Chronic secondary mitral regurgitation: Intervention

INTRODUCTION — Secondary mitral regurgitation (MR; also known as functional MR) is MR caused by left ventricular (LV) dysfunction and/or dilation of the left atrium (LA) and mitral annulus, generally with structurally normal or minimally thickened mitral valve leaflets and chordae [1-3].

Secondary MR-associated LV dysfunction may be due to coronary artery disease (CAD) or (nonischemic) cardiomyopathy. In patients with CAD and secondary MR, LV dysfunction may be global or regional (eg, inferolateral myocardial infarction [MI] with posterior leaflet tethering). Secondary MR caused by CAD (generally with MI) is also known as ischemic MR. Secondary MR associated with LA dilation is commonly associated with atrial fibrillation or heart failure (HF) [3,4].

Since the clinical course and treatment of secondary MR differs from that for primary MR (which is caused by a primary abnormality of the mitral valve apparatus), 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 [1,3]. (See "Clinical manifestations and diagnosis of chronic mitral regurgitation".)

The management of chronic secondary MR includes treatment of HF with reduced ejection fraction when present, atrial fibrillation, and LV dyssynchrony, as discussed separately. (See "Chronic secondary mitral regurgitation: General management and prognosis".)

This section focuses on both transcatheter and surgical interventions for chronic secondary MR.

Related issues are discussed separately:

●(See "Clinical manifestations and diagnosis of chronic mitral regurgitation".)

●(See "Pathophysiology and natural history of chronic mitral regurgitation".)

INDICATIONS FOR MITRAL VALVE INTERVENTION

General approach — Indications and choice of intervention for chronic secondary MR are based upon the clinical presentation and whether there is a concurrent indication for other cardiac surgery. A multidisciplinary heart team approach (including primary [general] cardiologists, interventional cardiologists, cardiac surgeons, imaging specialists, valve and HF specialists, and cardiac anesthesiologists) is recommended for the evaluation and care of potential candidates for mitral valve intervention [1,2,5]. Similar recommendations are included in the 2020 American College of Cardiology/American Heart Association valvular heart disease guideline [1] and the 2021 European Society of Cardiology valvular heart disease guidelines [2]. (See "Society guideline links: Cardiac valve disease".)

●Symptomatic patients with secondary MR

•Ventricular secondary MR - For symptomatic patients with HF with LV ejection fraction (LVEF) <50 percent and secondary MR, the mainstay of management is optimized management of HF (pharmacologic therapy plus cardiac resynchronization therapy [CRT], as indicated). Evidence-based management of HF should be optimal for at least three to six months followed by repeat clinical evaluation including echocardiography before consideration of mitral valve intervention [6]. (See "Overview of the management of heart failure with reduced ejection fraction in adults" and "Primary pharmacologic therapy for heart failure with reduced ejection fraction" and "Secondary pharmacologic therapy for heart failure with reduced ejection fraction" and "Treatment and prognosis of heart failure with mildly reduced ejection fraction".)

For patients with HF with LVEF ≤50 percent and at least moderate to severe secondary (3+) MR with persistent symptoms despite optimized management of HF with anatomy amenable to transcatheter edge-to-edge repair (TEER), we suggest TEER. TEER may not be appropriate when life expectancy with intervention is less than one year or when comorbidities limit the likelihood of improvement in the patient's quality of life. (See "Transcatheter edge-to-edge mitral repair" and 'For ventricular secondary MR' below.)

•Atrial secondary MR – For patients with at least moderate to severe chronic secondary MR, dilated left atria, and LVEF ≥50 percent and symptomatic HF despite optimum evidence-based management (pharmacologic therapy plus CRT, as indicated) and appropriate anatomy for TEER, we suggest TEER. (See 'For atrial secondary MR' below and "Transcatheter edge-to-edge mitral repair".)

●Patients with severe chronic secondary MR undergoing cardiac surgery for a concurrent condition – For patients with severe secondary MR in the setting of CAD undergoing cardiac surgery for another indication (eg, coronary artery bypass graft surgery or surgical aortic valve replacement), we suggest concomitant mitral valve replacement with chordal sparing rather than mitral valve repair. (See 'Concurrent mitral valve surgery and CABG' below and 'Replacement or repair' below.)

