Prevention and management of type II endoleaks after endovascular aneurysm repair

Endovascular aneurysm repair (EVAR) has emerged as a pivotal technique in managing abdominal aortic aneurysms. As with any medical intervention, EVAR poses inherent risks of complications. Among various post-EVAR complications, a major one is endoleaks, characterised by periprosthetic leakage. Various types of endoleaks exist, with type II being the most commonly observed, resulting from blood reperfusion into the aneurysm sac through the lumbar and/or inferior mesenteric artery (IMA), median sacral, or accessory renal arteries. Due to the low-pressure nature of type II endoleaks, consequences may range from patients being asymptomatic to experiencing life-threatening situations. The risk of aneurysm rupture in cases of isolated type II endoleaks is relatively low, estimated at 0.5% to 2.4%. Therefore, routine observation is generally recommended, and intervention is reserved for situations where there is a persistent increase in the aneurysm sac diameter by more than 5 mm over 6 months or the occurrence of other complications, such as rupture of the aneurysm sac. If detected during the procedure, type II endoleaks often resolve spontaneously, making immediate treatment unnecessary. Factors contributing to the persistence of such leaks include an active IMA, a high number and diameter of active lumbar arteries, and ongoing anticoagulant treatment. The long-term effects of type II endoleaks vary, with the aneurysm sac shrinking in 25% of patients, remaining unchanged in the majority of patients (50-70%), and enlarging in a few patients (12%). Treatment options, if needed, encompass diverse methods such as embolisation of the IMA or lumbar arteries using coils, occluders, or tissue adhesives, injection of polymers directly into the aneurysmal sac, or laparoscopic clipping of the IMA and lumbar arteries. However, the effi cacy of these methods varies, with the aneurysm continuing to grow in 60% of patients, often necessitating repeat procedures or even graft removal and traditional surgery. Despite extensive research on type II endoleaks, therapeutic considerations remain unresolved. Moreover, the importance of intervention, optimal timing of procedures, most effective diagnostic methods, and treatment modalities for type II endoleaks remain controversial.