Could real-time sonoelastography-measured placental strain ratio (PSR) value be a soft marker for the diagnosis of intrahepatic cholestasis of pregnancy?: A case-control study and short reviews

Abstract

Diagnosis of intrahepatic cholestasis of pregnancy (ICP) is often decided upon with typical pruritus supported by elevated serum bile acid levels. However, there is confusion regarding the absolute reference range for serum bile acid. To confirm the utility of Placental Strain Ratio (PSR) measurement as a marker for the diagnosis of ICP and to reveal the extent to which it is correlated with serum bile acid concentration. A case-control study was conducted. The case group included 29 patients who were admitted to our hospital in the second or third trimester of pregnancy with typical itching and were clinically diagnosed with ICP with >10 mmol/L serum bile acid. The first 45 pregnant women were assigned to a control group. Real-time tissue elastography software was used for ultrasound assessment of all pregnant placentas. Software was used to estimate the SR values. Biochemical liver function parameters, hemograms, serum bile acid levels, and SR values were compared between these groups. PSR was found to predict the development of cholestasis with poor discrimination (area under the curve [AUC] = 0.524; 95% CI = 0.399–0.646). The optimal threshold value with the best sensitivity and specificity rates was calculated to be 0.46 PSR. ICP developed significantly more frequently in the low PSR group than in the high PSR group (60% vs 29.3%, P = .05, odds ratios [OR] = 0.276, 95% CI = 0.069–1.105). No correlation was found between the PSR and bile acid levels (rho = −0.029, P = .816). PSR values can support the diagnosis of ICP, predict serum bile acid levels, and can be used as soft markers.