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Analysis of the hemodynamics of the renal artery of normal fetuses by the color Doppler method
Author(s) -
Iura T.,
Higashiyama N.,
Miyazaki S.,
Ooshima K.,
Makinoda S.
Publication year - 2001
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1046/j.1469-0705.2001.abs16-3.x
Subject(s) - medicine , renal artery , fetus , hemodynamics , gestational age , renal blood flow , kidney , cardiology , vascular resistance , hilum (anatomy) , pregnancy , surgery , biology , genetics
Objectives: Urination interval or the pulsatility index (PI) and resistance index (RI) of the renal artery have often been measured to assess renal function of fetuses in cases such as oligoamnion. However, PI and RI do not reflect dynamic changes of the renal artery not only in fetuses with oligoamnion, etc. but also in normal fetuses. For this reason, we have analyzed the blood flow of the renal artery in normal fetuses using new indexes to clarify its hemodynamics. Study methods: The healthy fetuses of 33 pregnant women participated in this study with informed consent of mothers in their 20–40th week of pregnancy. The blood flow of the renal arteries was examined at the renal hilum using a color Doppler apparatus using the indexes of PI, RI, maximum velocity (V max ), mean velocity time (VMT), sectional area of the renal artery (AREA) and renal blood flow (RBF). The gestational age of the fetuses were divided into five groups of 20–24, 25–28, 29–32, 33–36, and 37–40 weeks through longitudinal study. Statistical analysis was performed using Fisher's protected least significant difference. Results: RI did not show marked changes throughout all gestational age. In contrast, the V max and RBF of the renal artery for the 20–24 weeks group were 21.98 cm/s and 0.049 L/min, respectively (mean), and those for the 25–28 weeks group were significantly higher at 27.68 cm/s and 0.003 L/min, respectively ( P < 0.05 and 0.05, respectively). The same applied for VMT and AREA. The 95% confidence interval of the V max of the right renal artery was 23.2–20.8, 28.7–26.6, 33.7–31.4, 34.6–32.8 and 40.7–37.8 for the 20–24, 25–28, 29–32, 33–36 and 37–40 weeks group, respectively. Thus, we have determined the 95% confidence interval for the V max , VMT, AREA and RBF of the renal artery of fetuses in different stages of development. Conclusions: The present study demonstrated that V max , VMT, AREA and RBF were more useful than either PI or RI in assessing the hemodynamics of the renal artery of fetuses in different stages of development. Moreover, we have clarified the normal range of the V max , VMT, AREA and RBF for the renal artery of fetuses after the 20th week of gestation. These results are very useful to assess the renal function of fetuses.