Author + information
- Received May 2, 2017
- Revision received June 29, 2017
- Accepted July 4, 2017
- Published online August 21, 2017.
- Sung-Han Yoon, MDa,
- Brian K. Whisenant, MDb,
- Sabine Bleiziffer, MDc,
- Victoria Delgado, MDd,
- Niklas Schofer, MDe,
- Lena Eschenbach, MDc,
- Buntaro Fujita, MDf,
- Rahul Sharma, MDa,
- Marco Ancona, MDg,
- Ermela Yzeiraj, MDh,
- Stefano Cannata, MDi,
- Colin Barker, MDj,
- James E. Davies, MDk,
- Antonio H. Frangieh, MDl,
- Florian Deuschl, MDe,
- Tomaz Podlesnikar, MDd,
- Masahiko Asami, MDm,
- Abhijeet Dhoble, MDn,
- Anthony Chyou, MDo,
- Jean-Bernard Masson, MDp,
- Harindra C. Wijeysundera, MDq,
- Daniel J. Blackman, MDr,
- Rajiv Rampat, MBBSs,
- Maurizio Taramasso, MDt,
- Enrique Gutierrez-Ibanes, MDu,
- Tarun Chakravarty, MDa,
- Guiherme F. Attizzani, MDv,
- Tsuyoshi Kaneko, MDw,
- S. Chiu Wong, MDo,
- Horst Sievert, MDx,
- Fabian Nietlispach, MDt,
- David Hildick-Smith, MDs,
- Luis Nombela-Franco, MDy,
- Lenard Conradi, MDz,
- Christian Hengstenberg, MDl,aa,
- Michael J. Reardon, MDj,
- Albert Markus Kasel, MDl,
- Simon Redwood, MDi,
- Antonio Colombo, MDg,
- Saibal Kar, MDa,
- Francesco Maisano, MDt,
- Stephan Windecker, MDm,
- Thomas Pilgrim, MDm,
- Stephan M. Ensminger, MDf,
- Bernard D. Prendergast, MDi,
- Joachim Schofer, MDh,
- Ulrich Schaefer, MDe,
- Jeroen J. Bax, MDd,
- Azeem Latib, MDg and
- Raj R. Makkar, MDa,∗ ()
- aDepartment of Interventional Cardiology, Cedars-Sinai Heart Institute, Los Angeles, California
- bDivision of Cardiovascular Diseases, Intermountain Heart Institute, Salt Lake City, Utah
- cClinic for Cardiovascular Surgery, German Heart Center, Munich, Germany
- dDepartment of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
- eDepartment of General and Interventional Cardiology, University Heart Center, Hamburg, Germany
- fDepartment of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr-University Bochum, Bad Oeynhausen, Germany
- gInterventional Cardiology Unit, EMO-GVM Centro Cuore Columbus & San Raffaele Scientific Institute, Milan, San Raffaele Hospital, Milan, Italy
- hHamburg University Cardiovascular Center, Hamburg, Germany
- iDepartment of Cardiology, St. Thomas’ Hospital, London, United Kingdom
- jHouston Methodist DeBakey Heart and Vascular Center, Houston, Texas
- kDivision of Cardiac and Thoracic Surgery, University of Alabama–Birmingham, Birmingham, Alabama
- lDeutsches Herzzentrum München, Technische Universität München, Munich, Germany
- mDepartment of Cardiology, Bern University Hospital, Bern, Switzerland
- nDepartment of Cardiology, University of Texas Health Science Center, Houston, Texas
- oGreenberg Division of Cardiology, New York–Presbyterian Hospital, Weil Cornell Medicine, New York, New York
- pDivision of Cardiology, Centre Hospitalier de l’université de Montreal, Montreal, Quebec, Canada
- qDivision of Cardiology, Sunnybrook Health Science Centre, Toronto, Ontario, Canada
- rCardiology Department, Leeds Teaching Hospital, Leeds, United Kingdom
- sSussex Cardiac Centre, Brighton and Sussex University Hospitals NHS Trust, Brighton, United Kingdom
- tUniversity Heart Center, University Hospital Zurich, Zurich, Switzerland
- uDepartment of Cardiology, Hospital General Universitario Gregorio Maranon, Madrid, Spain
- vThe Valve and Structural Heart Interventional Center, University Hospitals Case Medical Center, Cleveland, Ohio
- wDivision of Cardiac Surgery, Brigham and Women’s Hospital, Boston, Massachusetts
- xDepartment of Cardiology and Vascular Medicine, CardioVascular Center, Frankfurt, Germany
- yDivision of Cardiology, Hospital Clinicio San Carlos, Madrid, Spain
- zDepartment of Cardiothoracic Surgery, University Heart Center Hamburg, Hamburg, Germany
- aaGerman Center for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany
- ↵∗Address for correspondence:
Dr. Raj R. Makkar, Cedars-Sinai Heart Institute, 8700 Beverly Boulevard, Los Angeles, California 90048.
