Papillary muscle misalignment causes multiple mitral regurgitant jets

An ambiguous mechanism for functional mitral regurgitation

Sten L. Nielsen, Hans Nygaard, Arnold Anthony Fontaine, J. Michael Hasenkam, Shengqui He, Ajit P. Yoganathan

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Background and aims of the study: The study aim was to test the hypothesis that asymmetric alignment (misalignment) of the papillary muscles is sufficient to cause incomplete mitral leaflet coaptation and functional mitral regurgitation (MR). Methods: Different spatial relationships between the papillary muscles and the mitral annulus were investigated in isolated porcine mitral valves in vitro to assess the impact on mitral valve competence. The systolic occlusional leaflet area (OLA) needed to cover the mitral orifice and the anterolateral (ACOM) and posteromedial (PCOM) commissural portion (OLA(ACOM), OLA(PCOM)) were assessed by 2D echocardiography to quantitate incomplete mitral leaflet coaptation. The regurgitant fraction (RF) and MR jet location were assessed by a flow meter and color Doppler ultrasound. Results: Posterolateral dislocation of the posteromedial papillary muscle impaired mitral leaflet coaptation at the corresponding half-portion of the mitral orifice (OLA(PCOM): 351-397 mm 2 versus 296 mm 2 (normal); p < 0.001) and modified the contralateral part (OLA(ACOM): 354-387 mm 2 versus 304 mm 2 (normal); p <0.001). The mitral leaflet coaptation line moved in apical and posterior directions, creating a commissural MR orifice at the PCOM side. At the ACOM side, anterior leaflet prolapse and restricted posterior leaflet mobility created an additional commissural regurgitant jet (RF = 0.11-0.13). Symmetrical papillary muscle misalignment restricted mitral leaflet mobility on both sides of the orifice in a synergistic manner (OLA(PCOM): 416-459 mm 2 and OLA(ACOM): 427-489 mm 2 ; both p <0.001 versus normal). The central MR jet orifice, which extended towards both commissures, caused more significant MR (RF = 0.15-0.26). Conclusions: Papillary muscle misalignment caused mitral regurgitant jet ambiguity with an anterior MR jet location following posteromedial papillary muscle displacement. These findings may improve understanding of the relation between myocardial lesion and mitral regurgitant jet location and thereby facilitate rational strategies for valvular interventions.

Original languageEnglish (US)
Pages (from-to)551-564
Number of pages14
JournalJournal of Heart Valve Disease
Volume8
Issue number5
StatePublished - Sep 1 1999

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Papillary Muscles
Mitral Valve Insufficiency
Mitral Valve
Doppler Ultrasonography
Prolapse
Mental Competency
Echocardiography
Swine
Color

All Science Journal Classification (ASJC) codes

  • Medicine(all)

Cite this

Nielsen, Sten L. ; Nygaard, Hans ; Fontaine, Arnold Anthony ; Hasenkam, J. Michael ; He, Shengqui ; Yoganathan, Ajit P. / Papillary muscle misalignment causes multiple mitral regurgitant jets : An ambiguous mechanism for functional mitral regurgitation. In: Journal of Heart Valve Disease. 1999 ; Vol. 8, No. 5. pp. 551-564.
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title = "Papillary muscle misalignment causes multiple mitral regurgitant jets: An ambiguous mechanism for functional mitral regurgitation",
abstract = "Background and aims of the study: The study aim was to test the hypothesis that asymmetric alignment (misalignment) of the papillary muscles is sufficient to cause incomplete mitral leaflet coaptation and functional mitral regurgitation (MR). Methods: Different spatial relationships between the papillary muscles and the mitral annulus were investigated in isolated porcine mitral valves in vitro to assess the impact on mitral valve competence. The systolic occlusional leaflet area (OLA) needed to cover the mitral orifice and the anterolateral (ACOM) and posteromedial (PCOM) commissural portion (OLA(ACOM), OLA(PCOM)) were assessed by 2D echocardiography to quantitate incomplete mitral leaflet coaptation. The regurgitant fraction (RF) and MR jet location were assessed by a flow meter and color Doppler ultrasound. Results: Posterolateral dislocation of the posteromedial papillary muscle impaired mitral leaflet coaptation at the corresponding half-portion of the mitral orifice (OLA(PCOM): 351-397 mm 2 versus 296 mm 2 (normal); p < 0.001) and modified the contralateral part (OLA(ACOM): 354-387 mm 2 versus 304 mm 2 (normal); p <0.001). The mitral leaflet coaptation line moved in apical and posterior directions, creating a commissural MR orifice at the PCOM side. At the ACOM side, anterior leaflet prolapse and restricted posterior leaflet mobility created an additional commissural regurgitant jet (RF = 0.11-0.13). Symmetrical papillary muscle misalignment restricted mitral leaflet mobility on both sides of the orifice in a synergistic manner (OLA(PCOM): 416-459 mm 2 and OLA(ACOM): 427-489 mm 2 ; both p <0.001 versus normal). The central MR jet orifice, which extended towards both commissures, caused more significant MR (RF = 0.15-0.26). Conclusions: Papillary muscle misalignment caused mitral regurgitant jet ambiguity with an anterior MR jet location following posteromedial papillary muscle displacement. These findings may improve understanding of the relation between myocardial lesion and mitral regurgitant jet location and thereby facilitate rational strategies for valvular interventions.",
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Papillary muscle misalignment causes multiple mitral regurgitant jets : An ambiguous mechanism for functional mitral regurgitation. / Nielsen, Sten L.; Nygaard, Hans; Fontaine, Arnold Anthony; Hasenkam, J. Michael; He, Shengqui; Yoganathan, Ajit P.

