[Diagnosis and treatment of venous thrombosis]

The subject of this guideline from the Institute of Family Medicine at the University of Zurich (IHAMZ) is the management of venous thrombosis. The review summarizes the current evidence and recommendations from international guidelines (1-6). The IHAMZ-guidelines focus on primary care, they also provide guidance on the coordination of general and specialist medical care as well as on the transition between outpatient and hospital care taking into account the special features of the Swiss healthcare system. The guideline is devided in two parts. Part 1 discusses the diagnosis and treatment of deep vein thrombosis (DVT). A validated algorithm is recommended for the diagnostic process, which begins with the assessment of the clinical probability. With the inclusion of the D-dimer test, the need for subsequent imaging diagnostics can be reduced. The differences between the evaluation of an initial and recurrent DVT are shown and the indications and scope of evidence-based environmental diagnostics (thrombophilia and tumor search) are presented. All patients with DVT should receive anticoagulation (AC) for 3-6 months, as there is a high risk of recurrence with AC  3 months. The duration of the subsequent secondary prophylaxis depends on the presumed risk of recurrence on the one hand and the risk of bleeding on the other. Part 2 is dedicated to special thrombosis situations such as shoulder-arm vein thrombosis (SAVT), cancer-associated thrombosis (CAT) and superficial vein thrombosis (SVT). The article on hormone- and pregnancy-associated DVT, developed together with the Department of Gynecology at the University Hospital of Zurich, discusses the importance of hormonal contraception and menopausal hormone replacement therapy (HRT) as a thrombogenic risk factor as well as special features in the diagnosis and treatment of thrombosis in pregnancy.