Blood Flow In Descending Aorta Research Articles

Echocardiographic Comparison of Left Ventricular Systolic Function and Aortic Blood Flow Velocimetry in Children with Ventricular Septal Defect.

The assessments of left ventricular (LV) longitudinal systolic dynamics in children with ventricular septal defect (VSD) have achieved a major milestone in the evaluation of LV systolic function. This study aims to evaluate the LV function, LV mass (LVM), and the descending aorta blood flow in children with VSD compared to that obtained in age and sex-matched controls. The mean LVM of the control, 113.5 ± 123.9 was higher than that of those who had VSD, 75.8 ± 83.9, and the difference in mean was found to be statistically significant (Mann-Whitney U = 2.322, P = 0.022). The mean EF of the control, 67.9 ± 10.3 was comparable to that of those with VSD, 65.6 ± 13.9, (Student's t = 1.223, P = 0.223). Similarly, the mean descending aorta blood flow of control, 1.6 ± 2.2 was comparable to that of those with VSD, 3.9 ± 16.1, (Mann-Whitney U = 1.002, P = 0.321). There was a very weak positive correlation between LVM and descending aorta blood flow among the subjects (n = 85, r = 0.117, P = 0.425). There was a very weak negative correlation between LVM and descending aorta blood flow among control. (n = 85, r = -0.065, P = 0.609). The LVM among children with VSD is lower than controls but there is no difference between LV function in subjects and controls. There is a linear increase of LVM with descending aorta blood flow.

Fetal Cardiac Functional Assessment by Fetal Heart Magnetic Resonance Imaging

We attempted to evaluate fetal cardiac activity of congenital heart disease (CHD) and normal heart fetuses by magnetic resonance imaging (MRI). We evaluated the fetal cardiac functional assessment and the blood flow of descending aorta at 34 weeks' gestation or more by MRI and compared the results with ultrasonography findings. We measured 6 normal heart fetuses and 14 CHD fetuses. The ejection fraction (EF) and descending aorta blood flow in the CHD group were 76.4% ± 11.9%, 687.5 ± 303.8 mL/min by ultrasonography and 48.3% ± 7.1%, 711.4 ± 273.1 mL/min by MRI; those in the normal group were 66.9% ± 12.2%, 898.1 ± 245.9 mL/min by ultrasonography and 51.3% ± 4.2%, 911.9 ± 223.1 mL/min by MRI. There was no significant difference in descending aorta blood flow measurements between ultrasonography and MRI, but the EF showed a significant between-group difference. In the normal group, the variation of EF and blood flow measured by MRI was significantly smaller compared with those of ultrasonography.

Thoracic stent graft sizing for endovascular repair in Stanford type B aortic dissection

Endovascular treatment for Stanford type B aortic dissection uses thoracic aortic stent-graft system, which consists of covered stent and delivery system. The system is different in the configuration of the stent, the delivery system and the mode of release. The principle of endovascular treatment for Stanford type B aortic dissection is different from aortic aneurysm, so there are differences in stent selection. On the basis of preoperative assessment and measurement, it is suggested that the proximal diameter oversize of the stent is 0 to 5%, at 160 to 200 millimeters in length. The distal end of the stent should pass through the bend of the descending aorta to accommodate the descending aorta blood flow, and the oversize is 0. The postoperative complications and mortality including reverse dissection of proximal part and intima rupture of distal part induced by the stent will be effectively reduced with familiarity with the characteristics of stent-graft, understanding of the possible side effects of stent-graft, combining with the actual conditions and mastering the above principles.

Descending Aorta Blood Flow Characteristics before the Development of Necrotizing Enterocolitis in Preterm Neonates

Descending Aorta Blood Flow Characteristics before the Development of Necrotizing Enterocolitis in Preterm Neonates

Evaluation of the predictive value of fetal Doppler ultrasound for neonatal outcome from the 36th week of pregnancy.

