Current Experience with Percutaneous Pulmonary Valve Implantation

First experiences with Myval Transcatheter Heart Valve System in the treatment of severe pulmonary regurgitation in native right ventricular outflow tract and conduit dysfunction

The rate of morbidity and mortality related to pulmonary regurgitation and pulmonary stenosis are big concerns after the surgery for CHD. Percutaneous pulmonary valve implantation has been established as a less invasive technique compared to surgery with promising results according to long-term follow-up of the patients. There are only two approved valve options for percutaneous pulmonary valve implantation until now, which are Melody (Medtronic, Minneapolis, Minn, USA) and Sapien (Edwards Lifesciences, Irvine, Ca, USA). Both valves have limitations and do not cover entire patient population. Therefore, the cardiologists need more options to improve outcomes with fewer complications in a such promising area. Herein, we present a case series applying for pulmonary position in conduits and native right ventricular outflow tract of a new transcatheter valve system Myval ® which is designed for transcatheter aortic valve implantation procedures. This is the first patient series in which the use of Myvalv in dysfunctional right ventricular outflow tracts is described, after surgical repair of CHD.

Percutaneous Pulmonary Valve Implantation: Current Status and Future Perspectives

Patients with congenital heart disease (CHD) with right ventricle outflow tract (RVOT) dysfunction need sequential pulmonary valve replacements throughout their life in the majority of cases. Since their introduction in 2000, the number of percutaneous pulmonary valve implantations (PPVI) has grown and reached over 10,000 procedures worldwide. Overall, PPVI has been proven safe and effective, but some anatomical variations can limit procedural success. This review discusses the current status and future perspectives of the procedure.

Preprocedural Risk Assessment Prior to PPVI with CMR and Cardiac CT

Percutaneous pulmonary valve intervention (PPVI) is a less invasive and less costly approach to pulmonary valve replacement compared with the surgical alternative. Potential complications of PPVI include coronary compression and pulmonary arterial injury/rupture. The purpose of this study was to characterize the morphological risk factors for PPVI complication with cardiac MRI and cardiac CTA. A retrospective review of 88 PPVI procedures was performed. 44 patients had preprocedural cardiac MRIs or CTAs available for review. Multiple morphological variables on cardiac MRI and CTA were compared with known PPVI outcome and used to investigate associations of variables in determining coronary compression or right ventricular-pulmonary arterial conduit injury. The most significant risk factor for coronary artery compression was the proximity of the coronary arteries to the conduit. In all patients with coronary compression during PPVI, the coronary artery touched the conduit on the preprocedural CTA/MRI, whilst in patients without coronary compression the mean distance between the coronary artery and the conduit was 4.9 mm (range of 0.8-20 mm). Multivariable regression analysis demonstrated that exuberant conduit calcification was the most important variable for determining conduit injury. Position of the coronary artery directly contacting the conduit without any intervening fat may predict coronary artery compression during PPVI. Exuberant conduit calcification increases the risk of PPVI-associated conduit injury. Close attention to these factors is recommended prior to intervention in patients with pulmonary valve dysfunction.

Aortic valve repair and replacement in children

ABSTRACT: Several aortic valve (AV) pathologies might necessitate intervention. Percutaneous or surgical AV repair is generally recommended as the initial management strategy in children with AV disease, offering the advantage of stabilization of the heart dimensions and improvement of patients‘ symptoms. When AV repair is not possible or fails, AV replacement is necessary and is associated with several challenges in children. This review will focus on treatment strategy, AV repair techniques, AV replacement choices and outcomes of AV disease management in children.

Aortic valve replacement in children: Options and outcomes

Several disease pathologies such as congenital heart disease and rheumatic fever can affect the aortic valve (AV) in children frequently necessitating intervention. While percutaneous or surgical AV repair is recommended as initial management strategy in children with AV disease, AV replacement (AVR) might become necessary in children with significant valve destruction and after repair or intervention failure. AVR in children is associated with distinct clinical and technical problems owing to several anatomic, social and prosthesis-related issues. In the current review, we list different AV substitutes, discuss their advantages and shortcomings, outline AVR results in children, and explore the divergence of outcomes in various age, anatomy and pathology subgroups; all in the aim to identify optimal AVR choice for each patient taking into consideration his unique anatomic and demographic characteristics.

The Medtronic Melody® transcatheter pulmonary valve implanted at 24-mm diameter--it works

OBJECTIVES

We report the Melody valve implanted and/or expanded to 24-mm diameter.

BACKGROUND

The Medtronic Melody valve has been implanted up to 22 mm in the pulmonary position for over a decade.

METHODS

A retrospective chart review was performed on 82 patients who underwent Melody valve implant. Technical implant method, pre- and postimplant echocardiographic findings, and initial follow-up were reviewed.

RESULTS

Between 04/2008 and 12/2011, 13 Melody valves were successfully implanted in 11 patients, median age 35 years (range 16-61 years), in the pulmonary (bioprosthetic valve, right ventricle to pulmonary artery conduit, native valve) position (n = 9), tricuspid position (bioprosthetic valve n = 3), and aortic position (bioprosthetic valve n = 1). Ten valves were delivered on a 24-mm balloon in balloon catheter and three were implanted using a 22-mm Ensemble balloon delivery system, followed by postdilation using a 24-mm × 2-cm Atlas balloon catheter. Postimplant, the median peak systolic gradient across the pulmonary valve was 7 mm Hg and median gradient across the tricuspid valve was 3 mm Hg. There was no change in gradient across the Melody valve in the aortic position where valve prosthesis-patient mismatch was present. Postimplant intracardiac echocardiography demonstrated none or mild valve regurgitation. No more than mild regurgitation was noted at a median follow-up of 9.5 months.

