Stress Sharing Between the Sinus and Leaflets of Canine Aortic Valve

Thubrikar, Mano J.; Nolan, Stanton P.; Aouad, Jaafar; Deck, J. David

doi:10.1016/s0003-4975(10)60554-1

Cited by 110 publications

(61 citation statements)

References 15 publications

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“…36,37 Theories of cardiac valve calcification have implicated abnormal blood flow rheology, which results in abnormal mechanical stress and valvular damage. 38 Further work is necessary to better understand the interaction between biophysical and molecular factors that promote microfractures, trigger fracture healing, stimulate heterotopic ossification, and regulate remodeling in damaged heart valves.…”

Section: Discussionmentioning

confidence: 99%

Bone Formation and Inflammation in Cardiac Valves

et al. 2001

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Background-For nearly a century, the mechanical failure of calcified heart valves was attributed to a passive degenerative process. Recently, several case reports described bone formation in surgically excised heart valves and suggested an unexpected process of tissue repair. Methods and Results-We studied the prevalence and pathology of heterotopic ossification in 347 surgically excised heart valves (256 aortic, 91 mitral) in 324 consecutive patients (182 men, 142 women; mean age 68 years) who underwent cardiac valve replacement surgery between 1994 and 1998. The valves were examined microscopically to determine the prevalence and features of bone formation and remodeling. Two hundred eighty-eight valves (83%) had dystrophic calcification. Mature lamellar bone with hematopoietic elements and active bone remodeling were present in 36 valves (13%) with dystrophic calcification. Endochondral bone formation, similar to that seen in normal fracture repair, was identified in 4 valves. Microfractures were present in 92% of all valves with ossification. Neoangiogenesis was found in all valves with ossification. Bone morphogenetic proteins 2 and 4 (BMP 2/4), potent osteogenic morphogens, were expressed by myofibroblasts and preosteoblasts in areas adjacent to B-and T-lymphocyte infiltration in valves where ossification was identified. Mast cells were present in calcified and ossified valves and were especially prominent in atheromatous regions. Conclusions-Heterotopic

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Section: Discussionmentioning

confidence: 99%

Bone Formation and Inflammation in Cardiac Valves

et al. 2001

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“…Physiologically, the valve experiences 10 -12% stretch in the circumferential direction (33). Beyond 15-17%, the collagen fibers are fully stretched and "locked up" (17,37). Therefore, at 20%, there is a possibility of damage to collagen fibers and the attached interstitial cells (3,4).…”

Section: Discussionmentioning

confidence: 99%

“…However, the response of aortic valve tissue or cells to cyclic stretch has not been very extensively studied. Cyclic stretch is one of the forces experienced by the aortic valve during the cardiac cycle that allows the valve cusps to extend and form a coaptive seal with each other during diastole (33,36,37). The valve, under normal physiological conditions, experiences ϳ10% stretch during diastole (17,32).…”

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confidence: 99%

Elevated cyclic stretch alters matrix remodeling in aortic valve cusps: implications for degenerative aortic valve disease

Balachandran

Sucosky²,

Jo³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

174

147

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Matrix metalloproteinases (MMPs) and cathepsins are proteolytic enzymes that are upregulated in diseased aortic valve cusps. The objective of this study was to investigate whether elevated cyclic stretch causes an increased expression and activity of these proteolytic enzymes in the valve cusp. Circumferentially oriented fresh porcine aortic valve cusp sections were stretched to 10% (physiological), 15% (pathological), and 20% (hyperpathological) in a tensile stretch bioreactor for 24 and 48 h. The expression and activity of MMP-1, MMP-2, MMP-9, tissue inhibitor of MMP-1, and cathepsin L, S, and K were quantified and compared with fresh controls. Cell proliferation and apoptosis were also analyzed. As a result, at 10% physiological stretch, the expression and activity of remodeling enzymes were comparable with fresh controls. At 15% stretch, the expression of MMP-1, -2, -9 and cathepsin S and K were upregulated, whereas the expression of cathepsin L was downregulated compared with controls. A similar trend was observed at 20% stretch, but the magnitudes of upregulation and downregulation of the expression were less than those observed at 15%. In addition, there were significantly higher cell proliferation and apoptosis at 20% stretch compared with those of other treatment groups. In conclusion, elevated mechanical stretch on aortic valve cusps may detrimentally alter the proteolytic enzyme expression and activity in valve cells. This may trigger a cascade of events leading to an accelerated valve degeneration and disease progression.

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“…27 for the surface area > 1.9 m 2 [3]. Aortic annulus diameter decreases by 16% from systole to diastole [15] [20]. In our study, we considered the decrease of annulus diameter at the diastole and therefore, AVR was performed during the diastolic arrest, where the annulus was decreased by 16%.…”

Section: Discussionmentioning

confidence: 99%

Surgical Method for Facilitation of Aortic Valve Replacement: Intraoperative Application of External Pressure for Increasing the Transverse Axis of Aortic Annulus

Bozok¹,

Kestelli²,

Şahin³

et al. 2015

WJCS

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Background: Surgical method was introduced for enhancement of prosthetic valve insertion and overcoming difficulties ensourcing from prosthesis-patient mismatch. Methods: Twenty-two patients that underwent aortic valve replacement between January 2005 and July 2009 were included in this prospective study. In these patients, the insertion of prosthesis larger than the annulus diameter was attempted after the application of an external pressure that increased the transverse axis diameter of the aortic annulus. The postoperative results and complications were assessed. Results: This surgical method was performed on 22 patients (16 males, 6 females, mean age: 52.2 ± 15.8 years) during the valve replacement. In 12 patients (55%), replacement of proper sized aortic valve compliant to their surface area was accomplished, while the insertion of a proper valve could not be achieved in 10 (45%) of the patients. No perioperative mortality or complications related to the procedure were reported. Conclusion: Increasing the transverse diameter of aortic valve may not only facilitate the insertion of a prosthetic valve but also aid in overcoming * Corresponding author. Ş. Bozok et al. 109prosthesis-patient mismatch. Further studies on larger series are necessary to document the actual effectively and precise selection criteria for application of this method.

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Stress Sharing Between the Sinus and Leaflets of Canine Aortic Valve

Cited by 110 publications

References 15 publications

Bone Formation and Inflammation in Cardiac Valves

Bone Formation and Inflammation in Cardiac Valves

Elevated cyclic stretch alters matrix remodeling in aortic valve cusps: implications for degenerative aortic valve disease

Surgical Method for Facilitation of Aortic Valve Replacement: Intraoperative Application of External Pressure for Increasing the Transverse Axis of Aortic Annulus

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