Version May 2024
INTRODUCTION — Management of patients with chronic primary mitral regurgitation (MR) is based upon an understanding of the pathophysiology and natural history of the disease (table 1) and the efficacy and timing of mitral valve repair and replacement.
Primary MR is caused by a primary abnormality in one or more components of the valve apparatus (leaflets, chordae tendineae, papillary muscles, annulus). Mitral valve prolapse (MVP) is the most common cause of chronic primary MR in resource-abundant countries [1]. 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'.)
The only effective treatment for severe MR is valve repair or valve replacement. Indications for intervention for chronic primary MR are discussed separately (see "Chronic primary mitral regurgitation: Indications for intervention"). The choice of intervention for chronic severe primary MR is reviewed here.
Other aspects of management of chronic primary MR are discussed separately:
●(See "Chronic primary mitral regurgitation: General management".)
●(See "Transcatheter edge-to-edge mitral repair".)
●(See "Mitral valve prolapse: Overview of complications and their management".)
APPROACH TO INTERVENTION FOR CHRONIC PRIMARY MR
●Heart team – A multidisciplinary dedicated heart team approach (including primary [general] cardiologists, interventional cardiologists, cardiac surgeons, imaging specialists, valve and heart failure specialists, and cardiac anesthesiologists) is recommended for evaluation and care of patients with chronic severe primary MR who may be candidates for intervention [2-4].
Indications for intervention and choice of intervention are evaluated by the heart team based upon the patient's clinical presentation (symptoms), the cause of MR, specific mitral valve anatomy, estimated surgical (operative) risk, life expectancy, frailty, comorbidities, values, and preferences [2,3]. Indications for transcatheter or surgical intervention for patients with primary MR are discussed separately (algorithm 1). (See "Chronic primary mitral regurgitation: Indications for intervention".)
●Assessment of surgical risk – Surgical risk is generally assessed by a risk model for valve surgery such as the Society of Thoracic Surgeons (STS) model, which estimates risk of in-hospital mortality and complications of valve surgery (with or without coronary artery bypass graft surgery) based upon patient characteristics and conditions, as discussed separately. (See "Estimating the risk of valvular procedures".)
Prohibitive risk for mitral valve surgery is determined by the multidisciplinary heart team based upon identifying one or more of the following surgical risk factors:
•Thirty-day STS predicted operative mortality risk score of ≥8 percent for patients likely to undergo mitral valve replacement or ≥6 percent for patients likely to undergo mitral valve repair.
•Porcelain aorta (extensively calcified ascending aorta).
•Frailty (assessed by in-person cardiac surgeon consultation).
•Hostile chest (conditions that make a sternotomy or thoracotomy for valve surgery prohibitively hazardous).
•Severe liver disease/cirrhosis (Model for End-Stage Liver Disease [MELD] score >12).
•Severe pulmonary hypertension (systolic pulmonary artery pressure greater than two-thirds systemic pressure).
•Extenuating comorbidities (eg, right ventricular dysfunction with severe tricuspid regurgitation, major bleeding diathesis, internal mammary artery graft at high risk of injury).
●Choice of intervention – In patients with severe chronic primary MR, a choice is made between the following procedures: surgical valve repair, surgical valve replacement, and transcatheter edge-to-edge mitral repair (TEER) (algorithm 1).
•For surgical candidates – For patients with primary MR with an indication for mitral valve intervention who do not have prohibitive surgical risk, surgical intervention consists of valve repair when a successful and durable repair is expected. The decision on whether to attempt mitral valve repair (rather proceeding directly with valve replacement) is based upon the mitral valve anatomy and the surgeon's experience. For isolated severe primary MR limited to less than one-half of the posterior leaflet, mitral valve repair is the procedure of choice. (See 'Surgical valve repair versus replacement' below.)
A surgical mitral valve repair procedure involves repair of the valve, assessment of the success of the repair with intraoperative transesophageal echocardiography (TEE; under the same loading conditions as in the awake state), and, if the repair is deemed inadequate, the repair is generally revised. If the valve cannot be adequately repaired, the procedure is converted to mitral valve replacement.
Intraoperative TEE is recommended since it can enhance the success of valve repair and can reliably predict early and late mitral valve dysfunction [2,3,5]. (See "Transesophageal echocardiography in the evaluation of mitral valve disease", section on 'Role of intraoperative transesophageal echocardiography'.)
