Letter by Pocar Regarding Article, “Impact of Left Ventricular to Mitral Valve Ring Mismatch on Recurrent Ischemic Mitral Regurgitation After Ring Annuloplasty”
Authors: Marco Pocar
Journal: Circulation (2017)

Capoulade et al 1 should be commended for outlining the interesting correlation between left ventricular end-systolic dimension to mitral valve ring size ratio (LVESd/ MV) and recurrent ischemic mitral regurgitation (MR) after annuloplasty.The authors, however, do not suggest a preoperative LVESd/MV cutoff to predict an unsuccessful repair.Considering the observed 30% MR recurrence, it could be assumed that the 4th quartile may represent patients more likely to have an unsuccessful repair.This implies that an LVESd/MV ˃2 could possibly indicate the limit for not performing annuloplasty alone.However, MR recurrence ≥2+ rates as low as 15% at 4.3 years have been reported with more aggressive undersizing to determine a minimum coaptation height of 8 mm. 2 This finding is opposite to the authors' hypothesis because a smaller ring determines a higher LVESd/MV and, theoretically, a less favorable outcome.Implanted ring size was near uniform throughout the population, averaging 28 mm in all quartiles, whereas LV dimensions where significantly different, which implies that a somewhat standard operation was performed regardless of baseline LV remodeling.Not surprisingly, this simply suggests that the larger the ventricle, the higher the probability of late MR recurrence if ring undersizing is not tailored to the patient.In fact, LVESd measured at the tip of the MV leaflets, and thus at a plane dependent on coaptation depth and severity of mitral tethering, reflects the degree of localized LV remodeling in the basal segments.Preoperative LVESd only reached a trend toward significance to predict MR recurrence at multivariable analysis (P=0.07), possibly as an effect of sample size.However, it could be speculated that early postoperative LVESd could more accurately predict outcome because MR correction acutely determines global LV reverse remodeling, 3 and LVESd is thus reduced in the case of viable myocardium.Consequently, the surgeon should ideally focus on the probability of basal reverse remodeling to achieve a durable repair.This correlates with previously outlined predictors of MR recurrence, focused on inferoposterior tethering, including posterior leaflet angle or inferoposterior regional wall motion. 3oreover, ring size defined as the commercially available size is misleading because actual sizes may vary according to different models.For instance, similar A2-P2 stabilizing distances can be obtained with a Carpentier Physio n. 26 (Edwards Lifesciences) or Sorin Memo 3D n. 28 (LivaNova) ring, which display 4:3 and 3:2 diameter ratios, respectively.Although implanted rings are rigid or semirigid, stiffness affects the likelihood of LV reverse remodeling and thus MR recurrence if basal segments are viable. 3n conclusion, MR recurrence is affected by the severity of localized and global LV remodeling and, thus, by LVESd, especially if measured early postoperatively.A n. 28 ring may not suffice to obtain adequate coaptation surface in case of severe tethering, and additional procedures may guarantee a durable repair, 4,5 avoiding