Vein Blood Velocity Research Articles

Impact of splenectomy on the hepatic hemodynamics in patients received liver transplantation

To investigate the changes of hepatic hemodynamics in patients with splenectomy plus living donor liver transplantation (LDLT). The data of 66 patients received LDLT from August 2006 to March 2009 were analyzed retrospectively:22 cases received splenectomy with LDLT (splenectomy group) and aged (45 ± 11) years. Forty-four comparable cases received LDLT only in the mean time were selected as control group and aged (44 ± 10) years. Comparative analysis was performed between the two groups with respect to the changes of hepatic hemodynamics after transplantation. Blood velocity in portal vein in control group and splenectomy group at 1 day before and after the transplantation were (12 ± 2) cm/s vs. (11 ± 3) cm/s, (35 ± 18) cm/s vs. (32 ± 17) cm/s, respectively. Postoperative blood velocity in portal vein in both groups increased significantly than the preoperative level (P < 0.05). Blood flow velocity in right hepatic vein in both groups at 1 week after the treatment were (44 ± 18) cm/s and (31 ± 15) cm/s (P < 0.05), respectively. Blood flow velocity in hepatic artery in both groups 2 weeks after the operation were (18 ± 8) cm/s vs. (26 ± 7) cm/s (P < 0.05) and resistance coefficient of hepatic artery were 0.66 ± 0.13 vs. 0.57 ± 0.12 (P < 0.05), respectively. Hepatic hemodynamics in patients received LDLT plus splenectomy is superior to that in patients received LDLT only.

CILIORETINAL ARTERIES IN DIABETIC EYES ARE ASSOCIATED WITH INCREASED RETINAL BLOOD FLOW VELOCITY AND OCCURRENCE OF DIABETIC MACULAR EDEMA

The main purpose was to investigate the relationship between occurrence of cilioretinal arteries and macular edema in diabetic eyes in terms of retinal blood flow characteristics revealed by the Retinal Function Imager (RFI). Other standard imaging techniques such as fundus photography, fluorescein angiography, and spectral-domain optical coherence tomography/scanning laser ophthalmoscopy were also used along with the RFI. The additional purpose was to look for the evidence of cilioretinal-retinal collaterals using the RFI. Patients with a diagnosis of diabetic retinopathy were included. All patients underwent fundus photography, fluorescein angiography, spectral-domain optical coherence tomography, and imaging using RFI. The presence of cilioretinal artery (CilRA) was recognized using color/red-free fundus photographs, fluorescein angiography, and RFI. There were two groups according to the presence (CilRA group) or absence (NoCilRA group) of cilioretinal artery or arteries in the study eye. Thirty-nine eyes with diabetic retinopathy were included. Cilioretinal artery was identified in 15 eyes (38%). In the CilRA group, spectral-domain optical coherence tomography evidence of macular edema was observed in 13 of 15 eyes (87%), whereas in the NoCilRA group, macular edema was observed on spectral-domain optical coherence tomography in 7 of 24 eyes (29%). Mean blood flow velocities in retinal arteries and veins were significantly higher in diabetic eyes with cilioretinal artery (P = 0.04 and P = 0.005, respectively). Mean blood velocity in cilioretinal arteries was significantly higher in comparison with the mean arterial blood velocity (P = 0.03). In the CilRA group, cilioretinal-retinal collaterals, assessed by RFI, were detected in 4 of 15 eyes (27%) with cilioretinal arteries. In the NoCilRA group, mean blood velocity in retinal veins was significantly higher in eyes with macular edema in comparison with those without macular edema (P = 0.03). Using the RFI in conjunction with standard fundus imaging techniques, the presence of cilioretinal artery in diabetic eyes was found to be associated with increased retinal blood flow velocity and increased occurrence of diabetic macular edema. The occurrence of cilioretinal-retinal collaterals was also noted; however, the pathophysiologic significance of this finding requires further investigation.

