Venous thromboembolism and prothrombotic parameters in Klippel-Trenaunay syndrome.

In Klippel-Trenaunay syndrome (KTS), a congenital combined vascular (capillary, venous and lymphatic) malformation with localised disturbed growth, venous thromboembolisms (VTEs) are frequently reported in small cohorts. We quantified the frequency of VTE by screening a large KTS-patient cohort with duplex compression ultrasonography. Additionally, we performed a case-control study to evaluate whether coagulation alterations were related to VTE and magnitude of vascular malformations as quantified by magnetic resonance imaging (MRI). Twenty-nine (39%) of 75 patients had signs of current or previous VTE, including superficial venous thrombosis, six (8%) of whom had a deep venous thrombosis or a pulmonary embolism. Compared with 105 controls, 54 adult patients (both: median age 33 years) had higher plasma levels of D-dimer, medians 266 (IQR 195-366) versus 457 (IQR 270-3840) mg÷l (p