Comparison between 3 aortic clamps for video-assisted cardiac surgery: a histological study in a pig model

To assess histological traumatic effects of aortic clamps used in video-assisted surgery, an experimental study was undertaken in a pig model, comparing the Portaclamp, Endoclamp, and a metallic clamp.

In 3 groups of 5 pigs each, the descending aorta was exposed through a posterolateral left thoracotomy. External clamps (Portaclamp and metallic clamp) were positioned at the middle of the aorta. Endoclamps were inserted at the top of the descending aorta through a small purse and inflated lower. After 60 minutes of clamping, the clamp was removed and the animal reperfused for 60 minutes. It was then sacrificed and the descending aorta was harvested for blind histological study using hemotoxylin-eosin staining of 4 samples per animal: A, before the clamping spot; B, at the clamping spot; C, after the clamping spot; D, a remote sample as control.

In the Portaclamp and metallic clamp groups, there were no lesions of the intima in all aortic samples. In the Endoclamp group, severe lesions of the intima were observed on the clamping spot: endothelium crushing with flattening of cell nucleus (3/5) or endothelium stripping with vanishing of cell nucleus all gathered in 1 point (2/5). Only spongy lesions (clearance between fibers) located on the external third of the media and moderate inflammatory lesions of the adventice were observed with a random distribution in aortic samples without difference between groups.

This study reveals the impressive lesions of the aortic intima due to the Endoclamp. The nonspecific lesions observed in media or adventice may be related to the surgical trauma of the procedure.