Annular Remodeling in Chronic Ischemic Mitral Regurgitation: Ring Selection Implications (original) (raw)
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Annuloplasty ring selection for chronic ischemic mitral regurgitation: lessons from the ovine model
The Annals of Thoracic Surgery, 2003
the ovine model Annuloplasty ring selection for chronic ischemic mitral regurgitation: lessons from http://ats.ctsnetjournals.org/cgi/content/full/76/5/1556 located on the World Wide Web at: The online version of this article, along with updated information and services, is Print ISSN: 0003-4975; eISSN: 1552-6259. Southern Thoracic Surgical Association. Background. Chronic ischemic mitral regurgitation (CIMR) is poorly understood and repair operations are often unsatisfactory. This study elucidates the mechanism of CIMR in an ovine model. Methods. Sonomicrometry array localization measured the three-dimensional geometry of the mitral annulus and subvalvular apparatus in five sheep before and 8 weeks after a posterior infarction of the left ventricle that produced progressive severe CIMR. Results. End systolic annular area increased from 647 ؎ 44 mm 2 to 1,094 ؎ 173 mm 2 (p ؍ 0.01). Annular dilatation occurred equally along the anterior (47.0 ؎ 5.6 mm to 60.2 ؎ 4.9 mm, p ؍ 0.001) and posterior (53.8 ؎ 3.1 mm to 68.5 ؎ 8.4 mm, p ؍ 0.005) portions of the annulus. The tip of the anterior papillary muscle moved away from both the anterior and posterior commissures by 5.2 ؎ 3.2 mm (p ؍ 0.021) and 7.3 ؎ 2.2 mm (p ؍ 0.002), respectively. The distance from the tip of the posterior papillary muscle to the anterior commissure increased by 11.0 ؎ 5.7 mm (p ؍ 0.032) while the distance from the tip of the posterior papillary muscle to the posterior commissure remained constant.
European Journal of Cardio-Thoracic Surgery, 2006
Objective: Recent studies in animals showed that regional annulus distortion is a major determinant of ischemic mitral regurgitation (IMR) and accordingly suggested new surgical approaches with asymmetrical annuloplasty rings. As accurate measurement of annulus in patients is still a challenge, we performed this study to analyze the changes in three-dimensional annular geometry in patients with IMR compared to primary valvular lesions. Methods: We studied 110 patients divided into three groups: (1) 30 with coronary artery disease without IMR, (2) 38 with chronic IMR, and (3) 42 with MR due to primary valvular lesions. Longitudinal and septal-lateral annulus diameters; global diastolic and systolic annular area and its percentual shortening, diastolic and systolic areas of six regions corresponding to the segmental Carpentier classification were measured by 3D-echocardiography. The degree of MR was assessed by three-dimensional color Doppler. Global and regional left ventricular geometry were assessed by sphericity index and by measuring anterior and posterior tethering of papillary muscles. Results: Patients with significant IMR (group 2) showed larger longitudinal (52.7 AE 3.9 mm vs 41.8 AE 2.9 mm; p < 0.01) and antero-lateral (31.8 AE 3.5 mm vs 26.7 AE 2.8 mm; p < 0.01) annular diameters than the patients with MR due to primary valvular lesions (group 3). Diastolic (997.8 AE 64.9 mm 2 vs 700.7 AE 46.8 mm 2 ; p < 0.01) and systolic (894.9 AE 57.3 mm 2 vs 547.3 AE 35.0 mm 2 ; p < 0.01) annular areas were larger in group 2 than in group 3. Annular area change was significantly lower in the group with ischemic mitral regurgitation than in the group with primary valvular lesions (10.3 AE 1.1% vs 21.9 AE 1.6%; p < 0.01). Regional annular areas of the six sectors were homogeneously larger in group 2 than in group 3. The sector P3 did not show larger area than the other ones. The degree of MR, as assessed by the volumes of regurgitant jets, was higher in the group with primary valvular lesions than in the patients with IMR (32.6 AE 13.4 cm 3 vs 23.1 AE 11.1 cm 3 ; p < 0.01). Conclusions: This study showed that annular enlargement in patients with IMR affects the different annular regions to the same extent. An ideal surgical repair of IMR should be individually tailored after quantitative assessment measurement of geometry and function of each single component of the mitral valve complex.
