Doppler Flow Velocity Research Articles

Brain Magnetic Resonance Imaging and Angiography in Children with Sickle Cell Anaemia in Uganda in a Cross-Sectional Sample

Children with sickle cell anaemia (SCA) are highly susceptible to cerebrovascular injury. We performed brain magnetic resonance imaging and angiography (MRI-MRA) in Ugandan children with SCA to identify structural cerebrovascular abnormalities and examine their relationship to standardized clinical assessments. A sub-sample (n=81) was selected from a cross-sectional study of children attending SCA clinic, including 52 (64.2%) with and 29 (35.8%) without clinically detected abnormalities. Clinical evaluation included assessment for prior stroke, cognitive testing and cerebral arterial transcranial doppler (TCD) flow velocity. MRI-MRA scans were interpreted by at least two neuroradiologists. Mean age was 6.5±2.7 years, with 39 (48.1%) female. Mean haemoglobin was 7.3±0.9 g/dl. Overall, 13 (16.0%) were malnourished. Infarcts and/or stenoses were detected in 55 (67.9%) participants, with stenoses primarily in the anterior circulation. Infarcts were seen in those with normal 17/29 (58.6%) or abnormal 34/52 (65.4%) clinical testing (p=0.181). Neither abnormal MRI nor MRA was associated with age, sex, haemoglobin, or malnutrition. Abnormal MRA was highly associated with infarcts (p<0.0001). Participants with abnormal imaging had two-fold higher proportion of stroke on exam and/or impaired cognition. Stroke on exam was strongly associated with an imaging abnormality after adjusting for age, sex, malnutrition, and haemoglobin (OR 11.8, 95%CI 1.87-74.2). Over half of these SCA children had cerebrovascular infarcts and/or arterial stenoses. Cerebrovascular disease was frequently undetectable by clinical assessments. While rarely available in under-resourced settings, MRI-MRA brain imaging is an important tool for defining SCA cerebrovascular disease and for assessing impact of clinical intervention trials.

Clinical Analysis of Fetal Lung Development Index and Pregnancy Outcome in Pregnant Women with Gestational Diabetes Mellitus with Satisfactory Blood Glucose Control.

Objective To explore the regularity of fetal lung development of pregnant women with gestational diabetes mellitus (GDM) with satisfactory blood glucose control and the clinical analysis with pregnancy outcome. Methods 120 GDM pregnant women with satisfactory blood glucose control (GDM group) and 200 normal pregnant women undergoing prenatal examination (Control group) from 31 to 38 + 6 weeks of gestation were included. The two groups of pregnant women were divided into 8 time periods according to the gestational age, respectively. The parameters of Doppler flow velocity curve of fetal main pulmonary artery, diameter lines of fetal lung development, mode of delivery, neonatal weight, neonatal asphyxia, neonatal respiratory distress syndrome (NRDS), and neonatal pneumonia were, respectively, compared and analyzed between the two groups. Results Acceleration time (AT) and AT/ejection time (AT/ET) were positively correlated with gestational age, and AT/ET showed stronger correlation than AT, while no significant difference in AT and AT/ET between the two groups (P > 0.05). There was a positive correlation between the diameter of fetal lung development and gestational age, but there was no significant difference between the two groups (P > 0.05). In addition, there was no significant difference between the two groups in fetal delivery mode, neonatal weight, neonatal asphyxia, NRDS, and neonatal pneumonia (P > 0.05). Conclusion AT/ET may be a potential index to evaluate fetal lung maturity. There was no difference in fetal lung development and neonatal birth outcome between pregnant women with satisfactory GDM blood glucose control and the normal pregnant women. The pregnancy of GDM pregnant women lasts until the end of 37∼38 weeks, and the neonatal incidence rate is decreased. The key is to manipulate the blood glucose in the normal range.

