Author + information
- Received December 9, 2015
- Revision received January 29, 2016
- Accepted February 25, 2016
- Published online June 13, 2016.
- Mackram F. Eleid, MDa,
- Allison K. Cabalka, MDa,
- Matthew R. Williams, MDb,
- Brian K. Whisenant, MDc,
- Oluseun O. Alli, MDd,
- Neil Fam, MDe,
- Peter M. Pollak, MDa,
- Firas Barrow, MDb,
- Joseph F. Malouf, MDa,
- Rick A. Nishimura, MDa,
- Lyle D. Joyce, MD, PhDa,
- Joseph A. Dearani, MDa and
- Charanjit S. Rihal, MD, MBAa,∗ ()
- aDepartment of Cardiovascular Diseases and Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota
- bDivision of Cardiovascular Diseases, New York University Medical Center, New York, New York
- cDivision of Cardiovascular Diseases, Intermountain Heart Institute, Salt Lake City, Utah
- dDivision of Cardiovascular Diseases, University of Alabama, Birmingham, Alabama
- eDivision of Cardiovascular Diseases, St. Michael’s Hospital, Toronto, Ontario, Canada
- ↵∗Reprint requests and correspondence:
Dr. Charanjit S. Rihal, Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, Minnesota 55905.
Objectives This study sought to examine the feasibility, safety, and intermediate-term outcomes in patients undergoing percutaneous transvenous transcatheter mitral valve implantation in failed bioprosthesis, ring annuloplasty, and calcific mitral stenosis.
Background Surgical mitral valve replacement in patients with previous surgery or severe mitral annular calcification (MAC) is often associated with high or prohibitive risk.
Methods Percutaneous transfemoral antegrade transseptal implantation of Edwards SAPIEN prosthesis (Edwards Lifesciences, Irvine, California) was performed in 48 patients with degenerated mitral bioprosthesis (n = 33), previous ring annuloplasty (n = 9), and severe MAC (n = 6).
Results The mean Society of Thoracic Surgeons risk score was 13.2 ± 7.4% with a mean age 76 ± 11 years. Acute procedural success was achieved in 42 of 48 patients (88%) in the overall group and 31 of 33 (94%) in the failed bioprosthetic mitral valve group and success rate of 11 of 15 (73%) in patients with failed annuloplasty rings and MAC. After successful procedure, no patients had > mild residual mitral prosthetic or periprosthetic regurgitation; mean transvalvular gradients were 6 ± 2.5 mm Hg. Thirty-day survival free of death and cardiovascular surgery was 85% in the overall group and 91% in the failed bioprosthetic mitral valve subgroup.
Conclusions Transfemoral percutaneous transvenous mitral valve implantation in high-risk patients with degenerated bioprosthesis is safe, effective, and associated with rapid improvement in hemodynamics, short length of stays, and improved functional status. Percutaneous mitral valve implantation in patients with failed annuloplasty rings and severe MAC is a promising therapy with significant short-term morbidity and mortality that requires further study.
Repeat operation in the first 10 years following mitral valve replacement or repair is required in up to 35% of patients (1,2). Redo mitral valve surgery can be associated with high mortality, particularly in patients with severe medical comorbidities. Nonrheumatic mitral stenosis due to mitral annular calcification (MAC) can be treated with mitral valve replacement, but presents unique challenges and carries a higher procedural mortality (3,4). Transcatheter valve-in-valve implantation is a promising therapy for such patients, with emerging evidence suggesting excellent feasibility of this approach (5–7). Although a less invasive treatment, transcatheter mitral valve-in-valve procedures pose several challenges including lack of direct visualization of the valve during deployment and lack of direct fixation of the valve prosthesis using sutures. As such, accurate pre-procedural planning taking into account appropriate access site and valve size is critical in an often elderly and frail population.