Quantification of MR — Accurate quantification of MR is a key requirement for identifying appropriate candidates with secondary MR for TEER. Severe secondary MR is generally identified by an effective regurgitant orifice area (EROA) ≥0.40 cm², a regurgitant volume ≥60 mL, or a regurgitant fraction ≥50 percent (table 1) [1,2]. The criterion of a regurgitant fraction >50 percent is generally preferred in the following settings: in patients with secondary MR with a crescentic/elliptical shaped proximal convergence area, since two-dimensional (2D) transesophageal echocardiography (TEE) may underestimate the EROA; and in patients with low flow states since the regurgitant volume may be lower in this setting. (See "Clinical manifestations and diagnosis of chronic mitral regurgitation", section on 'Identifying the severity of MR'.)

OUTCOMES OF MITRAL VALVE INTERVENTION

Transcatheter edge-to-edge repair

For ventricular secondary MR — Most patients with secondary MR have LV systolic dysfunction.

TEER versus medical therapy — Two randomized controlled trials assessing the efficacy of transcatheter edge-to-edge repair (TEER) using the MitraClip compared with continued medical therapy alone in patients with secondary MR yielded disparate results [7,8].

●The COAPT trial enrolled 614 patients with moderate to severe or severe secondary MR and an LVEF of 20 to 50 percent with New York Heart Association (NYHA) class II, III, or IVa (ambulatory) HF despite maximal medical therapy [7,9].

•One or more MitraClip devices (mean 1.7 clips; range one to four) were implanted in 98 percent of patients in whom implantation was attempted. At discharge, the MR grade was 1+ or less in 82.3 percent in the intervention group.

•The postprocedural 30-day mortality rate was 2.3 percent, and the rate of stroke was 0.7 percent. The rate of freedom from device-related complications at 12 months was 96.6.

•TEER significantly reduced mortality compared with control medical therapy at two years (29.1 versus 46.1 percent) [7] and at five years (57.3 versus 67.2 percent) [9].

•While a lower rate of hospitalization for HF with TEER was evident within 30 days after treatment, a significantly lower mortality rate with TEER emerged more than one year after the intervention [7]. The annualized rate of hospitalization for HF through five years was 33.1 percent per year in the device group and 57.2 percent per year in the control group (hazard ratio [HR] 0.53; 95% CI 0.41 to 0.68) [9].

•All device-specific safety events (complications) occurred within 30 days after the procedure, occurring in 1.4 percent of patients undergoing TEER [9].

●The smaller MITRA-FR randomized trial enrolled 304 patients with moderate to severe (2+ to 4+) secondary MR, an LVEF of 15 to 40 percent, and symptomatic HF [8]. The trial did not require optimization of medical therapy for HF prior to enrollment.

•One or more MitraClip devices (one device in 45.7 percent, two devices in 44.9 percent, three or more in 9.4 percent) were implanted in 96 percent of patients in whom implantation was attempted. At discharge, the MR grade was 1+ or less in 75.6 percent in the intervention group.

•Periprocedural complications were observed in 14.6 percent of patients.

•At 12 months, there was no significant difference in the rate of all-cause mortality between the intervention and control groups (24.3 versus 22.4 percent; HR 1.11, 95% CI 0.69-1.77) or in the rate of unplanned hospitalization for HF (48.7 versus 47.4 percent; HR 1.13, 95% CI 0.81-1.56).

•The rate of the composite outcome of all-cause mortality or unplanned hospitalization for HF was also similar in the two groups (54.6 versus 51.3 percent; odds ratio 1.16, 95% CI 0.73-1.84).

•The frequency of serious adverse events at one year was similar in the two groups (82.2 and 79.6 percent).

Compared with the MITRA-FR trial, the COAPT trial was larger, included longer follow-up, and included patients with higher B-type natriuretic peptide levels (mean 1043 versus 800 ng/L), smaller LV end-diastolic volume, and more severe MR (mean effective regurgitant orifice area [EROA] 0.41 versus 0.31 cm², although this measure has limited reliability in secondary MR [10]) (table 1) [11,12]. These differences are potential causes for the differences in trial results. These findings suggest that TEER may reduce hospitalizations for HF and mortality for selected patients with moderate to severe to severe (3+ to 4+; mean EROA = 0.41 cm²) secondary MR with HF symptoms despite optimum evidence-based therapy [7] but not in patients with moderate (2+, mean EROA = 0.31 cm²) secondary MR [8].

