Hemodynamic and histomorphometric characteristics of heart failure induced by aortic stenosis in the guinea pig: comparison of two constriction sizes.

Heart failure induced by aortic stenosis in young guinea pigs could constitute an interesting model for pharmacology, but its natural history needs to be characterized. One hundred five guinea pigs (3-4 weeks old) underwent thoracic aortic banding with 12- (B12G) or 14-gauge (B14G) needles or similar sham operations (S12G, S14G). Animals alive at 7 d (S12G, n = 16; B12G, n = 28; S14G, n = 19; B14G, n = 27) were assessed at 60 or 120 d. At 60 d, compared with sham groups, left ventricular (LV) mass and wall thickness increased in operated groups, but LV systolic pressure and right ventricular (RV) wall thickness only increased in the B14G group. At 120 d, B12G animals still showed signs of compensated hypertrophy with LV and RV wall thickening (+8%, +21%) and LV dilation (+20%), whereas B14G animals showed signs of decompensation with LV end-diastolic pressure increase (+167%) and mean arterial pressure decrease (-28%) associated with LV and RV hypertrophy (+77%, + 51%) and greater increases of LV and RV wall thickening (+19%, + 57%), as well as LV dilation (+43%). A 12G stenosis results in compensated hypertrophy at 60 and 120 d; a 14G stenosis leads to compensated hypertrophy at 60 d and heart failure at 120 d.