We have previously reported the feasibility of percutaneous transvenous transcatheter mitral and tricuspid valve-in-valve treatment using the Melody valve (Medtronic, Minneapolis, Minnesota) (6). However, the bovine jugular venous Melody valve designed for pulmonic implantation may have less favorable long-term durability compared to surgical valves when exposed to the higher closing pressure and hemodynamic stress imposed in the mitral position. Furthermore, the Melody valve outer diameter of 24 mm may limit application to larger size bioprosthetic valves, especially when the primary mechanism of valve failure is regurgitation without stenosis. We sought to evaluate the immediate and midterm outcomes of percutaneous antegrade transvenous transseptal mitral valve implantation using the recently commercially available SAPIEN valve (Edwards Lifesciences, Irvine, California) in patients with failed mitral bioprosthesis, ring annuloplasty, and severe MAC.
From January 2014 through December 2015, 29 patients underwent percutaneous transvenous transseptal implantation of the SAPIEN, SAPIEN XT, or SAPIEN 3 valve into the mitral position at Mayo Clinic (Rochester, Minnesota), 10 at New York University Medical Center (New York, New York), 4 at Intermountain Heart Institute (Salt Lake City, Utah), 3 at University of Alabama (Birmingham, Alabama), and 2 at St. Michael’s Hospital (Toronto, Canada). Patients were considered candidates for the procedure if they had significant bioprosthetic mitral valve or annuloplasty ring dysfunction (either stenosis, regurgitation, or both), or severe mitral stenosis due to MAC, with comorbid conditions that would preclude a repeat sternotomy and valve replacement. All patients were seen and assessed by a cardiovascular surgeon prior to proceeding with percutaneous valve therapy. All patients received detailed instruction on potential risks of the procedure and the off-label use of the SAPIEN valve. Alternatives, including repeat open surgery and medical therapy, were carefully discussed. All patients provided informed consent for the procedure. Patients were counseled about the need for long-term anticoagulation with warfarin post-valve implantation (in the absence of contraindications). All procedures were performed electively with the exception of 2 urgent mitral valve implantations. Four procedures were performed using planned venoarterial extracorporeal membrane oxygenation (ECMO); the remaining were performed without hemodynamic support devices. This retrospective study was approved by the Mayo Clinic Institutional Review Board.
In most cases, transcatheter valve size was selected based on a combination of the manufacturer’s reported internal dimension and true internal dimension as well as computed tomography (CT)–derived and transesophageal echocardiography (TEE)-derived measurements (8). The valve-in-valve app was consulted for each case to ensure proper valve size selection (Bapat V, Valve in Valve Mitral app, http://www.ubqo.com/vivmitral). We typically added an additional 1 to 2 ml of additional volume to the deployment balloon and determined the amount of volume based on the visual appearance of the valve, aiming to achieve mild flaring of the ends of the valve stent on the ventricular and atrial sides. For patients with calcific mitral stenosis, 3D CT evaluation of the mitral annulus and leaflets was essential to determine the presence of adequate calcification of at least 75% of the circumference of the valve in all 4 quadrants to facilitate transcatheter valve anchoring. Different valve sizes were overlayed using a 3D CT model (and in some cases a printed model was created) to determine optimal valve size that would result in 5% to 10% oversizing (Online Figure 1). In emergent cases and in cases of SAPIEN implantation into native severe MAC, consideration was given to the use of ECMO support during the procedure due to higher risk of complications including hemodynamic instability, left ventricular (LV) perforation and LV outflow tract obstruction. The decision to use ECMO was made on a case-by-case basis by the treating physicians.
Mitral valve-in-valve procedure
The mitral valve-in-valve procedure was performed in the cardiac catheterization laboratory (Figure 1) using an adaptation based on our recently reported technique (9). Patients were placed under general endotracheal anesthesia. Intraprocedural imaging was performed with TEE (Figure 2). Two Perclose ProGlide devices (Abbott Vascular, Santa Clara, California) were deployed in a pre-close fashion in the right common femoral vein and the Edwards E-Sheath was introduced. A 5-F pacing catheter was advanced into the right ventricle via the femoral vein for rapid pacing during valve deployment. Transseptal puncture was performed using standard techniques under TEE guidance (Figure 2). The atrial septum was sequentially dilated with a 14-F dilator, followed by a 10 to 14 mm Mustang (Boston Scientific, Marlborough, Massachusetts) or 15 mm Tyshak (Braun, Bethlehem, Pennsylvania) balloon depending on the size of SAPIEN valve being used. An 8.5-F medium curve Agilis sheath (St. Jude Medical, St. Paul, Minnesota) or 9-F Dexterity steerable introducer (Spirus Medical, West Bridgewater, Washington) was placed in the left atrium over an Inoue wire (Toray Industries, Tokyo, Japan). Unfractionated heparin (200 U/kg) was administered to ensure adequate systemic anticoagulation, and the activated clotting time was monitored regularly to maintain a level >300 s.
