Artery Diastolic Flow Research Articles

Machine Learning Quantification of Pulmonary Regurgitation Fraction from Echocardiography.

Assessment of pulmonary regurgitation (PR) guides treatment for patients with congenital heart disease. Quantitative assessment of PR fraction (PRF) by echocardiography is limited. Cardiac MRI (cMRI) is the reference-standard for PRF quantification. We created an algorithm to predict cMRI-quantified PRF from echocardiography using machine learning (ML). We retrospectively performed echocardiographic measurements paired to cMRI within 3months in patients with ≥ mild PR from 2009 to 2022. Model inputs were vena contracta ratio, PR index, PR pressure half-time, main and branch pulmonary artery diastolic flow reversal (BPAFR), and transannular patch repair. A gradient boosted trees ML algorithm was trained using k-fold cross-validation to predict cMRI PRF by phase contrast imaging as a continuous number and at > mild (PRF ≥ 20%) and severe (PRF ≥ 40%) thresholds. Regression performance was evaluated with mean absolute error (MAE), and at clinical thresholds with area-under-the-receiver-operating-characteristic curve (AUROC). Prediction accuracy was compared to historical clinician accuracy. We externally validated prior reported studies for comparison. We included 243 subjects (median age 21years, 58% repaired tetralogy of Fallot). The regression MAE = 7.0%. For prediction of > mild PR, AUROC = 0.96, but BPAFR alone outperformed the ML model (sensitivity 94%, specificity 97%). The ML model detection of severe PR had AUROC = 0.86, but in the subgroup with BPAFR, performance dropped (AUROC = 0.73). Accuracy between clinicians and the ML model was similar (70% vs. 69%). There was decrement in performance of prior reported algorithms on external validation in our dataset. A novel ML model for echocardiographic quantification of PRF outperforms prior studies and has comparable overall accuracy to clinicians. BPAFR is an excellent marker for > mild PRF, and has moderate capacity to detect severe PR, but more work is required to distinguish moderate from severe PR. Poor external validation of prior works highlights reproducibility challenges.

The High-Risk Profile of Selective Growth Restriction in Monochorionic Twin Pregnancies.

The present review aims to provide a critical appraisal of the sonographic diagnosis and follow-up and to evaluate the optimal clinical management of monochorionic twin pregnancies where one of the twins is complicated by selective fetal growth restriction (sFGR). The classification is based on the umbilical artery (UA) diastolic flow reflecting the outcome. If the sFGR twin has positive diastolic flow (Type I) then the prognosis is good, and it does not require close surveillance. Biweekly or weekly sonographic and Doppler surveillance and fetal monitoring are recommended strategies to detect unpredictable complications in type II and type III forms, which are defined by persistently absent/reverse end-diastolic flow (AREDF) or cyclically intermittent absent/reverse end-diastolic flow (iAREDF) in the umbilical waveforms, respectively. The latest forms are associated with an increased risk of unexpected fetal demise of the smaller twin and 10-20% risk of neurological injury in the larger twin in addition to the overall risk of prematurity. The clinical course can be affected by elective fetal therapy ('dichorinization' of the placenta with laser or selective fetal reduction) or elective delivery in the presence of severe fetal deterioration. The prediction of the clinical outcome in complicated cases of type II and III sFGR cases remains elusive. Novel routines in fetal and placental scans in order to predict neurological impairments and unexpected fetal death to optimize the delivery time-point are needed.

Reversed diastolic flow in a renal transplant due to ureteric obstruction from intraluminal blood clot

AbstractReversal of arterial diastolic flow is commonly considered a sign of transplant renal vein thrombosis until proven otherwise, with the differential including acute rejection, acute tubular necrosis, and perirenal hematoma. We discuss a case of a patient who presented with decreased urine output on the second postoperative day following living unrelated kidney transplantation. Doppler ultrasound was performed and demonstrated reversal of diastolic flow in the transplant renal artery. Prompt surgical exploration revealed intraluminal blood clot obstructing the ureter. To our knowledge, this is the first reported case of reversed diastolic flow secondary to ureteral obstruction by an intraluminal blood clot.

Utility of quantitative magnetic resonance angiography and non-invasive optimal vessel analysis for identification of complications and long-term hemodynamic changes in post-pipeline embolization patients.

