SAPIENTM Valve Research Articles

Impact of proficiency in the transcatheter aortic valve implantation procedure on clinical outcomes: a single center retrospective study

BackgroundWe used transcatheter aortic valve implantation (TAVI) procedure time to investigate the association between surgical team maturity and outcome.MethodsAmong patients who underwent TAVI between October 2015 and November 2019, those who had Sapien™ implanted with the transfemoral artery approach were included in the analysis. We used TAVI procedure time and surgery number to draw a learning curve. Then, we divided the patients into two groups before and after the number of cases where the sigmoid curve reaches a plateau. We compared the two groups regarding the surveyed factors and investigated the correlation between the TAVI procedure time and survey factors.ResultsNinety-nine of 149 patients were analysed. The sigmoid curve had an inflection point in 23.2 cases and reached a plateau in 43.0 cases. Patients in the Late group had a shorter operating time, less contrast media, less radiation exposure, and less myocardial escape enzymes than the Early group. Surgical procedure time showed the strongest correlation with the surgical case number.ConclusionThe number of cases required for surgeon proficiency for isolated Sapien™ valve implantation was 43. This number may serve as a guideline for switching the anesthesia management of TAVI from general to local anesthesia.

Cathétérisme interventionnel dans les cardiopathies congénitales

Interventional cardiac catheterization has a major place in the management of congenital heart disease. Since the Rashkind atrioseptostomy in mid-1960s, many techniques have been developed. For some, it is necessary to close a cardiac or extracardiac shunt using occluder (double disc system, plug, coil…): closure of atrial septal defect, ventricular septal defect or patent arterial duct. For others, it is necessary to treat a valvular or vascular stenosis using a balloon catheter: dilatation of the pulmonary or the aortic valve, dilatation of aortic coarctation. For vascular stenosis, balloon angioplasty may be associated with stent implantation. Moreover, since more than 10 years, valve implantation can be performed: initially for pulmonic valve (the Melody™ valve from Medtronic or the Sapien™ valve from Edwards Lifesciences); but probably, most of the valves in the future could be implanted using appropriate tools and hybrid techniques combining cardiac catheterization and surgery. All these techniques were developed because of progress in fluoroscopy, and more recently association of different imaging techniques (echocardiography, MRI and CT) provides more information about the true anatomy. Interventional cardiac catheterization will continue to increase with use of new tools as 3D printing, tissue engineering and nano-techniques. It seems that from correction with open-heart surgery, many lesions could be repaired in future by hybrid techniques without opening the heart.

Percutaneous pulmonary valve implantation for free pulmonary regurgitation following conduit-free surgery of the right ventricular outflow tract

IntroductionPulmonary regurgitation (PR) following surgery of the right ventricular outflow tract (RVOT) is not innocent and leads to significant right heart dysfunction over time. Recent studies have demonstrated that percutaneous valves can be implanted in conduit free outflow tracts with good outcomes. ObjectivesTo evaluate in patients with severe PR – anticipated to require future pulmonary valve replacement – the feasibility and safety of pre-stenting dilated non-stenotic patched conduit-free right ventricular outflow tracts before excessive dilation occurs, followed by percutaneous pulmonary valve implantation (PPVI). Patients and methodsTwenty seven patients were evaluated, but only 23 were deemed suitable based on the presence of an adequate retention zone ≤24mm defined by semi-compliant balloon interrogation of the RVOT. A 2 step procedure was performed: first the landing zone was prepared by deploying a bare stent, followed 2months later by valve implantation. ResultsRVOT pre-stenting with an open cell bare metal stent (Andrastent XXL range) was performed at a median age of 13.0years (range: 6.0–44.9) with a median weight of 44.3kg (range: 20.0–88.0). Ninety six percent (22/23) of patients proceeded to PPVI a median of 2.4months (range: 1.4–3.4) after initial pre-stent placement. Twenty one Melody valves and one 26mm Edwards SAPIEN™ valve were implanted. Complications consisted of embolization of prestent (n=1), scrunching (n=4) and mild stent dislocation (n=2). During follow-up, no stent fractures were observed and right ventricular dimensions decreased significantly. ConclusionsPost-surgical conduit-free non-stenotic RVOT with free pulmonary regurgitation can be treated percutaneously with a valved stent if anatomical (predominantly size) criteria are met. In experienced hands, the technique is feasible with low morbidity.

