Altered collagen concentration in mitral valve leaflets: biochemical and finite element analysis

Kunzelman, Karyn S.; Quick, David W.; Cochran, Richard P.

doi:10.1016/s0003-4975(98)01106-0

Cited by 100 publications

(86 citation statements)

References 8 publications

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“…Increased leaflet stress has been linked to leaflet thickening and collagen deposition that may additionally perturb leaflet motion and closure dynamics. 27,28 In contrast, Paneth suture tightening, even beyond the amount required to restore mitral competence, had no apparent deleterious impact on either anterior or posterior mitral leaflet excursion.…”

Section: Discussionmentioning

confidence: 95%

Paneth Suture Annuloplasty Abolishes Acute Ischemic Mitral Regurgitation but Preserves Annular and Leaflet Dynamics

Tibayan

Rodriguez²,

Liang³

et al. 2003

Circulation

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Background-Ring annuloplasty, the standard treatment for ischemic mitral regurgitation (IMR), abolishes normal annular dynamics and freezes the posterior leaflet. We examined the impact of Paneth suture annuloplasty during acute IMR on motion of the mitral annulus and leaflets in an ovine model. Methods and Results-Eight sheep had radiopaque markers placed on the left ventricle, anterior mitral leaflet, posterior mitral leaflet, and mitral annulus. A Paneth suture annuloplasty that could be reversibly tightened was anchored to each fibrous trigone and externalized through the mid-lateral mitral annulus. Acute IMR was induced by proximal circumflex artery occlusion. Transesophageal echocardiography assessed the degree of IMR, and biplane cinefluoroscopy measured 3-dimensional marker coordinates before and during circumflex ischemia, and tightening of the Paneth suture. Paneth suture annuloplasty eliminated acute IMR, and reduced septal-lateral and commissure-commissure mitral annular dimensions. Tightening of the annuloplasty sutures, even beyond the degree necessary to eliminate mitral regurgitation (MR), did not reduce septal-lateral or commissure-commissure annular shortening, shortening of the muscular annular perimeter, annular flexion, or angular excursion of the anterior or posterior leaflets relative to ischemic conditions. Conclusions-In contrast to ring annuloplasty, annular reduction sufficient to restore mitral competence during acute IMR can be achieved with a Paneth suture annuloplasty while simultaneously maintaining normal annular and leaflet dynamic motion. These findings should prompt additional investigation and design of repair methods that preserve the mobility of the mitral apparatus.

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Section: Discussionmentioning

confidence: 95%

Paneth Suture Annuloplasty Abolishes Acute Ischemic Mitral Regurgitation but Preserves Annular and Leaflet Dynamics

Tibayan

Rodriguez²,

Liang³

et al. 2003

Circulation

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“…PM elongation and prolapse, although uncommon, respond to PM and leaflet reduction. 38 Kunzelman et al 84 have shown by elegant finite element modeling that tethering stresses alter collagen deposition and increase leaflet stiffness, but the body appears unable to compensate sufficiently by increasing leaflet area. Leaflet elongation can reduce MR but is seldom attempted, perhaps because of concerns regarding durability, calcification, and complexity.…”

Section: Therapymentioning

confidence: 99%

Ischemic Mitral Regurgitation on the Threshold of a Solution

2005

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“…Since the mitral and tricuspid valves possess significant structural and anatomic differences between leaflets, all experiments used the larger anterior (mitral) and posterior (tricuspid) leaflets. The mitral valve anterior leaflet experiences higher in vivo stresses compared with the posterior leaflet (24,25). However, there is no evidence to suggest that the tricuspid valve leaflets differ in mechanical loading conditions.…”

Section: Tissue Harvest and Sample Preparationmentioning

confidence: 99%

Pregnancy-induced remodeling of heart valves

Pierlot

Moeller

Lee

et al. 2015

American Journal of Physiology-Heart and Circulatory Physiology

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Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves. HEART VALVES ARE COMPLEX and dynamic biological structures. They play important roles toward efficient cardiac pumping, ensuring unidirectional blood flow while opening and closing 3 billion times in a lifetime. The extent and the mechanisms via which the valves may adapt to changing loading conditions in either physiology or pathology remain unclear. Many investigations of valve adaptation have focused on physiological development (8,20,(51)(52)(53) or pathological conditions such as left ventricular (LV) dysfunction (10), mitral valve regurgitation (58), myxomatous degeneration (19), or heart failure (17). Recent studies from our laboratory, however, have demonstrated the capacity of maternal heart valve leaflets to remodel under the altered hemodynamics of pregnancy, a nonpathological condition (38,39,60). Pregnancy is accompanied by an increase in blood volume and cardiac output of ϳ50%, as the maternal circulation accommodates the developing fetoplacental unit. This volume overload produces cardiac enlargement (21, 45, 60) with expansion of valve orifices (areas increasing from 12-53% in humans; see Refs. 9 and 43). These changes in geometry then elevate...

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Altered collagen concentration in mitral valve leaflets: biochemical and finite element analysis

Cited by 100 publications

References 8 publications

Paneth Suture Annuloplasty Abolishes Acute Ischemic Mitral Regurgitation but Preserves Annular and Leaflet Dynamics

Paneth Suture Annuloplasty Abolishes Acute Ischemic Mitral Regurgitation but Preserves Annular and Leaflet Dynamics

Ischemic Mitral Regurgitation on the Threshold of a Solution

Pregnancy-induced remodeling of heart valves

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