Doppler Flow Velocity Research Articles

Abstract 4116141: Von Willebrand Factor Inhibition by BB-031 Prevents and Thrombolyses Clots in a Murine Model of Venous Thrombosis

Introduction: Venous thromboembolism (VTE) manifesting as deep vein thrombosis and pulmonary embolus results in ~300,000 US deaths annually. Risk factors include obesity and current therapy limitations leave ~ 50% of patients with no effective treatment. Circulating von Willebrand Factor (VWF) levels portend poor clinical outcomes. BB-031, an aptamer-based VWF inhibitor with prophylactic and arterial thrombolytic efficacy may translate to VTE. Methods: Jugular vein occlusion (JVO) was induced by FeCl 3 either before or after intravenous treatment in 14 week old male and female C57/BL6 wild type (WT) or male diet-induced obese (DIO) mice. 5.0 mg/kg BB-031 was administered as a bolus, 10.0 mg/kg rtPA with 10% bolus and remaining 90% over 60 minutes, 400 U heparin as a bolus, or vehicle. Doppler jugular vein flow velocity was recorded from baseline to determine patency 30 minutes after injury. Thrombolytic clots were stabilized for 20 minutes. Results: Prophylactic mice occluded ~20 minutes after FeCl 3 application with rtPA=18.32 +/- 6.54 min, heparin 17.14 +/- 8.53 min, and vehicle 17.29 +/- 7.26 min. Thrombosis did not occur with BB-031 treatment (n=4-12/group). Treatment after JVO resulted in no difference compared to vehicle in male WT mice, but BB-031-treated WT females resulted in 76.09% recanalization 35 minutes after occlusion compared to rtPA (9.64%, p<0.0001), heparin (30.95%, p=0.7306), or vehicle (22.07%, p<0.0001), (n=5/group). Male DIO mice significantly reperfused with BB-031 (100%) vs rtPA (10.52%), heparin (4.54%), and vehicle (22.50%), p<0.0001, (n=4-6/group). Conclusion: VWF inhibition by BB-031 maintains patency in a VTE murine model offering future therapeutic alternatives.

Abstract 4120805: Comparison of Thermodilution and Doppler Flow Velocity Derived Indexes of Coronary Physiology using Intracoronary Adenosine in Patients with Angina and Unobstructed Coronary Arteries (ANOCA)

Introduction: Patients with angina but unobstructed coronaries (ANOCA) represent a diagnostic and therapeutic challenge. Current Guidelines recommend invasive testing using acetylcholine and adenosine for evaluation of coronary vasomotor disorders. However, there is a broad variability among the different measurement techniques. Purpose: To assess the differences of bolus thermodilution versus Doppler flow velocity derived indexes of coronary physiology using intracoronary adenosine in patients with ANOCA. Methods: A total of 162 patients (61.1% women, mean age 63±28 years) with ANOCA (no epicardial stenosis >50%, FFR >0.80) were enrolled between 2018 and 2023. All patients underwent wire-based assessment of coronary flow reserve (CFR) and microvascular resistance (MR) using adenosine in the left anterior descending artery. The bolus thermodilution technique was applied in 46 patients (CFR/IMR, CFRThermo) and the Doppler technique in another 116 patients (CFR/HMR, CFRDoppler). All measurements were performed according to a standardised protocol. The commonly applied cut-offs for CFR (<2.5), HMR (>2.5) and IMR (>25) were used. Results: The study population was characterized by the following risk factors: arterial hypertension (63%), hypercholesterolemia (62%), positive family history for cardiovascular disease (36%), diabetes (16%) and smoking (10%). The frequency of an abnormal CFR <2.5 was 36%. There was a significant difference between the frequency of an abnormal CFR among patients with CFRThermo (8/46, 17.4%) and patients with CFRDoppler (50/116, 43.1%, p=0.002). Moreover, the median CFR was higher in the CFRThermo group compared to the CFRDoppler group (3.5 [IQR2.8] vs. 2.6 [IQR 0.9], p<0.0005) with a much larger interquartile range in the former (Figure 1). Assessment of MR revealed an abnormal result in 20% of cases which was more often observed with the thermodilution (IMR >25 in 39.1%, median 22.5 [IQR 17.0]) compared to the Doppler technique (HMR >2.5 in 12.1%, median 1.7 [IQR 0.7], p<0.0005). Multivariable analysis revealed arterial hypertension (OR 4.04, CI 1.88 – 8.77, p<0.0005) and female sex (2.12, 1.04 - 4.34, p=0.04) as independent predictors for an abnormal CFR. Conclusion: Comparison of thermodilution and Doppler derived indexes of coronary physiology in patients with ANOCA reveals marked differences among the different measurement techniques. The results are important for the endotype classification and subsequent patient management.