Quantitative magnetic resonance angiography and non-invasive optimal vessel analysis serve as powerful tools to collect and analyze hemodynamic data from pipeline embolization patients. At our institution, patients receive post-embolization quantitative magnetic resonance angiography within 24 h of treatment and within 6 months for follow-up to evaluate pipeline patency. Here, we aim to elucidate the long-term hemodynamic changes following pipeline embolization device placement and report two cases in which in-stent stenosis was detected. Medical records of patients who underwent pipeline embolization device placement for an internal carotid artery aneurysm between 2017 and 2019 were reviewed. Patients who received post-procedure NOVA and follow-up NOVA were included in the study (n = 32). Location and size of aneurysm, number of pipeline embolization device deployed, and complications were collected along with the non-invasive optimal vessel analysis report (flow volume rate (ml/min), mean, systolic, and diastolic flow velocities (cm/s), and vessel diameter (mm)). Internal carotid artery vessel flow rate was measured proximal to the pipeline embolization device. Derivations of hemodynamic parameters (pulsatility index, Lindegaard ratio, and wall shear stress) were calculated. The middle cerebral artery mean and diastolic flow velocities were significantly lower on the follow-up NOVA compared to the post-procedure NOVA. Moreover, follow-up NOVA demonstrated lower middle cerebral artery wall shear stress on the side with flow diversion compared to the post-procedure NOVA. In-stent stenosis, requiring intervention, was detected in two patients on follow-up NOVA. One patient had a successful balloon angioplasty of the stented internal carotid artery that resolved her stenosis. However, the second patient developed progressive stenosis and expired despite intervention. Long-term hemodynamic adaptations post-pipeline embolization device demonstrate decreased wall shear stress and decreased mean and diastolic flow velocities in the distal middle cerebral artery, which suggest decreasing velocity of blood flow with endothelialization of the device. Furthermore, follow-up NOVA is a useful tool for detecting potential flow-related complications such as in-stent stenosis.

Size of Patent Ductus Arteriosus and Echocardiographic Markers of Shunt Volume in Preterm Infants Based on Postnatal Age.

Objective: This study was conducted in order to compare the strength of correlation between echocardiographic markers of shunt volume and patent ductus arteriosus (PDA) diameter based on postnatal age.Methods: This retrospective study focused on preterm infants (aged <32 weeks of gestation) admitted to the Neonatal Intensive Care Unit of Korea University Ansan Hospital, between April 2014 and December 2017, who studied serial targeted neonatal echocardiography (TNE) for PDA during hospitalization. The association between echocardiographic characteristics and duct size was divided into the following days: within 3 days (very early, VE), 4–7 days after birth (early, E), and after 8 days of birth (late, L).Results: We found 113 assessments conducted on 57 infants in the VE period, 92 assessments on 40 infants in the E period, and 342 assessments on 37 infants in the L period. Median gestational age and birth weight were 28+2 weeks of gestation and 1,115 g, respectively. In the univariate regression analysis, we found a statistically significant correlation between PDA diameter and all TNE markers in the E and L days, but not in the VE period. Only ductal velocity [coefficient of determination (R2) = 0.224], antegrade left pulmonary artery diastolic flow velocity (R2 = 0.165), left ventricular output (LVO)/superior vena cava (SVC) flow ratio (R2 = 0.048), and E/A wave ratio (R2 = 0.092) showed weak correlations with PDA diameter in the VE period. The slopes of the regressions showed significant changes based on postnatal age in the maximum ductal velocity, left atrium/aorta ratio, LVO/SVC flow ratio, and LVO.Conclusions: It is difficult to predict the echocardiographic markers of shunt volume based on the PDA diameter in preterm infants younger than 4 days. A better understanding of the changes in the hemodynamic consequences of PDA based on postnatal age is needed when considering treatment.

Fetal Sacrococcygeal Teratoma and the Development of Hydrops.

