Predictors of Mortality in Patients With Severe Ischemic Cardiomyopathy Undergoing Surgical Mitral Valve Intervention

Off-Pump Revascularization in Moderate Ischemic Mitral Regurgitation

BACKGROUND

 Ischemic mitral regurgitation (IMR) is associated with high mortality and poor outcomes. The surgical management of moderate IMR is still an object of debate.

METHODS

 Patients with moderate IMR who underwent isolated off-pump coronary bypass grafting (OPCAB) with facile stabilization between January 2015 and February 2022 were analyzed. The primary endpoint was the remaining IMR and echocardiographic findings while the secondary outcomes were defined as mortality, major adverse events, and postoperative functional status.

RESULTS

 Of 541 patients who underwent isolated OPCAB in this period, there were 62 patients with concomitant moderate IMR. The mean follow-up period was 19.4 ± 21.6 months. The median number of the coronary anastomosis was 4. In 58.06% (n = 36), the regurgitation regressed. Left atrial (LA) diameter significantly decreased postoperatively (p = 0.040). Increased LA diameter was associated with increased major adverse events (p = 0.010). Rehospitalization rates were higher in low ejection fraction (EF). The postoperative poor functional status (New York Heart Association [NYHA] III-IV) was correlated with an increased postoperative left ventricular end-systolic diameter (LVESD; 41.75 ± 6.13 vs. 34.79 ± 6.8 mm, p = 0.05). Mortality (4.8%, n = 3) was associated with older age and increased preoperative systolic pulmonary artery pressure (PAP; p = 0.050 and p = 0.046, respectively).

CONCLUSION

 LA diameter, LVESD, mean systolic PAP, left ventricular ejection fraction (LVEF), and age are important predictors for outcomes in IMR. Remaining IMR per se is not directly correlated with increased mortality and major adverse cardiac and cerebrovascular events. The facile stabilization technique we used appears to be advantageous due to the feasibility of full revascularization of all intended vessels, particularly of the inferoposterior wall by providing excellent vision without compression of the heart.

Are there etiology-specific risk factors for adverse outcomes in patients on Impella 5.5 support?

Objectives

To identify possible etiology-specific differences in preoperative risk factors for major adverse events during Impella 5.5 support in patients with ischemic (ICM) and nonischemic cardiomyopathy (NICM).

Methods

From October 2019 to January 2023, 228 Impella 5.5 devices were inserted at our institution. Patients were stratified into ICM (n = 124) and NICM (n = 104) cohorts. The primary outcome was a composite of death/stroke/new-onset dialysis while actively receiving Impella 5.5 support. Random forests identified preoperative factors predictive of the primary outcome separately for each cohort, with ranking by variable importance.

Results

The primary outcome occurred in 42 (34%) patients with ICM and 35 (34%) patients with NICM. Twenty-one (17%) patients with ICM and 21 (20%) patients with NICM died on Impella 5.5; stroke occurred in 12 (9.7%) patients with ICM and 3 (2.9%) patients with NICM, and new-onset dialysis was initiated in 23 (19%) patients with ICM and 24 (23%) patients with NICM while actively receiving Impella 5.5 support. Risk factors reflecting systemic and myocardial cellular injury, end-organ and cardiopulmonary failure, right ventricular dysfunction, and smaller left ventricular dimensions were most predictive of adverse outcomes in both cohorts. Indications for Impella 5.5 and device strategy (bridge to recovery, advanced therapies, or decision) were not top risk factors in either cohort.

Conclusions

Risk factors related to preoperative stability, right ventricular dysfunction, and left ventricular size were more predictive of adverse outcomes while actively receiving Impella 5.5 support than indication or device strategy. These factors could help identify high-risk patients who may benefit from additional tailored management to reduce their risk for these impactful adverse outcomes while on Impella 5.5 support.

Impact of complete revascularization in coronary artery bypass grafting for ischemic cardiomyopathy

Objective

In patients with ischemic cardiomyopathy, coronary artery bypass grafting ensures better survival than medical therapy. However, the long-term clinical impact of complete revascularization remains unclear. This observational study aimed to evaluate the effects of complete revascularization on long-term survival and left ventricular functional recovery in patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting.

