RESUMEN
Endovascular treatments for catastrophic aortic conditions have gained increasing popularity over the past 20 years. Originally developed for abdominal aortic aneurysms (EVAR), treatment has been modified for use in thoracic aortic repair (TEVAR). As expanding numbers of patients with increasingly intractable conditions and more hostile anatomies are treated, endovascular stent designs are maturing to be suitable for these more demanding situations. This article discusses the engineering considerations that apply to changing stent graft designs for current and evolving thoracic applications. The biological parameters that differentiate thoracic from abdominal aortic environments are outlined. Factors concerning materials, sealing mechanisms, deployment, stent frame architecture, and migration resistance are described, and eagerly awaited potential future developments are summarized.
Asunto(s)
Aorta Torácica/cirugía , Implantación de Prótesis Vascular/instrumentación , Prótesis Vascular , Procedimientos Endovasculares/instrumentación , Diseño de Prótesis , Stents , Animales , Aorta Abdominal/cirugía , Prótesis Vascular/historia , Prótesis Vascular/tendencias , Implantación de Prótesis Vascular/efectos adversos , Implantación de Prótesis Vascular/historia , Implantación de Prótesis Vascular/tendencias , Diseño Asistido por Computadora , Procedimientos Endovasculares/efectos adversos , Procedimientos Endovasculares/historia , Procedimientos Endovasculares/tendencias , Predicción , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Complicaciones Posoperatorias/prevención & control , Diseño de Prótesis/historia , Diseño de Prótesis/tendencias , Falla de Prótesis , Stents/historia , Stents/tendencias , Resultado del TratamientoRESUMEN
In the present article, recent research efforts in our laboratory to improve cryosurgery by use of mechanistically derived adjuvants are reviewed. Our research has been focused on enhancing two freezing induced injury mechanisms - i) direct cell injury by use of thermophysical adjuvants, and ii) vascular injury by use of an inflammatory adjuvant. The thermophysical adjuvants are chemicals, usually salts, which can induce secondary crystallization, called eutectic solidification, in a cryolesion; thereby enhancing direct cell injury. The inflammatory adjuvant is a cytokine, tumor necrosis factor-alpha (TNF-alpha), which upregulates inflammation of microvasculature in tumors prior to freezing to promote vascular injury in the cryolesion. Even though the individual mechanism of injury enhancement within the cryolesion of each adjuvant requires further study, both adjuvants are envisioned to enlarge the complete killing zone so that the boundary of the cryolesion matches more closely with the edge of iceball. By bringing the edge of the cryolesion closer to the edge of iceball, the adjuvants hold promise for improvement of image guidance and outcome of cryosurgery.