Evaluation of low-pressure arterial and venous clamps: electron microscopic study and possible clinical applications.

These authors report on validating their choice of disposable clamps in arterial and venous microsurgery in a comparative and experimental study using the scanning electron microscope. This appears to be the first evaluation of venous endothelial clamping lesions. Early intimal clamping lesions were studied using three different clamps and two protocols in 18 femoral arteries and veins in rabbits. Results were evaluated using a new classification that can be applied to both arterial and venous lesions: Grade I: cellular disorientation and disorganization; endothelial lamination; and absent or very few platelet deposits; Grade II: alterations of the cytoplasmic membranes in fusiform cells; presence of at least one breach of endothelial continuity; and moderate number of platelet deposits; Grade III: presence of endothelial detachment; and large numbers of platelet deposits. They showed that in arteries, all the clamps tested caused only low-grade lesions. In contrast, in veins, they demonstrated both the very fragile nature of the endothelium, and also the comparative safety of the low-pressure venous clamp. Their choice of specific clamps for venous anastomoses was validated.