This paper describes "how to" examine cardiac valves with computed tomography, the normal, diseased valves, and prosthetic valves. A review of current scientific literature is provided. Firstly, technical basics, "how to" perform and optimize a multislice CT scan and "how to" interpret valves on CT images are outlined. Then, diagnostic imaging of the entire spectrum of specific valvular disease...

In this study, we report on our first experience with the construction of a valve using autologous vena cava tissue for right ventricular outflow tract reconstruction. Simulating the clinical situation valves were built from tubular pieces of porcine inferior vena cava placed in a PTFE tube and investigated in a pulsatile flow simulator. Based on the given vena cava dimensions, conduits were co...

We studied the function of right internal jugular vein valves during cardiac catheterization in 32 patients and external jugular vein valves in vitro from 13 dogs. Patients with normal central venous pressure had competent valves during cough-induced transvalvular pressure gradients of 52.4 +/- 8.6 mm Hg. Ten of 15 patients with elevated central venous pressure had either incompetent or absent ...

To investigate the mechanism that increases the orifice area of the mitral valve during balloon dilatation 43 surgically excised intact rheumatic mitral valves were studied. The main pathological features were (a) fibrosis of mitral valve leaflets and commissures (10 valves); (b) fibrosis with calcification of one commissure (eight anterolateral, seven posteromedial); (c) fibrosis with calcific...

At the Niigata University Hospital, various kinds of prosthetic valves such as the Starr-Edwards nonclothand cloth-covered, Bjork-Shiley tilting disc, and Carpentier-Edwards porcine valves, have been used from September, 1965 to March, 1979 for replacement of diseased valves on 176 patients. The patients with Starr-Edwards nonclothand cloth-covered ball valves showed survival rates of 90 and 84...

BACKGROUND In vivo studies have shown that valves in veins are paired in an orthogonal configuration. The aim of this study is to characterize the flow interaction of paired valves under controlled in vitro bench conditions. METHODS A bench top in vitro experiment was set up at physiological flow conditions to simulate the flow inside a venous valve. Two bicuspid bioprosthetic valves paired i...

The Doppler echocardiographic characteristics of 70 prosthetic valves in 35 patients are reported. Twenty nine patients had a Björk-Shiley prosthesis in both mitral and tricuspid positions and six had Carpentier-Edwards valves in both sites. Five of the patients had abnormal tricuspid prostheses on the basis of clinical and echocardiographic criteria. Pulsed wave Doppler echocardiography was us...

Conventional electro-hydraulic precision motion control systems are controlled by either servo valves or proportional directional control valves. Neither of the valves are able to control the pressures at the two cylinder chambers independently or to use the regeneration flow. The result is that while precision motion control is possible, significant energy saving is not. In order to save energ...

2542 B ioprosthetic valves are increasingly used in patients with aortic stenosis. Compared with mechanical valves, bio-prosthetic valves are associated with a lower risk of thrombo-embolic events and do not require long-term anticoagulation. 1,2 However, bioprosthetic valves have limited durability; the best current valves can be expected to degenerate within 10 to 20 years, resulting in steno...

The present study was undertaken to find an antibiotic mixture which would rapidly and completely sterilize a heavily contaminated allograft heart valve without reducing its viability. Two different antibiotic combinations were used; formula A was used for 66 valves and formula B for 60 valves. Viability of the valves was assessed by autoradiography and tissue culture, and was found to be simil...