|
|
||||||||
Eur J Cardiothorac Surg 2003;24:212-216
© 2003 Elsevier Science NL
a Cardiothoracic Department, The No. 1 People's Hospital of Shaoxing, Zhejiang, China
b Department of Cardiovascular Surgery, Centre Hospitalier Universitaire Vaudois (CHUV), 46 Rue du Bugnon, CH-1011 Lausanne, Switzerland
Received 27 January 2003; received in revised form 12 March 2003; accepted 17 March 2003.
* Corresponding author. Tel.: +41-21-314-2280; fax: +41-21-314-2278
e-mail: antonio.corno{at}chuv.hospvd.ch
| Abstract |
|---|
|
|
|---|
Key Words: Biological valved conduits Pulmonary valve implantation Pulmonary valve regurgitation Tetralogy of Fallot
| 1. Introduction |
|---|
|
|
|---|
Insertion of a valve in pulmonary position is indicated mainly in two situations: (a) pulmonary valve regurgitation, generally after surgical repair for tetralogy of Fallot [614]; and (b) dysfunction of the biological valved conduit previously implanted to establish the continuity between the right ventricle and the pulmonary artery during repair of complex congenital heart defects [15,16].
So far the conventional treatment for the above situations consisted in pulmonary valve replacement [614] and replacement of the biological valved conduit [1517], even if with uncertainty about the adequate timing for pulmonary valve insertion in order to prevent or reduce the incidence of sudden death, arrhythmias and right ventricular dysfunction [514].
Several alternative strategies, particularly in the presence of a dysfunction of a biological valved conduit, have been considered within the last years, including other types of biological valved conduits [1820] or endovascular stent implantation to dilate and delay the surgical replacement of the obstructed conduit [2123].
The main limit in the use of endovascular stents to dilate an obstructed biological conduit implanted between the right ventricle and the pulmonary artery is that, even if the obstruction is relieved or substantially reduced without requiring for a re-operation on cardiopulmonary bypass, the patient remains with a pulmonary valve regurgitation, frequently worse than before. The subsequent right ventricular volume overload can cause irreversible myocardial damages, with the known incidence of sudden death, arrhythmias and right ventricular dysfunction [514,24].
The advantages of the percutaneous insertion of the pulmonary valve over the conventional surgical techniques are quite evident in terms of avoiding an operation on cardiopulmonary bypass, and in the same time in the ability of implanting a functioning valve, therefore reducing or abolishing both the pressure and the volume overload on the right ventricle [1,4,5]. The major limit of this recently reported technique is the mismatch between size of the venous access and size of the introducer (at least 18 Fr), restricting the use of this strategy to older children and the size of the valve to an 18 mm internal diameter biological valve [5].
Because of the above problems, we devised an experimental study to evaluate an alternative strategy aiming at the off-bypass implantation of a self-expandable valved stent of large size in pulmonary position from right ventricular approach.
| 2. Materials and methods |
|---|
|
|
|---|
Acute in vivo evaluation was performed in six adult pigs, mean body weight 55.6 kg (range 4767 kg). After general anaesthesia, tracheal intubation and mechanical ventilation, with continuous monitoring of electrocardiogram, arterial and central venous pressure and oxygen saturation, the chest was opened through a conventional median sternotomy. Heparin was administered i.v. (1 mg/kg). After a short incision (4 mm) on the anterior aspect of the right ventricle, controlled by a purse string on 4-0 polypropylene suture, through the sheath stent-graft delivery system the valved stent was implanted off-bypass in pulmonary valve position by trans-ventricular approach (Fig. 1) . The correct positioning of the valved stent was evaluated and confirmed before definitive deployment by intravascular ultrasound technique.
|
A high fidelity tip mounted Millar pressure transducer system was used to invasively measure the pressure proximal and distal to the valve.
At the end of the study the animals were electively sacrificed to check the adequate position of the valved stent, as well as its deployment and anchorage and the presence of any deformation of the valve.
All animals received human care in compliance with the Principles of Laboratory Animals formulated by the National Society of Medical Research and the Guide for the Care and Use of Laboratory Animals prepared by the Institute of Laboratory Animal Resources and published by the National Institutes of Health (NIH publication 85-23, revised 1985). The protocol was approved by the institutional Committee on Animal Research.
