Experimental evaluation and early clinical results of a new low-profile bileaflet aortic valve

A naturally shaped silicone ventricle evaluated in a mock circulation loop: a preliminary study

Mock circulation loops are used to evaluate the performance of cardiac assist devices prior to animal and clinical testing. A compressible, translucent silicone ventricle chamber that mimics the exact size, shape and motion of a failing heart is desired to assist in flow visualization studies around inflow cannulae during VAD support. The aim of this study was therefore to design and construct a naturally shaped flexible left ventricle and evaluate its performance in a mock circulation loop. The ventricle shape was constructed by the use of CT images taken from a patient experiencing cardiomyopathic heart failure and used to create a 3D image and subsequent mould to produce a silicone ventricle. Different cardiac conditions were successfully simulated to validate the ventricle performance, including rest, left heart failure and VAD support.

Eight-year follow-up after prospectively randomized implantation of different mechanical aortic valves

OBJECTIVE

The aim of this prospectively randomized study was to evaluate the hemodynamic and functional outcomes after aortic valve replacement with three different bileaflet mechanical valves.

METHODS

From March 1996 to August 1998, 300 consecutive patients were randomly assigned to receive ATS (n = 100), Carbomedics (n = 100), or St Jude Medical Hemodynamic Plus (n = 100) mechanical aortic valve replacement. There were no significant differences regarding patient age (61 +/- 8 years), gender, NYHA, aortic valve pathology, ventricular morphology, ejection fraction and requirement for additional procedures at implant. Mean follow-up extends to 95 +/- 21 months at a total of 2,891 patients years and is in 95.3% complete.

RESULTS

Implanted valve sizes were comparable at 24 +/- 2 mm (ATS), 23.7 +/- 1.6 mm (CM), and 23.6 +/- 1.9 mm (SJMHP) (NS). Follow-up results were: transvalvular flow velocities 2.3/2.3/2.2 m/s, ejection fraction 64/59/63%, trivial transvalvular incompetence 3/3/2; paravalvular leak 2/3/2; freedom of reoperation 100/99/99%, NYHA functional status 1.5/1.8/1.6, overall survival 86.4/82.8/80.6%, freedom from thrombembolic events 100/96/98%, freedom from hemorrhage 100/100/99%, freedom from all valve related events was 100/96/98%; respectively (NS). There were no episodes of endocarditis. Ninety-four percent of the patients were satisfied with the procedure enjoying an enhanced daily life activity.

CONCLUSIONS

There are no clinically relevant differences among the tested bileaflet aortic valves. Regardless of valve type, there was a rather low complication rate in this relatively young population. All three bileaflet prostheses are well suited for aortic valve replacement.