Unequal pressure distribution along the jaws of currently available vascular clamps: Do we need a new aortic clamp?

Abstract

Objectives: The pressure along vascular clamp jaws may be unequally distributed, with greater pressure near the clamp hinge than at itstop. Such unequal pressure distribution may cause aortic injury, especially in large aortas. We evaluated pressure distribution along differentcurrently availably clamp jaws.Methods: Seven descending thoracic aortas from pigs (diameter 2.0-3.0 cm) were plainly dissected and all side arteries closed. Aortaswere filled up with water and cross-clamped. The pressure inside the aorta was raised to 100 mmHg and the aorta was clamped so tightlythat no water exited from the distal aortic end. Each aorta was clamped seven times at different sites with the following clamps: DeBakey,Satinsky, femoral, iliac, Chitwood, angled handle Fogarty and straight handle Fogarty. The pressure along the clamp jaws was measuredwith a pressure-detecting film placed between the clamp jaws and aorta. The collagen-fibre disorganization was examined in haemotoxylin-eosin- and Elastica van Gieson-stained tissue samples.RESULTS: The DeBakey clamp revealed the lowest maximum pressure along the clamp jaws after complete aortic occlusion (1.43 ± 0.49 MPa),whereas the Chitwood clamp's pressure was the highest (3.26 ± 1.93 MPa, P < 0.001). The angled handle Fogarty clamp displayed thelowest difference between maximum pressures across the jaws (33%), with the greatest difference measured in the iliac (72%) andChitwood (66%) clamps. The highest collagen-fibre disorganization score was observed in the proximal-to-the-clamp-hinge quartile afterclamping with the angled handle Fogarty (2.8 ± 0.4), straight handle Fogarty (2.3 ± 0.8) and Chitwood (2.3 ± 0.5) clamps.Conclusions: The pressure along clamp jaws is unequally distributed in all the currently available vascular clamps. The Chitwood clamp is associatedwith the highest maximum pressure during complete aortic occlusion and with the most unequal pressure distribution along the jaws.