Disfunção ventricular no pós-operatório da intervenção cirúrgica para correção dos defeitos congênitos da Tetralogia de Fallot: estudo de correção clínica e anatomopatológica / Ventricular dysfunction after the surgical repair of Fallot´s tetralogy: a clinical and anatomopathological study

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

It was investigate prospectively the histopathological myocardial remodeling in children submitted to surgical repair of Fallots tetralogy, in order to detect possible factors associated to postoperative (PO) echocardiographic findings of systolic or diastolic ventricular dysfunction. Patients and Methods: 23 consecutive Fallot patients (14 males), aged 12 to 186 months (mean=39.6, median=23 months) were enrolled in the study. Tissue Doppler echocardiographic analysis (isovolumic acceleration-IVA, systolic myocardial velocity-Sand early diastolic myocardial velocity-E) was performed in three moments for both ventricles: before surgery, within the first three postoperative days and later, between the 30th and 90th PO days. During surgery, besides the anomalous infundibular bands resected, subendocardial biopsy samples from the right ventricular (RV) inflow tract and of the left ventricle (LV), through the ventricular septal defect, were obtained for histopathological morphometric evaluation: degree of cell hypertrophy, interstitial collagen (Sirius-red) and capillarity (immunohistochemistry against Factor-VIII). Troponin-T levels were measured before and after surgery. The electrocardiogram performed before and after surgery, some clinical features and previous use propranolol were considered. This study was approved by the Ethical Committee of our Institution. Results: the right ventricular cardyomyocytes showed a significant hypertrophy. The interstitial collagen was increase in both right and left ventricle. The capillary area fraction did not differ among the biopsy samples analyzed. IVA of the RV decreased significantly at the third echocardiographic evaluation (p=0.006) and correlated negatively with the diameter of the RV cardyomyocytes (r= -0.59; p=0.006). Emeasured at the RV decreased significantly in both PO periods (p<0.001) and showed a significant negative correlation with the percentage of interstitial myocardial collagen (r=-0.525; p=0,044). Troponin-T levels increased postoperatively in all patients (27.7 ±18,6ng/ml and 15.9+11.3ng/ml - second and third PO days) and correlated positively with the cardiopulmonary bypass and cross clamping times (p=0.019 and 0.018 respectively). The QRS interval increased significantly in the PO period. The patients in whom the PO electrocardiogram showed an increase of the QRS greater than 40ms, showed a greater interstitial collagen area fraction in the right ventricle inflow tract. Conclusions: Myocardial remodeling present preoperatively, as judged by the morphometric histopathological evaluation of cell hypertrophy and interstitial collagen, influenced respectively the medium term PO systolic and diastolic right ventricular function of repaired Fallot patients.

ASSUNTO(S)

tetralogia de fallot/cirurgia heart defects child. criança colágeno collagen disfunção ventricular cardiopatias congênitas propranolol ventricular dysfunction troponina t troponin t propranolol tetralogy of fallot/surgery hipertrofia congenital hypertrophy

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