* Abbreviations: CVO: : combined ventricular output DVP: : deepest vertical pocket EXIT: : ex utero intrapartum therapy FTC: : Fetal Treatment Center MCA: : middle cerebral artery MRI: : magnetic resonance imaging NTD: : neural tube defect PPROM: : preterm premature rupture of membranes RFA: : radiofrequency ablation SCT: : sacrococcygeal teratoma TFR: : tumor volume–to–fetal weight ratio UCSF: : University of California, San Francisco A large sacrococcygeal teratoma (SCT) was detected on routine 18-week fetal ultrasonography in a 26-year-old, gravida 2, para 0 woman. She had a history of Helicobacter pylori gastric infection and an ovarian cyst, in addition to a previous spontaneous abortion at 15 weeks’ gestation. This pregnancy had been uncomplicated and prenatal laboratory testing was unremarkable. She was evaluated at an outside fetal care center at 21 weeks’ gestation. At that time, the fetal SCT measured 5.9×5.3 cm of mixed solid and cystic components, about 30% to 50% of the fetal size. Given the size of the SCT, with interval growth from initial diagnosis, she was referred to the University of California, San Francisco (UCSF) Fetal Treatment Center (FTC) to discuss the options for fetal surgical intervention. The woman was seen at the UCSF FTC at 23 weeks’ gestation. Imaging at that time included fetal ultrasonography and fetal echocardiography. Ultrasonography (Fig 1) demonstrated a largely exterior SCT with a small, presacral component. The tumor was largely solid with small cystic components and classified as an SCT type 1 lesion. The dimensions were 11.6×10.5×9.6 cm with an estimated volume of 611 mL, about 87% of the fetal size. There was no evidence of polyhydramnios, with the deepest vertical pocket (DVP) at 7.7 cm. Fetal echocardiography showed normal cardiac anatomy with significant dilation of the inferior vena cava and mild cardiomegaly with a cardiothoracic ratio of 0.36. The combined ventricular output (CVO) was significantly elevated at 817 mL/kg per minute (upper limit of normal is 500 mL/kg per minute). Diastolic flow velocity in the umbilical artery (systolic-to-diastolic velocity ratio of 6.2) was low, possibly secondary to a “steal phenomenon” to the tumor. The middle cerebral artery (MCA) diastolic flow velocity was also low, suggestive of cerebral vasodilation to maintain cerebral blood flow (brain-sparing). …

Comparison of bilateral and unilateral umbilical artery diastolic blood flow abnormalities in monochorionic diamniotic twin pregnancies

Aim: Our study aimed to clarify the prognosis of bilateral and unilateral umbilical artery end-diastolic blood flow abnormalities (BFAs) in monochorionic diamniotic twin pregnancies.Methods: Monochorionic diamniotic twin pregnancies were classified into bilateral (group 1), unilateral (group 2), and no (group 3) umbilical artery end-diastolic BFAs. After the usual obstetric management, short- and long-term prognoses were analyzed.Results: A total of 171 monochorionic diamniotic twins were analyzed and classified into group 1 (13 twins, 7.6%), 2 (12 twins, 7.0%), and 3 (146 twins, 85.4%). Gestational age at delivery was significantly lower in group 1 than in groups 2 and 3 (median, 29.3, 35.6, and 35.6 weeks, respectively; p < .01 and p < .001). The survival rate of fetuses with BFAs was significantly lower in group 1 than in group 2 (23.0% [3/13] versus 100% [12/12]; p < .001). However, the survival rate of the co-twin was not significantly different between groups 1 and 2 (84.6% [11/13] versus 100% [12/12]; p = .48). The survival rate of both fetuses was significantly lower in group 1 than in groups 2 and 3 (53.8% [14/26], 100% [24/24], and 98.6% [288/292], respectively; both p < .001). In cases with fetal therapy, the survival rate of both fetuses tended to be lower in group 1 than in group 2 (44.4% [8/18] versus 83.3% [10/12]; p = .05). In cases without fetal therapy, the gestational age at delivery tended to lower in group 1 than in group 2 and was significantly lower than in group 3 (median, 29.1, 35.6, 35.6 weeks, respectively; p = .05 and p < .05). The survival rate of fetuses with BFA tended to be lower in group 1 than in group 2 (50.0% [2/4] versus 100% [12/12]; p = .05). The survival rate of the co-twin was not significantly different between groups 1 and 2 (100% [4/4] versus 100% [12/12]; p = 1). The survival rate of both fetuses tended to be lower in group 1 than in group 2 and was significantly lower than in group 3 (75% [6/8], 100% [24/24], and 99.2% [278/280], respectively; p = .05 and p < .01).Conclusions: In monochorionic diamniotic twin pregnancies, bilateral umbilical artery end-diastolic BFAs demonstrated a poor prognosis. However, unilateral abnormalities exhibited a good prognosis similar to that in twins with normal umbilical artery blood flow. If such abnormalities are detected during a routine checkup, the umbilical artery pulse wave on the other side should be examined.