Measurements of blood flow velocity in human retinal veins using laser speckle flowgraphy system

We measured the blood flow velocity in human retinal veins using a laser speckle flowgraphy system. This system consists of a fundus camera, a diode laser, an image sensor and a personal computer system. The fundus is illuminated with a diode laser through a fundus camera and the laser speckle pattern is imaged onto the area sensor. From the time change of contrast of speckle pattern, normalized blur (NB) value, a quantitative index of tissue blood velocity, was calculated by means of a logistic board, and two-dimensional distribution of NB in the measurement field was displayed in a color display. In the in vitro experiment, the NB obtained from the blood flow in a glass capillary tube was correlated with the diameter of the tube, background NB value and the blood flow rate actually measured. In the in vivo experiment, the blood velocity in human retinal veins of approximately 50 microns in diameter was estimated in 16 normal eyes using nomograms based on the results of the in vitro experiment. Velocity averaged 11.1 +/- 0.6 mm/ sec (mean +/- standard deviation, n = 16) in retinal veins of 53 +/- 6 microns in diameter and the reproducibility index of the in vivo measurements was 2.5 +/- 0.9%.

Fetal breathing is associated with increased umbilical blood flow

In humans, fetal breathing movements affect blood velocities in the umbilical vein and artery, but it is not known whether fetal respiratory activity is associated with increased fetal blood flow through the placenta. We therefore tested this hypothesis in the present study. One-hundred and ten women with low-risk singleton pregnancies were each examined three times by ultrasound during the second half of pregnancy. Fetal heart rate, umbilical artery blood velocity, umbilical vein diameter and blood velocity, and umbilical blood flow at the placental end were determined during fetal rest and fetal respiratory movements. Based on 330 observations obtained during fetal rest or breathing activity, no difference was found in the mean fetal heart rate (beats per minute (bpm)) during rest compared with breathing (142 bpm vs. 142 bpm, respectively). Although fetal breathing affected the umbilical artery waveform, there was no difference in the mean time-averaged maximum velocity between rest and breathing: 26.6 (95% CI, 25.1-28.3) cm/s vs. 28.9 (95% CI, 27.2-30.7) cm/s, respectively. The umbilical vein was 27% greater in cross-sectional area and the blood velocity 9% higher during breathing, resulting in a 42% increase in mean umbilical blood flow: 121.8 (95% CI, 109.5-135.0) mL/min at rest vs. 173.0 (95% CI, 158.0-188.6) mL/min during breathing. Venous velocity was calculated from recordings of mean duration 3.7 s at rest and 6.2 s of respiratory activity. Gestational age did not influence the relationship. Fetal breathing is associated with increased umbilical blood flow during the second half of pregnancy. Umbilical vein distension during breathing suggests active endocrine regulation.

One versus Two Venous Anastomoses in Microvascular Free Flap Surgery

The authors' goal was to determine whether one or two venous anastomoses results in superior blood flow through microvascular free flaps. During flap harvest, blood velocity was measured in each of two venae comitantes using Doppler ultrasonography. Next, one of the two veins was occluded with a microvascular clamp and blood velocity was measured in the open vein. The clamp was then removed and placed on the other vein, and blood velocity was measured in the first vein. The pedicle was divided and microvascular anastomosis of either one or two veins was performed. Venous blood velocity was then compared between flaps with one versus two venous anastomoses. Eighty-one free flaps were performed. Before pedicle division, the peak venous blood velocity in each of the two venae comitantes averaged 6.3±4.8 cm/second. When one of the veins was occluded, the peak venous blood velocity increased to 19.5±17.3 cm/second (p<0.00001). One venous anastomosis was performed in 69 flaps and two venous anastomoses were performed in 12 flaps. The mean blood velocity in flaps in which one venous anastomosis was performed was greater than the mean blood velocity in either vein when two venous anastomoses were performed (13.1±7.3 cm/second versus 7.5±4.3 cm/second, respectively; p=0.001). When one vena comitans is occluded, blood velocity in the second vena comitans increases significantly. Venous blood velocity is significantly greater after a single venous anastomosis than in either of two veins when two venous anastomoses are performed. These results argue against routinely performing two venous anastomoses.

