Optimizing of thienopyridine therapy by multiple electrode platelet aggregometry in clopidogrel low responders undergoing PCI

AIMS

One possible cause of stent thrombosis is an insufficient effect of clopidogrel. In a prospective study, we aimed to optimize the platelet inhibition of clopidogrel low responders (CLR) by multiple electrode platelet aggregometry (MEA)-guided therapy modifications and to evaluate specific major adverse cardiac and cerebrovascular events (MACCE).

METHODS AND RESULTS

ADP-induced platelet aggregation was measured by MEA in 1,005 consecutive patients after stent implantation and 600 mg clopidogrel loading dose. All patients received at least 100 mg aspirin/day. In 118 patients (11.7%), ADP values remained in the reference range generated in 150 controls and were defined as CLR. Significant independent predictors of CLR were acute coronary syndrome (ACS) (OR = 6.54), diabetes (OR = 2.07), use of diuretics (OR = 1.93) or proton pump inhibitors (OR = 1.64) and male gender (OR = 1.83). Ninety-nine CLR were switched to clopidogrel 150 mg/day, leading to an adequate response in 54/99. Subsequently, 44 patients were changed to ticlopidine 2 × 250 mg/day, resulting in an inhibition in 24/44. The remaining 20 patients received 2 × 100 mg cilostazol/day in addition to 75 mg clopidogrel/day. After its recent availability, 19/118 primary CLR were treated with 5-10 mg prasugrel/day. One patient was a prasugrel low responder. The total thienopyridine low response-rate was 2% in our population. The specific MACCE rate (death, non-fatal target vessel myocardial infarction, non-fatal stroke) of the CLR under optimized treatment (except prasugrel) was 2.0% at 30 days and 3.0% during a mean follow-up of 44 weeks.

CONCLUSION

Clopidogrel low response is present in 1/10 patients and more frequent in ACS-PCI. MEA-guided optimizing of thienopyridine therapy is feasible and results in a very low specific MACCE rate. Low response to all thienopyridines is rare.

Hydrophoretic high-throughput selection of platelets in physiological shear-stress range

A gentle, but fast means for low-stress, high-throughput platelet purification is of significant clinical and biotechnological utility. Current implementations to sort platelets, however, require an external physical field, specialized buffer, or the harsh separation condition of high shear stress that tends to cause platelet stimulation. Here we report the use of hydrophoretic size separation in a wider channel and its parallelization to augment its throughput capability, maintaining physiological shear-stress range. We demonstrate a parallelized device comprising 10 stacks of the wide-channel hydrophoresis device, yielding a throughput of 2.9 million cells s(-1) and a platelet purity of 76.8%. The use of the wide channel for hydrophoresis also facilitates clogging-free separation by sorting blood clots and plaques. The wide-channel hydrophoresis offers the potential for gentle, fast, clogging-free sorting of rare blood cells with extreme throughput capabilities.