Amnioinfusion for variable decelerations caused by umbilical cord compression without oligohydramnios but with the sandwich sign as an early marker of deterioration

We report prophylactic amnioinfusion (AI) for variable decelerations in umbilical cord compression without oligohydramnios as an early sign of deterioration. We performed a transabdominal AI in cases without oligohydramnios using the ultrasonography findings of umbilical cord compression (i.e. sandwich sign [SWS]) and variable decelerations (VD) in a foetal heart rate. Thirteen cases and 21 AIs were analysed. Nine (69%) cases were of a foetal growth restriction and 4 (31%) had umbilical hyper-coiled cords. VD frequency (p < .0001), umbilical artery pulsatility index (PI) (p < .01) and ductus venous PI (0.66 vs. 0.48; p < .05) significantly decreased, and an umbilical venous (UV) flow volume (121 vs. 197 ml/min/kg; p < .05) significantly increased after AI. The umbilical artery diastolic blood flow abnormalities and UV pulsation improved. In conclusion, AI improves the umbilical cord compression even without oligohydramnios. The SWS is an important marker of deterioration to severe oligohydramnios and latent foetal damage.IMPACT STATEMENTWhat is already known on this subject? Antepartum variable decelerations due to umbilical cord compression are significantly associated with the deceleration in labour. In particular, foetal hypoxia leads to other adverse events such as foetal distress, hypoxic-ischemic encephalopathy, and pulmonary arterial hypertension after birth. Amnioinfusion has been shown to be effective in patients who also have oligohydramnios.What do the results of this study add? Amnioinfusion may be effective in the cases with ultrasonography findings of umbilical cord compression (i.e. sandwich sign) and in cases with variable decelerations in foetal heart rate, but without oligohydramnios.What are the implications of these findings for clinical practice and/or further research? Amnioinfusion may be helpful to prevent adverse events including oligohydramnios and anhydroamnios.

Decreased Blood Flow in the Testis: Is it Testicular Torsion?

The absence of blood flow in the testis on ultrasound examination is the gold standard for diagnosis of testicular torsion. This imaging finding is seen in the vast majority of patients with testicular torsion, except in patients with partial torsion. Patients with partial testicular torsion may have reversal of arterial diastolic flow on spectral Doppler, decreased amplitude of the spectral Doppler waveform (parvus tardus wave), or monophasic waveforms. However, it is important to consider that not all absence of blood flow or reversal of diastolic flow in testis represents testicular torsion, as other conditions may have a similar appearance, including rare detection of such a pattern in normal asymptomatic patients. Conditions that commonly mimic testicular torsion include incarcerated inguinal hernias and complications following hernia repair,thrombotic phenomena, vasculitis, complicated epididymo-orchitis, asymptomatic variants, and technical limitations of ultrasonography. It is important for a practicing radiologist to be familiar with such cases to avoid unnecessary surgical interventions.We present a pictorial essay of cases in which the absence of testicular blood flow on color flow Doppler or abnormal waveforms on spectral Doppler are identified, without the presence of testicular torsion.

The clinical curative effect of Tianshu capsule in the treatment of migraine and its influence on vascular endothelial function and hemodynamics

Objective To investigate the clinical efficacy of Tianshu capsule in the treatment of migraine and its influence on vascular endothelial function, hemodynamics. Methods 80 patients with migraine from October 2014 to October 2015 in our hospital were selected as the research subjects, and according to the different treatment methods, they were divided into control group and observation group.The control group was treated with oral flunarizine hydrochloride capsules, the observation group was given Tianshu capsule on the basis of the treatment of the control group.The blood dynamics of the two groups before and after treatment and the clinical curative effect of the patients[the middle cerebral artery (MCA), anterior cerebral artery (ACA), Fu (PCA) after artery peak systolic velocity (Vs) and diastolic peak flow velocity (Vd) index, endothelin (ET) index]were observed. Results The curative effect of two groups was significantly improved compared with before treatment, the total effective rate of observation group (97.50%) was significantly higher than the control group (75.00%)(χ2=8.54, P<0.05). The related indices of hemodynamics and endothelium were lower than before treatment, and after treatment, Vs of MCA, ACA, PCA in the observation group were (105.02±1.12)cm/s, (80.22±1.10)cm/s, (60.34±1.20)cm/s, Vd of MCA, ACA, PCA in the observation group were (35.22±1.13)cm/s, (40.33±1.21)cm/s, (21.23±1.12)cm/s, which were significantly lower than those in the control group[Vs of MCA, ACA, PCA: (120.10±1.13)cm/s, (95.33±1.12)cm/s, (80.21±1.13)cm/s; Vd of MCA, ACA, PCA: (42.33±1.10)cm/s, (50.23±1.10)cm/s, (30.21±1.10)cm/s](t=25.46, 25.76, 33.38, 12.30, 17.04, 15.55, all P<0.05). Conclusion The curative effect of Tianshu capsule in the treatment of migraine was improved in patients with cerebral blood flow velocity and vascular diastolic function, and is worthy of promotion. Key words: Migraine; Tianshu capsule; Clinical curative effect; Vascular endothelial function; Hemodynamics

Cross-Sectional Associations of Flow Reversal, Vascular Function, and Arterial Stiffness in the Framingham Heart Study.