Methods

We retrospectively reviewed outcomes of 498 patients with ischemic cardiomyopathy who underwent complete (n = 386) or incomplete (n = 112) myocardial revascularization between 1993 and 2015. The baseline characteristics were adjusted using inverse probability of treatment weighting to reduce the impact of treatment bias and potential confounding. The mean follow-up duration was 77.2 ± 42.8 months in survivors.

Results

The overall 5-year survival rate (complete revascularization, 72.5% vs incomplete revascularization, 57.9%, P = .03) and freedom from all-cause death and/or readmission due to heart failure (54.5% vs 40.1%, P = .007) were significantly greater in patients with complete revascularization than those with incomplete revascularization. After adjustments using inverse probability of treatment weighting, the complete revascularization group demonstrated a lower risk of all-cause death (hazard ratio, 0.61; 95% confidence interval, 0.43-0.86; P = .005) and composite adverse events (hazard ratio, 0.59; 95% confidence interval, 0.44-0.79; P < .001) and a greater improvement in the left ventricular ejection fraction 1-year postoperatively (absolute change: 11.0 ± 11.9% vs 8.3 ± 11.4%, interaction effect P = .05) than the incomplete revascularization group.

Conclusions

In patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting, complete revascularization was associated with better long-term outcomes and greater left ventricular functional recovery and should be encouraged whenever possible.

Effect of early versus late onset mitral regurgitation on left ventricular remodeling in ischemic cardiomyopathy in an animal model

BACKGROUND

Patients who survive a myocardial infarction have progressive cardiac dysfunction and ventricular remodeling. Mitral regurgitation is often diagnosed in these patients, and is a risk factor that portends poor prognosis. Whether such postinfarction mitral regurgitation magnifies adverse left ventricular remodeling is unclear, which was studied in an animal model.

METHODS

Forty-one adult rats were induced with myocardial infarction using left coronary artery ligation and assigned to 3 groups: group 1, myocardial infarction only; group 2, myocardial infarction with severe mitral regurgitation introduced after 4 weeks; and group 3, myocardial infarction with severe mitral regurgitation introduced after 10 weeks. Valve regurgitation was introduced by advancing a transapical ultrasound-guided needle into the mitral valve anterior leaflet. Animals were survived to 20 weeks from the index procedure, with biweekly cardiac ultrasound, and invasive hemodynamics and histology at termination.

RESULTS

At 20 weeks, end diastolic volume was largest in the groups with mitral regurgitation, compared with the group without the valve lesion (group 1, 760.9 ± 124.6 μL; group 2, 958.0 ± 115.1 μL; group 3, 968.3 ± 214.9 μL). Similarly, end systolic volume was larger in groups with regurgitation (group 1, 431.2 ± 152.6 μL; group 2, 533.2 ± 130.8 μL; group 3, 533.1 ± 177.5 μL). In the infarction-only group, left ventricular remodeling was maximal until 6 weeks and plateaued thereafter. In groups with mitral regurgitation, left ventricular remodeling was significantly elevated at the onset of regurgitation and persisted.

CONCLUSIONS

Mitral regurgitation is a potent driver of adverse cardiac remodeling after a myocardial infarction, irrespective of the timing of its onset.

Effect of left ventricular hyperenhancement in magnetic resonance imaging on reverse remodeling after mitral valve repair for moderate ischemic mitral regurgitation

We aimed to investigate cardiac magnetic resonance imaging (MRI)-derived predictors of a lack of left ventricular (LV) reverse remodeling after undersized mitral annuloplasty (uMAP) for moderate ischemic mitral regurgitation (IMR). We retrospectively reviewed 31 patients who underwent uMAP for moderate IMR and cardiac MRI evaluation between 2004 and 2017. Cardiac MRI evaluation included cine MRI LV and right ventricular volumetric measurements and gadolinium-enhanced MRI assessment of myocardial scarring. LV dimensions were assessed preoperatively, postoperatively, and at follow-up using serial transthoracic echocardiography, and the mid-term (median, 49 months) predictors of a lack of LV reverse remodeling were analyzed. At the mid-term follow-up (mean follow-up period: 85 ± 40 months), 15 patients exhibited reverse LV remodeling. The relative reduction in LV dimension at follow-up was negatively correlated with the preoperative number of LV segments with myocardial infarction (MI) (defined as an LV segment with >25% enhancement). The optimal cut-off for predicting a lack of reverse LV remodeling at follow-up was >5 LV segments with MI, with a sensitivity and specificity of 92% and 92%, respectively. This cut-off value also predicted all-cause mortality at follow-up, with a sensitivity and specificity of 88% and 67%, respectively. The presence of >5 LV segments with MI on gadolinium-enhanced MRI might be a useful predictor of lack of reverse LV remodeling and all-cause mortality outcomes after undersized mitral annuloplasty for moderate IMR.