Background Limited data exist regarding transcatheter mitral valve replacement (TMVR) for patients with failed mitral valve replacement and repair.
Objectives This study sought to evaluate the outcomes of TMVR in patients with failed mitral bioprosthetic valves (valve-in-valve [ViV]) and annuloplasty rings (valve-in-ring [ViR]).
Methods From the TMVR multicenter registry, procedural and clinical outcomes of mitral ViV and ViR were compared according to Mitral Valve Academic Research Consortium criteria.
Results A total of 248 patients with mean Society of Thoracic Surgeons score of 8.9 ± 6.8% underwent TMVR. Transseptal access and the balloon-expandable valve were used in 33.1% and 89.9%, respectively. Compared with 176 patients undergoing ViV, 72 patients undergoing ViR had lower left ventricular ejection fraction (45.6 ± 17.4% vs. 55.3 ± 11.1%; p < 0.001). Overall technical and device success rates were acceptable, at 92.3% and 85.5%, respectively. However, compared with the ViV group, the ViR group had lower technical success (83.3% vs. 96.0%; p = 0.001) due to more frequent second valve implantation (11.1% vs. 2.8%; p = 0.008), and lower device success (76.4% vs. 89.2%; p = 0.009) due to more frequent reintervention (16.7% vs. 7.4%; p = 0.03). Mean mitral valve gradients were similar between groups (6.4 ± 2.3 mm Hg vs. 5.8 ± 2.7 mm Hg; p = 0.17), whereas the ViR group had more frequent post-procedural mitral regurgitation moderate or higher (19.4% vs. 6.8%; p = 0.003). Furthermore, the ViR group had more frequent life-threatening bleeding (8.3% vs. 2.3%; p = 0.03), acute kidney injury (11.1% vs. 4.0%; p = 0.03), and subsequent lower procedural success (58.3% vs. 79.5%; p = 0.001). The 1-year all-cause mortality rate was significantly higher in the ViR group compared with the ViV group (28.7% vs. 12.6%; log-rank test, p = 0.01). On multivariable analysis, failed annuloplasty ring was independently associated with all-cause mortality (hazard ratio: 2.70; 95% confidence interval: 1.34 to 5.43; p = 0.005).
Conclusions The TMVR procedure provided acceptable outcomes in high-risk patients with degenerated bioprostheses or failed annuloplasty rings, but mitral ViR was associated with higher rates of procedural complications and mid-term mortality compared with mitral ViV.
It is estimated that valvular heart disease affects >100 million patients worldwide, which will increase further with the aging population and a subsequent increase in degenerative valve disease. Currently, >40,000 mitral valve replacements are performed annually in the United States, and an analysis of the Society of Thoracic Surgeons (STS) National Database indicated a massive shift from mechanical to bioprosthetic valve replacements (1). Owing to a considerable shift toward bioprosthesis implantation, coupled with frequent repeat operation after mitral valve replacement or repair, it is expected that a growing number of patients will present with degenerated bioprostheses or failed annuloplasty rings (2,3). Although reoperation is considered the standard of care for degenerated bioprostheses or failed annuloplasty rings, these patients are frequently elderly, and repeat cardiac surgery carries significant morbidity and mortality risks (4).
Since the first successful transcatheter aortic valve replacement was introduced by Alain Cribier in 2002 (5), this procedure has already been performed in >250,000 patients worldwide, and it has become the standard treatment in inoperable and high surgical risk patients (6–9). Furthermore, this technology is being increasingly applied to a variety of pathologies such as degenerated bioprostheses (10).