Background:Early prediction of adverse neonatal outcome would be possible by Doppler impedance indices of middle cerebral artery (MCA), umbilical artery (UmA), and descending aortal artery (AO) that result in decrease neonatal morbidity and mortality rate. The aim of the present study was a determination of optimal value for the ratio of MCA to descending aorta blood flow (MCA/AO) impedance indices and its comparison with the ratio of MCA to UmA (MCA/UmA) impedance indices and their relationship with neonatal outcome.Materials and Methods:This was a prospective cohort study on 212 pregnant women with gestational age 36 weeks or more, in three hospitals in Tehran, from April 2012 to April 2013. We investigated AO, MCA, and UmA impedance indices Doppler ultrasound every 2 weeks till delivery. The mother was monitored for adverse pregnancy outcome (hypertension [HTN], fetal growth retardation, and other maternal complications) then infant birth weight, cord blood of pH, and Neonatal Intensive Care Unit (NICU) admission during the first 24 h after delivery were assessed. Finally, we investigated relationships between Doppler indices and neonatal outcomes include neonatal body weight (NBW), cord blood of pH, and NICU admission.Results:MCA/AO resistance index (RI) and MCA/AO pulsatile index (PI) showed an area under the receiver operating characteristics curve (area under the curve) of 0.905 (95% confidence interval (CI): 0.850, 0.959) and 0.818 (95% CI: 0.679, 0.956), respectively. The cutoff values for pH (≥7.2 vs. <7.2) based on MCA/AO RI and MCA/AO PI indices were 0.951 (sensitivity, 80% and specificity, 86%) and 0.853 (sensitivity, 91% and specificity, 83%), respectively. The cutoff value for NBW (≥2500 vs. <2500 g) based on MCA/UmA PI index was 1.467 (sensitivity, 73% and specificity, 63%). The cutoff value of NICU admission of child based on MCA/AO PI index was 1.114 (sensitivity, 73% and specificity, 54%).Conclusion:In the end of third-trimester pregnancies with the assessment of MCA and AO artery Doppler ultrasonography, it is possible to prevent many cases of neonatal acidosis caused by prenatal asphyxia as well as inappropriate interventions which are applied on mother. If MCA/AO PI was <0.85, the fetus needs to be evaluated further because it is at risk for acidosis.

Impacts of therapeutic hypothermia on cardiovascular hemodynamics in newborns with hypoxic-ischemic encephalopathy: a case control study using echocardiography

Purpose: The effects of therapeutic hypothermia (TH) on hemodynamics in newborns with hypoxic-ischemic encephalopathy (HIE) were evaluated.Materials and methods: Thirty-two neonates (gestational age, 39.4 ± 1.3 weeks) who had TH for HIE and echocardiographic hemodynamic assessments during TH and post-TH period were studied. Gestational-age-matched 34 healthy neonates were enrolled for comparison.Results: During TH, patients had significantly decreased left ventricular cardiac output (LVCO), descending aorta blood flow (DABF), and DABF/LVCO ratio, and increased resistive index of DA compared to controls. Upper body blood flow (UBBF) remained unchanged but UBBF/LVCO ratio significantly increased during TH. Urine output decreased significantly during TH and increased after rewarming, and showed significant positive correlation with DABF/LVCO ratio. Sixteen patients (50%) showed hypoxic-ischemic (HI) lesions on brain magnetic resonance imaging (MRI) and had significantly increased UBBF/LVCO ratio during TH compared to patients without HI lesions. Patients with UBBF/LVCO ratio >55% had significantly higher risk of having HI lesions on brain MRI (odds ratio 13.0; 95% CI, 2.4–70.2).Conclusions: Decrease in cardiac output and descending aorta blood flow, and preferential cerebral redistribution of cardiac output along with an increase in systemic peripheral vascular resistance may affect systemic organ perfusion and cerebral metabolism.

Emergency and sub-emergency transcatheter closure of patent ductus arteriosus in infants

Objective To explore the effects and follow-up findings of emergency and sub-emergency transcatheter closure of patent ductus arteriosus (PDA) in infants. Methods A retrospective study was performed to analyze the effects, complications, immediate and mid-term follow-up outcomes in 12 infants with PDA from Guangzhou Women and Children's Medical Center between March 2008 and April 2014 in order to evaluate the efficacy and safety of transcatheter closure of PDA in infants.All cases were diagnosed preoperatively as pneumonia, and 10 cases had congestive heart failure.Pulmonary symptoms showed no obvious change after regular internal medicine therapies. Results Twelve devices (100%) were successfully implanted.Echocardiogram was performed 3 days after the procedures and showed no residual shunt in any case.Left ventricular end-diastolic dimension[(31.3±5.4) mm], left atrial diameter[(18.2±3.4) mm], left ventricular ejection fraction(LVEF)[(56.8±8.7)%], pulmonary artery systolic pressure and mitral regurgitation were decreased or alleviated in contrast with those before the procedures(all P 0.05). Left pulmonary artery blood flow velocity was increased in 3 cases.The maximal descending aorta blood flow velocity was 1.9 m/s and 2.4 m/s respectively in 2 cases, blood flow velocity of left pulmonary artery and descending aorta were blow 2.3 m/s, pressure gradient was less than 2.9 kPa in 23-28 months after the procedure and no patient received any other intervention. Conclusions Emergency and sub-emergency transcat-heter closure of PDA in infants is safe and feasible, but long-term follow-up is needed in patients with increased left pulmonary artery blood flow velocity and/or descending aorta blood flow velocity. Key words: Patent ductus arteriosus; Interventional therapy; Emergency and sub-emergency; Infant

