Coronary artery bypass surgery with or without mitral valve annuloplasty in moderate functional ischemic mitral regurgitation: final results of the Randomized Ischemic Mitral Evaluation (RIME) trial

Percutaneous coronary intervention for acute myocardial infarction with mitral regurgitation

Ischemic mitral regurgitation (IMR) is a common complication of acute myocardial infarction (AMI). Current evidences suggest that revascularization of the culprit vessels with percutaneous coronary artery intervention (PCI) or coronary artery bypass grafting can be beneficial for relieving IMR. A 2.5-year follow-up data of a 61-year-old male patient with ST-segment elevation AMI complicated with IMR showed that mitral regurgitation area increased five days after PCI, and decreased to lower steady level three months after PCI. This finding suggest that three months after PCI might be a suitable time point for evaluating the possibility of IMR recovery and the necessity of surgical intervention of the mitral valve for AMI patient.

Mitral valve repair for ischemic moderate mitral regurgitation in patients undergoing coronary artery bypass grafting

Objectives:

To investigate whether mitral valve repair (MVR) at the time of coronary artery bypass grafting (CABG) in patients with ischemic moderate mitral regurgitation (MR) and coronary artery disease could improve short- and mid-term postoperative outcomes.

Methods:

Between March 2013 and December 2015, 90 patients with moderate ischemic MR underwent first-time CABG in Bursa Yuksek Ihtisas Training and Research Hospital, Bursa, Turkey. Out of 90 patients, 44 (48.9%) underwent combined CABG+MVR. The remaining 46 (51.1%) underwent CABG alone. Ventricular functions and effort capacities of patients in both groups were evaluated echocardiographically and clinically in the preoperative period, and in the first postoperative year.

Results:

Postoperative regurgitant volume changes according to preoperative values were -24.76±19 ml/beat in the combined CABG+MVR group, and -8.70±7.2 ml/beat in the CABG alone group (p=0.001). The change of vena contracta width was -3.40±0.2 mm in the combined CABG+MVR group whereas in the CABG alone -1.45±0.7 mm (p=0.019). The changes of left ventricular end-systolic volume index were -30.77±25.9 ml/m² in the combined CABG+MVR group and -15.6±9.4 ml/m² in the CABG alone group (p=0.096). Ejection fraction changes in the combined CABG+MVR group was +1.51±5.3% and in the CABG alone group was +1.15±4.3%. No statistically significant difference was found between both groups (p=0.604). Preoperative New York Heart Association class values in the combined CABG+MVR group was 2.18±0.45, and in the CABG alone group was 2.13±0.54.

Conclusions:

Moderate MR in patients undergoing CABG affects the outcome adversely and it does not reliably improve after CABG alone. Therefore, patients with ischemic moderate MR should undergo simultaneous MVR at the time of CABG.

Two-Year Outcomes of Surgical Treatment of Moderate Ischemic Mitral Regurgitation

BACKGROUND

In a trial comparing coronary-artery bypass grafting (CABG) alone with CABG plus mitral-valve repair in patients with moderate ischemic mitral regurgitation, we found no significant difference in the left ventricular end-systolic volume index (LVESVI) or survival after 1 year. Concomitant mitral-valve repair was associated with a reduced prevalence of moderate or severe mitral regurgitation, but patients had more adverse events. We now report 2-year outcomes.

METHODS

We randomly assigned 301 patients to undergo either CABG alone or the combined procedure. Patients were followed for 2 years for clinical and echocardiographic outcomes.

RESULTS

At 2 years, the mean (±SD) LVESVI was 41.2±20.0 ml per square meter of body-surface area in the CABG-alone group and 43.2±20.6 ml per square meter in the combined-procedure group (mean improvement over baseline, -14.1 ml per square meter and -14.6 ml per square meter, respectively). The rate of death was 10.6% in the CABG-alone group and 10.0% in the combined-procedure group (hazard ratio in the combined-procedure group, 0.90; 95% confidence interval, 0.45 to 1.83; P=0.78). There was no significant between-group difference in the rank-based assessment of the LVESVI (including death) at 2 years (z score, 0.38; P=0.71). The 2-year rate of moderate or severe residual mitral regurgitation was higher in the CABG-alone group than in the combined-procedure group (32.3% vs. 11.2%, P<0.001). Overall rates of hospital readmission and serious adverse events were similar in the two groups, but neurologic events and supraventricular arrhythmias remained more frequent in the combined-procedure group.

