Summary
Plasma and urine samples from 17 men who had suffered a myocardial infarction before
the age of 45 years were quantitatively and qualitatively analyzed for von Willebrand
factor antigen (vWF), and compared with samples obtained from controls. The levels
of vWF in plasma and its characteristic multimeric composition in the patient samples
were not different from those of the controls. However, when analyzed for lower molecular
weight components, plasma samples from some patients contained more degraded material
than those of the controls as indicated by the presence of an extra protein band of
vWF related material having a molecular weight of about 200 kDa. The levels in urine
of vWF and the molecular weight of the fragments excreted did not differ between patients
and controls. A relative increase in excretion of lower molecular fragments was, however,
observed in the patient group. In a second group of 97 consecutive post-infarction
patients under the age of 45 years the extra 200 kDa vWF band was found in 46% of
the patients, whereas it was not detected in control plasmas. Taken together these
findings suggest that degraded forms of vWF occur in normal plasma and that a more
extensive degradation may occur in patients with coronary atherosclerosis, which could
account for the relative increase in the excretion of lower molecular weight fragments
observed in these patients.
