Experimental evaluation of different chordal preservation methods during mitral valve replacement

Moon, Marc R.; DeAnda, Abelardo; Daughters, George T.; Ingels, Neil B.; Miller, D. Craig

doi:10.1016/0003-4975(94)90436-7

Cited by 85 publications

(55 citation statements)

References 21 publications

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“…By abolishing normal annular dynamic motion, 20 annuloplasty rings also damp subvalvular dynamics. During acute ischemia, these rings prevent ischemic dilation of the annulus and therefore, prevent ischemic repositioning of the papillary tips and systolic tethering of the leaflets.…”

Section: Discussionmentioning

confidence: 99%

“…Although epicardial LV volume calculated in this manner overestimates true LV chamber volume, the change in epicardial LV volume is an accurate measurement of the relative change in LV chamber volume. 20 Thus, stroke volume is accurately calculated from the change in epicardial LV volume, but ejection fraction (EF), or stroke volume normalized to epicardial LV end-diastolic volume, is substantially underestimated.…”

Section: Systolic Functionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Systolic Functionmentioning

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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“…During each cardiac cycle, end-systole was defined as the time of the videofluoroscopic frame containing the point of peak negative rate of left ventricular pressure fall (-dP/dt), and end-diastole as the videofluoroscopic frame containing the peak of the ECG R-wave. Instantaneous left ventricular volume was calculated from the positions of the epicardial LV markers and annular markers using a space-filling multiple tetrahedral volume method for each frame, ie, every 16.7 ms. 11 Although myocardial volume is included in calculation of left ventricular volume, relative changes in left ventricular chamber size are accurately reflected. 11…”

Section: Hemodynamics and Cardiac Cycle Timingmentioning

confidence: 99%

Geometric Distortions of the Mitral Valvular-Ventricular Complex in Chronic Ischemic Mitral Regurgitation

et al. 2003

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Background— Better understanding of the precise 3-dimensional geometric changes of the mitral valvular-ventricular complex in chronic ischemic mitral regurgitation (CIMR) is needed in order to devise better surgical repair techniques. We hypothesized that changes after inferior myocardial infarction would be different in hearts that developed CIMR compared with those that did not. Methods and Results— Twenty-four sheep underwent coronary snare and marker placement (annulus, papillary muscles, and anterior and posterior leaflets). After 8 days, cinefluoroscopy provided 3-dimensional marker data, and snare occlusion of obtuse marginal branches created inferior myocardial infarction, including the posterior papillary muscle. After 7 weeks, the 16 surviving animals were studied again and grouped by mitral regurgitation grade (≥ 2+, n=10 versus ≤ 1+, n=6). End-systolic mitral annulus dimensions, components of papillary muscle and leaflet displacement, were calculated. After inferior myocardial infarction, total displacement of the posterior papillary muscle from the midseptal annulus (“saddle horn”) was greater in CIMR(+) animals: 6.5±3.2 versus 3.1±2.7 ( P =0.02), with the posterior papillary muscle moving more laterally (6.8±3.4 versus 2.5±3.5 mm, P =0.01). Increase in mitral annular septal-lateral diameter was greater in animals with CIMR (4.9±2.7 versus 2.3±2.0, P =0.02), and apical displacement of the posterior leaflet (PL) margin was also greater in the CIMR(+) group (1.7±1.0 versus 0.3±0.5, P =0.01). Conclusions— The CIMR(+) group had greater septal-lateral annular dilatation, lateral posterior papillary muscle displacement, and apical PL restriction, indicating that these associated geometric alterations may be important in the pathogenesis of CIMR. Treatment of CIMR should address both annular septal-lateral dilatation and lateral displacement of the posterior papillary muscle.

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“…5,22,23 Several different subvalvular-preservation techniques have been described. [6][7][8][9] Some authors advocate complete preservation of the mitral valve apparatus over partial preservation. 16,24 In an experimental study, Hansen and associates 25 proposed that the apparatus of the anterior leaf let is more important than that of the posterior leaf let; however, another experimental study found no substantial difference between anterior and posterior chordal-sparing techniques.…”

Section: Discussionmentioning

confidence: 99%

“…Various approaches to subvalvular apparatus preservation have been developed. [6][7][8][9] Papillary muscle repositioning (PMR) is a subvalvular apparatus-sparing method that can be applied to both the anterior and posterior mitral annulus. In patients with LV dysfunction and mitral regurgitation, several studies 10,11 have shown favorable effects of papillary muscle repositioning on LV remodeling; however, the effect of subvalvular-apparatus-sparing surgery (including PMR) on LV mechanics has not yet been fully elucidated in patients who have isolated mitral stenosis and preserved LV function.…”

mentioning

confidence: 99%

Papillary Muscle Repositioning as a Subvalvular Apparatus Preservation Technique in Mitral Stenosis Patients with Normal Left Ventricular Systolic Function

Lafçı¹,

Çağlı²,

Çiçek³

et al. 2014

Texas Heart Institute Journal

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Subvalvular apparatus preservation is an important concept in mitral valve replacement (MVR) surgery that is performed to remedy mitral regurgitation. In this study, we sought to determine the effects of papillary muscle repositioning (PMR) on clinical outcomes andM itral valve replacement (MVR) with a mechanical or a bioprosthetic valve is one of the most performed cardiac surgical procedures. Although in recent years valve repair has usually been preferred to replacement, MVR is inevitable when repair is not feasible. After MVR, low cardiac output syndrome develops in some patients, because the subvalvular apparatus has not been spared. 1Because the subvalvular apparatus provides continuity between the mitral annulus and the left ventricular (LV) wall through the leaflets, chordae tendineae, and papillary muscles, it plays an important role in LV function.2 Several studies 3-5 have shown that protection of the subvalvular apparatus during MVR can decrease the risk of low cardiac output syndrome, reduce the operative mortality rate, and improve postoperative LV systolic function. Various approaches to subvalvular apparatus preservation have been developed. [6][7][8][9] Papillary muscle repositioning (PMR) is a subvalvular apparatus-sparing method that can be applied to both the anterior and posterior mitral annulus. In patients with LV dysfunction and mitral regurgitation, several studies 10,11 have shown favorable effects of papillary muscle repositioning on LV remodeling; however, the effect of subvalvular-apparatus-sparing surgery (including PMR) on LV mechanics has not yet been fully elucidated in patients who have isolated mitral stenosis and preserved LV function.

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Experimental evaluation of different chordal preservation methods during mitral valve replacement

Cited by 85 publications

References 21 publications

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

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

Geometric Distortions of the Mitral Valvular-Ventricular Complex in Chronic Ischemic Mitral Regurgitation

Papillary Muscle Repositioning as a Subvalvular Apparatus Preservation Technique in Mitral Stenosis Patients with Normal Left Ventricular Systolic Function

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