Antegrade transseptal approach with LV anchor wire
The majority (n = 45) of cases were performed without obtaining transapical access in order to avoid complications associated with transapical access and to simplify procedural technique (Figure 3). In these cases, after dilatation of the atrial septum and introduction of the Agilis or Dexterity sheath, a stiff-angled Glidewire (Terumo, Somerset, New Jersey) was advanced into the LV over a 6-F multipurpose guiding catheter. Once the multipurpose catheter was advanced into the ventricle, a Lunderquist extra-stiff wire with double curve (Cook Medical, Bloomington, Indiana) was carefully advanced into the LV, using the support from the Agilis sheath. During the second half of our experience we transitioned from using an Agilis sheath to a Dexterity sheath to enhance support for stiff wire delivery into the LV, and to using a small-curve Safari wire (Boston Scientific, Marlborough, Massachusetts) in place of the Lunderquist wire to reduce the risk of trauma to the LV. The wire was then used as the LV anchor wire rail for the antegrade transseptal delivery of the SAPIEN valve.
The internal diameter of the dysfunctional valve was measured with TEE and/or cardiac CT. Balloon sizing was only performed in select cases where it was not apparent whether the internal diameter of the existing bioprosthetic valve or ring would adequately anchor the SAPIEN valve. In all cases, the SAPIEN valve was mounted onto the delivery catheter with skirt oriented towards the delivery system handle (atrial side) (Figure 4) and delivered antegrade via the right femoral vein, across the atrial septum, and into the dysfunctional prosthesis over the arteriovenous rail. Counterclockwise rotation and a moderate degree of catheter flexion were used to advance the delivery catheter with mounted valve across the atrial septostomy. The valve was carefully positioned across the bioprosthesis using primarily the right anterior oblique orthogonal fluoroscopic view and deployed under rapid ventricular pacing. The goal was to achieve 10% to 20% of the prosthesis on the atrial side of the sewing ring (for SAPIEN 3, the radiopaque central marker was aligned with the prosthesis sewing ring prior to deployment). The degree of valve expansion was controlled by visual fluoroscopic assessment, aiming to achieve mild flaring of the ends of the valve stent on the ventricular and atrial sides (Figure 5). In the second half of our experience, we observed minimal motion of the mitral annular plane with the transcatheter delivery system in place, and thus selectively omitted rapid ventricular pacing. The SAPIEN position remained stable without the use of rapid pacing in the majority of cases. TEE was used to assess valve position, hemodynamic function, and atrial septostomy, and rule out procedural complications (Figure 6).
Antegrade transseptal approach using a transapical rail
Three cases were performed with the use of a transapical rail (9). An exchange length 0.035-inch angled extra-support glide wire was introduced through the Agilis sheath into the left atrium and advanced across the mitral bioprosthesis/ring/calcified valve into the LV. The Glidewire was snared in the LV and exteriorized through the LV apical sheath, creating a wire rail between the right femoral vein and the LV apex. The valve was positioned and deployed in a similar fashion as described above with the use of rapid ventricular pacing. The LV apical puncture site was subsequently closed with a 6-mm Amplatzer Vascular Plug II (AVP II, St. Jude Medical, St. Paul, Minnesota) that expanded to fill the LV apical defect. Anticoagulation was reversed with protamine, and the venous access site was subsequently closed by securing the Perclose device sutures.
