Transcatheter edge-to-edge mitral repair

INTRODUCTION — Transcatheter edge-to-edge mitral repair (TEER) is a minimally invasive percutaneous technique for treatment of selected patients with symptomatic mitral regurgitation (MR). TEER reduces MR by improving the coaptation of the anterior and posterior mitral leaflets.

This topic reviews TEER, with a focus on preprocedure evaluation, periprocedural management, complications, and postprocedure care.

General management and indications for interventional (transcatheter or surgical) management of chronic primary and secondary MR are presented separately. (See "Chronic primary mitral regurgitation: General management" and "Chronic secondary mitral regurgitation: General management and prognosis" and "Chronic primary mitral regurgitation: Choice of intervention" and "Surgical procedures for severe chronic mitral regurgitation" and "Chronic secondary mitral regurgitation: Intervention".)

TYPES OF MR — MR is caused by primary or secondary mitral valve disease (table 1). Since the clinical course and treatment of primary and secondary MR differ, identification of the type (primary or secondary) and cause of MR is required for appropriate management. Some individuals require management of both primary and secondary MR [1,2]. (See "Clinical manifestations and diagnosis of chronic mitral regurgitation".)

●Primary MR – Primary MR is caused by a primary abnormality of one or more components of the valve apparatus (leaflets, chordae tendineae, papillary muscles, annulus). Degenerative mitral valve disease with mitral valve prolapse is the most common cause of chronic primary MR in resource-abundant countries. Rheumatic heart disease is a prominent cause of primary MR in resource-limited countries (particularly during the first two decades of life), but it is an uncommon cause of MR in resource-abundant countries. (See "Mitral valve prolapse: Clinical manifestations and diagnosis" and "Clinical manifestations and diagnosis of rheumatic heart disease", section on 'Mitral regurgitation'.)

●Secondary MR – Secondary MR (also known as functional MR) is MR caused by left ventricular (LV) disease (dilation, abnormal shape, and/or dysfunction) and/or dilation of the left atrium and mitral annulus [1-3]. Secondary MR-associated LV dysfunction may be due to coronary artery disease or (nonischemic) cardiomyopathy. Secondary MR associated with left atrial dilation is commonly associated with atrial fibrillation and/or heart failure with preserved ejection fraction [2,4].

CLINICAL SETTING — The management of primary or secondary MR includes general management with intervention (TEER or mitral valve surgery) in selected patients. A multidisciplinary heart team approach (including primary [general] cardiologists, interventional cardiologists, cardiac surgeons, imaging specialists, valve and heart failure specialists, and cardiac anesthesiologists) is recommended for the evaluation and care of potential candidates for mitral valve intervention, including selection of the choice of intervention [5].

Management, including indications for TEER, is discussed separately:

●For chronic secondary MR – (See "Chronic secondary mitral regurgitation: General management and prognosis" and "Chronic secondary mitral regurgitation: Intervention" and "Surgical procedures for severe chronic mitral regurgitation".)

●For chronic primary MR – (See "Chronic primary mitral regurgitation: General management" and "Chronic primary mitral regurgitation: Indications for intervention" and "Chronic primary mitral regurgitation: Choice of intervention".)

●For acute MR – Limited off-label use of TEER for acute MR has been reported, as discussed separately. (See "Acute mitral regurgitation in adults", section on 'Transcatheter edge-to-edge repair'.)

AVAILABLE TECHNOLOGY — While a number of technologies are in clinical development (see 'Investigational technologies' below), two mitral repair systems (MitraClip and PASCAL) are the only US Food and Drug Administration (FDA)-approved devices for TEER. The FDA approved the MitraClip system for primary MR for patients with prohibitive surgical risk in 2013 and for secondary MR in 2019. The FDA approved the PASCAL system for primary MR for patients with prohibitive surgical risk in 2022. The MitraClip and PASCAL systems also have CE Mark approval.

TEER technology is based on the surgical Alfieri edge-to-edge repair, which involves suturing together the middle segments of the anterior and posterior mitral valve leaflets, thereby creating a "double orifice" mitral regurgitant area [6]. The transcatheter mitral devices may be attached similarly at middle segments or in noncentral (including commissural) locations.

