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1.
Hoda Hatoum Scott Lilly Pablo Maureira Juan Crestanello Lakshmi Prasad Dasi 《The Journal of thoracic and cardiovascular surgery》2021,161(2):565-576.e2
BackgroundThe durability of transcatheter aortic valves (TAVs) remains their greatest disadvantage, given that fixed tissue leaflets are not immune to structural degeneration from calcification and thrombosis. Therefore, a second intervention is necessary, especially given that TAV in low-risk patients has shown noninferior outcomes compared with surgery. This study aimed to assess the hemodynamic and turbulent properties of the flow downstream with different TAV-in-TAV configurations, to offer basic hemodynamic guidance for future interventions when currently implanted valves structurally degrade.MethodsSix TAV-in-TAV configurations were chosen: 23 mm Evolut-in-26 mm Evolut, 23 mm Evolut-in-23 mm SAPIEN 3, 26 mm Evolut-in-26 mm Evolut, 26 mm Evolut-in-23 mm SAPIEN 3, 23 mm SAPIEN3-in-26 mm Evolut, and 23 mm SAPIEN3-in-23 mm SAPIEN 3. Their hemodynamic performance was assessed in a pulse duplicator for 100 cycles. High-speed imaging and particle image velocimetry were performed to assess turbulence. Effective orifice area (EOA), pinwheeling index (PI), and Reynolds shear stress (RSS) were evaluated.ResultsThe largest mean EOA was obtained with 23 mm SAPIEN-in-26 mm Evolut (2.07 ± 0.06 cm2), and the smallest was obtained with 23 mm Evolut-in-23 mm SAPIEN (1.50 ± 0.04 cm2) (P < .001). The highest mean PI was obtained with SAPIEN-in-SAPIEN (26.5 ± 2.00%), and the lowest was obtained with 26 mm Evolut-in-26 mm Evolut (7.5 ± 1.6%) (P < .01). At peak systole, the least detrimental RSS range was obtained with 23 mm Evolut-in-26 mm Evolut (up to ~340 Pa), and the most detrimental RSS range was obtained with 23 mm Evolut-in-SAPIEN (~900 Pa) (P < .01).ConclusionsThis study shows that best hemodynamic parameters are TAV-specific (implanted and to be implanted). In addition, it shows that RSS levels, which are indicative of turbulence levels and associated with blood damage, are 2- to 3-fold higher after TAV-in-TAV. 相似文献
2.
To minimize the incidence of patient-prosthesis mismatch (PPM), we have routinely adopted aortic root enlargement to avoid PPM for patients with small aortic annulus. The aim of this study was to review our strategy of avoiding PPM. The Carpentier-Edwards Perimount (CEP) valves were implanted in 53 patients who were mostly aged over 65 and the St. Jude Medical (SJM) mechanical valves were used in 128 patients aged under 65. A standard 21-mm SJM valve was used in only 3 patients and no 19-mm valves were employed. However, 19-mm CEP valves were used in 12 patients with a small body surface area (1.43 +/- 0.14 m2). Of these, 26 patients (14.4%) who had a small aortic annulus and 24 patients aged under 65 underwent aortic root enlargement. No patient receiving an SJM valve had an projected indexed effective orifice area (EOAI) < or = 0.85 cm2/m2 because of performing aortic valve replacement (AVR) with annular enlargement and only 2 (3.8%) out of 53 patients receiving CEP valves developed PPM. Consequently, the prevalence of PPM was 1.1% in this series. The prevalence of PPM was low in patients over 65 years old with a relatively small body size who received bioprosthetic valves. A pericardial bioprosthesis was considered to be an appropriate valve in older population with regard to avoiding PPM. In patients under 65 years old with a small annulus, the first choice for avoiding PPM is aortic annular enlargement, which may be avoided by high performance mechanical valves with larger EOA. 相似文献
3.