Evolution of the mammary capillary network and carbonic anhydrase activity throughout lactation and during somatotropin treatment in goats

During the normal course of lactation, mammary metabolic activity and blood flow are closely correlated. Six lactating goats were used in this experiment to test the hypothesis that the capillary network and the capillary enzyme, carbonic anhydrase (CA; EC 4.2.1.1) are important regulatory factors involved in the coordination of mammary blood flow (MBF) and metabolic activity. Milk vein blood velocity was determined as a measure of MBF, and fine needle mammary biopsies were obtained at different time points during lactation and by the end of a 14-d bovine somatotropin (BST) treatment initiated 3 months post partum. In mammary sections, CA activity was determined histochemically and alveolar and capillary structures by image analyses upon azure blue staining. In early lactation, alveoli were large and surrounded by many small capillaries with high CA activity. As lactation progressed, capillaries almost tripled in size, whereas number of capillaries surrounding each alveolus decreased by 1/3, and CA activity more than halved. BST treatment did not affect capillary traits but increased number of alveoli in mammary sections, and BST thus appeared to be targeted mostly towards the mammary epithelial cell. Milk vein blood velocity decreased over the course of lactation, when capillary area markedly increased, suggesting that control of mammary blood perfusion is not at the level of the capillary itself, but at pre- or post-capillary sites. We suggest that the observed changes in capillary diameter and CA activity with progressing lactation contributes to reduce efficiency of nutrient and waste product exchange across the capillary-mammary epithelial cell barrier, and this could be an important factor in regulation of mammary (epithelial cell) metabolic activity and lactation performance.

Quantification of blood velocity and flow rates in the uterine vessels using echo planar imaging at 0.5 Tesla

To measure uterine artery and vein blood velocity and flow rate profiles using MRI during normal pregnancy. A two-shot velocity magnitude-encoded echo planar imaging (EPI) sequence is used at a magnetic field 0.5T. Data analysis procedures, necessary to overcome problems associated with low signal to noise ratio (SNR), and a spatial resolution comparable to the vessel size were used. The measured blood flow values averaged over nine volunteers for the mean velocity are 5.33 and 3.97 cm/s and for the unilateral flow rate are 203 and 274 mL/min (for the arteries and veins respectively). Values for the flow rate are consistent with ultrasound Doppler studies. Arterial velocity measurements are more pulsatile than venous ones and validation calculations performed on average velocity values would suggest that the nature of blood flow in the uterine vessels is laminar. This study presents the first report of noninvasive quantitative measurements of uterine artery and vein blood velocity and flow rate profiles using MRI during normal pregnancy. Consistent and reproducible measurements have been obtained by subject specific sequence optimization and data analysis procedures.

Effect of compression stockings on venous blood velocity and blood flow

The effects of graduated compression stockings (GCS) on venous blood velocity have not been established. In healthy subjects, most investigations showed no effect on blood velocity, but mixed results have been reported. In this investigation we to test the hypothesis that popliteal blood velocity is increased by properly fitted GCS. Time average peak velocity in the popliteal vein, as well as time average mean velocity, vein diameter and mean volumetric flow were measured by pulsed wave Doppler ultrasound in 25 healthy male volunteers without compression stockings and repeated with fitted thigh-length compression stockings. Measurements were obtained while supine and while sitting at rest and during ankle exercise. Thigh-length GCS did not increase popliteal vein blood velocity, diameter, or volumetric blood flow while supine or sitting, with or without ankle exercise.

