Elimination of Moderate Ischemic MR does not Ameliorate Long-Term LV Remodeling
Kanji Matsusaki, Mio Noma, Aaron S. Blom, Thomas J. Eperjesi, Liam P. Ryan, Theodore Plappert, Martin G. St. John-Sutton, Joseph H. Gorman, Robert C. Gorman; Surgery, University of Pennsylvania, Philadelphia, PA
Comment on this Abstract
Objective: The efficacy of mitral valve repair for ischemic mitral regurgitation (IMR) has been difficult to demonstrate clinically. Clinical studies are confounded by lack of randomization, concomitant coronary revascularization and variability in repair/replacement techniques. Using a well established ovine model of IMR we tested the ability of rigid, complete, undersized annuloplasty to durably relieve established IMR as well as its effect on global LV remodeling during a clinically relevant follow-up period (6 months).
Methods: Twenty-three sheep were subjected to a posterolateral infarction of 20 to 25% of the LV mass that is known to result in chronic IMR. Animals were studied with 3D echocardiography to assess LV size before infarction. Three sheep died between 1 and 14 days post infarction. Twenty sheep survived to 8weeks after infarction. Fourteen of these animals underwent placement of a 26mm rigid, complete annuloplasty using standard surgical techniques. Six animals were untreated controls. The degree of IMR (0 to 4 scale) was assessed at the time of annuloplasty placement using 2D color flow Doppler echocardiography. LV remodeling and degree of IMR were assessed 6 months after surgery using 3D echocardiography. End systolic (ESV) and end diastolic (EDV) volumes were used to assess global remodeling.
Results: All animals had similarly sized hearts at baseline (ESV=27.6±1.4ml; EDV=53.7±2.5ml).All 20 animals that survived to 8 weeks completed the study. The degree of IMR at 8 weeks was similar in both groups (treatment= 2.3±0.3; Control 2.1±0.3). At the six month follow-up the degree of IMR was significantly less in the treatment group (0.4±0.4 vs. 2.9±0.6); however, the LV volumes in the treatment group (ESV=79.9±5.7ml; EDV=107.7±7.9) were not significantly different from the control group (ESV=87.9±10.7ml; EDV=119.3±9.9).
Conclusion: Rigid, complete, undersized annuloplasty provides durable relief from IMR over a clinically relevant follow-up period but does not significantly influence LV remodeling. These conclusions may be invalid for more severe degrees of IMR.
Back to 88th Annual Meeting
Back to Program Outline
