EVAR is a minimally invasive modality for AAA treatment associated with a reduced perioperative mortality rate compared to open repair. For those reasons EVAR has become the preferred option in infrarenal AAA repair, but long-term follow-up suggests that the survival benefit from EVAR is lost, due to a higher rate of reinterventions .
The causes of EVAR failure are multifactorial, depending upon anatomy features, inaccurate preimplantation planning and deployment or device failure.
The ZC endograft has demonstrated a durable repair of AAA, with a low aneurysm-related mortality and an acceptable rate of reinterventions.
However, the junction between the suprarenal bare stent and the proximal part of the main body the graft may represent an area of weakness, and disconnections of the proximal uncovered stent have been reported with the first generation of this device prior to 2002 [2–3]. At that time, the stent graft was modified with a double-suture reinforcement to secure the uncovered stent. Since this modification was introduced, uncovered stent disconnection has become very rare, as even reported by Torres-Blanco et al. and Lindstrom et al. [4–5].
So far, no cases of disconnections of the newest generation of ZC devices, the Zenith Alpha, have been reported. Our case, however, shows that this issue has not definitively been resolved with this new generation of endograft.
In our case, despite an initial AAA sac shrinkage, the disconnection occurred only two years after EVAR, while previous reports have shown this complication to occur 3–8 years after treatment [4–7].
Careful re-review of preoperative planning confirmed endograft sizing within the manufacturer’s instructions for use and the anatomy gives no direct hints on why this endograft failed. The endograft implantation was retrospectively analyzed step-by-step without evidence of problems. The proximal site of sealing was ballooned within the first covered stent, and the balloon was inflated in accordance with its IFU.
This case has been reported to Cook Medical, in order to improve current products and future designs, and an investigation has been initiated.
In our case, no endoleak was detected at imaging, although the evident sac enlargement represented the sign of the endotension caused by the failed proximal seal.
A thoracic endograft was used in this case to span the distance from renal artery to the bifurcation of main body and obtain a complete relining. The length of the thoracic graft was 80 mm, and it seemed to be a more appropriate device to ensure the maximum overlap and the greatest columnar strength.