Walther T Möllmann H van Linden A Kempfert J 《Seminars in thoracic and cardiovascular surgery》2011,23(1):55-61
Transcatheter aortic valve implantation (T-AVI) has been introduced into clinical practice to treat high-risk elderly patients with aortic stenosis. T-AVI can be performed by using a retrograde transfemoral (TF), transsubclavian, transaortic, and/or antegrade transapical (TA) approach. For TA-AVI, CE mark approval was granted in 2008 for the Edwards SAPIEN (Edwards Lifesciences, Irvine, CA) prosthesis with the Ascendra delivery system and in 2010 for the second-generation Edwards SAPIEN XT prosthesis and the Ascendra II delivery system, with 23-mm and 26-mm valves. In 2011, CE mark approval has been granted for TA-AVI by using the SAPIEN XT 29-mm prosthesis. Several other devices from different companies (Jenavalve, Jena Valve Inc, Munich, Germany; Embracer, Medtronic Inc, Guilford, CT; Accurate, Symetis Inc, Geneva, Switzerland) have passed "first in man trials" successfully and are being evaluated within multicenter pivotal studies. In this article we will focus on specific aspects of the TA technique for AVI. 相似文献
4.
Dalmau MJ María González-Santos J López-Rodríguez J Bueno M Arribas A Nieto F 《Interactive Cardiovascular and Thoracic Surgery》2007,6(3):345-349
We compared the hemodynamic performance of the Edwards Perimount Magna (EPM) and the Medtronic Mosaic (MM) bioprostheses according to the patient aortic annulus diameter (AAD). Eighty-six patients undergoing aortic valve replacement were prospectively assigned to receive either an EPM-valve (n=43) or an MM-bioprosthesis (n=43). Randomization was performed after measuring the AAD and patients were grouped according to their AAD: <22 mm (n=12), 22-23 mm (n=31) and >23 mm (n=43). Echocardiographic assessment was performed one year postoperatively. The mean AAD (EPM 23.9+/-2.1 mm vs. MM 23.6+/-2.3 mm) and mean valve size implanted (EPM 22.6+/-2.1 mm vs. MM 23.3+/-2.1 mm) were comparable in both groups. The EPM-group showed significantly lower mean gradient (EPM 10.2+/-3.2 mmHg vs. MM 17.1+/-8.2 mmHg) and larger effective orifice area (EOA) (EPM 1.99+/-0.4 cm(2) vs. MM 1.69+/-0.4 cm(2), P<0.0001). The EPM-valve was superior with respect to mean pressure gradient and EOA in all AAD. This difference was statistically significant in AAD of 22-23 mm (EPM 9.6+/-3.0 mmHg vs. MM 18.2+/-8.6 mmHg; EPM 1.82+/-0.3 cm (2) vs. MM 1.51+/-0.2 cm (2)) and >23 mm (EPM 9.9+/-3.1 mmHg vs. MM 14.2+/-5.6 mmHg; EPM 2.18+/-0.4 cm(2) vs. MM 1.94+/-0.5 cm(2)). Patient-prosthesis mismatch was present in 26.8% (MM) vs. 6.9% (EPM) of the patients (P=0.01). When the same AAD is taken as a reference, the EPM-valve was hemodynamically superior to the MM-bioprosthesis. The EPM-prosthesis significantly reduced the incidence of PPM. 相似文献
5.
Mitral replacement: clinical experience with a ball-valve prosthesis. Twenty-five years later.
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The purpose of this report is to review the results of mitral valve replacement since a first report in the Annals of Surgery in 1961, in order to determine the relative importance of new valve designs versus other surgical variables. The continued use of the silastic ball valve in its 1966 configuration (Model 6120), by providing a comparative data base for other new prosthetic valves, allows this analysis. For a valid comparison with the tilting disc (Bjork-Shiley) and the porcine (Hancock and Carpentier-Edwards) valves, only results with the silastic ball valves implanted during comparable time frames should be used. (Formula: see text) Thus, there are no significant differences in the results obtained with the silastic ball valve in time frames comparable to other contemporary valves introduced in the early 1970s. Improved results, therefore, must be non-prosthetic valve related. 相似文献
6.
D'Ancona G Pasic M Buz S Drews T Dreysse S Hetzer R Unbehaun A 《The Annals of thoracic surgery》2012,93(4):e89-e91
We report transcatheter aortic valve implantation (TAVI) for pure aortic valve insufficiency in a patient with an otherwise normal aortic valve and a long-term left ventricular assist device (LVAD). An oversized 29-mm Edwards SAPIEN valve (Edwards Lifesciences, Irvine, CA) was implanted in the 21-mm native aortic valve annulus. Despite the complete absence of aortic calcifications, the prosthesis remained stably anchored inside the annulus. The reported experience demonstrates that TAVI is feasible even in patients with pure aortic valve regurgitation and can be a reasonable option in patients with aortic regurgitation after LVAD implantation. 相似文献
7.
Oda T Fukunaga S Arinaga K Kawano H Chihara S Yokose S Onitsuka S Sakashita H Aoyagi S 《Kyobu geka. The Japanese journal of thoracic surgery》2000,53(4):329-332
To assess the hemodynamic performance of the prosthetic valve in the aortic position, we examined dobutamine-stress echocardiography (DSE) to the patients underwent AVR with CEP valve or SJM valve. In 23 mm size, there were no significant differences between CEP group and SJM group in Peak velocity of the aortic jet (PV), peak pressure gradient (PPG) and effective orifice area (EOA). On the other hand, in 21 mm size, PV and PPG of the CEP group were significantly lower than those of the SJM group after DSE. The EOA of the CEP group was significantly larger than that of the SJM group after DSE. Our results suggest that the hemodynamic function of the CEP valve is superior to that of the SJM valve especially in small aortic annuli. 相似文献
8.
Bruschi G Barosi A Colombo P Botta L Oreglia J De Marco F Paino R Klugmann S Martinelli L 《The Annals of thoracic surgery》2012,93(5):1708-1710
Transcatheter valve implantation into failing surgical mitral bioprosthetic valves have been reported. This strategy avoids performing high-risk repeat cardiac surgery in elderly patients with multiple comorbidities. All these patients have been treated by a transapical approach. We report a case of failing bioprosthetic mitral valve in an 82-year-old woman successfully treated with a 29-mm Edwards SAPIEN balloon expandable bioprosthesis (Edwards Lifesciences, Irvine, CA) with direct left atrial approach through a right anterior thoracotomy. Our experience demonstrates the technical feasibility and safety of this approach. Therefore, mitral valve-in-surgical valve implantation may be a viable treatment alternative in carefully selected patients. 相似文献
9.
Dalmau MJ Maríagonzález-Santos J López-Rodríguez J Bueno M Arribas A 《Interactive Cardiovascular and Thoracic Surgery》2006,5(3):263-267
This study compares the implantation characteristics and the hemodynamic performance of the new Carpentier-Edwards Perimount Magna (CEPM) xenograft with those of the standard Perimount (CEPS) valve in the aortic position. Eighty consecutive patients surviving an aortic valve replacement with either the CEPS valve (n=40) or the CEPM prosthesis (n=40) in the supra-annular position were retrospectively reviewed. One year follow-up was complete and hemodynamic performance assessed by Doppler echocardiography. The mean valve size implanted was 21.3+/-1.7 mm (CEPS) vs. 22.2+/-1.8 mm (CEPM). The average mean pressure gradient was 13.6+/-5.1 mmHg in the CEPS group and 9.6+/-3.3 mmHg in the CEPM group (P<0.0001). Mean and peak gradients were slightly lower and the effective orifice areas (EOA) were larger for the Magna prosthesis than for the comparable standard valves: 19 mm (1.58+/-0.2 vs. 1.28+/-0.1 cm(2)), 21 mm (1.90+/-0.4 vs. 1.69+/-0.4 cm(2)), 23 mm (2.07+/-0.3 vs. 1.86+/-0.3 cm(2)), 25 mm (2.30+/-0.1 vs. 1.89+/-0.5 cm(2)). The average indexed EOA was statistically different between groups (CEPS 0.98+/-0.21 cm(2)/m(2) vs. CEPM 1.20+/-0.25 cm(2)/m(2)). Patient-prosthesis mismatch (indexed EOA相似文献
10.
