Contemporary Management of Ischemic Mitral Regurgitation: A Review

The various perioperative issues of structural heart diseases and cardiogenic shock

Up to 20 % of patients presenting with acute heart failure and cardiogenic shock have a structural etiology. Despite efforts in timely management, mortality rates remain alarmingly high, ranging from 50 % to 80 %. Surgical intervention is often the definitive treatment for structural heart disease; however, many patients are considered high risk or unsuitable candidates for such procedures. Consequently, there has been a paradigm shift towards the development of novel percutaneous management strategies and temporizing interventions. This article aims to provide a comprehensive review of the pathophysiology of valvular and structural heart conditions presenting in cardiogenic shock, focusing on the evolving landscape of mechanical circulatory support devices and other management modalities.

Prognosis for Mitral Valve Repair Surgery in Functional Mitral Regurgitation

Purpose: Our aim was to evaluate the development of new significant mitral regurgitation and long-term survival after mitral repair surgery in functional mitral regurgitation.

Methods: A retrospective observational analysis of the recurrence of functional mitral regurgitation (ischemic and nonischemic) and global mortality during follow-up of 176 patients who underwent mitral repair surgery between 1999 and 2018 in our center was conducted.

Results: The etiology of functional mitral regurgitation was ischemic in 55.7% of cases. After surgery, mitral regurgitation was 0-I in 92.3% of cases. We conducted a long-term clinical follow-up of a mean 42.2 months and an echocardiographic follow-up of a mean 41.8 months. We observed mitral regurgitation of at least grade II in 52 patients (36.9%). Survival at 1, 3, and 5 years was 78.8%, 66.7%, and 52.3%, respectively. Predictive factors for global mortality were age (hazard ratio = 1.038, p = 0.01) and a depressed preoperative ejection fraction. After a competing risk analysis, we found the only predictive factor for the recurrence of mitral regurgitation in our series to be age (sub-hazard ratio = 1.03, 95% confidence interval = 1.01–1.06, p = 0.016).

Conclusion: Repair surgery for functional mitral regurgitation shows age as the only independent predictor of recurrence. Age and depressed ejection fraction were predictors of mortality.

Mitral valve repair versus replacement in severe ischemic mitral regurgitation systematic review and meta-analysis

BACKGROUND AND AIM

Ischemic mitral regurgitation (IMR) is a serious consequence of coronary artery disease. The choice of the optimal surgical strategy remains debatable. The aim of the present meta-analysis is to compare the outcomes of mitral valve repair (RPR) versus replacement (RPL) regarding perioperative mortality, overall mortality, reoperation, recurrence of MR, and reverse remodeling after surgery.

METHODS

Electronic searches were performed using the searchable databases of Google Scholar, Pubmed, and Embase, and the search terms mitral valve, IMR, RPR, RPL, and coronary artery bypass grafting. The main outcomes of interest are perioperative mortality, overall mortality, reoperation, recurrence of MR, and reverse remodeling after surgery. Perioperative mortality was defined as death during the surgery or within 30 days after the operation.

RESULTS

There was a trend towards better perioperative survival in the RPR arm. However, the difference fell short of statistical significance [odds ratio (OR) (95% confidence interval [CI]): 0.66 (0.41-1.07), p = 0.09]. Patients submitted to RPR experienced a significantly higher MR recurrence rate when compared with their counterparts submitted to RPL [OR (95% CI): 16.8 (5.07-55.7, p = 0.00001)].

CONCLUSION

There is a trend towards lower perioperative mortality in RPR in comparison to RPL. On the other hand, RPL was associated with significantly lower recurrence rates.

Nomogram Predicts Improvement of Ischemic Mitral Regurgitation after Coronary Artery Bypass Grafting

BACKGROUND

Developing a nomogram to predict improvement in moderate ischemic mitral regurgitation (IMR) after coronary artery bypass grafting (CABG) is in need.

METHODS

Between 2010 and 2018, data were retrospectively collected from 112 patients with prior myocardial infarction and moderate IMR undergoing CABG. Patients were divided into two groups based on IMR degree 1 year after CABG as follows: Improved Group with no or mild IMR (n=54) and Failure Group with moderate or severe IMR (n=58). To determine the predictors of postoperative IMR improvement, preoperative clinical and echocardiographic data were compared, and a nomogram was formulated based on all independent predictors. Discriminative ability, calibration, and clinical usefulness of the prediction model were assessed.

RESULTS

Independent predictors of IMR improvement after CABG constructing the nomogram included duration between infarction and operation, poster-inferior to left ventricular volume ratio, maximum difference of the time to reach minimum systolic volume of 16 segments, P3 leaflet tethering angle, and annular Non-planar angle. The nomogram exhibited well-fitted calibration curves and excellent discriminative ability. The area under receiver operating characteristic curve was 0.974. Patients with a score > 236 demonstrated a high probability of IMR improvement (sensitivity, 90.7%; specificity, 93.1%). Patients in the Improved Group demonstrated greater actuarial survival rates than those in the Failure Group.

