Assessment of transmural force during application of vascular occlusive devices

An in vivo system was established whereby the transmural forces exerted across the arterial wall during vascular occlusion were directly measured. Evaluation of various currently available vascular occlusive devices was conducted and transmural force transmission data were recorded. The clamps were classified according to their mechanical design characteristics. The magnitude of force required to obtain cessation of distal flow varied significantly among devices of differing mechanical design but correlated well when compared with clamps of similar design. This information was then compared with graded analysis of the degree of intimal injury created by these specific devices as assessed with scanning electron microscopy. The amount of transmural force exerted by each individual device correlated with the grade of intimal injury created by that device. We conclude that fundamental clamp design dictates the magnitude of applied transmural force, that force and the vectors of the application of that force are directly responsible for the degree of resultant intimal injury, and that the intima appears to possess an injury threshold of approximately 5 x 10(4) dynes/cm2. Intimal injury may determine success or failure of vascular surgical procedures; therefore it is prudent to seek the least traumatic means of vascular occlusion.