Agreement of Doppler Flow Velocity Reserve With PET Flow Reserve in Patients With Angina Without Obstructive Coronary Arteries

Agreement of Doppler Flow Velocity Reserve With PET Flow Reserve in Patients With Angina Without Obstructive Coronary Arteries

Safety and feasibility of nationwide invasive coronary function testing in patients with angina and no obstructive coronary artery disease (NL-CFT)

Abstract Background and purpose Patients with angina and no obstructive coronary artery disease (ANOCA) frequently have coronary vasomotor dysfunction (CVDys) as underlying pathophysiological mechanism, comprising epicardial spasm, microvascular spasm and/or microcirculatory dysfunction. These can be diagnosed by invasive coronary function testing (CFT), which has previously shown to be safe in tertiary and expert centres. The prevalence of CVDys and safety and feasibility of CFT is reported on in this first national collaboration network on CFT’s: NL-CFT. Methods NL-CFT is a prospective, observational registry of all consecutive patients undergoing clinically indicated CFT in 15 participating hospitals throughout the Netherlands. A complete CFT consisted of acetylcholine spasm provocation testing and assessment of microcirculatory function by either bolus thermodilution or Doppler flow velocity measurements. The prevalence of six different endotypes based on CFT results and overall safety were assessed and compared between tertiary (n=2) and non-tertiary centres (n=13). Tertiary was defined as having performed over 100 CFT’s prior to the start of NL-CFT and fulfilling a referral function with specialized ANOCA outpatient clinic. Results In total 1207 predominantly female (81%) patients with a mean age of 60±10 years were included. Traditional cardiovascular risk factors were frequently present. Almost all of the included 1207 patients underwent a complete CFT (93.4%) and prevalence of CVDys was high (77%, Fig. 1). There were 11 (0.9%) serious complications reported on, of which three were definitely related to CFT as depicted in Table 1. No procedural death, myocardial infarction or stroke was observed. Lastly, no differences were found in the occurrence of complications between tertiary an non-tertiary centres. Conclusions Coronary function testing is feasible and safe to perform nationally with a high diagnostic yield.Figure 1.Endotype distribution.Table 1.Side-effects&complication rates.

Assessment of coronary endothelial dysfunction using contemporary coronary function testing

BackgroundThe established diagnosis of coronary endothelial dysfunction (CED) is through the response to low-dose acetylcholine during invasive coronary function testing (CFT). Current diagnostic criteria encompass deficient epicardial vasodilation and/or insufficient increase in coronary blood flow (CBF) calculated from additional Doppler flow velocity measurements. The aim is to evaluate the diagnostic yield of using angiographic epicardial vasomotion and CBF as single criteria for diagnosing CED during CFT. MethodsA total of 110 patients with angina and non-obstructive coronary arteries who underwent clinically indicated CFT were included. CED was defined as any reduction in epicardial diameter through quantitative coronary angiography and/or < 50 % increase in CBF compared to baseline after low-dose acetylcholine. ResultsBased on current diagnostic criteria, 78 % of patients (N = 86/110) was diagnosed with CED. When only considering epicardial diameter, 24 % CED (N = 21/86) and 50 % severe CED diagnoses (N = 19/38) were missed. When only considering CBF, 27 % CED (N = 23/86) and 18 % severe CED diagnoses (N = 7/38) were missed. A similar diagnostic yield for CED detection was found for both parameters (OR: 0.913, 95 %CI 0.481–1.726, p = 0.763). The incidence of CFT diagnoses was comparable among all groups. ConclusionsAs single parameters, both epicardial diameter and CBF were ineffective in accurately diagnosing CED compared to the current diagnostic criteria. Combining both parameters is necessary to diagnose the complete spectrum of CED, as missed diagnoses of deficient CBF responses (e.g., microvascular CED) and epicardial vasomotion (e.g., epicardial CED) might occur when relying on these parameters as single diagnostic criteria for CED.