Circulation, 2004
Background— Underlying left ventricular (LV) dysfunction contributes to poor survival after operation to correct ischemic mitral regurgitation (IMR). Many surgeons do not appreciate that a key component of the Bolling undersized mitral ring annuloplasty concept is to decrease LV wall stress by altering LV shape, but precise 3-dimensional (3-D) geometric data do not exist substantiating this effect. We tested the hypothesis that annular reduction decreases regional circumferential LV radius of curvature (ROC) in a model of acute IMR. Methods— Eight adult sheep underwent insertion of an adjustable Paneth-type annuloplasty suture and radiopaque markers on the LV and mitral annulus. The animals were studied with biplane videofluoroscopy during baseline conditions, then before and after tightening the annuloplasty suture during proximal left circumflex occlusion. End-systolic circumferential regional LV ROC and mitral annular area were computed. Results— Acute IMR was eliminated (MR grad...
Regional and Global Patterns of Annular Remodeling in Ischemic Mitral Regurgitation
The Annals of Thoracic Surgery, 2007
Background. The mammalian mitral annulus is saddle shaped. Experimental studies have shown that loss of saddle shape occurs in ischemic mitral regurgitation. However, neither the temporal pattern of global annular remodeling nor the geometric pattern of regional annular remodeling has been described. We sought to characterize these changes using real-time three-dimensional echocardiography in an ovine model.
European Journal of Cardio-thoracic Surgery, 2002
Objective: Annuloplasty rings are used to treat ischemic mitral regurgitation (IMR), but their exact effects on 3-D geometry of the overall mitral valve complex during acute left ventricular (LV) ischemia remain unknown. Methods: Radiopaque markers were sutured to the mitral leaflet edges, annulus, papillary muscle tips, and ventricle in three groups of sheep. One group served as control (n ¼ 5), and the others underwent Duran (n ¼ 6) or Physio (n ¼ 5) ring annuloplasty. One week later, 3-D marker coordinates at end-systole were obtained before and during balloon occlusion of the circumflex artery. Results: In all control animals, acute LV ischemia was associated with: (i) septallateral separation of the leaflet edges, which was predicted by lateral displacement of the lateral annulus during septal-lateral mitral annular dilatation; (ii) apical restriction of the posterior leaflet edge, which was predicted by displacement of the lateral annulus away from the nonischemic anterior papillary muscle; (iii) displacement of the posterior papillary muscle, which was not predictive of either septal-lateral leaflet separation or leaflet restriction; and (iv) mitral regurgitation. In the Duran group during ischemia, the posterior leaflet edge shifted posteriorly due to posterior movement of the lateral annulus, but no IMR occurred. In the Physio group during ischemia, neither the posterior leaflet edge nor the lateral annulus changed positions, and there was no IMR. In both the Duran and Physio groups, displacement of the posterior papillary muscle did not lead to IMR. Conclusions: Either annuloplasty ring prevented the perturbations of mitral leaflet and annular -but not papillary muscle tip -3-D geometry during acute LV ischemia. By fixing the septal-lateral annular dimension and preventing lateral displacement of the lateral annulus, annuloplasty rings prevented systolic septal-lateral leaflet separation and posterior leaflet restriction, and no acute IMR occurred. The flexible ring allowed posterior displacement of the posterior leaflet edge and the lateral annulus, which was not observed with a semi-rigid ring. q
Will a Partial Posterior Annuloplasty Ring Prevent Acute Ischemic Mitral Regurgitation?
Circulation, 2002
Background Acute posterolateral ischemia in sheep results in ischemic mitral regurgitation (IMR). While complete ring annuloplasty prevents acute IMR, partial annuloplasty rings may offer a more physiologic repair, but are untested in animal models of IMR. Methods Radiopaque markers were placed on the LV, mitral annulus (MA), and leaflets in 13 sheep. Seven sheep served as controls, and 6 had a St. Jude Tailor partial flexible ring implanted (29 mm in 5, 31 mm in 1). After 8±1 day, the animals were studied with biplane videofluoroscopy and echocardiography before and during acute posterolateral LV ischemia (balloon occlusion of circumflex artery). Mitral annular area (MAA), septal-lateral annular diameter (SL), annular perimeters, and leaflet edge separation were calculated from 3-D marker coordinates. Results The average degree of mitral regurgitation increased from 0.0±0.0 to 2.1±0.7 ( P =0.0006) in the control group during acute ischemia but remained unchanged in the Tailor group...
