Doppler velocimetry of maternal renal circulation in pregnancy-induced hypertension

Comparative sonographic assessment of renal volume and arterial Doppler velocimetric indices among women with pregnancy-induced hypertension and normotensive controls in Northern Nigeria

Introduction

Pregnancy-induced hypertension is a global public health problem, worsening maternal morbidity and mortality. Renal complications have additional devastating consequences on maternal morbidity. Renal Doppler ultrasound is a valuable tool in the management of pregnancy-induced hypertension. It helps in the assessment of renal hemodynamics with the potential to monitor renal function and predict complications. We aimed to determine the relationship between the renal volume and arterial Doppler velocimetric indices in pregnancy-induced hypertension and matched normotensive controls.

Methods

Following the documentation of demographic and basic obstetric characteristics of 150 women with pregnancy-induced hypertension and an equal number of their matched controls, a 3.5-MHz convex transducer was used to measure the maternal renal volumes and renal arterial Doppler velocimetric indices (peak systolic velocity, end diastolic velocity, resistive index, pulsatility index, and systolic-diastolic radio). Student's t-test and linear regression were used to determine the differences and relationships between the quantitative variables among women with pregnancy-induced hypertension and their controls. The association chi-square test was used to determine the association between the qualitative and categorical variables. A p-value of less than 0.05 was considered significant.

Results

The mean renal volume of pregnancy-induced hypertension patients is higher bilaterally when compared to normotensive women. The mean peak systolic velocity and resistive index in pregnancy-induced hypertension patients were significantly higher compared to normotensives (59.13 ± 13.5 vs 54.19 ± 9.8 cm/s; p < 0.001) and (0.74 ± 0.2 vs 0.68 ± 0.3).

Conclusion

The maternal renal volume and peak systolic velocity of the renal arteries are significantly higher in women with pregnancy-induced hypertension compared to normotensives.

Waveform parameters of retrobulbar vessels in glaucoma patients with different demographics and disease severity

Introduction:

To identify novel velocity waveform parameters of the ophthalmic artery and central retinal artery by computer-aided image processing of Doppler ultrasonography measurements, and to evaluate correlations between the waveform parameters and different demographics and disease severity of open-angle glaucoma patients.

Methods:

Thirty-six images of 36 open-angle glaucoma patients were considered. A semiautomated image processing code was used to detect the digitalized ophthalmic artery and central retinal artery velocity waveforms and to extract the waveform parameters. Concordance correlation coefficient, two-sample t-test, and Pearson’s correlation coefficient were used to test for similarities, differences, and associations among variables.

Results:

Female glaucoma patients showed a statistically higher ophthalmic artery normalized distance between ascending and descending limb (p = 0.004), hypertensive glaucoma patients a statistically higher ophthalmic artery peak systolic velocity time (p = 0.025), glaucoma patients with hyperlipidemia a statistically higher ophthalmic artery resistivity index (p = 0.023) and a statistically higher ophthalmic artery peak systolic velocity acceleration (p = 0.025), glaucoma patients with cardiovascular diseases a statistically lower central retinal artery normalized distance between ascending and descending limb of the wave (p = 0.033) and a statistically higher central retinal artery period (p = 0.028), and patients with different body mass index a statistically different central retinal artery normalized distance between ascending and descending limb of the wave (p = 0.016). Groups with different disease severity, classified following the Brusini glaucoma staging system 2, showed statistically different central retinal artery normalized distance between ascending and descending limb of the wave (p < 0.001) and central retinal artery period (p = 0.016). No statistical differences were found in regard to race, diabetes status, glaucoma family history, and smoking.

Discussion:

Ophthalmic artery and central retinal artery computer-aided analysis of velocity waveforms could identify novel waveform parameters capable of differentiating among different demographics and disease severity of open-angle glaucoma patients.

Maternal renal artery Doppler sonographic changes in pregnancy-induced hypertension in South West Nigeria

BACKGROUND

To evaluate the renal arterial hemodynamic changes caused by pregnancy-induced hypertension using Doppler ultrasonography.

MATERIALS AND METHODS

Eighty (80) subjects with pregnancy-induced hypertension (PIH) and 160 controls (80 pregnant normotensive women and 80 healthy, non-pregnant women) underwent triplex renal sonography prospectively to determine their renal volumes and right renal artery Doppler indices.

