Endovascular treatment of wide-neck saccular renal artery aneurysm with waffle-cone technique

Abstract In the past, treatment of visceral artery aneurysms (VAAs) was exclusively surgical. These aneurysms were rarely diagnosed in elective or emergency cases. Development of imaging techniques and endovascular procedures has changed the history of the therapeutic options for this pathology. Endovascular management of VAAs has arisen to advances in endovascular techniques and has achieved high efficacy.


PART I -CLINICAL SITUATION
A 62-year-old woman presented with a saccular renal artery aneurysm. She was asymptomatic and diagnosis was the result of a finding during a regular clinical check-up. She had an intraparenchymal renal saccular aneurysm, measuring 2.7 x 2.0 cm and with a large aneurysm neck length (> 4mm), which would need a remodeling technique to exclude the aneurysm sac ( Figure 1).

PART II -WHAT WAS DONE
Our treatment approach was SACE using a wafflecone technique 1-10 ( Figure 1). Access was obtained, the right common femoral artery was punctured using the Seldinger technique, and a 6Fr sheath was positioned in the left renal artery. A Prowler Select Plus ® microcatheter was then positioned inside the aneurysm and a 4.5 x 27 mm Enterprise ® (Cordis, Miami, FL, USA) self-expandable stent was implanted into the aneurysm, intentionally covering the bifurcation.   Using a coaxial technique, a Prowler ® microcatheter was advanced into the aneurysm through the stent lumen for coiling ( Figure 2). A total of 12 Trufill DCS Orbit coils ® were then deployed by controlled release. Digital subtraction angiography demonstrated complete occlusion of the aneurysm after stent assisted coiling (Figures 3 and 4).
Final control arteriography demonstrated the aneurysm completely occluded ( Figure 5). Control CT showed successful exclusion of a 2.7 x 2.0 cm saccular intraparenchymal renal aneurysm ( Figure 6). The patient was given dual antiplatelet therapy after the procedure. She gave her consent to publication of her case details and images.

DISCUSSION
Several stent-supported coiling techniques have been used to treat wide-necked bifurcation aneurysms, including waffle-cone constructs. [2][3][4][5] First conceived in neuro-interventional practice, the differentiating factor with this technique is that it uses the stent as support to guide positioning of the coils to prevent prolapse during deployment and to help packing, resulting in a stable scaffold jailing the coils in the aneurysm sac. [2][3][4][5][6][7][8] The diameter of the nitinol stent is determined based on assessment of the size of the aneurysm neck and the diameter of the proximal parent artery. The wafflecone is thus created by deploying the stent's proximal end within the renal artery and the distal end at the proximal extreme of the aneurysm. This placement avoids migration of the coils and allows good flow through the division branches. Liu showed that the waffle cone technique is an effective alternative tool for stent-assisted coiling of complex, wide-necked bifurcation aneurysms with unfavorable anatomies. 7 Authors have determined criteria to define an approach to difficult aneurysms with aspect and dome-to-neck ratio <1.2mm, and a neck width >4.0 mm. 10 In our decision, the ratio measurement determined during  preoperative planning was the independent predictor for an adjuvant technique.
In conclusion, endovascular treatment of VAAs with stent-assisted coiling is a viable and safe procedure that is effective for treating complex wide-necked bifurcation renal artery aneurysms whose anatomic features are unfavorable for conventional coiling. [1][2][3][4][5] The Waffle-Cone technique seems to be a technical option with effective arterial remodeling. However, long-term follow-up results are needed for evaluation.