Background: This study assessed the feasibility of stent graft treatment of ascending aortic dissections in a porcine in vitro model.
Methods: 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.
Results: 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.
Conclusions: Given ideal anatomy, experimental stent graft placement for ascending aortic dissection is feasible and achieves complete closure of the false lumen.