Kazuyoshi Tanigawa Kiyoyuki Eishi Shiro Yamachika Koji Hashizume Seiichi Tada Kentaro Yamane Kenta Izumi Hideaki Takai Takashi Miura Shun Nakaji 《Annals of thoracic and cardiovascular surgery》2008,14(2):81-87
OBJECTIVE: Short (< or =3 months)- and middle (> or =4 months)-term results of aortic valve replacement (AVR) using 19-mm Carpentier-Edwards Perimount (CEP) bioprosthetic valves and 19-mm Medtronic Mosaic (MM) bioprosthetic valves in patients with small aortic annulus were compared. PATIENTS AND METHODS: At our facility, AVR was performed using bioprostheses in 110 patients from April 1999 to March 2006. Of these patients, 40 were treated using 19-mm CEP (Group C), and 9 using 19-mm MM (Group M). Evaluation by inquiry, physical examination, and echocardiography was performed before, a short term after, and a middle term after surgery, and the effects of AVR were compared. RESULTS: The New York Heart Association (NYHA) functional class grade showed improvements in both groups. The aortic valve peak pressure gradient was 29.8 +/- 10.1 mmHg in Group C and 53.8 +/- 17.3 mmHg in Group M, being higher in Group M, a middle term after surgery. However, the left ventricular mass index (LVMI) showed improvements in both groups compared with the values before surgery, and the left ventricular ejection fraction (LVEF) was maintained. During the middle term after surgery, the frequency of cardiac events showed no significant difference between the two groups. CONCLUSIONS: In the patients treated with 19-mm MM, the aortic valve peak pressure gradient was higher than in those treated with 19-mm CEP, but acceptable improvements in the LVMI, maintenance of the LVEF, and avoidance of cardiac events were observed in both groups. 相似文献
11.
BACKGROUND: The Edwards MIRA mechanical heart valve is designed to optimize hemodynamics, reduce thrombogenicity, and avoid mechanical failure with a special hinge mechanism. The purpose of the study was to investigate the clinical performance and postoperative hemodynamic results of the first European patients receiving Edwards MIRA mechanical heart valves. METHODS: From March 1998 to March 1999 a total of 54 Edwards MIRA valves model numbers 3600 (aortic, n = 44) and 9600 (mitral, n = 10) were implanted in 52 (36 male, 16 female; mean age 61 +/- 10.1 years) consecutive patients undergoing mechanical valve replacement in a prospective study. Follow-up of the patients including physical examination, ECG, blood tests, and Doppler were performed prior to discharge, at 6 months, at 1 year, and at least 2 years postoperatively. RESULTS: Through October 2001 a total of 172 follow-up examinations were completed (51 patients at discharge, 46 patients at 6 months, 43 patients at 12 months, 32 patients at 2 years or beyond). All patients were in NYHA class I and II at the 6-month and 2+-year follow-up. All the patients stated an improved quality of life. Hospital mortality was 1.9%. There were no complications related to anticoagulation. Mean international normalized ratio at 6 months was 3.2 (range 1.9 to 4.3); lactate dehydrogenase was slightly increased with 264 +/- 103 U/L on average (normal value 80 to 240 U/L). No signs of valvular dysfunction or paravalvular leakage were observed. Mean pressure gradients were related to valve diameter: after mitral valve replacement (size 27, 29, 31 mm: 4.8, 3.2, 2.1 mmHg); after aortic valve replacement (size 19, 21, 23, 25 mm: 12.1, 13.1, 9.3, 8.2 mmHg). CONCLUSIONS: These preliminary data suggest good hemodynamic function and a low rate of valve-related complications of the Edwards-MIRA mechanical prosthesis. 相似文献
12.
