From the Guidelines
Nephrotic syndrome increases the risk of deep vein thrombosis (DVT) primarily due to urinary loss of anticoagulant proteins and increased production of procoagulant factors, with the risk being particularly high when serum albumin falls below 2.9 g/dL, as noted in the 2023 study 1. The significant proteinuria in nephrotic syndrome leads to urinary loss of antithrombin III, protein C, and protein S, which are important anticoagulant proteins. Simultaneously, the liver increases production of procoagulant factors like fibrinogen, factor V, and factor VIII in response to hypoalbuminemia. Some key points to consider in the management of DVT in nephrotic syndrome include:
- The use of diuretics for edema management can worsen hemoconcentration, while immobility from severe edema reduces venous return.
- Hyperlipidemia, another feature of nephrotic syndrome, promotes atherosclerosis and endothelial dysfunction.
- Membranous nephropathy carries the highest risk among nephrotic syndromes, as highlighted in the 2023 study 1.
- Prophylactic anticoagulation may be considered in high-risk patients, especially those with albumin levels below 2.9 g/dL or additional risk factors for thrombosis, as recommended in the 2021 guideline 1. Key considerations for prophylactic anticoagulation include:
- Serum albumin level, with a threshold of 2.9 g/dL, as noted in the 2023 study 1.
- Proteinuria level, with a threshold of >10 g/d, as recommended in the 2021 guideline 1.
- Body mass index, with a threshold of >35 kg/m², as recommended in the 2021 guideline 1.
- Presence of other risk factors, such as heart failure, recent orthopedic or abdominal surgery, or prolonged immobilization, as recommended in the 2021 guideline 1.
From the Research
Causes of Deep Vein Thrombosis (DVT) in Nephrotic Syndrome
The causes of DVT in nephrotic syndrome can be attributed to several factors, including:
- Hypercoagulation disorders due to the imbalance of procoagulant and anticoagulant mechanisms 2
- Urinary loss of antithrombotic factors, such as anticoagulants, due to the dysfunction of the glomerular filter selective permeability 2, 3
- Increased production of prothrombotic factors by the liver 2, 4
- Fibrinolysis depression 2
- Platelet activation 2
- Endothelial microparticles with high prothrombogenic activity 2
Pathophysiology of Thromboembolism in Nephrotic Syndrome
The pathophysiology of thromboembolism in nephrotic syndrome involves:
- Disturbances in the body's balance of thrombotic and antithrombotic abilities 5
- Severity of proteinuria and degree of hypoalbuminaemia as predictors of risk 5
- Hypercoagulability caused by acquired nephrotic syndrome 3
- Reduction in circulating antithrombin III and free protein S levels 3
Risk Factors for Thromboembolism in Nephrotic Syndrome
The risk factors for thromboembolism in nephrotic syndrome include: