Função diastólica na estenose aórtica: correlação com NT-ProBNP e remodelamento pós-operatório / Correlation to NT-ProBNP and remodeling after cardiac surgery

FUNDAMENTO: A função diastólica em portadores de estenose aórtica (EAO) é pouco estudada. Não é possível estabelecer uma possível correlação entre biomarcadores e disfunção diastólica. OBJETIVO: Avaliar a função diastólica em portadores de EAO submetidos à troca valvar através de ecocardiografia transtorácica e correlacionar com valores de NT-proBNP. MÉTODOS: Estudamos 31 pacientes com EAO (11 homens), com idade entre 21 e 81 anos (média de 61±15 anos), submetidos a tratamento cirúrgico de EAO. Foi realizada dosagem sérica de NT-proBNP e o resultado, comparado com variáveis ecocardiográficas obtidas pelo Doppler pulsado em fluxo mitral, Doppler pulsado em veias pulmonares e Doppler tecidual, tanto no pré quanto no pós-operatório. RESULTADOS: Observou-se melhora na Fração de Ejeção (FE) de AE e Tempo de Relaxamento Isovolumétrico (TRIV), além de redução nos seguintes parâmetros: a) Relação da velocidade diastólica precoce mitral (onda E) com a velocidade do anel mitral (onda E´) (E/E'), b) Volume sistólico de átrio esquerdo (AE), c) Volume sistólico de AE indexado, d) Diâmetro diastólico de ventrículo esquerdo (DDVE), e) Diâmetro sistólico de VE (DSVE), f) Volume diastólico final (VDF), g) Massa indexada de VE e h) Relação Volume/Massa de ventrículo esquerdo (VE). Os valores do NT-proBNP correlacionaram-se de modo positivo com os diversos graus de disfunção diastólica, tanto no pré como no pós-operatório. CONCLUSÃO: 1) A cirurgia de troca valvar para correção de EAO resultou em melhora significativa da função diastólica ventricular. 2) Os valores de NT-proBNP correlacionaram-se positivamente com as variáveis ecocardiográficas que determinam disfunção diastólica, sendo o NT-proBNP um bom marcador para caracterizar essa disfunção em portadores de EAO.

BACKGROUND: Few data are available on diastolic function in patients with aortic stenosis (AOS) with indication of surgical treatment. A potential correlation between biomarkers and diastolic function has not been established. OBJECTIVE: The aim of our study was to evaluate diastolic function in patients with AOS waiting for aortic valve replacement (AVR) echocardiographically, and to verify its correlation with serum brain natriuretic peptide (NT-proBNP). METHODS: Thirty-one AOS patients (11 male), 21 to 81 years old (mean age, 61±15 years old) were studied before and after AVR. Diastolic function was assessed with Doppler methods: transvalvar mitral flow, tissue Doppler imaging (TDI) and pulmonary venous Doppler (PVD), correlating with serum brain natriuretic peptide (NT-proBNP) before and 6 months after AVR. RESULTS: Comparing pre to post-operative period, we observed an increase of the left atrial ejection fraction and isovolumetric relaxation time (IRT), and the decrease of the mitral velocity to early diastolic velocity of the mitral annulus ratio (E/E'), the difference between the pulmonary A wave duration and mitral A duration, left atrial systolic volume, left atrial systolic volume index, left ventricular diastolic diameter, left ventricular systolic diameter, end diastolic volume (LVEDV), left ventricular mass index, left ventricular volume and mass index ratio. The values of NT-proBNP were positively correlated to diastolic dysfunction, both before and after surgery. CONCLUSION: AOS patients' ventricular diastolic function improved after AVR. The biomarker NT-proBNP might be a useful biomarker of diastolic function in these patients, before and after AVR. NT-proBNP values show a positive correlation with echocardiographic variables that determine diastolic dysfunction, and is a good marker for the characterization of this dysfunction in AOS patients.

Incidência de distúrbios da condução atrioventricular e intraventricular após implante percutâneo da bioprótese valvar aórtica CoreValve / Incidence of atrioventricular and intraventricular conduction disorders after transcatheter aortic valve implantation with the CoreValve bioprosthesis

