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Published on: April 19, 2024
Activated partial thromboplastin time and clinical outcome after thrombin inhibition in unstable coronary artery
Insights
Higher activated partial thromboplastin time during inogatran treatment for unstable coronary artery disease correlates with increased adverse events. This highlights the need for defining optimal activated partial thromboplastin time ranges for direct thrombin inhibitors.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Direct thrombin inhibitors have not surpassed unfractionated heparin in treating unstable coronary artery disease.
- Investigating the link between activated partial thromboplastin time (aPTT) and clinical outcomes is crucial.
Purpose of the Study:
- To explore the relationship between aPTT levels and adverse clinical events in patients receiving inogatran or unfractionated heparin for unstable coronary artery disease.
Main Methods:
- A randomized trial involving 1209 patients with unstable coronary artery disease.
- Patients received either inogatran (a direct thrombin inhibitor) or unfractionated heparin for 72 hours.
- Adverse events (death, myocardial infarction, refractory angina) were monitored over 30 days.
Main Results:
- No significant difference in clinical outcomes between inogatran and unfractionated heparin groups over 30 days.
- Inogatran patients with aPTT above the median at 6 hours had a higher rate of clinical events within 7 days (11.6% vs 6.6%).
- A dose-dependent relationship was observed between higher aPTT levels and worse outcomes in the inogatran group, while heparin showed a trend towards improved outcomes with higher aPTT.
Conclusions:
- Elevated aPTT levels during inogatran therapy are associated with an increased risk of major adverse cardiovascular events.
- Optimal aPTT ranges for direct thrombin inhibitors in unstable coronary artery disease remain poorly defined, potentially due to differing anticoagulant mechanisms compared to heparin.
Unlabelled:
Aims Direct thrombin inhibitors have failed to prove superiority over unfractionated heparin in several clinical trials of unstable coronary artery disease. We have investigated the relationship between activated partial thromboplastin time levels and adverse clinical events, i.e. death, myocardial (re-)infarction or refractory angina. Methods and Results One thousand two hundred and nine patients with unstable coronary artery disease were randomized to 72 h infusion with inogatran, a low molecular mass direct thrombin inhibitor, or unfractionated heparin. During 30 days follow-up there was no significant difference between inogatran and unfractionated heparin treatment as regards clinical outcome. 11.6% of the 464 inogatran treated patients with activated partial thromboplastin time above the median at 6 h (44 s) had a clinical event in 7 days, and 6.6% of the 423 patients with activated partial thromboplastin time below the median (P=0.01). After 30 days the event rate was still 41% higher in the inogatran patients with activated partial thromboplastin time above the median (P=0.06). Activated partial thromboplastin time in quartiles indicated a direct relationship between higher activated partial thromboplastin time and worse outcome. In contrast, during heparin infusion there was a trend for improved clinical outcome with activated partial thromboplastin time above the median, but this benefit was lost after cessation of treatment.
Conclusions:
Higher activated partial thromboplastin time levels during inogatran treatment are related to increased risk of death, myocardial infarction or refractory angina. This might, at least in part, be explained by differences in anticoagulant mechanisms between direct thrombin inhibitors and heparin, and further emphasizes the poorly defined optimal activated partial thromboplastin time range during treatment with direct thrombin inhibitors in unstable coronary artery disease.
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