Role of CRT prior to TEER — An observational study of patients with HF with LVEF ≤35 percent and criteria for cardiac resynchronization therapy (CRT) supports optimization of HF management including CRT (if appropriate) prior to TEER [13]. Among 126 patients eligible for CRT, 70 patients did not receive CRT prior to TEER and 56 patients received CRT prior to TEER. Mortality at one year was lower in patients receiving CRT prior to TEER than in those not receiving CRT prior to TEER (25 versus 43 percent). On multivariable analysis, among patients with a class I (strong) indication for CRT, lack of CRT prior for TEER was associated with higher risk of mortality or HF hospitalization at one year (HR 2.36, 95% CI 1.1-4.98).

For atrial secondary MR — A minority of patients with secondary MR have atrial secondary MR, which is related to atrial dilation and often associated with atrial fibrillation. Data on TEER outcomes are more limited in this patient population. A study of data from the International EuroSMR registry on 126 patients with atrial secondary MR (largely 3+ or 4+) undergoing TEER found that these patients frequently have successful procedures (87.2 percent with MR ≤2+ at discharge) and symptomatic improvement (NYHA functional class III/IV from 86.5 percent at baseline to 36.6 percent at follow-up) [14]. The estimated two-year survival rate for patients with atrial secondary MR was 70.4 percent, which was similar to the survival rate for patients with ventricular secondary MR. Predictors of two-year mortality included NYHA functional class and right ventricular dysfunction. Most patients (78.6 percent) with atrial secondary MR had atrial fibrillation at baseline.

Mitral valve surgery — Mitral valve surgery is a potential option for selected patients with severe secondary MR who have persistent symptoms despite optimum therapy for HF and who have anatomic limitations that leave them ineligible for TEER.

Isolated mitral surgery — Limited data are available on the efficacy and safety of isolated mitral valve surgery (without coronary artery bypass graft surgery [CABG]) for secondary MR [15]. There are no randomized trials of medical versus surgical therapy for secondary MR or of revascularization alone versus revascularization plus mitral surgery for the subgroup of patients with ischemic MR.

In small, early observational studies, mitral valve repair in patients with dilated or ischemic cardiomyopathy led to a reduction in end-diastolic volume and improvements in LVEF, cardiac output, and NYHA functional class [16-18]. There are only limited long-term observational data regarding surgical mitral valve repair for severe HF associated with secondary severe MR [17-19]. In a study of 419 patients with LVEF ≤30 percent and at least moderate to severe MR, surgical mitral valve repair was performed in 126 (30 percent) [19]. The majority of patients had CAD. Thirty-day postoperative mortality was 4.8 percent. At long-term follow-up (to >2000 days), there was no significant difference in mortality between patients who did or did not undergo mitral valve repair (48 versus 38 percent with medical therapy alone) or in the combined endpoint of death, implantation of an LV assist device, or urgent heart transplantation (49 versus 41 percent). Baseline characteristics in the two groups were largely similar, although confounding by indication (eg, operating on sicker patients) could not be completely excluded [20].

Concurrent mitral valve surgery and CABG — The rationale for performing mitral valve surgery concurrently with CABG is that CABG alone is less likely to reduce MR, and persistent (and progressive) MR may lead to worse outcomes. However, the results of studies of the impact of mitral valve surgery (generally mitral valve repair) at the time of CABG for patients with ischemic MR have been mixed. Although mitral valve repair at the time of CABG reduces MR compared with CABG alone, the data suggest that an improvement in symptoms and exercise tolerance is possible, but it does not appear that there is a survival benefit.

A randomized trial, as well as some observational studies, found no improvement in symptoms or risk of mortality from the addition of mitral valve surgery to CABG compared with CABG alone [21-24]. In the largest randomized trial, 301 patients with moderate ischemic MR were randomly assigned to CABG alone or CABG combined with mitral valve repair [24,25]. At one- and two-year follow-up, the degree of reverse remodeling (measured as LV end-systolic volume index), readmission rates, and mortality rates (7.3 versus 6.7 percent at one year; 10.6 versus 10 percent at two years) were similar in the two groups. In the combined procedure group, postoperative moderate or severe MR was less frequent (11.2 versus 32.3 percent in the CABG alone group at two years), but the combined procedure group had a longer bypass time, longer hospital stay after surgery, and more frequent neurologic events and supraventricular arrhythmias than the CABG alone group. Quality of life scores improved similarly in the two groups except that the Duke Activity Status Index was significantly better in the combined procedure group at two years. Longer follow-up is needed to determine whether the reduction in MR leads to a long-term clinical benefit.