CONCLUSIONS

In patients with moderate ischemic mitral regurgitation undergoing CABG, the addition of mitral-valve repair did not lead to significant differences in left ventricular reverse remodeling at 2 years. Mitral-valve repair provided a more durable correction of mitral regurgitation but did not significantly improve survival or reduce overall adverse events or readmissions and was associated with an early hazard of increased neurologic events and supraventricular arrhythmias. (Funded by the National Institutes of Health and Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00806988.).

Coronary Atherosclerosis: Pathophysiologic Basis for Diagnosis and Management

Coronary atherosclerosis is a long lasting and continuously evolving disease with multiple clinical manifestations ranging from asymptomatic to stable angina, acute coronary syndrome (ACS), heart failure (HF) and sudden cardiac death (SCD). Genetic and environmental factors contribute to the development and progression of coronary atherosclerosis. In this review, current knowledge related to the diagnosis and management of coronary atherosclerosis based on pathophysiologic mechanisms will be discussed. In addition to providing state-of-the-art concepts related to coronary atherosclerosis, special consideration will be given on how to apply data from epidemiologic studies and randomized clinical trials to the individual patient. The greatest challenge for the clinician in the twenty-first century is not in absorbing the fast accumulating new knowledge, but rather in applying this knowledge to the individual patient.

Meta-analysis of concomitant mitral valve repair and coronary artery bypass surgery versus isolated coronary artery bypass surgery in patients with moderate ischaemic mitral regurgitation

Ischaemic mitral regurgitation (IMR) is a complication of coronary artery disease with normal chordal and leaflet morphology. Controversy surrounds the issue of appropriate surgical management of moderate IMR. With the present meta-analysis, we aimed to determine whether the addition of mitral valve (MV) repair to coronary artery bypass grafting (CABG) improved clinical outcome over CABG alone in patients with moderate IMR. Databases were searched for studies reporting on clinical outcomes after CABG and MV repair or CABG alone for moderate IMR. Clinical end-points were operative mortality, survival, New York Heart Association (NYHA) class ≥2 and MR grade ≥2 at last follow-up. A total of five observational and four randomized controlled trials (RCTs) were identified. The mean follow-up was 2.7 years. An analysis of all studies revealed increased operative risk in the concomitant CABG and MV repair group {risk ratio [RR] 2.02 [95% confidence interval (CI) 1.15, 3.56], P = 0.01, I(2) = 0%}. However, an analysis of RCTs only showed that the operative risk was equivalent [RR 1.05 (95% CI 0.34, 3.30), P = 0.93, I(2) = 0%]. Pooled hazard ratio (HR) on survival did not favour either procedure [all studies: HR 1.08 (95% CI 0.77, 1.50), P = 0.66, I(2) = 0%; RCTs only: HR 0.89 (95% CI 0.47, 1.70), P = 0.73, I(2) = 0%]. The incidence of exercise intolerance quantified as NYHA class ≥2 was similar between groups (all studies: RR 0.72 (95% CI 0.42, 1.24), P = 0.24, I(2) = 77%; RCTs only: RR 0.61 (95% CI 0.24, 1.55), P = 0.30, I(2) = 83%]. Risk of residual MR grade ≥2 was higher in the CABG only group [all studies: RR 0.30 (95% CI 0.16, 0.60), P < 0.001, I(2) = 83%; RCTs only: RR 0.20 (95% CI 0.04, 0.90), P = 0.04, I(2) = 72%]. There is neither increased operative mortality nor survival benefit associated with concomitant CABG and MV repair for IMR of moderate degree over CABG alone. Further studies with long-term follow-up data and sub-group analyses of current data are needed to define a subset of patients whose survival and functional status may improve with the concomitant MV repair.

