Is Cystatin-C A Reliable Prognostic Parameter in Terms of Renal Functional Reserve for Antenatally Diagnosed Infravesical Obstruction?

Abstract

Purpose We investigated the prognostic power of cystatin-c in determining renal functional outcome in patients with antenatally diagnosed infravesical obstruction (IVO). Material and Methods A total of 10 fetuses (IVO group) with prenatal ultrasonographic findings of bladder outlet obstruction were enrolled to this study.Amniotic fluid and fetal urine samples were obtained in IVO group. Control group consisted of 25 fetuses, who have undergone amniocentesis for obstetric reasons.Three consecutive bladder punctures (48 hours apart) were performed to obtain fetal urine sample. In addition to standart prognostic parameters (sodium, chloride, calcium, protein, beta-2 microglobulin, osmolarity), cystatin-c was measured both in urine and amniotic fluid samples. Results Mean maternal age was 26.9 (22-33) years in IVO group and 28.2 (22-34) years in control group (p > 0.05). In IVO group (n = 10), 9 fetuses with poor prognostic parameters died either in-utero (n = 4) or early postnatally (n = 5). The only fetus with favorable parameters survived postnatally. His serum creatinine level was 0.2 mg/dl at 1 year follow-up after valve ablation. Mean fetal urine levels of cystatin-c was 1.59 ± 1.87, 1.39 ± 1.76 and 1.68 ± 1.79 mg/l in serial punctures. The difference between second and third bladder punctures was significant in terms of urine cystatin-c level (p = 0.015). Mean amniotic fluid cystatin-c level was 2.11 ± 0.4 mg/l in IVO group and 1.12 ± 0.20 mg/l in control group. There was a significant correlation between fetal urine (second puncture) and amniotic fluid in terms of cystatin-c level (p = 0.030, r = 0.717). Amniotic fluid cystatin-c level was significantly higher in fetuses with suspected infravesical obtsruction compared to control group (p Conclusions Amniotic fluid may represent fetal urine sample in suspected antenatal infravesical obstruction in terms of cystatin-c level.Amniotic fluid cystatin-c level was significantly higher in obstructed fetuses compared to normal controls. Cystatin-c level in amniotic fluid sample may be sufficient to give prognostic information in antenatally diagnosed infravesical obstruction.