Light transmittance aggregometry (LTA) has been extensively used in monitoring clopidogrel therapy. However, the availability of simple and rapid point-of-care platelet function assays is of great clinical importance. Thus, the manufacturer of the Platelet Function Analyzer (PFA)-100 System has recently produced the INNOVANCE PFA P2Y test cartridge. We assessed the ability of this new test to reliably detect clopidogrel resistance. We enrolled 90 consecutive patients with coronary artery disease receiving chronic clopidogrel maintenance therapy in combination with aspirin. Twenty healthy volunteers served as controls. Clopidogrel resistance was simultaneously analysed by the INNOVANCE PFA P2Y test cartridge, ADP-induced LTA, the flow-cytometric vasodilator-stimulated phosphoprotein (VASP)-phosphorylation assay and the multiple electrode aggregometry (Multiplate). Agreement among the four platelet function methods by two was assessed using Cohen's kappa coefficient. According to the cut-off points for clopidogrel resistance proposed by the literature, agreement was fair between INNOVANCE PFA-100 P2Y and LTA (74.4%) and Multiplate (75.6%), while poor agreement was noticed in VASP assay (63.3%). Based on cut-off points indicating a higher thrombotic risk, agreement between the PFA-100 System and the other three methods did not significantly differ compared to the previous cut-offs (72.2%, 71.1% and 55.1%, respectively). The INNOVANCE PFA-100 P2Y test seems to be comparable to other established platelet function assays in detecting clopidogrel resistance. However, the modest agreement among platelet function methods makes the performance of platelet function testing crucial with more than one technique in order to reliably identify poor responders to clopidogrel treatment.
1 November 2007 in Applied and Environmental Microbiology
Retrospective molecular and phenotypic characterization of a vaccine-derived poliovirus (VDPV) type 1 isolate (7/b/97) isolated from sewage in Athens, Greece, in 1997 is reported. VP1 sequencing of this isolate revealed 1.87% divergence from the VP1 region of reference strain Sabin 1, while further genomic characterization of isolate 7/b/97 revealed a recombination event in the nonstructural part of the genome between a vaccine strain and a nonvaccine strain probably belonging to Enterovirus species C. Amino acid substitutions commonly found in previous studies were identified in the capsid coding region of the isolate, while most of the attenuation and temperature sensitivity determinants were reverted. The ultimate source of isolate 7/b/97 is unknown. The recovery of such a highly divergent derivative of a vaccine strain emphasizes the need for urgent implementation of environmental surveillance as a supportive procedure in the polio surveillance system even in countries with high rates of OPV coverage in order to prevent cases or even outbreaks of poliomyelitis that otherwise would be inevitable.