Experimental studies link oscillatory flow accompanied by flow reversal to impaired endothelial cell function. The relation of flow reversal with vascular function and arterial stiffness remains incompletely defined. We measured brachial diastolic flow patterns along with vasodilator function in addition to tonometry-based central and peripheral arterial stiffness in 5708 participants (age 47±13 years, 53% women) in the Framingham Heart Study Offspring and Third Generation cohorts. Brachial artery diastolic flow reversal was present in 35% of the participants. In multivariable regression models, the presence of flow reversal was associated with lower flow-mediated dilation (3.9±0.2 versus 5.0±0.2%; P<0.0001) and reactive hyperemic flow velocity (50±0.99 versus 57±0.93 cm/s; P<0.0001). The presence of flow reversal (compared with absence) was associated with higher central aortic stiffness (carotid-femoral pulse wave velocity 9.3±0.1 versus 8.9±0.1 m/s), lower muscular artery stiffness (carotid-radial pulse wave velocity 9.6±0.1 versus 9.8±0.1 m/s), and higher forearm vascular resistance (5.32±0.03 versus 4.66±0.02 log dyne/s/cm5; P<0.0001). The relations of diastolic flow velocity with flow-mediated dilation, aortic stiffness, and forearm vascular resistance were nonlinear, with a steeper decline in vascular function associated with increasing magnitude of flow reversal. In our large, community-based sample, brachial artery flow reversal was common and associated with impaired vasodilator function and higher aortic stiffness. Our findings are consistent with the concept that flow reversal may contribute to vascular dysfunction.

Reversed Diastolic Flow in Page Kidney Following Native Kidney Biopsy

Page kidney phenomenon occurs due to external compression of a kidney by either subcapsular or perinephric hematoma, tumor, lymphocele, or urinoma. This article describes a case of reversed diastolic arterial flow on Doppler insonation in a Page kidney due to external compression as a consequence of native kidney biopsy-induced perinephric hematoma. Reversed diastolic arterial flow has already been reported in Page kidney in renal allografts; however, we are not aware of any report of such a finding in a native kidney. This report highlights the importance of being aware of the possible occurrence of the reversion of the diastolic flow in Doppler sonography in Page kidney, even though it is rare. Moreover, this case illustrates the short but severe impact of Page kidney on renal function and suggests that a conservative approach is an effective treatment option even in a moderate to severe perinephric hematoma.

OP.5D.01] INHIBITON OF TNF-ALPHA SIGNALLING USING ETANERCEPT IMPROVES DEFICIENT UTERINE ARTERY REMODELLING AND PREGNANCY OUTCOME IN THE STROKE PRONE SPONTANEOUSLY HYPERTENSIVE RAT

Objective: Impaired vascular remodelling has been extensively studied in pre-eclampsia but little is known about adaptation of the cardiovascular (CV) system to pregnancy in women with chronic hypertension. We have previously characterised the stroke prone spontaneously hypertensive rat (SHRSP) as a model of deficient uterine artery remodelling and identified an increase in pro-inflammatory TNF α relative to the normotensive WKY strain during pregnancy. Design and method: SHRSP were treated with etanercept (0.8 mg/kg) or vehicle at gestational day (GD) 0, 6, 12 and 18. Animals were sacrificed at GD18. SHRSP, SHRSP treated with etanercept (ETN) and WKY (n=6) were used for vascular studies. An independent set of animals (n = 6) were used for flow cytometry analysis. Results: Etanercept significantly reduced systolic blood pressure in the SHRSP after GD 10 (δSBP GD 10–21 SHRSP 12.0 ± 4.17 vs. ETN 25.8 ± 4.27 mmHg; p < 0.05). Characterisation of uteroplacental blood flow using Doppler showed that etanercept significantly increased uterine artery diastolic blood flow and significantly reduced resistance index relative to SHRSP (SHRSP 0.79 ± 0.02 vs. ETN 0.61 ± 0.02 resistance index; p < 0.01). Analysis of GD18 uterine arteries using pressure and wire myography showed that etanercept did not change the size of the uterine arteries; but significantly reduced uterine artery contractile ability (SHRSP 57.3 ± 8.75 vs. ETN 35.2 ± 2.19 kPa; p < 0.01) and increased carbachol response (SHRSP 13.8 ± 3.8 % vs. ETN 40.1 ± 3.25 %; p < 0.05). Etanercept significantly increased litter size in the SHRSP (SHRSP 7.80 ± 0.44 vs. ETN 12.75 ± 0.94 fetuses), reduced resorption frequency (SHRSP 66.7% vs. ETN 25.0% dams with resorption) and decreased premature glycogen cell loss from the placenta. We sought to identify the source of excess TNFα in the SHRSP. Inflammatory natural killer (NK) cells (CD3- CD161+) were significantly increased in the SHRSP relative to the WKY in the placenta (WKY 11.6 ± 2.39 vs. SHRSP 659.8 ± 201.2 cells/mg; p < 0.01). Etanercept significantly reduced the number of NK cells in the placenta of the SHRSP (SHRSP 659.8 ± 201.2 vs. ETN 148.0 ± 12.62 cells/mg; p < 0.01). Conclusions: Etanercept improves abnormal uterine artery function in the SHRSP with beneficial effects on pregnancy. Excess TNFα production in this model may come from increased inflammatory NK cells.