Transcatheter mitral valve replacement (TMVR) for degenerated mitral bioprostheses and failed annuloplasty rings has emerged as a less invasive alternative to repeat cardiac surgery in selected patients deemed at high surgical risk, but the experience of TMVR is limited to small series (11–14). Although previous studies showed the feasibility of TMVR for degenerated mitral bioprostheses and failed annuloplasty rings, the diverse etiologies (stenosis, regurgitation, or a combination of both) and device advancements mandate comprehensive evaluation of clinical outcomes of TMVR with a large cohort. Therefore, we created an international multicenter registry of patients undergoing TMVR.
Study design and patient population
The TMVR registry is an international, multicenter, observational study that enrolled all consecutive patients with mitral degenerated bioprostheses and failed annuloplasty rings undergoing TMVR. The registry was initiated in November 2015, and a total of 25 centers from Europe and North America participated in the registry. Patients were considered candidates for the procedure if they had significant bioprosthetic mitral valve or annuloplasty ring dysfunction (stenosis, regurgitation, or both), with comorbid conditions that would preclude a repeat sternotomy and valve replacement. We collected data retrospectively for cases performed before initiation and prospectively thereafter. This study was approved by the institutional review board of each institution, and all patients provided written informed consent for TMVR and the use of anonymous clinical, procedural, and follow-up data for research. For retrospective analysis of clinically acquired and anonymized data, the institutional review board of some institutions waived the need for written patient informed consent.
Study devices and TMVR procedure
Patients were selected for TMVR at the institutional level after discussions by the multidisciplinary heart team. Device size was selected based on a combination of the manufacturer’s reported internal diameter and true internal diameter as well as computed tomographic and transesophageal echocardiographic measurements (13,15,16). In addition, the valve-in-valve (ViV) software application was used to ensure the proper device size selection. The access site and type of device were determined by the multidisciplinary heart team. All TMVR procedures were conducted in accordance with local guidelines using standard techniques via transseptal, transapical, or transatrial access, and the balloon-expandable transcatheter valves (Sapien, Sapien XT, and Sapien 3 [Edwards Lifesciences, Irvine, California], and Melody [Medtronic, Minneapolis, Minnesota]) or other transcatheter valves (Lotus [Boston Scientific, Natick, Massachusetts], and Direct Flow [Direct Flow Medical, Santa Rosa, California]) were implanted (17–22).
Endpoints and definitions
The primary endpoints of the present study were all-cause mortality rates at 30 days and 1 year. Secondary endpoints were technical, device, and procedural success and other 30-day major clinical endpoints defined according to the Mitral Valve Academic Research Consortium (MVARC) criteria (23,24). Technical success was determined at exit from the catheterization/operating room and defined as a procedure meeting all of the following: absence of procedural mortality; successful access, delivery, and retrieval of the device delivery system; successful deployment and correct positioning of the first intended device; and freedom from emergency surgery or reintervention related to the device or access procedure. Device success was assessed at 30 days and at all later post-procedural intervals. This success was defined as follows: absence of procedural mortality or stroke; proper placement and positioning of the device; freedom from unplanned surgical or interventional procedures related to the device or access procedure continued intended safety and performance of the device, including: 1) no evidence of structural or functional failure; 2) no specific device-related technical failure issues and complications; and 3) reduction of mitral regurgitation to acceptable levels without significant mitral stenosis and with no greater than moderate (2+) paravalvular mitral regurgitation (and without associated hemolysis). Although the original MVARC criteria defined significant mitral stenosis as a post-procedural transmitral gradient ≥5 mm Hg or an effective orifice area <1.5 cm2, a post-procedural transmitral gradient ≥5 mm Hg was relatively common in post-mitral valve replacement and repair (25). Therefore, for the purpose of the present study, we used modified criteria for significant mitral stenosis defined as a transmitral gradient ≥10 mm Hg and/or an effective orifice area ≤1.0 cm2 according to the American Society of Echocardiography guidelines (26). Procedural success was determined at 30 days, and it was defined as a procedure that has achieved device success without major clinical complications, including death, stroke, life-threatening/fatal bleeding, major vascular complications, stage 2 or 3 acute kidney injury, severe congestive heart failure, valve-related dysfunction, or other complications requiring surgery or repeat intervention.