•For prohibitive surgical risk – For patients with symptomatic severe primary MR with prohibitive surgical risk and suitable mitral valve anatomy, we suggest TEER rather medical management of heart failure. Preprocedure evaluation for TEER and other aspects of the procedure are discussed separately. (See "Transcatheter edge-to-edge mitral repair" and 'Transcatheter edge-to-edge repair' below.)
MITRAL VALVE SURGERY
Surgical valve repair versus replacement — As noted above, for patients with chronic primary MR with an indication for mitral valve intervention with acceptable operative risk, when mitral valve repair is feasible, it is generally preferred to mitral valve replacement, based upon the following considerations [2,3]:
●Observational studies suggest that mitral valve repair is associated with a lower operative mortality rate than mitral valve replacement. (See 'Survival' below and 'Risk of reoperation' below.)
●Mitral valve repair avoids complications of prosthetic heart valves, including risks of thromboembolism and need for anticoagulation (particularly with mechanical valves) and risk of structural valve failure (particularly with bioprosthetic valves). (See "Mechanical prosthetic valve thrombosis or obstruction: Clinical manifestations and diagnosis".)
Survival — A number of retrospective studies have identified higher survival rates in patients with chronic primary MR undergoing valve repair compared with valve replacement [6-15]. The following illustrative findings were reported from a Medicare database study of 47,279 patients aged 65 years or older who underwent primary isolated mitral valve surgery between 2000 and 2009 with a median follow-up of five years [13]:
●Operative mortality was 3.9 percent for patients who had mitral valve repair compared with 8.9 percent in those who had mitral valve replacement.
●One-, five-, and 10-year Kaplan-Meier survival estimates were greater among those who underwent mitral valve repair (91, 77, and 54 percent versus 83, 65, and 37 percent, respectively, for mitral valve replacement).
●The one-, five-, and 10-year survival benefits with mitral valve repair were also seen in those aged 75 years or greater (88, 71, and 40 percent survival with repair versus 80, 60, and 28 percent survival with replacement). (See "Valvular heart disease in older adults", section on 'Mitral valve repair'.)
A meta-analysis of eight observational studies with a total of 4599 patients (mean age 62 to 69 years; 3064 mitral valve repairs and 1535 mitral valve replacements performed during 1973 to 2014) followed for a mean of three to nine years found that mitral valve replacement was associated with an increased risk of mortality (hazard ratio 1.68, 95% CI 1.35-2.09) [15]. The benefit of mitral repair was greater during later surgical eras.
Risk of reoperation — In patients with primary MR, surgical mitral valve repair and surgical mitral valve replacement are generally associated with similar rates of subsequent mitral valve reoperation [15], as illustrated by the following studies:
●In the Emory experience of patients undergoing surgery between 1984 and 1997, the rate of reoperation for mitral valve replacement at five years was 6 percent for patients who had undergone mitral valve repair and 4 percent for those who had undergone mitral valve replacement [11]. However, at the end of 10 years, the rate of reoperation was lower in the mitral repair patients (22 percent) compared with mitral replacement patients (34 percent).
●Lower rates of reoperation were noted in a cohort of patients undergoing mitral valve surgery during a slightly later time period. In the Mayo experience for initial repairs in the 1990s, the linearized risk of reoperation after repair of the posterior leaflet (0.5 percent per year) compared favorably with the risk of reoperation after mechanical valve replacement (0.7 percent per year) and all mitral valve replacements (0.7 percent per year) [16]. The risk of reoperation following bilateral and anterior leaflet repair were nominally higher (0.92 and 1.64 percent per year), although not statistically different. The durability of repair for anterior leaflet prolapse improved during the second decade of the study.
Lower rates of reoperation following mitral valve repair in later series likely reflect technical advances (eg, use of more effective anterior leaflet prolapse repair techniques such as polytetrafluoroethylene [PTFE] chordal replacement), greater experience, and earlier patient referral [16,17]. (See 'Mitral valve repair' below.)
Catheter-based procedures (transcatheter edge-to-edge repair and valve-in-valve transcatheter mitral valve implantation) now enable treatment of many patients with late postintervention valve dysfunction, so not all patients with significant recurrent MR require surgical reintervention.
Mitral valve repair — Techniques for mitral valve repair include annuloplasty ring implantation, leaflet resection/remodeling, neochordae implantation, and edge-to-edge (Alfieri) repair.