Correlation between Retina Blood Flow Velocity Assessed by Retinal Function Imager and Retina Thickness Estimated by Scanning Laser Ophthalmoscopy/Optical Coherence Tomography

Purpose: The purpose of this study was to evaluate the correlation between the retinal blood flow (RBF) assessed by the retinal functional imager (RFI) and central macular thickness/volume assessed by a spectral scanning laser ophthalmoscopy/optical coherence tomography (SLO-OCT) system. Methods: Seventeen eyes of 14 consecutive patients with various ocular diseases were examined. Retinal blood circulation characteristics were measured using the RFI. Retinal thickness/volume parameters were obtained by SLO-OCT. Analysis of correlation between RBF velocity and SLO-OCT findings was performed. Results: The analysis of the correlation between RBF and central retinal thickness/volume (5 × 5 mm grid pattern) showed a strong correlation between the average venous RBF velocity and central retinal volume. A linear relationship between the retinal blood velocity in veins and center, middle ring, outer ring and total central squares of macular volume [correlation coefficient 0.86 (p = 0.00001); 0.89 (p = 0.000001); 0.82 (p = 0.0004); 0.85 (p = 0.00001), respectively] has been observed. Arterial blood flow velocity did not correlate with thickness and with central retinal volume. Conclusions: Venous RBF, analyzed by the RFI, significantly correlated with the volume of the central retina, measured by SLO-OCT. Venous blood velocity increased linearly with the increase in the central retinal volume. In this small study, assessment using the RFI provides useful information and may contribute to the further understanding of hemodynamics in the retina blood vessels. The RFI shows promise of being able to analyze retinal hemodynamics noninvasively and may contribute to the further understanding of the relationship between retinal thickening and function.

Fetal superior mesenteric artery: Longitudinal reference ranges and evidence of regulatory link to portal liver circulation

Objective To establish longitudinal reference ranges for the fetal superior mesenteric artery (SMA) flow velocity and pulsatility index (PI SMA). Also to examine the hemodynamic relationship to venous liver perfusion and umbilical flow distribution in the liver, to other splanchnic arteries, and more generally to the middle cerebral and umbilical artery. Methods Prospective longitudinal study of 161 low-risk pregnancies using Doppler recordings including the SMA, repeated on 3–5 occasions at 3–5 weekly intervals. Umbilical venous flow was estimated, blood velocity in the shunt ductus venosus represented umbilico-caval (i.e. porto-caval) pressure gradient, and left portal vein blood velocity represented umbilical distribution within the liver. The correlation between PI SMA and the splenic and hepatic artery PI were analysed (PI SA and PI HA), and the association to middle cerebral and umbilical artery PI (PI MCA and PI UA) assessed. Results Reference ranges for the SMA for gestational weeks 21–39 were based on 589 observations. Low impedance in the SMA (i.e. low PI SMA) was associated with low umbilical flow and porto-caval pressure gradient (i.e. < 10th centile), and high distribution of umbilical flow to the right lobe (i.e. left portal vein blood velocity > 90th centile). PI SMA correlated weakly with PI SA and PI HA ( r = 0.30, 95%CI 0.22–0.37, and r = 0.39, 95%CI 0.27–0.51, respectively). PI SMA was positively associated with PI MCA and PI UA. Conclusion We have provided longitudinal reference ranges for fetal SMA flow velocity and PI, and shown that the SMA, which perfuses the fetal gut, is also involved in the regulation of the liver perfusion.

Fetal celiac and splenic artery flow velocity and pulsatility index: longitudinal reference ranges and evidence for vasodilation at a low portocaval pressure gradient

