Abstract 14420: Prasugrel Treatment is More Effective in Reducing Platelet Reactivity in PCI Patients with Low Clopidogrel Response Compared to Ticagrelor or Dose Increase of Clopidogrel
Dual anti-platelet therapy is routine after PCI. Low response (LR) to thienopyridine treatment as determined by platelet function testing has been shown to be associated with a significantly increased risk for stent thrombosis and other ischemic events. In order to intensify the anti-platelet regimen patients can either be reloaded with Clopidogrel (CLO) with the subsequent increase of its daily dose to 150 mg/d or the treatment can be switched to prasugrel or ticagrelor.
Methods: Platelet function testing using multiple electrode aggregometry (Multiplate analyzer Roche©) was performed in 1257 patients undergoing PCI. Patients with LR to initial CLO loading dose (LD) (600mg) and standard daily treatment (SDT) (1x75mg) were either reloaded with 600 mg CLO and then treated with daily 150mg (CLO 150 n=70) or were immediately switched either to prasugrel (PRA) LD 60mg and SDT 1x10mg (n=76) or Ticagrelor (TICA) LD 180mg, SDT 2x90mg (n=84). We retrospectively analysed the platelet function in all groups. Aggregation was tested on the first 48 hours after PCI in hirudin blood after stimulation of platelets with 6.4 µM ADP and expressed in Units (U). Prospectively a cut-off point > 42U was defined as LR < 19 U was quantified as “high-response” (HR).
Results: In group CLO150 aggregation was 53±17 U (mean ± sd) before to 40±20 U (-23%) after reloading and therapy modification. 25 patients (36%) still showed LR, while only 4 (6%) fulfilled the criteria of a HR to CLO. In group PRA aggregation decreased from 61±17 U before to 26±12 U (-56%) vs. 57±14 U before to 32±14 U (-45%) in the TICA group (p<0,009). 7 patients showed LR under PRA treatment (9%) vs 11 pts (16%) under TICA treatment. 25 patients showed HR to PRA treatment (32%) vs 14 pts (17%). Patientgroups showed significantly different distribution of responselevels (LR/HR PRA/TICA (P=0,045), PRA-CLO <0,001, TICA-CLO 0,005).
Conclusions: Prasugrel is significantly more effective in achieving sufficient platelet inhibition in Clopidogrel LR compared to Ticagrelor or a dose increase of Clopidogrel dose (reduction of the average aggregation by 56% vs. 45% vs. 23%). However also a higher rate HR to prasugrel treatment was found while ticagrelor showed a homogenous distribution with higher LR and lower HR rate compared to prasugrel.
- © 2012 by American Heart Association, Inc.