However, using currently available endografts, the incidence of type III endoleaks can be reduced to 1%, keeping in mind that the follow-up period with these types of endografts is shorter. The incidence ranged from 8% to 12%, probably because of the small overlap recommended for early multicomponent stents, as well as a slow-to-emerge understanding of the importance of affixing the fabric onto the stent. There was a relatively high incidence of early and late type III endoleaks in first- and second-generation endografts (mainly Stentor or Vanguard devices).
#TYPE 3 ENDOLEAK TRIAL#
The incidence of type III endoleak, as described in randomized controlled trials including the EVAR 1 trial 1 and the OVER trial 4 or in prospective registries like the EUROSTAR registry, 5 ranges from 3% to 4.5% and includes different types of endograft implants. 9,10 In fact, the modular design of grafts emerged, in part, to accommodate this intercomponent movement, and early practitioners observed that larger overlap allowed for accommodation of the device within a changing aortic sac without placing undue tension on the proximal and distal seal. The resulting endograft displacement is more prevalent with larger aneurysms and is associated with an increased incidence of type IIIa and type I endoleaks. 9 Disconnection is usually related to insufficient overlap among the stent graft components, but it has been hypothesized that late types can also occur because of conformational changes in the aneurysm sac, endograft migration, or dilatation of aortic and iliac attachment sites. 9 Most are asymptomatic, but approximately 10% of patients will present with clinical symptoms of a rupture. Conversely, late type III endoleaks can develop months to years later, with a median time interval of 5.6 years (range, 1–13.2 years) between the index procedure and diagnosis and treatment. 8 It is likely that as the durability of EVAR improves, a further very late fabric defect based on biologic degeneration may occur, similar to older open prosthetic grafts.Įarly type III endoleaks are visualized during completion angiography in the operating theater. Another potential cause of intraoperative-related fabric defects might be excessive pressure during ballooning.
The underlying mechanism of the fabric defects is still being debated and may include processes occurring during the initial procedure where the fabric is damaged by the tip of a stent displaced by severe angulation of the neck or by friction through heavily calcified, tortuous iliac arteries. Type IIIb includes disruption of the fabric of the endograft, such as fabric tears and stent fractures, and is further subdivided into holes > 2 mm or < 2 mm. Type IIIa endoleak is described as a disconnection between the main body and the contralateral limb but can also be due to disconnection of the iliac limb from the ipsilateral distal extension or of a proximal cuff from the endograft main body.
7 Type III endoleak includes two subtypes. 6 The most modern definition of type III endoleak is found in the reporting standards, which describe it as leakage between endograft components or fabric disruption.
1Įndoleak is defined as a persistent arterial perfusion of the aneurysm sac after endovascular treatment and was categorized in four types by White et al. 1-5 However, EVAR is also associated with higher reintervention rates compared with open repair, and endoleaks are the most common indication. It is associated with lower 30-day mortality and morbidity rates, as well as faster discharge. Endovascular aneurysm repair (EVAR) has gained wide acceptance as the preferred method of treatment for infrarenal abdominal aneurysms.
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