Association Between Fetal Thymus Size and Intrauterine Growth Restriction

Objective: The objective of this study was to evaluate the association between reduced fetal thymus size and intrauterine growth restriction (IUGR). This study was devised to determine the association between thymus size and any abnormal Doppler indices within the fetal umbilical artery (UA), as well as the middle cerebral artery (MCA). Materials and Methods: Forty-six pregnancies between 20 and 38 weeks of gestation with IUGR and 46 normal pregnancies within similar gestational age (GA) range were included. The transverse diameter of fetal thymus was measured. In the IUGR group, the fetal umbilical artery (UA) and middle cerebral artery (MCA) Doppler flow velocities were recorded. Results: The mean GA of fetuses with IUGR (33.5 weeks) was higher than control group (30.3 weeks). To adjust for the effect of GA, analysis of covariance (ANCOVA) was performed. The adjusted mean thymus diameters were 19.02 mm in IUGR and 21.25 within the control group (mean difference = 2.23 mm; P = .02). The mean (±SD) thymus size in 16 fetuses, with abnormal Doppler findings, was significantly lower than in the group with normal Doppler findings, 17.45 (±2.50) vs 22.02 (±5.39) mm; P &lt; .001. Conclusion: IUGR may be associated with reduced fetal thymus size, especially when coupled with abnormal Doppler findings. The thymus size in a group of IUGR fetuses, with abnormal Doppler findings, was smaller than IUGR fetuses, with normal Doppler findings.

Transcranial Doppler Velocities and Angiographic Vasospasm after SAH: A Diagnostic Accuracy Study.

After aneurysmal SAH, transcranial Doppler is commonly used to monitor cerebral vasospasm. The diagnostic accuracy of transcranial Doppler flow velocity values in detecting angiographic vasospasm in patients requiring urgent endovascular intervention has not been established. We performed a retrospective analysis of a consecutive series of patients with aneurysmal SAH who underwent transcranial Doppler (index test) within 24 hours of conventional angiography (reference test). The judgment of 33%, 50%, and 66% degree of vessel narrowing on angiography was independently established by multiple neuroendovascular clinicians. Vessel-specific per-segment and per-patient transcranial Doppler velocities were studied using receiver operating characteristic curves, the Youden index, and minimal acceptable sensitivity models. Optimal mean flow-velocity thresholds were explored to calculate sensitivity and specificity using a per-patient judgment of vasospasm of at least 50% angiographic narrowing in any large arterial segment except A1. In 221 patients, vasospasm was found in 15%, 8%, and 4% of arteries when the degree of reference angiographic luminal narrowing was 33%, 50%, and 66%, respectively. Mean flow velocities were significantly higher in vasospastic segments (P = . 001), but per-segment exploratory analyses yielded unsound mean flow velocity thresholds. The Youden and minimal acceptable sensitivity models proposed mean flow velocity thresholds of approximately 160 cm/s for the anterior circulation and 80 cm/s for the posterior circulation in the per-patient diagnosis of angiographic vasospasm (≥50%), yielding a sensitivity of 80%-90% (95% CI, 0.77-0.96), but with a corresponding specificity of 50% (95% CI, 0.40-0.56). In this study, a threshold transcranial Doppler mean flow-velocity value that would accurately diagnose ≥50% angiographic vasospasm remained elusive.

A novel flow and pressure catheter for complete interventional cardiology physiology management