●The MitraClip system utilizes a cobalt chromium clip covered with a polypropylene fabric that grasps both the anterior and posterior mitral valve leaflets either simultaneously or sequentially, thereby reducing MR by increasing the coaptation between the regurgitant valve leaflets. In some cases, a second clip may be required to adequately reduce the MR severity toward a goal of final regurgitant severity ≤2+ [7].

●The PASCAL system includes a spacer, two paddles, and two clasps constructed from nitinol and covered in polyethylene terephthalate. The nitinol design is pliable, allowing conformation to the mitral valve anatomy, and the device can also be elongated in the ventricle to navigate more easily through dense chordal structures. The PASCAL system attaches (simultaneously or serially) to the mid-anterior and posterior mitral valve leaflets to each side of the spacer [8]. The PASCAL system is available in two sizes, the original PASCAL implant (with 10 mm wide paddles) and the PASCAL Ace implant (with more curved 6 mm wide paddles).

CONTRAINDICATIONS — Contraindications to MitraClip or PASCAL implantation include:

●Active endocarditis of the mitral valve

●Thrombus of the femoral vein, inferior vena cava, or intracardiac thrombus (eg, left atrial thrombus)

●Intolerance of procedural anticoagulation or postprocedural antiplatelet agents

●Untreatable hypersensitivity or contraindication to contrast media

●Rheumatic mitral valve disease or mitral stenosis

PASCAL implantation is also contraindicated in patients with untreatable hypersensitivity or contraindication to nitinol alloys (nickel and titanium).

PREPROCEDURAL EVALUATION

Cardiac imaging — When intervention is contemplated, knowledge of the detailed mitral valve anatomy is needed to effectively communicate the necessary information to the interventional team. The anatomical description of the mitral valve proposed by Carpentier (figure 1) divides the posterior leaflet into anterolateral (P1), middle (P2), and postero-medial (P3) scallops. While the anterior leaflet does not have obvious anatomical divisions, corresponding segments are labeled similarly A1 to A3.

Echocardiography (with adjunctive real-time three-dimensional [3D] imaging) is critical to aid in identifying appropriate candidates for TEER and for preprocedural planning. Expert examination of the mitral valve on two-dimensional (2D) transthoracic echocardiography (TTE) generally enables determination of the location and extent of disease for procedural planning [9,10].

2D and 3D transesophageal echocardiography (TEE) are commonly also required, as TEE provides superior delineation of the anatomy [11]. It is important that the TEE be performed at the valve center where the procedure will be performed to ensure adequacy of the examination. TEE enables determination of the location of the major leaflet pathology, the size and extent of a flail segment, and whether there is adequate leaflet support for clip implantation. 3D TEE enhances the visualization of the valve with improved localization of the leaflet pathology and demonstration of anatomic features unsuitable for treatment with the clip, such as a cleft leaflet, vegetations, and perforations [12-15].

With increased use of 3D TEE, cleft-like indentations of the posterior mitral leaflet are more frequently recognized, and may be present in up to one-third of patients with myxomatous mitral valve prolapse (movie 1) [16]. Appropriate recognition of cleft-like indentation is important when planning surgical intervention or TEER. However, it must be emphasized that not all cleft-like indentations apparent on 3D reconstruction are associated with mitral regurgitation (ie, many are "nonfunctional" clefts, being visible only during diastole, which do not require repair). The best approach to determine the significance of cleft-like indentation is to examine the mitral valve anatomy from the LV en-face view, with 3D TEE with and without color Doppler.

3D TEE also allows insights into the dynamic mitral annulus function, with early systolic area contraction and saddle-shape deepening contributing to mitral competency. The mitral annulus in mitral valve prolapse is also dynamic but considerably different from normal patients, with loss of early systolic area contraction and diminished saddle-shape deepening despite similar magnitude of ventricular contraction, suggestive of ventricular-annular decoupling [17].

Accurate measurement of the mitral valve parameters (annulus area and perimeter, inter-commissural and septal-lateral diameters) is required for TEER. These can be reliably measured by either 3D TEE or computed tomography (CT). Cardiac CT is not routinely required for TEER procedural planning but may be useful in certain instances, including for quantitation of mitral annular calcification and for evaluation of patients with suboptimal anatomy for TEER who are being considered for investigational transcatheter mitral valve replacement therapy. (See 'Investigational technologies' below.)

