NEW YORK (Reuters Health) – Silent embolic cerebral infarctions occur in about 1 in 6 patients after undergoing coronary angiography, and the risk is related to the degree of platelet inhibition with aspirin and clopidogrel, a Korean study shows.
The findings are reported by Dr. Sun U. Kwon and colleagues at the University of Ulsan College of Medicine, Seoul, in the December 29 online issue of Stroke.
“Measurement of platelet inhibition may predict SECI (silent embolic cerebral infarctions) occurring after CAG (coronary angiography),” they advise, “and increasing the dose of antiplatelet agents in the patients with insufficient platelet inhibition may be helpful in prevention.”
The team notes that while SECI are asymptomatic by routine neurologic evaluation, more extensive examinations have tied them to significant post-catheterization cognitive impairment. They hypothesized that the risk of SECI after coronary angiography might be related to insufficient platelet inhibition during the procedure.
To investigate, they first performed a retrospective study of 272 patients undergoing coronary angiography before coronary artery bypass grafting and who had diffusion-weighted imaging studies as a presurgical evaluation. All patients received standard antiplatelet therapy with aspirin and clopidogrel before and during angiography.
SECI were seen on the MRIs in 16.5% of these patients, mostly in the cerebral cortex. The WBC was significantly higher in the group with SECI, the researchers found.
They then conducted a prospective study involving 102 similar patients, measuring platelet inhibition within 6 hours after coronary angiography using the VerifyNow Aspirin and VerifyNow P2Y12 systems.
In this cohort, the overall prevalence of SECI was 16.7%, but the rate varied with the extent of platelet inhibition: it was 50% with resistance to both aspirin and clopidogrel, 22% with resistance to one agent, and 4% with no resistance to either drug, according to the report.
Given these results, Dr. Kwon and colleagues conclude that increasing platelet inhibition with higher doses of antiplatelet agents can reduce the occurrence of SECI – but this may increase bleeding risks. “Therefore,” they suggest, “measuring resistance of antiplatelet agents and selectively administering a high dose to patients with resistance may be a more logical option to reduce the occurrence of SECI after CAG.”
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