Abstract Ischemia with No Obstructive Coronary Artery (INOCA) in angina patients increases the risk of major cardiac events, with a 1.5x increased mortality rate. There is a link between COVID-19 infection and impairment in the myocardial micro-vasculation which may cause an increase of INOCA patients. Fractional Flow Reserve (FFR), is the standard of care in cardiology but its diagnostic function is only related to Obstructive Coronary Artery disease (or epicardial) and it is ineffective with INOCA. The lack of effective and accurate tools for timely evaluation of coronary impairments creates a clinical unmet need. The PhysioCath catheter was developed within the Eurostars project “FP-Catheter, E!113577” aims to resolve this need a provide an effective tool to interventional cardiologists. The main project outcome is a catheter prototype equipped with a blood flow velocity sensor based on a thermo-convection principle, and a fiber optic pressure sensor (based on Fabry-Perot principle). While the use of Fabry-Perot type of sensor is already standard in the industry, the use of a thermo-convection sensor represents a progress with respect the state of the art. The sensor creates an overheat of 7°C above the physiological blood's temperature (considered as being within the safety limits), and it exchanges thermal power with the blood stream. The power is then measured and converted to velocity by means of a calibration curve. The project encompassed interviews with 14 clinical experts, the summary of the interviews indicated that the preferred form of the device is an over the wire microcatheter, with rapid exchange. Within the project then, it was developed a 3Fr microcatheter, with a rapid exchange section of 24cm. Both pressure sensor and flow velocity sensor were integrated in this embodiment. Finally, the PhysioCath prototype was evaluated in a bench test study. The test setup was composed by an anatomical silicone phantom of the aortic root and the coronaries (Elastrat, Geneva, Switzerland), perfused with a peristaltic pump (Harvard Apparatus, Holliston MA, US). The measurements performed by the flow velocity sensor were compared against and external doppler flow velocity sensor. While the pressure measurement was assessed for stability and presence of drift. The data processing revealed and extreme accuracy in the measurement of flow based indexes like CFR (±6% variability), accuracy of the blood flow velocity measurement (±10%), and extreme stability in the measurement of both pressure and flow velocity. In the second part of the project (that is currently ongoing), it will be studied the performance of the device within an animal setting. In conclusion, the PhysioCath device is a microcatheter integrating bot pressure measurement and blood flow velocity measurement. Its performance is of very high accuracy and stability, that represent a main step ahead with respect the current state of the art, based mainly on thermodilution. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Eureka-Eurostars Test benchMicrocatheter prototype

Effect of the loading dose of magnesium sulfate on the Doppler velocimetry parameters in the uterine, umbilical and fetal middle cerebral arteries in severe preeclampsia

Abstract Background Preeclampsia is pregnancy-specific syndrome of reduced organ perfusion secondary to vasospasm and endothelial activation. Aim of the Work to assess the effect of injecting magnesium sulfate on Doppler parameters of uterine artery, umbilical and fetal middle cerebral arteries (MCA) in women with severe preeclampsia. Patients and Methods This study included eighty pregnant with severe preeclampsia or eclampsia who were given magnesium sulphate therapy in Ain Shams University Maternity hospital. The Study group included 80 pregnant patients Doppler flow velocity parameters (resistance index [RI], pulsatility index [PI] and systolic/diastolic [S/D] ratio) were evaluated in the uterine, fetal umbilical and middle cerebral arteries before and 20 minutes after intravenous administration of 6 grams of magnesium sulfate (Loading dose). Results Magnesium sulfate had significant hemodynamic effects with significant reduction of systolic and diastolic blood pressure. Regarding the Doppler studies, it was found that after administration of magnesium sulfate there was significant reduction in the Doppler velocimetry parameters (Resistance index[RI], Pulsatility index[PI] and systolic/diastolic[S/D] ratio) in the uterine, umbilical and fetal middle cerebral arteries denoting decreased vascular resistance with increased blood flow in these vessels. Conclusion Intravenous administration of magnesium sulfate in pregnant women with severe preeclampsia and eclampsia resulted in a decrease in uterine artery, fetal umbilical and middle cerebral arteries Doppler indices with reduced resistance to blood flow in these vessels.

Wall shear stress mapping for human femoral artery based on ultrafast ultrasound vector Doppler estimations.

Wall shear stress (WSS), a type of friction exerted on the artery wall by flowing blood, is considered a crucial factor in atherosclerotic plaque development. Currently, achieving a reliable WSS mapping of an artery noninvasively by using existing imaging modalities is still challenging. In this study, a WSS mapping based on vector Doppler flow velocity estimation was proposed to measure the dynamic WSS on the human femoral artery. Because ultrafast ultrasound imaging was used here, flow-enhanced imaging was also performed to observe the moving blood flow condition. The performance of WSS mapping was verified using both straight (8mm in diameter) and stenosis (70% of stenosis) phantoms under a pulsatile flow condition. A human study was conducted from five healthy volunteers. Experimental results demonstrated that the WSS estimation was close to the standard value that was obtained from maximum velocity estimation in straight phantom experiments. In a stenosis phantom experiment, a low WSS region was observed at a site downstream of an obstruction, which is a high-risk area for plaque formation. Dynamic WSS mapping was accomplished in measurement in the femoral artery bifurcation. In measurements, the time-averaged WSS of the common femoral artery, superficial femoral artery, and deep femoral artery was 0.52± 0.19, 0.44 ± 0.21, and 0.29 ± 0.16Pa, respectively, for the anterior wall and 0.29 ± 0.11, 0.54 ± 0.24, and 0.23 ± 0.10Pa, respectively, for the posterior wall. All results indicated that WSS mapping has the potential to be a useful tool for vessel duplex scanning in the future.

