Is myocardial performance index an independent echocardiographic marker of death in children with idiopathic dilated cardiomyopathy?
BACKGROUND
Myocardial performance index (MPI) was reported as a parameter of ventricular systolic and diastolic function, as well as a useful tool to predict the outcome in patients with ventricular dysfunction.


OBJECTIVE
To compare MPI with classical echocardiographic parameters as an independent marker of death in children with idiopathic dilated cardiomyopathy (IDCM).


METHODS
Fifty-five children (13 deaths) underwent 104 echocardiograms from January 1996 to May 2005. Right ventricle (RV) MPI and left ventricle (LV) MPI, and 9 classical echocardiographic parameters (left atrium [LA]/body surface area [BSA], distance between mitral E point and ventricular septum, LV mass/body surface area, RV shortening fraction, LV end-systolic and end-diastolic dimensions/body surface area, LV ejection fraction, fiber circumferential shortening velocity, and mitral deceleration time) were compared. Statistical analysis was performed by chi-square, Pearson's correlation and Student t-test, Kaplan-Meier method, Cox's method, and receiver operating curve (ROC). Statistical significance was considered with alpha<0.05 and p=0.80].


RESULTS
Univariate analysis showed that all studied parameters were markers of death. There was a high correlation between RVMPI and LVMPI (r=0.847]-p=0.0001]); therefore, to avoid bias, RVMPI was discharged from multivariate analysis. In the deceased group, moderate/severe mitral regurgitation was frequent (76.9%; confidence interval [CI[ 95%=46.2%- 94.9%) and it was considered in multivariate analysis. In Cox's multivariate analysis, LVMPI was the only independent marker of death (p=0.0213]). The ideal cut-off was 0.63 with 92.3% sensitivity, 66.7% specificity, and fitted ROC area=0.918].


CONCLUSIONS
In children with IDCM, LVMPI is an independent marker of death.
Azevedo
Vitor Manuel P
VM
Research Department, National Institute of Cardiology, Rio de Janeiro, Brazil. vitoraze8@hotmail.com
Albanesi Filho
Francisco M
FM
Santos
Marco Aurélio
MA
Castier
Márcia B
MB
Tura
Bernardo R
BR
Amino
José Geraldo
JG
Da Cunha
Maria Ourinda Mesquita
MO
D000293:Adolescent; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004452:Echocardiography; D006801:Humans; D007223:Infant; D015233:Models, Statistical; D009200:Myocardial Contraction; D012372:ROC Curve; D015996:Survival Rate; D016276:Ventricular Function
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