Evaluation of Low-Pressure Arterial and Venous Clamps: Electron Microscopic Study and Possible Clinical Applications

Abstract

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.

Development and hemocompatibility testing of nitric oxide releasing polymers using a rabbit model of thrombogenicity

“…However, to date, what specific in vitro or in vivo assays provide the best information for a complete picture of the biomaterial blood compatibility is lacking. The current standard developed by the International Organization for Standardization (ISO) that guides investigators on testing biomaterials and medical devices for hemocompatibility is ISO 10993-4 which is entitled “Selection of Tests for Interactions with Blood.” 92–97 ISO 10993-4 provides a structured test selection system that is based on clinical concerns which suggest categories of hemocompatibility that should be determined, including thrombosis, coagulation, platelet count and function, hematology, and immunology. Specific tests are available to assess a biomaterial's potential to elicit adverse effects in these categories of blood function with the ultimate goal of ensuring biomaterials and/or medical devices are safe for use in patients.…”

A critical review of surgical strategies to minimise venous stenosis in arteriovenous grafts

“…The impact of the method of control has been shown to influence the degree of initial venous intimal injury, though it is never recorded in the literature of AVG outcomes. 67 Similarly, there is little evidence available reporting on the differential effects on the endothelium of the method employed. In a comparative study comparing the effect of a silicon sloop with a metal clamp in both normal and diseased vessels, silicon sloops demonstrated significantly less endothelial injury when compared with metal clamps.…”

Valoración del daño parietal a nivel vascular, tras la aplicación de métodos extraluminales de oclusión temporal

“…En este trabajo se evidencia una mayor afectación de la capa media en las arterias clampadas con fuerzas oclusivas altas (0.30 N) que en las venas. Durand y colaboradores (163) compararon la respuesta de arterias y venas utilizando clamps desechables de baja presión. Ellos demostraron que en las arterias, todos los sistemas probados causaron solamente lesiones de bajo grado.…”

“…Kühnel et al (12) observaron mayor severidad en el daño por el incremento en la fuerza de oclusión que por la duración de la misma. La importancia de la fuerza oclusiva, proporcional directamente al daño ya había sido descrita en es-tudios comparativos del daño producido por diferentes tipos de clamps (10) y en estudios sobre la acción de la fuerza oclusiva de los dispositivos (163)(164)(165)(166)(167) . El trabajo de Kühnel difiere de los resultados obtenidos por Babin (2) (11) que revelan que la reconstitución y regeneración del endotelio es muy rápida tras la lesión por el clamp.…”