Prevalent platelet dysfunction in patients with aortic valve disease.

Area of Science:

• Cardiovascular Medicine
• Hematology
• Biomedical Engineering

Background:

• Heart valve disease, particularly aortic valve disease, leads to rough, calcified valve leaflets.
• This surface irregularity disrupts normal blood flow and is suspected to activate the hemostasis system.
• The precise mechanisms underlying this activation remain incompletely understood.

Purpose of the Study:

• To investigate platelet function in patients with heart valve disease undergoing aortic valve replacement (AVR).
• To compare platelet function in AVR candidates with patients undergoing coronary artery bypass graft (CABG) surgery.
• To explore the potential role of platelet dysfunction in the pathogenesis of microvascular complications in AVR.

Main Methods:

• Platelet function was assessed preoperatively in 660 CABG and 421 AVR candidates using the platelet function analyzer (PFA-100).
• PFA results were reported as closure time.
• Subgroups of 40 AVR and 50 CABG patients also had von Willebrand factor antigen and collagen-binding activity measured.

Main Results:

• Platelet dysfunction was significantly more prevalent in AVR candidates (83%) compared to CABG candidates (22%).
• Mean PFA closure time was markedly higher in AVR patients (231 ± 59 s) than in CABG patients (153 ± 60 s; p < 0.01).
• No significant differences were observed in mean platelet volume, platelet distribution width, or von Willebrand factor levels between the groups.

Conclusions:

• Disturbed blood flow and shear stress in aortic valve disease likely lead to platelet activation, degranulation, and microparticle shedding.
• These altered platelet characteristics may contribute to microvascular dysfunction and thrombotic events in patients with aortic valve disease.
• Platelet dysfunction is a key finding in AVR patients, suggesting a potential mechanism for associated complications.