Other endpoints included procedure- and device-related complications, as well as echocardiographic assessment of the valve and cardiac function immediately after the procedure and 30 days’ post-procedurally. All echocardiographic, procedural, and clinical data were assessed at each institution according to MVARC criteria (23,24). The severity of regurgitation was qualitatively assessed and graded by using transthoracic echocardiography at each institution according to established guidelines and MVARC criteria (23,24,26).
Data collection included baseline clinical, laboratory, echocardiographic, and computed tomographic data, as well as procedural data, antithrombotic treatment, and clinical follow-up data, at pre-specified time points (1, 6, and 12 months and yearly thereafter). Follow-up was obtained by clinical visits and/or through telephone contacts. Referring cardiologists, general practitioners, and patients were contacted whenever necessary for further information. All data provided by each institution were anonymized and centrally collected, and all inconsistencies were resolved directly with local investigators and on-site data monitoring.
Patients were stratified according to whether they had TMVR for failed mitral bioprosthetic valves or annuloplasty rings. Continuous variables are presented as mean ± SD and were compared by using the Student t test or Mann-Whitney U test. Categorical variables are presented as counts or percentages and were compared by using the chi-square or Fisher exact test. Cumulative rates of death were calculated by using the Kaplan-Meier survival analysis, and the log-rank test was used for comparisons across the groups. Univariable Cox regression models were used to evaluate potential predictors of all-cause mortality at 1 year. Statistically significant variables with a p value <0.10 by univariable analysis were included in the multivariable model. The final model was determined by backward elimination procedures with a threshold p value <0.10. The proportional hazards assumption was confirmed by examination of log (–log [survival]) curves and by testing of partial (Schoenfeld) residuals, and no relevant violations were found. The estimated hazard ratio (HR) with 95% confidence interval (CI) was provided by the Cox model. All statistical analyses were performed by using SPSS version 24.0 (IBM SPSS Statistics [IBM Corporation, Armonk, New York]). A 2-sided p value <0.05 was considered to be statistically significant.
A total of 248 patients with previous mitral valve surgery were treated with TMVR across 25 participating centers between February 2009 and February 2017. The baseline characteristics of the study population are shown in Table 1. Of the study population, 176 patients (71.0%) had TMVR for degenerated mitral bioprosthetic valves (ViV), and 72 patients (29.0%) had TMVR for failed annuloplasty rings (valve-in-ring [ViR]). In the overall cohort, the majority of patients were female (56.9%), with a mean age of 72.5 years, and had a high surgical risk with a mean STS score of 8.9 ± 6.8% and a logistic European System for Cardiac Operative Risk Evaluation of 26.9 ± 15.8%. Surgical risk scores were similar between the ViV and ViR groups (STS score: 9.3 ± 7.0% vs. 8.1 ± 6.2%; p = 0.24; logistic European System for Cardiac Operative Risk Evaluation: 26.2 ± 15.6 vs. 28.2 ± 16.2; p = 0.44). The ViV group was more likely to be female (63.1% vs. 41.7%; p = 0.002) and had more frequent previous cerebrovascular accidents (21.0% vs. 5.6%; p = 0.003) compared with the ViR group. However, the ViR group had more extensive coronary artery disease (50.0% vs. 32.4%; p = 0.009) with more frequent previous myocardial infarction (30.6% vs. 9.1%; p < 0.001), previous percutaneous coronary intervention (22.2% vs. 11.9%; p = 0.04), previous coronary artery bypass graft surgery (37.5% vs. 22.2%; p = 0.013), and lower left ventricular ejection fraction (45.6 ± 17.4% vs. 55.3 ± 11.1%; p < 0.001). In terms of failure mode, predominant mitral regurgitation was more frequent in the ViR group compared with the ViV group (77.8% vs. 36.4%; p < 0.001), whereas mitral stenosis was more frequent in the ViV group (35.8% vs. 4.2%; p < 0.001).
Patients treated with TMVR had a variety of mitral bioprostheses and annuloplasty rings (Online Table 1). The median label size and internal diameter of mitral bioprostheses were 29 mm and 27 mm, respectively. In terms of property of annuloplasty rings, rigid, semi-rigid, and flexible rings were used in 14 patients (19.4%), 41 patients (56.9%), and 9 patients (12.5%). Complete annuloplasty rings were used in 52 patients (72.2%), and the median commissure-to-commissure distance of ring was 29 mm.
