AI Article Synopsis
- The study examines the effects of posterior papillary muscle anchoring (PPMA) on left ventricular stress and pump function in cases of chronic ischemic mitral regurgitation (CIMR) following myocardial infarction in sheep.
- Different anchoring techniques and relocation displacements were tested, revealing that PPMA consistently reduced myofiber stress in the heart, especially in the affected areas, without significantly compromising overall pump function.
- Results suggest that using PPMA to manage stress in the myocardium may help improve heart remodeling without negatively impacting left ventricular performance, regardless of the anchoring point chosen.
Article Abstract
Background: The role of posterior papillary muscle anchoring (PPMA) in the management of chronic ischemic mitral regurgitation (CIMR) is controversial. We studied the effect of anchoring point direction and relocation displacement on left ventricular (LV) regional myofiber stress and pump function.
Methods: Previously described finite element models of sheep 16 weeks after posterolateral myocardial infarction (MI) were used. True-sized mitral annuloplasty (MA) ring insertion plus different PPM anchoring techniques were simulated. Anchoring points tested included both commissures and the central anterior mitral annulus; relocation displacement varied from 10% to 40% of baseline diastolic distance from the PPM to the anchor points on the annulus. For each reconstruction scenario, myofiber stress in the MI, border zone, and remote myocardium as well as pump function were calculated.
Results: PPMA caused reductions in myofiber stress at end-diastole and end-systole in all regions of the left ventricle that were proportional to the relocation displacement. Although stress reduction was greatest in the MI region, it also occurred in the remote region. The maximum 40% displacement caused a slight reduction in LV pump function. However, with the correction of regurgitation by MA plus PPMA, there was an overall increase in forward stroke volume. Finally, anchoring point direction had no effect on myofiber stress or pump function.
Conclusions: PPMA reduces remote myofiber stress, which is proportional to the absolute distance of relocation and independent of anchoring point. Aggressive use of PPMA techniques to reduce remote myofiber stress may accelerate reverse LV remodeling without impairing LV function.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051352 | PMC |
| http://dx.doi.org/10.1016/j.athoracsur.2014.04.077 | DOI Listing |
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