Left atrial strain and strain rate before and following restrictive annuloplasty for ischaemic mitral regurgitation evaluated by two-dimensional speckle tracking echocardiography

Abstract

We retrospectively evaluated left atrial (LA) strain and strain rate (SR) before and after undersized mitral ring annuloplasty (UMRA) for chronic ischaemic mitral regurgitation (CIMR) with two-dimensional speckle-tracking echocardiography. Left atrial volumes, LA reservoir, LA conduit, LA contractile phases, and LA ejection fraction (LAEF) were measured in 95 CIMR patients who underwent coronary bypass grafting and UMRA. Left atrial peak global strain (ε), LA reservoir (SRp), LA conduit (SRE), and LA contractile phase (SRA) strain rates were obtained at the baseline and at the follow-up (median 41.5 months, interquartile range 23-61). Based on the recurrence of mitral regurgitation (MR) at the follow-up, the patients were divided into two groups: patients with (group MR+, n = 30) or without (group MR-, n = 65) recurrent MR. Twenty age-and gender-matched healthy adults were controls. In the MR- group, baseline ε (P < 0.001), SRP (P < 0.001), SRE (P < 0.001), and SRA (P < 0.001) were enhanced, while in MR+ group, ε (P < 0.001), SRP (P = 0.03), SRE (P = 0.03), and SRA (P = 0.003) were worse than controls. At the follow-up, none of these indices changed in the MR+ group while all returned to normal values in patients belonging to the MR- group. Left atrial deformation correlated with corresponding volumetric parameters. Furthermore, we found a direct correlation between SRE and early peak diastolic velocity (E) (ρ = 0.52, P = 0.02) and E-wave deceleration time (ρ = 0.50, P = 0.02). Finally, there was a strong correlation between ε, SRP, and SRA (ρ = 0.72, P < 0.001 and ρ = 0.79, P < 0.001, respectively) and SRE (ρ = 0.69, P < 0.001 and ρ = 0.71, P < 0.001, respectively). Finally, ε, SRP, and SRE (all, P < 0.001) were co-factors associated to recurrent MR. Left atrial peak global strain, peak systolic SR, and peak early diastolic SR were cofactors associated to recurrent MR. The assessment of LA strain and SR, in addition to other echocardiographic parameters, can be helpful in detecting patients undergoing UMRA who are unlikely to benefit from annuloplasty.