The association between myocardial scar and the response of moderate ischemic mitral regurgitation to isolated coronary artery bypass grafting

Background

The factors that associated with the response of moderate ischemic mitral regurgitation (IMR) to isolated coronary artery bypass grafting (CABG) remain unclear. This study aims to evaluate whether left ventricular (LV) myocardial scar assessed by cardiovascular magnetic resonance (CMR) is associated with the outcome of moderate IMR after isolated CABG.

Methods

Forty-six patients with coronary artery disease (CAD) and moderate IMR who underwent isolated CABG between January 2014 and February 2019 in Anzhen Hospital Affiliated to Capital Medical University were enrolled in this case-control study. All patients underwent CMR and echocardiography before surgery. Patients were classified into two groups according to the severity of IMR 1 year after CABG: an improved group (no or mild IMR) and an unimproved group (moderate or severe IMR). Univariate and multivariate logistic regression analyses were used to assess the association between individual variables and unimproved IMR at 1-year post-CABG.

Results

Compared to patients in the improved group, the patients in the unimproved group had a significantly greater amount of LV myocardial scar (18.0%±9.5% vs. 30.8%±11.2%, P<0.001). In the multiple logistic regression model, after adjustment for age, sex, and body mass index, only LV myocardial scar (OR: 0.89, 95% CI: 0.83–0.96, P=0.001) was independently associated with unimproved IMR after isolated CABG. Furthermore, there was no difference in the 3-year overall survival rates between the two groups (92.3% vs. 90.3%, P=0.46). In addition, patients in the unimproved group had a higher New York Heart Association (NYHA) classification (P=0.01) and more major adverse cardiac events such as MI, angina pectoris, and readmission for heart failure (P=0.03).

Conclusions

A greater amount of preoperative LV myocardial scar was associated with unimproved moderate IMR after isolated CABG. Measuring preoperative LV myocardial scar is helpful to predict post-operative outcome and determine optimal surgery in patients with moderate IMR.

Guide to functional mitral regurgitation: a contemporary review

Functional mitral regurgitation (FMR) occurs in the absence of organic mitral valve (MV) disease and is a result of LV dysfunction due to ischemic vs. non ischemic etiologies. The prevalence of FMR is increasing, as 2.0-2.5 million people in the USA were diagnosed with FMR in 2000-and this number is expected to double to 4 million by 2030. FMR tends to develop in a significant number of patients after myocardial infarction (MI) and many develop heart failure (HF) subsequently with mortality rates ranging from 15-40% at 1 year. Therefore, there has been much interest and effort to develop optimized methods for quantifying and classifying the severity of FMR, as well as developing effective therapeutic interventions to improve outcomes in patients with significant FMR. Echocardiogram is typically the primary diagnostic method of assessment, however, there have been various technological advances including cardiac CT and cardiac MRI that can better guide quantification and management of this disease. Management of this disease is mostly aimed at optimizing left ventricular (LV) remodeling with surgical and transcatheter management gaining more popularity with recent times. The purpose of this paper is to provide a comprehensive review of the current evaluation methods and interventional strategies for FMR.

Surgical repair of ischemic mitral regurgitation: one ring does not fit all

PURPOSE OF REVIEW

The review summarizes the key parameters that can aid in determining the optimal treatment of ischemic mitral regurgitation (IMR).

