N-terminal prohormone brain natriuretic peptide (NT-proBNP) as a noninvasive marker for restrictive syndromes

Constrictive pericarditis (CP) and restrictive cardiomyopathy share many similarities in both their clinical and hemodynamic characteristics and N-terminal prohormone brain natriuretic peptide (NT-proBNP) is a sensitive marker of cardiac diastolic dysfunction. The objectives of the present study were to determine whether serum NT-proBNP was high in patients with endomyocardial fibrosis (EMF) and CP, and to investigate how this relates to diastolic dysfunction. Thirty-three patients were divided into two groups: CP (16 patients) and EMF (17 patients). The control group consisted of 30 healthy individuals. Patients were evaluated by bidimensional echocardiography, with restriction syndrome evaluated by pulsed Doppler of the mitral flow and serum NT-proBNP measured by immunoassay and detected by electrochemiluminescence. Spearman correlation coefficient was used to analyze the association between log NT-proBNP and echocardiographic parameters. Log NT-proBNP was significantly higher (P < 0.05) in CP patients (log mean: 2.67 pg/mL; 95 percentCI: 2.43-2.92 log pg/mL) and in EMF patients (log mean: 2.91 pg/mL; 95 percentCI: 2.70-3.12 log pg/mL) compared with the control group (log mean: 1.45; 95 percentCI: 1.32-1.60 log pg/mL). There were no statistical differences between EMF and CP patients (P = 0.689) in terms of NT-proBNP. The NT-proBNP log tended to correlate with peak velocity of the E wave (r = 0.439; P = 0.060, but not with A wave (r = -0.399; P = 0.112). Serum NT-proBNP concentration can be used as a marker to detect the presence of diastolic dysfunction in patients with restrictive syndrome; however, serum NT-proBNP levels cannot be used to differentiate restrictive cardiomyopathy from CP.

Níveis séricos de NT pro-BNP: relação com função sistólica e diastólica nas miocardiopatias e pericardiopatias / Serum NT pro-BNP: relation to systolic and diastolic function in cardiomyopathies and pericardiopathies

FUNDAMENTO: O NT pro-BNP é marcador de disfunção sistólica e diastólica. OBJETIVO: Determinar os níveis de NT pro-BNP em pacientes com cardiopatia chagásica, hipertrófica, restritiva e afecções pericárdicas, e sua relação com medidas ecocardiográficas de disfunção sistólica e diastólica. MÉTODOS: Cento e quarenta e cinco pacientes foram divididos nos respectivos grupos: 1) cardiopatia chagásica (CCh) - 14 pacientes; 2) miocardiopatia hipertrófica (CMH) - 71 pacientes; 3) endomiocardiofibrose (EMF) - 26 pacientes; 4) derrame pericárdico (DP) - 18 pacientes; 5) e pericardite constritiva (PC) - 16 pacientes. Foi constituído um grupo-controle de 40 indivíduos sem doença cardíaca. O grau de acometimento miocárdico e o derrame pericárdico foram avaliados pelo ecocardiograma bidimensional e a restrição pelo Doppler pulsátil do fluxo mitral. O diagnóstico de PC foi confirmado por meio da ressonância magnética. Os níveis de NT pro-BNP foram medidos por imunoensaio com detecção por eletroquimioluminescência. RESULTADOS: O NT pro-BNP esteve aumentado (p < 0,001) na CCh (mediana 513,8 pg/ml), CMH (mediana 848 pg/ml), EMF (mediana 633 pg/ml), PC (mediana 568 pg/ml), DP (mediana 124 pg/ml), quando comparados ao grupo-controle (mediana 28 pg/ml). Não foram observadas diferenças estatisticamente significativas entre PC e EMF (p = 0,14). No grupo hipertrófico, o NT pro-BNP correlacionou-se com tamanho de átrio esquerdo (r = 0,40; p < 0,001) e relação E/Ea (p < 0,01). No grupo restritivo, houve uma tendência de correlação com pico de velocidade de onda E (r = 0,439; p = 0,06). CONCLUSÃO: O NT pro-BNP encontra-se aumentado nas diversas miocardiopatias e afecções pericárdicas, e apresenta relação com o grau de disfunção sistólica e diastólica.

BACKGROUND: NT pro-BNP is a marker of systolic and diastolic dysfunction. OBJECTIVE: To determine NT pro-BNP levels in patients with chagasic, hypertrophic, and restrictive heart diseases, as well as with pericardial diseases, and their relation to echocardiographic measurements of systolic and diastolic dysfunction. METHODS: A total of 145 patients were divided into the following groups: 1) Chagas' heart disease (CHD) - 14 patients; 2) hypertrophic cardiomyopathy (HCM) - 71 patients; 3) endomyocardial fibrosis (EMF) - 26 patients; 4) pericardial effusion (PE) - 18 patients; and 5) constrictive pericarditis (CP) - 16 patients. The control group was comprised of 40 individuals with no heart disease. The degree of myocardial impairment and pericardial effusion were assessed by two-dimensional echocardiography and the degree of restriction by pulsed Doppler transmitral flow. The diagnosis of CP was confirmed through magnetic resonance imaging. NT pro-BNP levels were determined through electrochemiluminescence immunoassay. RESULTS: NT pro-BNP was increased (p < 0.001) in CHD (median = 513.8 pg/ml), HCM (median = 848 pg/ml), EMF (median = 633 pg/ml), CP (median = 568 pg/ml), and PE (median = 124 pg/ml), when compared with the control group (median = 28 pg/ml). No statistically significant differences were found between CP and EMF (p = 0.14). In the hypertrophic group, NT pro-BNP was correlated with left atrial size (r = 0.40; p < 0.001) and with E/Ea ratio (p < 0.01). In the restrictive group, there was a trend of correlation with E-wave peak velocity (r = 0.439; p = 0.06). CONCLUSION: NT pro-BNP is increased in the different cardiomyopathies and pericardial diseases and is correlated with the degree of systolic and diastolic dysfunction.