ACTA ENDOCRINOLOGICA (BUC)

Introduction: Pseudo-primary hyperaldosteronism of pregnancy was previously reported by our group during correction in twin-to-twin transfusion syndrome (TTTS). Aim: Focus on plasma volume changes and renin-angiotensin (RAS) and aldosterone response in 45 TTTS patients requiring amnioreductions above 1000 ml for severe hydramnios. Methods: 45 patients necessitating placental surgery and amnioreduction >1000ml for severe TTTS, under local anesthesia, as previously described. Assesment of plasma volume variations (%ΔPV) and simultaneous assays of aldosterone, renin, angiotensin II and ANP performed by standard kits prior to, 6 hours after and 12-24 hours after procedure. Statistical results expressed as median and interquartile ranges for non-parametric data, after correction of post-op levels with %ΔPV. Results: Depletion of 1600 ml (1000-3700) amniotic fluid (extravascular depletion) unexpectedly increased the intravascular plasma volume by 20,38% and dramatically changed the hormonal picture of primary hyperaldosteronism. Aldosterone decreased from a median of 730 pg/ml (T0) to 553 pg/ml (T6) to 515,9 pg/ml (T24). ANP increased from 8,95 pg/ml (T0) to 14,51pg/ml (T6) to 19,9 pg/ml (T24) pg/ml (ANOVA p=0,0036), while renin and angiotenin II stayed unchanged (ANOVA p=0,91). Conclusion: Depletion of extracelular fluid (amnioreduction) is indicated for the correction of hyperaldosteronism in pregnancies with severe hydramnios, to reduce to normal the aldosteron levels without the interference of the renin-angiotensin system, while natriuretic activity increases through ANP and, possibly, other less known natriuretic factors .