RECENT FINDINGS

Left ventricular (LV) and mitral valve (MV) parameters are important for surgical planning and risk stratification in IMR. Although LV dimensions is one of the main parameters used in the guidelines, volumes more accurately depict LV remodelling. Furthermore, wall motion abnormalities and wall motion score index can also be useful for surgical planning in treatment of IMR. Viability is best measured with cardiac magnetic resonance, but it is not feasible in certain centres. In contrast, measurement of strain with echocardiography is an emerging and feasible tool for estimating viability. MV leaflet tethering and pattern measured with echocardiography are also useful for MV surgery. Anterior leaflet excursion angle can identify patients in whom undersized ring annuloplasty is potentially unsuitable.

SUMMARY

Treatment of IMR relies on accurate parameters that can determine the optimal surgical approach. In some patients, lack of viable myocardium suggests inadequacy of revascularization and thus, an adjunctive left ventricular reconstruction may be necessary. Degree and pattern of MV leaflet tethering can indicate whether ring annuloplasty, which is the most common repair technique, is sufficient or an adjunctive sub-valvular intervention is beneficial.

Multimodality Imaging in Secondary Mitral Regurgitation

Secondary mitral regurgitation (sMR) is characterized by left ventricular (LV) dilatation or dysfunction, resulting in failure of mitral leaflet coaptation. sMR complicates up to 35% of ischaemic cardiomyopathies (1) and 57% of dilated cardiomyopathies (2). Due to the prevalence of coronary artery disease worldwide, ischaemic cardiomyopathy is the most frequently encountered cause of sMR in clinical practice. Although mortality from cardiovascular disease has gradually fallen in Western countries, severe sMR remains an independent predictor of mortality (3) and hospitalization for heart failure (4). The presence of even mild sMR following acute MI reduces long-term survival free of major adverse events (1). Such adverse outcomes worsen as the severity of sMR increases, due to a cycle in which LV remodeling begets sMR and vice versa. Current guidelines do not recommend invasive treatment of the sMR alone as a first-line approach, due to the paucity of evidence supporting improvement in clinical outcomes. Furthermore, a lack of international consensus on the thresholds that define severe sMR has resulted in confusion amongst clinicians determining whether intervention is warranted (5, 6). The recent Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT) trial (7) assessing the effectiveness of transcatheter mitral valve repair is the first study to demonstrate mortality benefit from correction of sMR and has reignited interest in identifying patients who would benefit from mitral valve intervention. Multimodality imaging, including echocardiography and cardiovascular magnetic resonance (CMR), plays a key role in helping to diagnose, quantify, monitor, and risk stratify patients for surgical and transcatheter mitral valve interventions.

Advances in MRI Applications to Diagnose and Manage Cardiomyopathies

PURPOSE OF REVIEW

The prevalence of heart failure continues to rise, and imaging characterization of the cardiomyopathic process is important for identifying myocardial disease, initiating appropriate treatment, and improving outcomes. We aimed to summarize recent advances in cardiac magnetic resonance imaging (CMR) applications for the diagnosis, characterization, and implications on management of various cardiomyopathies.

RECENT FINDINGS

Parametric mapping by CMR has emerged as an important advancement in quantification of myocardial fibrosis, increased extracellular space, and myocardial edema. In addition, improved assessment of myocardial function with myocardial strain assessment may provide early identification of patients at risk and determining responsiveness to therapeutic interventions. Novel MRI techniques and the advent of artificial intelligence may help to uncover important mechanistic insights into the cardiomyopathic process. Innovative CMR techniques continue to evolve, and it will be of interest to determine how these advances can be incorporated into clinical practice to improve diagnosis, treatment, and management of patients with cardiomyopathies.

Heart valve operations associated with reduced risk of death from mitral valve disease but other operations associated with increased risk of death: a national population-based case-control study

Background

Mitral valve disease is the most common heart valve disease worldwide. Heart valve operation is the predominant treatment strategy for heart valve disease. This study analyzed the death risk from heart valve disease with respect to the frequency of heart valve operation and other operations in patients with mitral valve disease.

Materials and methods

We conducted a retrospective nationwide population-based case–control study using a claims dataset from Taiwan’s National Health Insurance Research Database. The case and control groups enrolled mitral valve disease patients from 2002 to 2013 who had either underwent an heart valve operation procedure or not, respectively. Conditional logistic regression was estimated the odds ratios (ORs) associated with various risk factors for heart valve operation-related death, including other operations and comorbidities.

