Author + information
- Received February 23, 2017
- Revision received May 31, 2017
- Accepted June 29, 2017
- Published online October 2, 2017.
- Marina Urena, MD, PhDa,
- Dominique Himbert, MDa,∗ (, )
- Eric Brochet, MDa,
- Jose Luis Carrasco, MDb,
- Bernard Iung, MDa,
- Patrick Nataf, MDc and
- Alec Vahanian, MDa
- aDepartment of Cardiology, Bichat Claude Bernard Hospital-Paris VII University, Paris, France
- bDepartment of Anesthesiology, Bichat Claude Bernard Hospital-Paris VII University, Paris, France
- cCardiovascular Surgery Department, Bichat Claude Bernard Hospital-Paris VII University, Paris, France
- ↵∗Address for correspondence:
Dr. Dominique Himbert, Bichat Claude Bernard Hospital, 46 Henri Huchard, 75018 Paris, France.
Transcatheter mitral valve replacement (TMVR) using balloon-expandable valves has become an alternative therapy for selected patients with mitral valve disease. Up to now, the transapical approach has been the preferred route, but the transseptal approach is becoming increasingly popular due to its reduced invasiveness and increased safety. However, transseptal TMVR procedures are technically challenging, and little is known about the screening process required before this therapy. The authors provide operators with a step-by-step approach from the screening process to follow-up care for transseptal TMVR procedures.
- annuloplasty ring
- mitral annular calcification
- transcatheter mitral valve replacement
Despite the major progress achieved over the past few decades, a significant proportion of patients with severe mitral valve disease and symptoms are not referred for surgery (1,2). The presence of severe comorbidities, advanced age, and unfavorable anatomical conditions are the main reasons advocated for denying to surgery (1,2). Patients with prior mitral bioprosthesis or ring annuloplasty failure and those with severe mitral annulus calcification (MAC) are at particularly high-risk of death and major complications after surgery (3,4).
Transcatheter mitral valve replacement (TMVR) has emerged as an alternative treatment for these patients, although data are limited (5–15). A few commercially available transcatheter heart valves (THVs), mostly the SAPIEN family (Edwards Lifesciences, Irvine, California) (5–7,9–13) and the Lotus device (Boston Scientific, Natick, Massachusetts) (14,15) and mainly 2 approaches, transapical and transseptal (TS), have been used for TMVR on a compassionate use basis. Although due to its technical easiness the transapical approach is the most commonly used (12), it has been associated with an increased risk for periprocedural complications and mortality and a slower recovery (16). Thus, the TS approach might be a better option for this high-risk population.
This study provides heart teams with a step-by-step approach, from the screening process to follow-up care, to perform TS TMVR procedures using balloon-expandable SAPIEN XT or SAPIEN 3 THVs (Central Illustration).
Step 1. Pre-TMVR Work-Up and Patients Selection
Nowadays, candidates for TMVR are patients with severe symptomatic mitral valve disease and a failing bioprosthesis or ring annuloplasty or a MAC for whom the risk-benefit ratio favors intervention over medical treatment and the heart team favors a nonsurgical approach. To confirm the expected benefit of intervention and avoid futile procedures, a comprehensive evaluation is mandatory to rule out the presence of severe concomitant valve heart disease, a myocardial disease, or comorbidities responsible for the symptoms (17). TMVR work-up includes routine preoperative exams such as standard blood investigations, an electrocardiogram, a chest x-ray, a transthoracic echocardiogram, and a coronary angiogram. A transesophageal echocardiogram (TEE) and retrospectively gated enhanced cardiac multidetector computed tomography (MDCT) with data acquisition in all phases of the cardiac cycle are strongly recommended (18).
The main objectives of the screening process are to identify the severity and mechanisms of mitral valve disease and bioprosthesis or ring failure; determine the morphology of the mitral valve and specific characteristics of surgical bioprostheses or rings; determine the risk of complications such as left ventricular outflow tract (LVOT) obstruction, paravalvular leaks, or embolization; and help in the planning of the procedure.
