2015 The American Association for Thoracic Surgery Consensus Guidelines: Ischemic mitral valve regurgitation

Surgical strategy and outcomes for atrial functional mitral regurgitation: All functional mitral regurgitation is not the same!

OBJECTIVE

Functional mitral regurgitation (FMR) is a cardiac pathology that causes the mitral valve to malfunction, leading to mitral regurgitation (MR). The optimal strategy for FMR remains unclear, and FMR outcomes are poor. All etiologies of FMR might not be the same, and subdividing patients with FMR caused by atrial (AFMR) versus ventricular FMR pathology might be important. Herein, we present outcomes of patients with AFMR to define this "new" population.

METHODS

Data of patients who underwent mitral valve repair for MR from 2000 to 2020 were reviewed. Patients with degenerative/myxomatous disease, ejection fraction <50% (ventricular FMR), and miscellaneous etiologies including endocarditis and rheumatic disease were excluded to isolate a population of "pure" AFMR patients. Descriptive characteristics and outcomes data were analyzed.

RESULTS

Among 123 total AFMR patients, mean preoperative left atrial dimensions were enlarged to 4.9 (95% CI, 4.7-5.0) cm, whereas mean preoperative left ventricular diastolic dimensions remained near normal at 5.0 (95% CI, 4.9-5.2) cm. Preoperative atrial fibrillation was noted in 61% (74/123). Echocardiogram was performed in 58% (71/123) of patients at a median of 569 (interquartile range, 75-1782) days after surgery. Of those, 72% (51/71) had trivial or no MR, 22% (16/71) mild, and only 6% (4/71) moderate or greater MR. Only 1.6% (2/123) required redo mitral valve reoperation. Estimated 5-year survival was 74%.

CONCLUSIONS

Patients with AFMR do well after mitral valve repair using an annuloplasty ring, with low rates of reoperation, mortality, and recurrence of MR. Mitral annuloplasty should be considered the surgical therapy of choice for AFMR.

Prosthetic choice in mitral valve replacement for severe chronic ischemic mitral regurgitation: Long-term follow-up

BACKGROUND

Prosthetic choice for mitral valve replacement is generally driven by patient age and patient and surgeon preference, and current guidelines do not discriminate between different etiologies of mitral valve disease. Our objective was to assess and compare short- and long-term outcomes after mitral valve replacement among patients with biological or mechanical prostheses in the setting of severe ischemic mitral regurgitation.

METHODS

Between 2000 and 2016, 424 patients underwent mitral valve replacement for severe ischemic mitral regurgitation at our institution, using biological prosthesis in 188 (44%) and mechanical prosthesis in 236 (56%). A 1:1 propensity score match (n = 126 per group) and inverse probability of treatment weighting were used to compare groups. Short-term outcomes included in-hospital mortality and other cardiovascular adverse events. Long-term outcomes included survival and hospital readmission for cardiovascular causes, stroke, and major bleeding.

RESULTS

In-hospital mortality and early postoperative adverse events were similar between groups in the propensity score match and inverse probability of treatment weighting cohorts. Overall long-term survival was similar at 5 and 9 years, but mechanical prosthesis recipients were more frequently readmitted to hospital for cardiovascular causes, including stroke and non-neurological bleeding in propensity score matching and inverse probability of treatment weighting analyses (all P values < .004). Type of prosthesis did not independently influence all-cause mortality (hazard ratio, 1.01; 95% confidence interval, 0.71-1.43; P = .959), but placement of a mechanical prosthesis was associated with increased risk of readmission for cardiovascular events (hazard ratio, 1.65; 95% confidence interval, 1.17-2.32; P = .004) among matched patients.

CONCLUSIONS

The type of prosthesis has no influence on long-term survival among patients with severe ischemic mitral regurgitation undergoing mitral valve replacement. There may be an increased risk of neurologic events and serious bleeding associated with mechanical prostheses.

Results of different therapeutic strategies for left ventricular aneurysm with mitral regurgitation

OBJECTIVE

This study aims to compare the midterm outcomes of left ventricular reconstruction (LVR) added to coronary artery bypass grafting (CABG) with those of CABG alone in patients with left ventricular aneurysm (LVA) and mild or moderate mitral regurgitation (MR). We also assessed the impact of LVR on the degree of MR.

METHODS

A total of 130 patients (77 who underwent CABG plus LVR and 53 who underwent CABG alone) with concomitant mild or moderate MR were included in the study population. All-cause mortality was considered the primary endpoint. Major adverse cardiovascular and cerebrovascular events (MACCEs), including death, myocardial infarction, stroke, and subsequent mitral valve surgery, were considered secondary endpoints. Kaplan-Meier analysis was performed to evaluate event-free survival. MR was graded 0 to 4+ by echocardiogram.

RESULTS

The median follow-up time among all patients was 22 months. There was a significant difference between the CABG plus LVR and CABG alone groups with regard to all-cause mortality ( P = 0.019). However, the statistical difference was not observed in cardiogenic mortality ( P = 0.186) and MACCEs ( P = 0.107). In the grade of MR, the two groups both resulted in the decreased grade of MR, but the CABG plus LVR group had a significant number of patients improving to 0 or 1+ ( P = 0.030).

CONCLUSION

The clinical outcomes of CABG alone are comparable with those of CABG plus LVR in patients with LVA and mild or moderate MR. However, CABG+LVR demonstrated greater reduction in MR severity after surgery than CABG alone.

Ex Vivo Model of Ischemic Mitral Regurgitation and Analysis of Adjunctive Papillary Muscle Repair

Ischemic mitral regurgitation (IMR) is particularly challenging to repair with lasting durability due to the complex valvular and subvalvular pathologies resulting from left ventricular dysfunction. Ex vivo simulation is uniquely suited to quantitatively analyze the repair biomechanics, but advancements are needed to model the nuanced IMR disease state. Here we present a novel IMR model featuring a dilation device with precise dilatation control that preserves annular elasticity to enable accurate ex vivo analysis of surgical repair. Coupled with augmented papillary muscle head positioning, the enhanced heart simulator system successfully modeled IMR pre- and post-surgical intervention and enabled the analysis of adjunctive subvalvular papillary muscle repair to alleviate regurgitation recurrence. The model resulted in an increase in regurgitant fraction: 11.6 ± 1.7% to 36.1 ± 4.4% (p < 0.001). Adjunctive papillary muscle head fusion was analyzed relative to a simple restrictive ring annuloplasty repair and, while both repairs successfully eliminated regurgitation initially, the addition of the adjunctive subvalvular repair reduced regurgitation recurrence: 30.4 ± 5.7% vs. 12.5 ± 2.6% (p = 0.002). Ultimately, this system demonstrates the success of adjunctive papillary muscle head fusion in repairing IMR as well as provides a platform to optimize surgical techniques for increased repair durability.

Clinical Outcomes of Patients with Coronary Artery Diseases and Moderate Left Ventricular Dysfunction: Percutaneous Coronary Intervention versus Coronary Artery Bypass Graft Surgery

Purpose

Percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) are two revascularization strategies for patients with coronary artery disease (CAD) and left ventricular dysfunction. However, the comparisons of effectiveness between the two strategies are insufficient. This study is aimed to compare the effectiveness between PCI and CABG among patients with moderate left ventricular dysfunction.

Patients and Methods

A total of 1487 CAD patients with moderate reduced ejection fraction (36%≤EF≤40%), who underwent either PCI or CABG, were enrolled in a real-world cohort study (No. ChiCTR2100044378). Clinical outcomes included short- and long-term all-cause mortality, rates of heart failure (HF) hospitalization and repeat revascularization. Propensity score matching was used to balance the two cohorts.

Results

PCI was associated with lower 30-day mortality rate (hazard ratio [HR] [95% CI], 0.35 [0.15–0.83]; P=0.02). At a mean follow-up of 4.5 years, PCI and CABG had similar all-cause death (HR [95% CI], 0.82 [0.56–1.20]; P=0.30) and heart failure (HF) hospitalization (HR [95% CI], 0.93 [0.54–1.60]; P=0.79), but PCI had higher risk of repeat revascularization (HR [95% CI], 8.62 [3.67–20.23]; P<0.001). Improvement in EF measured at 3 months later after revascularization was also similar between PCI and CABG (P for interaction=0.87).

Conclusion

CAD patients with moderate reduced EF who had PCI had lower short-term mortality rate but higher risk of repeat revascularization during follow-up than patients who had CABG. PCI showed comparable long-term survival, HF hospitalization risk, and EF improvement.

Joint preoperative transthoracic and intraoperative transoesophageal echocardiographic assessment of functional mitral regurgitation severity provides better association with long-term mortality

OBJECTIVES

Functional mitral regurgitation (MR) is observed with ischaemic heart disease or aortic valve disease. Assessing the value of mitral valve repair or replacement (MVR/P) is complicated by frequent discordance between preoperative transthoracic echocardiographic (pTTE) and intraoperative transoesophageal echocardiographic (iTOE) assessment of MR severity. We examined the association of pTTE and iTOE with postoperative mortality in patients with or without MR, at the time of coronary artery bypass grafting (CABG) and/or aortic valve replacement without MVR/P.

METHODS

Medical records of 6629 patients undergoing CABG and/or aortic valve replacement surgery with or without functional MR and who did not undergo MVR/P were reviewed. MR severity assessed by pTTE and iTOE were examined for association with postoperative mortality using proportional hazards regression while accounting for patient and operative characteristics.

RESULTS

In 72% of 709 patients with clinically significant (moderate or greater) functional MR detected by pTTE, iTOE performed after induction of anaesthesia demonstrated a reduction in MR severity, while 2% of patients had increased severity of MR by iTOE. iTOE assessment of MR was better associated with long-term postoperative mortality than pTTE in patients with moderate MR [hazard ratio (HR) 1.31 (1.11-1.55) vs 1.02 (0.89-1.17), P-value for comparison of HR 0.025] but was not different for more than moderate MR [1.43 (0.96-2.14) vs 1.27 (0.80-2.02)].

CONCLUSIONS

In patients undergoing CABG and/or aortic valve replacement without MVR/P, these findings support intraoperative reassessment of MR severity by iTOE as an adjunct to pTTE in the prediction of mortality. Alone, these findings do not yet provide evidence for an operative strategy.

Results of Left Ventricular Reconstruction With and Without Mitral Valve Surgery

BACKGROUND

This study aims to compare the midterm outcomes of left ventricular reconstruction with those of left ventricular reconstruction plus mitral valve surgery in patients with left ventricular aneurysm due to anterior myocardial infarction and moderate mitral regurgitation.

METHODS

A total of 523 patients (75 who underwent left ventricular reconstruction plus mitral valve surgery and 448 who underwent left ventricular reconstruction) with concomitant moderate mitral regurgitation were included in the study population. All-cause mortality was considered the primary endpoint. Major adverse cardiovascular and cerebrovascular events, including death, myocardial infarction, stroke, and subsequent mitral valve surgery, were considered secondary endpoints. Multivariable proportional hazards Cox regression models were used to assess the associations between groups and outcomes. In the sensitivity analysis we excluded patients who did not undergo coronary artery bypass graft and repeated the statistical analysis above.

RESULTS

The median follow-up time among all patients was 41 months. There was no significant difference between the left ventricular reconstruction plus mitral valve surgery and the left ventricular reconstruction groups with regard to all-cause mortality (P = .208) and major adverse cardiovascular and cerebrovascular events (P = .817) after adjustment for covariates. In the sensitivity analysis there was no significant difference between the left ventricular reconstruction plus mitral valve surgery and left ventricular reconstruction groups with regard to all-cause mortality (P = .158) and major adverse cardiovascular and cerebrovascular events (P = .651) after adjustment for covariates.

CONCLUSIONS

The clinical outcomes of left ventricular reconstruction are comparable with those of left ventricular reconstruction plus mitral valve surgery in patients with left aneurysm and moderate mitral regurgitation.

Clinical and echocardiographic factors associated with mitral plasticity in patients with chronic inferior myocardial infarction

Aims

Ischaemic mitral regurgitation (IMR) is consequence of left ventricular (LV) remodelling after myocardial infarction. In some cases, the mitral valve enlarges to compensate for LV remodelling and tenting, improving its coaptation; a process termed 'plasticity'. We sought to identify clinical and echocardiographic factors associated with plasticity in patients with chronic inferior myocardial infarction (CII).

Methods and results

This study included 91 revascularized CII patients and 46 controls. Plasticity and IMR severity were evaluated by 2D transthoracic echocardiography. Compared with controls, CII patients were older (59 vs. 25 years) and mostly men (80% vs. 46%), both P < 0.001. Chronic inferior myocardial infarction patients also had significant LV remodelling: larger LV volumes, larger mitral tenting areas, larger coaptation depths, longer mitral leaflets and chords, and worse mitral regurgitation (all P ≤ 0.03). Of 91 CII patients, 60 had mitral plasticity (longer anterior and posterior leaflets and longer posterior chords, all P < 0.001), despite not exhibiting significantly larger LV volumes, tenting area or coaptation depth, when compared with patients with no plasticity. Contralateral (anterior) papillary muscle-to-annulus length tended to be increased in CII plasticity patients (P = 0.05). Also they had less moderate and severe IMR (both P < 0.04) compared with non-plasticity CII patients. Multivariate analysis demonstrated independent associations between plasticity and smoking [odds ratio (OR) 0.03, 0.002-0.57; P = 0.019], duration of type-2 diabetes (OR 1.19, 1.007-1.42; P = 0.04) and haemoglobin (OR 2.17, 1.25-3.76; P = 0.005).

Conclusion

Mitral plasticity results in less moderate and severe IMR. Longer time-duration of diabetes mellitus and higher haemoglobin level are independently associated with mitral plasticity, while smoking independently associates with no plasticity. Increased anterior papillary muscle-to-annulus length in CII patients with plasticity suggests complex LV remodelling mechanisms are involved in plasticity.

Long-term results of surgical treatment of secondary severe mitral regurgitation in patients with end-stage heart failure: Advantage of prosthesis insertion

BACKGROUND

Surgical treatment of secondary mitral regurgitation (SMR) is controversial.

AIM

To analyse outcome after undersizing annuloplasty (UA) and mitral valve replacement (MVR).

METHODS

Consecutive patients operated on for severe SMR, with left ventricular ejection fraction (LVEF)<40% and refractory CHF, were included. Endpoints were in-hospital mortality, mid-term cardiovascular (CV) mortality, evolution of LV variables and recurrence of mitral regurgitation (MR).

RESULTS

59 patients were included (mean age 65±10 years, preoperative LVEF 36±6%; effective regurgitant orifice [ERO] 41±17 mm²), 41 with ischaemic disease: 12 underwent UA and 47 underwent MVR; only eight had concomitant coronary revascularization. In-hospital mortality was 3.3% (8.3% in UA group; 2.1% in MVR group). Eight-year CV mortality was 39±13% (40±18% in UA group; 27±10% in MVR group). Older age (hazard ratio 1.14, 95% confidence interval 1.07 to 1.22; P<0.001) and LV end-systolic diameter (hazard ratio 1.18, 95% confidence interval 1.09 to 1.27; P<0.001) independently predicted CV mortality. LVEF did not change between the preoperative and follow-up transthoracic echocardiograms in the MVR group (36±6% vs. 35±10%; P=0.6) or the UA group (36±5% vs. 31±12%; P=0.09). Conversely, LV end-diastolic diameter decreased significantly in the MVR group (64±8m to 59±9mm; P=0.002), but not in the UA group (61±7m to 64±10mm; P=0.2). Recurrence of significant MR occurred in 81% of patients in the UA group (mean postoperative ERO 19±6 mm²) versus none in the MVR group.

CONCLUSIONS

Surgical treatment of SMR can be performed with acceptable operative risk and mid-term survival in severe heart failure, even if there is no indication for revascularization. MVR is associated with significant reverse remodelling, and UA with prohibitive risk of MR recurrence.

Clinical manifestations, diagnosis, and treatment of ischemic mitral regurgitation: a review

Ischemic mitral regurgitation (IMR) is a frequent complication after acute myocardial infarction (AMI) associated with a worse prognosis. The pathophysiological mechanisms of IMR are not fully understood, but it is known to be a complex process in which ventricular remodelling is the main causal factor. The various imaging techniques in cardiology and echocardiography fundamentally have contributed significantly to clarify the mechanisms that cause and progressively aggravate IMR. At present, different therapeutic options, the most important of which are cardio-surgical, address this problem. Nowadays the improvement in cardiac surgery and transcatheter therapies, have shown a therapeutic advance in IMR management. IMR is a predictor of poor prognosis in patients with heart failure and depressed left ventricular (LV) systolic function. However, it remains controversial whether mitral regurgitation (MR) in these patients is a consequence of dilation and dysfunction of the LV, or whether it contributes to worsening the prognosis of the ventricular dysfunction. Given that echocardiography has a fundamental reference role in the identification, graduation of severity and evaluation of the therapeutics used in the treatment of MR, we are going to focus on it over the rest of the imaging techniques. In contrast to primary MR the benefits of mitral surgery in patients with secondary MR are uncertain. Therefore, we will comment fundamentally on the role of mitral surgery in patients with IMR, with an update of the different surgical interventions available, without forgetting to mention the other therapeutic options currently available.

Concomitant mitral valve surgery in patients with moderate ischemic mitral regurgitation undergoing coronary artery bypass grafting

Background

The clinical benefits of a concomitant mitral valve (MV) surgery in patients with moderate ischemic mitral regurgitation (iMR) undergoing coronary artery bypass grafting (CABG) remain controversial.

Methods

The study involved 710 patients (mean age, 65.0±8.9 years; 504 males) with moderate iMR undergoing CABG between 1990 and 2015. Of these, 116 (16.3%) patients underwent a concomitant MV surgery (MVS; replacement in 10, repair in 106) and 594 (83.7%) underwent CABG only. Clinical and echocardiographic outcomes were compared before and after adjustment with the use of propensity score (PS) analyses.

Results

Early mortality occurred in 22 (3.7%) and 13 (11.2%) patients in CABG-only and CABG with MVS group, respectively (P=0.001). After adjustment, CABG with MVS group showed significantly increased risks of early death (P<0.001), low cardiac output syndrome (LCOS) (P=0.001) and surgical bleeding (P=0.014). During a median follow-up of 78.0 months (quartile 1-3, 33.6-115.9 months), overall mortality occurred in 286 (40.3%) patients. The addition of an MV surgery showed an increased risk of overall mortality [hazard ratio (HR), 1.34; 95% confidence interval (CI), 0.99-1.80; P=0.055], which became comparable 1 year after surgery on landmark survival analysis (HR, 0.94; 95% CI, 0.64-1.39; P=0.772). Improved left ventricular (LV) ejection fraction and LV reverse remodeling were observed in both groups without significant intergroup differences.

Conclusions

The addition of a concomitant MV surgery increased the risk of early mortality and complications in patients with moderate iMR undergoing CABG. In long-term clinical and echocardiographic outcomes, a concomitant MV surgery seemed to confer no significant clinical benefits.

Predicting functional mitral stenosis after restrictive annuloplasty for ischemic mitral regurgitation

BACKGROUND

Although it has been realized that restrictive mitral valve annuloplasty (MVA) may re-sult in clinically significant functional mitral stenosis (MS), it still cannot be predicted. The purpose of this study was to identify risk factors for clinically significant functional MS following restrictive MVA surgery for chronic ischemic mitral regurgitation (CIMR).

METHODS

One hundred and fourteen patients who underwent restrictive MVA with coronary artery bypass grafting (CABG) for treatment of CIMR were retrospectively reviewed. Clinically significant functional MS was defined as resting transmitral peak pressure gradient (PPG) ≥ 13 mmHg.

RESULTS

During the follow-up period (range 6-12 months), 28 (24.56%) patients developed clinically significant functional MS. The PPG at follow-up was significantly higher than that measured in the early postoperative stage (3-5 days after surgery). Moreover, there was a linear correlation between the two measurements (r = 0.398, p < 0.001). Annuloplasty size ≤ 27 mm and early postoperative PPG ≥ 7.4 mmHg could predict clinically significant functional MS at 6-12 months postoperatively.

CONCLUSIONS

Chronic ischemic mitral regurgitation patients treated with restrictive MVA and CABG have significant increases in PPG postoperatively. Annuloplasty size ≤ 27 mm and early postopera-tive PPG ≥ 7.4 mmHg can predict clinically significant functional MS at 6-12 months after surgery.

Surgical Treatment of Ischemic Mitral Regurgitation: Valve Repair Versus Replacement

PURPOSE OF REVIEW

Ischemic mitral regurgitation (MR), which occurs in about 20-30% patients with a prior myocardial infarction, is associated with worsening heart failure and an increase in cardiovascular mortality. It should be treated surgically if certain hemodynamic severity criteria are met and in patients who continue to experience symptoms of heart failure despite optimal medical therapy. However, current guidelines do not suggest which of the available approaches to mitral valve surgery-mitral valve (MV) repair or replacement (MVR) is superior for this indication. While MV repair is reported to confer improved survival, MVR may provide higher rates of freedom from recurrent MR. This article attempts to provide the reader with a comprehensive review and comparison of current techniques of mitral valve surgery in patients with severe ischemic MR.

RECENT FINDINGS

The first randomized trial to compare MV repair versus MVR in patients with severe ischemic MR, the Cardiothoracic Surgical Trials Network (CTSN) trial, was recently concluded and reported no significant difference in the primary outcome of left ventricular end systolic volume index between the two approaches at either 1- or 2-year follow-ups. Data comparing approaches of MV repair and MVR for ischemic MR is largely limited to small, non-randomized retrospective trials. The only randomized trial data to examine this issue suggested no difference in mortality with either MVR or MV repair; however, MVR was shown to be consistently associated with higher rates of MR recurrence. Certain echocardiographic features have been reported to predict poor outcomes with MVR and may help refine the selection of the surgical approach in the individual patient.

Mitral annuloplasty ring suture forces: Impact of surgeon, ring, and use conditions

OBJECTIVE

The study objective was to quantify the effect of ring type, ring-annulus sizing, suture position, and surgeon on the forces required to tie down and constrain a mitral annuloplasty ring to a beating heart.

METHODS

Physio (Edwards Lifesciences, Irvine, Calif) or Profile 3D (Medtronic, Dublin, Ireland) annuloplasty rings were instrumented with suture force transducers and implanted in ovine subjects (N = 23). Tie-down forces and cyclic contractile forces were recorded and analyzed at 10 suture positions and at 3 levels of increasing peak left ventricular pressure.

RESULTS

Across all conditions, tie-down force was 2.7 ± 1.4 N and cyclic contractile force was 2.0 ± 1.2 N. Tie-down force was not meaningfully affected by any factor except surgeon. Significant differences in overall and individual tie-down forces were observed between the 2 primary implanting surgeons. No other factors were observed to significantly affect tie-down force. Contractile suture forces were significantly reduced by ring-annulus true sizing. This was driven almost exclusively by Physio cases and by reduction along the anterior aspect, where dehiscence is less common clinically. Contractile suture forces did not differ significantly between ring types. However, when undersizing, Profile 3D forces were significantly more uniform around the annular circumference. A suture's tie-down force did not correlate to its eventual contractile force.

CONCLUSIONS

Mitral annuloplasty suture loading is influenced by ring type, ring-annulus sizing, suture position, and surgeon, suggesting that reports of dehiscence may not be merely a series of isolated errors. When compared with forces known to cause suture dehiscence, these in vivo suture loading data aid in establishing potential targets for reducing the occurrence of ring dehiscence.

Surgical Management of Severe Ischaemic Mitral Regurgitation

BACKGROUND

Coronary artery bypass graft surgery (CABG) with mitral valve surgery is undisputed in severe ischaemic mitral regurgitation (IMR) treatment, but the controversy is whether mitral valve replacement (MVR) or mitral valvuloplasty (MVP) should be used.

METHODS

Data was collected from 130 cases of severe IMR patients who underwent CABG and MVP or MVR from June 2010 to June 2015 to compare the short-term efficacy of CABG with MVP or MVR in the treatment of severe IMR patients. There were 70 cases in the MVP group and 60 in the MVP group. The postoperative major cardiac cerebral vascular events and left ventricular ejection fraction (LVEF), left ventricular end-systolic diameter (LVESD), and left ventricular end-diastolic diameter (LVEDD) were recorded.

RESULTS

Eleven patients died in hospital, the remaining patients were followed up for 12 months; 18 patients died. The cumulative survival rate and the major cardiac cerebrovascular events were not significantly different. There was no significant change in LVEF, but LVEDD, LVESD and systolic pulmonary artery pressure (sPAP) improved significantly, and there was no difference between the groups. In the MVR group, the rate of postoperative moderate or severe mitral regurgitation patients was significantly less than that in the MVP group.

CONCLUSION

The short-term survival rate, reversal of left ventricular remodelling and major cardiac or cerebrovascular events post-CABG combined with MVP were not significantly different to those with CABG combined with MVR in the treatment of severe IMR, but long-term efficacy remains to be observed.

Topographic mapping of left ventricular regional contractile injury in ischemic mitral regurgitation

OBJECTIVE

Restrictive leaflet tethering resulting from regional left ventricular (LV) contractile injury causes ischemic mitral regurgitation (MR). We hypothesized that 3-dimensional LV topographic mapping by MRI-based multiparametric strain analysis could characterize the regional contractile injury patterns that differentiate ischemic coronary artery disease patients who have ischemic MR from those who do not.

METHODS

Magnetic resonance imaging-based multiparametric strain data were calculated for 15,300 LV grid points in 100 normal volunteers. Strain parameters from ischemic MR (n = 10) and ischemic no-MR (n = 36) patients were then normalized to this normal human strain database with z score quantification of standard deviation from the normal mean. Mean multiparametric strain z scores were calculated for 18 LV subregions (basilar/mid/apical levels; 6 LV regions). Mean strain z scores for papillary muscle-related (basilar/mid levels of anterolateral, posterolateral, and posterior) and nonpapillary muscle-related (all other) subregions were compared between ischemic MR and ischemic no-MR groups.

RESULTS

Across all patients, contractile injury was greater in the papillary muscle-related regions compared with the nonpapillary regions (P = .007). In the papillary regions, contractile injury was greater in the ischemic MR group compared with the no-MR group (z scores, 1.91 ± 1.13 vs 1.20 ± 1.01, respectively; P < .001). Strain values in the nonpapillary muscle-related subregions were not different between the 2 groups (1.31 ± 1.04 vs 1.20 ± 1.03; P = .301).

CONCLUSIONS

Multiparametric strain analysis demonstrated severe normalized contractile injury in the papillary muscle-related LV subregions in patients with ischemic MR. The mean degree of normalized injury approached 2 standard deviations and was significantly worse than the levels seen in ischemic no-MR patients.