Experimental Validation of SAPIENTM Transcatheter Heart Valve Finite Element Analysis Models

The Edwards SAPIENTM transcatheter heart valve is designed for heart-valve replacement in patients with severe aortic stenosis without open-heart surgery. Physiological finite element analysis (FEA) has been performed to provide an assessment of the fracture and fatigue resistance of the device during deployment and operation. Experimental validation is an essential step in establishing the credibility of computational modeling and simulation [1,2]. The present study validates FEA frame models by comparing the crimping behavior of the FEA models with the results of crimping experiments. FEA models for the Edwards SAPIENTM transcatheter-heart-valve frames were created to assess the structural integrity and durability of the frame, in conjunction with a number of accelerated reliability tests. When a SAPIENTM valve is prepared for delivery, the valve is reduced in diameter onto a delivery catheter using a radial force fixture called a “crimper”. During crimping, the frame deforms elastically at the beginning of crimping, and later, the struts experience large displacements and substantial plastic deformation to achieve the desired diameter reduction. This crimping step includes all the representative deformation modes encountered during the full physiological FEA simulation. Therefore, a rigorous physical crimping experiment was developed to validate the FEA models, encompassing the full range of elastic and plastic deformation experienced during the physiological simulations. Specifically, crimping experiments were conducted using a radial force test system to compare the measured structural response of the frame to an FEA simulation. Figure 1Fig. 1Configuration of the radial force test system shows the radial force test system (MSI Radial Force tester model RX650). The results of the experiment were then compared with the predictions of the FEA models.Two FEA models of SAPIENTM valve frames were constructed using abaqus/standard [3]. These two frame models included representative design conditions in the simulation of the crimping process. The dimensional range of these models encompassed the dimensions of the physical test specimens: one at the low end and the other at the high end. After simulation, the resultant force-diameter curves were extracted from the FEA output database. Crimping experiments were performed using actual SAPIENTM valve frames as the test specimens. The radial force tester progressively reduced the diameter of each frame specimen by applying a uniform radial displacement through an array of 12 radial displacement elements [4]. The reaction force at each element was measured by instrumentation integral to the radial force test device. The radial force was continuously measured along with the outside diameter of the frame during the crimping process. After the crimp test, the resultant force-diameter curves were extracted and compared with the resultant force-diameter curves from FEA. The test system compliance was measured to compensate for the elastic deformation of the loading mechanism.The force-diameter curve defines the structural response of the frame over the complete crimping cycle. Qualitatively, by plotting the curves on the same axes, the curves of the FEA can be seen to agree well with the curves from the physical experiments (Fig. 2). Quantitatively, the curves can be compared using parameters such as radial strength, radial stiffness, and average crimping force. These parameters represent important crimping attributes and span the complete range of elastic and plastic deformation of the frame during the crimping process. A linear regression was performed for each parameter using the simulation results and the experimental data. Figure 3 shows an example of radial strength comparison for the experimental and FEA data. The radial strength represents the force at which plastic-frame deformation occurs. All experimental data points fall within 5% of the linear relationship established from the FEA simulation predictions. Validating a simulation model also aids in assuring the expected in vivo behavior of the implant. The adequacy of the radial strength is evaluated in a verified model and is confirmed clinically. Wilson et al. [5] have demonstrated the SAPIENTM and SAPIEN XTTM design success and have reported 98% circularity upon implantation.Finite element analyses of SAPIENTM valve frames were conducted to simulate the crimping process. The analogous crimping test was performed on SAPIENTM frames using a radial force test system. The force-diameter curves from FEA agree well with those from the physical experiments, capturing the important transition points and following similar slopes. Furthermore, the FEA simulation results are within 5% of the physical experiments for all three important frame characteristic parameters (radial strength, radial stiffness, and average crimping force). This good agreement validates the FEA models for the Edwards SAPIENTM transcatheter heart valve frames and demonstrates high credibility for their use in stress analyses and fatigue life analysis.