Identification of the mechanisms of bioprosthesis or ring failure or mitral valve disease
The presence of endocarditis, severe paravalvular leaks, and partial dehiscence of the bioprosthesis or ring contraindicate the procedure and should be ruled out by TEE. In patients with stenotic bioprostheses, it is mandatory to differentiate thrombus, which contraindicates the procedure, from pannus and degeneration. In this sense, the clinical history (i.e., timing, quality of anticoagulation) and both TEE and cardiac MDCT are very useful (Figure 1) (19). Likewise, when facing patients with high transmitral gradients and failing rings or bioprostheses, the occurrence of significant prosthesis-patient mismatch should be excluded before performing TMVR. It should be suspected in case of normal mobility and morphology of leaflets despite elevated gradients with no pannus, thrombus, or degeneration on the TEE and MDCT. In addition, the analysis of the evolution of transmitral gradients from the post-operative period is helpful.
Characterization of the mitral valve
Morphology and specific characteristics
Surgical bioprosthesis or ring
Being aware of the specific characteristics of the bioprosthesis or ring as reported by manufacturers, as well as the findings and results of preceding surgical procedures, is critical for an accurate planning. In this sense, the smartphone platform developed by Bapat (20) is very useful.
• True internal diameter and dimensions: In TMVR valve-in-valve procedures, the true internal diameter of bioprostheses is used as a reference in the sizing process of the THV (21). It is less useful for TMVR valve-in-ring interventions. In addition, to know the height of the stent of the bioprosthesis is helpful to define the fluoroscopic landmarks for the THV positioning and implantation.
• Rigidity and completeness of rings: Rigid oval rings will not conform to the round shape of the prosthesis and are associated with a high risk of paravalvular or central leaks and high transmitral gradients. Likewise, open rings may increase the risk of paravalvular leaks and embolization of the prosthesis. Thus, patients with semirigid or flexible complete rings of at least 27 mm are the optimal candidates for valve-in-ring procedures.
• Radiopacity and fluoroscopic appearance: The presence of radiolucent bioprostheses or rings may be associated with an increased risk of malpositioning of the THV. In these cases, THV positioning and implantation will be exclusively guided by TEE.
• Position and orientation: Surgical reports may provide valuable information regarding the position (annular vs. supra-annular) and orientation of the bioprosthesis or ring, which may have an impact on the risk of LVOT obstruction. They should be analyzed on MDCT images.
Mitral annulus calcification
It is crucial to determine the likelihood of anchoring of a THV. An analysis of the extension and thickness of calcifications and the dimensions of the annulus is mandatory. Although a circumferential calcification is not required, the presence of focal calcification with reduced extension contraindicate the procedure. An extensive calcification of the posterior annulus and some degree of calcification in the internal and lateral part of the annulus seem to be essential for the anchoring. However, calcification of the anterior part of the annulus may not be necessary, in particular, for those patients with radiation-associated valve disease or in the presence of an aortic prosthesis. Figure 2 shows MDCT of a noncircumferential calcified mitral annulus in a patient undergoing successful TMVR. Of note, a severe asymmetry of the mitral annulus is not a contraindication for TMVR in MAC, given that even asymmetrical native annulus may become circular when the prosthesis is implanted (Figure 3).
