Determination of ADAMTS-13 Activity in 13 Patients with Ischemic Stroke

FARÍAS, CRISTINA; KEMPFER, ANA CATALINA; SANCHEZ LUCEROS, ANALÍA; AMARAL, MARIA MARTA; VERA, EZEQUIEL; LAZZARI, MARÍA

Sydney, Australia

Congreso; XXth International Society on Thrombosis and Haemostasis Congress; 2005

ntroduction:  von Willebrand (VWF) a multimeric glycoprotein is involved in platelet adhesion to the subendothelium of damaged blood vessels. ADAMTS-13 cleaves plasma VWF regulating its activity. Mutations in ADAMTS-13 produce severe deficiency of this enzyme in patients with Thrombotic Thrombocytopenic Purpura (TTP). Deficiency of ADAMTS-13 could also contribute to thrombosis in patients without TTP. In a previous work, a partial ADAMTS-13 deficiency was detected in 3/70 patients with ischemic stroke (IS). The patient with lowest ADAMTS-13 activity of 17% suffered from idiopathic, recurrent IS (Bohm, BCF 2003). The low levels of ADAMTS-13 in this patient suggested that the assessment of ADAMTS-13 activity would offer important information for the prognosis of this pathology. Patients and methods:  we analyzed ADAMTS-13 activity in 11 patients with IS and 2 patients with recurrent IS between 28 and 53 years of age and in 18 healthy controls. All patients were tested in clinical remission and in the absence of apparent, acute inflammation and pregnancy. We measured ADAMTS-13 activity according to our published method (Kempfer, BCF 2003), on purified human VWF. Residual collagen binding activity of degraded purified VWF was determined according to a previously technique (Gerritsen, TH 1999). Results:  ADAMTS-13 levels were: 105 ± 25 U/dL (mean ± SD) in 11 patients and 65 U/dL and 117 U/dL in the two patients with recurrent IS. These results did not differ significantly compared to controls (95 ± 37 U/dL). Conclusion:  we did not find deficiency of ADAMTS-13 in patients with IS. Our results from two patients with recurrent IS do not suggest that ADAMTS-13 deficiency would offer information for the prognosis of this pathology.