Atrial septostomy management
In most cases, the iatrogenic atrial septal defect was small with a mild degree of bidirectional shunting seen by color-Doppler. In 1 case, the defect was larger due to the need for dilation with a 20 mm balloon in order to advance the 29 mm SAPIEN XT valve across the septum, and this was successfully closed using a 12 mm Amplatzer Septal Occluder device (St. Jude Medical, St. Paul, Minnesota) with no evidence of residual shunting. In another patient with pulmonary hypertension, after deployment of a 23 mm SAPIEN XT valve and dilation with a 15 mm Tyshak balloon, there was a large amount of right-to-left shunting, prompting closure of the septostomy with a 12 mm Amplatzer Septal Occluder device. In a third case due to presence of previous stroke and concomitant pacemaker leads the atrial septum was closed using a 25 mm Gore Cardioform Septal Occluder device (Gore Medical, Flagstaff, Arizona). The introduction of the SAPIEN 3 Commander delivery system has facilitated smoother crossing of the atrial septum, allowing for use of smaller pre-dilation balloons and smaller residual defects.
Complications including conversion to open surgery, myocardial infarction, stroke, emergency surgery, bleeding, and vascular complications were reported according to the VARC-2 (Valve Academic Research Consortium Procedural) criteria (10). Device success was defined as the absence of procedural mortality, the correct positioning of a single transcatheter valve, and the absence of residual moderate or severe prosthetic regurgitation or stenosis. Prosthetic function was assessed before discharge by transthoracic echocardiography. Transcatheter prosthesis and periprosthetic regurgitation was graded as absent, trace, mild, moderate, or severe.
In-hospital and post-discharge adverse events were prospectively recorded. All patients were prescribed oral anticoagulation (warfarin) with goal international normalized ratio of 2.0 to 3.0 and single antiplatelet therapy (aspirin 81 mg daily or clopidogrel 75 mg daily if indicated for other purposes). Thirty-day and 1-year follow-up medical evaluations were performed at the treating institution or through the patients’ local physician. Thirty-day and 1-year transthoracic echocardiogram data were collected. No patients were lost to follow-up.
Society of Thoracic Surgeons risk score was calculated using the mitral valve replacement algorithm. Continuous variables were expressed as mean ± SD if normally distributed or median with interquartile range if skewed. Paired t tests and Wilcoxon signed rank tests compared pre- and post-procedure variables within patients. We defined surveillance period as the time between the procedure and the last clinical contact with the patient. Analyses were performed using JMP statistical software, version 9 (SAS Institute, Cary, North Carolina).
Mitral valve implantation
A total of 48 patients underwent percutaneous transvenous mitral SAPIEN valve implantation during the study period. Mean age was 76 ± 11 years, and 29 (60%) were female. The mean Society of Thoracic Surgeons risk score was 13.2 ± 7.4%. Median follow-up was 40 days (range: 1 to 491 days). Additional patient characteristics are shown in Table 1. Procedural characteristics are shown in Table 2. Median number of post-procedure hospital days was 2 days with 16 (33%) requiring time in the intensive care unit. Fifteen (31%) patients were dismissed from the hospital the day after the procedure and 10 (21%) patients were discharged 2 days after the procedure.
Mitral valve implantation in failed bioprosthetic valves
A total of 33 patients underwent percutaneous transseptal implantation of SAPIEN valve within a dysfunctional mitral bioprosthetic valve (mode of failure regurgitation in 20, stenosis in 11, combined in 2) (Table 3). Of these procedures, 31 (94%) were successful, whereas 2 (6%) died during valve deployment of LV apical perforation due to wire/catheter nosecone injury. No patient experienced stroke or myocardial infarction after the procedure. One patient developed a hemothorax early after the procedure related to transapical access for the rail delivery, which was successfully managed with a tube thoracostomy. One patient died 7 days after the procedure during vancomycin infusion, with autopsy showing no acute cardiac abnormalities, suggesting that cause of death was a drug reaction (Figure 7). Only 11 patients required intensive care unit stay following the procedure, including the 1 patient with hemothorax and 3 patients that required prolonged ventilation due to respiratory failure. Twenty patients were transferred directly to the medical floor from the catheterization laboratory and did not require intensive care. There were no access site bleeding complications. Eighteen (55%) patients were discharged from the hospital within 1 to 2 days of having the procedure. Twenty-nine (88%) patients were discharged to home as opposed to a skilled nursing facility. Of note, no LV injury complications have occurred since the removal of apical access and Lunderquist wire from the procedure. Additionally we observed that the SAPIEN 3 Commander delivery system more easily crossed the atrial septum compared to the larger profile XT and SAPIEN systems.