The likelihood of successful and durable mitral valve repair depends upon mitral valve anatomy, the cause of MR, and surgical technique and expertise.
●Anterior versus posterior leaflet repair – With routine use of multiple techniques, the repairability of anterior leaflet and bileaflet pathologies is similar to that for isolated (P2) posterior leaflet prolapse [16,18]. This was illustrated by a study of propensity matched pairs consisting of 309 patients who underwent anterior leaflet repair (85 isolated, 224 bileaflet) and 309 patients who underwent posterior leaflet repair [19]. The study identified similar rates of residual MR in the two groups (8 percent with no residual MR) and similar survival rates at 10 years (72 and 74 percent) and 15 years (63 and 60 percent). The incidence of reoperation at 15 years was 7.5 percent after anterior repair and 4.9 percent after posterior repair.
Similarly, a meta-analysis of 10 studies found similar rates of long-term survival, freedom from moderate to severe MR, and freedom from reoperation in patients who underwent anterior/bileaflet repair compared with those who underwent posterior leaflet repair [20].
●Rheumatic mitral disease – Successful mitral valve repair has generally been considered less likely in patients with rheumatic mitral disease than in patients with degenerative disease [2], although some have reported comparable results using specialized techniques with stringent quality control [21,22].
Mitral valve replacement — When mitral valve replacement is required, a choice is made between a mechanical or bioprosthetic valve. Mechanical valves have the disadvantage of requiring lifelong warfarin therapy, while bioprosthetic valves have the disadvantage of limited durability due to valve degeneration, particularly in patients under age 65. When valve replacement is necessary, choice of a bioprosthetic or mechanical valve is made by considering factors including valve durability, need for lifelong anticoagulation with mechanical valves, and impact on overall mortality (table 2). (See "Choice of prosthetic heart valve for surgical aortic or mitral valve replacement" and "Mechanical prosthetic valve thrombosis or obstruction: Clinical manifestations and diagnosis".)
Concurrent procedures — Patients with chronic primary MR undergoing mitral valve surgery frequently have concurrent conditions such as coronary artery disease, tricuspid regurgitation, and atrial fibrillation (AF), which may be managed with interventions at the time of mitral valve surgery.
●Coronary artery disease – Obstructive coronary lesions are commonly revascularized at the time of mitral valve surgery, as concurrent bypass surgery typically adds little morbidity or mortality to the procedure [2].
●Tricuspid regurgitation – The role of concurrent tricuspid repair in patients undergoing mitral valve surgery for chromic primary MR is discussed separately. (See "Management and prognosis of tricuspid regurgitation", section on 'Indications'.)
●Atrial fibrillation – Patients with chronic MR who are undergoing valve repair or replacement often have concomitant AF. The role of performing an intraoperative procedure to manage AF at the time of mitral valve surgery is discussed separately. (See "Atrial fibrillation: Surgical ablation", section on 'Indications'.)
The role of surgical left atrial appendage occlusion in patients with AF undergoing cardiac surgery is discussed separately. (See "Atrial fibrillation: Left atrial appendage occlusion".)
TRANSCATHETER EDGE-TO-EDGE REPAIR — The outcomes of transcatheter edge-to-edge mitral valve repair (TEER) for primary MR have been investigated in a number of cohort studies as well as a randomized trial comparing transcatheter repair with surgical repair (the EVEREST II trial) (see 'Comparison with surgical mitral valve repair' below) and a randomized trial comparing the PASCAL and MitraClip systems. (See 'Comparison of devices' below.)
TEER outcomes — Studies of TEER for primary MR have shown procedural success rates (including postimplantation MR less than moderate) generally over 90 percent and in-hospital mortality rates of 0 to 4 percent [23-26]. A key concern is the risk of recurrent MR requiring reintervention. (See 'Comparison with surgical mitral valve repair' below.)
MitraClip system — Most of the available data are for the MitraClip system. A Society of Thoracic Surgeons/American College of Cardiology (STS/ACC) Transcatheter Valve Therapies Registry study included 19,088 consecutive patients (median age 82 years; median STS-predicted mortality risk with surgical mitral repair 4.6 percent) with moderate to severe or severe primary MR with mitral valve prolapse or flail who underwent nonemergency TEER with the MitraClip device in the US from 2014 through 2022 [25].
●At 30 days, the mortality rate was 2.7 percent, stroke 1.2 percent, and mitral valve reintervention 0.97 percent. The percentage of patients with New York Heart Association functional class III/IV declined from 76.8 percent at baseline to 15.8 percent at 30 days.
