Hydrasys 2 system

Blood samples were collected at baseline, 4 min after the start of exercise, during peak exercise and at 5, 10 and 30 min after exercise (figure 1) using peripheral venous access with a 3 mm needle in the arm or hand. From these blood samples, the HMW-multimer ratio of vWF (HMWMs) and CT-ADP were measured. HMWMs was defined as the relative amount of HMW-multimers (larger than 15-mers) in the sample compared with normal pooled plasma (NPP; standard human plasma) as previously described.29 (link) This ratio of HMW-multimers to normal pooled plasma equals 1 without any abnormalities and becomes <1 when the HMW-multimer ratio is reduced. The CT-ADP was measured using the Platelet Function Analyzer (PFA)−100 (Siemens Medical Solutions Diagnostics, Netherlands), vWF multimers were analysed on a Hydrasys 2 system using ‘Hydragel von Willebrand Multimers’ and ‘von Willebrand Multimers Visualisation’ kits (all from SEBIA, Belgium). Analysis of CT-ADP with the point-of-care assay PFA-100 is used as a surrogate marker of vWF loss. Higher values correspond to a longer closure time and more loss of vWF. All assessments were done in our tertiary hospital laboratory with laboratory personnel blinded to clinical data.