Prevalent platelet dysfunction in patients with aortic valve disease.
OBJECTIVE
In patients with heart valve disease, the valve leaflets display a gapped, rough endothelial lining often covered with calcified areas. As a consequence, blood flow is disturbed and a stimulation of components of the hemostasis system is assumed. The possible mechanisms of this process are, however, unclear at present.


METHODS
Platelet function was studied in 660 patients considered for isolated coronary artery bypass graft (CABG) surgery, and in 421 patients considered for single aortic valve replacement (AVR). Platelet function was monitored preoperatively using the platelet function analyzer device (PFA-100). The test results were reported as closure time of the membrane hole at the end of a capillary tube. The von Willebrand factor antigen, and its collagen-binding activity, were also determined among subgroups of 40 AVR and 50 CABG candidates.


RESULTS
Platelet dysfunction was displayed by only 22% of CAD patients, but by 83% of AVR candidates. The mean PFA closure time in AVR patients was considerably higher than in CAD patients (231 +/- 59 s versus 153 +/- 60 s, respectively; p < 0.01). The mean platelet volume, platelet distribution width and von Willebrand factor collagen binding and antigen levels did not differ between the patient groups.


CONCLUSIONS
It is assumed that, due to disturbed flow and shear exposition, following an initial activation, the platelets are partially degranulated, shed microparticles, and might become involved in the pathogenesis of microvascular dysfunction and thrombotic events in patients with aortic valve disease.
Prohaska
Wolfgang
W
Institute for Laboratory and Transfusion Medicine, Heart and Diabetes Center North Rhine Westfalia, University Hospital of the Ruhr, University Bochum, Bad Oeynhausen, Germany. wprohaska@hdz-nrw.de
Zittermann
Armin
A
Lüth
Jan U
JU
Inoue
Kazuo
K
Köster-Eiserfunke
Wilhelm
W
Baller
Detlev
D
Körfer
Reiner
R
Kleesiek
Knut
K
D000368:Aged; D000941:Antigens / Q000097:blood; D001024:Aortic Valve Stenosis / Q000097:blood* / Q000601:surgery*; D001791:Blood Platelet Disorders / Q000097:blood*; D015331:Cohort Studies; D001026:Coronary Artery Bypass; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000502:physiology; D010979:Platelet Function Tests; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D012189:Retrospective Studies; D014842:von Willebrand Diseases / Q000097:blood / Q000175:diagnosis; D014841:von Willebrand Factor / Q000276:immunology
D000941:Antigens; D010980:Platelet Membrane Glycoproteins; C029417:Von Willebrand antigen; D014841:von Willebrand Factor; C028254:von Willebrand factor receptor