Summary
Background
A new generation of balloon-expandable valves (e.g. Edwards SAPIEN XT) enables the use of a decreased sheath size using the NovaFlex™ delivery system for transfemoral transcatheter aortic valve implantation (TAVI). However, there are few data analysing the efficacy and safety of this new prosthesis.
Aims
To evaluate periprocedural and 30-day clinical outcomes using the Edwards SAPIEN XT compared with the first-generation Edwards SAPIEN prosthesis.
Methods
Between May 2006 and October 2011, consecutive high-risk or non-operable patients with severe aortic stenosis had TAVI using an Edwards SAPIEN or SAPIEN XT prosthesis. Valve Academic Research Consortium endpoints were used.
Results
Of 250 patients who underwent TAVI, 190 were performed transfemorally (78 SAPIEN and 112 SAPIEN XT). Transfemoral access was possible more often using SAPIEN XT (112/123 [91.1%] vs 78/127 [61.4%]; P < 0.001). Mean logistic EuroSCORE was significantly lower in the SAPIEN XT group (18.1 ± 11.0% vs 27.3 ± 11.1%; P < 0.0001), and the iliofemoral artery minimal lumen diameter was smaller (6.7 ± 1.2 vs 8.5 ± 1.3 mm; P < 0.0001). Device success was similar in both groups (95.5% for SAPIEN XT and 93.6% for SAPIEN), as was the 30-day combined safety endpoint (15.2% and 17.9%, respectively). At 30 days, prosthesis performance was similar in both groups.
Conclusions
Short-term safety and performance analysis of the latest generation of balloon-expandable valve, the SAPIEN XT, seem similar to the previous generation. However, transfemoral implantation is more often possible, related to sheath size reduction.
Résumé
Contexte
Des améliorations techniques ont permis récemment le développement d’une nouvelle génération de bioprothèses aortiques, la valve Edwards SAPIEN XT, permettant principalement de diminuer la taille des désilets nécessaires lors de son implantation par voie transfémorale. Cependant, il y a peu de données analysant l’efficacité et la sécurité de cette nouvelle prothèse.
Buts
Évaluer la sécurité et l’efficacité de la valve Edwards SAPIEN XT en comparaison avec le modèle de première génération, la valve Edwards SAPIEN.
Méthodes
Entre mai 2006 et octobre 2011, 190 patients consécutifs présentant un rétrécissement aortique considérés à haut risque ou non opérables, ont été traités par l’implantation d’une bioprothèse aortique par voie transfémorale en utilisant soit la valve Edwards SAPIEN ( n = 78), soit le modèle SAPIEN XT ( n = 112). Les critères de jugement ont été évalués selon les définitions de la Valve Academic Research Consortium (VARC).
Résultats
L’Euroscore logistique était significativement plus bas dans le groupe SAPIEN XT que dans le groupe Edward SAPIEN (18,1 ± 11,0 % vs 27,3 ± 11,1 % ; p < 0,0001). Le diamètre minimal de la lumière artérielle était plus petit dans le groupe SAPIEN XT (6,75 ± 1,17 vs 8,53 ± 1,32 mm ; p < 0,0001). Un abord transfémoral a été plus souvent possible avec la valve SAPIEN XT (91,1 % vs 61,4 % ; p < 0,001). Le succès de la procédure a été similairement élevé dans les deux groupes (95,5 % vs 93,6 % ; p = 0,65). Le critère combiné de sécurité à 30 jours selon les définitions VARC s’est avéré comparable dans les deux groupes (15,2 % vs 17,9 % ; p = 0,61). À 30 jours, la performance des deux modèles de valve était identique (gradient moyen aortique : 9,6 ± 2,6 vs 9,8 ± 3,7 mm Hg ; p = 0,76 ; régurgitation aortique ≥ grade III : 4,3 % vs 3,2 % ; p = 0,92).
Conclusions
La performance et les taux de complications à 30 jours de la nouvelle valve SAPIEN XT implantée par voie transfémorale semblent similaires à ceux de la valve SAPIEN de première génération. Cependant, grâce à la réduction de taille du matériel, un abord par voie transfémorale est maintenant possible dans 90 % des cas.
Background
Since the first-in-man transcatheter aortic valve implantation (TAVI) in 2002, many registries have shown that TAVI can be accomplished in non-operable and high-risk patients with outcomes that compare favourably with surgical aortic valve replacement . This has been observed with the two devices currently in use: the balloon-expandable Edwards SAPIEN (Edwards Lifesciences LLC, Irvine, CA, USA) and the self-expandable Medtronic CoreValve (Medtronic CV, Irvine, CA, USA) prostheses.