Quantitation of MR — The determination of MR severity and etiology should be based on careful, quantitative echocardiographic assessment. Cardiovascular magnetic resonance imaging may be helpful for quantitation of MR if echocardiographic assessment is technically limited or uncertain. (See "Clinical manifestations and diagnosis of chronic mitral regurgitation" and "Echocardiographic evaluation of the mitral valve" and "Transesophageal echocardiography in the evaluation of mitral valve disease".)

We use the following criteria for moderate-severe (3+) or severe (4+) MR, as specified in the EVEREST II trial [18]. At least three of the following criteria should be met:

●Color flow jet may be central and large (>6 cm² or >30 percent of left atrial area) or smaller if eccentric, encircling the left atrium

●Pulmonary vein flow may show systolic blunting or systolic flow reversal

●Vena contracta width ≥0.5 cm measured in the parasternal long-axis view

●Regurgitant volume of ≥45 mL/beat

●Regurgitant fraction ≥40 percent

●Regurgitant orifice area ≥0.30 cm²

Anatomic requirements for TEER — Several anatomic features of the mitral valve must be examined to assess the feasibility of TEER with either the MitraClip or PASCAL systems [19]. The anatomy in patients with MR ranges from ideal anatomy for TEER to very complex anatomy that is unsuitable or very challenging for TEER. Operator experience is important when considering TEER in patients with more challenging anatomy.

The standard anatomic criteria for TEER include:

●Measurements including:

•Planimetered mitral valve area (in parasternal short-axis view at tips of the mitral valve) ≥4.0 cm².

•Minimum leaflet length of 6 mm for MitraClip NT, 8 mm for PASCAL (ACE and standard) devices, and 9 mm for MitraClip XT devices.

•If mitral leaflet flail is present, width of the flail segment <15 mm and flail gap of <10 mm. Flail gap is defined as the greatest distance between the ventricular side of the flail segment and the atrial side of the opposing leaflet (measured in the four-chamber long-axis and LV outflow tract views).

●Minimal mitral leaflet calcification in the grasping area.

●Absence of pathologic mitral leaflet cleft associated with a regurgitant jet. Nonregurgitant clefts or leaflet indentations separating individual scallops can still be compatible with TEER.

●Absence of severely restricted leaflet motion.

●Absence of vegetations and perforations.

Risk assessment — A multidisciplinary heart team described above (see 'Clinical setting' above) assess the prognosis and risk of intervention in potential candidates for TEER. This includes assessing the risk associated with TEER and other treatment options (such as mitral valve surgery in patients with primary MR). (See "Chronic primary mitral regurgitation: Choice of intervention" and "Estimating the risk of valvular procedures".)

Methods for assessing the procedural risk in patients undergoing mitral TEER are under development. The MitraScore was developed as an aid in predicting mortality in patients with primary MR or secondary MR treated with TEER [20]. This score assigns 1 point to each of the following independent predictors: age ≥75 years, anemia, glomerular filtration rate <60 mL/min/1.73 m², LV ejection fraction <40 percent, peripheral artery disease, chronic obstructive pulmonary disease, high diuretic dose, and lack of for renin-angiotensin system inhibitor. For each point, the relative risk of mortality increased by 55 percent (hazard ratio 1.55, 95% CI 1.44-1.67).

PROCEDURE — Transcatheter mitral valve repair with the MitraClip or PASCAL device is performed in the cardiac catheterization laboratory using a combination of fluoroscopic and TEE guidance.

●General anesthesia – Because of the need for TEE guidance and careful device manipulation, the procedure is usually performed under general anesthesia. General anesthesia alters cardiac loading conditions and may modify the degree of MR, heart rate, cardiac output, and valve gradients. Antithrombotic therapy is discussed below. (See 'Antithrombotic therapy' below.)

●TEE probe placement – The feasibility and safety of performing TEE should have been demonstrated by a preprocedure TEE performed to assess candidacy for TEER. If difficulties occurred with the preprocedure TEE, then assessment of the esophagus should be completed before the TEER procedure.

●Access – Access is obtained via the femoral vein, and a transseptal puncture is performed to cross the interatrial septum into the left atrium.

●Device implantation – The steerable catheter is then advanced into the left atrium, and echocardiographic guidance is utilized to align the MitraClip or PASCAL device with the regurgitant valve leaflets and into the LV. The MitraClip or PASCAL is then drawn back with the clip arms open in order to grasp the leaflets at the site of regurgitation. The arms are then closed, and Doppler echocardiography is used to determine the consequent reduction in MR.