Bilge Duran Karaduman Asist Prof MD Hüseyin Ayhan Assoc Prof MD Serkan Bulguroğlu MD Telat Keleş prof MD Engin Bozkurt prof MD 《Journal of cardiac surgery》2020,35(12):3592-3595
In recent years, the use of bioprosthetic valve (BPV) has increased significantly with both surgical aortic valve replacement (SAVR) and transcatheter aortic valve implantation (TAVI) due to reasons such as the advantage of not using anticoagulants. Nevertheless, major disadvantage of all BPV is the risk of early structural valve deterioration, leading to valve dysfunction, and requires reoperation, which significantly increases the risk of mortality or major morbidity especially after SAVR. There are a limited number of TAV-in-TAV case reports due to TAVI BPV degeneration. In our knowledge, this is the second report of TAV-in-TAV implantation wherein a previously implanted transfemoral 25-mm nonmetallic Direct Flow SVD valve treated with ViV TAVI via Edwards Sapien XT. 相似文献
13.
Haldenwang PL Strauch JT Hoppe U Müller-Ehmsen J Gawenda M Wahlers T 《The Annals of thoracic surgery》2010,90(6):2035-2037
This case report illustrates our experience with transapical minimally invasive aortic valve implantation in a patient with an extended aneurysm of the thoracoabdominal aorta, who had previously undergone a replacement of the ascending aorta with concomitant aortic valve reconstruction (David procedure). Endovascular stent grafting of the descending aorta was also performed. The implantation of a 23-mm SAPIEN valve (Edwards Lifesciences, Irvine, CA) did not interfere with the existing 26-mm aortic Hemashield prosthesis (Boston Scientific, Natick, MA) or the previously implanted endograft in the descending aortic position. No paravalvular leakage with aortic valve regurgitation, prosthesis instability, or coronary malperfusion was seen after valve implementation. 相似文献
14.
Thomas Walther Volkmar Falk Jrg Kempfert Michael A. Borger Jens Fassl Michael W.A. Chu Gerhard Schuler Friedrich W. Mohr 《European journal of cardio-thoracic surgery》2008,33(6):983-988
OBJECTIVE: To evaluate the feasibility of minimally invasive transapical beating heart aortic valve implantation (TAP-AVI) for high-risk patients with aortic stenosis. METHODS: TAP-AVI was performed via a small anterolateral minithoracotomy in 50 patients from February 2006 to March 2007. A balloon expandable transcatheter xenograft (Edwards SAPIEN THV, Edwards Lifesciences, Irvine, CA, USA) was used. Mean age was 82.4+/-5 years and 39 (78%) were female. Implantation was performed in a hybrid operative theatre using fluoroscopic and echocardiographic visualization. Average EuroSCORE predicted risk for mortality was 27.6+/-12%. Seven (14%) patients were re-operations with patent bypass grafts. RESULTS: TAP-AVI (13 patients 23 mm and 37 patients 26 mm) was successfully performed on the beating heart under temporary rapid ventricular pacing in 47 (94%) patients, and implantation was performed completely off-pump in 34 (68%) patients. Three patients required early conversion; two of them were successfully discharged. There was no prosthesis migration or embolization observed. Echocardiography revealed good hemodynamic function in all and minor incompetence in 23 patients, mostly paravalvular, without any signs of hemolysis. Mortality was due to the overall health condition and non-valve related in all patients. Actuarial survival at 1 month, 6 months and 1 year was 92+/-3.8%, 73.9+/-6.2% and 71.4+/-6.5%, respectively. CONCLUSIONS: Transapical minimally invasive aortic valve implantation is feasible using an off-pump technique. Good results have been achieved in the initial 50 patients, especially when considering the overall high-risk profile of these patients. 相似文献
15.
16.
