Effects of Annular Size, Transmitral Pressure, and Mitral Flow Rate on the Edge-To-Edge Repair: An In Vitro Study

Jorge H. Jimenez, Joseph Forbess, Laura R. Croft, Lisa Small, Zhaoming He, Ajit P. Yoganathan

Research output: Contribution to journalArticle

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Abstract

Background: Although edge-to-edge repair is an established adjunctive procedure, there is still debate on its long-term durability and efficacy. Methods: Fifteen porcine mitral valves were studied in a physiologic left heart simulator with a variable size annulus (dilated = 8.22 cm2, normal = 6.86 cm2, contracted = 5.5 cm2). Mitral valves were tested under steady and physiologic pulsatile flow conditions (cardiac outputs: 4 to 6 L/min), at peak transmitral pressures between 100 mm Hg and 140 mm Hg. A miniature force transducer was used to measure the Alfieri stitch force (FA). Mitral flow rate (MFR), transmitral pressure, effective orifice area, mitral regurgitation, and FA were monitored. Results: The edge-to-edge repair led to a decrease in effective orifice area of 16.55% ± 8.22%; further reduction in effective orifice area was attained with annular contraction. Mitral regurgitation after the edge-to-edge repair was significantly higher (p <0.05) with annular dilation. In the pulsatile experiments, two peaks in FA were observed: one during systole (FA = 0.059 ± 0.024 N) and a second during diastole (FA = 0.072 ± 0.021 N). Multivariate analysis of variance analysis showed that during systole, transmitral pressure and mitral annular area (MAA) had significant effects on FA [FA = (4.40 × 10-4) transmitral pressure (mm Hg) + (5.0 × 10-3) MAA (cm2) - 0.05 (R2= 0.80)], whereas during diastole MFR and MAA had significant effects on FA [FA = (1.03 × 10-4) MFR2 (L/min) - (1.60 × 10-3) MAA (cm2) + 0.02 (R2 = 0.90)]. Conclusions: With annular dilation, mitral regurgitation persisted even after the edge-to-edge repair. The edge-to-edge repair does not cause clinically relevant mitral valve stenosis in a normal size mitral valve. Mitral flow rate and transmitral pressure are the main determinants of FA during the cardiac cycle. Increasing annular area increases FA during systole but decreases FA during diastole. Systolic FA may become dominant with increases in MAA or peak transmitral pressure, or both.

Original languageEnglish (US)
Pages (from-to)1362-1368
Number of pages7
JournalAnnals of Thoracic Surgery
Volume82
Issue number4
DOIs
StatePublished - Oct 2006

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Pressure
Diastole
Systole
Mitral Valve Insufficiency
Mitral Valve
Dilatation
Analysis of Variance
Pulsatile Flow
Mitral Valve Stenosis
Transducers
Cardiac Output
In Vitro Techniques
Swine
Multivariate Analysis

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Surgery

Cite this

Effects of Annular Size, Transmitral Pressure, and Mitral Flow Rate on the Edge-To-Edge Repair : An In Vitro Study. / Jimenez, Jorge H.; Forbess, Joseph; Croft, Laura R.; Small, Lisa; He, Zhaoming; Yoganathan, Ajit P.

In: Annals of Thoracic Surgery, Vol. 82, No. 4, 10.2006, p. 1362-1368.

Research output: Contribution to journalArticle

Jimenez, Jorge H. ; Forbess, Joseph ; Croft, Laura R. ; Small, Lisa ; He, Zhaoming ; Yoganathan, Ajit P. / Effects of Annular Size, Transmitral Pressure, and Mitral Flow Rate on the Edge-To-Edge Repair : An In Vitro Study. In: Annals of Thoracic Surgery. 2006 ; Vol. 82, No. 4. pp. 1362-1368.
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abstract = "Background: Although edge-to-edge repair is an established adjunctive procedure, there is still debate on its long-term durability and efficacy. Methods: Fifteen porcine mitral valves were studied in a physiologic left heart simulator with a variable size annulus (dilated = 8.22 cm2, normal = 6.86 cm2, contracted = 5.5 cm2). Mitral valves were tested under steady and physiologic pulsatile flow conditions (cardiac outputs: 4 to 6 L/min), at peak transmitral pressures between 100 mm Hg and 140 mm Hg. A miniature force transducer was used to measure the Alfieri stitch force (FA). Mitral flow rate (MFR), transmitral pressure, effective orifice area, mitral regurgitation, and FA were monitored. Results: The edge-to-edge repair led to a decrease in effective orifice area of 16.55{\%} ± 8.22{\%}; further reduction in effective orifice area was attained with annular contraction. Mitral regurgitation after the edge-to-edge repair was significantly higher (p <0.05) with annular dilation. In the pulsatile experiments, two peaks in FA were observed: one during systole (FA = 0.059 ± 0.024 N) and a second during diastole (FA = 0.072 ± 0.021 N). Multivariate analysis of variance analysis showed that during systole, transmitral pressure and mitral annular area (MAA) had significant effects on FA [FA = (4.40 × 10-4) transmitral pressure (mm Hg) + (5.0 × 10-3) MAA (cm2) - 0.05 (R2= 0.80)], whereas during diastole MFR and MAA had significant effects on FA [FA = (1.03 × 10-4) MFR2 (L/min) - (1.60 × 10-3) MAA (cm2) + 0.02 (R2 = 0.90)]. Conclusions: With annular dilation, mitral regurgitation persisted even after the edge-to-edge repair. The edge-to-edge repair does not cause clinically relevant mitral valve stenosis in a normal size mitral valve. Mitral flow rate and transmitral pressure are the main determinants of FA during the cardiac cycle. Increasing annular area increases FA during systole but decreases FA during diastole. Systolic FA may become dominant with increases in MAA or peak transmitral pressure, or both.",
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T1 - Effects of Annular Size, Transmitral Pressure, and Mitral Flow Rate on the Edge-To-Edge Repair