Year in review: mitral valve surgery

PURPOSE OF REVIEW

In the past year, there has been progress on several fronts in the field of mitral valve surgery and intervention. Here, we review key publications regarding the surgical and transcatheter management of mitral valve disease.

RECENT FINDINGS

This past year heralded the publication of the 2014 American Heart Association (AHA)/American College of Cardiology (ACC) Guidelines for the Management of Patients With Valvular Heart Disease. Regarding degenerative mitral regurgitation, low risk of operative mortality and data demonstrating clinical benefit for early surgery are prompting renewed calls for early intervention before guideline-based triggers. For functional mitral regurgitation, the precise roles of chordal-sparing replacement versus repair and the optimal management of moderate disease at the time of surgical revascularization are unclear. Sternal-sparing minimally invasive mitral valve surgery has become a mature procedure in experienced centers and offers comparable surgical morbidity and mortality with superior cosmesis and faster return to baseline function. Transcatheter interventions for mitral regurgitation continue to undergo development and testing. Mounting experience and ongoing clinical trials with the MitraClip endovascular edge-to-edge repair device will provide important data on the optimal target population for this device.

SUMMARY

This past year has seen important advances in the surgical treatment of degenerative and functional mitral regurgitation as well as continued refinement of transcatheter interventions.

CTS Trials Network: A paradigm shift in the surgical treatment of moderate ischemic mitral regurgitation?

The Cardiothoracic Surgery Trials Network has reported results of the one-year follow up of their randomized trial "Surgical Treatment of Moderate Ischemic Mitral Regurgitation". They studied 301 patients with moderate ischemic mitral regurgitation (IMR) undergoing coronary artery bypass grafting (CABG) with or without mitral repair with the primary end-point of change in left ventricular end-diastolic volume index (LVEDVI) at one year and multiple clinical and echocardiographic secondary endpoints. Although their results were against repairing the mitral valve, the debate on surgical management of moderate IMR remains unsettled.

The Evolving Role of Percutaneous Mitral Valve Repair

BACKGROUND

Mitral regurgitation (MR) is the second leading cause of valvular heart disease in the United States behind aortic stenosis. The percutaneous repair of the mitral valve (MitraClip, Abbott, Inc.) has been approved in the United States since 2013 as an alternative to traditional mitral valve surgery. However, many questions are left unanswered about when to perform this procedure and whom to perform it on.

METHODS

We reviewed major published literature on the MitraClip from 2003-2016 to help guide clinical decision-making. A PubMed search was conducted using the phrase "mitraclip" or "percutaneous mitral valve repair" to identify relevant articles pertaining to the clip as well as surgical valve repair.

RESULTS

The clinical trials EVEREST I and EVEREST II (Endovascular Valve Edge-to-Edge Repair Study) demonstrated the safety and efficacy of the MitraClip but did not prove its superiority to surgical repair in the population studied. Numerous subsequent registries have suggested that the success of the MitraClip varies with the patient population studied. The currently enrolling Cardiovascular Outcomes for Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional MR (COAPT) trial hopes to answer some of these questions.

CONCLUSION

The MitraClip is a new and exciting technology for percutaneously treating disease processes traditionally managed with surgery. The future of the clip and its patient population is dependent on further studies.

Impact of additive mitral valve surgery to coronary artery bypass grafting on mortality in patients with coronary artery disease and ischaemic mitral regurgitation: a systematic review and meta-analysis of randomized trials and observational studies

Aims

Treatment of ischaemic mitral regurgitation (IMR) remains controversial. While IMR is associated with worse outcomes, randomized controlled trials (RCTs) and observational studies provided conflicting evidence regarding the benefit of mitral valve replacement (MVR) or repair (MVr) in addition to coronary artery bypass grafting (CABG). We conducted a meta-analysis incorporating data from published RCTs and observational studies comparing CABG vs. CABG + MVR/MVr.

