High Platelet Reactivity on Clopidogrel Therapy Correlates With Increased Coronary Atherosclerosis and Calcification
JACC Cardiovascular Imaging, 05/22/2012
Chirumamilla AP et al. – Increased platelet reactivity on clopidogrel treatment, defined as >230 platelet reactivity functional assay (P2Y12) reaction units, is associated with greater coronary artery atherosclerotic disease burden and plaque calcification.Methods
- This study included patients who underwent PCI with pre–intervention IVUS imaging and platelet reactivity functional assay (P2Y12 reaction units) performed >16 h after PCI, after the stabilization of clopidogrel therapy (administered before PCI).
- Platelet reactivity >230 P2Y12 reaction units defined high on–treatment platelet reactivity (HPR).
- Among 335 patients (mean age 65.0 years, 71% men), there were 109 patients with HPR (32.5%) and 226 without HPR (67.5%), with HPR being associated with diabetes and chronic renal insufficiency.
- By IVUS analysis, patients with HPR had significantly greater target lesion calcium lengths, calcium arcs, and calcium indexes.
- Furthermore, patients with HPR tended to have longer lesions and greater volumetric dimensions, indicating higher plaque volume, larger total vessel volume, and also greater luminal volume, despite similar plaque burden.
- By multivariate analysis controlling for baseline clinical variables, HPR was the single consistent predictor of all IVUS parameters examined, including plaque volume, calcium length, and calcium arc.