To establish longitudinal reference ranges for the fetal celiac and splenic arteries flow velocity and pulsatility index (PI), and to determine their hemodynamic relationship to venous liver perfusion and distribution and to other essential arteries. This was a prospective longitudinal study of 161 low-risk pregnancies. Doppler recordings of the celiac and splenic arteries were made on three to five occasions at 3-5-week intervals to establish reference ranges for blood velocity and PI measurements. Peak systolic velocity in the ductus venosus, a shunt between the umbilical and inferior caval veins, was used to represent the umbilicocaval (i.e. portocaval) pressure gradient, and the left portal vein blood velocity represented the umbilical distribution to the right liver lobe. The correlations between the celiac, splenic and hepatic arteries were determined, and their association with the middle cerebral and umbilical artery PIs (MCA-PI and UA-PI) was assessed. Longitudinal reference ranges for the fetal celiac and splenic arteries were established based on 510 and 521 observations, respectively, during gestational weeks 21-39. Terms for calculating conditional reference ranges to be used for repeat observations are provided. Celiac and splenic artery PIs were low when portocaval pressure and umbilical supply to the right lobe were low (P < 0.0001). Their peak systolic velocity and PI were correlated (r = 0.7 (95% CI, 0.6-0.8) and r = 0.5 (95% CI, 0.3-0.6), respectively), while the PI of the hepatic artery correlated weakly with those of the celiac and splenic arteries. They were positively associated with the MCA-PI and UA-PI (P < 0.0001). We provide longitudinal reference ranges for the fetal celiac and splenic arteries Doppler measurements and show that they are involved in maintaining portal liver perfusion independently from the hepatic artery.

The Manifold Actions of Statins: Effects of Systemic Administration of Simvastatin on Retinal Circulation, by T Nagaoka, A Takahashi, E Sato, et al. Arch Ophthalmol 124:665–70, 2006

To investigate the effect of systemic administration of simvastatin on the retinal circulation. The effects of systemic administration of simvastatin on the retinal circulation after 90 minutes and after 7 days were studied in a placebo-controlled, double-masked, clinical trial among 12 healthy men. We used laser Doppler velocimetry to measure vessel diameter and blood velocity and calculated the blood flow in retinal arteries and veins. We also measured the intraocular pressure and the plasma nitrite/nitrate levels, the stable end products of nitric oxide metabolism. There were no significant changes in any retinal circulatory parameters at 90 minutes after administration of simvastatin. Daily administration of simvastatin for 7 days significantly increased blood velocity and blood flow in retinal arteries and veins but did not significantly change vessel diameter. The intraocular pressure significantly decreased at 90 minutes and at 7 days after administration of simvastatin. Simvastatin also significantly increased the plasma nitrite/nitrate levels. Simvastatin induced an increase in blood velocity and blood flow in retinal arteries and veins, increased the plasma nitrite/nitrate levels, and decreased the intraocular pressure, probably through the increase in nitric oxide.

Effect of Systemic Administration of Simvastatin on Retinal Circulation

To investigate the effect of systemic administration of simvastatin on the retinal circulation. The effects of systemic administration of simvastatin on the retinal circulation after 90 minutes and after 7 days were studied in a placebo-controlled, double-masked, clinical trial among 12 healthy men. We used laser Doppler velocimetry to measure vessel diameter and blood velocity and calculated the blood flow in retinal arteries and veins. We also measured the intraocular pressure and the plasma nitrite/nitrate levels, the stable end products of nitric oxide metabolism. There were no significant changes in any retinal circulatory parameters at 90 minutes after administration of simvastatin. Daily administration of simvastatin for 7 days significantly increased blood velocity and blood flow in retinal arteries and veins but did not significantly change vessel diameter. The intraocular pressure significantly decreased at 90 minutes and at 7 days after administration of simvastatin. Simvastatin also significantly increased the plasma nitrite/nitrate levels. Simvastatin induced an increase in blood velocity and blood flow in retinal arteries and veins, increased the plasma nitrite/nitrate levels, and decreased the intraocular pressure, probably through the increase in nitric oxide.

