It has long been recognized that nephrotic syndrome is associated with an increased risk for thromboembolic complications, including deep venous thrombosis, renal vein thrombosis, and pulmonary embolism. This risk varies with the nature of the underlying disease and seems to be greatest for membranous nephropathy. Other factors, including the level of serum albumin, previous thromboembolic episodes, and a genetically determined predisposition to thrombosis, may also be involved. Prevention of thromboembolic events with oral anticoagulants in nephrotic syndrome requires a careful case-by-case analysis of the risks for thromboembolic events balanced by the risks for anticoagulant induced bleeding. Markov-based decision analysis using literature-based assumptions regarding these risks has suggested that prophylactic anticoagulants may be indicated in certain circumstances. Such decisions need to take into account the nature of the underlying disease, the severity of the nephrotic syndrome (as assessed by serum albumin concentration), preexisting thrombophilic states, and the overall likelihood of serious bleeding events consequent to oral anticoagulation (as assessed by the international normalized ratio for prothrombin time). The optimal duration of prophylactic anticoagulation is unknown but very likely extends to the duration of the nephrotic state per se.
