Animal model of ascending aortic stenosis in rabbits without endotracheal intubation

Experimental animal studies of left ventricular hypertrophy (LVH) usually involve endotracheal intubation, which is associated with a risk of serious tracheal injury and other significant negative sequelae. We developed an animal model of pressure overload hypertrophy caused by constriction of the ascending aorta in rabbits that does not require endotracheal intubation.

New Zealand White rabbits of either sex (1.94 +/- 0.12 kg) were randomly assigned to the aortic banding (AB) group (n = 9) and the sham-operated group (n = 8). The sternum was carefully incised along the midline to avoid injury to the parietal pleura. Then, the intervention group underwent AB with three to zero Prolene proximal to the innominate artery without endotracheal intubation. To investigate the effects of the surgical procedure on physiological parameters, echocardiography, histology, and electron microscopy were performed to assess functional and structural hypertrophy at various time intervals.

Banding of the ascending aorta created the expected increases in both aortic velocity and the pressure gradient between proximal and distal aorta coarctation. The pressure overload resulted in a robust LVH assessed by transthoracic echocardiography and histology. The animals did not experience severe mechanical ventilatory impairment.

We developed a safe, efficient, and reproducible method of producing LVH in rabbits without the need for endotracheal intubation and mechanical ventilation. Ultimately, this model will facilitate focused study of the mechanisms involved with LVH progression.