Induced moderate-to-severe chronic aortic regurgitation resulted in congestive heart failure in 54.5% of rabbits, which was strongly associated with myocardial fibrosis and myocyte necrosis.
Does chronic experimental aortic regurgitation induce myocardial fibrosis and myocyte degeneration associated with heart failure in a rabbit model?
Chronic experimental aortic regurgitation in rabbits leads to heart failure that is strongly associated with myocardial fibrosis and myocyte necrosis, suggesting a pathophysiological link.
Myocardial fibrosis and myocyte degeneration have been reported in patients with chronic aortic regurgitation (AR), and may be related to the pathophysiology of congestive heart failure (CHF) in this disease. To define the relationship between myocardial histopathologic variations and CHF in chronic AR, we performed gross and microscopic evaluations of postmortem tissue from a rabbit model of chronic AR manifesting left ventricular (LV) responses to AR similar to those in humans. Moderate-to-severe chronic AR (echocardiographic regurgitant fraction = 52 +/- 13%) was induced by closed-chest aortic valve perforation in 11 New Zealand White rabbits; 5 control rabbits were sham operated. Six of the 11 AR rabbits died 1.5 +/- 0.8 years (range 0.6-2.8 years) after AR induction; all 6 had gross and histologic anatomic evidence of CHF at necropsy. The remaining 5 AR rabbits survived until sacrifice at 2.9 +/- 0.1 years of AR; none had pathologic evidence of CHF. Cardiac hypertrophy and the extent of LV fibrosis and myocyte necrosis all were greatest among the 6 AR CHF rabbits. No inflammatory response was apparent in any animal. Moderate-to-severe chronic experimental AR frequently results in CHF which is strongly associated with myocardial fibrosis and necrosis, without evidence of inflammation. These histopathologic variations may be pathophysiologically related to CHF development.
Liu et al. (Thu,) conducted a other in Chronic aortic regurgitation (n=16). Induced moderate-to-severe chronic aortic regurgitation vs. Sham operation was evaluated on Congestive heart failure and myocardial histopathologic variations (fibrosis and myocyte necrosis). Induced moderate-to-severe chronic aortic regurgitation resulted in congestive heart failure in 54.5% of rabbits, which was strongly associated with myocardial fibrosis and myocyte necrosis.