Stroke in sickle cell patients, epidemiology, pathophysiology, systemic and surgical treatment options and prevention strategies

AbstractBackgroundA hereditary haemoglobinopathy known as sickle cell disease (SCD) affects over 100 000 people in the United States severely. Cerebrovascular disease is a prominent consequence of SCD. By the age of 30, 53% of patients have silent cerebral infarcts (SCIs) (a stroke that occurs without any obvious symptoms because it damages a small part of the brain that isn't responsible for any essential functions), and by the age of 40, 3.8% have overt strokes.Main bodyThe multidimensional burden of cerebrovascular illness in SCD is reviewed in detail in this article, which includes both clinical strokes and the frequently asymptomatic SCIs. The intricate pathophysiology of SCD and stroke is explored. With SCD, there are currently very few methods for preventing primary and secondary stroke; the most common ones are hydroxyurea and blood transfusion. Nevertheless, not enough research has been done on the possible contributions of anticoagulation and aspirin to strokes linked to SCD. Promising evidence is also highlighted in the study, suggesting that new drugs intended to treat SCD may be able to alleviate leg ulcers and renal impairment in addition to reducing unusually high transcranial Doppler flow velocity – a crucial component of cerebrovascular events. Given that these novel medications specifically target haemolysis and vaso‐occlusion, the two main causes of strokes in this population, more research is desperately needed to determine whether they are effective in avoiding strokes in people with SCD. The literature review also emphasizes how common healthcare inequities are and how they hinder advancements in SCD research and management in the United States.ConclusionTo successfully address these inequities, the evaluation recommends more funding for both SCD management and research, as well as for patient and clinician education. This multimodal viewpoint highlights the intricate terrain of cerebrovascular problems associated with SCD and the urgent need for all‐encompassing and fair strategies to improve patient outcomes and advance research.

Performance of Doppler ultrasound for fluid influx/efflux velocity estimation from borehole fractures in water-based and oil-based muds

Ultrasonic logging tools are used for several imaging applications in borehole operations. Recent studies, including from the authors of this work, have evaluated Doppler ultrasound as a potential method for obtaining greater information about influx/efflux of fluids between the borehole and formation. This work aims to further the development of Doppler ultrasound for application in borehole operations by evaluating its performance in various drilling muds. Water-based (WBM) and oil-based (OBM) drilling muds within the mud weight range of 1200 kg/m3–1800 kg/m3 are considered in this study. The study has been done experimentally using a laboratory setup pumping the drilling muds in orthogonal directions, viz. annular flow, and influx/efflux flow. Procedurally generated 3D printed fracture shapes are used for emulating the influx/efflux from borehole walls. The effect of attenuation on the signal to noise ratio (SNR) of Doppler flow images and subsequent impact on flow velocity estimates is discussed. An SNR of 1.1 dB was achieved at 45 mm depth for the heaviest OBM with a mud weight of 1640 kg/m3. Doppler flow velocity estimates could be obtained with a standard deviation of 0.528 m/s at SNR of 1.1 dB. The standard deviation reduced with increasing SNR and a minimum standard deviation of 0.209 m/s was obtained at SNR of 21.6 dB for the lightest WBM with a mud weight of 1200 kg/m3. No significant effect on the standard deviation of influx/efflux velocity estimates were observed for changes in annular flow rate.

Echocardiographic assessment of cardiovascular involvements in children with cystic fibrosis

BackgroundOver the past four decades, numerous case reports and clinical studies have highlighted the presence of heart disease in individuals with cystic fibrosis. Given the limited information in this field and the imperative to identify early changes during childhood, our study aims to explore cardiac dysfunction in patients with cystic fibrosis using echocardiography. MethodsIn this case-control study, we examined echocardiographic findings from thirty-three patients with cystic fibrosis and sixty healthy children. Demographic information for both groups was recorded, and the disease severity in patients was assessed using the Schawachman criterion. M-mode, Doppler flow velocity, and Tissue Doppler Imaging echocardiography were performed for all participants, with subsequent data analysis using SPSS 24. ResultsOur study encompassed thirty-three CF patients and sixty healthy children. The estimated pulmonary artery blood pressure (systolic and mean) in patients with cystic fibrosis was significantly higher than in the control group (P < 0.05). Additionally, the mean trans-tricuspid peak early to late diastolic flow velocity (E/A) was significantly lower in the case group than the control group (P < 0.05), along with a significantly lower mean tricuspid valve deceleration time (DT) (P < 0.05). Similarly, the mean TAPSE in the case group was notably lower than in the control group (P < 0.05). No significant difference in Mean left ventricular Ejection Fraction (EF) and Fractional Shortening (FS) existed between the two groups (P > 0.05). Furthermore, Trans-mitral peak early to late diastolic flow velocity (E/A) in the case group was significantly lower than in the control group (P < 0.05), and the mean mitral valve DT in the case group was also significantly lower (P < 0.05). ConclusionOur study findings indicate the presence of some degree of right ventricular dysfunction in children with cystic fibrosis. This finding may have implications for the development or modification of clinical guidelines for managing cystic fibrosis in children. Further investigations are recommended to elucidate the underlying mechanisms and contributing factors, providing valuable insights for clinical management.

