LAUSR

Venous aneurysms are extremely rare, with around 500 cases reported in the literature; there is often confusion as to optimal management and currently no established standard of care. Venous aneurysms can occur at any age, have an equal gender distribution and may arise in any vein, but are most commonly found in the popliteal vein. The exact pathophysiology of disease is unknown but histologically, venous aneurysms demonstrate fragmentation of the elastic lamellae with loss of smooth muscle cells, as well as increased expression of MMP-2, MMP-9 and MMP-13. Disease is classified as primary or secondary to trauma, arteriovenous malformation, fistula formation, or connective tissue disorder. A systematic review of the literature on deep venous aneurysms was published in 2018, with aneurysm categorisation according to location. Surgical repair was recommended in symptomatic patients or in patients with evidence of thromboembolism. There is no consensus on the management of asymptomatic patients. The low incidence of venous aneurysm makes it difficult to assess interventional outcomes, long-term management and the incidence of post thrombotic sequelae. There is currently no uniformity between different centres in their management, and multi-institutional collaboration should be encouraged. Evidence of thrombosis is an indication to consider intervention to reduce the risk of pulmonary embolism (PE) in individuals. The majority of deep vein thromboses (DVT) present in lower limb venous aneurysms, most commonly the popliteal vein. Saccular aneurysms are also considered to present a higher risk of DVT. Surprisingly, anticoagulation alone does not seem to reduce the risk of thromboembolic events (VTE), as venous aneurysms provide an environment for clot formation and propagation. There is at least a 60% chance of recurrent VTE following anticoagulation therapy. Anticoagulation does however have a role following surgical intervention, with individuals typically anti-coagulated for 3-6months post procedure. Abdominal venous aneurysms are often candidates for intervention. Aneurysms may affect any abdominal vein but are most frequently found in the portal vein or superior mesenteric vein. Abdominal aneurysms are at risk of complications including portal hypertension, rupture and fistulisation with subsequent gastrointestinal bleed. Intervention is indicated in individuals with low surgical risk, but a high risk of fatal complications. A role for surveillance of asymptomatic, “low risk” venous aneurysms has been proposed. This is controversial as there are no clear parameters (location, size and perceived VTE risk) that are associated with complications. The rationale for surveillance is that: a) Upper limb venous aneurysms are usually asymptomatic and not associated with VTE. Intervention is therefore rare. b) Head and neck venous aneurysms do not have a significant risk of rupture or VTE, and intervention is indicated only for cosmesis or symptoms of mass effect. c) Risk of DVT in superficial venous aneurysms is low, and intervention is most commonly indicated for symptomatic relief. d) Thoracic venous aneurysms may be associated with symptoms including chest pain and shortness of breath, but rupture and VTE are rare. Intervention for these aneurysms is associated with significant morbidity and mortality. e) Lower limb deep venous aneurysms may also be monitored if asymptomatic and small. However, there is no established association between aneurysm size and VTE risk which could provide a clear indication of when to intervene. Additionally, symptoms of pain and swelling associated with deep venous aneurysm may be related to post-thrombotic sequelae or valve dysfunction, which may not improve with surgical resection of the aneurysm. Truncal venous malformations may also present as a venous aneurysm, stenosis or dilatation. There are a wide variety of venous malformations, which can be