In contrast, two earlier, smaller randomized trials and an observational study suggested a functional benefit from concomitant mitral valve surgery at the time of CABG [26-28], and an observational study suggested a survival benefit from the addition of mitral valve repair to CABG [29]. A randomized trial included 102 patients with moderate (2+) ischemic MR who underwent CABG plus mitral valve repair or CABG alone [27]. Mortality rates at five years were not significantly different for the two groups (6.3 versus 11.2 percent), but the functional status of patients undergoing mitral valve repair was significantly better, with fewer patients with NYHA functional class II or greater (15.5 versus 43.7 percent). Similarly, the Randomized Ischemic Mitral Evaluation (RIME) multicenter randomized trial of 73 patients with moderate ischemic MR found that the addition of mitral annuloplasty to CABG did not affect mortality rates but improved functional capacity (peak oxygen consumption) and LV reverse remodeling [28].

CHOICE OF MITRAL SURGICAL PROCEDURE — For patients with secondary MR undergoing mitral valve surgery, a choice is made between mitral valve replacement or repair. Options for mitral valve replacement include bioprosthetic and mechanical valves.

Replacement or repair — For patients undergoing mitral valve surgery for secondary MR, the choice of procedure (surgical mitral valve repair or replacement) varies with the cause of MR. These recommendations are based upon a randomized trial comparing surgical mitral valve repair with mitral valve replacement for secondary MR.

●For patients with ischemic MR who undergo mitral valve surgery (which usually occurs with concurrent coronary artery bypass graft surgery [CABG]), we suggest mitral valve replacement with chordal sparing, rather than surgical mitral valve repair.

●For patients with nonischemic MR who undergo mitral valve surgery, we suggest mitral valve replacement with chordal sparing unless valve anatomy is favorable for surgical mitral repair and intraoperative TEE demonstrates minimal residual MR after repair.

For ischemic MR — The available evidence suggests that for patients with severe ischemic MR, survival is similar following mitral valve replacement with chordal sparing and surgical mitral valve repair. However, recurrent MR is much more frequent following surgical mitral valve repair. A randomized trial enrolling 251 patients with severe ischemic MR found that surgical mitral valve repair resulted in a higher rate of cardiovascular admission and a borderline significantly higher rate of HF-related adverse events [30,31]:

●There was no difference in survival at one year (85.7 versus 82.4 percent) [30] and at two years (81.0 versus 76.8 percent) [31].

●The rate of recurrent moderate or severe MR was significantly higher in patients undergoing repair (32.6 versus 2.3 percent at one year; 58.8 versus 3.8 percent at two years).

●The rate of a composite of major adverse cardiac or cerebrovascular events was similar in the two groups (42.1 and 42.4 percent at two years). However, the repair group had more serious HF events (borderline significant) at two years (24.0 versus 15.2 per 100 patient-years, p = 0.05).

●The treatment groups had similar overall readmission rates, but the rate of readmission for cardiovascular causes was significantly higher in the repair group (48.3 versus 32.2 per 100 patient-years).

Of note, the results of this randomized trial contradict findings from earlier studies, including two meta-analyses of observational studies that suggested improved short- and long-term survival with surgical mitral valve repair [32,33]. The differences in results may have been caused by greater use of chordal-sparing mitral valve replacement in the trial and/or by inadequate adjustment for baseline difference in the observational studies.

The rate of late recurrent MR (moderate or severe) following surgical mitral valve repair is as high as 58.8 percent [30,31,34,35]. Adverse LV remodeling contributes to recurrent MR because ring annuloplasty reduces tethering at the annular but not the ventricular end [36]. The time course of recurrent MR was illustrated in a review of 585 patients with ischemic MR [35]. The rate of moderate to severe MR was 28 percent at six months and remained stable thereafter. Although the rate of recurrent MR was high, the five-year rate of requiring mitral valve replacement was only 3 percent. There are at least three explanations for the low rate of repeat surgery at five years: The degree of MR may have limited importance compared with the underlying cardiovascular disease; almost one-half of patients died within five years, which limited the number of patients in whom reoperation could be performed; and surgeons may be reluctant to perform a repeat operation in this older, high-risk population.