Early percutaneous valve failure within bioprosthetic tricuspid tissue valve replacements

To describe the cases of percutaneous valve failure following implantation of the Medtronic Melody™ and the Edwards Sapien™ valve in the tricuspid position. There have been recent reports of the use of percutaneously delivered valves to manage failing bioprosthetic tricuspid valves. Total patient numbers remain small and follow-up times are limited. We describe four procedures in three patients from two centers where implantation of percutaneous valves within the scaffold of a bioprosthetic tricuspid valve was technically successful but there was early valve failure. In all cases, immediate results suggested excellent valve function; however, valve failure occurred early in three and later in one. Two patients elected for valve explantation and surgical placement of a further tricuspid valve. The third patient underwent a second percutaneous valve-in-valve procedure though this valve is also showing early signs of failure. Transcatheter placement of percutaneous valves in the tricuspid position is technically a relatively straightforward procedure but early valve failure raises some concerns about the viability of the valve in this position, at least in some patients.

Aortic regurgitation after transcatheter aortic valve implantation of the edwards SAPIENtm valve

Introduction. Transcatheter aortic valve implantation (TAVI) is established as an attractive treatment option for high-risk patients with aortic valve stenosis. One concern is the high risk of prosthetic valve regurgitation. This study aimed to examine for potential preoperative risk factors for postprocedural transcatheter heart valve regurgitation and to quantify the risk, degree, and consequences of postprocedural regurgitation. Materials and methods. 100 consecutive patients who underwent femoral (n = 22) or transapical (n = 78) TAVI were retrospectively reviewed. Echocardiographic valve regurgitation and clinical parameters were analyzed over the first year after TAVI. Results. Seventy-five percent of all patients had prosthetic valve regurgitation. It was, however, only mild or absent in 64% of patients and did not require re-intervention in any of the patients in the series. The severity of the regurgitation appeared unchanged over the one-year follow-up period. Moderate to severe regurgitation was associated with significant yet stable dilatation of the left ventricle over one year and lesser NYHA class improvement three months after TAVI. Asymmetrical native valve calcification increased the risk of paravalvular regurgitation non-significantly. Conclusion. Transcatheter heart valve regurgitation seems to be mild in the majority of cases and unchanged over a 12 months follow-up period. While affecting left ventricular dimensions in moderate or severe cases, we observed no obvious undesirable consequences of the prosthetic valve regurgitation within the first year.

Transapical aortic valve implantation with anatomically oriented prostheses.

Transcatheter aortic valve implantation (TAVI) is an accepted treatment option for elderly high-risk patients with aortic valve stenosis (1). Obvious advantages are the avoidance of a sternotomy and cardio-pulmonary bypass. Two devices are mainly used, the SapienTM Valve (Edwards Lifesience, USA) and the CoreValveTM (Medtronic, USA). The SapienTM prosthesis is implanted either transfemorally or transapically whereas the CoreValveTM prosthesis is almost exclusively implanted transfemorally. A major concern in TAVI procedures is malpositioning of the valve prosthesis which can lead to paravalvular or transvalvular regurgitation (AR) (2), or cause coronary obstruction (CO) (3). CO is a rare but severe complication occurring at a rate of 1 to 2% (4,5). In contrast, paravalvular regurgitation is relatively common: In the patient population from the German transcatheter aortic valve interventions registry, almost one fifth of the patients showed moderate to severe AR immediately after implantation. AR was a strong independent predictor of in hospital death but no follow-up data were published (6). The 2 year follow-up results of the Partner trial showed that moderate or severe paravalvular leakage as seen in 6.9% of patients post TAVI was associated with an increase in late mortality and directly correlated with the severity of the paravalvular leakage (7). Those results underline the importance of a perfect placement of transcatheter aortic valve prostheses. To address those complications three devices have been launched lately: The Medtronic EngagerTM System, the Symetis AccurateTM Valve and the JenaValveTM. All three valves are designed for transapical implantation and have different mechanisms to facilitate positioning in an anatomically oriented position.

Percutaneous pulmonary valve replacement

Each year in the United States more than 4000 newborns are diagnosed with complex congenital heart disease involving right ventricular outflow tract obstruction. Despite advances in surgical techniques with right ventricle to pulmonary artery conduits, progressive conduit failure often occurs within 4–12years. Consequently, the majority of these patients, prior to becoming adults, require 2–4 operations for the right ventricle outflow tract to reverse the adverse ventricular effects of a volume or pressure load. Fortunately, over the past decade, percutaneous pulmonary valve replacement has emerged as a nonsurgical intervention for right ventricle to pulmonary artery conduit failure.Currently, there are two percutaneous pulmonary valves available in the United States with the Edwards SAPIEN™ valve actively enrolling in a Phase II FDA approved clinical trial, and the Medtronic Melody® valve now FDA approved through a Humanitarian Device Exception pathway. In this article, we review indications, technique and outcomes for percutaneous pulmonary valve replacement and compare and contrast the available percutaneous stent valves.

