Atrial reservoir function by strain rate imaging in asymptomatic mitral stenosis: prognostic value at 3 year follow-up.

AIMS: Assessment of left and right systolic atrial reservoir function in asymptomatic mitral stenosis (MS) by strain and strain rate imaging (SRI) and their prognostic power at 3 year follow-up was the purpose of this study. There is clear indication to treat (by surgery or percutaneous valvotomy) symptomatic patients with MS, whereas for the asymptomatic ones, the question is much debated. So, we need new echocardiographic parameters helpful for the management of asymtomatic patients. Atrial reservoir function by SRI could help in evaluation of these patients. METHODS AND
RESULTS: Fifty-three asymptomatic patients with MS and 53 healthy controls were evaluated by the standard echo-Doppler study [mitral valve (MV) area, mean gradient, systolic pulmonary pressure, left atrial (LA) width, LA volumes, LA compliance index] and by Doppler myocardial imaging (velocity, strain, and SR of both atria). The endpoint at 3 year follow-up was symptoms, hospitalization for cardiac cause, atrial fibrillation, thrombo-embolic events, valvular surgery, or percutaneous commissurotomy. LA width, volumes, and systolic pulmonary pressure were significantly increased in MS patients (P < 0.001). Atrial myocardial velocities and deformation indices were significantly compromised in MS patients (P < 0.0001). Significant correlation was found between atrial myocardial velocity and MV area (by pressure half-time method: P = 0.019, R = 0.41; by planimetric method: P = 0.016, R = 0.43). Peak systolic LA myocardial strain and SR were significantly correlated with atrial volumes (strain: P = 0.03, R = -0.28; SR: P = 0.0008, R = -0.42), with atrial compliance index (strain: P = 0.04, R = 0.26; SR: P = 0.04, R = 0.16), with atrial ejection fraction (strain: P < 0.0001, R = 0.56; SR: P = 0.03, R = 0.43). At 3 year follow-up, 22 (41%) patients had events. Comparing the MS patients who had events during the 3 year follow-up with those who did not, the former had bigger LA volumes, although these parameters did not reached a significant value, whereas atrial myocardial systolic SR was significantly impaired in patients with events. In multivariate analysis, the best predictor of adverse events was LA peak systolic SR average (P = 0.04; coefficient: 0.113; SE: 0.055; cut-off value of 1.69 s(-1) for LA peak systolic SR average) with a sensitivity of 88%, specificity of 80.6%, area under the receiver operating characteristic curve of 0.852 (SE: 0.048; 95% CI: 0.74-0.93, P = 0.0001).
CONCLUSION: Atrial myocardial deformation properties, assessed by SRI, are abnormal in asymptomatic patients with rheumatic MS. The degree of this impairment is predictor of events in a 3 year follow-up. SRI could be helpful in decision-making of asymtomatic patients with MS.