Dimensions of the mitral annulus or bioprosthesis or ring and sizing of the THV
An example of measurement of a mitral annulus, ring, and bioprosthesis is displayed in Figure 4. The sizing of the THV relies mainly on their true internal diameter as reported by the manufacturers for patients with failing bioprosthesis, although other parameters such as the morphology and calcification of leaflets and the presence of pannus, which are identified by TEE or MDCT, have to be considered. Details on the MDCT imaging process have been previously reported (21). For patients with a failing ring or MAC, we strongly recommend the use of MDCT to determine the dimensions (diameters and area) of the mitral annulus. However, the measurement of the dimensions of the mitral annulus may be challenging due to its saddle shape, especially in patients with a MAC. It has been suggested that tracing a D-shaped annulus limited anteriorly by the trigone to trigone distance may accurately estimate the dimension of the annulus (22). Mitral valves with calcified leaflets and noncircumferential calcification of the annulus are particularly challenging, given the difficulty to differentiate the calcified base of the leaflet from the mitral annulus. The extension and severity of calcification on the mitral annulus should determine the degree of THV oversizing, with a greater degree of oversizing for the lesser calcified annulus.
Given the huge differences in the systolic pressures of the left atrium and left ventricle, in patients with native mitral valve disease, greater degrees of valve oversizing than those used for aortic valve interventions are recommended to avoid late migration or embolization of the prosthesis. In our experience, a proper sizing of the THV is reached with a 10% to 25% degree of oversizing depending on the extension and severity of calcifications and an extra-filling of the balloon with 2 to 3 ml of contrast to flower the prosthesis. As a general law, small THVs (≤23 mm) should be avoided except for particular cases (i.e., small elderly patients), due to the risk of high residual gradients.
Morphology of the mitral leaflets and subvalvular apparatus in patients with mitral rings or MAC
Both the anterior leaflet and the anterior subvalvular apparatus contribute to the obstruction of the LVOT and have to be carefully evaluated with both MDCT and TEE. This is particularly important in patients with a failing reconstructive mitral surgery and ring annuloplasty resulting in elongated and thick anterior leaflets (Figure 5).
Assessment of the risk of LVOT obstruction
The factors associated with an increased risk of LVOT obstruction are multiple: a small LVOT and left ventricular cavity, an acute mitral-aorta angle (23), an elongated, thick, or severely calcified anterior leaflet and bulky calcification of the subvalvular apparatus (Figure 6). Thus, it is not surprising that the risk of LVOT obstruction is lower in patients with surgical bioprostheses compared with failing rings or native valves with MACs. This protective effect of bioprostheses is mainly due to the absence of anterior leaflet and subvalvular apparatus and the protection of the stent. Nonetheless, LVOT obstruction may occur in patients with bioprostheses placed deep into the LVOT due to the covering of the stent of the THV with the leaflets of the surgical prosthesis.
According to our experience, the main differential factor regarding the risk of LVOT obstruction is the size of the LVOT and left ventricular cavity, given that the presence of an acute mitral-mitral-aorta angle or elongated or heavily calcified mitral anterior leaflet or subvalvular apparatus are infrequent.
The simulation of the THV on MDCT and the evaluation of the neo-LVOT dimensions are the most accurate techniques to determine the risk of LVOT obstruction (24,25). Figure 7 shows an example of a patient at very high risk (Figures 7A to 7C) and a patient at very low risk, who underwent TMVR without complications (Figures 7D to 7F). When the simulated prosthesis (or an elongated anterior leaflet or calcified mitral subvalvular apparatus) touches the interventricular septum in end-systole reducing the neo-LVOT dimensions <100 mm2, the risk is very high. In addition, it has been proposed to assess the hypothetical LVOT clearance assuming the implantation of a tubular device by measuring the distance between the septal bulge and the margin of the projected annulus area at 15 or 20 mm into the left ventricle (26). Of note, it is strongly recommended to place the simulated prosthesis as ventricular as possible, given the final position of the THV may be more ventricular than initially intended.
In patients at high risk of LVOT obstruction due to a hypertrophic septum, a prophylactic septal alcohol ablation or a hybrid approach with a surgical resection of the anterior leaflet and subvalvular apparatus may result in a reduction in the risk of LVOT obstruction. When the main risk factor is a small LV cavity, the procedure should be probably contraindicated.