Subclinical myocardial dysfunction among fetal growth restriction neonates: a case-control study

Objectives To evaluate cardiac structural and functional changes in neonates with fetal growth restriction (FGR) compared to appropriate-for-gestational-age (AGA) neonates using conventional echocardiography, tissue Doppler imaging (TDI), and speckle tracking echocardiography. Method This case-control study included 85 FGR neonates and 75 non-FGR, weight adequate for gestational age neonates. Among these, 37 were symmetric FGR and 48 were asymmetric FGR. All the biophysical profiles of these newborns were assessed. An echocardiographic test was performed to evaluate cardiac dimension, Left ventricular ejection fraction (LV EF), Mitral valve Doppler flow velocities, myocardial performance index, tissue annular velocities, and LV global longitudinal strain (GLS). Results Although LVEF was found to be within the normal range, mean EF was reduced among neonates with FGR than non-FGR controls (EF: 66.14 ± 3.85% vs 69.46 ± 3.58%; p < 0.001, in FGR and non-FGR, respectively). Furthermore, LV E/E’ a measure of LV diastolic function was altered among both types of FGR neonates. Similarly, LV GLS was reduced among FGR neonates (LV GLS: −20.69 ± 2.7% vs −19.06 ± 2.9%; p < 0.001 in non-FGR and FGR, respectively). Conclusion FGR neonates exhibit significant alterations in cardiac geometry compared to AGA controls. FGR neonates also demonstrated a significant reduction in LV EF, FS, and LV global longitudinal strain, depicting failure to adapt to the increased cardiac workload after birth.

Fetal Aortic and Umbilical Doppler Flow Velocity Waveforms in Pregnancy: The Concept of Aortoumbilical Column.

Low impedance within the uteroplacental circulation is crucial for fetal development. Flow velocity waveforms (FVW) have been established for the aortic and umbilical arteries in low-risk pregnancies during the second half of pregnancy, but data regarding early gestation is limited. Both vascular territories exhibit higher impedance patterns in pregnancies complicated by fetal growth restriction (FGR), hypertensive disorders, fetal anemia, and chromosomal abnormalities. Early identification of these complications is critical in obstetric practice, to reduce perinatal morbidity and mortality through prevention and close antenatal surveillance. Available data suggest that aortic and umbilical impedances follow the same variation pattern as pregnancy progresses. This observation implies that both vessels may be considered as a single artery, referred to as the "aortoumbilical column". Our hypothesis posits that changes in the hemodynamic pattern of this column could identify high-risk pregnancies, particularly those complicated by preeclampsia, FGR, intrauterine fetal demise, fetal aneuploidies, and fetal anemia. Understanding vascular embryogenesis and the FVWs of the aortic and umbilical arteries enables comprehension of impedance changes throughout normal pregnancies. The continuous variation in impedance along a single vessel supports our concept of the aortoumbilical column. Deviations from the regular pattern could assist in identifying compromised fetuses during early pregnancy. Further research on normal aortoumbilical column FVW and the development of reference charts is necessary to consider this arterial column as a screening tool in clinical practice.

Noninvasive transthoracic doppler flow velocity and invasive thermodilution to assess coronary flow reserve.

Coronary flow reserve (CFR) provides prognostication and coronary physiological information, including epicardial coronary stenosis and microvascular function. The relationship between stress transthoracic Doppler echocardiography (TDE)-derived coronary flow velocity reserve (CFRS-TDE) and thermodilution-derived coronary flow reserve (CFRthermo) before and after elective percutaneous coronary intervention (PCI) remains unclear. This single-center prospective registry study evaluated patients who underwent fractional flow reserve (FFR)-guided elective PCI for left anterior descending artery (LAD) lesions with wire-based invasive physiological measurements and pre- and post-PCI stress TDE examinations. A total of 174 LAD lesions from 174 patients were included in the final analysis. A modest correlation was detected between the pre-PCI CFRS-TDE and the pre-PCI CFRthermo (r=0.383, P<0.001). The frequently used CFRS-TDE threshold of 2.0 corresponded to a pre-PCI CFRthermo of 2.18. Pre-PCI CFRS-TDE underestimated pre-PCI CFRthermo [1.89 (1.44-2.31) vs. 2.05 (1.38-2.93), P<0.001]. Both CFRS-TDE and CFRthermo increased significantly post-PCI [pre-PCI CFRS-TDE 1.89 vs. post-PCI CFRS-TDE 2.33, P<0.001; pre-PCI CFRthermo 2.05 (1.38-2.93) vs. post-PCI CFRthermo 2.59 (1.63-3.55), P<0.001]. In contrast, there was no significant relationship between changes in CFRS-TDE and changes in CFRthermo after PCI (r=0.008, P=0.915) or between post-PCI CFRS-TDE and post-PCI CFRthermo (r=0.054, P=0.482). Pre-PCI CFRS-TDE and CFRthermo are modestly correlated, but post-PCI CFRS-TDE and CFRthermo have no correlation. CFRS-TDE and CFRthermo are not interchangeable, particularly post-PCI, suggesting that the two metrics represent different coronary physiologies after PCI.