Immediate Results and Clinical Follow-up of Patients Undergoing Transcatheter Aortic-Valve Implantation

Background: One third of the elderly population with symptomatic calcified aortic stenosis cannot undergo surgery due to their high operative risk. The transcatheter aortic-valve implantation (TAVI) has emerged as an alternative therapy for this group of patients. Methods: All patients submitted to TAVI from November 2008 to April 2012 were included in our study. We report the baseline clinical characteristics, procedural data, hospital outcomes and clinical follow-up of this population. Definitions were based on the Valve Academic Research Consortium criteria. Results: TAVI was performed in 23 patients, with 79  6.7 years of age, and 56% were female. The EuroSCORE was 20.4  11.1%. The CoreValve  prosthesis was used in 19 patients (82.6%) and the Edwards SAPIEN™ valve was used in the remaining ones. Procedure success rate was 96%. The mean follow-up was 22  12.8 months, with 6 deaths (26.1%) in this period, 3 of which were observed in the first 30 days (13%) and other 2 (21.7%) by the end of the first year. One patient had a transient ischemic attack during hospitalization (4.3%), but there were no episodes of stroke or myocardial infarction in the periprocedural period or in the follow-up. The composite safety endpoint at 30 days was observed in 5 patients (21.7%) and the composite efficacy endpoint at 12 months was 78.3%. Conclusions: The results of this study demonstrate that TAVI is an attractive procedure for

Resultados imediatos e seguimento clínico dos pacientes submetidos a implante valvar aórtico transcateter

INTRODUÇÃO: Um terço da população idosa portadora de estenose aórtica calcificada sintomática não apresenta condições cirúrgicas em decorrência do elevado risco operatório. O implante valvar aórtico transcateter (IVAT) surgiu como uma alternativa terapêutica para esses pacientes. MÉTODOS: Incluímos, no período de novembro de 2008 a abril de 2012, todos os pacientes submetidos a IVAT em nosso serviço. Relatamos as características clínicas basais, os dados dos procedimentos, os resultados hospitalares e o seguimento clínico dessa população. As definições utilizadas foram baseadas nos critérios do Valve Academic Research Consortium. RESULTADOS: O IVAT foi realizado em 23 pacientes, com 79 ± 6,7 anos de idade, 56% do sexo feminino. O EuroSCORE foi de 20,4 ± 11,1%. A prótese CoreValve® foi utilizada em 19 pacientes (82,6%) e a Edwards SAPIEN TM nos demais. A taxa de sucesso do procedimento foi de 96%. O tempo médio de seguimento clínico foi de 22 ± 12,8 meses, observando-se 6 óbitos (26,1%) nesse período, 3 dos quais ocorreram nos primeiros 30 dias (13%) e outros 2 (21,7%), até o final do primeiro ano. Um paciente apresentou ataque isquêmico transitório na fase hospitalar (4,3%), mas não ocorreram episódios de acidente vascular encefálico ou de infarto do miocárdio no período periprocedimento ou no acompanhamento tardio. O desfecho combinado de segurança aos 30 dias ocorreu em 5 pacientes (21,7%) e o desfecho combinado de eficácia aos 12 meses foi de 78,3%. CONCLUSÕES: Os resultados obtidos neste estudo demonstram o IVAT como procedimento atrativo para o tratamento de pacientes portadores de estenose aórtica calcificada de alto risco cirúrgico.