●Additional measures to reduce MR – If the reduction in MR is not adequate after placement of the initial device, the device arms can be reopened and the placement adjusted prior to final device deployment. In approximately 40 percent of cases, an additional device may be implanted in order to adequately reduce MR [7].

If an additional device is likely to be needed, then the first device should be placed so that any residual MR is located to one side as a single jet (rather than splitting the residual MR jet). Determining whether an additional device is feasible without resulting in severe mitral stenosis is a key decision. Prior to placement of an additional device, a Doppler-based assessment of the transmitral diastolic pressure gradient is mandatory. Planimetry of the mitral valve orifice may also be useful for intraprocedure decision-making. If an elevated gradient or reduced mitral orifice is present after the initial device, then a second device is not feasible, and it may be necessary to leave some residual MR.

●TEE – During the procedure, real-time 2D and 3D TEE guides the positioning of the transseptal puncture, placement of the TEER device, and assessment of the mitral valve morphology and regurgitation severity following the device placement [12,21]. Intraprocedural TEE enables detecting finer anatomic details (eg, ruptured chords, more precise location of origin of mitral regurgitant jet) than with TTE. (See "Anesthesia for percutaneous cardiac valve interventions".)

ANTITHROMBOTIC THERAPY — Antithrombotic therapy in patients undergoing TEER includes management of anticoagulation prior to the procedure, anticoagulation during the procedure, and anticoagulation or antiplatelet therapy after the procedure. Individualization of antithrombotic therapy is sometimes required due to variations in bleeding and thrombotic risks.

Management prior to transcatheter mitral valve repair — For patients receiving anticoagulation prior to TEER, anticoagulants should be discontinued prior to the procedure to allow sufficient time for restoration of normal coagulation. This is done primarily to enable safe vascular access for a large-bore catheter and transseptal access that can be complicated by inadvertent puncture into the pericardium or aorta. For example, vitamin K antagonist (warfarin) should generally be discontinued at least three days prior to the procedure and an international normalized ratio ≤1.7 verified prior to the procedure. Similarly, direct oral anticoagulants (such as dabigatran) should be discontinued prior to the procedure.

During the time that long-term anticoagulation is subtherapeutic prior to TEER, heparin may be used if deemed appropriate based on an individualized assessment of the risk of thrombosis and bleeding. If subcutaneous low molecular heparin is used, it should be discontinued 12 hours prior to the procedure (ie, the last dose administered 24 hours prior to the procedure). If intravenous unfractionated heparin is used, it should be discontinued at least four hours prior to the procedure.

During the procedure — During the procedure, heparin is administered to maintain an activated clotting time >250 seconds; a therapeutic level is especially important after uncomplicated transseptal puncture.

Postprocedural management — Following the procedure, patients are treated with anticoagulation or antiplatelet therapy; patients should receive anticoagulant or antiplatelet therapy for at least six months following the procedure:

●For patients with an indication for anticoagulation (eg, atrial fibrillation), vitamin K antagonist or direct oral anticoagulant is reinitiated.

●For patients who do not have an indication for anticoagulation, antiplatelet therapy consisting of aspirin and/or clopidogrel is used [18,22,23]. If aspirin is used, a loading dose of 325 mg aspirin can be followed by 81 mg daily. If clopidogrel is used, a loading dose of 300 mg of clopidogrel is recommended (within 24 hours prior to the procedure or immediately following the procedure) followed by 75 mg daily. At least one of these antiplatelet agents should be continued for six months or longer.

These recommendations are based on extrapolation from limited data on device endothelialization [24].

COMPLICATIONS OF TRANSCATHETER MITRAL VALVE REPAIR — Early (30-day) complication rates are primarily due to need for periprocedural blood transfusion, while late events are primarily related to underlying heart failure or patient comorbidities [25].

Complications after TEER should be considered in the context that the vast majority of patients undergoing TEER have been deemed have high to prohibitive surgical risk, typically due to advanced age, frailty, and the presence of comorbid conditions. Patients with secondary MR undergoing TEER will continue to have variable degrees of LV dysfunction, which may be associated with increased risk of heart failure and mortality.

Fewer data are available from patients treated with PASCAL compared with MitraClip due to the more recent approval of PASCAL by the FDA.

