Comparison of latest tissue valves

[Andyrdj]

http://icvts.ctsnetjournals.org/cgi/content/full/5/suppl_2/S187

Many studies on this page, but two I wish to pick out in particular.

Study 1, in patients after one year, seems to favourably compare the Haemodynamics of The C/E magna verses the medtronic mosaic valve.

Study 2, performed in vitro (obviously with high concentration calcium solution) seems to favour the Mosaic Ultra valve over the C/E magna in terms on anticalcification and performance when calcified, adding that both are significantly better than previous ones.

A key question to ask, if anyone knows, is what changes there have been between the old medtronic mosaic and the new ultra valve. New anticalcification process? Better Haemodynamics? These things are key points as I'm assuming that study1 is based on the old mosaic.

A pity that one valve couldn't have been better in both, as it now becomes a weighing act to choose between them. However, we could really do with seeing if we can find some independant studies to back up these claims. Please search and post, people!

http://icvts.ctsnetjournals.org/cgi/content/full/5/suppl_2/S187
231 - O ONE YEAR HAEMODYNAMIC PERFORMANCE OF THE PERIMOUNT MAGNA AND THE MEDTRONIC MOSAIC BIOPROSTHESIS IN THE AORTIC POSITION: A PROSPECTIVE RANDOMISED STUDY
M.J. Dalmau1, J.M. González-Santos1, J. López-Rodríguez1, M. Bueno1, A. Arribas2, F. Nieto2
1Department of Cardiac Surgery, Salamanca University Hospital, Salamanca, Spain; 2Department of Cardiology, Salamanca University Hospital, Salamanca, Spain
Objectives: To compare the haemodynamic performance of the Edwards Perimount Magna (EPM) pericardial xenograft and the Medtronic Mosaic (MM) porcine bioprosthesis. Comparison was performed according to the patient aortic annulus diameter.
Methods: Eighty-six patients undergoing aortic valve replacement were prospectively assigned to receive either an EPM valve (n=43) or a MM bioprosthesis (n=43). Intraoperative randomisation was performed after the aortic annulus diameter was measured with three different sizers (EPM, MM and a Hegar dilator). Patients were grouped according to their aortic annulus diameter in <22 mm (n=13), 22?23 mm (n=31) and >23 mm (n=42). Echocardiographic assessment was performed 1 year postoperatively.
Results: The mean aortic annular diameter (EPM 23.8±2.1 mm vs. MM 23.6±2.3 mm) and mean valve size implanted (EPM 22.6±2.1 mm vs. MM 23.3±2.1 mm) were comparable in both groups. The EPM-group showed significantly lower mean gradient (EPM 10.0±3.1 mmHg vs. MM 17.2±8.3 mmHg) and larger effective orifice area (EOA) (EPM 1.97±0.4 cm2 vs. MM 1.67±0.4 cm2, P<0.0001). The EPM-valve was superior with respect to mean pressure gradient and EOA in all aortic annular diameters. This difference was statistically significant in patients with an annulus diameter of 22?23 mm (EPM 9.8±2.5 mmHg vs. MM 18.2±8.8 mmHg; EPM 1.76±0.3 cm2 vs. MM 1.52±0.2 cm2) and >23 mm (EPM 9.4±3.0 mmHg vs. MM 14.1±5.6 mmHg; EPM 2.17±0.3 cm2 vs. MM 1.90±0.4 cm2). Patient-prosthesis mismacht (EAOI < 0.85 cm2/m2) was present in 26.3% (MM) vs. 8.1% (EPM) of the patients (P=0.03).
Conclusions: When the same aortic annulus diameter is taken as a reference, the EPM-valve was haemodynamically superior to the MM-bioprosthesis. The use of the EPM-prosthesis significantly reduced the incidence of PPM.


236 - O CHANGES IN HAEMODYNAMIC PERFORMANCE AND LEAFLET KINEMATICS WITH PROGRESSIVE CALCIFICATION OF PORCINE VERSUS PERICARDIAL AORTIC VALVES
P. Kleine1, O. Dzemali1, F. Bakhtiary1, C. Schmitz2, U. Steinseiffer2, B. Glasmacher2, A. Moritz1
1Department of Thoracic and Cardiovascular Surgery University Hospital, Frankfurt am Main, Germany; 2Helmholtz Institute for Applied Medical Engineering, Aachen, Germany
Objectives: In vitro testing of biological valves has only been performed using fresh valves. The following study investigates changes in haemodynamic performance and leaflet kinematics in progressively calcified pericardial and porcine aortic valve prostheses.
Methods: Edwards Perimount Magna (PM, n=5) and Medtronic Mosaic Ultra (MU, n=5) heart valves (23 mm) were investigated in a pulse duplicator (70 beats/min, Cardiac Output 5 l/min). Leaflet kinematics were visualised with a high-speed camera (3000 frames/s). Following valves were exposed to a Calcium phosphate solution at a constant pulse rate of 300/min for a total of 6 weeks. Repeated testing was performed after 1, 2, 3, 4 and 6 weeks of calcification.
Results: Initially PM demonstrated lower pressure gradients compared to the MU (9.7±1.2 vs. 14.0±1.1 mmHg), but a higher closing volume (7.2±1.4 vs. 1.8±0.4% of stroke volume) leading to an equivalent total energy loss (8.9±1.4 vs. 9.0±1.5%). PM then calcified significantly faster and more severe leading to an increase in gradients (12.6±1.4 after 6 weeks). Leaflet kinematics showed progressively longer opening and closing times for the pericardial valves (closing time PM 135±11 msec vs. MU 85±9 ms after 6 weeks).
Conclusions: Despite the new ThermaFix tissue treatment Perimount Magna pericardial valves calcified in vitro faster and more severe than Mosaic Ultra porcine valves, which demonstrated a constant performance throughout the calcification process. Leaflet kinematics showed a progressive prolongation of opening and closing times for pericardial valves leading to higher closing volume. Both valve performed superior to previously tested biological valve substitutes.