Modeling the Relationship Between Diastolic Phenotype and Outcomes in Pediatric Hypertrophic Cardiomyopathy

Pediatric hypertrophic cardiomyopathy (HCM) is associated with adverse events. The contribution of diastolic dysfunction to adverse events is poorly understood. The aim of this study was to explore the association between diastolic phenotype and outcomes in pediatric patients with HCM. Children <18years of age with diagnosed with HCM were included. Diastolic function parameters were measured from the first echocardiogram at the time of diagnosis, including Doppler flow velocities, tissue Doppler velocities, and left atrial volume and function. Using principal-component analysis, key features in echocardiographic parameters were identified. The principal components were regressed to freedom from major adverse cardiac events (MACE), defined as implantable cardioverter-defibrillator insertion, myectomy, aborted sudden cardiac death, transplantation, need for mechanical circulatory support, and death. Variables that estimate left ventricular filling pressures were highly collinear and associated with MACE (hazard ratio, 0.86; 95% CI, 0.75-1.00), though this was no longer significant after controlling for left ventricular thickness and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with outcomes in the covariate-adjusted model (hazard ratio, 0.69; 95% CI, 0.5-0.94). The covariate-adjusted model had an Akaike information criterion of 213, an adjusted R2 value of 0.78, and a concordance index of 0.82 for association with MACE. Echocardiographic parameters of diastolic dysfunction were associated with MACE in this population study, in combination with the severity of left ventricular hypertrophy and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with adverse events. Additional study of diastolic function parameters adjusted for patient size could facilitate the prediction of adverse events in pediatric patients with HCM.

Slow verses rapid advancement of enteral feed in preterm neonates of 28-34 weeks of gestational age with abnormal antenatal umbilical artery Doppler: A randomised controlled trial

Background: Necrotising enterocolitis (NEC) is the commonest and most serious gastrointestinal neonatal emergency. In preterm infants with evidence of abnormal Doppler flow velocities in the fetal umbilical artery, suboptimal intestinal perfusion is postulated to increase the risk of feed intolerance and NEC.Objectives: To compare the effect of slow versus rapid enteral feeding in preterm neonates with abnormal antenatal umbilical artery Doppler.Method: This is a randomised controlled trial; we randomised into a slow and a fast group; we randomised separately into subcategories based on the weight. Sample size was calculated as 82. Data analysis was done using SPSS version 23. For group comparisons of categorical data, Chi-squared test was used. If expected frequency in the contingency tables was &lt;5 for more than 25% cells, Fisher’s exact test was used. For non-parametric continuous data Mann-Whitney test was applied. Statistical significance was kept at p&lt;0.05 and power at 80%.Results: In neonates with slow and rapid feeding with birth weight &lt;1250g, percentage of 2b (30% and 26.7% respectively) was more compared to other stages, whereas in group with birth weight ≥1250g rapid feeding group Ia (14.3%) was more in slow feeding group and 1a and 2a equal in rapid feeding group with no statistical significance. The mean duration of stay hospital was less in rapid feeding group in both birth strata. The sepsis percentage was more in the slow feeding group. Regarding mortality in both groups, there was no statistical difference.Conclusions: In this study the type of feeding did not affect NEC or feeding intolerance in preterm infants. Rapid feeding had a significant impact on sepsis and length of stay in preterm infants.