CONCLUSIONS

The nomogram combining 5 preoperative clinical and echocardiographic predictors provides an accurate preoperative estimation of moderate IMR improvement after surgery, with excellent discriminative ability. Based on this nomogram, patients with a higher score predict higher probabilities of IMR improvement.

Increased Mortality in Patients With Preoperative and Persistent Postoperative Pulmonary Hypertension Undergoing Mitral Valve Surgery for Mitral Regurgitation: A Cohort Study

Background Preoperative pulmonary hypertension (PH) is associated with excess mortality among patients with severe mitral regurgitation undergoing mitral valve surgery (MVS). However, the links between PH phenotype, pulmonary vascular remodeling, and persistent postoperative PH are not well understood. We aimed to describe the associations between components of pulmonary hemodynamics as well as postoperative residual PH with longitudinal mortality in patients with severe mitral regurgitation who received MVS. Methods and Results Patients undergoing MVS for severe mitral regurgitation from 2011 to 2016 were retrospectively identified within our health system (n=488). Mean pulmonary artery pressure and other hemodynamic variables were determined by presurgical right-heart catheterization. Postoperative pulmonary artery systolic pressure was assessed on echocardiogram 42 to 365 days post-MVS. Longitudinal survival over a mean 3.9 years of follow-up was evaluated using Cox proportional hazards modeling to compare survival after adjustment for demographics, surgical characteristics, and comorbidities. Pre-MVS prevalence of PH was high at 85%. After adjustment, each 10-mm Hg increase in preoperative mean pulmonary artery pressure was associated with a 1.38-fold increase in risk of death (95% CI, 1.13-1.68). Elevated preoperative pulmonary vascular resistance, transpulmonary gradient, and right atrial pressure were similarly associated with increased mortality. Among 231 patients with postoperative echocardiogram, evidence of PH on echocardiogram (pulmonary artery systolic pressure ≥35 mm Hg) was associated with increased risk of death (hazard ratio [HR], 2.02 [95% CI, 1.17-3.47]); however, this was no longer statistically significant after adjustment (HR, 1.55 [95% CI, 0.85-2.85]). Conclusions In patients undergoing MVS for mitral regurgitation, preoperative PH, and postoperative PH were associated with increased mortality.

Structural Heart Disease Emergencies

Structural heart disease (SHD) emergencies include acute deterioration of a stable lesion or development of a new critical lesion. Structural heart disease emergencies can produce heart failure and cardiogenic shock despite preserved systolic function that may not respond to standard medical therapy and typically necessitate surgical or percutaneous intervention. Comprehensive Doppler echocardiography is the initial diagnostic modality of choice to determine the cause and severity of the underlying SHD lesion. Patients with chronic SHD lesions which deteriorate due to intercurrent illness (eg, infection or arrhythmia) may not require urgent intervention, whereas patients with an acute SHD lesion often require definitive therapy. Medical stabilization prior to definitive intervention differs substantially between stenotic lesions (aortic stenosis, mitral stenosis, left ventricular outflow tract obstruction) and regurgitant lesions (aortic regurgitation, mitral regurgitation, ventricular septal defect). Patients with regurgitant lesions typically require aggressive afterload reduction and inotropic support, whereas patients with stenotic lesions may paradoxically require β-blockade and vasoconstrictors. Emergent cardiac surgery for patients with decompensated heart failure or cardiogenic shock carries a substantial mortality risk but may be necessary for patients who are not eligible for catheter-based percutaneous SHD intervention. This review explores initial medical stabilization and subsequent definitive therapy for patients with SHD emergencies.

Patients over 70 years of age with moderate ischemic mitral regurgitation undergoing surgical revascularization plus mitral valve repair: insights from a single-center study of propensity-matched data

Background

Elderly patients, compared with the young, have a higher burden of surgical risk factors with reduced functional capacity and increased comorbidities conditions, and may have worse clinical outcomes. So far, few reports have focused on clinical outcomes of patients over 70 years of age with moderate chronic ischemic mitral regurgitation (IMR) undergoing mitral valve repair at the time of coronary artery bypass grafting (CABG). This single-center study of propensity-matched data attempts to answer a question: compared with patients with age of 70 or less, whether patients over 70 years of age with moderate IMR undergoing CABG plus mitral valve repair receive poor outcomes.