Development of Miniaturized Fiber-Optic Laser Doppler Velocimetry Sensor for Measurement of Local Blood Velocity (Measurement of Human Whole Blood Velocity in Modeled Blood Vessel Using Fiber-Optic Sensor Having Convex Lens-like Tip)

In order to measure local blood velocity in artery and vein, a miniaturized fiber-optic LDV sensor has been newly developed. In the present fiber-optic sensor, laser beam emitted from the fiber tip can be focused at any position from about 0.1 to 0.5 mm distant from the fiber tip, and moreover a stray light or an unfavorable reflected light inside the light transmission system is remarkably decreased. Consequently the present sensor has a sufficiently high signal-to-noise ratio, and is capable of measuring the local velocity in almost all semi-opaque and opaque fluids including blood. The sensor head, i.e. the optical fiber is incorporated into either a injection needle or a catheter tube. In the former case, it is inserted inclinatorily from the wall into the vessel, and is made a tilted scan across the vessel to measure a velocity distribution. In the latter case, it is kept parallel to the flow in the vessel. In all the flows of whole human blood, whole caprine blood and a RC-MAP (red cell / Mannitol-Adenine-Phosphate) of bovine, of which hematocrit is 69%, the volocity distribution across the vessel can be very accurately measured. The insertion angle of the fiber to the flow has a significant effect on the measurement accuracy, and the appropriate angle is about 100 degree in the injection needle type. In the catheter type, the insertion direction adverse to the flow is better than that parallel to the flow because of an effect of wake behind the fiber tip. The influence of light source, i.e. a He-Ne gas laser and a He-Ne laser diode on the measurement accuracy is small.

Mammary uptake and excretion of prostanoids in relation to mammary blood flow and milk yield during pregnancy-lactation and somatotropin treatment in dairy goats

Mammary arterious − venous differences (A − V) and excretion into milk of four prostanoids were related to changes in milk yield and milk vein blood velocity (MBV) in goats at different stages of pregnancy and lactation, and during somatotropin (ST) treatment in mid-lactation. Arterial concentrations and mammary A − V for the vasodilators prostacyclin (PGI 2) and prostaglandin (PG) E 2 (measured as 6-keto-PGF 1α and bicyclic PGE 2, respectively) decreased from late pregnancy to lactation. A − V were negatively correlated to MBV ( r = −0.32 to −0.34). Arterial concentrations of the vasoconstrictors PGF 2α and TXA 2 (measured as TXB 2) changed similarly, but no A − V across the mammary gland were found. The vasodilator to vasoconstrictor ratio in plasma was around 1:1, and in skimmed milk around 0.29–0.49 due to significantly higher TXB 2 levels in milk compared to plasma. Close linear correlations were established between milk yield and excretion of TXB 2 into milk ( r = 0.80, P < 0.001), and between MBV and PGE 2 excretion into milk ( r = 0.69, P < 0.001). ST treatment stimulated MBV and mammary prostanoid supply, and decreased prostanoid concentration in milk vein plasma. The high arterial levels of prostaglandins during pregnancy most likely reflected uterine synthesis. Our results support a role for PGI 2 and PGE 2 in local mammary blood flow regulation during lactation. Increased mammary uptake of these two prostanoids may be involved in the mammary blood flow response to ST. TXA 2 may be synthesized by mammary epithelial as well as vascular cells, and TXA 2 may be an important factor in regulation of mammary function.

Umbilical Artery N-Terminal Peptide of Proatrial Natriuretic Peptide in Hypertensive Pregnancies and Fetal Acidemia During Labor

In Brief Objective To assess the activity of the human fetal atrial natriuretic peptide system in hypertensive pregnancies with and without signs of increased fetal systemic venous pressure and in pregnancies complicated by fetal acidemia during labor. Methods Umbilical artery plasma N-terminal peptide of proatrial natriuretic peptide concentrations were measured in neonates by radioimmunoassay. The control group consisted of 50 neonates with uncomplicated gestation and labor. In group 1, there were 22 newborns of hypertensive pregnancies. Doppler ultrasonography showed abnormal umbilical artery blood velocity waveform in five cases and normal nonpulsatile umbilical vein blood velocity profile in every case. Group 2 consisted of five newborns of pregnancies complicated by maternal hypertensive disorder. Atrial pulsations in the umbilical vein and retrograde diastolic blood velocity pattern in the umbilical artery were detected in every case. Group 3 was composed of 27 newborns of uncomplicated pregnancies with fetal acidemia (pH 7.10 or less) during labor. Results In groups 1–3, N-terminal peptide of proatrial natriuretic peptide concentrations were higher (P < .001) than in the control group. In group 1, neonates with abnormal umbilical artery blood velocity pattern had higher N-terminal peptide of proatrial natriuretic peptide concentrations than neonates with normal umbilical artery Doppler findings (P < .006). N-terminal peptide of proatrial natriuretic peptide concentrations were higher in group 2 (P < .002) than in groups 1 and 3. Conclusion Maternal hypertensive disorder and fetal acidemia during labor stimulate fetal atrial natriuretic peptide production, which was greatest in fetuses with severe placental insufficiency and signs of congestive heart failure. Maternal hypertension and fetal acidemia during labor stimulate human fetal atrial natriuretic peptide production, which is highest in fetuses with severe placental insufficiency and congestive heart failure.