Preoperative clinical and echocardiographic parameters may help identify patients at greatest risk for recurrent MR. A study of 365 patients undergoing surgical mitral valve repair for ischemic MR found three independent predictors of annuloplasty failure: a larger mitral annular diameter, higher tethering area, and greater MR severity [37]. Specific risk factors are associated with worse outcomes in patients undergoing mitral valve repair. A study of mitral valve repair for secondary MR (80 percent ischemic) found that mitral valve coaptation depth and markers of right ventricular dysfunction (tricuspid annular plane systolic excursion ≤12 mm and tricuspid annular peak systolic velocity ≤10 cm/s) were predictors of worse early and five-year mortality [38].

For nonischemic secondary MR — An observational study of 112 patients with moderate or severe nonischemic secondary MR found that one-, three-, and five-year survival rates were higher in patients undergoing surgical mitral valve repair than in patients treated only medically (96.6 versus 81.2, 91.8 versus 71.9, and 77.4 versus 65.1 percent) [39]. LVEF <41.5 percent was an independent predictor of mortality and unplanned hospitalization for HF.

Choice of prosthetic valve — For patients with an indication for mitral valve surgery who undergo valve replacement, the choice of mechanical versus bioprosthetic valve should follow guidelines for valve choice based on patient age, risks of long-term anticoagulation, and patient preferences (table 2) [1]. Given the limited life expectancy of many patients with secondary MR, it is reasonable to consider a bioprosthetic valve rather than mechanical prosthetic valve when life expectancy is shorter than the expected lifespan of a bioprosthetic valve. In addition, preserving the subvalvular apparatus is less technically demanding and associated with fewer valve-related complications when a bioprosthesis is used. Finally, the mitral valve-in-valve procedure is an option for degenerating bioprosthetic mitral valves. (See "Choice of prosthetic heart valve for surgical aortic or mitral valve replacement" and "Mechanical prosthetic valve thrombosis or obstruction: Clinical manifestations and diagnosis" and "Surgical procedures for severe chronic mitral regurgitation", section on 'Chordal preservation'.)

OTHER INTERVENTIONS

Coronary revascularization — For patients with secondary MR, standard recommendations for management of CAD and coronary revascularization apply (including activity-limiting angina despite maximum medical therapy, significant left main CAD, or multivessel CAD with a reduction of LVEF and a large area of potentially ischemic myocardium). Revascularization may also reduce the severity of MR if a significant area of stunned or hibernating (ischemic yet viable) myocardium is present. (See "Chronic coronary syndrome: Overview of care" and "Revascularization in patients with stable coronary artery disease: Coronary artery bypass graft surgery versus percutaneous coronary intervention" and "Treatment of ischemic cardiomyopathy".)

Revascularization in patients with chronic ischemic MR (without valve repair) is less likely to reduce MR than revascularization in the setting of acute ischemic MR. Observational studies suggest that reperfusion (by primary percutaneous coronary intervention [PCI] or thrombolysis) in patients with acute inferior or posterior (inferolateral) ST-elevation MI substantially reduces the incidence of moderate to severe ischemic MR (eg, 2.5 versus 11.1 percent in patients not receiving reperfusion) [40-42]. Revascularization reduces the severity of chronic ischemic MR in some, but not all, patients, as illustrated by the following observations:

●In a series of 136 patients with moderate to severe ischemic MR undergoing coronary artery bypass graft surgery (CABG), 40 percent continued to have moderate to severe (3+ to 4+) MR, 51 percent had some improvement to moderate (2+) MR, and 9 percent had no or mild (0 to 1+) MR [43].

●Preoperative evaluation may help identify patients in whom ischemic MR is likely to improve following CABG. At one-year follow-up of 135 patients with moderate ischemic MR who had undergone CABG, 57 had no or mild MR, 64 patients had no change or worse MR, and 14 had died [44]. The majority (93 percent) of surviving patients with large extent of viable myocardium (≥5 segments by single-photon emission computed tomography) and lack of dyssynchrony of segments underlying the papillary muscles showed reduced MR, while only 34 and 18 percent of patients with <5 viable segments and dyssynchrony, respectively, showed improvement in MR. The group with decreased MR also had a marked improvement in LVEF and a decrease in LV volumes, consistent with the mechanism of improvement being reperfusion of viable myocardium. Patients with a decrease in MR demonstrated symptomatic improvement and improved survival compared with those without improvement in MR.