The procedural data are summarized in Table 2. With respect to access site, the majority of patients were treated via transapical access (66.5%), and the remaining patients were treated via transseptal (33.1%) and transatrial (0.4%) access. Among patients treated with transseptal access, an apical rail technique with wire externalization from venous access to apical site was used in 4 patients (4.9%). The most frequently used transcatheter valves were the balloon-expandable valves (89.9%), followed by the Lotus (5.6%) and the Direct Flow (4.4%). Balloon pre-dilatation was performed in 8.5%, with no significant difference between the ViV and ViR groups, whereas balloon post-dilatation was more frequently performed in the ViR group compared with the ViV group (12.5% vs. 4.0%; p = 0.013).
Procedural and clinical outcomes
The procedural outcomes of the study population are summarized in Table 3. Composite endpoints of technical, device, and procedural success were assessed according to MVARC criteria (Online Table 2). In the overall group, procedure-related death, conversion to conventional surgery, left ventricular outflow tract (LVOT) obstruction, valve embolization, and left ventricular perforation were observed in 3 (1.2%), 5 (2.0%), 8 (3.2%), 4 (1.6%), and 1 patient (0.4%), respectively. Technical success was achieved in the majority of patients (92.3%). However, the ViR group had a significantly lower technical success rate compared with the ViV group (83.3% vs. 96.0%; p = 0.001) due to more frequent second valve implantation (11.1% vs. 2.8%; p = 0.008). Reintervention was required in 25 patients (10.1%) and was more frequent in the ViR group compared with the ViV group (16.7% vs. 7.4%; p = 0.03). Paravalvular leak closure tended to be more frequent in the ViR group compared with the ViV group (6.9% vs. 2.3%; p = 0.07), whereas there were no significant differences between the ViV and ViR groups in atrial septal defect closure (4.0% vs. 4.2%; p = 0.95) and surgical mitral replacement (1.1% vs. 2.8%; p = 0.58).
With respect to echocardiographic findings, post-procedural left ventricular ejection fraction was lower in the ViR group compared with the ViV group (44.1 ± 15.4% vs. 52.8 ± 12.0%; p < 0.001), whereas there were no significant differences between the 2 groups in mitral valve mean gradient (5.8 ± 2.7 mm Hg vs. 6.4 ± 2.3 mm Hg; p = 0.17) and mitral valve area (2.1 ± 0.8 cm2 vs. 2.0 ± 0.6 cm2; p = 0.37). However, the incidence of moderate or greater mitral regurgitation at post-procedure was significantly higher in the ViR group compared with the ViV group (19.4% vs. 6.8%; p = 0.003), which remained significantly higher at 30 days even after the closure of paravalvular leakage (13.6% vs. 3.6%; p = 0.005) (Figure 1). Among 9 patients (4 patients in the ViV group and 5 patients in the ViR group) who received paravalvular leak closure after TMVR for the correction of significant mitral regurgitation, 7 patients (77.8%) showed improvement of mitral regurgitation to less than moderate (ViV: 75.0%; ViR: 80.0%; p > 0.99). In the ViR group, mitral regurgitation moderate or higher at 30 days was more frequent in patients with flexible rings compared with those with semi-rigid rings (44.4% vs. 10.8%; p = 0.02) (Online Figure 1). It is noteworthy that there was no patient who had significant mitral stenosis with a transmitral mean gradient ≥10 mm Hg and mitral valve area ≤1.0 cm2. Due to more frequent reintervention and lower technical success rate, the device success rate was significantly lower in the ViR group compared with the ViV group (76.4% vs. 89.2%; p = 0.009).
Clinical outcomes are summarized in Table 4. There were no significant differences between the ViV and ViR groups in 30-day all-cause mortality (5.7% vs. 8.3%; p = 0.44), stroke (2.3% vs. 0%; p = 0.33), major or extensive bleeding (6.3% vs. 4.2%; p = 0.52), or major vascular complication (1.7% vs. 1.4%; p > 0.99). However, the ViR group had more frequent life-threatening or fatal bleeding (8.3% vs. 2.3%; p = 0.03) and stage 2 or 3 acute kidney injury (11.1% vs. 4.0%; p = 0.03) compared with the ViV group, which resulted in a significantly lower procedural success rate in the ViR group (58.3% vs. 79.5%; p = 0.001).