The first-generation balloon-expandable valve (Edwards SAPIEN) required 22 F and 24 F sheaths for the 23- and 26-mm valve sizes, respectively, for transfemoral insertion using the RetroFlex™ delivery system. The large sheath size was the most important limitation of this technique. Since October 2009, subsequent technical and procedural improvements have allowed the development of a new generation of balloon-expandable valves such as the Edwards SAPIEN XT, which decreased the required sheath size to 18 F and 19 F, respectively, using the NovaFlex™ delivery system.
Using the SAPIEN valve, the pivotal randomized Placement of Aortic Transcatheter Valve Trial US (PARTNER-US) trial demonstrated the superiority of TAVI over standard care, with a marked reduction in the mortality rate at 1 year in non-surgical candidates and a similar rate of survival at 1 year with TAVI and surgical aortic valve replacement in high-surgical-risk patients . Only limited data, however, are available for the Edwards SAPIEN XT valve . Thus, we sought to compare 30-day clinical outcomes in our prospective registry using Edwards SAPIEN XT and SAPIEN prostheses.
Methods
Patient selection and evaluation
Between May 2006 and October 2011, consecutive high-risk patients underwent TAVI using balloon-expandable Edwards prostheses, and were included in a prospective, single-centre registry. All patients had severe, degenerative symptomatic aortic stenosis. The indication for TAVI was based on the decision of the medicosurgical team. The patients were considered candidates for TAVI when their logistic EuroSCORE was greater or equal to 20%, in case of frailty, or in case of comorbidities contraindicating surgical aortic valve replacement. All patients provided signed informed consent for subsequent data collection and analysis for research purposes.
The screening process included transthoracic echocardiography (TTE), selective coronary angiography, aortography, iliofemoral angiography and computed tomography (CT) of the aorta and iliofemoral access. Transoesophageal echocardiography was not used in our institution to assess aortic annulus diameter. All patients with unstable haemodynamics were stabilized with balloon aortic valvuloplasty (BAV) before TAVI.
An annulus diameter of 18–21 mm was considered appropriate for the 23-mm prosthesis and 21–24 mm for the 26-mm prosthesis. In cases of borderline sizes (20.5–21.5 mm), aortography was performed during balloon predilatation with a 23-mm balloon, and the optimal valve size was selected based on the presence or absence of aortic regurgitation at full balloon inflation.
CT was crucial to assess the feasibility of a transfemoral approach. A minimum diameter of 7 and 8 mm was required for the 23- and 26-mm SAPIEN valves, respectively, and 6 and 6.5 mm for the 23- and 26-mm SAPIEN XT valves, respectively. Before percutaneous implantation, tortuosities, as well as the absence of calcified plaque at the area of femoral puncture site, were assessed to confirm the suitability for a femoral approach.
Devices
The procedures were performed using the SAPIEN valve ( Fig. 1 A) up to October 2009 and the SAPIEN XT valve ( Fig. 1 B) thereafter. The SAPIEN valve ( Fig. 1 A) is made of three bovine pericardial leaflets, matched for elasticity and thickness, sewn onto a stainless steel stent frame partially covered with a synthetic polyethylene terephthalate fabric sealing cuff. The prosthesis is crimped directly onto the balloon of the RetroFlex™ delivery system ( Fig. 1 C), the outer diameters of which are 8.4 and 9.2 mm for the 23- and 26-mm SAPIEN valves, respectively. The SAPIEN XT valve ( Fig. 1 B) is made of a cobalt chromium frame with thinner struts and a more open cell structure to allow tighter crimping. The valve is crimped over the shaft of the NovaFlex™ delivery system ( Fig. 1 D) and mounted on the balloon after introduction into the abdominal aorta. The NovaFlex™ delivery system allows a reduction in sheath size to 18 F (outer diameter 7.2 mm) and 19 F (outer diameter 7.5 mm) for the 23- and 26-mm valve sizes, respectively.
Patient preparation and procedure
Cardiac catheterization and premedication
All procedures were performed in a conventional cardiac catheterization laboratory with sterile precautions, using local anaesthesia and conscious sedation in all cases. Surgical arterial cut-down was performed by our cardiac surgeon for SAPIEN implantation, whereas most cases were performed using a percutaneous approach with pre-closing for SAPIEN XT implantation. For the latter approach, the cardiac surgeon was not always present. All of the equipment was present and ready to use in the catheterization laboratory, and both the anaesthesiologist and the echocardiographer were immediately available in the event of any complication.
Patients were preloaded with aspirin (160 mg) and clopidogrel (300 mg), and continued clopidogrel (75 mg) for 1 month and aspirin (75–160 mg) indefinitely. Heparin (5000 IU) was administered immediately after surgical cut-down or placement of the vascular closure device.