Associations Between Transcranial Doppler Flow Velocities, Laboratory Parameters, and Clinical Features in Turkish Children With Sickle Cell Disease.

Stroke is one of the major complications of sickle cell disease (SCD). Stroke features either occlusion of, or stenosis at, the origin of one of the large intracerebral arteries, the internal carotid artery (ICA), and/or the middle cerebral artery (MCA). We sought correlations between cerebral blood flow velocities and the laboratory and clinical findings of patients with SCD. Fifty-three pediatric SCD patients (39 with HbSS, 14 with HbSβ0) were analyzed. The mean patient age was 12.9±3.9 years. The control group contained 24 healthy individuals. The time-averaged maximum mean velocity (TAMMV) and resistive index (RI) of the MCA, the TAMMVs of the ICA and vertebral artery (VA), and the diameter of the VA were estimated through transcranial Doppler ultrasonography using a 2.5 MHz transducer, in accordance with the Stroke Prevention Trial in Sickle Cell Anemia (STOP) protocol. We evaluated the relationships between the TAMMVs, laboratory parameters, and clinical findings. The mean±SD MCA TAMMV was 161.2±35.4 cm/s in patients with HbSS and 185.8±62.9 cm/s in patients with HbSβ0. The mean MCA TAMMV, RI, ICA TAMMV, VA TAMMV, and VA diameter were 168.5±43.9 cm/s, 0.63±0.06, 116.8±25.5 cm/s, 69.2±18.5 cm/s, and 3.5±0.61 mm for all SCD patients, respectively. In the control group, the mean MCA TAMMV, RI, ICA TAMMV, VA TAMMV, and VA diameter were 103.8±28.8 cm/s, 0.53±0.04, 96.4±27.8 cm/s, 40.3±12.1 cm/s, and 3.4±0.6 mm, respectively. Although the differences were not significant, TAMMVs were higher in HbSβ0 patients taking hydroxyurea; those with hemoglobin levels <8 g/dL, ferritin levels >1000 ng/dL, mean platelet volume >12 fL, or red cell distribution width >18%; or required chelation, or were below the third percentiles of weight and height. The TAMMV was significantly higher only in SCD patients who complained of headache. High ferritin and low hemoglobin levels, a high mean platelet volume, a high red cell distribution width, low weight (below the third percentile), and a short height (below the third percentile) may be associated with elevated cerebral blood flow velocities and an increased stroke risk in children with SCD. Children with such features should be closely followed-up through transcranial Doppler ultrasonography examination.

Prognostic implications of pulmonary wave reflection and reservoir pressure in patients with pulmonary hypertension

BackgroundRight ventricular (RV) coupling to the pulmonary circulation influences the response of the RV to the increased afterload caused by pulmonary hypertension (PH), which ultimately determines prognosis. A methodology that accounts for pulsatile flow is required when assessing ventriculo-arterial coupling. We applied wave intensity analysis (WIA) methods to assess the compliance of the main pulmonary artery (PA) in patients with or without PH and compared this to PA distensibility, RV function and clinical outcomes. MethodsHigh-fidelity blood pressure and Doppler flow velocity tracings were obtained simultaneously during cardiac catheterisation for suspected PH. RV volumes, main PA distensibility and ventriculo-arterial coupling (Emax/Ea) were analysed using cardiovascular magnetic resonance. ResultsThe study included 17 ​PH patients and 6 controls. Wave speed, reservoir and excess pressure were higher in PH patients compared to controls (p ​< ​0.01 for all). Waveforms relating to RV ejection, microvascular wave reflection and late systolic proximal deceleration were higher in PH patients compared to controls (p ​< ​0.01 for all) and related to echocardiographic findings, including PA Doppler notching and shortened acceleration time. Wave speed, reservoir pressure and excess pressure were strongly correlated to main PA distensibility, RV function and Emax/Ea. A higher total pressure integral was associated with an increased risk of death (all-cause mortality). ConclusionThe reservoir-excess pressure model, in combination with conventional clinical imaging, provides valuable information on the pathophysiology of PH that standard haemodynamic parameters do not. Future studies should further investigate the prognostic implications of WIA in PH, and its potential role in clinical practice.

