Transcatheter Aortic Valve Replacement

Percutaneous Transcatheter Valve-in-Valve Implantation With the Balloon-Expandable Valve for the Treatment of a Dysfunctional Tricuspid Bioprosthetic Valve — A Pediatric Case Report

Baher Matta Hanna, MD, Josep Rodés-Cabau, MD, Nagib Dahdah, MD

Baher Matta Hanna, MD, Josep Rodés-Cabau, MD, Nagib Dahdah, MD

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Abstract: An inverted Edwards SAPIEN 23 mm valve was implanted in a 14-year-old patient with Ebstein’s anomaly who received a Medtronic Mosaic 25 mm valve 8 years earlier and presented with significant progressive symptoms related to severe valvular regurgitation and moderate stenosis. The procedure was performed via the femoral vein using the RetroFlex 3 system and predilatation of the tricuspid valve, under transesophageal echocardiographic guidance. The patient had an immediate drop in right atrial and trans-tricuspid pressures with mild regurgitation, and had stable results on short-term follow-up.

J INVASIVE CARDIOL 2013;25(6):310-312

Key words: transcatheter, intervention, tricuspid, bioprothesis, revalvulation

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Options offered for tricuspid valve lesions not amenable to medical treatment are suboptimal, since they carry inherent risks of morbidity and mortality in both the short and long terms.1-4 Bioprosthetics have been preferred to mechanical valves because of lower failure and complication rates, and no necessity for anticoagulation. However, the need for re-operation is elevated because of valve degeneration.5,6 In the pediatric age group, somatic growth is an additional factor leading to progressive prosthetic undersize. Since the introduction of percutaneous valve implantation in 2000,7 the technique has expanded from the pulmonary valve then right ventricle to pulmonary artery conduit, to the aortic position,8 and then very recently to the atrioventricular positions.9-17

Case Description

A 14-year-old boy was diagnosed since early life with Ebstein’s anomaly causing severe tricuspid regurgitation. He received a surgical replacement of the tricuspid valve when 6 years old with a Medtronic Mosaic bioprosthesis (Medtronic, Inc) together with atrial septal defect closure and right ventricular plication. The nominal size of the prosthesis was 25 ± 0.5 mm external diameter, 22.5 ± 0.5 mm internal diameter, and 18 ± 0.5 mm height. The surgical procedure required right ventricular plication and epicardial Medtronic dual-chamber pacemaker implantation for complete atrioventricular block. Seven years later, the    patient started reporting progressive dyspnea on exertion, easy fatigability, chest discomfort related to hyperdynamic precordium at rest, and loss of appetite, followed by exercise-induced chest pains. Follow-up assessments documented moderate tricuspid stenosis with severe regurgitation and marked limitation of leaflet motion. The case was discussed at the medico-surgical rounds and the indication for valve replacement was decreed. Because of the elevated surgical risk, a percutaneous approach was favored.

Procedural Details

The valved stent was obtained following approval from Health Canada, Special Access Programme. A written informed consent was obtained from the parents, with the patient’s assent. The procedure was performed under general anesthesia, with fluoroscopic and transesophageal echocardiographic (TEE) guidance. Access was obtained via the right femoral vein, and the right femoral artery was cannulated for blood pressure monitoring. Left subclavian venous access was obtained for angiographic guidance. Initial hemodynamic study yielded a 20 mm Hg gradient between the right atrium and the right ventricle, the tricuspid annulus measured 20 mm by fluoroscopy and 19 mm by TEE, which was consistent with computed tomography scan measurements (Figure 1). On fluoroscopy, the Mosaic valve is basically radiolucent, with 3 radioopaque metallic eyelets at the level of the valve comissures, which were utilized as landmarks together with the aid of TEE. 

The stenotic bioprosthetic valve was crossed by a floatation catheter and a super-stiff Amplatzer wire was seated in the left pulmonary artery. A 22 Fr RetroFlex 3 delivery system (Edwards Lifesciences) was used; the valved stent was prepared by crimping over the balloon using a mechanical tool that ensures symmetrical compression of the SAPIEN device. The balloon was previously tested to a maximum diameter of 23 mm in a way that a predetermined volume of the pump syringe would be delivered during deployment without exceeding the nominal preset balloon diameter. The RetroFlex system was passed to the right atrium and curved to enter the right ventricle through the stenotic valve, which failed despite several manipulations with various flexing degrees. Consequently, a valvuloplasty was performed via the other femoral vein using an 18 mm x 4 cm Z-MED balloon (B. Braun). Following valvuloplasty, the RetroFlex system was able to cross the bioprothesis, and the suitable position was determined by the combination of TEE guidance and the radio-opaque landmarks on the Mosaic bioprosthesis (Figure 1). During balloon inflation, a rapid left ventricular pacing at 220 beats/min was performed using his pacemaker, together with controlled apnea. The valve was successfully deployed using the slow inflation technique to allow repositioning of the prothesis as it tends to displace distally. A stable position was assured by a small proximal waist and a distal flair adhering to the shape of the polyester-covered frame of the Mosaic bioprosthesis. Following deployment and termination of ventricular pacing, the right atrial mean pressure dropped immediately to 7 mm Hg, with mild central regurgitation noted on TEE, and no perivalvular leak (Figure 3). The total procedure time was 155 minutes, with fluoroscopic time of 38.3 minutes, radiation exposure of 1985 mGy, and radiopaque contrast solution of 1 mL/kg. Following the intervention, the pacemaker battery was changed surgically. The patient was subsequently transferred to the pediatric intensive care unit to be extubated a few hours later. On the following day, SAPIEN prosthesis position was intact and its function was unchanged by fluoroscopy and echocardiography. The peak transvalve pressure gradient was 8 mm Hg, with a mean of 4 mm Hg. The patient was discharged from the hospital on the third day on daily antiplatelet dose of aminosalicylic acid. On follow-up 10 days and 2 months later, the patient reported freedom of all previously experienced symptoms.

