N-terminal proBNP levels in patients with Chagas disease: a marker of systolic and diastolic dysfunction of the left ventricle.
OBJECTIVE
NT-proBNP levels are known to be elevated in systolic and diastolic dysfunction. Doppler indices of diastolic dysfunction (DD) have been shown to have prognostic value in patients with Chagas' cardiomyopathy (CC). However, the additional value of NT-proBNP levels in further stratifying these patients according to DD has not been established. This study analyzed the correlation of N-terminal proBNP (NT-proBNP) levels with systolic and diastolic function in patients with CC.


RESULTS
NT-proBNP levels were measured in 59 patients with dilated cardiomyopathy due to Chagas disease without other systemic illness that were studied by Doppler echocardiography, including left atrial volume (LAV) calculation and tissue Doppler evaluation of LV longitudinal function. Univariate analysis showed a strong correlation of NT-proBNP values with LVEF (r=-0.733, p<0.001) and a weak correlation with most Doppler echocardiographic parameters of diastolic function. On a multivariate analysis, LVEF and LAV volume emerged as correlating with elevated levels of the NT-proBNP. Patients with restrictive filling pattern (n=10), when compared to other patterns of DD, (n=49), showed a lower LVEF (25.4+/-6.4% vs. 39.8+/-9.4, p<0.001), a larger LAV (50.1+/-17.2 vs. 37.7+/-15.6 ml/m(2), p=0.004) and higher NT-proBNP levels (median+/-IQR: 3488+/-3056 vs. 492+/-700 pg/dl, p<0.001). A marked elevated concentration of NT-proBNP (> or =800 pg/ml) had a sensitivity of 90.0%, specificity of 70.5%, positive predictive value of 40.9% and negative predictive value of 96.9% for detecting a restrictive filling pattern.


CONCLUSIONS
In patients with CC, NT-proBNP augmentation is a marker of LV dysfunction, with higher levels correlating with the more severe forms of both systolic and diastolic dysfunction.
Barbosa
Marcia M
MM
Ecocenter, Hospital Socor, Av. Contorno 10500, 30110-140 Belo Horizonte, MG, Brazil.
Nunes
Maria do Carmo P
Mdo C
Ribeiro
Antônio Luiz P
AL
Barral
Marselha M
MM
Rocha
Manoel Otávio C
MO
D000328:Adult; D000368:Aged; D015415:Biomarkers; D002311:Cardiomyopathy, Dilated / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014355:Chagas Disease / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D003971:Diastole; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011446:Prospective Studies; D013318:Stroke Volume; D013599:Systole; D013997:Time Factors; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging
D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain