Effect of transcatheter (via femoral artery) aortic valve implantation on the platelet count and its consequences

Abstract

Decrease in blood platelet count has been described after percutaneous coronary intervention and surgical valve replacement, although no study has been performed in the setting of transcatheter aortic valve implantation (TAVI). The aim of this study was to address the incidence, mechanism, and impact of blood platelet count decrease after TAVI. One hundred forty-four consecutive patients (mean age 84 ± 7 years, 64 men) with severe symptomatic aortic stenosis who underwent TAVI from December 2007 to July 2011 were enrolled. Blood platelet count was recorded before and after aortic valve implantation. Decrease in blood platelet count was compared with in-hospital major adverse cardiovascular events (death, stroke, and major or life-threatening bleeding). Blood platelet count decreases occurred in all but 1 patient. The percentage of platelet count decrease averaged 34 ± 15% and was 24% greater than blood protein decrease. Decrease in platelet count was associated with a higher rate of prosthesis migration, longer x-ray and procedural times, and larger contrast amounts (230 ± 128 ml for the third tertile vs 170 ± 77 ml for the second and first tertiles, p = 0.0006), but no association was observed with regard to changes in bilirubin. In-hospital major adverse cardiovascular events (n = 50 [35%]) were observed more frequently in patients with severe platelet count decreases (21% for the first tertile, 35% for the second tertile, and 48% for the third tertile, p = 0.02). Finally, the percentage of blood platelet count decrease was the only predictor of in-hospital major adverse cardiovascular events (odds ratio 1.67, 95% confidence interval 1.05 to 2.67, p = 0.03). In conclusion, a decrease in platelet count is a common phenomenon after TAVI, and its severity is associated with poor outcomes.