Fetal Thoracic Circumference and Lung Volume and Their Relation to Fetal Size and Pulmonary Artery Blood Flow.

Research on early origins of lung disease suggests the need for studying the relationships of thoracic and lung size with fetal size and pulmonary circulation. The primary aim of this study is therefore to explore the associations between fetal thoracic circumference, lung volume, and fetal size. We also aim to assess if lung volume and thoracic circumference are associated with fetal pulmonary artery blood flow velocity measures. Cross-sectional assessment of singleton pregnancies from the general population (n=447) at 30 gestational weeks (GW) was performed using ultrasound measurement of fetal thoracic circumference, lung volume, head and abdominal circumference, and femur length. We obtained Doppler blood flow velocity measures from the proximal branches of the fetal pulmonary artery. Associations between variables were studied using Pearson's correlation and multiple linear regression analyses. Both thoracic circumference and lung volume correlated with fetal size measures, ranging from r=0.64 between thoracic circumference and abdominal circumference, to r=0.28 between lung volume and femur length. Adjustment for gestational age, maternal nicotine use, pre-pregnancy body mass index, and fetal sex marginally influenced the associations with abdominal circumference. The correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures were weak (r ≤ 0.17). We found moderate to low correlation between thoracic circumference, lung volume, and fetal size at 30 GW. The closest relationship was with the abdominal circumference. We found low correlations of thoracic circumference and lung volume with pulmonary artery blood flow velocity measures.

Assessment of right ventricular function after successful percutaneous coronary intervention to chronic total occlusion using different echo-Doppler modalities

Background and aim Chronic total occlusion is a common condition in patients with coronary artery disease and represents one of the most challenging targets of lesion recanalization with successful percutaneous coronary intervention (PCI). Different echo-Doppler modalities can be used for the assessment of right ventricular (RV) performance in patients undergoing PCI with reported superiority of the newer modalities. The aim was to assess the effect of successful PCI for chronic totally occluded vessel on the RV performance by different echo-Doppler modalities. Patients and methods The present study enrolled 25 patients with chronic total occlusion for whom PCI was performed. Patients were subjected to history taking, clinical assessment, 12-lead surface ECG, and evaluation of RV functions before, within 48 h after successful PCI, and 1 month later, using conventional and new echo-Doppler modalities. Echo-Doppler parameters included RV dimensions, Doppler flow velocities (E, A, and E/A) across tricuspid valves, RV fractional area change (RV-FAC), tricuspid annular plane systolic excursion, tissue Doppler systolic, and diastolic velocities (Sa, Ea, and Aa) at the lateral tricuspid annulus, in addition to evaluation of RV global longitudinal strain (RV-GLS). Results There was no significant improvement of parameters reflecting RV function comparing the pre-PCI and 48-h post-PCI values. On the contrary, significant improvement was detected comparing the echo-Doppler measures of either the pre- or 48-h PCI value with those of 1 month later. There was a significant increase of RV-FAC, tricuspid Sa and Ea, and RV-GLS (P&lt;0.05). The E/A ratio of tricuspid flow and tricuspid annular plane systolic excursion showed no significant difference from pre- to 48 hr or 1-month PCI value. Conclusion RV performance improves after successful PCI of chronic totally occluded vessels. Newer echo-Doppler modalities appear to be better tools for assessment of RV performance.

Variability of echocardiographic measures of left ventricular diastolic function. The HUNT study.