Methods and results

We searched PubMed, MEDLINE, Embase, Ovid, and Cochrane for RCTs and observational studies comparing CABG (Group 1) vs. CABG + MVR/MVr (Group 2). Outcome was 30-day and 1-year mortality after surgical intervention. Mantel-Haenszel odds ratio (OR) was calculated using random-effects meta-analysis for the outcome. Heterogeneity was assessed by I2 statistics. Four RCTs and 11 observational studies met the inclusion criteria (5781 patients, 507 in RCTs, 5274 in observational studies). Group 1 vs. 2 weighted mean left ventricular ejection fraction in RCTs and combined RCTs/observational studies was 41.5 ± 12.3 vs. 40.3 ± 10.4% ( P -value = 0.24) and 45.5 ± 7.2 vs. 38 ± 10% ( P -value < 0.001), respectively. In RCTs, there was no difference in 30-day [OR: 0.95, 95% confidence interval (95% CI): 0.30-3.08, P = 0.94] or 1-year (OR: 0.90, 95% CI: 0.43-1.87, P = 0.78) mortality, respectively. For combined RCTs/observational studies, there was no difference in mortality at 30 days (OR: 0.67, 95% CI: 0.43-1.04, P = 0.08) or at 1 year (OR: 0.90, 95% CI: 0.7-1.15, P = 0.39).

Conclusion

In a meta-analysis of RCTs and observational studies of IMR patients, the addition of MVR/MVr to CABG did not improve survival.

Short-Term and Long-Term Survival After Revascularization with or without Mitral Valve Surgery of Patients with Ischemic Mitral Valve Regurgitation: A Meta-Analysis

BACKGROUND There is no consensus on whether mitral valve repair or replacement (MVRR) must be performed to treat ischemic mitral regurgitation (MVR) after myocardial infarction. Our objective in this study was to investigate the efficacy of coronary artery bypass grafting (CABG) combined with or without MVRR for the ischemic MVR. MATERIAL AND METHODS An article search was performed in OvidSP, PubMed, Cochrane Library, and Embase. In these articles, researchers compared the efficacy of CABG with or without MVRR in treating patients with ischemic MVR after acute coronary syndrome (ACS). We performed a meta-analysis to compare the differences in the short-term and long-term survival rates of patients treated with CABG only and those treated with both CABG and MVRR. Secondary outcomes were compared with the preoperative and postoperative degree of MVR, left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), and New York Heart Association (NYHA) class. RESULTS Out of the 1183 studies, we selected only 5 articles. A total of 3120 patients were enrolled; the CABG and MVRR group included 575 patients, while the CABG only group included 2545 patients. Long-term survival was higher in the CABG only group (hazard ratio [HR], 1.34; 95% confidence interval [CI] 1.15-1.58, P=0.003). Hospital mortality was similar in both the groups (odds ratio [OR], 2.54; 95% CI, 0.65-9.95; P=0.18). No differences were found in the degree of residual MVR, the mean of LVESV, LVEF, or NYHA class. CONCLUSIONS In patients with ischemic MVR, the short-term survival rate was similar in both groups. Moreover, there was no significant improvement in the long-term survival rates of patients treated with both CAG and MVRR.

New Insights in the Diagnosis and Treatment of Heart Failure

Cardiovascular disease is the leading cause of mortality in the US and in westernized countries with ischemic heart disease accounting for the majority of these deaths. Paradoxically, the improvements in the medical and surgical treatments of acute coronary syndrome are leading to an increasing number of “survivors” who are then developing heart failure. Despite considerable advances in its management, the gold standard for the treatment of end-stage heart failure patients remains heart transplantation. Nevertheless, this procedure can be offered only to a small percentage of patients who could benefit from a new heart due to the limited availability of donor organs. The aim of this review is to evaluate the safety and efficacy of innovative approaches in the diagnosis and treatment of patients refractory to standard medical therapy and excluded from cardiac transplantation lists.

Restrictive Mitral Annuloplasty Does Not Limit Exercise Capacity

BACKGROUND

Restrictive mitral annuloplasty is the preferred method of treating secondary mitral regurgitation. The use of small annuloplasty rings to reduce the high recurrence rates may result in mitral stenosis.

