Percutaneous Pulmonary Valve Replacement Research Articles

Abstract 2347: Pulmonary Regurgitation: The Impact on Right Ventricle and the Effect of Percutaneous Pulmonary Valve Replacement

Background Despite successful repair of tetralogy of Fallot (TOF), the life expectancy for these patients remains lower than in the general population. This is mainly due to free pulmonary regurgitation (PR). The importance of maintaining a competent valve has been emphasized, but the optimal timing for intervention remains to be established. The purposes of this study were in a pig model to investigate the consequences of the duration of free PR on RV, and the reversibility of these changes after percutaneous pulmonary valve replacement. Methods Thirtysix farm pigs were divided into four groups (A, B, C and D) of nine pigs. At baseline group A, B and C had a percutaneous stent inserted into the pulmonary annulus to create free PR. After 4, 8 and 12 weeks, respectively, group A, B and C underwent percutaneous valve replacement. In order to allow remodelling of RV, the pigs were observed for four weeks after valve insertion before euthanasia. To examine RV function, MRI was performed before stent insertion, before valve replacement, and before euthanasia. Group D served as controls and underwent five MRI examinations: at baseline as well as after four, eight, twelve and sixteen weeks. Results When comparing the group D with group A, B & C, RVEDV and RVESV were found to gradually increase over time. Furthermore, these volumes normalised after valve replacement in group A and B, but remains increased in the group C. Similar, RVEF was normal after valve replacement in group A and B, but impaired in the group the long-term free PR compared to the controls. Conclusion Better timing of valve replacement in patients with free PR after TOF repair is of outermost clinical relevance. This study examined the impact of free PR on RV in a pig model. Despite the relative short duration of the volume overload, the RV underwent irreversible changes. This may be explained by the fact that, in contrast to TOF, the RV is not hypertrophic. The study showed that RV tolerates volume overload from free PR for a certain time, but too late intervention will cause irreversible deterioration of the ventricular function. Thus, the model may serve to identify predictors, e.g. tissue-Doppler measurements or natriuretic peptides, for RV function after valve replacement and thereby optimise timing of intervention.

Anaesthesia for percutaneous pulmonary valve replacement in adults: report of 3 cases

Anaesthesia for percutaneous pulmonary valve replacement in adults: report of 3 cases

Percutaneous Pulmonary Valve Replacement: 3-Month Evaluation of Self-Expanding Valved Stents

In a recent study our group established an acute animal model of percutaneous pulmonary valve replacement using self-expanding nitinol stents. The present study was performed to evaluate these valved stents over a 3-month period. Bovine jugular xenografts were sutured into nitinol stents. Transfemoral implantation in the pulmonary position using a modified commercially available application device (with a 22-French outer diameter) was evaluated in 9 sheep. Two sheep died shortly after successful valved stent implantation due to internal venous hemorrhage. Another 1 sheep died 2.5 months after the procedure due to vegetations on the neovalve leading to subtotal stenosis. All other animals survived the 3-month study time (n = 6). An orthotopic pulmonary valved stent position was achieved in 4 animals and a supravalvular position in 1. During the deployment procedure, rhythm disturbances occurred in all animals, and mean arterial blood pressure dropped from 83.9 +/- 26.0 mm Hg to 68.3 +/- 22.3 mm Hg (p = 0.006) (n = 5). The peak-to-peak transvalvular gradient was 5.1 +/- 4.0 mm Hg initially (n = 5), and 3.6 +/- 1.6 mm Hg at follow-up (n = 5). Three-month angiographic and echocardiographic follow-up confirmed competent neovalves without paravalvular leakages. After 3 months of implantation, percutaneously implanted memory nitinol valved stents demonstrated good function in the sheep.

Invited commentary

The article by Attmann and coworkers [1] presents the results of a chronic animal feasibility study of using a self-expanding nitinol stent supporting a bovine jugular vein valve for percutaneous pulmonary valve replacement, and represents continuing work previously reported by the same group [2]. In this experiment, 9 sheep received the nitinol stented bovine valve percutaneously with 2 animals experiencing lethal bleeding complications attributed to the procedure and 1 animal succumbing to endocarditis at 2.5 months.

