Mechanism of ischemic mitral regurgitation. An experimental evaluation.

Kaul, Sanjiv; Spotnitz, William D.; Glasheen, William P.; Touchstone, Dale A.

doi:10.1161/01.cir.84.5.2167

Cited by 238 publications

(130 citation statements)

References 36 publications

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“…Significant MR is not uncommon in the failing and/or large ventricle, and our clinical echocardiographic findings support prior experimental studies relating MR in the setting of ischemia/infarction to incomplete leaflet closure. 22 This apical displacement of the closure point of the leaflets can be due to displacement of the papillary muscles caused by LV enlargement and/or altered LV geometry 23,24 or inadequate closure forces generated in systole by the failing ventricle. 25 Although it is difficult to directly compare our patients in shock to more stable post-MI populations, angiographic studies of patients both early 26 and late 27 after MI have shown that significant MR is an independent predictor of poorer outcome.…”

Section: Discussionmentioning

confidence: 99%

Echocardiographic Predictors of Survival and Response to Early Revascularization in Cardiogenic Shock

et al. 2003

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for the SHOCK Trial Background-Although echocardiography is used in diagnosis and management of myocardial infarction, it has not been established whether specific features of cardiac structure or function early in the course of cardiogenic shock provide prognostic value. The purposes of this substudy of the SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK (SHOCK) trial were to describe the echocardiographic features of cardiogenic shock, identify findings on early echocardiograms associated with outcome, examine the interaction of such features with treatment, and determine whether these features could provide insights into the survival benefit observed with early revascularization and guide selection of patients for this strategy. Methods and Results-One hundred seventy-five echocardiograms performed within 24 hours of randomization to the early revascularization (ERV) or initial medical stabilization (IMS) arms of the trial were submitted for quantitative assessment, and 169 were suitable for analysis. The 2 groups were similar in terms of clinical and early echocardiographic characteristics. Mean left ventricular ejection fraction (LVEF) was 31%, and moderate or greater mitral regurgitation (MR) was noted in 39.1%. On multivariate analysis, the only independent predictors of survival were MR severity and LVEF. A survival benefit for the ERV strategy was observed at all levels of LVEF and MR. Conclusions-A wide range of cardiac structural and functional abnormalities exists in patients presenting with acute cardiogenic shock. Both short-and long-term mortality appear to be associated with initial left ventricular systolic function and MR as assessed by echocardiography, and a benefit of ERV is noted regardless of baseline LVEF or MR.

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Section: Discussionmentioning

confidence: 99%

Echocardiographic Predictors of Survival and Response to Early Revascularization in Cardiogenic Shock

et al. 2003

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“…Because of the complexity of the mitral valve complex, many investigators have focused on isolated changes of specific substructures to begin to understand the factors that predispose to IMR. The proposed mechanisms range from theories of ischemia-induced deformation of the mitral annulus, 1,2 disturbances in papillary muscle dynamics, 3,4 and primary changes in LV shape and contractility [5][6][7][8] to theories that develop an integrated mechanism of LV contractility and mitral valve function 9,10 or of regional LV geometry and mitral valve function. [11][12][13] These disparate findings attest to our ignorance of this vexing problem.…”

mentioning

confidence: 99%

Coordinate-Free Analysis of Mitral Valve Dynamics in Normal and Ischemic Hearts

Dagum¹,

Timek²,

Green³

et al. 2000

Circulation

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Background-The purpose of this investigation was to study mitral valve 3D geometry and dynamics by using a coordinate-free system in normal and ischemic hearts to gain mechanistic insight into normal valve function, valve dysfunction during ischemic mitral regurgitation (IMR), and the treatment effects of ring annuloplasty. Methods and Results-Radiopaque markers were implanted in sheep: 9 in the ventricle, 1 on each papillary tip, 8 around the mitral annulus, and 1 on each leaflet edge midpoint. One group served as a control (nϭ7); all others underwent flexible Tailor partial (nϭ5) or Duran complete (nϭ6) ring annuloplasty. After an 8Ϯ2-day recovery, 3D marker coordinates were measured with biplane videofluoroscopy before and during posterolateral left ventricular ischemia, and MR was assessed by color Doppler echocardiography. Papillary to annular distances remained constant throughout the cardiac cycle in normal hearts, during ischemia, and after ring annuloplasty with either type of ring. Papillary to leaflet edge distances similarly remained constant throughout ejection. During ischemia, however, the absolute distances from the papillary tips to the annulus changed in a manner consistent with leaflet tethering, and IMR was observed. In contrast, during ischemia in either ring group, those distances did not change from preischemia, and no IMR was observed. Conclusions-This analysis uncovered a simple pattern of relatively constant intracardiac distances that describes the 3D geometry and dynamics of the papillary tips and leaflet edges from the dynamic mitral annulus. Ischemia perturbed the papillary-annular distances, and IMR occurred. Either type of ring annuloplasty prevented such changes, preserved papillary-annular distances, and prevented IMR.

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“…Острая ми-тральная регургитация (ОМР) чаще всего возникает при окклюзиях правой коронарной или огибающей артерий, приводящих к нижнему инфаркту, отрыву папиллярных мышц и ненормальному движению базальных отделов и нижней стенки ЛЖ. Хроническая ишемия в бассейне все той же самой правой коронарной артерии ввиду «отстава-ния» нижней стенки ЛЖ может также приводить к значи-мым нарушениям работы аппарата МК даже у пациентов с нормальной сократимостью ЛЖ [2,3].…”

Section: механизмы развития имрunclassified

“…Ишемическая ми-тральная регургитация (ИМР) -это недостаточность ми-трального клапана (МК), возникшая вследствие инфар-кта миокарда (ИМ) или его хронической ишемии. ИМР может быть острая, возникшая вследствие отрыва папил-лярной мышцы, или хроническая, механизмом развития которой являются дисфункция папиллярных мышц, не-синхронное сокращение миокарда и, как следствие, не-скоординированная работа аппарата МК или расширение камер сердца с дилатацией фиброзного кольца (ФК) и не-достаточной коаптацией створок МК [1][2][3].…”

unclassified

“…Это в большинстве случаев не влияет на стратегию лечения, но правильное понимание патофи-зиологии ИМР позволяет принять правильное решение о способе и вариантах лечения. Поэтому функциональ-ную MP ишемического генеза следует отличать от орга-КАРДИОЛОГИЯ И СЕРДЕЧНО-СОСУДИСТАЯ ХИРУРГИЯ, 3,2015 нической митральной недостаточности, имеющей в ос-нове дегенеративную, ревматическую, врожденную или инфекционную этиологии. Также необходимо отличать MP ишемического генеза от функциональной MP при идиопатической дилатационной кардиомиопатии [24,25].…”

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