Renal vein thrombosisNephrology discussion

Dr. CoetserProf. Van Rensburg and dr. Rossouw

Our case

Epidemiology

RVT is seen in 10-50% of patients with nephrotic syndrome◦ RVT seen in 20-60% of membranous nephropathy◦ Also associated with:

Minimal change glomerulonephritis Membranoproliferative glomerulonephritis Focal segmental glomerulosclerosis

Other associations:◦ Renal malignancy◦ External compression from e.g. lymphnodes, aneurysms◦ Oral contraceptive use and pregnancy◦ Hypovolaemia secondary to severe dehydration◦ Inherited procoagulant disorders

Antiphospholipid syndrome, factor V Leiden◦ Trauma, including kidney bx

Pathogenesis of RVT in the nephrotic syndrome

Hypercoagulability◦ Decreased levels of antithrombin III and plasminogen◦ Hyperfibrinogenaemia◦ Increased platelet activation◦ Fibrinogen moieties circulating◦ Inhibition of plasminogen activation

Tendency to thrombose in renal vein◦ Loss of fluid over glomerulus causes increased

haematocrit in post-glomerular venous circulation

Clinical presentation

Complete venous obstruction causes swelling of the kidney, compromising arterial blood flow and leading to a haemorrhagic infarct

Thrombosis can be unilateral or bilateral, can extend into the inferior vena cava

Acute RVT◦ Asymptomatic◦ Flank pain◦ Microscopic or macroscopic haematuria◦ Nausea and vomiting

Chronic RVT◦ Asymptomatic, usually presents with pulmonary

embolism

Diagnosis

Gold standard is selective renal venographyOther options:

◦ CT abdomen with contrast◦ MRI◦ Doppler ultrasonography

Blood tests:◦ Rise in urea and creatinine if bilateral◦ Rise in LDH

Inferior cavography

Thrombus extending from the left renal vein into the inferior vena cava

Contrast CT abdomen

A thrombus extends from the left renal vein to the inferior vena cava. Note that the left renal vein runs retroaortic.

MRI

Left renal vein thrombosis in a patient with renal cell carcinoma.

Screening

Not recommended to routinely screen for RVT in all patients with nephrotic syndrome:◦ No proven benefit in diagnosing occult disease◦ A patient with a negative test can develop RVT at a later

stage, meaning that sequential tests need to be done

Not recommended to look for RVT in patients presenting with embolic phenomenon, e.g. pulmonary embolism◦ Difficult to prove that embolism originated in renal vein◦ In situ pulmonary thrombosis could occur in nephrotic

syndrome◦ Both nephrotic patients presenting with

thromboembolism and those with RVT need anticoagulation therapy

Prophylaxis for RVT

Not routinely recommended in nephrotic syndrome

Authors of UpToDate recommend prophylaxis in:◦ Severe proteinuria >10g/day◦ Albumin <20g/L◦ Another risk factor for venous thromboembolism, e.g.

orthopaedic or gynaecological surgery, immobilization etc.

Treatment of RVT

AnticoagulationCan be used alone if:

◦ Normal renal function◦ No flank pain◦ No other evidence of thromboembolism

Unfractionated or low molecular weight heparin, followed by warfarin for minimum of 6-12 months

Recommended to continue as long is nephrotic syndrome persists

Treatment of RVT

FibrinolysisSystemic fibrinolysis is not recommended due to

the complication of haemorrhage and increased mortality (14-49% mortality)

Local fibrinolysis very effective in reports:◦ 7 patients received local thrombolysis for 22h following

catheter thrombectomy. All had restoration of renal venous flow, improvement in creatinine and no recurrence of RVT in the 2 year follow-up

◦ No haemorrhagic complication reportedNo particular agent proven to be superior at

present

Treatment of RVT

Indications for fibrinolysisAcute bilateral RVT and acute renal failureExtension of thrombus into inferior vena cavaAcute renal failureMassic thrombus with high risk of systemic

embolizationPulmonary embolism presentSevere flank pain

Treatment of RVT

Contraindications to fibrinolysis History of haemorrhagic stroke Active intracranial neoplasm Recent (< 2 months) intracranial surgery or trauma ABSOLUTE

Active or recent internal bleeding in prior 6 months

Bleeding diathesis Uncontrolled severe hypertension (systolic

BP >200 mmHg or diastolic BP >110 mmHg) Nonhaemorrhagic stroke within prior 2 months RELATIVE

Surgery within the previous 10 days Thrombocytopenia (<100,000 platelets per mm3)

Post-partum thrombolysis haemorrhagic risk is highest in first 8h following delivery. No clear guidelines exist as only a few case

reports have been described.

Treatment of RVT

Catheter thrombectomyTechnique described in 7 patients:

◦ Treated initially with heparin to keep PTT 2-2,5x normal◦ Percutaneous access via right femoral vein◦ Catheter guided into thrombosed renal vein◦ Direct renal venogram obtained◦ Mechanical thrombectomy done with AngioJet or Helix

Clot Buster◦ Residual thrombosis treated with local fibrinolysis

(alteplase or urokinase)◦ Any remaining stenosis treated with balloon venoplasty◦ Heparin infusion reinitiated, followed by chronic

anticoagulation with warfarin

Treatment of RVT

SurgerySurgical thrombectomy only indicated in acute

bilateral RVT with acute renal failure which can not be treated with local fibrinolysis or catheter thrombectomy

Bibliography

Fauci, AS, Braunwald, E. Harrison’s principles of internal medicine, 17th edition, 2008. 1815.

Hyun, S et al. Catheter-directed thrombectomy and thrombolysis for acute renal vein thrombosis. Journal of vascular interventional radiology, 2006. 17:815-822

Radhakrishnan, J. Renal vein thrombosis and hypercoagulable state in nephrotic syndrome. UpToDate v17.3

Saddiqi, A et al. Renal vein thrombosis. http://emedicine.medscape.com/article/382686-overview

Tapson, VF. Fibrinolytic (thrombolytic) therapy in pulmonary embolism and deep vein thrombosis. UpToDate v17.3.

Waldemar, E et al. Clinical characteristics and long-term follow-up of patients with renal vein thrombosis. American journal of kidney diseases, 2008. 51:224-232.