Impact of access site and learning curve
With stratification according to whether patients were treated via transseptal or transapical access, procedural and clinical outcomes are shown in Online Figure 2. There were no significant differences between transseptal and transapical access in procedural-related death, conversion to surgery, LVOT obstruction, second valve implantation, and technical success. However, patients in the transseptal group required more frequent closure of an iatrogenic atrial septal defect compared with the transapical group (12.2% vs. 0.0%; p < 0.001), which resulted in lower device success rate (78.0% vs. 89.1%; p = 0.02). Nevertheless, there were no significant differences between the 2 groups in clinical outcomes at 30 days and procedural success. Given that the median number of TMVR procedures at each institution was 8, patients were divided into the early experience group (the first 7 cases) and the late experience group (the 8th case and thereafter). There were no significant differences between the early and late experience groups in terms of procedural and 30-day clinical outcomes for the overall cohort as well as the transseptal cohort (Online Figures 3 and 4).
Over a median follow-up period of 220 days (interquartile range, 40 to 560 days), 48 patients died in the overall cohort (28 patients in the ViV group and 20 patients in the ViR group). The cumulative event rate for all-cause mortality at the 1-year follow-up was 16.9%, with significantly higher all-cause 1-year mortality in the ViR group compared with the ViV group (28.7% vs. 12.6%; log-rank test, p = 0.01) (Central Illustration). There were no significant differences between the transseptal and transapical access groups in 1-year all-cause mortality (16.2% vs. 17.4%; log-rank test, p = 0.74) (Figure 2). On univariable analysis, the factors associated with 1-year all-cause mortality were age, predominant mitral regurgitation at baseline, left ventricular ejection fraction, failed annuloplasty ring, and moderate or greater post-procedural mitral regurgitation. After adjustment with multivariable analysis, age (HR: 1.04; 95% CI: 1.00 to 1.08; p = 0.03) and failed annuloplasty ring (HR: 2.70; 95% CI: 1.34 to 5.43; p = 0.005) were independently associated with 1-year all-cause mortality (Table 5).
Antithrombotic therapy and clinical thrombosis
Information regarding anticoagulation and post-procedural thrombosis was available in 236 patients (95.2%: 166 patients in the ViV group and 70 patients in the ViR group). Among them, 152 patients (64.4%) received anticoagulation (warfarin or direct oral anticoagulant agents) for at least 3 months after TMVR, and 84 patients (35.6%) received antiplatelet agents only after TMVR (Figure 3). Among patients receiving only antiplatelet agents, 3 patients presented with symptomatic mitral valve thrombosis within 1 month after TMVR (3.6%), whereas no patients had clinical mitral valve thrombosis when receiving anticoagulant agents (p = 0.04).
The present study is, to the best of our knowledge, the first large-scale study that evaluated the safety, efficacy, and clinical outcomes of TMVR in patients with degenerated mitral bioprostheses and failed annuloplasty rings. The major findings of the present study are as follows: 1) in the overall cohort, the procedural and clinical outcomes of TMVR for patients with degenerated mitral bioprostheses and failed annuloplasty rings were acceptable despite high surgical risk with multiple comorbidities; 2) compared with patients with degenerated mitral bioprostheses, TMVR for patients with failed annuloplasty rings was associated with lower rates of technical, device, and procedural success; and 3) the cumulative event rates for all-cause mortality after TMVR at the 1-year follow-up were higher in patients with failed annuloplasty rings compared with those with degenerated mitral bioprostheses.
Recently, several studies reported the acceptable clinical outcomes of TMVR for patients with degenerated bioprosthesis or failed annuloplasty rings (11,27–29). However, these studies were limited in sample size, type of previous mitral valve surgery (replacement or repair), and access site. A substantial portion of patients required reoperation after either mitral valve replacement or repair (30), but reoperation after mitral valve surgery is associated with increased perioperative mortality and morbidity in elderly patients (4), which leads to a large number of undertreated patients with degenerated mitral bioprostheses and dysfunctional annuloplasty rings. Therefore, comprehensive understanding of outcomes of TMVR for both degenerated bioprosthesis and failed annuloplasty ring is essential. Furthermore, advancements in transcatheter valves with smaller profiles have enabled easier transseptal access; this approach needs further assessment of its efficacy and safety compared with the conventional transapical approach.