Optimal Management Strategies for Patients With Complex Congenital Heart Disease

The combination of critical pulmonary outflow obstruction with a large ventricular septal defect is symbolized by the diagnosis of tetralogy of Fallot, the most common form of cyanotic congenital heart disease. In many ways, the history of management for patients with tetralogy is representative of the evolution of management for all children with complex congenital cardiac diagnoses. Tetralogy was the first complex lesion addressed surgically with the palliative Blalock-Taussig shunt in 1945 and the first repaired completely with patients’ mothers serving as the bypass machine in 1954.1,2 The introduction of valved conduits in 1964 allowed repair of lesions not previously considered amenable to correction.3 The next 3 decades were marked by improved survival at open heart repair, recognition of the progressive deterioration of valved conduits necessitating early and repeated reoperation, and a progressive decrease in the age of primary repair to now the first few months of life.4,5 In the late 1970s, reports of arrhythmia and late sudden death among tetralogy survivors led to evaluation of tetralogy cohorts with residual right ventricular (RV) volume and/or pressure overload identified as predictors of late complications.6,7 Recognition of this problem heightened appreciation of the importance of arrhythmias in postoperative congenital heart disease patients and identified the need for informed long-term care and attention to residua of earlier procedures for all patients with congenital heart disease.8 Finally, the last 20 years have witnessed the dramatic rise in interventional procedures to address both correction of simple lesions and palliation/management of complex diagnoses.9 Article p 2598 The remarkable progress in care of children with tetralogy exemplifies the collaboration between pediatric cardiologists and congenital cardiac surgeons, the development of new techniques to address problems as they emerge, and the continuous evolution of management that have characterized care of all patients with …

Percutaneous replacement of pulmonary valve using the Edwards‐Cribier percutaneous heart valve: First report in a human patient

We report on the use of the Edwards-Cribier percutaneous heart valve (PHV) in a stenotic right ventricle to pulmonary artery homograft in a 16-year old patient who underwent the Ross operation. Initially, the homograft was stented and at the same procedure, the PHV was deployed inside it. This is the first human case of the application of this valve in the pulmonary valve position.

Percutaneous pulmonary valve replacement: Long-term evaluation of valved nitinol stents

Percutaneous pulmonary valve replacement: Long-term evaluation of valved nitinol stents

Off-pump replacement of the pulmonary valve in large right ventricular outflow tracts: A hybrid approach

Percutaneous pulmonary valve replacement has recently been introduced and is under investigation in humans. This technique is, however, limited to patients with a right ventricular outflow tract that does not exceed 22 mm in diameter. We report our experience of off-pump pulmonary valve replacement using a hybrid approach in animals with large right ventricular outflow tracts. Eight ewes were included in the protocol and were equally divided into 2 groups. A left thoracotomy was first performed, and the main pulmonary artery was banded by using 2 radiopaque rings with a diameter of 18 mm that allowed for further pulmonary valve replacement. We then intended to implant a valved stent either percutaneously (group 1) or through a transventricular approach (group 2). All animals were killed after valve implantation. The operation allowed the pulmonary diameter to be reduced from 30 to 17.6 mm. The right ventricular pressure did not significantly increase after reduction of the pulmonary artery diameter (25 vs 36 mm Hg). Subsequent pulmonary valve replacement through a percutaneous or a transventricular approach was always possible without any requirement for extracorporeal circulation. All devices were successfully delivered inside the pulmonary artery banding and were functioning perfectly at early evaluation. Implantation of a pulmonary valve is possible in ewes through a hybrid approach when the right ventricular outflow tract exceeds 22 mm in diameter. This involves both surgeons and interventionists and allows for a staged procedure in which the valvulation is performed percutaneously or, for a combined hybrid approach, in which the valve is implanted off pump transventricularly during the same operation.

Percutaneous pulmonary valve replacement in a large right ventricular outflow tract: An experimental study

ObjectivesWe report our initial experience with percutaneous pulmonary valve replacement in animals with large pulmonary trunks, using a modified percutaneous approach. BackgroundPercutaneous pulmonary valve replacement has recently been introduced, and early clinical experience has been reported. This technique is presently limited to patients with a right ventricular outflow tract no bigger than 22 mm in diameter. MethodsIn seven animals (groups 1 and 3), we implanted a newly designed nitinol stent in the shape of a conduit with a central restriction of its diameter, containing an 18-mm bovine valve, as a one-step procedure. The animals in groups 1 and 3 were sacrificed after valve implantation and after two-month follow-up, respectively. In the second group (n = 3), we expected to percutaneously reduce the diameter of the pulmonary artery. Eight weeks later, we implanted an 18-mm valve mounted in a balloon-expandable stent. These animals were sacrificed after valve implantation. ResultsEight of 10 devices were successfully delivered and were functioning perfectly at the initial evaluation and after two months. We failed to cross the tricuspid valve in two cases. The downsize mechanism allowed the pulmonary diameter to be reduced from 30 to 18 mm, without an impact on right ventricular function in any of the animals. ConclusionsNon-surgical implantation of a pulmonary valve is possible in ewes with all types of pulmonary trunk, regardless of its size. A “downsize” stent is needed to allow valve implantation in a large trunk. Further refinements will make this technique feasible in humans.