Transcranial Doppler Screening of Children with Sickle Cell Disease for a Large, Multinational Interventional Study: Experience from the Phase 3 HOPE-Kids 2 Trial Investigating the Effect of Voxelotor Treatment on Transcranial Doppler Flow Velocity

Introduction: Transcranial Doppler (TCD) ultrasound is an effective screening tool for identifying children with sickle cell disease (SCD) who are at high risk of stroke. Implementing TCD screening, along with appropriate therapies, for the purpose of primary stroke prevention in resource-constrained settings remains challenging. HOPE-KIDS 2 (NCT04218084) is an ongoing, phase 3, multicenter, double-blind, placebo-controlled trial of voxelotor in children with SCD and elevated arterial cerebral blood flow (measured by time-averaged maximum of the mean velocity [TAMMV]). Our aim is to describe the findings from successful implementation of a standardized TCD screening protocol that was conducted in a multinational setting. Methods: The purpose of HOPE-KIDS 2 is to evaluate the effect of voxelotor treatment on reducing the risk of stroke in participants aged 2 to &amp;lt;15 years with SCD who have conditional TAMMV (170 to &amp;lt;200 cm/s) at baseline. Children aged 2 to &amp;lt;15 years with SCD (HbSS/HbSβ 0) were screened after local sonographers were trained and certified on standardized TCD examination protocol, using the same model of Multi-Dop T digital machine (Compumedics DWL, Germany). TCD assessments were sent for central quality review and interpretation by 2 independent reviewers. STOP criteria were used to classify stroke risk: normal, &amp;lt;170 cm/s; conditional, 170 to &amp;lt;200 cm/s; or abnormal, ≥200 cm/s. Patient baseline characteristics, including clinical measurements of markers of anemia and hemolysis, were measured during study screening. The reasons for patient screen failure were summarized. Results: Between Nov 2020 and Feb 2023, 708 participants consented at 29 sites in Nigeria (n=250; 5 sites), Kenya (n=241; 4 sites), Egypt (n=145; 4 sites), Ghana (n=28; 2 sites), the US (n=17; 8 sites), Italy (n=9; 3 sites), Oman (n=9; 1 site), Saudi Arabia (n=8; 1 site), and the UK (n=1; 1 site). Of these patients, 92.1% (652/708) completed TCD screening examinations (mean [SD] age 7.6 [3.24] years; range 2.0-14.0 years; 50.8% male; 23.0% receiving hydroxyurea). Of the patients who completed TCD screening, the mean (SD) TAMMV was 163.0 (31.26) cm/s, and 47.1% (307/652) had conditional TCD at baseline (29.0% low conditional, 18.1% high conditional). The main reason for screen failure was index TAMMV outside of conditional range (abnormal, n=39 [6.0%]; normal, n=306 [46.9%]). Elevated TAMMV on screening TCD was more common in younger children (2 to ≤8 years vs &amp;gt;8 to &amp;lt;15 years); patients aged 2-8 years comprised 66.8% and 82.1% of the conditional and abnormal TCD categories, respectively. There were 39 assessments that required adjudication, but only 9 were deemed unreadable. Of all patients screened, 36.2% (236/652) fulfilled eligibility criteria for randomization; the characteristics at screening of these patients are summarized (Table). The mean (SD) Hb level and TAMMV at screening for randomly assigned patients was 7.7 (1.06) g/dL and 182.7 (7.53) cm/s, respectively. Conclusions: Clinical sites for the HOPE-KIDS 2 study successfully implemented a standardized, local TCD screening protocol supported by central quality review. For a large interventional trial aimed at reducing the risk of stroke in children with SCD, African and Middle Eastern sites presented relatively few limitations with respect to participant screening.

Sitting maneuver to uncover latent left ventricular outflow tract obstruction in patients without hypertrophic cardiomyopathy

BackgroundLeft ventricular outflow tract obstruction [LVOTO; pressure gradient (PG) ≥30 mmHg] is observed in some patients without hypertrophic cardiomyopathy (HCM), and it may develop especially in older patients without HCM (non-HCM). The aim of this study is to investigate if the Valsalva or an upright sitting maneuver can unveil latent LVOTO in patients with non-HCM. MethodsA total of 33 non-HCM patients with a late peaking or dagger-shaped pulsed Doppler waveform of the LVOT and PG <30 mmHg were included. The Doppler flow velocity of the LVOT was measured at rest, after the Valsalva and a sitting maneuver. Peak PG of ≥30 mmHg after either maneuver was defined as latent LVOTO. The angle between the left ventricular septum and the aorta in the parasternal long-axis view and the apical three-chamber view was measured. ResultsTwenty (61 %) of the 33 patients (mean age 74 ± 9 years) were diagnosed with latent LVOTO. Of these, five (25 %) patients were diagnosed after both the Valsalva and sitting maneuver, and 15 (75 %) were diagnosed only after the sitting maneuver. The latent LVOTO group had a significantly smaller angle than the no-LVOTO group between the ventricular septum and the aorta in the parasternal long axis views (107 ± 8° vs. 117 ± 8°, p < 0.01). ConclusionThe sitting maneuver is better than the Valsalva maneuver in unveiling latent LVOTO in older, non-HCM patients.