Statistical analysis: the Student's t-test was utilized, and all data were expressed as mean±standard deviation.
| 3. Results |
|---|
|
|
|---|
The mean peak pressure gradient recorded across the valve was 6.33±2.8 mmHg (range 4.59.6 mmHg) at Doppler echocardiography, and 4.5±3.1 mm Hg (range 07 mmHg) at invasive measurement, with a mean pulmonary blood flow of 3.03±0.05 l/min.
Intravascular ultrasound showed complete opening and closure of the valve (mean area reduction from 315.08±54.13 to 0 mm2) (Fig. 2) . In all animals Doppler echocardiography confirmed the absence of any valve regurgitation as well as of paravalvular leak (Fig. 3) .
|
|
Post-mortem examination confirmed the adequate position of the valved stent in pulmonary position (Fig. 4) , as well as ruled out any valve deformation or thrombus (Fig. 5) .
|
|
| 4. Discussion |
|---|
|
|
|---|
Because of the difficult balance between costs (risks) and benefits (competent pulmonary valve), timing and type of management so far have not reach general agreement [24].
The percutaneous insertion of a pulmonary valve, recently introduced in the clinical practice [4,5], presents the advantages of avoiding an operation on cardiopulmonary bypass and in the same time the possibility of implanting a functioning valve, therefore reducing or abolishing both the pressure and the volume overload on the right ventricle [1,4,5]. The major current limit of this technique is the mismatch between size of the venous access and size of the introducer (at least 18 Fr), restricting the use to older children (>25 kg of body weight) and the size of the valve to an 18 mm internal diameter biological valve [5].
Our experimental study proposes an alternative strategy allowing the off-bypass implantation of a self-expandable valved stent of large size (internal diameter=22 mm) in pulmonary position from right ventricular approach without cardiopulmonary bypass.
The implant of a functioning pulmonary valve can therefore been accomplished, overcoming the limits of the currently available techniques, with the only additional risks of a limited chest opening. In our initial experimental study we used a median sternotomy because we wanted to evaluated the feasibility of the new technique. In fact, based on this first experience, the implant of the valved stent in pulmonary position can be accomplished through a limited left anterior thoracotomy, particularly advantageous in clinical practice in the presence of a previous median sternotomy.
With regard to the size of the valved stent, the mean external diameter of 26.3±0.7 mm should allow adequate implant even in patients with dilated right ventricular outflow tract because of severe pulmonary valve regurgitation, like the situation encountered years after repair of tetralogy of Fallot with transannular patch.
With regard to the larger size of available biological valve, the internal diameter of 22 mm, because of the favourable effective orifice area, allows an adequate hemodynamics without pressure gradient in patients up to 91 kg of body weight, as we already reported [26].
Of course our positive preliminary experimental data will need to be validated by chronic studies.
4.1. Conclusions
(a) The off-bypass implantation of self-expandable valved stent is feasible in pulmonary position; (b) the off-bypass surgical approach allows for valved stent implantation of adult size with adequate hemodynamic functioning; and (c) intravascular ultrasound makes implantation and evaluation easy and reproducible.
