Purpose: to investigate vWF-dependent platelet adhesion of patients with premature myocardial infarction at shear rates below critical value (1200-1300s-1).
Methods: Using a microfluidic system, we measured platelet adhesion to a fibrinogen-coated optical surface at shear rates of 1200-1300 s-1 during 10 minutes. We assessed platelet-rich plasma of 8 male persons 40-52 years old, who had previous myocardial infarction at the age of 34-39. The control group comprised 6 healthy male volunteers 30-55 years old. We compared the intensity of scattered laser light measured in volts (V) at 10th minute. To study vWF-dependent platelet adhesion, we blocked GPIb receptor with monoclonal antibody to inhibit platelet interaction with vWF. To compare the intensity of vWF-dependent platelet adhesion with normally occurring adhesion to fibrinogen, we blocked GPIIb/IIIa receptor with monoclonal antibody.
Results: The inhibition of GPIb vWF-receptor decreased platelet adhesion to fibrinogen surface at shear rates of 1200-1300s-1 by 17.8±4.7% in healthy volunteers and by 92±2.8% in persons with premature myocardial infarction (p<0.05). Inhibition of GPIIb/IIIa receptor decreased platelet adhesion by 91.5±3.8% in healthy volunteers and by 97.3±3.2% in persons with premature myocardial infarction. Conclusion: Pathologic unfolding of vWF at shear rates below critical value may be involved in the development of premature myocardial infarction.