Comparative Study between Effect of Dexamethasone and Betamethasone used for Fetal Lung Maturity on Daily Fetal Movement Count and Doppler Flow Velocity Waveforms

Comparative Study between Effect of Dexamethasone and Betamethasone used for Fetal Lung Maturity on Daily Fetal Movement Count and Doppler Flow Velocity Waveforms

Associations between prenatal alcohol and tobacco exposure on Doppler flow velocity waveforms in pregnancy: a South African study

BackgroundThe negative impact of prenatal alcohol and tobacco exposure (PAE and PTE) on fetal development and birth outcomes are well described, yet pathophysiologic mechanisms are less clear. Our aim was to investigate (1) the associations between quantity, frequency and timing (QFT) of PAE and PTE with blood flow velocities in arteries of the fetal-placental-maternal circulation and (2) the extent to which combined effect of QFT of PAE and/or PTE and Doppler flow velocity waveforms (FWV) predict infant birth weight.MethodsThe Safe Passage Study is a cohort based in urban Cape Town, South Africa. Recruitment occurred between 2007 and 2015. Information on QFT of PAE and PTE was collected prospectively at up to 4 occasions during pregnancy using a modified Timeline Follow-Back approach. Ultrasound examinations consisted of Doppler flow velocity waveforms of the uterine, umbilical (UA) and fetal middle cerebral arteries for the pulsatility index (PI) at 20–24 and 34–38 weeks. Exclusion criteria included: twin pregnancies, stillbirths, participants exposed to other drugs. The sample was divided into three groups (controls, PAE and PTE) and included 1396 maternal-fetal-dyads assessed during the second trimester; 1398 assessed during the third trimester.ResultsPTE was associated with higher UA PI values in second and third trimesters (p < 0.001), compared to the PAE and control group. The total amount of cigarettes smoked during pregnancy was positively correlated with UA PI values (r = 0.087, p < 0.001). There was a positive correlation between cigarettes smoked per day in trimester one (r = 0.091, p < 0.01), and trimester two (r = 0.075, p < 0.01) and UA PI (in trimester two), as well as cigarettes smoked per day in trimester two (r = 0.058, p < 0.05) and trimester three (r = 0.069, p < 0.05) and the UA PI in trimester three. Generalized additive models indicated that PAE in trimester two, PTE in trimester one and Doppler FWV in trimester three were significant predictors of birth weight in this sample.ConclusionIn our study, PTE in trimesters two and three resulted in increased vascular resistance of the placenta. These findings highlight nuance in associations between PAE, PTE and blood flow velocities in arteries of the fetal-placental-maternal circulation and birth weight, suggesting that quantity and timing are important factors in these relationships.

Effects of Right Lateral Position on Changes of Fetal Hemodynamics in Late Pregnancy.

We aim to evaluate the effect of right lateral position on fetal hemodynamics (including umbilical artery [UA] and middle cerebral artery (MCA) blood flow-velocity waveform). In total, 150 low-risk singleton full-term pregnant women were included in the study from November 2021 to January 2022. Doppler flow velocity waveforms of the fetal UA and MCA tested by ultrasound were collected in gestation of 37-40 weeks. Computational analysis was performed using the one-way ANOVA test. Compared with the maternal left lateral position, there was a significant increase in Doppler indices of UA-RI (P = .033), UA-S/D (P = .019) and MCA-PSV (P = .021) and a significant decrease in MCA-RI (P = .030) in the supine position group. There was no statistical significance in all Doppler indices between the left and right lateral position (P > .05). Among the Doppler indices of three different maternal positions, there was no significance in both UA-PI and MCA-PI (P > .05). There were no significant differences on changes of the fetal hemodynamics between left and right lateral positions. Pregnant women could adopt to lie in the left or right lateral position alternately to relieve the discomfort in late pregnancy.