Umbilical artery N-terminal peptide of proatrial natriuretic peptide in hypertensive pregnancies and fetal acidemia during labor

Objective: To assess the activity of the human fetal atrial natriuretic peptide system in hypertensive pregnancies with and without signs of increased fetal systemic venous pressure and in pregnancies complicated by fetal acidemia during labor. Methods: Umbilical artery plasma N-terminal peptide of proatrial natriuretic peptide concentrations were measured in neonates by radioimmunoassay. The control group consisted of 50 neonates with uncomplicated gestation and labor. In group 1, there were 22 newborns of hypertensive pregnancies. Doppler ultrasonography showed abnormal umbilical artery blood velocity waveform in five cases and normal nonpulsatile umbilical vein blood velocity profile in every case. Group 2 consisted of five newborns of pregnancies complicated by maternal hypertensive disorder. Atrial pulsations in the umbilical vein and retrograde diastolic blood velocity pattern in the umbilical artery were detected in every case. Group 3 was composed of 27 newborns of uncomplicated pregnancies with fetal acidemia (pH 7.10 or less) during labor. Results: In groups 1–3, N-terminal peptide of proatrial natriuretic peptide concentrations were higher ( P < .001) than in the control group. In group 1, neonates with abnormal umbilical artery blood velocity pattern had higher N-terminal peptide of proatrial natriuretic peptide concentrations than neonates with normal umbilical artery Doppler findings ( P < .006). N-terminal peptide of proatrial natriuretic peptide concentrations were higher in group 2 ( P < .002) than in groups 1 and 3. Conclusion: Maternal hypertensive disorder and fetal acidemia during labor stimulate fetal atrial natriuretic peptide production, which was greatest in fetuses with severe placental insufficiency and signs of congestive heart failure.

F56Blood velocity in fetal Galen vein and outcome of pregnancy

BackgroundPulsating blood velocity in the umbilical vein is an indicator of fetal compromise with poor outcome. Blood velocity in the fetal vein of Galen is normally even and without fluctuation. The propose of this study was to establish whether blood flow velocity pulsations in the Galen vein seen in high‐risk pregnancies were also related to adverse outcome of pregnancy.MethodsThe vein of Galen was located by color Doppler ultrasound in 102 pregnancies complicated by pregnancy‐induced hypertension and blood velocity recorded by pulsed Doppler within 2 days of delivery. The presence of blood velocity pulsation's was noted and correlated to perinatal outcome, including emergency operative intervention and/or neonatal distress. Umbilical artery and venous, uterine and middle cerebral artery blood velocity was also recorded at the same time.ResultsPulsating blood velocity in the vein of galen was found in 68 cases and in the umbilical vein in 21. Venous pulsations were highly significantly related to adverse outcome of pregnancy. Pulsations in the Galen vein were three times more frequent than in the umbilical vein, suggesting that it appears earlier than in the umbilical vein. In all the 7 perinatal deaths there were pulsations in the Galen vein. Signs of brain sparing in the middle cerebral artery were seen in only 32 fetuses.ConclusionVenous pulsations in the umbilical and Galen vein were both significantly correlated to adverse outcome of high‐risk pregnancy. Pulsations in the vein of Galen seem to occur earlier than in the umbilical vein, which might be helpful when deciding the timing of delivery of a high‐risk case with minimal neonatal morbidity.

