Immature Platelet Fraction and Clinical Outcomes in Patients Undergoing Transcatheter Aortic Valve Implantation

Introduction: Immature platelets or reticulated platelets are newly released thrombocytes. They can be identified by their large size and high RNA cytoplasm concentration. Immature platelet fraction (IPF) represents the percentage of immature circulative platelets relative to the total number of platelets. The role of IPF in patients undergoing transcatheter aortic valve implantation (TAVI) is unknown. The aim of the current trial was to assess the levels of IPF in patients undergoing TAVI and correlation with clinical outcomes. Material and Methods: Immature platelet fraction levels were measured 3 times in all patients (preprocedure, 1-2 days post-procedure and 1-month post-procedure). Immature platelet fraction measurement was carried out using an autoanalyzer (Sysmex XE-2100). Patients were followed for 12 months. Primary outcomes were defined as complications during hospitalizations, rehospitalization, and mortality. Results: Fifty-one patients were included in the study. Mean age was 79.8 (+/- 9.6), and 28 (55%) were women. Twenty-one patients (41%) had complications: Of them, 6 of 21 (29%) occurred during hospitalizations (2-vascular complications; 2-sepsis, 2-implantation of a pacemaker), 9 of 21 (43%) patients were rehospitalized after the index admission, and 6 patients died during the follow-up period. Multivariate Cox regression analysis found that IPF < 7% in at least one of the 3 tests was associated with worse outcomes (hazard ratio 3.42; 95% CI 1.11-10.5, P = .032). Conclusion: Immature platelet fraction >7% in patients undergoing TAVI is associated with worse outcomes. Further studies are needed to better understand this phenomenon.