The software package 3mensio Mitral Valve (Pie Medical Imaging BV, Maastricht, the Netherlands) provides main parameters in a semiautomatic way and may be very useful for the planning of the procedure (18).
In addition, the TEE is useful to determine the morphology of the interatrial septum to anticipate difficulties with the TS catheterization and the presence of thrombus in the left atrial appendage, which contraindicates the procedure, and the MDCT provides the most accurate C-arm projection as well as fluoroscopic markers for an accurate THV positioning.
Last, a reconstructed 3-dimensional printed model based on CT images may help to confirm in vitro the suitability of TMVR with a specific device, in particular in patients with challenging anatomy (15,25).
In conclusion, the screening for TMVR procedures remains a challenge, in particular in patients with MAC or failing rings. However, a proper evaluation of the MDCT and TTE/TEE images may provide the necessary information. Although anatomical contraindications for TMVR in patients with failing bioprostheses are infrequent, a nonappropriate anatomy may be more frequently found in patients with failing rings and, mostly, in those with a MAC. In our experience, only a small proportion of patients with a MAC, approximately 1 of 7 to 10 patients evaluated, are proper candidates for TMVR, mostly due to the presence of insufficient calcification, a large dimension of the mitral annulus and a high risk of LVOT.
Step 2. Patient Preparation and Room Setting
The material used in TS TMVR is shown in Online Figure 1. The procedure is performed under general anesthesia. Patient preparation and room setting (catheterization laboratory or hybrid room) do not differ from those of TAVR with general anesthesia. Both groins are prepared for vascular accesses. On the left side, a 4- to 6-F arterial femoral sheath is inserted for continuous arterial pressure monitoring and a venous sheath is used for placing the temporary right ventricular pacing lead. Nonetheless, an arterial sheath may be inserted by radial approach and rapid pacing might be done using coco pins and the stiff wire, as for TAVR. The right venous femoral access is kept free for gaining the TS access. Pre-closing with 1 ProGlide (Abbott Vascular Devices, Santa Clara, California) can be used. The permanent presence of a skilled interventional echocardiographer is mandatory throughout the procedure for continuous TEE guidance.
Step 3. TS Catheterization
The general principles of TS have been previously described (27). There are some specificities associated with TMVR procedures:
1. Echocardiographic guidance: as previously mentioned, TEE is mandatory to determine the optimal puncture site. Although there are no established recommendations concerning TS TMVR, they are very similar to that used for the MitraClip technique (i.e., a superior and posterior puncture to allow for a sufficient maneuverability in the left atrium and crossing the mitral valve).
2. Resistant septum: This is frequent in redo intervention or in patients of older age, after chest radiation. If resistance to crossing the septum with the needle occurs, pressure must be continuously applied until crossing. When crossing is still not possible, radiofrequency may be used by a standard electrosurgical cautery generator via the TS needle, brief pulses being applied to the hub of the TS needle by direct contact (28). If the needle can cross but not the catheter it may be useful to introduce an exchange angioplasty 0.018-inch guidewire into the needle (Steelcore, Abbott Vascular) up to the superior pulmonary vein and use it as support for both the needle and the catheter. If this maneuver fails an exchange angioplasty 0.014-inch guidewire may be introduced into the needle, to withdraw both the needle and the catheter and insert an angioplasty balloon (2.0 mm) to dilate the septum before readvancing the TS catheter over this guidewire. Finally, it may be necessary to redo the puncture at another site.