Uterine Infusion of Melatonin or Melatonin Receptor Antagonist Alters Ovine Feto-Placental Hemodynamics During Midgestation1

Dietary melatonin supplementation from mid- to late gestation increases umbilical artery blood flow and causes disproportionate fetal growth. Melatonin receptors have been described throughout the cardiovascular system; however, there is a paucity of data on the function of placental melatonin receptors. The objectives of the current experiment were to determine fetal descending aorta blood flow, umbilical artery blood flow, and placental and fetal development following a 4-wk uterine infusion of melatonin (MEL), melatonin receptor 1 and 2 antagonist (luzindole; LUZ), or vehicle (CON) from Day 62 to Day 90 of gestation. After 4 wk of infusion, umbilical artery blood flow and umbilical artery blood flow relative to placentome weight were increased (P < 0.05) in MEL- versus CON- and LUZ-infused dams. Fetal descending aorta blood flow was increased (P < 0.05) in MEL- versus CON- and LUZ-infused dams, while fetal descending aorta blood flow relative to fetal weight was increased in MEL- versus CON-infused dams and decreased in LUZ- versus CON-infused dams. Following the 4-wk infusion, we observed an increase in placental efficiency (fetal-placentome weight ratio) in MEL- versus LUZ-infused dams. The increase in umbilical artery blood flow due to chronic uterine melatonin infusion is potentiated by an increased fetal cardiac output through the descending aorta. Moreover, melatonin receptor antagonism decreased fetal descending aorta blood flow relative to fetal weight. Therefore, melatonin receptor activation may partially mediate the observed increase in fetal blood flow following dietary melatonin supplementation.

Doppler manifestations of ductal steal: role in decision making

Patent ductus arteriosus in extremely premature babies is associated with major neonatal morbidities such as necrotizing enterocolitis and intraventricular haemorrhage. Altered systemic blood flow and end-organ hypoperfusion are known associates of a haemodynamically significant ductus arteriosus where descending aorta blood flow profiles may reveal abnormal diastolic retrograde flow. A preterm neonate was noted to have a large symptomatic patent ductus arteriosus with reversal of diastolic flow in the superior mesenteric vessels. Treatment with indomethacin led to ductal closure and concomitant restoration of diastolic flow and resolution of symptoms. Doppler studies of systemic vessels may help improve our understanding of the systemic impact of a haemodynamically significant ductus arteriosus.

Spectral Doppler waveforms in systemic arteries and physiological significance of a patent ductus arteriosus

Patent ductus arteriosus in extremely premature babies is associated with major neonatal morbidities, such as necrotizing enterocolitis and intraventricular hemorrhage. This may be attributable, at least in part, to systemic hypoperfusion secondary to ductal steal. A hemodynamically significant ductus arteriosus (HSDA) is known to be associated with altered systemic blood flow and end-organ hypoperfusion. Although descending aorta blood flow profiles may show abnormal diastolic retrograde flow, Doppler studies of blood flow in the systemic arteries may help improve our understanding of the relationship of a HSDA with these morbidities. In this article, we discuss aspects of diastolic blood flow reversal in the systemic arteries in premature infants with a hemodynamically significant duct. Whether these hemodynamic effects are significant enough to form the basis for initiating treatment is still unclear; these should form the basis for prospective studies.