Steps toward percutaneous aortic valve replacement.

To date, the surgical approach is the only option to replace the aortic valve. Percutaneous pulmonary valve replacement has recently opened new perspectives on transcatheter replacement of cardiac valves. We report our experience of aortic valve replacement through a percutaneous technique in lambs. A bovine jugular vein containing a valve was dissected and sutured into a stent. Twelve lambs were divided into 3 groups. In the first, a valved stent was implanted in the descending aorta after creation of an aortic insufficiency. In the second, the valve was implanted in the native position. In the third, we inserted a valved stent in the native position using an orientation mechanism. All valves were successfully delivered and functioned perfectly in short-term evaluation. All experiments in group 2 failed: 1 valve obstructed the coronary artery orifices, 1 stent was responsible for a major mitral valve insufficiency, and the third implant migrated prematurely. A paraprosthetic leak occurred in the last animal in this group. Animals in group 3 had successful implantation of the valved stent. The orientation mechanism allowed perfect alignment of the device without any damage to the coronary circulation or to mitral valve function. Nonsurgical implantation of an aortic valve is possible in lambs in the descending aorta and in the native position. An orientation mechanism is obviously needed to avoid obstruction of the coronary orifices. With further improvements, this technique should be feasible in humans.

The percutaneous implantable heart valve

Recently, percutaneous valve implantation has become an alternative technique to surgical valve replacement enlarging the field of interventional catheterization. Our animal experimentation has shown the technical feasibility of pulmonary valve replacement. This led to the first human implants in the year 2000. After demonstration of the feasibility in the human with five successful implantations, two major questions are open. Will we become more aggressive in pulmonary valve replacement due to a less traumatic approach? Second, will percutaneous valve replacement also become available for other cardiac valves? In this manuscript, we describe the state of the art percutaneous pulmonary valve replacement in humans. Furthermore, we give insight into our research placing the prosthetic valve in the aortic position.

Percutaneous replacement of pulmonary valve in a right-ventricle to pulmonary-artery prosthetic conduit with valve dysfunction

Valved conduits from the right ventricle to the pulmonary artery are frequently used in paediatric cardiac surgery. However, stenosis and insufficiency of the conduit usually occur in the follow-up and lead to reoperations. Conduit stenting can delay surgical replacement, but it aggravates pulmonary insufficiency. We developed an innovative system for percutaneous stent implantation combined with valve replacement. A 12-year-old boy with stenosis and insufficiency of a prosthetic conduit from the right ventricle to the pulmonary artery underwent percutaneous implantation of a bovine jugular valve in the conduit. Angiography, haemodynamic assessment, and echocardiography after the procedure showed no insufficiency of the implanted valve, and partial relief of the conduit stenosis. There were no complications after 1 month of follow-up, and the patient is presently in good physical condition. We have shown that percutaneous valve replacement in the pulmonary position is possible. With further technical improvements, this new technique might also be used for valve replacement in other cardiac and non-cardiac positions.

Transcatheter implantation of a bovine valve in pulmonary position: a lamb study.

Pulmonary regurgitation can lead to severe right ventricular dysfunction, which is a delicate postoperative problem in the long-term follow-up of patients who had surgery for congenital heart diseases. Clinical conditions of patients suffering from pulmonary valve incompetence are improved by valve replacement with a prosthetic valve. To date, the surgical approach is the only option to replace a pulmonary valve. We report the first experience of percutaneous pulmonary valve implantation. A fresh bovine jugular vein containing a native valve was sutured into a vascular stent and then cross-linked with a 0.6% glutaraldehyde solution for 36 hours. After being hand-crimped onto a balloon catheter, the device was inserted percutaneously according to standard stent-placing techniques. The valved stent was finally deployed in the position of the native pulmonary valve of the lamb. Hemodynamic evaluation was carried out before and 2 months after implantation. Anatomic evaluation was finally performed. Percutaneous pulmonary valve replacement was successful in 5 lambs. No complications were noted. Early and late angiographic and hemodynamic studies confirmed a good position of the stents with a competent valve at the end of the protocol. One stent was slightly stenotic, with macroscopically visible calcifications. Nonsurgical implantation of pulmonary valves is possible in the lamb. This new technique is similar to standard stent implantation. Thus, it should be feasible in humans, in whom it will lead to a significant reduction of reoperations in patients in need of pulmonary valve replacement.