In a study published online by JAMA, Robert W. Yeh, M.D., M.Sc., of Beth Israel Deaconess Medical Center, Boston, and colleagues conducted a study to identify factors that would predict whether the expected benefit of reduced ischemia would outweigh the expected increase in bleeding associated with continued dual antiplatelet therapy (aspirin plus thienopyridine) more than one year after coronary stent placement.
Dual antiplatelet therapy after percutaneous coronary intervention (PCI; commonly known as coronary angioplasty, a non-surgical procedure used to open narrow or blocked coronary arteries) reduces ischemia (inadequate blood supply to an area due to blockage of blood vessels leading to that area) but increases risk of bleeding. It remains unclear which patients are at high risk for late ischemic events and may thus benefit most from longer-term dual antiplatelet therapy vs those who are at high risk for late bleeding events and may be harmed.
Among 11,648 randomized DAPT (Dual Antiplatelet Therapy) Study patients from 11 countries, a prediction rule was derived stratifying patients into groups to distinguish ischemic and bleeding risk 12 to 30 months after PCI. The clinical prediction score was validated among 8,136 patients from 36 countries randomized in the PROTECT (Patient Related Outcomes With Endeavor vs Cypher Stenting) trial.
After adding or subtracting points for patients for factors such as heart attack at presentation, prior heart attack or PCI; diabetes; smoking; and older age, the researchers developed a clinical prediction score that showed modest accuracy assessing ischemic and bleeding risks.
"Use of this prediction score should be cautious until further validation is performed, and optimal clinical and procedural care to reduce overall bleeding and ischemic risks should be practiced independent of score," the authors write.