Mortality — A study of transcatheter mitral procedures submitted between 2014 and March 31, 2020 to the Society of Thoracic Surgeons/American College of Cardiology (STS/ACC) Transcatheter Valve Therapy Registry included 33,878 TEER procedures (for primary and secondary MR) [26]. During this time period, the mortality rate for TEER declined from 5.6 to 4.1 percent at 30 days and from 27.4 to 22.0 percent at one year.

A meta-analysis compared adverse events in 785 patients who underwent TEER using PASCAL and 796 who underwent TEER with the MitraClip in five observational studies and one randomized trial [27]. Composite periprocedural and in-hospital mortality rates were similar (0.64 and 1.66 percent in the PASCAL and MitraClip groups, respectively).

Stroke — In the above cited meta-analysis, rates of periprocedural cerebrovascular accidents were similar in the two device groups: 0.26 percent in the PASCAL group and 1.01 percent in the MitraClip group [27].

Bleeding — Due to the large sheath size, and despite access being venous rather than arterial, TEER poses a risk of access site bleeding. However, the rate of significant bleeding is generally lower for TEER than for mitral valve surgery:

●In the EVEREST II trial, 13 percent of patients randomized to TEER (n=184) required transfusion of ≥2 units of blood, compared with 45 percent of patients who underwent surgical mitral valve repair [18].

●In the EVEREST II high-risk study, 17.9 percent of patients required transfusion of ≥2 units of blood [28].

●In registries of TEER, the percentage of patients who required ≥2 units of blood transfusion has been significantly lower, ranging from 0.9 to 3.9 percent [29,30].

Inadequate device attachment — Device embolization is an exceedingly rare complication of MitraClip placement. More commonly, the clip may detach from one of the leaflets, resulting in single leaflet device attachment, which is usually associated with recurrent severe MR; this complication can usually be treated with surgery and, rarely, by repeat TEER. Low rates of single leaflet device attachment have been reported in studies and generally occur during the procedure or in the first 30 days postprocedure.

In the EVEREST II study, nine patients out of 184 were noted in the first 12 months to have single leaflet device attachment; one additional patient developed single leaflet device attachment from years 1 to 4. All of these patients were treated with subsequent mitral valve surgery [18].

In the STS/ACC Transcatheter Valve Therapy Registry postapproval study, single leaflet device attachment occurred in 1.5 percent of patients and device embolization occurred in 0.1 percent of patients undergoing TEER with MitraClip [31]. In the CLASP 2D trial the 30-day rate of single leaflet device attachment was 0.9 percent with PASCAL and 0 percent with MitraClip [32].

Mitral stenosis — TEER may create an increase in diastolic pressure gradient across the mitral valve, and the development of clinically significant mitral stenosis is a potential complication. As with other forms of mitral stenosis, the transmitral gradient is dependent on not only the resultant size of the mitral valve orifice after TEER but also on heart rate and the magnitude of transmitral flow (ie, forward cardiac output).

●Hemodynamic studies of mitral valve area before and after MitraClip implantation have not shown clinically significant increases in mean diastolic mitral valve gradients or reduction in mitral valve area acutely or at 12-month follow-up [33]. There were also no differences in mitral valve hemodynamics between patients who had one versus two clips placed [34].

●Individual cases of mitral stenosis after MitraClip implantation have been reported in one patient with borderline preprocedure mitral valve area and in another patient on dialysis who developed late calcific changes resulting in mitral stenosis [35,36].

●Exercise testing may be useful for the assessment of the hemodynamic and clinical impact of possible mitral stenosis after TEER. As with native valve mitral stenosis, exercise-related increases in heart rate and cardiac output may result in significant increases in mitral valve gradient and pulmonary artery pressures.

Infective endocarditis — Limited information is available on the risk of infective endocarditis following MitraClip or PASCAL implantation, since published data are limited to sporadic case reports [37,38]. Patients who have undergone TEER should be instructed regarding the importance of careful dental hygiene and prompt medical care for fever or other signs of infection.

For patients with prosthetic material used for valve repair, antibiotic prophylaxis is indicated for relevant dental or oral procedures that involve manipulation of gingival tissue or the periapical region of the teeth or perforation of the oral mucosa. This recommendation is consistent with 2020 ACC/American Heart Association and 2021 European Society of Cardiology valve guidelines [1,39]. (See "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)

Oropharyngeal/esophageal injury — Endotracheal intubation or TEE for mitral TEER procedures is associated with a risk of oropharyngeal and esophageal injury. In one series including 272 TEER procedures, the risk of such injuries was 1.5 percent [40].