METHODS

Thirty-six patients who underwent restrictive mitral annuloplasty with Carpentier-Edwards classic 26 size ring underwent exercise echocardiography and ergospirometry. Resting catecholamines and N-terminal pro brain natriuretic peptide (NT-proBNP) levels were measured.

RESULTS

At the time of study, the median time from operation was 16.6 months (interquartile range, 8.5 to 43.3 months). Left ventricular end-systolic volume index (LVESVI) was 67 mL/m(2) (interquartile range, 25 to 92 mL/m(2)), and ejection fraction (EF) was 38.8% (interquartile range, 28.3% to 59.0%). Mitral gradients were higher at the leaflet tips than at the annular level. Continuous wave (CW) Doppler gradients at rest were 3.4 mmHg (interquartile range, 2.4 to 4.9 mmHg) mean and 9.5 mmHg (interquartile range, 7.0 to 14.7 mmHg) maximal. On exertion, they increased to 6.8 mmHg (interquartile range, 5.4 to 8.8 mmHg) (p = 0.001) and 19.7 mmHg (interquartile range, 12.8 to 23.3 mmHg) (p = 0.001), respectively. Maximal VO2 was 18.2 mL/kg/min (interquartile range, 16.3 to 21.5 mL/kg/min), VE/VCO2 slope was 31.1 (interquartile range, 26 to 34). Epinephrine level was 0.024 ng/mL (interquartile range, 0.0098 to 0.043 ng/mL), norepinephrine was 0.61 ng/mL (interquartile range, 0.41 to 0.95 ng/mL), and NT-proBNP was 303 pg/mL (interquartile range, 155 to 553 pg/mL). Maximal VO2 negatively correlated with resting norepinephrine level (r = -0.50, p = 0.003). VE/VCO2 slope positively correlated with NT-proBNP (r = 0.36, p = 0.004) and epinephrine (r = 0.36, p = 0.04) levels and with LV volumes (r = 0.51, p = 0.006) and was negatively correlated with LVEF (r = -0.52, p = 0.004). Neither maximal VO2 nor VE/VCO2 slope correlated with the highest mean (r = 0.24, p = 0.2, and r = -0.20, p = 0.3, respectively) and maximal (r = 0.13, p = 0.5, r = -0.20, p = 0.3, respectively) mitral gradients on exertion.

CONCLUSIONS

Restrictive mitral annuloplasty for secondary mitral regurgitation does result in a degree of mitral stenosis; however, primary heart disease seems more important for patient's exercise performance than the mitral stenosis resulting from using an undersized ring.

Managing Heart Failure Patients with Multivessel Disease - Coronary Artery Bypass Graft versus Percutaneous Coronary Intervention

The foundation of treatment for heart failure with reduced ejection fraction is guideline-directed medical treatment. However, surgical revascularisation offers improved survival and quality of life for patients with more extensive coronary disease and the greatest degree of left ventricular systolic dysfunction and remodelling. The most commonly considered surgical interventions for patients with heart failure with reduced ejection fraction are coronary artery bypass surgery, sometimes combined with surgical ventricular reconstruction and surgery for mitral regurgitation. In this review, the author considers the risks and benefits of coronary artery bypass graft versus percutaneous coronary intervention in the management of heart failure patients with multivessel disease.

Repair or observe moderate ischemic mitral regurgitation during coronary artery bypass grafting? Prospective randomized multicenter data

Ischemic mitral regurgitation (MR) is a common occurrence following myocardial infarction and its presence is associated with poor outcomes. The optimal treatment of ischemic MR is a matter of debate, especially for patients with moderate MR severity. Some authors advocate for isolated coronary artery bypass grafting (CABG) for patients with moderate MR, maintaining that reverse ventricular remodeling will reduce MR grade and its associated mortality risk, while others argue that a concomitant mitral valve repair (MVR) or replacement is superior. The Cardiothoracic Surgical Trials Network (CTSN) recently published the 1-year results of the Surgical Treatment of Moderate Ischemic Mitral Regurgitation study, a multicenter, randomized, controlled trial investigating the impact of MVR in addition to CABG compared to CABG alone in the treatment of moderate ischemic MR. Here, we have reviewed previous observational and prospective studies investigating moderate ischemic MR treatment as well as the results of the current CTSN randomized trial. Furthermore, we have summarized the current state of the available evidence and preview potential new information that will become available with planned subgroup analyses and further follow-up of enrolled patients in the recently completed CTSN trial.