Mitral valve implantation in failed annuloplasty rings
Nine patients with failed mitral annuloplasty rings (5 for regurgitation, 3 for stenosis, 1 combined regurgitation and stenosis) underwent percutaneous SAPIEN valve implantation (Table 4). Of these procedures, 2 were complicated by valve migration into the left atrium within minutes after deployment. Both patients remained hemodynamically stable and underwent surgery using conventional open sternotomy to remove the SAPIEN valve, and replace the mitral valve. Of the 2 embolized valve in ring procedures, 1 was an incomplete 34-mm Carbomedics band (Sorin, Arvada, Colorado) and the other was a complete 29-mm St. Jude Medical Tailor band. The mechanism of embolization in the first was likely due to the incomplete ring allowing more annular expansion, and in the second case was likely due to device malposition with inadequate portion of valve deployed on the ventricular aspect of the ring. The remaining 7 procedures were successful (78%). All patients were alive at 30-day follow-up. One of the 7 successful procedures was complicated by an incidentally noted LV apical pseudoaneurysm discovered on transthoracic echocardiogram the next day, likely caused by the LV Lunderquist anchor wire. The pseudoaneurysm was successfully treated with percutaneous closure using a 14 mm Amplatzer vascular plug II device 1 day after the valve-in-valve procedure (Figure 8). Of the 7 successful procedures, the mean gradient was reduced to <7 mm Hg in all patients and all patients had no more than mild prosthetic or periprosthetic regurgitation. One patient had LV outflow tract obstruction due to anterior leaflet displacement immediately after valve deployment but remained hemodynamically stable. Due to persistent symptoms and a peak gradient of 61 mm Hg, the patient underwent a successful elective surgery to resect the anterior leaflet via an aortotomy, leaving the transcatheter mitral valve in place with post-operative LV outflow tract gradient of 16 mm Hg. Another patient developed symptomatic dynamic LV outflow tract obstruction due to anterior leaflet displacement that was noticed at 30 day follow up (peak gradient 40 mm Hg) that was then managed successfully with hydration. At 30-day follow-up, 1 patient continued to have New York Heart Association (NYHA) functional class III dyspnea, 3 had NYHA functional class II dyspnea, and the remaining 2 had no residual symptoms. The patient that required transaortic anterior leaflet resection developed a sternal wound infection that required debridement and wound vac but had no cardiac symptoms at 30 days.
Mitral valve implantation in severe mitral annular calcification
Six patients with severe MAC underwent percutaneous SAPIEN valve implantation (Table 5). The first procedure in an 80-year-old woman was complicated by apical perforation from the delivery system nosecone after valve deployment with development of cardiac tamponade that could not be successfully repaired surgically. Despite chest compressions during cardiopulmonary resuscitation the deployed SAPIENT XT valve remained in situ. Another procedure was performed on an 85-year-old woman with severe MAC and was complicated by severe regurgitation of the initially deployed valve, requiring a second valve that embolized in the left atrium, subsequently requiring urgent open surgical repair. The other 4 (67%) of these procedures were successful and uncomplicated, with all patients experiencing a reduction in the mean gradients, patients having either mild or no residual prosthetic or periprosthetic regurgitation and improvement in symptoms. No patient developed significant outflow tract obstruction. One of these 6 procedures was performed using planned venoarterial ECMO, which was successfully weaned at the end of the procedure, with the remaining 5 performed without ECMO. At 30-day follow-up all patients were alive, with 4 of 5 experiencing improvement in symptoms. The 1 patient requiring emergency surgery developed persistent heart failure requiring readmission and continues to have NYHA functional class IV symptoms. One patient subsequently died 48 days after the procedure due to complications related to a fall and cervical vertebral fracture. The remaining 3 patients were alive and experiencing no residual symptoms at 357, 63, and 31 days of follow-up, respectively.
