RESUMO
INTRODUCTION: BNP (brain-type natriuretic peptide) is released by cardiomyocytes, as a pro-hormone, in response to parietal stress augmentation and systemic endothelial dysfunction, and then Pro-BNP is cleaved into: NT-Pro-BNP and BNP fragment in 1:1 ratio. BNP is considered an important component of the adaptative mechanism that helps to reduce the load on the myocardium, through systemic vasodilatation, reduction in venous return and reduction in vascular volume. Hypertensive Gestational Syndromes (HGS) are considered to share those mechanisms, but the role of NT-Pro-BNP to evaluate maternal outcomes, is not well defined. OBJECTIVES: Evaluate the correlation between NT-Pro-BNP: in Normotensive Pregnant Women (NPW) and HGS with established markers of adverse maternal outcomes in HGS. METHODS: We performed a transversal case-control study to analyze NT-Pro-BNP in 68 patients with HGS vs 80 NPW admitted at a private hospital, and to evaluate its correlation with established clinical and blood markers of maternal outcomes at hospital admission. Patients with renal chronic failure, previous cardiac disease and mola were excluded. We used the Pearson and Kendall correlation test for quantitative variables and the non-parametrical Mann-Whitney test for qualitative variables. RESULTS: The average maternal age was: NPW 33.2 years, HGS 33.8 years; average gestational age at delivery: NPW 38.5 weeks, HGS 35.3 weeks; first pregnancy: NPW 36%, HGS 56%; birth average weight: NPW 3351.6g, HGS 2615.5g; media NT-Pro-BNP: NPW 59.7pg/ml, HGS 704.8pg/ml. None of the NPW had high levels of NT-Pro-BNP. In the HGS group: 57% had preeclampsia, 10% HELLP, 25% gestational hypertension and 8% chronic hypertension. In the HGS media values for: proteinuria 1.5g/24h, glutamic-oxalacetic transaminase 86 UI/L, platelets 231,688/mm(3), glutamic-pyruvic transaminase 100 UI/L, uric acid 48mg/dl, hematocrit 33%, alkaline phosphatase 152 UI/L, lactic dehydrogenase 284 UI/L. In the HGS the following significant correlations were found: for NT-Pro-BNP relation to: proteinuria (0.34 p=0.001), glutamic-oxalacetic transaminase (0.375 p=0.001), platelets (-0.353 p=0.001), glutamic-pyruvic transaminase (0.317 p=0.001), uric acid (0.398 p=0.001), hematocrit (-0.183 p=0.048), gestational age at delivery (-0.29 p=0.002), birth average weight (-0.23 p=0.018), cardiac failure ( p=0.001), number of used anti-hypertensive drugs (0.367 p=0.004), lactic dehydrogenase (0.65 p=0.001). The media NT-Pro-BNP was: 936pg/ml in preeclampsia , 1909pg/ml in HELLP, 150pg/ml in gestational hypertension and 107pg/ml in chronic hypertension. The highest NT-Pro-BNP level was 12,386pg/ml in a patient with systolic dysfunction (LVEF: 35%) associated with preeclampsia. After delivery, 13% HGS women had persistent hypertension post-partum, and this did not correlate with the level of NT-Pro-BNP at hospital admission. CONCLUSION: NT-Pro-BNP significantly correlates with established markers of adverse maternal outcomes in HGS, probing to be useful in routine maternal evaluation in this setting.