Introdução: O sistema de condução localizado no septo interventricular encontra-se anatomicamente contíguo ao anel valvar aórtico. Por isso, distúrbios na condução atrioventricular e intraventricular podem decorrer de inflamação, edema e estresse mecânico causados pelas hastes metálicas da bioprótese CoreValve. O objetivo deste estudo foi avaliar a incidência de distúrbios da condução atrioventricular e intraventricular após implante percutâneo da CoreValve. Método: Entre janeiro de 2008 e abril de 2010, 23 pacientes portadores de estenose aórtica foram submetidos a implante da CoreValve. A média de idade foi de 81 ± 8,3 anos, e 12 (52,1%) pacientes eram do sexo masculino. Resultados: Após o implante valvar, constataram-se as seguintes alterações na condução atrioventricular: 3 (13%) bloqueios atrioventriculares totais, 2 (8,7%) bloqueios atrioventriculares de 2º grau e 8 (34,8%) bloqueios atrioventriculares de 1º grau, sendo 4 (17,4%) novos e 4 preexistentes. Assim, distúrbios de condução mais avançados, como bloqueio atrioventricular de 2o grau e/ou bloqueio atrioventricular total ocorreram em 5 (21,7%) pacientes. Em relação aos distúrbios da condução intraventricular pós-implante, foram detectados 14 (60,9%) bloqueios completos de ramo esquerdo, sendo 2 (8,7%) com bloqueio completo de ramo direito e bloqueio completo de ramo esquerdo alternante. Nesta série, 7 (30,4%) pacientes foram submetidos a implante de marca-passo permanente, 6 (26,1%) deles por indicação absoluta. Todos os pacientes que apresentavam bloqueio completo de ramo direito antes do procedimento necessitaram do marca-passo permanente...

Background: There is a close anatomical relationship between the aortic valve annulus and the conduction system.Therefore, atrioventricular and intraventricular conduction disorders may occur as a result of inflammation, edema and mechanical stress caused by the metallic struts of the CoreValvebioprosthesis. The objective of this study was to evaluate the incidence of atrioventricular and intraventricular conduction disorders after percutaneous CoreValve implantation.Method: Between January 2008 and April 2010, 23 patients with aortic stenosis were submitted to CoreValve bioprosthesis implantation. Mean age was 81 ± 8.3 years and 12 (52.1%) patients were male. Results: After valve implantation, the following atrioventricular conduction disorderswere observed: 3 (13%) complete atrioventricular blocks, 2 (8.7%) 2nd degree atrioventricular blocks and 8 (34.8%) 1st degree atrioventricular blocks, of which 4 (17.4%) werenew and 4 were preexisting. Therefore, advanced conduction disorders, such as 2nd degree atrioventricular block and/orcomplete atrioventricular block were observed in 5 (21.7%) patients. As to post-implant intraventricular conductiondisorders, 14 (60.9%) left bundle branch blocks were observed, 2 (8.7%) of them with alternating right bundle branch block and left bundle branch block. In this series, 7 (30.4%) patients received a permanent pacemaker, 6 (26.1%) of them with absolute indication. All of the patients withright bundle branch block before the procedure required permanent pacemaker implantation. Conclusion: Atrioventricular conduction disorders and, specially, left bundle branch block are common after percutaneous implantation of the CoreValve prosthesis. Permanent pacemaker is required in approximately one fourth of the cases. The presence of pre-implant right bundle branch block is related to a greater risk of developing advanced conduction disorders.

Relationship between N-terminal pro-B type natriuretic peptide and extensive echocardiographic parameters in mild to moderate aortic stenosis.

CONTEXT: The N-terminal pro-B type natriuretic peptide levels (NT pro-BNP) are increased in cases of volume or pressure overload. AIMS: To examine NT pro-BNP levels and enclose whether any relationship is present between the levels of NT pro-BNP and extensive echocardiographic parameters in asymptomatic patients with mild to moderate aortic stenosis (AS). SETTINGS AND DESIGN: A cross-sectional study about the NT pro-BNP levels was conducted in 37 asymptomatic AS patients and compared with 40 controls. METHODS: Patients < 70 years old with mild to moderate AS with a peak transaortic gradient > 20 mm Hg in transthoracic echocardiogram were included in our study. Extensive echocardiographic parameters and NT pro-BNP levels were obtained from these patients and these indices were compared with the control population selected from the patients who had similar clinical characteristics with the AS patients. STATISTICAL ANALYSIS: NT-proBNP values were found to be distribution free. Spearman correlation coefficient was used for correlation analysis. Mean values were compared by the Kruskal-Wallis test. RESULTS: The NT pro-BNP levels were increased in patients with AS (median; interquartiles range: 686 [449-855] pg/mL vs. 140 [116-150] pg/mL, P < 0.001). Among patients with AS, when correlation analysis was performed mean transaortic gradient, aortic valve area index, myocardial performance index, E(m)/A(m) ratio, left-ventricular mass index (LVMI) and E/E(m) ratio had correlations (r=0.38, P = 0.026; r=-0.46, P =0.008; r=0.19, P =0,049; r=-0.22, P =0.04, r=0.49, P =0.003 and r=0.53, P <0.001 respectively) with plasma NT pro-BNP levels. The LVMI (r = 0.49, P = 0.003) and E/E(m) ratio (r = 0.53 P < 0.001) have the strongest correlations when compared to other parameters. CONCLUSION: Plasma NT pro-BNP levels are increased in even asymptomatic patients with AS and correlated with several echocardiographic parameters related to severity of AS and degree of diastolic dysfunction. As a result, NT pro-BNP levels may be used in the follow-up of asymptomatic patients having mild to moderate AS.