Learning curve for transseptal mitral valve in valve
To analyze the effect of the learning curve and modifications made to improve and simplify the procedure technique based on experience, outcomes were compared in the group of patients undergoing mitral valve in valve (degenerated bioprosthesis patients only, excluding ring and MAC) before (group A) and after (group B) key changes were made (specifically, elimination of transapical access, replacement of the Lunderquist wire with Safari wire, and utilization of Dexterity sheath in place of Agilis sheath). Higher rates of procedural success and lower rates of complications including LV perforation and major bleeding were noted in group B versus group A (Table 6). There was also a significant reduction in the total procedure duration between these 2 groups (114 ± 28 min vs. 86 ± 30 min; p = 0.05).
Thirty-day survival free of death and cardiovascular surgery was 85% in the overall group and 91% in the failed bioprosthetic mitral valve subgroup. One patient (29-mm SAPIEN XT in 31-mm Hancock II; Medtronic, Minneapolis, Minnesota) developed prosthetic valve thrombosis that manifested as increased prosthesis gradients while on therapeutic anticoagulation with warfarin and was diagnosed using TEE demonstrating leaflet thickening and reduced leaflet motion. The valve thrombosis was successfully treated with increasing the target international normalized ratio range to 3.0 to 3.5 (Table 7). As mentioned previously, 1 patient that underwent mitral valve-in-ring procedure had dynamic LV outflow tract obstruction that was successfully managed with increased hydration, and another required an elective surgical resection of the anterior mitral valve leaflet. Of the patients who reached 30-day follow-up (n = 37), 34 (92%) experienced a significant improvement in functional status and reported NYHA functional class I to II symptoms. At follow-up the right ventricular systolic pressure had decreased compared to immediately post-procedure (47 ± 13 mm Hg vs. 60 ± 17 mm Hg; p = 0.03). Echocardiographic analysis of these patients at 30 days showed no significant changes compared to post-procedure echocardiogram (mean gradient 7.0 ± 2.7 mm Hg; mitral valve area 1.8 ± 0.8; the majority had non- or trivial regurgitation, 8 had mild prosthetic regurgitation, 1 had mild perivalvular regurgitation, and 0 had ≥ moderate prosthetic or periprosthetic regurgitation). Thus far, 5 patients have reached 1-year follow-up and of these, functional status and prosthesis function have remained unchanged.
In this report we identified the following: 1) antegrade transvenous transseptal mitral valve implantation with the SAPIEN transcatheter valve is technically feasible and has a high success rate in the setting of a failed mitral bioprosthesis; 2) steps to simplify the procedure and experiential learning were important in improving procedural outcomes; and 3) transseptal valve-in-valve implantation for failed rings or annular calcification is more challenging and requires further study. These findings should serve to advance the development of the transvenous transseptal approach for transcatheter mitral valve implantation.
To date this is the largest series of percutaneous transvenous transseptal implantation of SAPIEN valves into the mitral position. The antegrade transvenous transseptal implantation of the SAPIEN valve into the mitral position is not only feasible but offers a truly minimally invasive, effective treatment for patients with bioprosthetic mitral valve failure. During the experience described in this report we have developed techniques to minimize complication rates, thus increasing the safety of the procedure. It is notable that since the introduction of the Safari wire with its double curve and atraumatic design, we have observed no cases of LV injury. The high success rate in patients with bioprostheses was demonstrated in a wide variety of prosthesis types, sizes and in mode of failure, demonstrating the versatility of the SAPIEN valve system. The ability to add additional volume to deployment balloon helps ensure optimal deployment such that the ends of the valve stent are splayed and securely anchored visually during valve deployment. Another notable aspect of the data presented here is the high prevalence of patients (52%) that were discharged from the hospital 1 to 2 days after percutaneous mitral valve implantation, which highlights the minimally invasive nature of this procedure and the potential for substantially improved patient satisfaction, recovery time and hospitalization costs. At 30-day follow-up the majority of patients were NYHA functional class I to II, prosthesis function remained stable and there was further reduction in pulmonary hypertension compared to immediately post-procedure. Warfarin was prescribed for all patients prior to hospital discharge due to concern over the potential risk of late valve thrombosis. The optimal adjunctive antiplatelet and antithrombotic therapy is unknown for patients undergoing mitral valve-in-valve implantation, and longer-term follow-up will be needed to address this question.