 

[tobagotwo]

The CEPM has a lower pressure gradient than the Medtronics Mosaic. That's a long-established fact. At three to five years, here are some typical in vivo pressure gradients, taken from graphs from the valves' own sites. In vivo means in the living body, vs. in vitro which means in an artificial environment. I'll use the 25mm model, as that's the most common size:

Pyrolytic Carbon:
Carbomedics: 8.3
On-X: 4.2
St. Jude: 6.1

Tissue:
Carpentier-Edwards Perimount: 12.5
Toronto SPV: 6.1
Freestyle: 4.9
Mosaic 13.4

All are measured in mmHG (millimeters of mercury).

All of these valves (and the ATS for which I couldn't get gradient numbers above the #19) produce excellent ventricular remodelling, indistinguishable from each other after six to eight months. As they say, "It's all good."

While the study of these valves in a "test tube" environment, bathed in calcium phosphate may have shown a faster calcification of the CEP valve, when implanted in sheep, the CEP valve lasted longer. While neither is a very good test vehicle, I would pick the sheep as being a much closer match to a human reality.

Recall that the CEP has an actual track record of 90% still implanted after 18 years - and that was before anticalcification measures were developed. We don't have enough time in on the Mosaic to see how it will do, but the pre-anticalcification Mosaic forerunner did not last as long as the pre-anticalcification Carpentier-Edwards Perimount. I take that as a hint.

The Mosaic Ultra is the Mosaic. They added the Ultra after they tested that they could successfully implant the valve supraannularly, similarly to the CEP Magna, increasing effective annulus size.

Best wishes,

 

[Susan BAV]

Je ne sais quoi...

 

[Andyrdj]

Thanks Bob

Thanks Bob

Good points there.

As I understand it, some of the extra longevity of generation 2 Bovine Pericardial Valves as opposed to porcine valves was due to mechanical durability, ie Porcine valves were more prone to some kind of tearing?

pre-anticalcification Mosaic forerunner did not last as long as the pre-anticalcification Carpentier-Edwards Perimount. I take that as a hint.

That would be the Hancock 2 from Medtronic being compared to the original C/E perimount. Would like to see some studies illustrating this, Bob, I must say my (occasionally lazy) casual glances at longevity studies for these tended to put both in the 80% freedom from explant region for older patients after 15-20 years (can't remember offhand) but the only stats for younger patients I every managed tyo find were for the C/E periomount.

And (to be highly pedantic but in a constructive way....)

While being bathed in Calcium phosphate solution isn't exactly a good simulator when compared to being in a sheep, we're comparing slightly different things here - rate of calcification in an abstract manner in one study versus longevity in another. (though I agree with you that the longevity is the deciding issue in the end). Also perhaps the longevity studies were different valves (one or both?)

Well, food for thought here. I'm cautious not to leap to conclusions after just one study, this sort of thing needs to be repeated in several studies.

But I do wonder what Medtronic have in terms of anticalcification that Edwards haven't matched. And I also wonder how much more rapidly the calcification is occuring (doesn't say in the abstract). Does anyone have a password for a pubmed site?

Finally it would be interesting if we could get representatives from the two companies to comment on this site regarding these tests!

 

[tobagotwo]

If we got two reps from those companies to slug it out in public, no one would buy any tissue valve for years...

There are actually some comparison graphs on the Medtronics website in the Hancock II section that compare the two at 15 years, with much the results you mention.

The cow pericardium is a tougher medium, but has some limitations inthat it must be manufactured into a valve. The Mosaic is already a perfect valve, but porcine tissue has traditionally survived fixation less well than the cow pericardium.

Now that Medtronics uses their zero-g, non-damaging fixation technique on their valves, it will be interesting to see how that enhances the porcine tissue's useful life. As the bovine pericardium was less damaged originally, the Edwards non-damaging fixation process will probably have less overall impact on its valves' lives.

It's still a toss-up between the Medtronics, Edwards, and St. Jude anticalcification treatments. Each has at least one study showing that it's the best. Time will tell.

As far as the testing environment, sheep are used precisely for that purpose. Their chemistry can calcify a valve in a tiny fraction of the time it takes humans to do it, they have valve sizes in our range, and provide an observable in vivo environment. No valve is proof against their calcifying processes.

Best wishes,

 

[oscarsonthepond]

Tobagotwo -

It seems in your writings that you favor Perimount over the Mosaic (although I could be interpreting that completely wrong), yet you have the Mosaic. If you were going to get a new valve today, which would you get? Before I thought it seemed like the Mosaic was, as you described it, the Cadillac....but the more I read about the Perimount it seems like it's really an amazing valve. I remember there was another thread talking about the sharp points of the Perimount piercing the LV, but you noted that that was only in the Mitral position - do you have any idea if that would be something of concern in the aortic (or in my wife's case pulmonary)?