A rescue option procedure post-transapical transcatheter aortic-valve implantation†

I have read with great interest the article by Kempfert et al. [1] ‘A second prosthesis as a procedural rescue option in transapical aortic valve implantation’. In this article, the authors present the results of a cohort of patients undergoing a second placement of SAPIENTM valve affirming that it is a valuable ‘bailout’ technique in case of VSD, dysfunctional leaflets or too low placement of the first prosthesis. The authors report that approximately 40% of dysfunctional valves is due to ‘malfunctional leaflets’. They state that the VinV only works if the leaflets of the first valve are fully covered by the stent of the second valve. Nevertheless in fig. 2 the valves are not completely covered by a second valve. Moreover, they state that the low positioning was attempted in all cases due to low insertion of the coronary arteries. But a second SAPIENTM prosthesis was successfully implanted in all seven patients in a slightly higher position(in the direction of the ascending aorta). How could the authors explain that? Is it correct to define these leaflets as ‘malfunctioning’? The second valve with the same size would then overextend the first one increasing at the same time the radial forces and thus eliminating much of the ‘recoil’ effect. Do not the authors think that it would be better reballoonig the first valve implanted avoiding the rupture of the leaflets? Finally, I would like to know whether the authors have a pacing problem during the first procedure and whether there was a correct axis between the valve plane and prosthesis during valve displacement with transapical implant.

Trans-apical aortic valve implantation using a new self-expandable bioprosthesis: initial outcomes

Trans-apical aortic valve implantation (TA-AVI) has evolved into a standard approach for high-risk, elderly patients using the balloon-expandable Edwards SAPIEN™ prosthesis. As an alternative device, a self-expanding sub-coronary trans-apical bioprosthesis was evaluated. The Symetis Acurate™ trans-catheter heart valve is composed of a porcine biologic valve attached to a self-expandable nitinol stent. It allows for anatomical orientation, and facilitates intuitive implantation providing tactile feedback. Three valves sizes were available to treat patients with an annular diameter between 21 and 27mm. Since November 2009, a total of 40 patients have been treated at three sites. Patient age was 82.8±4 years, 60% were female, logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 21.5±10.9% and Society of Thoracic Surgeons (STS) Score was 9.0±4.6%. All implants were delivered successfully in the intra-annular and sub-coronary position off pump. One patient was converted to conventional surgery due to coronary impingement; post-dilatation was performed in 45% of patients; and two patients required the SAPIEN™ valve in valve implantation. Echocardiographic and angiographic control revealed no/trivial aortic incompetence (AI) in 59%, mild AI in 33.3%, and moderate AI in 7.7% of the patients. Three patients died within 30 days from a non-valve-related cause (respiratory), the patient converted did not recover from right-heart failure, and one patient died on day 19 due to unclear reasons. There was one incidence of new-onset atrioventricular (AV) block requiring pacemaker implantation. Two patients suffered a stroke (one secondary and the other intraprocedural). Transvalvular gradients were maximum 29.4±10.7mmHg and mean 14.3±6.8mmHg. The initial clinical results indicate a relatively straightforward implantation procedure and good functional results after trans-apical implantation of the Symetis Acurate™ device.

A second prosthesis as a procedural rescue option in trans-apical aortic valve implantation

Trans-apical aortic valve implantation (TA-AVI) using the Edwards SAPIEN™ prosthesis has evolved to a routine procedure for selected high-risk elderly patients. In rare cases, misplacement of the SAPIEN™ valve (too low a position), dysfunction of the leaflets or perforation of the interventricular septum (ventricular septal defect, VSD) occurs and requires immediate implantation of a second prosthesis within the first one. Results of this 'bailout' maneuver have not been reported yet. Of 305 TA-AVI procedures, 15 patients required a second prosthesis due to dysfunctional leaflets (n = 6), low position (n = 7), or VSD (n = 2). Mean age was 82.5 ± 1.3 years, mean logistic EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 45.5 ± 5.4, and Society of Thoracic Surgeons (STS) Score was 13.5 ± 1.5. All second SAPIEN™ valves could be implanted successfully within the first one. The second prosthesis solved leaflet dysfunction, sealed the VSD (lower position of the second prosthesis), or corrected the initial misplacement (higher position of the second prosthesis) in all patients. Within 30 days, four patients died (low cardiac output n = 3, all with preoperative ejection fraction (EF) <35%; intestinal ischemia n = 1). Intra-operative echocardiogram and angiogram revealed mild paravalvular leak in three and none/trace in 12 patients. Transvalvular gradients were low despite the implantation of the second valve (P(max)/mean 13.7 ± 4.3/6.4 ± 2.0). Placement of a second SAPIEN™ valve is a valuable 'bailout' technique in case of VSD, dysfunctional leaflets, or too low placement of the first prosthesis. The technique leads to an excellent functional result with low transvalvular gradients. The simple, straight, tubular stent design of the SAPIEN™ prosthesis may be the ideal design for such valve-in-valve procedures.