Our results also show promise for this technique in patients with complete mitral rings, although the success rate was lower and complication rate higher in these patients. In patients with pre-existing annuloplasty rings, we noted favorable application of this technique in patients with semi-rigid or flexible rings (ability to deform ring to a circular shape and minimize paravalvular leak) and in those with complete rings (less risk of device embolization). Despite this, LV outflow tract obstruction due to either anterior leaflet displacement into the LV outflow tract or ventricular aspect of valve stent obstructing LV outflow remains a concern and was observed in 2 patients in our series. Factors including the aortomitral angle, LV geometry, anterior mitral leaflet length and mobility, and transcatheter valve depth and flaring within the ventricle may all contribute to the phenomenon of LV outflow tract obstruction. Preliminary data from the VIVID (Valve in Valve International Data) registry has similarly shown higher rates of LV outflow tract obstruction, all-cause mortality and additionally higher rates of residual mitral regurgitation in patients undergoing mitral valve-in-ring procedures (11).
Finally, the results of our series of patients with MAC suggest that percutaneous SAPIEN valve implantation holds promise for this challenging group of patients to treat. In our series 4 of 6 of procedures were successful, with 1 procedure complicated by valve embolization and another resulting in patient mortality due to LV perforation. The potential for annular rupture or LV perforation underscores the need for a more detailed analysis of the CT characteristics of MAC that may help predict which patients may be best treated with this approach. Data from the worldwide SAPIEN in MAC registry are also highly anticipated, as are the results from the MITRAL (Mitral Implantation of TRAnscatheter vaLves) trial.
Alternative transcatheter mitral valve delivery approaches including transapical and transatrial approaches have also been successfully used and show promise. Advantages of these approaches include more direct delivery (transapical), direct visualization (transatrial) and ability to immediately manage complications surgically. However, these approaches are not percutaneous and may have longer hospital stays and have the potential for more surgical-related complications (e.g., respiratory failure, major bleeding). Some advantages of the transseptal technique described in this manuscript include its total percutaneous technique, rapid patient mobilization and short hospital length of stay. Data from the VIVID registry, which includes a large proportion of transapical access (79%), is highly anticipated to shed further light on the relative merits of different delivery approaches (11).
Although this is the largest series to date of transvenous transseptal mitral valve implantation and includes patients from selected tertiary referral centers, the overall sample size is still relatively small and is an inherent limitation. Future series of a larger number of patients treated using similar techniques and with even longer follow-up duration will be required to better understand the role of this exciting and novel therapy. Furthermore, this data should serve to advance the development of dedicated devices for transseptal mitral valve implantation.
Percutaneous antegrade transvenous mitral valve implantation in failed surgical prostheses is a minimally invasive, feasible, and highly effective treatment for either prosthetic stenosis or regurgitation. Early and midterm outcomes are excellent in patients undergoing successful transvenous mitral valve in valve, and further study of long-term outcome data is required. Percutaneous mitral valve implantation in patients with failed annuloplasty rings and mitral stenosis due to MAC shows promise but has significant challenges that require further study.
WHAT IS KNOWN? Surgical mitral valve replacement in patients with previous surgery or severe mitral annular calcification is often associated with high or prohibitive risk.
WHAT IS NEW? Transfemoral percutaneous transvenous transseptal mitral valve implantation in high-risk patients with degenerated bioprosthesis can be performed safely and is associated with rapid improvement in hemodynamics, shorter length of stays, and improved functional status.
WHAT IS NEXT? Larger-scale studies and data on long-term outcomes of patients undergoing percutaneous mitral valve-in-valve implantation are needed, as well as the development of dedicated devices for transseptal mitral valve implantation.
For a supplemental figure, please see the online version of this article.
Dr. Williams has served as a consultant for Edwards Lifesciences; and has received research funding from Medtronic. Dr. Whisenant has served as a consultant for Edwards Lifesciences and Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- computed tomography
- extracorporeal membrane oxygenation
- left ventricular/ventricle
- mitral annular calcification
- New York Heart Association
- transesophageal echocardiography
- Received December 9, 2015.
- Revision received January 29, 2016.
- Accepted February 25, 2016.
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