《The Annals of thoracic surgery》2023,115(3):641-648
BackgroundWe aim to identify the incidence and timing of dysfunction and failure of stented bioprosthetic valves in the pulmonary position in congenital heart disease patients.MethodsA total of 482 congenital heart disease patients underwent 484 stented bioprosthetic pulmonary valve implantations between 2008 and 2018. There were 164 porcine valves (Porcine) and 320 bovine pericardial valves (Pericardial) implanted. Primary endpoints were survival, valve dysfunction, and valve failure.ResultsPericardial valves were implanted in older patients (22.0, interquartile range [IQR] 14-33 vs 16.0, IQR 11-23 years, P < 0.001). Five-year survival (96.7% vs 97.9%) for the Pericardial and Porcine groups, respectively, were similar, P > 0.05. Forty-six (34%) Porcine and 75 (27%) Pericardial group patients met criteria for valve dysfunction at a median echocardiographic follow-up time of 7.43 years (IQR 4.1-9.5 years) and 3.26 years (IQR 1.7-4.7 years), respectively. More Pericardial group patients suffered from at least mild late PR while late median peak gradient was higher in the Porcine group, P < .001 for both. Risk factors for valve dysfunction included decreasing patient age for the entire cohort (hazard ratio [HR] 1.02, 95% confidence interval [CI] 1.00-1.04, P = .015) and lack of anticoagulation at discharge for the Porcine group (HR 3.06, 95% CI 1.03-9.10, P = .044) but not the Pericardial group. Five-year cumulative incidence of dysfunction was 39% for the Pericardial group and 17% for the Porcine group.ConclusionsPorcine stented and bovine pericardial stented valves can be implanted in the pulmonary position in all age groups safely. However, despite similar rates of valve failure, bovine pericardial stented valves have a higher incidence of valve dysfunction at mid-term follow-up. 相似文献
17.
Fukui T Shibata T Sasaki Y Hirai H Motoki M Takahashi Y Suehiro S 《General thoracic and cardiovascular surgery》2007,55(3):91-97
OBJECTIVE: Sorin Bicarbon (SB) and Edwards Mira (EM) valves have an identical mechanical design but different sewing cuffs. The purpose of this retrospective study was to analyze the long-term clinical and echocardiographic outcomes after mitral valve replacement with these two valves in a combined population of patients. METHODS: We retrospectively reviewed records of 73 patients who underwent mitral valve replacement using SB (n = 19) or EM (n = 54) valves. Preoperatively, 49 patients (68.1%) were in New York Heart Association (NYHA) functional class III or IV. Concomitant procedures were performed in 52 patients (71.2%). Early and late postoperative echocardiography was performed in 69 and 57 patients, respectively. RESULTS: Operative mortality was 4.1%, and early morbidity was 9.6%. Overall patient survival at 9 years was 85.1% +/- 4.8%. Actuarial freedom from valve-related death was 95.4% +/- 2.6% at 9 years. As shown by Doppler echocardiography, the early and late mean transprosthetic pressure gradients were 3.4 +/- 1.4 mmHg and 3.8 +/- 2.1 mmHg, respectively. At the end of follow-up, 98.4% of survivors were in NYHA class I or II. CONCLUSION: The Sorin Bicarbon and, Edwards Mira mechanical valves in the mitral position provide satisfactory long-term clinical and echocardiographic performance. 相似文献
18.
Ali N. Azadani Michael Reardon Matheus Simonato Gabriel Aldea Georg Nickenig Ran Kornowski Danny Dvir 《The Journal of thoracic and cardiovascular surgery》2017,153(6):1303-1315.e1
Objective
Transcatheter heart valve implantation in failed aortic bioprostheses (valve-in-valve [ViV]) is an increasingly used therapeutic option for high-risk patients. However, high postprocedural gradients are a significant limitation of aortic ViV. Our objective was to evaluate Medtronic CoreValve Evolut R ViV hemodynamics in relation to the degree of device oversizing and depth of implantation.Methods
Evolut R devices of 23 and 26 mm were implanted within 21-, 23-, and 25-mm Hancock II bioprostheses. Small and gradual changes in implantation depth were attempted. Hemodynamic testing was performed in a pulse duplicator under ISO-5840 standard.Results
A total of 47 bench-testing experiments were performed. The mean gradient of the 26-mm Evolut R in 23- and 25-mm Hancock II was lower than 23-mm Evolut R (P < .001). However, the mean gradient of 26-mm Evolut R in 21-mm Hancock II bioprostheses R (ranging from 21.30 ± 0.23 to 24.30 ± 0.22 mm Hg) was worse than 23-mm Evolut R (ranging from 15.94 ± 0.18 to 20.35 ± 0.16 mm Hg, P < .001). Furthermore, our results suggest that supra-annular implantation of 23-mm and 26-mm Evolut R devices within the bioprostheses can lead to lower gradient and improved leaflet coaptation. Regardless of implantation depth, superior transvalvular gradient is expected with 26-mm Evolut R than 23-mm Evolut R in a nonstenotic Hancock II with a true internal diameter > 17.5 mm.Conclusions
The current comprehensive bench-testing assessment demonstrates the importance of both transcatheter heart valve size and device position for the attainment of optimal hemodynamics during ViV procedures. Additional in vitro testing may be required to develop hemodynamics-based guidelines for device sizing in ViV procedures in degenerated surgical bioprostheses. 相似文献19.