Single center experience with transcatheter aortic valve implantation using the Edwards SAPIEN™ Valve

Objectives. The use of transcatheter aortic valve implantation (TAVI) for high-risk patients was introduced in the early 2000s for treatment of aortic valve stenosis patients with too high surgical risk. During the last years, there has been a dramatic increase in TAVI procedures. TAVI programs are implemented in numerous cardiac centers. This paper describes a single center experience with its first 100 TAVI procedures. Methods. This study included the first 100 patients who were scheduled for either transfemoral (F-TAVI) or transapical (A-TAVI) aortic valve implantation at Aarhus University Hospital, Skejby, using the Edwards SAPIEN™ valve. The indication for TAVI was unacceptable high predicted risk associated with conventional surgery. Patients with adequate diameter of iliac arteries were scheduled for F-TAVI, otherwise A-TAVI was preferred. Results. The patients were treated between February 2006 and June 2010. Of these were 44% males and 56% females with a mean (S.D.) age of 81 (7.0). Thirty-days mortality rate was 8%, and decreased from 12% among the first 50 patients to 4% for the last 50 patients. Successful implantation was achieved in 92% patients. Major non-fatal complications were seen in 5% of 76 A-TAVI and in 0% of 24 F-TAVI patients. Mean (S.D.) EuroSCORE in the F-TAVI and A-TAVI groups was 15.9 (9.4) and 21.5 (14), respectively (p = 0.06). Post-procedural leakage of cardiac biomarkers was significantly higher in the A-TAVI group as compared to in the F-TAVI group. Mean (S.D.) NYHA class improved from 2.9 (0.6) to 1.8 (0.7) p < 0.001, with no significant difference between A-TAVI and F-TAVI patients. Conclusion. In surgically non-amenable patients, TAVI can be performed with acceptable mortality and morbidity and results in marked functional improvement. A decrease in 30-day mortality over time indicated a learning curve when implementing this treatment.

AS-086 Transcatheter Aortic Valve Insertion. Can We Afford Not To Be Involved?

Transcatheter aortic valves have been implanted in New Zealand since August 2008 for severe, symptomatic aortic stenosis (AS) in patients considered high risk for traditional surgical valve replacement. The self expanding Medtronic CoreValve™ (CV) and balloon expandable Edwards Sapien™ (EV) valve were used. We describe our experience with cost-effective analysis.

Transcatheter Aortic Valve-in-valve Implantations for Failed Bioprosthetic Heart Valves at the Prince Charles Hospital

Conclusions: Our data suggests that TAVI may be a viable alternative to conventional surgical aortic valve replacement in this high risk cohort of patients. doi:10.1016/j.hlc.2011.05.379 377 Transcatheter Aortic Valve Implantation (TAVI). Can We Afford Not to be Involved? S. Pasupati 1,∗, G. Devlin1, M. Liang1, D. Kelly 1, R. Fisher 1, N. Kejriwal 2, A. El-Gamel 2 1Department of Cardiology, Waikato Hospital, Hamilton, New Zealand 2 Department of Cardiothoracic Surgery, Waikato Hospital, Hamilton, New Zealand Background: Transcatheter aortic valves have been implanted inNewZealand sinceAugust 2008.Wedescribe our experience with cost-effective analysis. Methods: TAVI has been implanted for severe, symptomatic aortic stenosis (AS) in patients considered high risk for traditional surgical valve replacement using Medtronic CoreValveTM (MCV) and Edwards SapienTM (ESV) valve via trans-arterial or trans-apical access. All patients with severe AS over a year period who received surgical aortic valve replacement (SAVR) in our institution were used for cost-effective analysis. This included t t a

Peri-Procedural Complications and 30 days Outcomes from Transcatheter Aortic Valve Implantation (TAVI) via Transarterial Method Using Both Medtronic CoreValve™ and Edwards Sapien™ Valve at Waikato Hospital, Hamilton, New Zealand

Peri-Procedural Complications and 30 days Outcomes from Transcatheter Aortic Valve Implantation (TAVI) via Transarterial Method Using Both Medtronic CoreValve™ and Edwards Sapien™ Valve at Waikato Hospital, Hamilton, New Zealand