Traditional clinical risk factors predict clopidogrel hypo-responsiveness in unselected patients undergoing non-emergent percutaneous coronary intervention

High and low platelet reactivity, HPR and LPR respectively, to clopidogrel and aspirin have previously been associated with adverse events following percutaneous coronary intervention (PCI). The aim is to test the ability of a previously developed clinical risk-score, the PREDICT score, to identify patients with HPR and LPR. Nine hundred and twenty-three consecutive patients undergoing non-emergent PCI were enrolled. Platelet reactivity (PR) was determined using Multiplate assays. Patients were grouped into quintiles based on their PR values. Upper and lower quintiles defined HPR and LPR, respectively, whereas quintiles 2-4 defined normal responders. All patients were assigned PREDICT score points in clinical categories (age > 65, reduced left ventricular function, reduced kidney function, acute coronary syndrome (ACS) and diabetes). We found an association between the cumulative number of PREDICT score variables and the incidence of HPR for clopidogrel (HPR (ADP)) (p < 0.001) and aspirin (HPR (AA)) (p = 0.007). In addition, the higher the PREDICT score, the higher the risk of HPR (ADP) (1-3 points, odds ratio (OR) 3.82 (95% CI 1.5-9.73, p = 0.005); 4-6 points OR 4.11 (95% CI 1.61-10.52, p = 0.003); 7-9 points OR 9.84 (95% CI 3.49-27.7, p < 0.001); patients with 0 PREDICT points defined the reference population). The relation was reversed with regards to clopidogrel LPR (LPR (ADP)). On the other hand, there was no clear association between PREDICT score and AA response. The PREDICT score was able to identify patients with a high risk of HPR (ADP) but did not correlate well with PR to AA. In order to assure an optimal tailoring of antiplatelet therapy, costly platelet function tests (PFTs) could be reserved for patients with high clinical likelihood for HPR.