Regurgitation Hemodynamics Alone Cause Mitral Valve Remodeling Characteristic of Clinical Disease States In Vitro

Mitral valve regurgitation is a challenging clinical condition that is frequent, highly varied, and poorly understood. While the causes of mitral regurgitation are multifactorial, how the hemodynamics of regurgitation impact valve tissue remodeling is an understudied phenomenon. We employed a pseudo-physiological flow loop capable of long-term organ culture to investigate the early progression of remodeling in living mitral valves placed in conditions resembling mitral valve prolapse (MVP) and functional mitral regurgitation (FMR). Valve geometry was altered to mimic the hemodynamics of controls (no changes from native geometry), MVP (5 mm displacement of papillary muscles towards the annulus), and FMR (5 mm apical, 5 mm lateral papillary muscle displacement, 65% larger annular area). Flow measurements ensured moderate regurgitant fraction for regurgitation groups. After 1-week culture, valve tissues underwent mechanical and compositional analysis. MVP conditioned tissues were less stiff, weaker, and had elevated collagen III and glycosaminoglycans. FMR conditioned tissues were stiffer, more brittle, less extensible, and had more collagen synthesis, remodeling, and crosslinking related enzymes and proteoglycans, including decorin, matrix metalloproteinase-1, and lysyl oxidase. These models replicate clinical findings of MVP (myxomatous remodeling) and FMR (fibrotic remodeling), indicating that valve cells remodel extracellular matrix in response to altered mechanical homeostasis resulting from disease hemodynamics.

Role of percutaneous mitral valve repair in the contemporary management of mitral regurgitation

Percutaneous mitral valve (MV) repair has been performed in over 20,000 patients worldwide. As clinical experience in this technique grows indications for its use are being defined. Mitral regurgitation (MR) encompasses a complex heterogeneous group and its treatment is governed by determining a clear understanding of the underlying aetiology. Surgical MV repair remains the gold standard therapy for severe MR. However in select groups of high-risk surgical patients, a percutaneous approach to MV repair is establishing its role. This review gives an overview of the published data in percutaneous MV repair and its impact on the contemporary management of MR.

Moderate mitral regurgitation at the time of coronary bypass surgery: repair or leave it?

PURPOSE OF REVIEW

Moderate ischemic mitral regurgitation (IMR) is a common finding in patients undergoing coronary artery bypass grafting (CABG). In this review, we summarize the current evidence on the optimal management of this condition.

RECENT FINDINGS

In recent years, several randomized clinical trials have assessed the impact of concomitant restrictive mitral annuloplasty at the time of CABG on reverse left ventricular remodeling, IMR reduction and clinical outcomes.

SUMMARY

Surgical revascularization alone is a conservative strategy that reduces IMR in a significant proportion of patients. Concomitant restrictive annuloplasty provides better relief of mitral regurgitation in the immediate postoperative period, at the cost of increased perioperative morbidity. The only major randomized trial on the issue of moderate IMR published to date showed no difference in reverse left ventricular remodeling at 1 year between these two approaches. There are insufficient data in the literature to support the routine addition of mitral valve repair to CABG in patients with moderate IMR.

