RESUMO
Shear has been implicated in the etiology of atherosclerosis, thrombosis and graft stenosis. We measured shear rate noninvasively in infrainguinal bypasses. Velocity profiles were recorded from 35 femoropopliteal and 40 tibial grafts. Flow rate (Q), systolic shear rate (SSR), diameter, and bluntness factor (BF) were measured at midgraft using ultrasound (US). Mean shear rate (MSR) was calculated from flow and diameter. SSR, 671 +/- 260 (SD) vs. 659 +/- 304 s(-1) (p = 0.85), and MSR, 168 +/- 84 vs. 193 +/- 110 s(-1) (p = 0.26), were similar for popliteal and tibial bypasses, but differences in Q, 126 +/- 57 vs. 104 +/- 38 mL/min, were borderline significant (p = 0.058). Popliteal grafts had larger diameters, 5.2 +/- 1.1 mm vs. 4.7 +/- 0.8 mm (p = 0.048), and BF, 3.4 +/- 0.9 vs. 2.8 +/- 0.7 (p = 0.0014). Shear rates were obtained noninvasively in humans. Larger diameters in popliteal vs. tibial bypasses did not result in lower shear rates and were compensated for by larger bluntness factors. Velocity profile bluntness cannot be ignored in shear rate analysis.
Assuntos
Artéria Femoral/diagnóstico por imagem , Hemorreologia , Artéria Poplítea/diagnóstico por imagem , Artérias da Tíbia/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Feminino , Artéria Femoral/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Poplítea/cirurgia , Fatores de Risco , Veia Safena/transplante , Sístole , Artérias da Tíbia/cirurgia , Ultrassonografia Doppler DuplaRESUMO
Nine children with the Cornelia de Lange syndrome have been examined and investigated. Prominent among the clinically important features are retarded physical and mental development, limb malformation and limited life expectancy. Early diagnosis is important for prognostication and management, and is based on the recognition of the combination of the stigmata and typical facial characteristics.