In: Journal of Heart Valve Disease, Vol. 8, No. 5, 01.09.1999, p. 551-564.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Papillary muscle misalignment causes multiple mitral regurgitant jets

T2 - An ambiguous mechanism for functional mitral regurgitation

AU - Nielsen, Sten L.

AU - Nygaard, Hans

AU - Fontaine, Arnold Anthony

AU - Hasenkam, J. Michael

AU - He, Shengqui

AU - Yoganathan, Ajit P.

PY - 1999/9/1

Y1 - 1999/9/1

N2 - Background and aims of the study: The study aim was to test the hypothesis that asymmetric alignment (misalignment) of the papillary muscles is sufficient to cause incomplete mitral leaflet coaptation and functional mitral regurgitation (MR). Methods: Different spatial relationships between the papillary muscles and the mitral annulus were investigated in isolated porcine mitral valves in vitro to assess the impact on mitral valve competence. The systolic occlusional leaflet area (OLA) needed to cover the mitral orifice and the anterolateral (ACOM) and posteromedial (PCOM) commissural portion (OLA(ACOM), OLA(PCOM)) were assessed by 2D echocardiography to quantitate incomplete mitral leaflet coaptation. The regurgitant fraction (RF) and MR jet location were assessed by a flow meter and color Doppler ultrasound. Results: Posterolateral dislocation of the posteromedial papillary muscle impaired mitral leaflet coaptation at the corresponding half-portion of the mitral orifice (OLA(PCOM): 351-397 mm 2 versus 296 mm 2 (normal); p < 0.001) and modified the contralateral part (OLA(ACOM): 354-387 mm 2 versus 304 mm 2 (normal); p <0.001). The mitral leaflet coaptation line moved in apical and posterior directions, creating a commissural MR orifice at the PCOM side. At the ACOM side, anterior leaflet prolapse and restricted posterior leaflet mobility created an additional commissural regurgitant jet (RF = 0.11-0.13). Symmetrical papillary muscle misalignment restricted mitral leaflet mobility on both sides of the orifice in a synergistic manner (OLA(PCOM): 416-459 mm 2 and OLA(ACOM): 427-489 mm 2 ; both p <0.001 versus normal). The central MR jet orifice, which extended towards both commissures, caused more significant MR (RF = 0.15-0.26). Conclusions: Papillary muscle misalignment caused mitral regurgitant jet ambiguity with an anterior MR jet location following posteromedial papillary muscle displacement. These findings may improve understanding of the relation between myocardial lesion and mitral regurgitant jet location and thereby facilitate rational strategies for valvular interventions.

AB - Background and aims of the study: The study aim was to test the hypothesis that asymmetric alignment (misalignment) of the papillary muscles is sufficient to cause incomplete mitral leaflet coaptation and functional mitral regurgitation (MR). Methods: Different spatial relationships between the papillary muscles and the mitral annulus were investigated in isolated porcine mitral valves in vitro to assess the impact on mitral valve competence. The systolic occlusional leaflet area (OLA) needed to cover the mitral orifice and the anterolateral (ACOM) and posteromedial (PCOM) commissural portion (OLA(ACOM), OLA(PCOM)) were assessed by 2D echocardiography to quantitate incomplete mitral leaflet coaptation. The regurgitant fraction (RF) and MR jet location were assessed by a flow meter and color Doppler ultrasound. Results: Posterolateral dislocation of the posteromedial papillary muscle impaired mitral leaflet coaptation at the corresponding half-portion of the mitral orifice (OLA(PCOM): 351-397 mm 2 versus 296 mm 2 (normal); p < 0.001) and modified the contralateral part (OLA(ACOM): 354-387 mm 2 versus 304 mm 2 (normal); p <0.001). The mitral leaflet coaptation line moved in apical and posterior directions, creating a commissural MR orifice at the PCOM side. At the ACOM side, anterior leaflet prolapse and restricted posterior leaflet mobility created an additional commissural regurgitant jet (RF = 0.11-0.13). Symmetrical papillary muscle misalignment restricted mitral leaflet mobility on both sides of the orifice in a synergistic manner (OLA(PCOM): 416-459 mm 2 and OLA(ACOM): 427-489 mm 2 ; both p <0.001 versus normal). The central MR jet orifice, which extended towards both commissures, caused more significant MR (RF = 0.15-0.26). Conclusions: Papillary muscle misalignment caused mitral regurgitant jet ambiguity with an anterior MR jet location following posteromedial papillary muscle displacement. These findings may improve understanding of the relation between myocardial lesion and mitral regurgitant jet location and thereby facilitate rational strategies for valvular interventions.

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