regression model that adjusted for potential confounders.
RESULTS: A total of 970 patients were included, of whom 194 were cases and 776 were matched controls. At 90 days, 10 cases (5.2%) and 58 controls (7.5%) stopped/interrupted their antiplatelet. The risk of cardiovascular event was not different in stopped/interrupted users (adjusted odds ratio 0.70, 95% confidence interval 0.33, 1.48; P = 0.352) and early cessations (adjusted odds ratio 1.04, 95% confidence interval 0.62, 1.74; P = 0.876) when compared to persistent users.
CONCLUSION: We found no increased risk in patients who stopped and interrupted antiplatelets early after stroke but the study was limited by a small sample size and further research is needed.