Methods

All eligible patients were included in this study and were entered into either an elderly group (n=142) or a control group (n=182) according to patients' age. In-hospital outcomes (consisting of surgical mortality and major postoperative morbidity) and midterm clinical outcomes (including all-cause mortality and recurrent mitral regurgitation) were compared after propensity score matching (1:1).

Results

Using propensity-score matching, 103 pairs of patients were successfully established in a 1:1 ratio. No significant differences between the two matched groups were found with regard to surgical mortality (5.8% vs. 3.9%, P=0.754) and major postoperative morbidity. A total of 184 patients (91 in the elderly group and 93 in the control group) received regular follow-up visit with the median duration of 38 months [interquartile range (IQR), 27-56 months]. There were not any significant differences between the two matched groups regarding overall survival and recurrent IMR-free survival (stratified log-rank P=0.185 and stratified log-rank P=0.453, respectively). The elderly group as compared to the control group did not affect midterm mortality via cox proportional hazard regression (propensity score adjusted hazard ratio, 1.143; 95% confidence interval, 0.761-1.943; P=0.285).

Conclusions

Patients over 70 years of age with moderate chronic IMR undergoing combined CABG and mitral valve repair may receive favorable in-hospital and midterm clinical outcomes.

Elderly Patients with Moderate Chronic Ischemic Mitral Regurgitation: Coronary Artery Bypass Grafting Alone or Concomitant Mitral Annuloplasty?

Background

An increasing number of elderly patients with ischemic mitral regurgitation (IMR) are referred for coronary artery bypass grafting (CABG). However, data about the management of elderly patients with moderate IMR are scanty. This study evaluates the impacts of two surgical approaches (CABG alone or concomitant mitral annuloplasty (MAP)) on in-hospital and midterm outcomes, to attempt to determine an appropriate treatment option for elderly patients with moderate chronic IMR.

Methods

All eligible patients over 65 years of age were included and were entered into either a MAP group (patients undergoing CABG plus MAP, n = 96) or a CABG group (patients receiving CABG alone, n = 104). Baseline and surgical characteristics were analyzed, and in-hospital and midterm outcomes between groups were compared after propensity score-matching (1 : 1).

Results

Using propensity score-matching, 82 pairs of patients were successfully established in a 1 : 1 ratio. No significant differences between the two matched groups were found regarding surgical mortality (4.9% vs. 1.2%, p=0.173) and major postoperative morbidity. 150 patients (76 in the MAP group and 74 in the CABG group) received regular follow-up visit with the median duration of 37 months. Compared with the CABG group, the MAP group received a similar overall survival but a better recurrent MR-free survival (stratified log-rank p, 0.492 and < 0.001, respectively). Using Cox regression, the MAP group as compared with the CABG group did not affect midterm survival probability (propensity score-adjusted hazard ratio, 0.854; 95% confidence interval, 0.571–2.729, p=0.630). Additionally, patients in the MAP group had a significantly lower ratio of NYHA class III-IV at the latest follow-up by comparison with patients in the CABG group (19.7% vs. 35.5%, p=0.033).

Conclusion

Compared with CABG alone, concomitant mitral annuloplasty is associated with improved midterm outcomes (including reduced IMR recurrence and improved cardiac functional class) but shares similar surgical mortality and major postoperative morbidity and may be a promising treatment option for elderly patients with moderate chronic IMR.

Moderate Chronic Ischemic Mitral Regurgitation

The benefits of concomitant mitral valve procedure (MVP) for treating moderate chronic ischemic mitral regurgitation (IMR) during coronary artery bypass grafting (CABG) have not been clearly established. This study aimed to determine the incidence of moderate or more residual mitral regurgitation (MR) following CABG plus MVP for moderate chronic IMR, and to evaluate the impacts of concomitant MVP vs. CABG alone on clinical outcomes based on propensity-matched data.All eligible patients were entered into either the MVP group (CABG plus MVP, n = 184) or CABG group (CABG alone, n = 162). Moderate or more residual MR rate was investigated, and in-hospital and follow-up outcomes between the groups were compared after matching.Moderate or more residual MR rate was 11.4% at 1 year and 22.9% at 2 years after CABG plus MVP, respectively. Patients in the MVP group as compared with the CABG group had significantly lower moderate or more residual MR rates at various postoperative time points (all P < 0.001). Grouping was not an independent risk factor for in-hospital adverse events in multivariate logistic regression analysis. Also, grouping was a significant variable related to moderate or more residual MR rate and NYHA class III-IV at the latest follow-up in Cox regression analysis (HR = 0.391, 95% CI 0.114-0.628; HR = 0.419, 95% CI 0.233-0.819, respectively).Concomitant MVP as compared with CABG alone for treating moderate chronic IMR was associated with a reduction in moderate or more residual MR rate and an improvement in NYHA functional status, with no increase in in-hospital adverse events or follow-up death.