Step 4. Mitral Valve Crossing
Once the TS sheath has entered the left atrium, a 0.032-inch exchange wire is placed in the left atrium or if preferred, in the upper left pulmonary vein. The Inoue wire (Toray Medical Co., Ltd., Tokyo, Japan) offers an optimal safety and may avoid inadvertent pullback toward the right atrium. Then, the flexible steerable Agilis catheter (St. Jude Medical, St. Paul, Minnesota) is advanced into the left atrium and oriented in front of the mitral orifice. TEE guidance is helpful in combination with fluoroscopy in a projection perpendicular to the mitral annulus, bioprosthesis, or ring. Usually, this projection is found in a marked right anterior oblique view with cranial or caudal angulation. Once the catheter has been correctly placed in front of the mitral orifice, an antegrade crossing is easily obtained using a 5-F diagnostic catheter (mainly multipurpose, pigtail, or amplatz catheters [Cordis, Hialeah, Florida]) mounted on a standard 0.0035-inch J wire. When the catheter has entered the left ventricle, to avoid any wall damage, a 0.035-inch J pre-shaped exchange wire is placed at the apex, on which a pigtail catheter is installed. Then, a J pre-shaped stiff wire is cautiously advanced in the pigtail catheter to create a loop at the apex of the left ventricle and the pigtail is pulled back. An appropriate stiffness is provided by guidewires such as the Amplatz Super Stiff guidewire (Cook Medical, Bloomington, Indiana), the Safari wire (Boston Scientific), and the Confida guidewire (Medtronic, Minneapolis, Minnesota). Although we consider it unnecessary, several techniques have been used to increase the support: first, using a combined TS and transapical approach to create a rail to facilitate tracking of the THV (29), and second, crossing the aortic valve to place the wire in the descending aorta.
Once the stiff wire is safely placed and stable at the apex of the left ventricle, the Agilis catheter is withdrawn and the Edwards E-sheath is installed in the inferior vena cava.
Step 5. THV Preparation
The choice between the SAPIEN XT and SAPIEN 3 THV depends on several parameters, which are presented in Online Table 1. Although the SAPIEN 3 is “off-label” for valve-in-valve indications, it provides substantial advantages over the SAPIEN XT: lower profile, enhanced flexibility, coaxiality and trackability, resheathability, increased radial force and anchoring, and reduced risk of paravalvular leak.
The THV preparation obeys the general principles of Edwards valve preparation, with 2 specificities: 1) an overfilling of an additional 2 to 3 cm3 in the inflation syringe is recommended in valve-in-valve and valve-in-ring cases, and to be discussed in MAC cases, to secure anchoring and avoid secondary atrial migration by achieving a flared appearance of the prosthesis in its ventricular part; 2) the question of the orientation of the THV on the balloon catheter may seem obvious, but any lack of attention may lead to catastrophic consequences: the SAPIEN XT/3 THV is mounted for antegrade implantation (similar to the position in transapical aortic valve procedures) on the catheter.
Step 6. Septal Dilation
The atrial septum is dilated using 12- to 16-mm peripheral balloons such as the ATLAS catheter balloon (Bard Peripheral Vascular, Tempe, Arizona), the IMPACT catheter balloon (Braun, Bethlehem, Pennsylvania), the Mustang balloon (Boston Scientific), or similar balloons tracked on the stiff wire (Figure 8A). Several balloon inflations across the septum are required. Correct positioning of the balloon is determined by fluoroscopy and confirmed by TEE. TEE is also necessary to evaluate the result of dilation, based on the volume of the interatrial left-to-right shunt and on the anatomical aspect of the septal defect. This step is crucial, because insufficient septal dilation may lead to entrapment and blockage of the prosthesis or tear of the septum. The balloon diameter necessary to obtain adequate dilation varies according to the characteristics of the septum (thickness or stiffness) and the type and size of the THV. It is recommended to begin with a 12-mm balloon. Usually, 12-mm dilations are sufficient in most procedures using SAPIEN 3 prostheses, and 14 mm in those using SAPIEN XT prostheses. Just before removal of the balloon, it may be useful to advance it to the mitral orifice to check its trackability and anticipate potential difficulties, which could be encountered with the THV. Regarding mitral valve pre-dilatation, the consensus is that it should be avoided for bioprostheses because of the risk of fracture and embolization of calcified degenerated leaflets, potentially leading to stroke or massive mitral regurgitation (MR). In the very rare cases where it is mandatory because the valve cannot be crossed, it must be done with the utmost caution, using a very short inflation with an undersized balloon. In such cases, the use of cerebral protection devices may be of interest.