WS17‐08Fetal biochemical markers in severe placental insufficiency – comparison with fetal Doppler findings

BackgroundThe aims of this study were to assess the activity of the human fetal atrial natriuretic peptide system in hypertensive pregnancies with and without signs of increased fetal systemic venous pressure and to investigate the association between severe placental insufficiency and fetal myocardial cell destruction.MethodControl group consisted of 50 newborns with uncomplicated pregnancy and labor. In group 1, 22 newborns after hypertensive pregnancies were included. Doppler ultrasonography revealed abnormal umbilical artery (UA) blood velocity waveform in five cases, and normal nonpulsatile umbilical vein (UV) blood velocity profile in every case. Group 2 consisted of five newborns after pregnancies complicated by maternal hypertensive disorder. Atrial pulsations in the UV and retrograde diastolic blood velocity pattern in the UA were detected in every case. Immediately after birth blood samples were collected from the UA and plasma N‐terminal peptide of proatrial natriuretic peptide (NT‐proANP) and serum cardiac specific troponin‐T concentrations were measured.ResultsIn group 1, nt‐proANP concentrations were higher (P &lt; 0.001) than in the control group. In group 1, newborns with abnormal UA blood velocity pattern had higher (P &lt; 0.006) NT‐proANP concentrations than newborns with normal UA Doppler findings. Troponin‐T concentrations in group 1 did not differ from the control group. In group 2, NT‐proANP (P &lt; 0.002) and troponin‐T (P &lt; 0.0001) concentrations were higher than in the control group and study group 1.ConclusionMaternal hypertensive disorder stimulates fetal atrial natriuretic peptide production, being greatest in fetuses with severe placental insufficiency and a rise in systemic venous pressure. These fetuses also have evidence of myocardial cell destruction.

Human retinal hemodynamics following administration of 5-isosorbide mononitrate

Purpose. The purpose of this randomized double-masked cross-over study was to determine the effects of 20 mg of 5-isosorbide mononitrate (ISMO) on the retinal hemodynamics of young healthy subjects. Methods. Monochromatic fundus photography and bidirectional laser Doppler velocimetry (BLDV) were used to determine vascular diameters (D), and blood velocity (V max) and flow (Q) in retinal veins, respectively. The diameter of the vein [D (vein) ] at the same location where BLDV measurements were made, and the diameter of a neighboring artery [D (art) ], were determined from the fundus photographs. Measurements were carried out one and three hours after ISMO dosing, on twelve and six subjects, respectively. Mean blood pressure (BP m) and intraocular pressure (IOP) were also monitored, and ocular perfusion pressure (PP) was calculated. Results are expressed in percentage changes (± the standard error of the mean). Results. On average, we observed a moderate increase of Q one hour after ISMO dosing (+8.2 ± 5.4%), but not after placebo (+2.7 ± 1.6%). This effect of ISMO, which displayed remarkable interindividual variability (95% confidence interval: -3.9%, +20.4%), did not attain statistical significance. D (vein) and D (art) were not appreciably affected. No effect was observed three hours after either ISMO or placebo dosing. PP was reduced one hour following ISMO administration, mainly as a function of reduced BP m, although this variation was not statistically significant. IOP did not change appreciably throughout the duration of the study. Conclusions. Our findings suggest that, in contrast to the optic nerve head, in which we previously documented consistent and significant increases in blood flow following ISMO administration at both one and three hours, retinal hemodynamics are not equally responsive to a single dose of ISMO at these time points. Marked interindividual variability to the effects of this long-acting nitric oxide donor was documented one hour after administration, but not at three hours. This study further suggests that distinct vascular tissues of the ocular microcirculation respond differently to identical pharmacological challenges.