Abstract
The present research had been carried out on 32 normal aortic heart valves of the heart of
healthy indigenous cattle (Bos indicus) of Bangladesh that possessed three leaflets to
examine their gross morphological components, anatomical assessment, microscopic
structures and histochemical analysis for future bioprostheses in human. The gross
components of the aortic heart valve were the three leaflets or cusps, sinuses, interleaflet
triangles, commissures, coronary ostia, corpora arantii, annulus, aortic root and aortic wall.
Each leaflet had a central lamina fibrosa, which attached to the aortic annulus of the valve.
The parameters undertaken for anatomical assessment were: (a) number and height of the
cusps, (b) length of the lunulae, (c) width of the commissure, (d) internal and external
intercommissural distances, (e) position of the coronary ostium in relation to the aortic heart
valve and (f) position of the ventricular septum in relation to the aortic heart valve. The
assessment of the aortic heart valve showed that the mean heights of the cusps were
15.19±1.75 mm, 14.91+2.47 mm, and 14.25±2.60 mm for non coronary cusps (NCC), left
coronary cusps (LCC) and right coronary cusps (RCC) respectively. The height of NCC was
higher, followed by the LCC and the RCC. The length of the free margin of cusps of bovine
heart was 31.50±4.31 mm in NCC, 31.75-±3.57 mm in LCC and 32.22±3.10 mm in RCC
and the width of the cusps at the commissural level was 4.72±0.46 mm. in NCC, 4.47±0.57
mm. in LCC and 4.41±0.50 mm in RCC in the present study. The external intercommissural
distances were higher in all cusps of the valve than the internal intercommissural distances.
The mean external intercommissural distances of NCC, LCC and RCC were 35.06±4.29,
34.78±3.38 and 34.38±3.67 mm respectively, and the internal intercommissural distances
for NCC, LCC and RCC were 21.13±4.44, 22.09±4.65 and 21.56±4.79 mm respectively.
The left coronary ostia emerged from the left coronary sinus and the right one from the right
coronary sinus. The mean diameter of the aorta of bovine heart was 23.20±2.91 mm, and
there were no significant sexual differences, but the diameter increased progressively with
the increase in age. The mean weight of the heart in the present study was 606.25 g.
Hematoxylin and Eosin stain showed that the leaflet or cusps of aortic heart valve of bovine
heart composed of fibrosa, spongiosa and ventricularis. The fibrosa was a layer of dense
collagenous fibrous tissue subjacent to the endothelium of the aortic surface. The spongiosa
was a thin layer of loose mesenchymal tissue between the fibrosa and ventricularis. The
ventricularis was a layer of elastic tissue subjacent to the endothelium of the ventricular
surface. Both the fibrosal and ventricular surface of the cusps of the aortic heart valve were
lined by endothelium. The arrangement of the lining epithelium of the cusps was
perpendicular to the blood flow of the left ventricular outflow tract of the bovine heart The
Verhoeff's Elastic Stain revealed that the abundant collagen fibres were found in the
fibrosa, aortic root and aortic annulus of aortic heart valve of bovine heart, and the
prominent black elastic fibres were found in the ventricularis of the leaflet of aortic heart
valve, aortic wall and ascending aorta of bovine heart in the present study. By using PAS
stain, the positive materials were found in the spongiosa of the leaflet and aortic annulus of
aortic heart valve. The chondrogenic plate or cartilaginous plaques containing chondroid
cells of hyaline in nature were found in the aortic annulus. The coarse collagen bundles
towards the ventricular myocardium were also found in the aortic annulus of aortic heart
valve of bovine heart. The blood vessels, capillaries and lymphocytes were found in the
aortic annulus, aortic wall and ventricular myocardium. The cusps of the aortic heart valve
of bovine heart were devoid of blood vessels or capillaries. Histologically, the cusps of both
bovine and human aortic heart valve were similar but the difference was only in their
thickness. The bovine aortic cusp was thicker than the cusp of human aortic heart valve and
it was 193 µm and 145 µm respectively. The gross study, anatomical assessment, and
histological characteristics of the aortic heart valve of bovine heart in the present study
indicate the possible prospect of manufacturing the bovine tissue valves that might be
clinically applied in cardiac valve replacement in human.