Step 7. Advancing the Delivery System and Crossing the Septum
After careful checking of its orientation, the prosthesis is advanced through the sheath, aligned, and adjusted in the inferior vena cava, exactly as is done in the descending aorta during TAVR.
Crossing the septum may be a challenging step. It is guided by fluoroscopy in anterior-posterior projection and by TEE. Once the prosthesis has been advanced into the right atrium, some flexion combined with rotation is given to the catheter to orientate it toward the septum. In addition to fluoroscopic landmarks and TEE guidance, the tactile feedback is crucial to achieving a safe crossing. If some resistance occurs, the catheter should not be pushed forcefully, but removed into the right atrium and another attempt should be made using a different orientation of the catheter. These manipulations require experience from the operator. TEE is useful to identify the cause and site of the entrapment. If crossing is still not possible, the valve should be reintegrated into the sheath and removed, which is usually easy with the SAPIEN 3 prostheses. Then, septal dilation should be completed using a larger balloon and another attempt to cross should be made, if necessary with a stiffer wire to provide better support and trackability of the THV. If reintegration of the THV into the sheath is not possible, the only solution is to remove it with the sheath as a whole via a surgical cutdown. During all these manipulations, it is mandatory to pay continuous attention to the wire at the apex of the left ventricle, to avoid any ventricular damage or inadvertent pullback in the left atrium or even loss of the TS access.
Step 8. Positioning and Deployment of the THV
The rest of the procedure is performed in the projection perpendicular to the plane of the mitral bioprosthesis, ring, or annulus. Just after septal crossing, the catheter is fully flexed, oriented toward the mitral orifice, and carefully advanced into the left atrium. Usually, the catheter advances freely in the left atrium, but the crossing of the mitral orifice may be more challenging because the THV may block against the bioprosthetic ring or calcific bulks of the mitral annulus, or in severely stenotic orifices. In most cases, the obliquity of the THV with regard to the mitral orifice is the cause of blockage. As for septal crossing, the solution is never forceful pushing, but gentle manipulations to find the optimal orientation of the catheter, combined with an adequate support of the wire provided by controlled push-pull movements. If these maneuvers are ineffective, it may be useful to delock the catheter and pull it back, while maintaining the THV in place, just as is done before THV deployment. This maneuver usually facilitates the engagement of the THV through the mitral orifice. Then, the THV is finely positioned, with a final objective of 20% or 30% of the THV toward the left atrium and 70% or 80% toward the left ventricle (Figures 8B and 8C, Online Videos 1 and 2). This final positioning is crucial to avoid paravalvular leaks and atrial migration. The baseline landmarks differ according to the THV used (i.e., SAPIEN XT vs. SAPIEN 3). They also largely differ among patients with bioprostheses, rings, and MAC. Although geometrical characteristics and radiopacity vary among the different brands of surgical bioprostheses, it is usually relatively easy to adequately position the THV in a surgical bioprosthesis. However, it is important to keep in mind that, once the balloon inflation begins, the stent of the prosthesis is no longer observable by TEE, as shown in Figures 9A to 9D and Online Videos 3 and 4. Finally, the frame of the bioprosthesis facilitates the coaxiality with the THV. Positioning is more challenging in surgical rings. Indeed, rings are not flat structures, which renders the optimal anchoring zone more difficult to delineate. In addition, the risk of obliquity of the THV is more important than with bioprostheses, due to the absence de frame. Thus, it is mandatory to achieve an optimal coaxiality before deployment of the THV, through interactions between catheter and wire manipulations. Patients with MAC represent the most challenging cases. Although in some cases annular calcification may provide accurate fluoroscopy landmarks (Figures 10A and 10B, Online Video 5) it may be misleading if it extends toward the left ventricle or the subvalvular apparatus. Again, the role of TEE guidance is irreplaceable to define the most appropriate landing zone.
