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We would like to compliment Ferrari and associates on their recent
study . They convincingly prove the need for a less invasive technique
of aortic valve replacement, firstly, due to the increasing number of
older patients requiring aortic valve replacement and, secondly, due to
the high one-month mortality rate among nonagenarians after open heart
The authors evaluated the feas...
The authors evaluated the feasibility of percutaneous aortic valve
replacement with a self-expanding nitinol stent in beating pig hearts. The
implanting procedure could be successfully performed in four of six
animals via the left subclavian artery with an implantation catheter of 25
French. For the first time, this technology was tested in their
experimental model under haemodynamic stress conditions.
Besides these haemodynamic stress tests, the fact that the valved
stents could be deployed intra-annular without obstructing the coronary
orifices deserves merit. Our group’s experience demonstrated that it is
very difficult to position a valved stent into porcine aortic anuli
without occlusion of the coronary ostia by native leaflets when pushed
against the aortic wall. We reported on endovascular aortic valve
implantation to the descending and ascending aorta using self-expanding
nitinol stents in 2002. In eleven of 14 pigs, valved stents were
successfully implanted via an iliac or infra-renal approach (descending,
n=6, supracoronary, n=3, subcoronary, n=2) and demonstrated low
transvalvular gradients with good angio- and echocardiographic results. An
implantation device of 22 French had been used .
Unfortunately, our study has been inadvertently cited in the wrong
context because it was the first-ever use of a self-expaning valved stent,
not a balloon expandable. Therefore, the author’s statement that “all
approaches to percutaneous valve replacement to date have used a balloon
expandable stent” is not quite correct.
The haemodynamic conditions during percutaneous valve implantation
are very crucial. Ferrari and co-workers could not reveal “any relevant
drop in blood pressure” in their healthy pigs. We would like to emphasize
that even minor disturbances of the haemodynamics can lead to fatal
complications in patients with end-stage aortic valve stenosis and
cardiomyopathy. Therefore, heamodynamic parameters should be meticulously
registered during valved stent deployment in future studies and the data
should be presented in detail. These data are important to evaluate the
necessity of circulatory support, e.g. a femoro-femoral bypass, during
Another key concern in progressing from the experimental model to
clinical applicability is mentioned by Doctor Ferrari and colleagues:
calcification. They speculate that a stent may obstruct the left
ventricular outflow tract in heavily calcified aortic stenosis, and
suggest a preceding balloon valvoplasty in these patients before
implantation of a self-expanding stent valve. We agree with the authors
that calcification is the major obstacle to implanting a self-expanding
valved stent in the aortic position. Not only because the expansion force
of the stent is not great enough to dilate the stenotic valve structures
resulting in an insufficient valve area, but also because of the well
known dilemmas, not mentioned by the authors: embolic complications,
impairment of coronary flow, paravalvular leakage, haemorrhaging, and
smaller aortic valve area compared to after a surgical procedure.
We would like to offer an alternate procedure, on which we are
already working, for the solution of these problems: percutaneous aortic
valve resection. In a preliminary study, the use and feasibility of a high
-pressure water jet system as a new promising surgical method for the
endovascular ablation of human calcified aortic valves has been
successfully performed and evaluated . Nevertheless, the realization of
an ideal endoluminal aortic valve replacement process is challenging, and
only sophisticated technical refinements of the tools will lead to success
The Jena-group’s article advances the transarterial aortic valve
replacement procedure. At the same time, this study shows clearly the
multiple limitations that are still present in this evolving field. Only
two thirds of the implantations were successful in the Jena-study.
Problems with the implantation device and the correct positioning
occurred. Therefore, their and also our study indicate the necessity for
further improvements of the: visualization method, resection tool (for
prior percutaneous valve resection), application device, guidance of
catheters and their miniaturisation [3,4].
Certainly, open heart surgery is still and will remain the golden
standard in aortic valve replacement for many years to come.
(1). Ferrari M, Figulla HR, Schlosser M, Tenner I, Frerichs I, Damm C,
Guyenot V, Werner GS, Hellige G. Transarterial aortic valve replacement
with a self-expanding stent in pigs. Heart. 2004;90:1326-31.
(2). Lutter G, Kuklinski D, Berg G, von Samson P, Martin J, Handke M,
Uhrmeister P, Beyersdorf F. Percutaneous aortic valve replacement: an
experimental study. I. Studies on implantation. J Thorac Cardiovasc Surg.
(3). Lutter G, Ardehali R, Cremer J, Bonhoeffer P. Percutaneous valve
replacement: current state and future prospects. Ann Thorac Surg.
(4). Quaden R, Attmann T, Puehler T, Boening A, Hagemann A, Cremer J,
Lutter G. Percutaneous aortic valve replacement: studies on ablation. 3rd
EACTS/ESTS Joint Meeting, September 12-15, 2004, Leipzig, Germany.
Jump to comment:
We would like to compliment Ferrari and associates on their recent study . They convincingly prove the need for a less invasive technique of aortic valve replacement, firstly, due to the increasing number of older patients requiring aortic valve replacement and, secondly, due to the high one-month mortality rate among nonagenarians after open heart surgery.
The authors evaluated the feas...