1Universitäts-Herzzentrum Freiburg / Bad Krozingen Klinik für Kardiologie und Angiologie Bad Krozingen, Deutschland; 2Inselspital - Universitätsspital Bern Universitätsklinik für Kardiologie Bern, Schweiz; 3Klinikum Würzburg Mitte gGmbH Kardiologie & Internistische Intensivmedizin Würzburg, Deutschland
Background:
Immature platelets (IP) or also called reticulated platelets are newly developed platelets that have just been secreted from the bone marrow into the bloodstream. They have a larger volume, increased RNA content and are more reactive than normal platelets. Studies have shown that higher levels of IPs are associated with major adverse cardiovascular events in patients with acute myocardial infarction. Additionally, patients with atrial fibrillation (AF) have increased levels of IP in comparison to sinus rhythm (SR). This study analyzed if increased levels of IP in patients with AF are associated with major adverse cardiovascular events.
Methods:
PRISCA-AF is a prospective, monocentric study for the evaluation of immature blood cells for clinical risk stratification in patients with AF. The study enrolled patients admitted to our heart center due to AF of any type (acute onset, known paroxysmal or persistent). Therefore, patient could be in AF or SR at time of admission. Blood samples were taken immediately at hospitalization and IPs were measured automatically with a cytometer (Sysmex XN-1000). After 1 year follow up was performed with a written or phone call questionnaire.
Results:
The present analysis included 1636 patients. Complete follow was available in 1374 patients (84 %) of which 487 were female (35.4%) and median age was 70 years [61-77 years]. Electric cardioversion was performed in 570 (41.5%) and PVI in 332 (24.2%) of patients. Levels of IPs were significant higher (p = 0.011) in patients with AF (9.5 x 10³/µl [6.8-13.3]) than in SR (9.0 x 10³/µl [6.4-12.3]). At the time of study inclusion, 1242 (90.4%) of the patients were on oral anticoagulation, and 1338 (97.4%) at one year follow-up. Only 510 (37.1%) patients had ongoing AF and of these only 216 (42.4%) were symptomatic at 12-month follow-up. the incidence of thrombotic (13 (0.9%)) or bleeding events (BARC ≥ 3; 14 (1.0%)) within 1 year was low. However, 186 (13.5%) of patients were re-hospitalized within one year because of a new onset of symptomatic AF. Logistic regression analyses showed a significant association of levels of IP and risk of readmission (p = 0.043; 95% CI: 1.001 – 1.050; OR: 1.025) but not with thrombotic (p = 0.211) and bleeding (p = 0.200) events.
Conclusion:
Levels of IP are higher in patients with AF as compared to patients in SR. Higher levels of IP were associated with clinical events but not with thrombotic and bleeding events