Experimental Stent-Graft Treatment of Ascending Aortic Dissection

Abstract

This study assessed the feasibility of stent graft treatment of ascending aortic dissections in a porcine in vitro model. The entire thoracic aortic aorta including the supraaortic branches was harvested from 12 adult pigs and an intimal tear was artificially created. The aortic annulus was then sewn into a silicon ring of a driving chamber. The distal aorta was connected to tubing with adjustable resistance elements. The circulation was driven by a hydraulic motor piston pump to mimic aortic flow and pressure. After creating a dissection by elevating the systolic aortic pressure to 180 mm Hg, a 2- x 2.6-cm covered stent graft was inserted through the brachiocephalic trunk using a specially designed delivery system. Stent graft placement was performed under continuous ultrasound control. The longitudinal length of the created ascending aortic dissection was 1.8 +/- 0.39 cm. Ultrasound studies revealed successful deployment of the stent graft and closure of the false lumen in all 12 cases. Diameter and area of the true lumen increased from 0.52 +/- 0.15 cm to 2.54 +/- 0.36 cm (p < 0.05) and from 0.78 +/- 0.27 cm2 to 5.13 +/- 1.35 cm2 (p < 0.05), respectively. The circumference of the true lumen increased from 4.50 +/- 0.52 cm to 7.96 +/- 1.2 cm (p < 0.05). Ultrasound studies also revealed uncompromised function of the aortic valve in all cases. No dislodging of stent grafts was observed. Given ideal anatomy, experimental stent graft placement for ascending aortic dissection is feasible and achieves complete closure of the false lumen.