Discussion

This is the second pediatric case to receive a percutaneous tricuspid SAPIEN valve (the first was with an Edwards Carpentier bioprothesis),14 the fourth pediatric case using either SAPIEN or Melody valves, and one of the first few cases to receive a SAPIEN valve in the tricuspid position.9,14-16 In our case, the percutaneous route was based on the estimated surgical difficulties and the potential complications inherent to the dissection, the proximity to the right coronary artery, and the complex extraction of the in situ prosthesis on a surgically-plicated right ventricle. In an Ebstein’s anomaly requiring tricuspid valve replacement, the functional right ventricle is typically small in size, often a bipartite with severely underdeveloped right ventricular apex. The SAPIEN valve was preferred in our case because of its shorter axial size compared to the Medtronic Melody valve (14 mm for the 23 mm valve and 16 mm for the 26 mm valve). As the inserted SAPIEN valve is nearly fully covered by the pre-existing Mosaic valve hard structure, there is essentially no chance that the SAPIEN stent would perforate the myocardium in the future. Although never reported, a longer stent could hypothetically represent such a risk. In addition, the SAPIEN valve has a sturdier structure (stainless-steel frame) as opposed to the Melody stent (platinum-iridium frame), which is prone to fracture as reported for the valve in the right ventricle to pulmonary artery conduit position. The Melody-valved stent fractures are thought to be caused by external compression in the retrosternal position.18-20 One might argue that in the tricuspid position, a Melody valve may be at a lower risk, as there are no reports of fracture in the short series, neither in the tricuspid position nor within a right atrium to right ventricle conduit.16

In a 15-case series using the Melody valve system to palliate right atrioventricular valve defect, 10 were in the tricuspid position, and 5 in a right atrium to right ventricle conduit.16 Among the tricuspid position cases, 7 required postdilatation, which did not seem to cause significant regurgitation. 

The first use of the SAPIEN valve in the tricuspid position was via a transatrial approach in an elderly patient.9 The jugular approach was favored in one report using the SAPIEN system14 and in 4 out of 15 in a Melody valve case series having an aligned route to the tricuspid valve.16 In our case, we preferred the femoral approach because of the large sheath size, and also because the in situ prosthetic valve orientation was not particularly oriented to favor the jugular approach. With the availability of the flexible catheters that can align the valved stent in a coaxial position to the dysfunctional valve, the SAPIEN delivery system may be fit for either delivery approach. Nevertheless, selection of the approach should be tailored to each case considering the structural anatomy, body habitus, and the type of valve used. There is, however, a practical limitation to the RetroFlex system despite its flexing capability. In fact, the delivery catheter, which is designed to spouse the sharp curve of the aortic arch, was difficult to slide over the wire in a dilated right atrium when the flex capability was used. This was particularly felt in trying to cross the stenotic degenerated valve in our case. The predilatation was therefore necessary. A different balloon delivery system, which would typically advance over a long delivery sheath, might have been easier to advance over the wire across the stenotic lesion, bearing in mind that the main advantage we were seeking for our patient was the valved stent itself for its particular characteristics described above. 

Another particularity of using the SAPIEN system in the right heart position is the fact that the valve must be loaded in a reverse orientation compared to the aortic position. This may represent some technical challenges as addressed previously where a retrograde loading technique was performed on the NovaFlex delivery system following a few successful bench testings.14 This was not required in our case since a 22 Fr sheath was appropriate for the patient with no need to down-size the access to 16 Fr. Inverted loading of the SAPIEN-XT valve on the NovaFlex+ delivery system, which requires that the valve be crimped proximal to the deployment balloon and aligned in the descending aorta prior to deployment in cases of aortic valve treatment, is outside of the device indication, and therefore is not recommended by the manufacturer.

Conclusion

We report the successful implantation of an inverted Edwards SAPIEN valve to treat severe dysfunction of a Mosaic bioprosthetic valve in a teenager. The limited worldwide experience offers an encouraging alternative to open-heart surgery. Nevertheless, new developments may become necessary in the future in a search for dedicated material.

Acknowledgment. We thank Dr Suzanne Vobecky, the patient’s surgeon, for her support and for providing surgical back-up during the procedure. We also thank Dr Marie-Josée Raboisson for TEE guidance.

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