| Acknowledgments |
|---|
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
C. H. Huber, B. Marty, and L. K. von Segesser Acceptance and introduction of disruptive technologies simple steps to build a fully functional pulmonary valved stent Interactive CardioVascular and Thoracic Surgery, August 1, 2007; 6(4): 430 - 432. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. Antunes Off-pump aortic valve replacement with catheter-mounted valved stents.: Is the future already here? Eur. J. Cardiothorac. Surg., January 1, 2007; 31(1): 1 - 3. [Full Text] [PDF] |
||||
![]() |
T. Walther and F. W. Mohr Aortic valve surgery: time to be open-minded and to rethink Eur. J. Cardiothorac. Surg., January 1, 2007; 31(1): 4 - 6. [Full Text] [PDF] |
||||
![]() |
P. Tozzi, M. Pawelec-Wojtalic, D. Bukowska, V. Argitis, and L. K. von Segesser Endoscopic off-pump aortic valve replacement: does the pericardial cuff improve the sutureless closure of left ventricular access? Eur. J. Cardiothorac. Surg., January 1, 2007; 31(1): 22 - 25. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Schreiber, J. Horer, M. Vogt, S. Fratz, M. Kunze, C. Galm, A. Eicken, and R. Lange A new treatment option for pulmonary valvar insufficiency: first experiences with implantation of a self-expanding stented valve without use of cardiopulmonary bypass Eur. J. Cardiothorac. Surg., January 1, 2007; 31(1): 26 - 30. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Attmann, R. Quaden, T. Jahnke, S. Muller-Hulsbeck, A. Boening, J. Cremer, and G. Lutter Percutaneous Pulmonary Valve Replacement: 3-Month Evaluation of Self-Expanding Valved Stents Ann. Thorac. Surg., August 1, 2006; 82(2): 708 - 713. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K. von Segesser Closure devices: the solution for repair of direct access apertures after valved stent implantation? Eur. J. Cardiothorac. Surg., July 1, 2006; 30(1): 2 - 3. [Full Text] [PDF] |
||||
![]() |
C. H. Huber and L. K. von Segesser Direct Access Valve Replacement (DAVR) -- are we entering a new era in cardiac surgery? Eur. J. Cardiothorac. Surg., March 1, 2006; 29(3): 380 - 385. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Attmann, T. Jahnke, R. Quaden, A. Boening, S. Muller-Hulsbeck, J. Cremer, and G. Lutter Advances in Experimental Percutaneous Pulmonary Valve Replacement Ann. Thorac. Surg., September 1, 2005; 80(3): 969 - 975. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Ma, P. Tozzi, C. H. Huber, S. Taub, G. Gerelle, and L. K. von Segesser Double-crowned valved stents for off-pump mitral valve replacement Eur. J. Cardiothorac. Surg., August 1, 2005; 28(2): 194 - 198. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Mohammadi, E. Belli, I. Martinovic, L. Houyel, A. Capderou, J. Petit, C. Planche, and A. Serraf Surgery for right ventricle to pulmonary artery conduit obstruction: risk factors for further reoperation Eur. J. Cardiothorac. Surg., August 1, 2005; 28(2): 217 - 222. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. H. Huber, L. H. Cohn, and L. K. von Segesser Direct-Access Valve Replacement: A Novel Approach for Off-Pump Valve Implantation Using Valved Stents J. Am. Coll. Cardiol., July 19, 2005; 46(2): 366 - 370. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Yin, J. Salazar, L. Nolke, A. Azakie, and T. R Karl Late Pulmonary Valve Implantation after Repair of Tetralogy of Fallot Asian Cardiovasc Thorac Ann, June 1, 2005; 13(2): 139 - 142. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Quaden, T. Attmann, A. Boening, J. Cremer, and G. Lutter Percutaneous aortic valve replacement: resection before implantation Eur. J. Cardiothorac. Surg., May 1, 2005; 27(5): 836 - 840. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Pawelec-Wojtalik, L. K. von Segesser, M. Liang, and D. Bukowska Closure of left ventricle perforation with the use of muscular VSD occluder Eur. J. Cardiothorac. Surg., April 1, 2005; 27(4): 714 - 716. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K. von Segesser, B. Marty, P. Tozzi, and P. Ruchat Impact of endoluminal stenting for aortic surgery Eur. J. Cardiothorac. Surg., December 1, 2004; 26(Suppl_1): S14 - S18. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K. von Segesser Direct percutaneous valve replacement: the next step? Eur. J. Cardiothorac. Surg., November 1, 2004; 26(5): 873 - 874. [Full Text] [PDF] |
||||
![]() |
A. F. Corno, S. D. Qanadli, N. Sekarski, S. Artemisia, M. Hurni, P. Tozzi, and L. K. von Segesser Bovine Valved Xenograft in Pulmonary Position: Medium-Term Follow-Up With Excellent Hemodynamics and Freedom From Calcification Ann. Thorac. Surg., October 1, 2004; 78(4): 1382 - 1388. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. H. Huber, P. Tozzi, A. F. Corno, B. Marty, P. Ruchat, P. Gersbach, M. Nasratulla, and L. K. von Segesser Do valved stents compromise coronary flow? Eur. J. Cardiothorac. Surg., May 1, 2004; 25(5): 754 - 759. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |