Mechanism of recurrent ischemic mitral regurgitation after annuloplasty: Continued LV remodeling as a moving target

Ischemic mitral regurgitation (IMR) is a frequent complication in the patients after acute myocardial infarction (AMI) or in ischemic cardiomyopathy (ICM), associated with significant prognosis worsening. Mitral valve (MV) involvement may be primary (organic MR) or secondary (functional MR). Primary MR develops because of mitral subvalvular apparatus rupture as an AMI complication. Secondary IMR develops in the conditions of normal MV cusps and chords structure because of balance impairment between MV closure and tension forces secondary to left ventricle (LV) geometry alterations. According to evidence data both scenarios of IMR are associated with at least one major coronary artery critical stenosis (>70%). Secondary IMR is the most frequent consequence of ischemic cardiomyopathy. IMR diagnosis is associated with elevated patients mortality compared to those without it. It has been shown, that survival within patients with IMR after AMI down to 40% in case of moderate-to-severe IMR, compared to 62% in the patients with mild IMR or 84% in the patients without IMR at all. Pathophysiological mechanisms of IMR are not fully understood, but it is well known, that IMR is a complex entity, having left chambers, especially left ventricle (LV) remodeling as a key cause. Echocardiography (EchoCG) significantly contributes to understanding the underlying mechanisms of IMR. The aim of this review is to summarize modern evidence based data about IMR mechanisms and analysis of contemporary EchoCG indices for diagnosis, evaluation and risks stratification in the patients with IMR. IMR develops in approximately 20% of patients after AMI with increasing occurrence over past years, significantly influencing patients’ prognosis. IMR is a complex and dynamic entity, where LV remodeling is the main factor of MV dysfunction. EchoCG plays the clue role in IMR diagnosis giving the detailed information about its mechanisms and severity grading. Comprehensive EchoCG in the patients with coronary arteries disease (CAD) allows a better and comprehensive approach in risks stratification and optimal surgical IMR treatment planning.

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Abstract 2265: Injection of a Biomaterial Polymer Results in Reverse Remodeling of Displaced Papillary Muscles and Reduction in Acute Ischemic Mitral Regurgitation

Circulation ◽

10.1161/circ.116.suppl_16.ii_494-a ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Judy Hung ◽

Jorge Solis ◽

J. L Guerrero ◽

Gavin Braithwaite ◽

Orhun K Muratoglu ◽

...

Keyword(s):

Mitral Regurgitation ◽

Mitral Annulus ◽

Left Ventricular ◽

Ischemic Mitral Regurgitation ◽

Reverse Remodeling ◽

Inert Material ◽

Stroke Work ◽

Polymer Injection ◽

Vena Contracta ◽

Lv Remodeling

Ischemic mitral regurgitation (IMR) relates to papillary muscle (PM) displacement caused by left ventricular (LV) distortion. We tested the hypothesis that displaced PMs can be repositioned by injection of polyvinyl-alcohol (PVA) polymer, a biologically inert material specially formulated to produce an encapsulated, stable, resilient gel once injected into the myocardium. The aim is to alter the compliance of infarcted myocardium and realign the displaced PMs. Methods : 9 sheep underwent circumflex branch ligation to produce acute IMR. PVA polymer was then injected by echo guidance into the myocardium underlying the infarcted PM. Hemodynamic data, EF, Elastance (Emax), preload-recruitable stroke work (PRSW), relaxation constant tau, and echo data were measured post IMR and post PVA injection. Results : One animal died after coronary ligation and 2 had no IMR; MR was moderate in the remaining 6. PVA injection decreased MR vena contracta from 5±0.4mm to 2±0.7mm (p<0.0001), with decreased tethering distance from infarcted PM to mitral annulus (27±4 to 24±4mm, p<0.001). PVA injection did not significantly decrease EF (43±6% vs 37±4%, post IMR vs post PVA, p=ns), Emax (1.5±0.53 vs 1.6±0.42), PRSW (33±12 vs 31±5) or tau (63±49 ms vs 70±25 ms). Conclusions : PVA polymer injection can acutely reverse LV remodeling to reposition displaced PMs and decrease IMR without adverse effects on LV systolic or diastolic function. This new approach (to alter pathologic anatomy) offers an alternative for relieving IMR by correcting PM position, thus relieving tethering that causes IMR.

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Ischemic Mitral Regurgitation: A Multifaceted Syndrome with Evolving Therapies

Biomedicines ◽

10.3390/biomedicines9050447 ◽

2021 ◽

Vol 9 (5) ◽

pp. 447

Author(s):

Mattia Vinciguerra ◽

Francesco Grigioni ◽

Silvia Romiti ◽

Giovanni Benfari ◽

David Rose ◽

...

Keyword(s):

Myocardial Infarction ◽

Mitral Regurgitation ◽

Structural Changes ◽

Current Knowledge ◽

Ischemic Mitral Regurgitation ◽

Surgical Approaches ◽

Severe Mitral Regurgitation ◽

Chronic Ischemia ◽

Lv Remodeling ◽

Specific Influence

Dysfunction of the left ventricle (LV) with impaired contractility following chronic ischemia or acute myocardial infarction (AMI) is the main cause of ischemic mitral regurgitation (IMR), leading to moderate and moderate-to-severe mitral regurgitation (MR). The site of AMI exerts a specific influence determining different patterns of adverse LV remodeling. In general, inferior-posterior AMI is more frequently associated with regional structural changes than the anterolateral one, which is associated with global adverse LV remodeling, ultimately leading to different phenotypes of IMR. In this narrative review, starting from the aforementioned categorization, we proceed to describe current knowledge regarding surgical approaches in the management of IMR.

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Prior Angina Reduces Ischemic Mitral Regurgitation in Patients with ST-Elevation Myocardial Infarction, Role of Ischemic Preconditioning

10.21203/rs.3.rs-172779/v1 ◽

2021 ◽

Author(s):

Ramime Ozel ◽

Pelin Karaca Ozer ◽

Nail Guven Serbest ◽

Adem Atıcı ◽

Imran Onur ◽

...

Keyword(s):

Myocardial Infarction ◽

Mitral Regurgitation ◽

Ischemic Preconditioning ◽

Troponin T ◽

Left Ventricular ◽

Ischemic Mitral Regurgitation ◽

Proximal Isovelocity Surface Area ◽

Lv Remodeling ◽

St Elevation ◽

Regurgitant Orifice Area

Abstract BackgroundMitral regurgitation may develop due to left ventricular (LV) remodeling within 3 months following acute myocardial infarction (AMI) and is called ischemic mitral regurgitation (IMR). Ischemic preconditioning (IPC) has been reported as the most important mechanism of the association between prior angina and the favorable outcome. The aim of this study was to investigate the effect of prior angina on the development and severity of IMR at 3rd month in patients with ST elevation MI (STEMI).MethodsFourty five (45) patients admitted with STEMI and at least mild IMR, revascularized by PCI were enrolled. According to presence of prior angina within 72 hours before STEMI, patients were then divided into two groups as angina (+) (n:26; 58%) and angina (-) (n:19; 42%). All patients underwent 2D transthoracic echocardiography at 1st, 3rd days and 3rd month. IMR was evaluated by proximal isovelocity surface area (PISA) method: PISA radius (PISA-r), effective regurgitant orifice area (EROA), regurgitant volume (Rvol). LV ejection fraction (EF %) was calculated by Simpson’s method. High sensitive troponin T (hs-TnT), creatine phosphokinase myocardial band (CK-MB) and N-terminal pro-brain natriuretic peptid (NTpro-BNP) levels were compared between two groups.ResultsAlthough PISA-r, EROA and Rvol were similar in both groups at 1st and 3rd days, all were significantly decreased (p=0.012, p=0.007, p=0.011, respectively) and EF was significantly increased (p< 0.001) in angina (+) group at 3rd month. NTpro-BNP and hs-TnT levels at 1st day and 3rd month were similar, however CK-MB level at 3rd month was found to be significantly lower in the angina (+) group (p=0.034).ConclusionAt the end of the 3rd month, it was observed that the severity of IMR evaluated by PISA method was decreased and EF increased significantly in patients who defined angina within 72 hours prior to STEMI, suggesting a relation with IPC.

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