**6.1 The heparins**

Despite some reports of successful prophylaxis with UFH and LMWHs a metaanalysis and systematic review of their use [117] found no significant reduction in risk of SOS. Safety also appeared to be an issue when used in patients with gastrointestinal varices or thrombocytopenia or renal dysfunction, especially when they were combined with lipo-prostaglandin E1 or UDCA. Hence heparin is no longer recommended for SOS prophylaxis [20].
