Background: The ratio of LV end-systolic dimension (LVESd)/mitral valve (MV) ring size (LV-MV Ring Mismatch) has been shown to be associated with recurrent ischemic mitral regurgitation (IMR) after restrictive annuloplasty. We aimed to examine the effect of MV repair on MV tethering and correlate changes in MV tethering to degree of LV-MV mismatch, hypothesizing that persistent posterior leaflet tethering post annuloplasty is the underlying mechanism for the association between LVESd/MV ring ratio and recurrent IMR.
Methods: Patients from two Cardiothoracic Surgical Trials Network (CTSN) IMR trials who underwent ring annuloplasty with complete echo data and with appropriate image quality for quantification at 1 yr post annuloplasty were eligible (154 out of 276 patients) MV tethering geometry (tenting height and area, and posterior/anterior leaflet angles) were measured at baseline and 1 year post annuloplasty. LVESd/MV ring ratio was sub grouped into quartiles.
Results: Restrictive annuloplasty was associated with reduced global tethering (tenting height: 10±3 to 8±3 mm, p<0.05; tenting area: 2.2±0.9 to 1.4±0.7 cm2, p<0.05) but increased posterior leaflet tethering (posterior angle: 50±10 to 56±14°, p<0.05) (FigA). Patients in 4th quartile of LVESd/MV ring ratio had highest baseline and post-operative MV tethering (FigA). Posterior leaflet angle was higher in the 4th quartile of LVESd/MV ring size ratio compared to other quartiles both at baseline and at 1 year (FigA). LVESd/MV ring ratio was associated with larger posterior leaflet angle post annuloplasty (p<0.02).
Conclusion: Restrictive annuloplasty for IMR is associated with reduced global MV tethering but increased posterior leaflet tethering. LVESd/MV ring ratio is associated with MV tethering at baseline as well as persistent/increased posterior leaflet tethering at 1 year post annuloplasty, identifying a potential underlying mechanism of recurrent IMR (FigB).