Thoracic aortic aneurysm formation with the use of CaCl2: an experimental model in rabbits

Introduction: Thoracic aortic aneurysms (TAA) remain a serious condition with both high morbidity and mortality rates. Further understanding of the pathophysiology and progression of TAAs may provide less invasive diagnostic techniques and therapeutic strategies in patients with this alarming disease. The objective of the present study was to establish a reproducible rabbit model of thoracic aortic aneurysm with the use of CaCl 2. Methods: Adult New-Zealand rabbits were subjected to posterolateral thoracotomy and were allocated into 2 groups: Control group ( n =4): a NaCl solution was applied on the external wall of descending thoracic aorta (sham surgery), and CaCl 2 -treated group ( n =8): a solution of 0.5 mol/L CaCl2 was applied on the external wall of descending thoracic aorta. Results: Twelve weeks of CaCl 2 treatment resulted in an average 21% increase in the aortic diameter (4876±617 μm vs 3856±604 μm, p = 0.022) and in an decrease in wall thickness(366±107 vs 280±72, p >0.05 ) compared to the aorta segments of untreated animals. Although no statistical significance was achieved, aortas treated with CaCl 2 presented apparent atherosclerosis in 75% of the cases, while only 20% of the control aortas were found atherosclerotic. Conclusions: This study demonstrates for the first time the creation of a reproducible animal model of TAA in rabbits that recapitulates pathological changes attributed to humans.