Yue Xuan Danny Dvir Zhongjie Wang Trek Mizoguchi Jian Ye Julius M. Guccione Liang Ge Elaine E. Tseng 《The Journal of thoracic and cardiovascular surgery》2019,157(2):528-536
Objectives
Transcatheter aortic valve replacement has proven successful in treating intermediate-risk, high-risk, and inoperable patients with severe aortic stenosis. Third-generation, balloon-expandable transcatheter aortic valves were developed with an outer sealing skirt to reduce paravalvular leakage. As transcatheter aortic valve replacement use expands, long-term durability questions remain. Valve design influences durability, where regions of increased leaflet stress are vulnerable to early degeneration. However, third-generation transcatheter aortic valve stresses are unknown. Our goals were to determine the stent and leaflet stresses of third-generation, balloon-expandable transcatheter aortic valves.Methods
The commercial 26-mm Edwards SAPIEN 3 valve (Edwards Lifesciences, Inc, Irvine, Calif) underwent high-resolution micro-computed tomography scanning to develop a precise 3-dimensional geometric mesh of the stent and valve. Leaflet material properties were obtained from surgical bioprostheses, and stent material properties were based on cobalt-chromium. Simulations of systemic pressure loading were performed, and stress was calculated using finite element analyses.Results
At diastole, maximum and minimum principal stresses on transcatheter aortic valve leaflets were 2.7 MPa and ?0.47 MPa, respectively. Peak leaflet stresses were observed at upper leaflet commissures, at their connection to the stent. Maximum and minimum principal stresses for the stent were 38.2 MPa and ?44.4 MPa, respectively, at 80 mm Hg and were located just below the commissural stent.Conclusions
Stress analysis of the 26-mm SAPIEN 3 valve using exact geometry from high-resolution scans demonstrated that peak stresses for both transcatheter aortic valve stent and leaflets were present at commissural tips where leaflets were attached. These regions would be most likely to initiate degeneration. The Dacron skirt had minimal effect on stresses on leaflets and stent. 相似文献20.
Remadi JP Marticho P Nzomvuama A Degandt A 《Interactive Cardiovascular and Thoracic Surgery》2003,2(1):80-83
We present a series of 130 consecutive patients operated for aortic valve replacement (AVR) using the standard MIRA prosthesis between January 1999 and March 2001. Most of the patients were male (sex ratio = 2) with a mean age of 61.5 +/- 9.5 years. The prosthesis was implanted using the continuous suture technique. The mean diameter of the implanted prostheses was 23 mm. This series was composed of 66% of isolated AVR. The associated operative procedures were as follows: coronary artery bypass grafting 23%, replacement of the ascending aorta 6%, replacement of the mitral valves 8% and mitral valvuloplasty 3%. A short-term follow-up was performed and echocardiography data at 6 +/- 2.1 months were collected. Operative mortality (<30 days) was 2.32% for the isolated AVR. No structural dysfunction, endocarditis or paraprosthetic leakage were observed. Postoperative ultrasound echography at 6 months revealed a transprosthetic gradient of 14.8 +/- 4.2 mmHg for the mean prosthesis diameter of 23 mm. The Edwards MIRA prosthesis has produced satisfactory and reliable early results. Long-term follow-up will be necessary to confirm these good early results. 相似文献