Natural History of Isolated Calf Vein Thrombosis - A Prospective Cohort Under Ultrasound Surveillance

The treatment of ICVT is still controversial as conflicting international guideline strategies show. Evidence suggests that propagation rates of ICVT without risk factors are low. Unless ICVT propagates to proximal veins anticoagulation can safely been withheld, thereby avoiding a bleeding risk for the patient. However, the impact of different risk factors on propagation rates is not well understood. This gap in knowledge can only be filled by a natural history study of ICVT without anticoagulation. Since patients are safe as long as no propagation occurs close ultrasound surveillance is an adequate safety umbrella for the natural history study period. In addition, it provides an objective outcome measure to define the impact of risk factors.