CONCLUSIONS

The Melody valve can be implanted at 24 mm in the stenotic/regurgitant bioprosthetic pulmonary, tricuspid, and aortic valve, dysfunctional right ventricle to pulmonary artery conduit, and the native right ventricular outflow tract, whereas the valve remains competent with only mild regurgitation.

Results of balloon dilatation of stenotic homografts in pulmonary position in children and young adults

OBJECTIVES

To evaluate the results of balloon dilatation of stenotic homografts in children, adolescents, and young adults and to identify factors that might influence or predict the effect of the dilatation.

BACKGROUND

Homografts are widely used in congenital cardiac surgery; however, the longevity remains a problem mostly because of stenosis in the homograft. The effect of treatment by balloon dilatation is unclear.

METHODS

In a retrospective study, the effect of balloon dilatation was determined by the percentage of reduction of the peak systolic pressure gradient over the homograft during catheterisation and the postponement of re-intervention or replacement of the homograft in months. Successful dilatations - defined in this study as a reduction of more than 33% and postponement of more than 18 months - were compared with unsuccessful dilatations in search of factors influencing or predicting the results.

RESULTS

The mean reduction of the peak systolic pressure gradient was 30% in 40 procedures. Re-intervention or replacement of the homograft was postponed by a mean of 19 months. In all, 14 balloon dilatations (35%) were successful; the mean reduction was 49% and the mean postponement was 34 months. The time since homograft implantation, the presence of calcification, the homograft/balloon ratio, and the pressure applied during dilatation all tended to correlate with outcome, but were not statistically significant.

CONCLUSIONS

Balloon dilatation is able to reduce the peak systolic pressure gradient over homografts in a subgroup of patients and can be of clinical significance to postpone re-intervention or pulmonary valve replacement.

Eighteen-month outcome of pulmonary valve stent implantation by direct right ventricle puncture: an animal study

OBJECTIVE

The purpose of this study was to investigate the feasibility and safety of pulmonary valve implantation via direct right ventricle puncture.

METHODS

A standard thoracotomy and direct right ventricle puncture were performed in 8 healthy sheep to implant the pulmonary valve stents. Animals were followed up for 18 months.

RESULTS

Three sheep died within the first 4 months after stent placement. The remaining 5 animals survived. After 18 months, examinations by color echocardiography, 64-slice computed tomography scan, and cardiac catheter showed an ideal position of each stent. The function of the pulmonary valves and hearts was not different compared with the preoperative conditions of the sheep. Anatomic examination revealed that the stent was covered by a layer of endothelial tissue with no stent fracture or valvular calcification. The histologic evaluation of the stent and surrounding tissue showed that the surface of the stent was smooth and covered by a complete layer of endothelial cells without obvious infiltration of inflammatory cells. The vascular wall was integrative without tear phenomenon in each layer of tissue.

CONCLUSIONS

These results show that pulmonary valve stents can be implanted via direct right ventricle puncture. Further studies evaluating xenograft valve material and the effect of implantation in vivo are needed.

Precise Stent Placement Using the New Siemens Artis Zeego 3D Rotation Angiography in a Stenosis of a Shelhigh Pulmonary Conduit

Stenting of the Shelhigh pulmonary conduit was performed 2 years after a Ross procedure because of a stenosis of the distal segment. We used the new Siemens Artis Zeego technology. A precise placement of the stent to release the stenosis within the distal segment simultaneously retaining a competent valve was possible by using the Dyna-computed tomography technology. The early onset of a stenosis of the Shelhigh xenograft in the pulmonary position is alarming, thus, its use can not be recommended for a replacement of the pulmonary valve.

Percutaneous reimplantation of a pulmonary valved stent in sheep: a potential treatment for bioprosthetic valve degeneration

OBJECTIVE

Percutaneous pulmonary valve replacement has been recently introduced into clinical practice. Patients with transcatheter pulmonary valve replacement will definitely face the problems of valve degeneration. In addition to surgical re-replacement of the degenerated bioprosthetic valves, we studied the replacement of degenerated bioprosthetic valves with transcatheter reimplantation of stent-mounted pulmonary valves.

METHODS

Percutaneous pulmonary valve replacement was first performed in 6 sheep used a homemade valved stent. Two months after the initial procedure, the 6 sheep previously implanted with a valved stent underwent the same implantation procedure of a pulmonary valved stent. Hemodynamic assessment of the bioprosthetic pulmonary valve was obtained by echocardiography immediately post-implant and at 2 months follow-up.

RESULTS

All 6 sheep had successful transcatheter stent-mounted pulmonary valve replacement in the first experiment. After 2 months, reimplantation was successful in 5 sheep but failed in 1 sheep because the first valved stent was pushed to the bifurcation of the pulmonary artery by the delivery sheath. Echocardiography confirmed the stents were in the desired position during the follow-up. The remaining 5 sheep with normal valvular and cardiac functionality survived for 3 months after implantation.

CONCLUSION

Transcatheter stent-mounted bioprosthetic pulmonary valve reimplantation is feasible in an animal model and more convenient than open chest reimplantation.

Transcatheter and transapical aortic valve replacement

Minimally invasive valve replacement is limited to bioprosthetic aortic and pulmonary valves for use in very specific populations of patients. Replacement via trans-catheter and transapical techniques should be used only in patients in whom traditional surgical replacement is deemed an unacceptable risk. Nursing management will focus heavily on care for comorbid conditions because of the high-risk nature of the patients in whom these valves will initially be implanted.