Local anaesthesia and sedation
Lidocaine 2% (20–30 mL) was used for local anaesthesia, injected into the skin and subcutis, and around the femoral artery for percutaneous and surgical approaches. Additional doses of lidocaine could be administered at any time during the procedure at the discretion of the operator. Conscious sedation consisted of intravenous administration of midazolam (1 mg) and nalbuphin (5 mg) at the start of the procedure. Additional half or full doses of each could be administered at the discretion of the operator during the course of the procedure.
Procedure
The techniques of SAPIEN and SAPIEN XT valve implantation have been described in detail elsewhere . Briefly, in our centre, supravalvular aortography was performed to select the optimal view, aligning all cusps in a single plane. The selected femoral artery was cut-down or ‘pre-closed’ with a 10 F Prostar XL™ (Abbott Inc., Chicago, IL, USA). After crossing the aortic valve, a 260-cm long 0.035 inch Amplatz Extra-Stiff J-tip guidewire (COOK, Bjaeverskov, Denmark) was placed in the left ventricle. BAV was performed with rapid ventricular pacing (180–220 beats/min) using a 20- or 23-mm balloon in accordance with the valve size. Valve positioning was based on fluoroscopy, using annular calcification as a landmark, and serial (5–10 mL) supra-annular aortography to validate the position of the valve during rapid ventricular pacing. The prosthesis was also delivered using rapid ventricular pacing. Removal of the sheath was cautiously achieved with serial contralateral angiograms to detect iliofemoral complications. The femoral arteriotomy was then closed surgically or using the Prostar device. In the absence of a new left bundle branch block or atrioventricular block, the pacing lead was removed at the end of the procedure. Patients were monitored in the intensive care unit for 24 hours after valve implantation.
Data collection
Data on clinical and TTE variables were obtained at baseline, discharge and 1 month, and were entered into our institutional database. In patients from remote institutions, outcomes at 30 days were obtained by telephone interviews of the referring physician and exchange of TTE reports. No patients were lost to follow-up.
Endpoint definitions
The safety endpoint was a combination of all-cause mortality, major stroke, life-threatening bleeding, stage 3 acute kidney injury (AKI), periprocedural myocardial infarction, major vascular complication, and repeat procedure for valve-related dysfunction at 30 days. All complications were reported according to the Valve Academic Research Consortium (VARC) classification .
Other endpoints included: device success according to the VARC definition (i.e. successful vascular access, delivery and deployment of the device, successful retrieval of the delivery system with correct position of the device, post-TAVI aortic valve area greater than 1.2 cm 2 and mean aortic valve gradient less than 20 mmHg or peak velocity less than 3 m/s without moderate or severe prosthetic valve regurgitation), New York Heart Association heart failure functional class, transvalvular mean pressure gradient, effective aortic valve area, presence and severity of aortic valvular regurgitation, and/or mitral valve regurgitation on TTE.
Statistical analysis
Continuous variables are presented as mean ± standard deviation (SD) or median (interquartile range), according to the distribution. Categorical variables are presented as frequencies and percentages. We used student’s t test or the Manfred-Whitney test to compare differences between continuous variables, and the Chi-square or Fisher’s exact test to compare differences between categorical variables, as appropriate. Differences were considered statistically significant at P values less than 0.05. All statistical analysis was performed using SPSS Statistics software version 17.0 (SPSS Inc., Chicago, IL, USA).
Results
Baseline characteristics
During the study period (May 2006 to October 2011), 250 patients underwent TAVI at our centre, all using balloon-expandable Edwards prostheses. A transapical access was used in 60 patients (24%), while 190 (76%) procedures were performed using a transfemoral access. Thus, the current study cohort comprised 190 patients who underwent transfemoral implantation of an Edwards prosthesis: 78 (41.1%) with the SAPIEN prosthesis between May 2006 and September 2009, and 112 (58.9%) with the SAPIEN XT prosthesis between October 2009 and October 2011. Significantly more procedures using the SAPIEN XT versus the SAPIEN prosthesis were performed using a transfemoral approach (112/123 [91.1%] vs 78/127 [61.4%]; P < 0.001; Fig. 2 ).
Most patients underwent TAVI for severe, degenerative symptomatic aortic stenosis, but two patients in the SAPIEN XT group had a degenerated stenotic aortic bioprosthesis. Baseline clinical characteristics are shown in Table 1 . The mean Logistic EuroSCORE was significantly lower in the SAPIEN XT group (18.1 ± 11.0% vs 27.3 ± 11.1%; P < 0.0001). History of myocardial infarction, coronary artery bypass graft and BAV were also significantly less frequent in the SAPIEN XT group. Patients treated with SAPIEN XT had a significantly smaller minimal luminal diameter of the access iliofemoral arteries than those treated with the SAPIEN prosthesis ( Table 1 ). All other variables were comparable between the two groups.