OP.3C.05] CHARACTERISTICS OF CEREBRAL HEMODYNAMICS AND CAROTID STIFFNESS IN PATIENTS WITH ISCHEMIC LEUKOARAIOSIS AND NEW ULTRASOUND INDICES OF ISCHEMIC LEUKOARAIOSIS

Objective: Leukoaraiosis (ILA) is believed to be ischaemic in origin due its association with cerebrovascular risk factors and similar location as lacunar infarctions. Its pathophysiology is not well understood and its diagnosis is still based on magnetic resonance imaging (MRI) as well as exclusion of other causes of white matter hyperintensities (WMH). So far there are no known confirming or screening diagnostic tests of ILA. Ultrasound studies have recently shown increased large artery stiffness, increased cerebrovascular resistance and lower cerebral blood flow in ILA patients. Increased arterial stiffness and decreased blood flow could have a synergistic effect and their ratio could be a useful diagnostic index of ILA. Design and method: We used Trans Cerebral Doppler sonography (TCD) and carotid duplex ultrasound to compeare cerebral blood flow and carotid stiffness in 53 ILA patients to 40 risk factor matched controls. The ILA diagnosis was based on head MRI and exclusion of other causes of WMH. Middle cerebral artery (MCA) systolic, diastolic and mean blood flow velocities (v-MCAs, v-MCAd, v-MCAm) and resistance indices (RI, PI) were determined. Carotid stiffness was accessed by pulse wave velocityβ (PWVβ, m/s), pressure–strain elasticity modulus (Ep, kPa) and β index. In addition we introduced new ILA indices (ILAi) that are rations of carotid stiffness parameters and MCA mean blood flow velocity. The diagnostic significance of ILAi for the prediction of ILA was analysed. Results: We found significantly lower diastolic, systolic and mean MCA blood flow velocities and increased carotid stiffness in the ILA group (p < 0,05). Higher pulsatility and resistivity indices of MCA were found in the ILA group, but they did not reached statistical significance. All the ILAi were significantly higher in the ILA group, the most significant was PWVβ/v-ACMm (p = 0.003). All ILAi were allso significantly associated with ILA and were sensitive and specific for predicting ILA (p < 0.05). Conclusions: MCA blood flow velocities are lower and carotid stiffness increased in ILA patients compared to risk factors matched controls. The combination of lower velocities and increased carotid stiffness represented as ILA indices could have a potential diagnostic value for ILA.

Major contribution of central pulmonary reservoir discharge to increased pulmonary arterial diastolic blood flow after birth in near-term lambs.

Recent fetal lamb data have suggested that the pulmonary trunk (PT) region displays a reservoir function and that a pharmacologically induced fall in pulmonary vascular resistance (PVR) increases and redistributes diastolic discharge from this central pulmonary reservoir toward the lungs, thereby producing a positive diastolic offset in the pulmonary arterial (PA) blood flow profile. As a similar offset in PA flow characteristically occurs after birth, this study tested the hypotheses that 1) central pulmonary reservoir discharge is both redistributed toward the lungs and increased in magnitude during the birth transition and 2) discharge from this reservoir constitutes a major component of increased PA diastolic blood flow after birth. Six anesthetized near-term fetal lambs were instrumented with PT, ductal and left PA transit-time flow probes, and aortic, PT and left atrial catheters. Hemodynamic data were recorded in fetuses and at regular intervals during 2-h mechanical ventilation following cesarean section delivery. Diastolic PA blood flow rose from near zero in fetuses to 468 ± 188 ml/min by 15 min (P < 0.001). Central pulmonary reservoir discharge in fetuses (99 ± 44 ml/min) passed primarily right-to-left across the ductus. However, this reservoir discharge redistributed entirely to the lungs by 1 min after birth, and then doubled to a peak of 214 ± 167 ml/min at 15 min (P < 0.001). Reservoir discharge subsequently stabilized at 151 ± 60 ml/min at 30-120 min, which comprised ∼50% of diastolic and ∼20% of mean PA blood flow. These findings suggest that enhanced diastolic central pulmonary reservoir discharge plays a major role in supporting an increased pulmonary perfusion after birth.