Investigate variability related to image acquisition and reading process for echocardiographic measures of left ventricular (LV) diastolic function, and its influence on classification of LV diastolic dysfunction (LVDD). Forty participants (19 women) mean age 62 (28-88) years underwent echocardiographic examinations twice by different echocardiographers and blinded analyses by four readers in a cross-sectional design. Measurements included quantification of two- (2D) and three-dimensional (3D) recordings of the left atrium (LA) (maximal) volume (LAVmax ) and spectral Doppler blood flow and tissue velocities for assessment of LV diastolic function. Variability and reproducibility measures were calculated using variance component analyses and Kappa statistics. Image acquisition influenced variability more than image reading (mean 24% and 4% of variance, respectively), but variability from image reading was especially important for 2D LAVmax (16% of variance) compared to 4% for 3D LAVmax , which was reflected in better agreement for 3D measures. The variability of measures used in classification of LVDD had clinical significance, and agreement across the four raters in classification using current recommendations was only fair (Kappa 0.42), but the agreement improved when using 3D LAVmax (Kappa 0.58). Agreement and reliability measures were reported for all measures. Performing a new image acquisition influenced variability more than a introducing a new image reader, but there were differences across the different measures. LAVmax by 3D is superior to 2D with respect to lower variability. The variability of diastolic measures influences the reliability of LVDD classification, and this should be taken into account in the everyday clinic.

Concentrations of estradiol, progesterone and testosterone in serum and cerebrospinal fluid of patients with aneurysmal subarachnoid hemorrhage correlate weakly with transcranial Doppler flow velocities

BackgroundThe implication of the steroids estradiol, progesterone and testosterone in cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH) has not been comprehensively assessed. In rodents, studies suggested beneficial effects of steroids on cerebral vasospasm after experimental SAH. Studies in humans are warranted, however, a general dilemma of human studies on neuroactive substances is that the brain is not directly accessible and that concentrations in the periphery may not adequately parallel concentrations in the central compartments. In the present study, concentrations of estradiol, progesterone and testosterone in serum and cerebrospinal fluid (CSF) of patients with aSAH were determined. Blood flow velocities in cerebral arteries were measured by transcranial Doppler sonography (TCD). The aim of this study was to evaluate the correlations between the cerebral blood flow velocities and levels of estradiol, progesterone and testosterone in CSF and serum.ResultsSamples of serum and CSF of 42 patients with aSAH were collected concomitantly daily or every other day via the arterial line and the external ventricular drainage for two weeks after the hemorrhage. Blood flow velocities in the cerebral arteries were determined by TCD. Total estradiol, progesterone and testosterone concentrations were measured by electro-chemiluminescence immunoassay. The strength of correlation was assessed by Spearman’s rank correlation coefficient. The correlation analysis revealed very weak correlations between cerebral blood flow velocities and concentrations of estradiol, progesterone and testosterone levels in both compartments with correlation coefficients below 0.2.ConclusionsIn humans with aSAH, merely very weak correlations between flow velocities in cerebral arteries and concentrations of estradiol, progesterone and testosterone in serum and CSF were demonstrated. These results suggest a limited influence of the respective steroids on cerebral vascular tone although vasodilatory effects were described in rodent studies. Thus, the implication of steroids in processes of neurological deterioration warrants further clarification.

Impact of clinical and haemodynamic factors on coronary flow reserve and invasive coronary flow capacity in non-obstructed coronary arteries: a patient-level pooled analysis of the DEBATE and ILIAS studies.

Coronary flow reserve (CFR) is a physiological index for the assessment of myocardial flow impairment due to focal or microcirculatory coronary artery disease (CAD). Coronary flow capacity (CFC) is another flow-based concept in diagnosing ischaemic heart disease, based on hyperaemic average peak velocity (hAPV) and CFR. We evaluated clinical and haemodynamic factors which potentially influence CFR and CFC in non-obstructed coronary arteries. Intracoronary Doppler flow velocity measurements to obtain CFR and CFC were performed after inducing hyperaemia in 390 non-obstructed vessels of patients who were scheduled for elective percutaneous coronary intervention (PCI) of another vessel. Akaike's information criterion (AIC) revealed age, female gender, history of myocardial infarction, hypercholesterolaemia, diastolic blood pressure, oral nitrates and rate pressure product as independent predictors of CFR and CFC. After regression analysis, age and female gender were associated with lower CFR and age was associated with worse CFC in angiographically non-obstructed vessels. Age and female gender are associated with lower CFR, and age with worse CFC in an angiographically non-obstructed coronary artery. CFC seems to be less sensitive to variations in clinical and haemodynamic parameters than CFR and is therefore a promising tool in contemporary clinical decision making in the cardiac catheterisation laboratory.