Fetal pulmonary artery Doppler blood flow velocity measures and early infant lung function. A prospective cohort study

Background Reduced lung function at birth has evident antenatal origins and is associated with an increased risk of wheezing and asthma later in life. Little is known about whether blood flow in the fetal pulmonary artery, may impact postnatal lung function. Objective Our primary aim was to investigate the potential associations between fetal Doppler blood flow velocity measures in the fetal branch pulmonary artery, and infant lung function by tidal flow-volume (TFV) loops at three months of age in a low-risk population. Our secondary aim was to explore the association between Doppler blood flow velocity measures in the umbilical and middle cerebral arteries, and the same lung function measures. Methods In 256 non-selected pregnancies from the birth cohort study Preventing Atopic Dermatitis and ALLergies in Children (PreventADALL) we performed fetal ultrasound examination with Doppler blood flow velocity measurements at 30 gestational weeks (GW). We recorded the pulsatility index, peak systolic velocity, time-averaged maximum velocity, acceleration time/ejection time ratio, and time velocity integral primarily in the proximal pulmonary artery close to the pulmonary bifurcation. The pulsatility index was measured in the umbilical and middle cerebral arteries and the peak systolic velocity in the middle cerebral artery. The cerebro-placental ratio (ratio between pulsatility index in the middle cerebral and umbilical arteries) was calculated. Infant lung function was assessed using TFV loops in awake, calmly breathing three months old infants. The outcome was the time to peak tidal expiratory flow to expiratory time ratio (t PTEF/t E), t PTEF/t E <25th percentile, and tidal volume per kg body weight (V T/kg). Potential associations between fetal Doppler blood flow velocity measures and infant lung function were assessed using linear and logistic regressions. Results The infants were born at median (min - max) 40.3 (35.6 − 42.4) GW, with a mean (SD) birth weight of 3.52 (0.46) kg, and 49.4% were females. The mean (SD) t PTEF/t E was 0.39 (0.1) and the 25th percentile was 0.33. Neither univariable nor multivariable regression models revealed any associations between fetal pulmonary blood flow velocity measures and t PTEF/t E, t PTEF/t E <25th percentile, or V T/kg at three months of age. Similarly, we did not observe associations between Doppler blood flow velocity measures in the umbilical and middle cerebral arteries and infant lung function measures. Conclusion In a cohort of 256 infants from the general population, fetal third-trimester Doppler blood flow velocity measures in the branch pulmonary, umbilical, and middle cerebral arteries were not associated with infant lung function measures at three months of age.

Sex differences in arterial stiffness and sympathetic activity in older CKD patients

Chronic kidney disease (CKD) is characterized by sympathetic nervous system overactivity that contributes to increased arterial stiffness and cardiovascular risk. While premenopausal females are relatively protected from cardiovascular disease in healthy individuals, older postmenopausal females without kidney disease have similar degrees of sympathetic overactivity, vascular stiffness and cardiovascular risk compared to older age-matched males in the general population. However, in the CKD population, cardiovascular mortality risk remains higher in older males compared to age-matched females and whether sex differences in neural and vascular function exist in older CKD patients is unknown. Therefore, we tested the hypothesis that compared to older females, older males with CKD have higher baseline sympathetic activity that is related to increased arterial stiffness. In 207 CKD patients (N=90 females, 62 ± 9 years; and N=117 males, 60 ± 9 years), we measured resting sympathetic nerve activity directed to muscle (MSNA) by microneurography at the peroneal nerve. At a separate visit, arterial stiffness was determined by carotid-to-femoral pulse wave velocity (PWV) using transcutaneous Doppler flow velocity (SphygmoCor®). Office blood pressure (BP) and 24-hour ambulatory BP monitoring (ABPM; Spacelabs) were performed using standard techniques. Resting MSNA was higher in males versus females with CKD (43 ± 10 vs 31 ± 14 bursts/min; p= 0.039). Both office and 24-hour ambulatory diastolic BP (79 ± 11 vs 67 ± 14 mmHg, p&lt;0.001) and mean arterial pressure (96 ± 10 vs 88 ± 13 mmHg, p&lt;0.001) were also higher in males versus females. PWV was not different between male and female groups (p= 0.157). There was no association between PWV and resting MSNA in males, while in females, there was an inverse relationship between PWV and MSNA burst frequency (r2=0.271; p=0.039) and burst incidence (r2=0.310; p=0.025). Older male CKD patients have higher resting MSNA, office and ambulatory BP compared to older females with CKD. In contrast, there were no differences in arterial stiffness measured as PWV between sexes. In males, increased MSNA was not associated with increased arterial stiffness, while MSNA was negatively correlated with PWV in females. Sex differences in neural and vascular function may impact cardiovascular outcomes in older patients with CKD. Supported by NIH grants R01HL135183, R33AT010457. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.