Aortic response to balloon-injury in the obese Zucker rat: a translational animal model for endovascular interventions

The small diameter of the carotid balloon-injury (BI) model impedes the evaluation of available endovascular devices. We developed an endovascular BI model in the rat's descending aorta that is compatible with available endovascular instruments. This study also tested the hypothesis that neointimal formation is enhanced in the aorta of obese Zucker (OZ) rats. Methods: Left external carotid arteriotomies and BI of the thoracic and abdominal aorta were performed using a Gateway balloon catheter. Aortograms and aortic pathology were examined at 2, 4 and 10 weeks. Results: Ten weeks after BI the OZ abdominal aorta narrowed 8.34 1.10 % vs. an expansion of 2.36 2.24 % in the lean rat (LZ) (p < 0.001). Simultaneously, the LZ thoracic aorta expanded 9.50 4.27 % vs. a stenosis of 2.78 1.65 % in the OZ (p = 0.003). A significant increase in neointimal formation, as measured by the intima to media (I:M) ratio, was observed in the OZ descending aorta (p <0.001). Conclusions: This is a minimally invasive BI model to the rat's descending aorta compatible with available endovascular instruments. Following BI the OZ descending aorta demonstrates enhanced neointimal formation and constrictive vascular remodeling.