The Association Between Notching of the Right Ventricular Outflow Tract Flow Velocity Doppler Envelope and Impaired Right Ventricular Function After Acute High-Altitude Exposure.

IntroductionPulmonary artery pressure (PAP) is increased and right ventricular (RV) function is well preserved in healthy subjects upon exposure to high altitude (HA). An increase in PAP may trigger notching of the right ventricular outflow tract Doppler flow velocity envelope (RVOT notch), which is associated with impaired RV function in patients with pulmonary hypertension. However, whether HA exposure can induce RVOT notch formation and the subsequent impact on cardiac function in healthy subjects remains unclear.MethodsA total of 99 subjects (69 males and 30 females) with a median age of 25 years were enrolled in this study; they traveled from 500 to 4100 m by bus over a 2-day period. All subjects underwent a comprehensive physiological and echocardiographic examination 1 day before ascension at low altitude and 15 ± 3 h after arrival at HA. The RVOT notch was determined by the presence of a notched shape in the RVOT Doppler flow velocity envelope. The systolic PAP (SPAP) was calculated as Bernoulli equation SPAP = 4 × (maximum tricuspid regurgitation velocity)2+5 and mean PAP (mPAP) = 0.61 × SPAP+2. Cardiac output was calculated as stroke volume × heart rate. Pulmonary capillary wedge pressure (PCWP) was calculated as 1.9+1.24 × mitral E/e’. Pulmonary vascular resistance (PVR) was calculated as (mPAP-PCWP)/CO.ResultsAfter HA exposure, 20 (20.2%) subjects had an RVOT notch [notch (+)], and 79 (79.8%) subjects did not have an RVOT notch [notch (−)]. In the multivariate logistic regression analysis, the SPAP, right ventricular global longitude strain (RV GLS), and tricuspid E/A were independently associated with the RVOT notch. The SPAP, mPAP, PVR, standard deviations of the times to peak systolic strain in the four mid-basal RV segments (RVSD4), peak velocity of the isovolumic contraction period (ICV), and the peak systolic velocity (s’) at the mitral/tricuspid annulus were increased in all subjects. Conversely, the pulse oxygen saturation (SpO2), RV GLS, and tricuspid annulus plane systolic excursion (TAPSE)/SPAP were decreased. However, the increases of SPAP, mPAP, PVR, and RVSD4 and the decreases of SpO2, RV GLS, and TAPSE/SPAP were more pronounced in the notch (+) group than in the notch (−) group. Additionally, increased tricuspid ICV and mitral/tricuspid s’ were found only in the notch (−) group.ConclusionHA exposure-induced RVOT notch formation is associated with impaired RV function, including no increase in the tricuspid ICV or s’, reduction of RV deformation, deterioration in RV-pulmonary artery coupling, and RV intraventricular synchrony.

Increased Ipsilateral Posterior Cerebral Artery P2-Segment Flow Velocity Predicts Hemodynamic Impairment.