In the present study, patients with degenerated mitral bioprosthesis and failed annuloplasty rings both exhibited high surgical risk, with mean STS scores of 9.3% and 8.1%, respectively. However, there were significant differences in baseline characteristics: female subjects and previous cerebrovascular accidents were more frequent in the ViV group; and the ViR group had more frequent predominant mitral regurgitation with extensive coronary artery disease and lower left ventricular ejection fraction compared with the ViV group, which may reflect the recurrence and progression of ischemic mitral regurgitation after mitral valve repair with ring annuloplasty. In the present study, high technical and device success rates of mitral ViV were observed in a variety of types and sizes of mitral bioprostheses as well as mode of failure. Although anatomical challenges with the transseptal approach or more invasive transapical approach are required in TMVR, the accumulated experience and evidence from “aortic” ViV may help to select appropriate device size and accurate deployment of transcatheter valves. However, compared with mitral ViV, mitral ViR was associated with lower technical, device, and procedure success.
The challenges of the mitral ViR procedure may be attributable to several factors: 1) initially elliptical annuloplasty rings need to become circular during the TMVR procedure, but the various degrees of rigidity of annuloplasty rings and the absence of definite recommendations regarding the appropriate size and type of transcatheter devices led to difficulties in predicting the ring deformability and resulted in more frequent mitral regurgitation; and 2) the optimal implantation of a transcatheter valve is limited due to the existence of native anterior mitral leaflet and insufficient fixation with annuloplasty rings, resulting in more frequent need for second valve implantation or LVOT obstruction with too low deployment in the left ventricular cavity.
The mitral ViV was initially performed via a transseptal and transatrial approach by Webb et al. (31), but difficulties in achieving a coaxial alignment of the transcatheter valve and mitral bioprosthesis has established the transapical approach as a more feasible route thereafter (13). Nevertheless, the present study showed that the procedural and clinical outcomes of the transseptal approach were comparable to those of the transapical approach, except for the more frequent requirement of closure of an iatrogenic atrial septal defect. The challenges in achieving coaxiality and stabilization of a balloon-expandable valve with transseptal access may be overcome by the optimized transseptal puncture guided by intraoperative transesophageal echocardiography (16). Although the present study did not show improved outcomes with increased experience, the impact of a less invasive procedure on clinical outcomes should be evaluated in a larger cohort with longer term follow-up.
Mid- and long-term mortality may be affected by procedural complications in combination with baseline comorbidities and underlying mitral valve disease. The higher mid-term mortality of ViR compared with ViV warrants careful selection of patients for a ViR procedure. LVOT obstruction was a potentially devastating complication, and its prediction still poses a challenge (32,33). In addition, the need for second valve implantation in the mitral position raises the concern for increase of transmitral pressure gradient or risk of intra-atrial thrombosis (25,34). Furthermore, the nature of the underlying mitral valve disease could affect the long-term outcomes. Nevertheless, given the early experience and lack of knowledge and evidence in TMVR fields, further improvements in procedural and consequently better clinical outcomes of TMVR are awaited in the future. These improvements will be achieved through comprehensive understanding of the TMVR procedure, accumulation of experience and appropriate technique for the successful procedure, establishment of guidelines for size and type of transcatheter valves, and technical device advancement.
The risk of thrombosis has been increasingly recognized after transcatheter valve replacement in the setting of ViV implantations (32), particularly in the mitral position (33,34). According to the recently updated 2014 American Heart Association/American College of Cardiology guidelines, anticoagulation therapy with warfarin is reasonable for the first 3 months after surgical bioprosthetic mitral valve replacement as well as transcatheter “aortic” valve replacement (Class IIa) (35). However, limited data exist regarding antithrombotic treatment for ViV procedures. In the present study, the absence of anticoagulation was associated with early mitral valve thrombosis, which may be attributable to low transvalvular pressure. The present results do not allow for provision of recommendations on the duration of anticoagulant treatment after TMVR. Future studies are awaited to assess the optimal duration of anticoagulation treatment after TMVR.
First, this study had the inherent limitations of an observational study without center-independent adjunction of adverse events and an independent core laboratory to assess mitral regurgitation. In addition, the outcomes in this study could differ from those in “real- world” practice due to potential selection biases. Moreover, device selection was not randomized but left at the operator’s discretion, and patient selection as well as operator experience may have affected the observed outcomes.