Therapeutic decision-making for patients with fluctuating mitral regurgitation

Mitral regurgitation (MR) is a common, progressive, and difficult-to-manage disease. MR is dynamic in nature, with physiological fluctuations occurring in response to various stimuli such as exercise and ischaemia, which can precipitate the development of symptoms and subsequent cardiac events. In both chronic primary and secondary MR, the dynamic behaviour of MR can be reliably examined during stress echocardiography. Dynamic fluctuation of MR can also have prognostic value; patients with a marked increase in regurgitant volume or who exhibit increased systolic pulmonary artery pressure during exercise have lower symptom-free survival than those who do not experience significant changes in MR and systolic pulmonary artery pressure during exercise. Identifying patients who have dynamic MR, and understanding the mechanisms underlying the condition, can potentially influence revascularization strategies (such as the surgical restoration of coronary blood flow) and interventional treatment (including cardiac resynchronization therapy and new approaches targeted to the mitral valve).

Hypertrophic cardiomyopathy: a review

Hypertrophic cardiomyopathy (HCM) is a global disease with cases reported in all continents, affecting people of both genders and of various racial and ethnic origins. Widely accepted as a monogenic disease caused by a mutation in 1 of 13 or more sarcomeric genes, HCM can present catastrophically with sudden cardiac death (SCD) or ventricular arrhythmias or insidiously with symptoms of heart failure. Given the velocity of progress in both the fields of heart failure and HCM, we present a review of the approach to patients with HCM, with particular attention to those with HCM and the clinical syndrome of heart failure.

Influence of procedural differences on mitral valve configuration after surgical repair for functional mitral regurgitation: in which direction should the papillary muscle be relocated?

Background

After restrictive mitral annuloplasty (RMAP) for functional mitral regurgitation (MR), the MR frequently recurs. Papillary muscle relocation (PMR) should reduce the recurrence rate. We assessed the influence of procedural differences in PMR on the postoperative mitral valve configuration.

Methods

Thirty-nine patients who underwent mitral valve repair for functional MR were enrolled. In limited tethering cases, RMAP alone was performed (RMAP group; n = 23). In severe tethering cases, in addition to RMAP, bilateral papillary muscles were relocated in the direction of the posterior annulus (posterior PMR group; n = 10) or anterior annulus (anterior PMR group; n = 6). We performed pre- and postoperative transthoracic echocardiographic studies, introducing a new index, mitral inflow angle (MIA), to assess the diastolic mitral leaflet excursion. MIA was measured as the angle between the mitral annular plane and the bisector of the anterior and posterior leaflets.

Results

Postoperative MR grade was significantly reduced in each group (P < 0.001). Follow-up echocardiography showed recurrent MR in 13% of the patients in RMAP group. In contrast, no recurrent MR was observed in either the anterior PMR or the posterior PMR group. After surgery, MIA was significantly reduced in both the RMAP group (P < 0.01) and the posterior PMR group (P < 0.001), but was preserved in the anterior PMR group (NS). None of the postoperative variables showed any significant difference between the early and late postoperative phases.

Conclusions

In the surgical treatment of functional MR, a PMR procedure in addition to RMAP was effective in reducing systolic MR. However, mitral valve opening assessed by MIA was restricted even after RMAP alone. The restriction was severely augmented after additional posterior PMR, but was attenuated after additional anterior PMR. The papillary muscle should be relocated in the direction of the anterior annulus to preserve the diastolic opening of the mitral valve.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-014-0185-6) contains supplementary material, which is available to authorized users.

Surgical treatment of moderate ischemic mitral regurgitation

BACKGROUND

Ischemic mitral regurgitation is associated with increased mortality and morbidity. For surgical patients with moderate regurgitation, the benefits of adding mitral-valve repair to coronary-artery bypass grafting (CABG) are uncertain.

METHODS

We randomly assigned 301 patients with moderate ischemic mitral regurgitation to CABG alone or CABG plus mitral-valve repair (combined procedure). The primary end point was the left ventricular end-systolic volume index (LVESVI), a measure of left ventricular remodeling, at 1 year. This end point was assessed with the use of a Wilcoxon rank-sum test in which deaths were categorized as the lowest LVESVI rank.

