Decline in platelet count in patients treated by percutaneous coronary intervention: definition, incidence, prognostic importance, and predictive factors.

AIMS We investigated the incidence, predictors, and prognostic impact of a decline in platelet count (DPC) in patients treated by percutaneous coronary intervention (PCI). METHODS AND RESULTS A total of 10 146 consecutive patients treated by PCI from 2003 to 2006 were included. According to the magnitude of the DPC, the population was divided into four groups: no DPC (<10%), minor DPC (10-24%), moderate DPC (25-49%), and severe DPC (>or=50%). The primary haemorrhagic endpoint was a composite of post-procedure surgical repair major bleeding. The primary ischaemic endpoint was 30-day all-cause mortality-non-fatal myocardial infarction. Among the total population, 36% had a DPC <10%, 47.7% had a DPC of 10-24%, 14% had a DPC of 25-49%, and 2.3% had a DPC >or=50%. On multivariate analysis, moderate and severe DPC were independent predictive factors of the ischaemic outcome. Two procedural practices were identified that, if modified, might reduce the incidence of acquired thrombocytopaenia. Both the intraprocedural use of heparin (as opposed to bivalirudin) and of low molecular weight contrast material were independently associated with severe acquired thrombocytopaenia. CONCLUSION Moderate and severe DPC are independent predictors of adverse bleeding and ischaemic outcomes in PCI. Adoption of intraprocedural anticoagulant other than heparin and avoidance of a low molecular weight contrast agent could potentially decrease the occurrence of severe acquired thrombocytopaenia.