Human embryonic cardiovascular function.

This review presents an overview of descriptive knowledge on human embryonic cardiovascular physiology mostly based on noninvasive assessment by Doppler ultrasonography. Our objective was to identify and analyze published studies on embryonic cardiovascular function, and summarize available knowledge in this field. Citations related to human embryonic cardiovascular function were searched in PubMed, EMBASE, CINAHL and Web of Science using keywords and MeSH terms without any time limitation. The search was restricted to English language articles. Abstracts were screened and full texts of relevant articles were obtained. All articles that reported on physiological aspects of human embryonic cardiovascular function were included. Studies reporting on cardiovascular function after 10 weeks of gestation were excluded. Data were synthesized and presented narratively. We identified 10 studies that had evaluated cardiovascular function and/or hemodynamics in human embryos at ≤10 weeks of gestation. All of these reported only certain aspects of embryonic cardiovascular function. Embryonic heart rate is associated significantly with gestational age and increases from 6 to 10 weeks of gestation. Cardiac inflow is monophasic during the embryonic period and atria appear to generate higher force during contraction compared with ventricles. Both ventricular inflow and outflow velocities increase with advancing gestation, whereas the Tei index decreases significantly. During the embryonic period, placental blood flow increases with gestation, but absent umbilical artery diastolic flow and umbilical venous pulsations are normal phenomena. There are important differences in normal cardiovascular function between the embryonic and fetal stages of human in utero development.

US Findings in Patients at Risk for Pancreas Transplant Failure.

Purpose To determine if ultrasonographic (US) findings, including Doppler US findings, are associated with subsequent pancreas transplant failure. Materials and Methods A cohort of adult patients who underwent pancreas transplantation at a tertiary institution over the course of 10 years (from 2003 to 2012) was retrospectively evaluated for failure, which was defined as return to insulin therapy or surgical graft removal. The institutional review board provided a waiver of informed consent. All US images obtained within the 1st postoperative year were reviewed for three findings: arterial flow (presence or absence of intraparenchymal forward diastole flow), splenic vein thrombus, and edema. These findings were correlated with pancreas graft failure within 1-year after surgery by using Cox proportional hazards models and hazard ratios. Results A total of 228 transplants were included (mean patient age, 41.6 years; range, 19-57 years; 122 men, 106 women). Absent or reversed arterial diastolic flow was identified in nine of 20 failed transplants (sensitivity, 45%; 95% confidence interval [CI]: 23, 68) and in 15 of 208 transplants that survived (specificity, 93% [193 of 208]; 95% CI: 89, 96). The Cox proportional hazard ratio was 6.2 (95% CI: 3.1, 12.4). Splenic vein thrombus was identified in 10 of 20 failed transplants (sensitivity, 50%; 95% CI: 27, 73) and in 25 of 208 transplants that survived (specificity, 88% [183 of 208]; 95% CI: 83, 92). The Cox proportional hazard ratio was 4.2 (95% CI: 2.4, 7.4). Edema had the lowest specificity (Cox proportional hazard ratio, 2.0; 95% CI: 1.3, 2.9). In the multivariate analysis, only absent or reversed arterial diastolic flow remained significantly associated with transplant failure (adjusted hazard ratio, 3.6; 95% CI: 1.0, 12.8; P = .045). Conclusion Absent or reversed diastolic arterial Doppler flow has a stronger association with transplant failure than does splenic vein thrombus or edema. (©) RSNA, 2016.