Once the position of the THV is deemed adequate, it can be deployed under rapid ventricular pacing. It is recommended that the first operator holds the catheter in the left hand and the wire in the right, to be able to finely adjust the position of the THV during its deployment, while the balloon is inflated by the second operator. Before starting balloon inflation, it has to be confirmed that the device is free and might be slightly displaced to adjust its position. Balloon inflation must be done very slowly, to allow for these subtle manipulations; this requires a perfect coordination between both operators. Usually, contrast medium is not used during TMVR.
Step 9. Post-Deployment Assessment and Management
After deployment, a complete evaluation by TEE is mandatory to confirm the optimal function of the THV (final position, presence, severity, and mechanisms of central or paravalvular leaks, transmitral gradients, and motion of leaflets) and to detect potential complications (acute migration, right-to-left interatrial shunt, LVOT obstruction, and tamponade). The following issues may be observed:
1. An improper position (too auricular or ventricular) with a high risk of acute migration of the THV. A second THV should be emergently implanted to secure the first one. In case of an acute ventricular migration, the stiff wire should be left in place and the valve might try to be captured, pulled back to the mitral annulus, and secured with a second valve (30). If the capture of the prosthesis is not possible, a second valve implantation should be rapidly considered at least in those patients with a poor hemodynamic tolerance. In patients with atrial embolization of THV, it has been reported the successful anchoring of a THV in the left atrial appendage (11) and in the interatrial septum using an Amplatzer cardiac plug (St. Jude Medical) (31). Nonetheless, the need of an emergent surgery for the removal of the embolized valve and mitral valve replacement should be rapidly considered and discussed by the heart team.
2. Paravalvular leak (Figure 11A). A high (auricular) position of the THV may result in the presence of significant paravalvular leaks and has to be treated with the implantation of a second valve more distally. When the leak extends around the circumference despite a proper position of the prosthesis, post-dilatation may be necessary. In the presence of a significant leak despite an optimal position and expansion of the THV, a percutaneous closure may be considered. Although infrequent, in patients with failing rings or bioprosthesis, new or, more probably, larger paravalvular leaks between the surgical rings and the patient mitral annulus may be detected after TMVR. In these cases, cardiac surgery should probably be considered, depending on the extension of the leak.
3. Central MR. If it persists after removal of the stiff wire, a second valve may be necessary.
4. High transmitral gradients. Their mechanism has to be identified. When it is due to the incomplete expansion of the prosthesis, post-dilatation is required.
5. Abnormal motion of leaflets (stuck leaflet). The wire should be removed first and if persistent, a second valve implantation should be considered.
6. Bidirectional or mainly right-to-left interatrial shunt resulting in desaturation (Figure 11B). A percutaneous closure should be performed before extubation.
7. LVOT obstruction (Figure 11C). If the cause is the presence of a septal bulge, a rescue alcohol septal ablation may be effective (32). When it is due to the displacement of the mitral anterior leaflet or subvalvular apparatus, the implantation of a self-expanding transcatheter aortic valve in a more ventricular position than usual may be used (33).
8. Tamponade. According to its cause (TS puncture, right or left ventricular perforation), drainage or surgery may be required.
9. If severe hypotension occurs, the presence of severe MR, tamponade, LVOT obstruction, or major vascular complications should be suspected and treated emergently.
In the absence of complication, the patient is extubated at the end of the procedure. The risk of conduction disturbances is very low and the temporary pacing wire is removed. A neurological examination is performed and the patient is transferred to a post-anesthesia care unit or intensive care unit. Ambulation can be initiated within the first 24 h. Compared with the transapical approach, TS procedures allow for a more rapid recovery, with lower pain and earlier ambulation of patients in addition to avoiding the complications associated with the transapical puncture (16).