Oropharyngeal injury may occur during endotracheal intubation for general anesthesia or placement of the TEE probe. Such injuries are typically lacerations or tears of the mucosa that resolve with conservative measures; however, these may require prolonged intubation and general anesthesia requiring intensive care unit care after the TEER procedure.

Esophageal tears or, rarely, perforation may also occur with TEE probe placement and manipulation, and the risk of this may be higher for more prolonged procedures requiring more extensive probe manipulation.

INVESTIGATIONAL TECHNOLOGIES — A number of transcatheter investigational devices for mitral valve repair are in various stages of development. These devices work by a number of mechanisms [41,42]:

●Altering the geometry of the mitral valve annulus via direct or indirect annuloplasty to reduce the severity of MR. The CARILLON Mitral Contour system implants a nitinol device in the coronary sinus that indirectly cinches the mitral annulus [43,44]. The CARILLON device has CE Mark approval for use in Europe.

●Chordal replacement.

●Remodeling the ventricle, thereby reducing the severity of secondary MR.

●Transcatheter mitral valve replacement (with a bioprosthetic valve) is an investigational alternative to TEER [45,46].

Each of these technologies requires rigorous evaluation of risk/benefit and long-term durability in the treatment of MR.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Cardiac valve disease".)

SUMMARY AND RECOMMENDATIONS

●Clinical use – Transcatheter edge-to-edge mitral repair (TEER) is a minimally invasive percutaneous technique for treatment of selected patients with symptomatic mitral regurgitation (MR). TEER reduces MR by improving the coaptation of the anterior and posterior mitral leaflets. (See 'Clinical setting' above.)

Indications for TEER are discussed separately:

•For chronic secondary MR – (See "Chronic secondary mitral regurgitation: General management and prognosis" and "Chronic secondary mitral regurgitation: Intervention" and "Surgical procedures for severe chronic mitral regurgitation".)

•For chronic primary MR – (See "Chronic primary mitral regurgitation: General management" and "Chronic primary mitral regurgitation: Indications for intervention" and "Chronic primary mitral regurgitation: Choice of intervention".)

•For acute MR – Limited off-label use of TEER for acute MR has been reported as discussed separately. (See "Acute mitral regurgitation in adults", section on 'Transcatheter edge-to-edge repair'.)

●Available technology – TEER technology (with the MitraClip or PASCAL system) reduces MR by increasing the coaptation between the anterior and posterior mitral valve leaflets. (See 'Available technology' above.)

●Contraindications – Contraindications to MitraClip or PASCAL implantation include active endocarditis, rheumatic mitral valve disease or mitral stenosis, intracardiac thrombus (eg, left atrial thrombus), intolerance of procedural anticoagulation, or postprocedural antiplatelet agents and contraindication to contrast media. PASCAL implantation is also contraindicated in patients with untreatable hypersensitivity or contraindication to nitinol alloys (nickel and titanium). (See 'Contraindications' above.)

●Role of imaging – Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE; with adjunctive real-time three-dimensional [3D] imaging) are critical to preprocedural planning. Fluoroscopy and TEE (two-dimensional [2D] and 3D) are used to guide the implantation procedure. (See 'Cardiac imaging' above and 'Procedure' above.)

The determination of MR severity and etiology should be based on careful, quantitative echocardiographic assessment. Cardiovascular magnetic resonance imaging may be helpful for quantitation of MR if echocardiographic assessment is technically limited or uncertain. (See "Clinical manifestations and diagnosis of chronic mitral regurgitation" and "Echocardiographic evaluation of the mitral valve" and "Transesophageal echocardiography in the evaluation of mitral valve disease".)

●Complications – Complications of TEER include mortality, stroke, bleeding (particularly at the access site), and inadequate device attachment. Although the diastolic pressure gradient across the mitral valve increases following device insertion, development of clinically significant mitral stenosis is rare. (See 'Complications of transcatheter mitral valve repair' above.)

●Prevention of endocarditis – Patients who have undergone TEER should maintain good dental hygiene, receive prompt medical care for fever or other signs of infection, and receive antibiotic prophylaxis for relevant dental or oral procedures. (See 'Infective endocarditis' above and "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Sorin Pislaru, MD, PhD, who contributed to earlier versions of this topic review.