BACKGROUND AND AIM OF THE STUDY: Improved knowledge of mitral valve (MV) mechanics is essential to understand normal MV function and design and evaluate new surgical repair procedures. Initially, the dynamic deformation of the central region of the porcine MV anterior leaflet was quantified under simulated physiological conditions to explore the effects of varying papillary muscle (PM) position. METHODS: Fresh porcine MVs were mounted in an in-vitro physiological flow loop. The PM positions were set to normal, taut, and slack states to simulate physiological and pathological PM positions. Leaflet deformation was measured by tracking the displacement of 16 markers (approximately 250 microm diameter) placed in a 5 x 5 mm section of the central region of the anterior leaflet, approximately 5 mm from the annulus and coaptation line. Local leaflet tissue strain and strain rates were calculated from measured displacements under dynamic loading conditions. A total of 11 mitral valves was studied. RESULTS: Under the normal PM positional state, the average areal strain rate during valve closure was typically approximately 620% per second. While not measurably altering the maximal areal strain rate, the slack PM position led to a delay in complete valve closure and more rapid leaflet loading (defined as delta transvalvular pressure/delta areal strain) in late systole compared to the other two PM positions. CONCLUSION: It was shown that PM position influenced the MV loading process in the central area of the anterior leaflet. The slack PM position led to a delay in complete valve closure and more rapid leaflet loading in late systole. This increase in loading rate may have long-term consequences in MV function.
BACKGROUND AND AIM OF THE STUDY: Improved knowledge of mitral valve (MV) mechanics is essential to understand normal MV function and design and evaluate new surgical repair procedures. Initially, the dynamic deformation of the central region of the porcine MV anterior leaflet was quantified under simulated physiological conditions to explore the effects of varying papillary muscle (PM) position. METHODS: Fresh porcine MVs were mounted in an in-vitro physiological flow loop. The PM positions were set to normal, taut, and slack states to simulate physiological and pathological PM positions. Leaflet deformation was measured by tracking the displacement of 16 markers (approximately 250 microm diameter) placed in a 5 x 5 mm section of the central region of the anterior leaflet, approximately 5 mm from the annulus and coaptation line. Local leaflet tissue strain and strain rates were calculated from measured displacements under dynamic loading conditions. A total of 11 mitral valves was studied. RESULTS: Under the normal PM positional state, the average areal strain rate during valve closure was typically approximately 620% per second. While not measurably altering the maximal areal strain rate, the slack PM position led to a delay in complete valve closure and more rapid leaflet loading (defined as delta transvalvular pressure/delta areal strain) in late systole compared to the other two PM positions. CONCLUSION: It was shown that PM position influenced the MV loading process in the central area of the anterior leaflet. The slack PM position led to a delay in complete valve closure and more rapid leaflet loading in late systole. This increase in loading rate may have long-term consequences in MV function.
Authors: Gaurav Krishnamurthy; Daniel B Ennis; Akinobu Itoh; Wolfgang Bothe; Julia C Swanson; Matts Karlsson; Ellen Kuhl; D Craig Miller; Neil B Ingels Journal: Am J Physiol Heart Circ Physiol Date: 2008-07-11 Impact factor: 4.733
Authors: Annabel M Imbrie-Moore; Matthew H Park; Michael J Paulsen; Mark Sellke; Rohun Kulkami; Hanjay Wang; Yuanjia Zhu; Justin M Farry; Alexandra T Bourdillon; Christine Callinan; Haley J Lucian; Camille E Hironaka; Daniela Deschamps; Y Joseph Woo Journal: J R Soc Interface Date: 2020-12-02 Impact factor: 4.118
Authors: Salma Ayoub; Giovanni Ferrari; Robert C Gorman; Joseph H Gorman; Frederick J Schoen; Michael S Sacks Journal: Compr Physiol Date: 2016-09-15 Impact factor: 9.090
Authors: Wolfgang Bothe; Ellen Kuhl; John-Peder Escobar Kvitting; Manuel K Rausch; Serdar Göktepe; Julia C Swanson; Saideh Farahmandnia; Neil B Ingels; D Craig Miller Journal: Circulation Date: 2011-09-13 Impact factor: 29.690
Authors: Charles H Bloodworth; Eric L Pierce; Thomas F Easley; Andrew Drach; Amir H Khalighi; Milan Toma; Morten O Jensen; Michael S Sacks; Ajit P Yoganathan Journal: Ann Biomed Eng Date: 2016-10-03 Impact factor: 3.934
Authors: Gaurav Krishnamurthy; Akinobu Itoh; Wolfgang Bothe; Julia C Swanson; Ellen Kuhl; Matts Karlsson; D Craig Miller; Neil B Ingels Journal: J Biomech Date: 2009-06-16 Impact factor: 2.712