Role of hypervolemic hemodilution in focal cerebral ischemia of rats

This study was designed to better define a protocol for hypervolemic hemodilution in acute cerebral ischemia and investigate the mechanism of action of this therapy. Anesthetized rats ( n = 40) were subjected to 6 h of middle cerebral artery (MCA) occlusion. At 45 min after MCA occlusion, each rat received one of the following treatment modalities: (1) control, (2) isovolemic hemodilution, (3) hypervolemic nonhemodilution (whole blood), (4) hypervolemic hemodilution (normal saline), and (5) hypervolemic hemodilution (hetastarch). Local cerebral blood flow (CBF) was determined with hydrogen clearance technique, and cardiac output was assessed by measuring the descending aorta blood flow (DAF). Infarction volume was estimated by 2,3,5-triphenyltetrazolium chloride staining method. Hetastarch infusion increased both DAF and local CBF more than the other treatments, by 98% and by 89%, respectively. Hetastarch also reduced infarction volume the most to 71 ± 19 mm 3 ( p < 0.01 versus control 117 ± 32 mm 3). A significant correlation between percent (%) changes in local CBF and % changes in DAF existed in ischemic brain regions, and the hetastarch infusion improved local CBF more prominently in profoundly ischemic regions in contrast to isovolemic hemodilution. These data demonstrated the superiority of hypervolemic hemodilution with hetastarch as compared to other similar treatment modalities for acute cerebral ischemia, and indicate that cardiac output augmentation may be more responsible than decreased blood viscosity for the beneficial effect of hypervolemic hemodilution on local CBF in profoundly ischemic regions, as such ischemic brain tissue can severely lose its regulatory control of CBF to alterations in cardiac output.

Antenatal fetal blood flow in the descending aorta and in the umbilical vein and their ratio in normal pregnancy

One hundred and sixty sequential measurements of umbilical vein blood flow (UVBF) and descending aorta blood flow (DABF) in normal fetuses were performed in utero by the duplex real-time ultrasound and pulsed Doppler technique. Throughout pregnancy from 26 to 41 weeks the blood flow velocity of the umbilical vein (UV) and the descending aorta (DA) remained relatively constant, while the diameter of UV and DA, UVBF and DABF increased with advancing gestational age. Moreover, the UVBF-to-DABF ratio was nearly constant, with a mean value of 64% from 26 weeks onwards. The DABF-to-abdominal area (DABF-to-AA) ratio was constant throughout pregnancy, with a mean value of 7.0 ml/min/cm 2. We call these two constants the umbilical-aortic index and descending-aortic index. These relationships may be of help in the diagnosis of intrauterine growth retardation and other fetal disorders.

Blood flow in the fetal descending aorta.

Doppler estimation of the blood flow in the descending aorta of the fetus and waveform analysis of the maximum aortic velocity provide valuable information on fetal circulation. When estimating fetal aortic flow, it is important to consider possible sources of error; even when recording the maximum aortic velocity for waveform analysis, to obtain reproducible results it is important to use a low high-pass filter, a well-defined angle of insonation, and a standardized site of measurement and to avoid periods of fetal breathing and activity. In normal pregnancy the time-averaged mean velocity in the descending aorta is stable throughout the third trimester. The weight-related flow is stable until 37 weeks, after which it falls slightly. The placental proportion of the flow in the thoracic descending aorta decreases toward term. In the aorta of normal fetuses there is positive flow throughout the whole heart cycle, which is due to the low vascular resistance in the placental circulation. The waveform of the aortic velocity can be characterized by the PI, which is stable during the last trimester of gestation. Caution is required when interpreting changes in the aortic PI, as it is not only affected by the peripheral resistance but also by the heart performance. Furthermore, PI is related to fetal heart rate. Near term different values of PI are found in different fetal behavioral states. In fetuses with retarded growth and in fetuses at distress, characteristic changes of the aortic velocity waveform have been reported by several researchers: the end-diastolic velocity diminishes and disappears, and in extreme cases a brief reversal of flow in diastole was observed. Consequently, the PI increases in such cases. The absence of the end-diastolic aortic velocity can easily be determined and is the best indicator of fetal status: in fetuses with absent end-diastolic velocity the incidence of perinatal mortality and morbidity is significantly higher than in fetuses with positive flow throughout the cycle. In pregnancies with hypertension or diabetes mellitus, normal aortic flow has been reported, as long as the fetuses were not growth retarded. In cases of severe Rh-isoimmunization, the mean aortic velocity correlates with fetal hematocrit. In hypoxic fetuses the mean velocity was reported to correlate with the degree of hypoxia, hypercarbia, and acidosis.(ABSTRACT TRUNCATED AT 400 WORDS)