●MR success (defined as moderate or less residual MR after repair and mean mitral gradient <10 mmHg) was observed in 95.2 percent of patients at the end of the procedure and in 89.0 percent of patients at 30 days. MR success based on echocardiographic data from all time points was 88.9 percent. The percentage of patients with MR success increased from 81.5 percent in 2014 to 92.2 percent in 2022.
●At one year, the incidence of death was 15.4 percent, heart failure admission 9.3 percent, and mitral valve reintervention 3.4 percent. Patients with mild or less residual MR and mitral gradients of 5 mmHg or less had lower mortality (11.4 versus 26.7 percent; adjusted hazard ratio [HR] 0.40, 95% CI 0.34-0.47) and heart failure readmission rates (6.2 versus 16.9 percent; adjusted HR 0.35, 95% CI 0.30-0.41) compared with patients with unsuccessful procedures.
PASCAL system — Early outcomes with the PASCAL system are described below in the CLASP IID trial comparing the PASCAL and MitraClip systems. (See 'Comparison of devices' below.)
A report from the CLASP IID Registry included 98 patients with greater than moderate primary MR, prohibitive surgical risk, and complex mitral valve anatomy who were deemed suitable for treatment with the PASCAL system [27]. The one-year Kaplan-Meyer estimate of all-cause mortality was 10.7 percent, of composite major adverse events was 16.5 percent, and of heart failure hospitalization was 8.5 percent.
Reduction in mitral regurgitation — Successful TEER leads to a reduction in MR severity to moderate or less as assessed by echocardiography. Several studies have reported the efficacy of transcatheter repair in reducing MR severity:
●For the MitraClip system
•In the EVEREST II trial, the prevalence of greater than moderate MR at four years was 21 percent [28,29], although 24.8 percent required surgery for mitral valve dysfunction.
•In the high-risk and continued access registry of the EVEREST II trial, 16.4 percent of patients had greater than moderate MR at one year [30]. Thus, successful TEER was associated with sustained reduction in MR severity in the majority of patients at one-year follow-up.
●For the PASCAL system – In the above-cited report from the CLASP IID Registry for the PASCAL system, at one year, 6.8 percent had greater than moderate MR and 42.4 percent had greater than mild MR [27].
Left ventricular reverse remodeling — MR causes a chronic volume overload that leads to dilation of the left atrium and left ventricle (LV). Correction of MR is associated with LV remodeling with a reduction in LV chamber size. Even though transcatheter repair often does not completely eliminate MR, reduction in MR to moderate or less is associated with some degree of LV reverse remodeling:
●In a study of 801 patients undergoing MitraClip implantation, reduction in MR at 12 months was associated with a reduction in both LV end-diastolic volume and left atrial volume [31].
●In the EVEREST II trial, surgical repair was associated with a greater reduction in LV volumes, likely due to less residual MR [28].
Comparison with surgical mitral valve repair — Both TEER and surgical repair of the mitral valve reduce or eliminate MR in properly selected patients. The EVEREST II randomized trial compared the outcomes of TEER with surgical mitral repair or replacement among 279 patients with greater than moderate MR who were candidates for either procedure [28]. Most of the patients had heart failure at baseline (91 percent in the TEER group and 78 percent in the surgical group). A primary regurgitant jet originating from malcoaptation of the middle scallops of the anterior and posterior leaflets was required. Most of the patients (73 percent) had primary MR. Among the patients undergoing mitral valve surgery, 86 percent underwent repair and 14 percent underwent mitral valve replacement. The following results were obtained at 12 months follow-up:
●TEER and mitral valve surgery were associated with similar rates of overall mortality at one year (6 percent for both).
●Postprocedural greater than moderate MR occurred at a similar rate in the two groups (21 versus 20 percent).
●Major adverse event rates at 30 days were significantly lower in the TEER group compared with the surgical group (15 versus 48 percent). This was largely due to the higher rate of transfusion of at least 2 units of blood in the surgical group (13 versus 45 percent).
●At four-year follow-up, the overall rates of mortality (17.4 versus 17.8 percent) and of greater than moderate MR (21.9 versus 24.7 percent) remained similar in the TEER and surgical groups [29]. However, surgery for mitral valve dysfunction was significantly higher in the TEER group (24.8 versus 5.5 percent).