The TMVR procedure provided acceptable outcomes in high-risk patients with degenerated bioprostheses or failed annuloplasty rings, but mitral ViR was associated with higher rates of procedural complications and mid-term mortality compared with mitral ViV.
COMPETENCY IN PATIENT CARE AND PROCEDURAL SKILLS: TMVR provided acceptable outcomes in high-risk patients with degenerated bioprostheses or annuloplasty rings, but ViR procedures were associated with higher rates of complications and mid-term mortality than ViV replacement.
TRANSLATIONAL OUTLOOK: Future studies should evaluate the long-term outcomes and optimal antithrombotic treatment of patients undergoing TMVR for degenerated bioprostheses or failed annuloplasty rings.
For supplemental tables and figures, please see the online version of this paper.
The Department of Cardiology at the Leiden University Medical Center received research grants from Edwards Lifesciences, Biotronik, Medtronic, and Boston Scientific. Dr. Whisenant has served as a consultant for Edwards Lifesciences and Boston Scientific. Dr. Bleiziffer has served as a consultant to Medtronic; as a proctor for Medtronic and JenaValve; and has received travel compensation from Edwards Lifesciences, Medtronic, and Johnson & Johnson. Dr. Delgado has received speaking fees from Abbott Vascular. Dr. Barker is on the advisory board of Medtronic and Boston Scientific; and on the speakers bureau of Abbott Vascular. Dr. Sharma has served as a proctor for Edwards Lifesciences. Dr. Masson has served as a consultant for Edwards Lifesciences. Dr. Wijeysundera has received research grants from Edwards Lifesciences and Medtronic. Drs. Blackman and Smith have served as proctors for Medtronic and Boston Scientific. Dr. Taramasso has served as a consultant for St. Jude Medical. Dr. Attizzani has served as a proctor for Edwards Lifesciences and Medtronic; on the speakers bureau for Medtronic and Abbott Vascular; and as a consultant to St. Jude Medical. Dr. Kaneko is a consultant for Edwards Lifesciences. Dr. Nietlispach has served as a consultant for Edwards Lifesciences, St. Jude Medical, Direct Flow Medical, and Medtronic. Dr. Hengstenberg has served as a proctor for Edwards Lifesciences and Symetis; has received travel compensation from Edwards Lifesciences, Medtronic, and Symetis; and has received speaker honoraria from Edwards Lifesciences and Symetis. Dr. Kasel has served as a consultant for and received research support from Edwards Lifesciences. Drs. Prendergast and Redwood have received speaker fees from Edwards Lifesciences, Boston Scientific, and Symetis. Dr. Kar has received research grants and consulting fees from Abbott Vascular and St. Jude Medical. Dr. Maisano has served as a consultant for Edwards Lifesciences, Medtronic, St. Jude Medical, Abbott Vascular, and Veltech; and has received royalties from Edwards Lifesciences. Dr. Windecker has received research grants to the institution from Abbott, Biotronik, Boston Scientific, Edwards Lifesciences, Medtronic, The Medicines Company, and St. Jude Medical; and has received speaker fees from AstraZeneca, Eli Lilly, Abbott, Biotronik, Boston Scientific, Bayer, and Biosensors. Dr. Pilgrim has received speaker fees from Biotronik and Medtronic; and has received travel honoraria from Biotronik and Edwards Lifesciences. Dr. Ensminger has served as a proctor for JenaValve; has received speaker honoraria from Edwards Lifesciences, JenaValve, and Symetis; and has received travel compensation from Edwards Lifesciences, JenaValve, and Symetis. Dr. Wood has received grant support or research contracts from Boston Scientific; and honoraria from Edwards Lifesciences. Dr. Schofer has received travel support from Edwards Lifesciences and Boston Scientific. Dr. Latib has served on the Medtronic advisory board; and has served as a consultant for Direct Flow Medical. Dr. Makkar has received grants from Edwards Lifesciences; and personal fees from St. Jude Medical and Medtronic. All other authors reported that they have no relationship relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- confidence interval
- hazard ratio
- left ventricular outflow tract
- Mitral Valve Academic Research Consortium
- Society of Thoracic Surgeons
- transcatheter mitral valve replacement
- Received May 2, 2017.
- Revision received June 29, 2017.
- Accepted July 4, 2017.
- 2017 American College of Cardiology Foundation
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