Aspirin-Resistant Thromboxane Biosynthesis and the Risk of Myocardial Infarction, Stroke, or Cardiovascular Death in Patients at High Risk for Cardiovascular Events
Key result
Higher urinary 11-dehydro thromboxane B2 linked to ~80% greater risk of major CV events on aspirin.
- OR 1.8
- 95% CI 1.2 to 2.7
- P=0.009
- n=976
Why the study?
It was uncertain whether aspirin resistance, defined by failure to suppress thromboxane generation, increases cardiovascular event risk in high-risk patients.
Does elevated urinary 11-dehydro thromboxane B2 (aspirin resistance) increase the risk of myocardial infarction, stroke, or cardiovascular death in high-risk patients treated with aspirin?
Comparison
Upper quartile vs lower quartile of urinary 11-dehydro thromboxane B2 levels
Design
Nested case-control study
Follow-up
5 years
Authors
Discussion
Loading...
Member takes
Implication
Should not yet change aspirin therapy; leaves open whether 11-dehydro thromboxane B2 identifies modifiable risk.
Study Design
Type
Case-Control (n=976)
Structured PICO
Does elevated urinary 11-dehydro thromboxane B2 (aspirin resistance) increase the risk of myocardial infarction, stroke, or cardiovascular death in high-risk patients treated with aspirin?
P
Population
976 Canadian patients (488 cases, 488 sex- and age-matched controls) treated with aspirin, at high risk for cardiovascular events, enrolled in the HOPE Study.
I
Intervention
Upper quartile of urinary 11-dehydro thromboxane B2 levels (marker of in vivo thromboxane generation)
C
Comparator
Lower quartile of urinary 11-dehydro thromboxane B2 levels
O
Outcome
Composite of myocardial infarction, stroke, or cardiovascular death during 5 years of follow-upcomposite
Main Result
Effect estimate: OR 1.8 (95% CI 1.2 to 2.7)
p-value: p=0.009
Elevated urinary 11-dehydro thromboxane B2 levels in aspirin-treated patients predict a higher risk of future myocardial infarction or cardiovascular death, suggesting aspirin resistance.
Cite This Study
Eikelboom et al. (2002) conducted a case-control in High risk for cardiovascular events (n=976). Upper quartile of urinary 11-dehydro thromboxane B2 vs. Lower quartile of urinary 11-dehydro thromboxane B2 was evaluated on Composite outcome of myocardial infarction, stroke, or cardiovascular death (OR 1.8, 95% CI 1.2 to 2.7, p=0.009). Aspirin-treated patients in the upper quartile of urinary 11-dehydro thromboxane B2 had a higher risk of MI, stroke, or CV death than those in the lower quartile (OR 1.8; 95% CI 1.2-2.7; P=0.009).