●The primary composite endpoint for efficacy was freedom from death, from surgery for mitral valve dysfunction, and from greater than moderate mitral regurgitation at 12 months. This endpoint was more frequent in the surgery group (73 versus 55 percent) due to the higher rate of subsequent surgery for mitral valve dysfunction in the TEER group (20 versus 2 percent).
Comparison of devices — The MitraClip and PASCAL systems are the two US Food and Drug Administration-approved and CE Mark-approved TEER devices.
The CLASP IID randomized trial in patients with symptomatic greater than moderate primary MR and prohibitive surgical risk compared the safety and efficacy of the PASCAL system with the MitraClip system [26].
●At six months, the percentage of patients with moderate or less MR was similar for the PASCAL and MitraClip systems (96.5 versus 96.8 percent).
In the PASCAL group, the percentage of patients with mild or less MR at discharge (87.2 percent) was preserved at six months (83.7 percent). In the MitraClip group, the percentage of patients with mild or less MR at discharge (88.5 percent) declined to 71.2 percent at six months.
●The composite major adverse event rates (cardiovascular mortality, stroke, myocardial infarction, new need for renal replacement therapy, severe bleeding, and nonelective mitral valve reintervention) at 30 days were also similar (3.4 percent for the PASCAL system and 4.8 percent for the MitraClip system).
●Functional capacity and quality-of-life outcomes at six months were improved similarly in the two groups.
The MitraClip and PASCAL systems and the TEER procedure are discussed further separately. (See "Transcatheter edge-to-edge mitral repair".)
INVESTIGATIONAL APPROACHES — Transcatheter mitral valve replacement via a transfemoral transseptal approach is under investigation as an option for patients with native severe MR with prohibitive surgical risk who do not have anatomy favorable for TEER [32].
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
●Heart team approach – 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 evaluation and care of patients with chronic severe primary mitral regurgitation (MR) who may be candidates for intervention. Indications for intervention are discussed separately. (See "Chronic primary mitral regurgitation: Indications for intervention".)
●Prohibitive risk – Prohibitive risk for mitral valve surgery is identified by the multidisciplinary heart team based on the presence of one or more of the following surgical risk factors:
•Thirty-day Society of Thoracic Surgeons (STS)-predicted operative mortality risk score of ≥8 percent for patients likely to undergo mitral valve replacement or ≥6 percent for patients likely to undergo mitral valve repair.
•Porcelain aorta (extensively calcified ascending aorta).
•Frailty (assessed by in-person cardiac surgeon consultation).
•Hostile chest (conditions that make a sternotomy or thoracotomy for valve surgery prohibitively hazardous).
•Severe liver disease/cirrhosis (Model for End-Stage Liver Disease [MELD] score >12).
•Severe pulmonary hypertension (systolic pulmonary artery pressure greater than two-thirds systemic pressure).
•Extenuating comorbidities (eg, right ventricular dysfunction with severe tricuspid regurgitation, major bleeding diathesis, internal mammary artery graft at high risk of injury).
●Choice of intervention – In patients with severe chronic primary MR, a choice is made between the following procedures: surgical valve repair, surgical valve replacement, and transcatheter edge-to-edge mitral repair (TEER) (algorithm 1).
•For surgical candidates – For patients with primary MR with an indication for mitral valve intervention, surgical intervention consists of valve repair when a successful and durable repair is expected. The decision on whether to attempt mitral valve repair is based upon the mitral valve anatomy and the surgeon's experience. (See 'Surgical valve repair versus replacement' above.)
Observational studies have found that mitral valve repair is associated with higher survival rates than mitral valve replacement. Rates of reoperation on the mitral valve are similar following mitral valve repair and mitral valve replacement. (See 'Survival' above and 'Risk of reoperation' above.)
•For prohibitive surgical risk – For patients with symptomatic severe primary MR with prohibitive surgical risk and suitable mitral valve anatomy, we suggest TEER rather medical management of heart failure (Grade 2C).
TEER procedural success rates (including less than moderate postimplantation MR) are generally over 90 percent, and in-hospital mortality rates are 0 to 4 percent. TEER devices and procedures are discussed further separately. (See 'Transcatheter edge-to-edge repair' above and "Transcatheter edge-to-edge mitral repair".)
ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges Sorin Pislaru, MD, who contributed to earlier versions of this topic review.
The UpToDate editorial staff also acknowledges William H Gaasch, MD (deceased), who contributed to earlier versions of this topic.
آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