T2 - An In Vitro Study

AU - Jimenez, Jorge H.

AU - Forbess, Joseph

AU - Croft, Laura R.

AU - Small, Lisa

AU - He, Zhaoming

AU - Yoganathan, Ajit P.

PY - 2006/10

Y1 - 2006/10

N2 - Background: Although edge-to-edge repair is an established adjunctive procedure, there is still debate on its long-term durability and efficacy. Methods: Fifteen porcine mitral valves were studied in a physiologic left heart simulator with a variable size annulus (dilated = 8.22 cm2, normal = 6.86 cm2, contracted = 5.5 cm2). Mitral valves were tested under steady and physiologic pulsatile flow conditions (cardiac outputs: 4 to 6 L/min), at peak transmitral pressures between 100 mm Hg and 140 mm Hg. A miniature force transducer was used to measure the Alfieri stitch force (FA). Mitral flow rate (MFR), transmitral pressure, effective orifice area, mitral regurgitation, and FA were monitored. Results: The edge-to-edge repair led to a decrease in effective orifice area of 16.55% ± 8.22%; further reduction in effective orifice area was attained with annular contraction. Mitral regurgitation after the edge-to-edge repair was significantly higher (p <0.05) with annular dilation. In the pulsatile experiments, two peaks in FA were observed: one during systole (FA = 0.059 ± 0.024 N) and a second during diastole (FA = 0.072 ± 0.021 N). Multivariate analysis of variance analysis showed that during systole, transmitral pressure and mitral annular area (MAA) had significant effects on FA [FA = (4.40 × 10-4) transmitral pressure (mm Hg) + (5.0 × 10-3) MAA (cm2) - 0.05 (R2= 0.80)], whereas during diastole MFR and MAA had significant effects on FA [FA = (1.03 × 10-4) MFR2 (L/min) - (1.60 × 10-3) MAA (cm2) + 0.02 (R2 = 0.90)]. Conclusions: With annular dilation, mitral regurgitation persisted even after the edge-to-edge repair. The edge-to-edge repair does not cause clinically relevant mitral valve stenosis in a normal size mitral valve. Mitral flow rate and transmitral pressure are the main determinants of FA during the cardiac cycle. Increasing annular area increases FA during systole but decreases FA during diastole. Systolic FA may become dominant with increases in MAA or peak transmitral pressure, or both.

AB - Background: Although edge-to-edge repair is an established adjunctive procedure, there is still debate on its long-term durability and efficacy. Methods: Fifteen porcine mitral valves were studied in a physiologic left heart simulator with a variable size annulus (dilated = 8.22 cm2, normal = 6.86 cm2, contracted = 5.5 cm2). Mitral valves were tested under steady and physiologic pulsatile flow conditions (cardiac outputs: 4 to 6 L/min), at peak transmitral pressures between 100 mm Hg and 140 mm Hg. A miniature force transducer was used to measure the Alfieri stitch force (FA). Mitral flow rate (MFR), transmitral pressure, effective orifice area, mitral regurgitation, and FA were monitored. Results: The edge-to-edge repair led to a decrease in effective orifice area of 16.55% ± 8.22%; further reduction in effective orifice area was attained with annular contraction. Mitral regurgitation after the edge-to-edge repair was significantly higher (p <0.05) with annular dilation. In the pulsatile experiments, two peaks in FA were observed: one during systole (FA = 0.059 ± 0.024 N) and a second during diastole (FA = 0.072 ± 0.021 N). Multivariate analysis of variance analysis showed that during systole, transmitral pressure and mitral annular area (MAA) had significant effects on FA [FA = (4.40 × 10-4) transmitral pressure (mm Hg) + (5.0 × 10-3) MAA (cm2) - 0.05 (R2= 0.80)], whereas during diastole MFR and MAA had significant effects on FA [FA = (1.03 × 10-4) MFR2 (L/min) - (1.60 × 10-3) MAA (cm2) + 0.02 (R2 = 0.90)]. Conclusions: With annular dilation, mitral regurgitation persisted even after the edge-to-edge repair. The edge-to-edge repair does not cause clinically relevant mitral valve stenosis in a normal size mitral valve. Mitral flow rate and transmitral pressure are the main determinants of FA during the cardiac cycle. Increasing annular area increases FA during systole but decreases FA during diastole. Systolic FA may become dominant with increases in MAA or peak transmitral pressure, or both.

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