MID-TERM DURABILITY OF A SELECTED TREATMENT ALGORITHM FOR PROXIMAL ATTACHMENT SITE FAILURE AFTER EVAR

MID-TERM DURABILITY OF A SELECTED TREATMENT ALGORITHM FOR PROXIMAL ATTACHMENT SITE FAILURE AFTER EVAR
Background : Loss of proximal fixation by caudal device migration or type I endoleak has been associated with aneurysm (AAA) rupture and endograft explantation after EVAR. We present a mid-term audit of selected secondary interventions to re-establish proximal fixation, ameliorate type I leaks and preserve endograft function.
Methods : Forty patients (37 men/ 3 women, average age 77+7 yrs) were treated since 2001 for proximal fixation failure due to caudal device migration with remaining attachment lengths < 10 mm (n=12), type I endoleak (n=9) or both (n=19) at an average of 38 + 24 mo following EVAR. AAA size at secondary intervention was 6.6 + 1.7 cm with 17 cases experiencing sac expansion > 5 mm from initial post-op EVAR measurements and nearly all cases were associated with disadvantaged infrarenal neck anatomy (short, conical, wide, angulated). Specific secondary treatments were selected using an algorithm as follows : caudal migration less than 20 mm below the renals with aortic diameters < 25mm was treated with single available cuffs (Medtronic AneuRx preferred), longer (>20mm) lengths of attachment loss or wide necks (>25mm) required extended cuffs or aorto-uni-iliac (AUI) converters (with cross femoral bypass and contralateral iliac occluder) available through registry participation (Medtronic Talent, Cook Zenith Renu). Residual type I leaks required pararenal Palmaz stents (for Zenith devices) or open neck plication through limited abdominal exposures. CT-based follow-up after secondary interventions averaged 18 + 11 mo and ranged to 46 mo.
Results : Secondary procedures included 24 proximal cuffs, 5 extended cuffs, 8 AUI devices, 1 Palmaz stent, 1 aortobiiliac ‘endograft re-lining’, and 1 open neck plication. Adjunctive procedures (iliac extenders or renal stents) were done in 25 of the 40 cases. Six tertiary procedures (4 open plications, 1 stent, 1 AUI) were done within 48 hrs for residual type I leaks after secondary interventions. Device-specific failure modes included progressive caudal migration of AneuRx devices (n=26), type I neck leaks and partial device malapposition developing at early intervals (17+8 mo) after Gore Excluder (n=6), and late proximal fixation loss (72+17 mo) by neck dilatation / elongation after Guidant/EVT Ancure (n=4). During follow-up no recurrent type I leaks, ruptures, device explants or AAA-related deaths (3 non-AAA related) occurred. A single patient has experienced recurrent proximal migration > 5 mm (Talent cuff, 15 mm). AAA sac behavior included regression (>5mm) in 14 patients, 23 with unchanged diameters and 3 experiencing growth (due to type II leak). Type II leaks were present in 19 (48%) patients and 14 cases (74%) required embolization procedures for sac growth suggesting a link between fixation site destabilization and persistent branch leaks causing (partial) sac pressurization.
Conclusion : Favorable treatment of proximal fixation loss after EVAR can be achieved by selected use of available cuffs for short length migration in non-dilated necks but optimal therapy of long length migration requires aorto-uni-iliac conversion. Open neck plication can ameliorate residual type I leaks and facilitate endograft preservation.