Results

A total of 25,964 patients with mitral valve disease were recruited for the study and divided into heart valve operation (600 patients) and non-heart valve operation (25,364 patients) groups. After matching, a total of 1800 non-heart valve operation patients were selected for final analysis. Heart valve operation was associated with decreased risk of death (adjusted OR [aOR] 0.439), but operations related to other cardiovascular disease (CVD, aOR 3.691), respiratory conditions (aOR 3.210), and the urinary system (aOR 1.925) were associated with increased risk of death for patients with mitral valve disease. Patients with mitral valve disease and diabetes (aOR 1.505), chronic kidney disease (CKD, aOR 3.760), or emphysema (aOR 2.623) also had a higher risk of death. Patients who underwent more heart valve operations had a lower risk of death from mitral valve disease, but patients who underwent more other operations had a higher risk of death from mitral valve disease.

Conclusions

The death risk for patients with mitral valve disease patients could be lowered by more frequently performing heart valve operations. However, the risk of death is increased for patients with mitral valve disease who more frequently undergo other operations, chiefly those for other CVD system, respiratory conditions, and urinary system, or have comorbidities such as diabetes, chronic kidney disease, and emphysema.

Predictive impact of previous coronary artery bypass grafting on mortality after MitraClip implantation for ischemic functional mitral regurgitation

BACKGROUND

Many candidates with ischaemic functional mitral regurgitation (FMR) have previously undergone coronary artery bypass grafting (CABG), in which transcatheter mitral valve repair can be reasonable for ameliorating the deteriorated hemodynamic and heart failure symptoms. We sought to elucidate the outcomes of MitraClip (MC) implantation in patients with symptomatic ischaemic FMR after CABG.

METHODS

We investigated clinical characteristics, outcomes and predictive impact of previous CABG on mortality in ischaemic FMR patients who underwent MC implantation from two high-volume centres in Germany.

RESULTS

We enrolled 159 patients who previously underwent CABG. Compared with a reference group that did not previously undergo CABG (n = 182), the cohort consisted of more elderly patients (75.0, standard deviation [SD] 7.7 versus 72.9, SD 9.6 years, p = 0.028), more men (84% vs. 69%, p < 0.001), and reduced tricuspid annular plane systolic excursion (14.0, SD 4.0, vs. 16.6, SD 4.6 mm, p < 0.0001). The CABG group showed similar outcomes regarding procedural success (91% vs. 94%, p = 0.24) and 30-day mortality (5.0% vs. 6.0%, p = 0.68), but worse survival after MC implantation (log-rank p = 0.019, hazard ratio 1.56 [95% confidence interval (CI) 1.08-2.26]). After propensity score matching (n = 224), the hazard ratio was 1.18 [95%CI 0.76-1.84] without statistical significance (p = 0.46).

CONCLUSIONS

Transcatheter mitral valve repair using the MC is a viable treatment option for patients with symptomatic ischaemic FMR after CABG. Although the baseline characteristics seemed to point to sick patients, CABG itself had only a modest impact on survival.

Surgical intervention for ischemic mitral regurgitation: how can we achieve better outcomes?

Ischemic mitral regurgitation (MR) is a common complication of myocardial infarction. Left ventricular (LV) dysfunction and distortion of the subvalvular apparatus are the main contributors to ischemic MR. Coronary artery bypass grafting alone, mitral valve replacement, and mitral valve repair, with or without subvalvular procedures, have been performed for moderate-to-severe ischemic MR. Several randomized studies on the surgical treatment of ischemic MR have been performed; however, the optimal surgical strategy remains controversial because none have demonstrated a clear survival benefit. Since the mechanisms of ischemic MR are complex and multifactorial, comprehensive preoperative assessment of LV function and geometry (both global and regional), mitral valve configuration, viability testing, and exercise echocardiography are needed. A better understanding of this complicated disease and of the advantages and limitations of each procedure may help us devise more effective patient-specific surgical treatment strategies and achieve better outcomes.