Hemodynamically significant ductus arteriosus:a new targeted approach

Debate on hemodynamically significant ductusarteriosus (hsDA) in premature infants remains unresolved. The association between patent ductus arteriosus (PDA) and the most adverse outcomes and comorbidities in preterms (peri-intraventricular haemorrhage, necrotizing enterocolitis, chronic lung disease, pulmonary haemorrhage and mortality) has led to the integration of ductal closure into neonatal intensive care. The recent theory that describes PDA as “an innocent bystander” is supported by the lack of evidence of significant benefits on long-term outcomes with therapeutic interventions. So, the causal relationship between PDA and comorbidities is questioned. Moreover, PDA can close spontaneously in a significant proportion of preterms[1]. Both the traditional assumption that all PDA are pathological and the most recent theory in favor of a conservative attitudeare oversimplifications[2]. The current management of PDA does not take into account the wide range of effects attributable to a ductal shunt. A more logical approach should considerthe ductus as a clinical continuum, from thephysiological PDA to the pathological hsDA. Placingthe patient in the spectrum of “ductal disease” seems to be possible through a continuous evaluation of the hemodynamic and clinical consequences of ductal patency[3]. The current definition of an hsDA is almost entirely based on size[4]. However, the magnitude of transductal shunt relates not only to the transductal diameter, but also to the pulmonary and systemic vascular resistance and to the compensatory ability of the immature myocardium[3]. New echocardiography markers have been evaluated to estimate the impact of transductal flow on both pulmonary over circulation (left atrial/aortic ratio, anterograde pulmonary artery diastolic flow) and systemic blood flow (retrograde diastolic flow in descending aorta, left ventricular output/superior vena cava flow ratio)[5]. The possibility to evaluate flows in the middle cerebral artery, renaland superior mesenteric artery with Doppler ultrasound, allows anearly and plausible detection of regional hypoperfusion due to the “ductal steal”[3]. Other technologies that enable direct measurement of tissue oxygenation, such as Near Infrared Spectroscopy (NIRS), may also be useful to unveil the hemodynamic effects of PDA[6,7]. We are becoming increasingly aware of the role of patient's characteristics (such as genetic profile[8], BNP levels[9], antioxidant status[10]) in PDA evolution. According to the current understanding, it seems appropriate to proposea more tailored approach to the management of PDA in preterms, based on the integration between clinical and hemodynamic status.

Middle cerebral arterial flow changes on transcranial color and spectral Doppler sonography in patients with increased intracranial pressure.

Intracranial pressure usually increases after severe brain injury. However, a method for noninvasive evaluation of intracranial pressure is still lacking. The purpose of this study was to explore the potential role of transcranial color Doppler sonography in assessing intracranial pressure by observing the middle cerebral artery blood flow parameters in patients with increased intracranial pressure of varying etiology. The hemodynamic changes in the middle cerebral artery in patients with varying degrees of increased intracranial pressure were investigated by transcranial color Doppler sonography in 93 patients who had emergency surgery for brain injury. Middle cerebral artery Doppler flow spectra changed regularly as intracranial pressure increased. The pulsatility index (PI) and resistive index (RI) had a significantly positive correlation with intracranial pressure (r = 0.90 and 0.89, respectively; P< .001), whereas the middle cerebral artery diastolic velocity showed a significant negative correlation with intracranial pressure (r = -0.52; P< .01). A receiver operating characteristic curve showed that the RI and PI cutoff values were 0.705 and 1.335, respectively, for predicting increased intracranial pressure, with sensitivity of 0.885 and specificity of 0.970. In addition to the PI and RI, middle cerebral artery diastolic flow velocity measurement by transcranial color Doppler sonography may also be a useful variable for evaluating intracranial pressure in patients with acute brain injury.

Echocardiography parameters of clinically normal adult captive chimpanzees (Pan troglodytes)

To generate reference ranges for echocardiographic variables in clinically normal adult chimpanzees (Pan troglodytes). Retrospective cohort study. 88 clinically normal adult chimpanzees. Echocardiographic data obtained between 2002 and 2011 from chimpanzees at the Alamogordo Primate Facility were reviewed (263 echocardiograms obtained from 158 individuals). Data from clinically normal individuals (33 females and 55 males) were analyzed. Basic cardiac parameters measured in all individuals included aortic root diameter and left atrial diameter in the short and long axis during diastole. Left ventricular measurements included left ventricular internal diameter in systole and diastole and diastolic septal and posterior wall thickness. The E point to septal separation was also measured. Spectral Doppler measurements included the peak flow velocity of the pulmonary artery and aorta and diastolic transmitral flow. The presence of arrhythmias was also noted. Standard echocardiographic findings for a large group of adult female and male chimpanzees were obtained. Female and male chimpanzees were grouped by age in 10-year blocks, and echocardiographic findings were analyzed statistically by 10-year block. In male chimpanzees, cardiac arrhythmias were noted to increase with age. Cardiovascular disease is an important cause of morbidity and death in captive chimpanzees; however, basic echocardiographic measurements from a large cohort of clinically normal animals have not previously been reported. The number of animals in the present study was insufficient to generate reference ranges; however, data from a large cohort of clinically normal animals are presented. This information will be useful for veterinarians working in clinical and research settings with this species.