Observational data suggest that revascularization may improve survival in patients with ischemic MR with a broad range of LVEFs. In a retrospective study that included 4989 patients with moderate or severe ischemic MR with mean LVEF 46 percent (25^th to 75^th percentile of 30 to 60 percent), 36 percent received medical therapy alone, 26 percent underwent PCI, 33 percent underwent CABG, and 5 percent underwent CABG plus surgical mitral valve repair or replacement [45]. During median follow-up of 5.4 years, significantly lower mortality compared with medical therapy alone was observed in patients treated with CABG (adjusted hazard ratio [HR] 0.56, 95% CI 0.51-0.62), CABG plus surgical mitral valve repair or replacement (adjusted HR 0.69, 95% CI 0.57-0.82), or PCI (adjusted HR 0.83, 95% CI 0.76-0.92). However, these results do not establish a clinical benefit, given the risk of residual bias despite propensity score adjustment. Other studies of the impact of mitral valve surgery in patients undergoing CABG are discussed separately. (See 'Concurrent mitral valve surgery and CABG' above.)

Interventions for advanced heart failure — Management of refractory HF, including the role of interventions such as mechanical circulatory support and cardiac transplantation, is discussed separately. (See "Management of refractory heart failure with reduced ejection fraction" and "Heart transplantation in adults: Indications and contraindications".)

Investigational approaches — Given the limited durability of surgical mitral valve repair, a variety of approaches to eliminate leaflet tethering and improve mitral leaflet coaptation have been studied. These include subvalvular procedures (such as chordal cutting and papillary muscle repositioning, posterior leaflet extension, and variations in the annuloplasty ring) [34,46-49]. The effect of these mitral valve repair techniques on clinical outcomes has not been established.

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

●Role of transcatheter edge-to-edge mitral repair for secondary (functional) mitral regurgitation

•Ventricular secondary MR – For symptomatic patients with heart failure (HF) with left ventricular ejection fraction (LVEF) ≤50 percent and secondary mitral regurgitation (MR), the mainstay of management is optimized management of HF (pharmacologic therapy plus cardiac resynchronization therapy [CRT], as indicated). Evidence-based management of HF should be optimal for three to six months followed by repeat clinical evaluation including echocardiography before consideration of mitral valve intervention. (See "Chronic secondary mitral regurgitation: General management and prognosis" and "Overview of the management of heart failure with reduced ejection fraction in adults" and "Treatment and prognosis of heart failure with mildly reduced ejection fraction".)

For patients with HF with LVEF <50 percent and at least moderate to severe (3+) secondary MR with persistent symptoms despite optimized HF management with anatomy amenable to transcatheter edge-to-edge repair (TEER), we suggest TEER (Grade 2B).

TEER (or mitral valve surgery) may not be appropriate when life expectancy with intervention is less than one year or when comorbidities limit the likelihood of improvement in the patient's quality of life. (See "Transcatheter edge-to-edge mitral repair".)

•Atrial secondary MR – For patients with HF and at least moderate to severe (3+) chronic secondary MR, dilated left atria, and LVEF ≥50 percent and persistent symptoms despite optimum management (pharmacologic therapy plus CRT, as indicated) and appropriate anatomy for TEER, we suggest TEER (Grade 2C). (See 'For atrial secondary MR' above.)

●Role of mitral valve surgery

•For selected patients who are not candidates for TEER – Mitral valve surgery is a potential option for selected patients with severe secondary MR with persistent symptoms despite optimum therapy for HF and who have mitral anatomy that is not suitable for TEER. (See 'Choice of mitral surgical procedure' above.)

•For severe secondary MR plus another indication for cardiac surgery – For patients with severe secondary MR in the setting of coronary artery disease (CAD) undergoing cardiac surgery for another indication (eg, coronary artery bypass graft surgery [CABG] or surgical aortic valve replacement), we suggest concomitant mitral valve replacement with chordal sparing rather than mitral valve repair. (Grade 2B). (See 'Concurrent mitral valve surgery and CABG' above and 'Replacement or repair' above.)

●Coronary revascularization - For patients with secondary MR, standard recommendations for management of CAD and coronary revascularization apply. Revascularization may also reduce the severity of MR if a significant area of stunned or hibernating (ischemic yet viable) myocardium is present. Revascularization in patients with chronic ischemic MR (without valve repair) is less likely to reduce MR than revascularization in the setting of acute ischemic MR. (See "Chronic coronary syndrome: Overview of care" and "Revascularization in patients with stable coronary artery disease: Coronary artery bypass graft surgery versus percutaneous coronary intervention" and "Treatment of ischemic cardiomyopathy".)