Clinical Trial Compares Safety of Blood Thinners

Overview of Heart Attack Risks

Heart attacks rank as the second leading cause of death in Canada. These critical events can stem from the development of blood clots in the coronary vessels, which supply blood to the heart. In many instances, clots may originate from other organs, travel through the bloodstream, and subsequently lodge in the coronary arteries.

Intervention Procedures and Challenges

When blood vessels become blocked by clots, cardiologists typically perform a procedure known as percutaneous coronary intervention (PCI) to restore blood flow. However, this procedure can pose significant risks in certain clinical situations, making it inadvisable in some cases. Additionally, the availability of professionals to conduct PCI in emergencies can be limited in various regions, leading clinicians to prescribe blood thinners to dissolve problematic clots.

Understanding Blood Thinners

Blood thinners, which can be either naturally occurring or synthetic, are designed to prevent, slow down, or obstruct the formation of blood clots. While they serve a critical function, their use carries the risk of unintended bleeding in patients, particularly in cases of accidents, such as bruising. Therefore, assessing the safety and efficacy of these medications is crucial.

Comparative Study of Ticagrelor and Clopidogrel

Details of the Clinical Trial

A recent clinical trial funded by Astra-Zeneca aimed to compare the safety profiles of two blood thinners: ticagrelor and clopidogrel. Ticagrelor functions by inhibiting platelet aggregation, a key initial step in the blood clotting process. The findings from this trial were presented at the American College of Cardiology’s 68th Annual Scientific Session held from March 16-18, 2019, in New Orleans, and were also published in the Journal of the American College of Cardiology.

Previous Research Insights

Earlier studies had shown ticagrelor to be superior to clopidogrel. The primary objective of this trial was to conduct a safety comparison between the two medications. Coordinated by the Research Institute – Heart Hospital (HCor) in São Paulo, Brazil, the trial involved over 3,800 patients from more than 180 medical centers across 10 countries on five continents, particularly focusing on lower-income nations where PCI availability is limited. Participants were randomly assigned to receive either ticagrelor or clopidogrel.

Findings on Safety and Efficacy

Researchers evaluated a composite score reflecting the rates of death from vascular complications, heart attacks, strokes, and other significant events 12 months post-treatment. The results indicated that ticagrelor had a safer profile compared to clopidogrel, with event rates of 8% for ticagrelor versus 9.1% for clopidogrel. This 1% difference suggested that clopidogrel has a comparable safety profile to ticagrelor.

Additionally, the researchers assessed the incidence of major bleeding events for both groups, which showed a similar rate, differing by only 1%. The positive outcomes from this trial suggest that alternative and safe options may be available for managing heart attacks related to blood clots.

Conclusion

The findings of this trial contribute valuable insights into the ongoing development of blood thinners, highlighting the importance of safety in clinical decisions for heart attack management.

Author Information

Written by Vinayak Khattar, Ph.D., M.B.A.

Reference

Berwanger, O., Lopes, R. D., Moia, D. D. F., Fonseca, F. A., Jiang, L., Goodman, S. G., . . . Nicolau, J. C. (2019). Ticagrelor versus Clopidogrel in Patients with STEMI Treated with Fibrinolytic Therapy: TREAT Trial. J Am Coll Cardiol. doi:10.1016/j.jacc.2019.03.011