Early clinical experience with a new tubular equine pericardial stentless aortic valve

Tissue-engineered fibrin-based heart valve with a tubular leaflet design

The general approach in heart valve tissue engineering is to mimic the shape of the native valve in the attempt to recreate the natural haemodynamics. In this article, we report the fabrication of the first tissue-engineered heart valve (TEHV) based on a tubular leaflet design, where the function of the leaflets of semilunar heart valves is performed by a simple tubular construct sutured along a circumferential line at the root and at three single points at the sinotubular junction. The tubular design is a recent development in pericardial (nonviable) bioprostheses, which has attracted interest because of the simplicity of the construction and the reliability of the implantation technique. Here we push the potential of the concept further from the fabrication and material point of view to realize the tube-in-tube valve: an autologous, living HV with remodelling and growing capability, physiological haemocompatibility, simple to construct and fast to implant. We developed two different fabrication/conditioning procedures and produced fibrin-based constructs embedding cells from the ovine umbilical cord artery according to the two different approaches. Tissue formation was confirmed by histology and immunohistology. The design of the tube-in-tube foresees the possibility of using a textile coscaffold (here demonstrated with a warp-knitted mesh) to achieve enhanced mechanical properties in vision of implantation in the aortic position. The tube-in-tube represents an attractive alternative to the conventional design of TEHVs aiming at reproducing the valvular geometry.

Falsely elevated valve gradients by echocardiography in the 3f aortic bioprosthesis

The 3f Aortic Bioprosthesis (Medtronic, Inc, Minneapolis, MN) is a stentless aortic valve with a novel design that resembles a "tube within a tube." Although it has the potential for improved durability and hemodynamic performance, long-term data on this valve remain elusive. We present here 3 patients in whom postoperative echocardiography revealed significantly elevated transvalvular gradients of the 3f valve while transcatheter gradients proved to be negligible. By virtue of the unique design of the 3f bioprosthesis, great caution should be taken when interpreting echocardiographically derived gradients.

Leaflet replacement for aortic stenosis using the 3f stentless aortic bioprosthesis: midterm results

BACKGROUND

The 3f aortic bioprosthesis is a stentless valve resembling the native aortic valve. It has been postulated that improved hemodynamic performance with this prosthesis may translate into superior durability. We hereby report the midterm results using this valve substitute.

METHODS

Fifty patients with severe aortic stenosis received the 3f aortic bioprosthesis between 2002 and 2004 in our unit. Clinical outcomes, effective orifice area, mean gradients, and ejection fraction were evaluated at discharge, at 6 and 12 months, and yearly thereafter.

RESULTS

Mean follow-up was 52 ± 10 months and was complete in 96% of surviving patients. Hemodynamic performance of the 3f valve was satisfactory for substitutes in the range of 25 mm and 27 mm; smaller valve substitutes showed unfavorable hemodynamic performance with mean gradients of 18 ± 7 mm Hg for 21-mm prosthesis, and 14 ± 5 mm Hg for 23-mm prosthesis. Consequently, the regression of left ventricular hypertrophy was incomplete. Late mortality included 10 patients (valve-related in 1, cardiac-related in 3) for a survival of 77% ± 3% at 4 years. Four patients required reoperation owing to endocarditis in 2 and paravalvular leak in other 2. Freedom from reoperation was 93% at 4 years. Six patients experienced 9 neurologic events, accounting for 82% freedom from neurologic events.

CONCLUSIONS

Its unique design makes the 3f aortic bioprosthesis less complex to implant than conventional stentless valves, as only a single suture line is necessary. The hemodynamic profile and clinical performance of the prosthesis are inconsistent with the established stentless valves, especially with regard to higher incidence of neurologic complications seen during the follow-up.

3f prosthesis aortic cusp replacement: implantation technique and early results

Stentless aortic bioprostheses have been successfully used for over a decade. The 3f bioprosthesis is a new equine pericardial stentless valve, unique in its tubular design, preserving the native aortic sinuses post-implant. Forty-six consecutive aortic valve replacements with the 3f bioprosthesis were performed between June 2003 and January 2005. The patients were prospectively assessed and echocardiography was performed at 6 months, 12 months, and annually thereafter. The median follow-up was 2.1 + or - 0.9 years. There was one early and 4 late deaths; none were valve-related. The 2-year mean transvalvular gradient was 8.8 + or - 3.8 mm Hg, the mean echocardiographic aortic regurgitation grade was 0.4 + or - 0.7 (grade 1 being trivial). Echocardiographic sizing of the aortic annulus before surgery accurately predicted prosthesis size. The 3f bioprosthesis is easy to implant. Early clinical results are favorable, with hemodynamic profiles consistent with those of other stentless prostheses. Longer follow-up is required to confirm its durability.