Thrombocytopenia at baseline is a predictor of inhospital mortality in patients undergoing percutaneous coronary intervention.

Background: Thrombocytopenia (TP) is a common baseline abnormality in patients undergoing percutaneous coronary intervention (PCI). Whether TP has any influence on the outcome of PCI patients is unknown. Our aim was to determine if TP at baseline impacts on inhospital mortality in patients undergoing PCI at our institution.

Methods: From April 2000 until October 2005, 11,021 PCI procedures were performed at the University Health Network in Toronto, Canada. Baseline platelet count was recorded in 10,821 (98.2%) cases. Patients with platelets <150 x 10(9)/L were assigned to the TP group (n = 639), and those with > or =150 x 10(9)/L to the normal platelet group (n = 10,182). Clinical, angiographic, procedural, and inhospital outcome data were collected prospectively. Multivariable analysis was performed using logistic regression.

Results: In-hospital death rate was higher in the TP group (1.9% vs 0.6%, P < .001) due to an increased mortality in TP patients undergoing urgent (3.55% vs 1.15%, P < .001) but not elective (0% vs 0.04%, P = 1.0) PCI. Major bleeding (1.7% vs 0.8%, P < .05) and gastrointestinal bleeding (1.1% vs 0.5%, P < .05) complications were greater in the TP group. Multivariate analysis demonstrated that baseline TP was an independent predictor of inhospital mortality (odds ratio 2.07 [1.1-4.1], P = .035).

Conclusions: Baseline TP is an independent predictor of inhospital mortality in patients undergoing PCI for urgent indications. Thrombocytopenia should be considered an important addition to PCI risk prediction models to improve their precision and clinical applicability.