RESULTS

The peak systolic velocity, end diastolic velocity, pulsatility index, systolic/diastolic ratio and acceleration time were respectively significantly higher in the PIH group (68.67 cm/s, 21.55 cm/s, 1.23, 3.38, 123.2 ms) than the pregnant, normotensive group (65.19 cm/s, 20.27 cm/s, 0.88, 3.35, 61.14 ms) and healthy, non-pregnant group (52.06 cm/s, 18.27 cm/s, 0.84, 2.90, 68.48 ms). Resistivity index was also increased in the PIH group, but this was not statistically significant. Conversely, the systolic acceleration was significantly lower in the PIH group (6.06 m/s(2)) compared to the pregnant, normotensive group (11.82 m/s(2)) and healthy, non-pregnant group (8.26 m/s(2)). The right renal volume of the PIH group (132.76 cm(3)) was significantly higher that of the pregnant, normotensive group (125.29 cm(3)) and healthy, non-pregnant group (91.66 cm(3)). The same pattern was observed in the left renal volume which was 168.78 cm(3), 164.95 cm(3) and 113.80 cm(3) in the study groups, respectively.

CONCLUSION

Renal Doppler ultrasound is clinically relevant in the diagnosis and follow-up of renal complications in patients with pregnancy-induced hypertension.

Hemodynamic changes of renal main arteries in pregnancy-induced hypertension

OBJECTIVE

To detect Doppler ultrasonographic velocimetry alterations of renal main arteries in pregnancy-induced hypertension (PIH).

STUDY DESIGN

The peak systolic and end-diastolic velocities (Vs, Vd), resistivity and pulsatility indices (RI, PI), systolic/diastolic ratio (S/D ratio), acceleration time (AT) and systolic acceleration (SA) of renal main arteries were obtained in 17 PIH women and 15 age- and gestation week-matched normal pregnant (NP) women. The data between the two groups were compared with unpaired student's t-test.

RESULTS

The AT was much longer and SA much lower in PIH than those in NP, while no significant differences were found in Vs, Vd, RI, PI and S/D ratio.

CONCLUSIONS

AT and SA could be better used than Vs, Vd, RI, PI or S/D for detection of hemodynamic changes of renal arteries in patients with PIH. It may also imply that larger arteries proximal to the renal main artery be significantly affected.

Placental dysfunction in Suramin-treated rats – a new model for pre-eclampsia

Impaired placentation and oxidative stress are proposed to play major roles in the pathogenesis of placental dysfunction and pre-eclampsia. This study was carried out to evaluate if inhibited angiogenesis by Suramin injections in early pregnancy may cause a condition resembling pre-eclampsia in rats. Rats of two different Sprague-Dawley strains, U and H, were given intraperitoneal injections of Suramin or saline in early pregnancy. The outcome of pregnancy was evaluated on gestational day 20. Suramin injections caused increased blood pressure and decreased renal blood flow in the U rats. In both rat strains Suramin decreased the placental blood flow and caused fetal growth retardation. In both strains the placental concentration of the isoprostane 8-epi-PGF2alpha was increased, indicating oxidative stress. The serum concentration of Endothelin-1 was increased in the U rats. The U strain had a lower basal placental blood flow, and the effects of Suramin were more pronounced in this strain. We conclude, that Suramin injections to pregnant rats cause a state of placental insufficiency, which partly resembles human pre-eclampsia. The induction of this condition is at least partly mediated by oxidative stress, and is subject to varied genetic susceptibility.

Reproducibility of pulsed Doppler measurements of the maternal renal circulation in normal pregnancies and those with pregnancy-induced hypertension

OBJECTIVE

To assess the inter- and intraobserver reproducibilities of pulsed Doppler measurements of the maternal renal circulation in normal pregnancies and those affected by pregnancy-induced hypertension.

MATERIALS AND METHODS

Color and pulsed Doppler ultrasound was used to measure acceleration time and resistance index in the renal segmental and interlobar arteries. For the investigation of interobserver reproducibility, two sonographers performed measurements blindly in six normal pregnant women and 14 women with pregnancy-induced hypertension between 28 and 36 weeks' gestation. A second group of 10 patients between 30 and 35 weeks' gestation were examined by one sonographer to assess the level of intraobserver reproducibility of measurements. For each patient in this group, the flow waveform was measured three times in succession. Calculations of the intraclass correlation coefficient Ri were used to determine the level of reproducibility.

RESULTS

The interobserver Ri and intraobserver Ri for acceleration time in the segmental artery were 0.95 and 0.96 and for the interlobar artery they were 0.97 and 0.98, respectively. For the resistance index, these values were 0.01 and 0.01 in the segmental artery and 0.52 and 0.29 in the interlobar artery.

CONCLUSION

Both the inter- and intraobserver reproducibility of acceleration time measurements in the renal segmental and interlobar arteries were clinically acceptable but the equivalent reproducibilities of resistance index measurements were poor.