The effects of ring annuloplasty on mitral leaflet geometry during acute left ventricular ischemia
The Journal of Thoracic and Cardiovascular Surgery, 2000
Background: The perturbed mitral leaflet geometry that leads to acute ischemic mitral regurgitation during acute left ventricular ischemia has not been quantified, nor is it known whether annuloplasty rings affect these detrimental changes in leaflet geometry. Methods: Radiopaque markers were implanted on both mitral leaflets and around the anulus in 3 groups of sheep: one group without rings served as the control group (n = 7); the others underwent Duran (n = 6; Medtronic Heart Valve Division, Minneapolis, Minn) or Carpentier-Edwards Physio (n = 5; Baxter Cardiovascular Division, Santa Ana, Calif) ring annuloplasty. After recovery, 3-dimensional marker coordinates were obtained by means of biplane videofluoroscopy before and during acute posterolateral left ventricular ischemia. Leaflet geometry was defined by measuring distances between annular and leaflet markers and perpendicular distances to the leaflet markers from a best-fit annular plane. Results: In all control animals, left ventricular ischemia was associated with acute ischemic mitral regurgitation and apical displacement (away from the annular plane) of the posterior leaflet edge and base markers by 0.6 ± 0.4 mm (P = .01) and 0.7 ± 0.2 mm (P < .001), respectively. The distance between the posterior leaflet markers and the mid-posterior anulus did not change significantly during ischemia. The anterior leaflet edge marker extended 1.0 ± 0.5 mm (P = .01) away from the mid-anterior anulus during ischemia, but compared with its nonischemic position, the anterior leaflet was not displaced apically away from the annular plane. In all animals in the Duran and Physio groups, leaflet geometry was unchanged during ischemia, and acute ischemic mitral regurgitation was not detected. Conclusion: Acute ischemic mitral regurgitation was associated with restricted motion of the posterior leaflet and extension of the anterior leaflet. Annuloplasty rings prevented these geometric perturbations of the mitral leaflets during acute left ventricular ischemia and preserved valvular competence.
Effects of acute ischemic mitral regurgitation on three-dimensional mitral leaflet edge geometry☆☆☆
European Journal of Cardio-Thoracic Surgery, 2008
Background: Improved quantitative understanding of in vivo leaflet geometry in ischemic mitral regurgitation (IMR) is needed to improve reparative techniques, yet few data are available due to current imaging limitations. Using marker technology we tested the hypotheses that IMR (1) occurs chiefly during early systole; (2) affects primarily the valve region contiguous with the myocardial ischemic insult; and (3) results in systolic leaflet edge restriction. Methods: Eleven sheep had radiopaque markers sutured as five opposing pairs along the anterior (A 1-E 1) and posterior (A 2-E 2) mitral leaflet free edges from the anterior commissure (A 1-A 2) to the posterior commissure (E 1-E 2). Immediately postoperatively, biplane videofluoroscopy was used to obtain 4D marker coordinates before and during acute proximal left circumflex artery occlusion. Regional mitral orifice area (MOA) was calculated in the anterior (Ant-MOA), middle (Mid-MOA), and posterior (Post-MOA) mitral orifice segments during early systole (EarlyS), mid systole (MidS), and end systole (EndS). MOA was normalized to zero (minimum orifice opening) at baseline EndS. Tenting height was the distance of the midpoint of paired markers to the mitral annular plane at EndS. Results: Acute ischemia increased echocardiographic MR grade (0.5 AE 0.3 vs 2.3 AE 0.7, p < 0.01) and MOA in all regions at EarlyS, MidS, and EndS: Ant-MOA (7 AE 10 vs 22 AE 19 mm 2 , 1 AE 2 vs18 AE 16 mm 2 , 0 vs 17 AE 15 mm 2); Mid-MOA (9 AE 13 vs 25 AE 17 mm 2 , 3 AE 6 vs 21 AE 19 mm 2 , 0 vs 25 AE 17 mm 2); and Post-MOA (8 AE 10 vs 25 AE 16, 2 AE 4 vs 22 AE 13 mm 2 , 0 vs 23 AE 13 mm 2), all p < 0.05. There was no change in MOA throughout systole (EarlyS vs MidS vs EndS) during baseline conditions or ischemia. Tenting height increased with ischemia near the central and the anterior commissure leaflet edges (B 1-B 2 : 7.1 AE 1.8 mm vs 7.9 AE 1.7 mm, C 1-C 2 : 6.9 AE 1.3 mm vs 8.0 AE 1.5 mm, both p < 0.05). Conclusions: MOA during ischemia was larger throughout systole, indicating that acute IMR in this setting is a holosystolic phenomenon. Despite discrete postero-lateral myocardial ischemia, Post-MOA was not disproportionately larger. Acute ovine IMR was associated with leaflet restriction near the central and the anterior commissure leaflet edges. This entire constellation of annular, valvular, and subvalvular ischemic alterations should be considered in the approach to mitral repair for IMR.