Currently, there is no evidence-based recommendation for the optimal antithrombotic treatment in this population. It is admitted that the risk of valve thrombosis is higher than in the aortic position. Empirically, a combination of oral anticoagulation using vitamin K antagonists and antiplatelet therapy is recommended for at least 3 months. Then, in patients with no other indication for long-term oral anticoagulation, vitamin K antagonists may be stopped if the bleeding risk is deemed high and 1 antiplatelet agent is continued indefinitely.
Step 10. Follow-Up Care
Little is known about the mid- or long-term outcomes of patients after TMVR. Thus, a careful follow-up is required to detect delayed complications such as late valve displacement or migration, thrombosis, and dysfunction or structural deterioration. In the absence of any in-hospital adverse event, a pre-discharge evaluation with transthoracic echocardiography or TEE or MDCT may be recommended to rule out early subclinical complications such as valve displacement or partial thrombosis, evaluate the volume of any residual interatrial shunting, and serve as a reference for all subsequent evaluations. In addition, the same evaluation might be repeated at 3 to 6 months to confirm the absence of valve thrombosis before making the decision of whether to discontinue the anticoagulation therapy. Also, we recommend repeating these systematic evaluations yearly thereafter and an outpatient clinical assessment including transthoracic echocardiography every 6 months, in close cooperation between implanting centers and referring cardiologists. In case of detection of new or an increase in the severity of paravalvular leaks, a late slight migration of the THV should be suspected. In fact, a few millimeters of backward displacement of the THV may result in the development of new paravalvular leaks by precluding the protective effect of the internal or external skirt of the SAPIEN XT or SAPIEN 3 THVs. Although not exclusively, this complication may more frequently occur in patients with MAC (34,35), and should be ruled out in patients presenting with heart failure and proper immediate results of TMVR. In addition to TEE, a fluoroscopic evaluation of the THV can be very useful. If an increase in transmitral gradients is observed, the presence of early or late valve thrombosis has to be excluded (36). Lifelong anticoagulation therapy should probably be indicated, if no contraindication. Last, the occurrence of endocarditis and the presence of hemolysis should be assessed, in particular in those patients with anemia and paravalvular leaks. Nonetheless, no clinical evidence exists regarding the most appropriate follow-up management after TMVR and it should be interpreted keeping in mind that most of these recommendations are experience-based and should be evaluated in future studies.
Although TS TMVR is technically demanding. an accurate screening process as stated previously, an optimal planning, a strict step-by-step procedural approach and a close follow-up of the patients will result in a high success rate and a reduced risk of complications.
Dr. Himbert has served as a consultant and proctor for Edwards Lifesciences. Dr. Iung has received speaker fees from Edwards Lifesciences. Dr. Vahanian has served as a consultant for Edwards Lifesciences and Abbott; and has received research grant support from Valtech. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- left ventricular outflow tract
- mitral annulus calcification
- multidetector computed tomography
- mitral regurgitation
- transesophageal echocardiogram
- transcatheter heart valve
- transcatheter mitral valve replacement
- Received February 23, 2017.
- Revision received May 31, 2017.
- Accepted June 29, 2017.
- 2017 American College of Cardiology Foundation
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- Himbert D.,
- et al.
- Capretti G.,
- Urena M.,
- Himbert D.,
- et al.
- Central Illustration
- Step 1. Pre-TMVR Work-Up and Patients Selection
- Step 2. Patient Preparation and Room Setting
- Step 3. TS Catheterization
- Step 4. Mitral Valve Crossing
- Step 5. THV Preparation
- Step 6. Septal Dilation
- Step 7. Advancing the Delivery System and Crossing the Septum
- Step 8. Positioning and Deployment of the THV
- Step 9. Post-Deployment Assessment and Management
- Step 10. Follow-Up Care