RESULTS

At 1 year, the mean LVESVI among surviving patients was 46.1±22.4 ml per square meter of body-surface area in the CABG-alone group and 49.6±31.5 ml per square meter in the combined-procedure group (mean change from baseline, -9.4 and -9.3 ml per square meter, respectively). The rate of death was 6.7% in the combined-procedure group and 7.3% in the CABG-alone group (hazard ratio with mitral-valve repair, 0.90; 95% confidence interval, 0.38 to 2.12; P=0.81). The rank-based assessment of LVESVI at 1 year (incorporating deaths) showed no significant between-group difference (z score, 0.50; P=0.61). The addition of mitral-valve repair was associated with a longer bypass time (P<0.001), a longer hospital stay after surgery (P=0.002), and more neurologic events (P=0.03). Moderate or severe mitral regurgitation was less common in the combined-procedure group than in the CABG-alone group (11.2% vs. 31.0%, P<0.001). There were no significant between-group differences in major adverse cardiac or cerebrovascular events, deaths, readmissions, functional status, or quality of life at 1 year.

CONCLUSIONS

In patients with moderate ischemic mitral regurgitation, the addition of mitral-valve repair to CABG did not result in a higher degree of left ventricular reverse remodeling. Mitral-valve repair was associated with a reduced prevalence of moderate or severe mitral regurgitation but an increased number of untoward events. Thus, at 1 year, this trial did not show a clinically meaningful advantage of adding mitral-valve repair to CABG. Longer-term follow-up may determine whether the lower prevalence of mitral regurgitation translates into a net clinical benefit. (Funded by the National Institutes of Health and the Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00806988.).

Surgical management of moderate ischemic mitral valve regurgitation: Where do we stand?

Ischemic mitral regurgitation (IMR) represents a common complication after myocardial infarction. The valve is anatomically normal and the incompetence is the result of papillary muscles displacement and annular dilatation, causing leaflets tethering. Functionally the leaflets present a restricted systolic motion due to tethering forces that displaces the coaptation surface toward the left ventricle apex. The patients present poor left ventricular function at the time of surgery and the severity of the mitral regurgitation increases the risk of mortality. Currently there is general agreement to treat surgically severe IMR nevertheless strong evidences for patient with moderate insufficiency remains poor and proper treatment debated. The most effective surgical approach for the treatment of IMR remains debated. Some authors demonstrated that coronary artery bypass graft (CABG) alone is beneficial in patients with IMR. Conversely, in most patients, moderate IMR will persist or worsen after CABG alone which translate in higher long-term mortality as a function of residual mitral regurgitation severity. A probable reason for this unclear surgical management of functional MR is due to the contemporary suboptimal results of reparative techniques. The standard surgical treatment of chronic IMR is CABG associated with undersized annuloplasty using complete ring. Though, the recurrence of mitral regurgitation remains high (> 30%) because of continous left ventricle remodeling. To get better long term results, in the last decade, several subvalvular procedures in adjunct to mitral anuloplasty have been developed. Among them, surgical papillary muscle relocation represents the most appreciated option capable to restore normal left ventricle geometry. In the next future new preoperative predictors of increased mitral regurgitation recurrence are certainly needed to find an individual time period of treatment in each patient with moderate IMR.

Incidental moderate mitral regurgitation in patients undergoing coronary artery bypass grafting: update on guidelines and key randomized trials

Incidental moderate mitral regurgitation (MR) in patients presenting for coronary artery bypass grafting (CABG) is not only common but also probably adversely affects clinical outcome. The echocardiographic evaluation of incidental MR must be comprehensive and integrated, as it remains a cornerstone in management decisions. Current guidelines support surgical mitral intervention in this setting as a reasonable option, reflecting clinical equipoise towards moderate MR in the setting of planned CABG. There are currently 2 major randomized trials in progress that will test whether surgical correction of moderate MR combined with CABG improves major clinical outcomes as compared to CABG alone. These landmark trials will be completed in the near future. In the interim, significant progress in the fields of cardiac resynchronization therapy, transcatheter mitral valve intervention, and minimally invasive mitral valve surgery promise to affect the management alternatives for moderate MR in patients undergoing CABG regardless of operative risk. It is likely that in the coming decade there will be less tolerance for incidental moderate MR given its already known outcome effects and the multimodal interventions that continue to mature with better safety profiles.