Atrial function as a guide to timing of intervention in mitral valve prolapse with mitral regurgitation.JACC Cardiovasc Imaging 2014; 7(3):225-32JC
The purpose of this study was to determine the clinical utility of left atrial (LA) functional indexes in patients with mitral valve prolapse (MVP) and mitral regurgitation (MR).
Timing of surgery for MVP remains challenging. We hypothesized that assessment of LA function may provide diagnostic utility in these patients.
We studied 192 consecutive patients in sinus rhythm with MVP, classified into 3 groups: moderate or less MR (MOD group, n = 54); severe MR without surgical indication (SEV group, n = 52); and severe MR with ≥1 surgical indication (SURG group, n = 86). Comparison was made with 50 control patients. Using 2D speckle imaging, average peak contractile, conduit, and reservoir atrial strain was recorded. Using Simpson's method we recorded maximal left atrial volume (LAVmax) and minimal left atrial volume (LAVmin), from which the total left atrial emptying fraction (TLAEF) was derived: (LAVmax-LAVmin)/LAVmax × 100%.
TLAEF was similar in the MOD and control groups (61% vs. 57%; p = NS), was reduced in the SEV group (55%; p < 0.001 vs. control group), and markedly lower in the SURG group (40%; p < 0.001 vs. other groups). Reservoir strain demonstrated a similar pattern. Contractile strain was similarly reduced in the MOD and SEV groups (MOD 15%; SEV 14%; p = NS; both p < 0.05 vs. control group 20%) and further reduced in the SURG group (8%; p < 0.001 vs. other groups). By multivariate analysis, TLAEF (odds ratio [OR]: 0.78; p < 0.001), reservoir strain (OR: 0.91; p = 0.028), and contractile strain (OR: 0.86; p = 0.021) were independent predictors of severe MR requiring surgery. Using receiver-operating characteristic analysis, TLAEF <50% demonstrated 91% sensitivity and 92% specificity for predicting MVP with surgical indication (area under the curve: 0.96; p < 0.001).
We report the changes in left atrial function in humans with MVP and the relationship of LA dysfunction to clinical indications for mitral valve surgery. We propose that the findings support the utility of quantitative assessment of atrial function by echocardiography as an additional tool to guide the optimum timing of surgery for MVP.