Increased Transcranial Doppler flow velocity in the ipsilateral P2-segment of the posterior cerebral artery (PCA-P2: cm/second) is associated with recurrent cerebrovascular events in patients with unilateral internal carotid artery occlusion. However, its predictive value and correlation with hemodynamic impairment in an overall stroke patient cohort remains to be determined. Transcranial doppler PCA-P2 flow velocity was measured in 88 patients with symptomatic unilateral steno-occlusive disease who also underwent blood oxygenation-level dependent cerebrovascular reactivity imaging (blood oxygenation-level dependent [BOLD]-cerebrovascular reactivity [CVR]). A multivariate linear regression was used to evaluate the independent correlation between the ipsilateral PCA-P2 flow velocity measurements and hemispheric BOLD-CVR. Follow-up BOLD-CVR imaging data, available in 25 patients, were used to evaluate the temporal evolution of the BOLD-CVR and PCA-P2 flow velocity association using a mixed-effect model. Furthermore, a transcranial doppler cutoff for hemodynamic failure stage 2 was determined. The ipsilateral systolic PCA-P2 flow velocity strongly correlated with hemispheric BOLD-CVR (R=0.79; R2=0.61), which remained unchanged when evaluating the follow-up data. Using a PCA-P2 systolic flow velocity cutoff value of 85 cm/second, patients with BOLD-CVR based hemodynamic failure stage 2 were diagnosed with an area under the curve of 95. In patients with symptomatic unilateral steno-occlusive disease, increased ipsilateral transcranial doppler PCA-P2 systolic flow velocity independently correlates with BOLD-CVR based hemodynamic failure. A cutoff value of 85 cm/second appears to indicate hemodynamic failure stage 2, but this finding needs to be validated in an independent patient cohort.

Assessment of Myocardial Mechanics in Patients Undergoing Pericardiectomy for Chronic Constrictive Pericarditis by Tissue Doppler Imaging and 2D Speckled Tracking Echocardiography: A Prospective Obser

Background: This study was designed to prospectively evaluate the changes in tissue Doppler imaging (TDI) at mitral and tricuspid annuli and two dimensional speckle tracking echocardiography in patients undergoing pericardiectomy for chronic constrictive pericarditis and identify the relationship if any of the tissue Doppler imaging and speckle echocardiographic derived variables with patient’s symptomatic status following surgery. Patients and Methods: Twelve patients undergoing pericardiectomy for constrictive pericarditis aged 7 years to 70 years (median 21; IQR: 19.75-26.5 years) were studied for 2-36 months (median 19 months). They underwent Doppler flow velocity, TDI, and 2D-speckle echocardiographic studies. Friedman’ test was used to test the changes in TDI-derived mitral and tricuspid annular velocities and speckle derived parameters in postoperative period from baseline. Results: Despite congestive heart failure, all patients had normal left ventricular ejection fraction and increased medial mitral and tricuspid early diastolic septal velocity (e¢) with “annulus reversus”. This pattern of annular velocity improved maximally in the immediate postoperative period. At closing interval, 2 (16.7%) patients continued to be in New York Heart Association class II and both of them continued to remain in atrial fibrillation. There was statistical significant improvement in the Global cirumferential strain than in global longitudinal and global radial strain after pericardiectomy. Conclusions: We conclude that tissue Doppler imaging and speckle tracking echocardiography are useful investigative modalities for serial evaluation of patients undergoing pericardiectomy. It can be performed serially with a high degree of reproducibility.

Classification of intrauterine growth restriction at 34-38 weeks gestation with machine learning models.

Objective:Intrauterine growth restriction (IUGR) is one of the most common causes of stillbirths. The objective of this study is to develop a machine learning model that will be able to accurately and consistently predict whether the estimated fetal weight (EFW) will be below the 10th percentile at 34+0–37 + 6 week’s gestation stage, by using data collected at 20 + 0 to 23 + 6 weeks gestation.Methods:Recruitment for the prospective Safe Passage Study (SPS) was done over 7.5 years (2007–2015). An essential part of the fetal assessment was the non-invasive transabdominal recording of the maternal and fetal electrocardiograms as well as the performance of an ultrasound examination for Doppler flow velocity waveforms and fetal biometry at 20 + 0 to 23 + 6 and 34 + 0 to 37 + 6 week’s gestation. Several predictive models were constructed, using supervised learning techniques, and evaluated using the Stochastic Gradient Descent, k-Nearest Neighbours, Logistic Regression and Random Forest methods.Results:The final model performed exceptionally well across all evaluation metrics, particularly so for the Stochastic Gradient Descent method: achieving a 93% average for Classification Accuracy, Recall, Precision and F1-Score when random sampling is used and 91% for cross-validation (both methods using a 95% confidence interval). Furthermore, the model identifies the Umbilical Artery Pulsality Index to be the strongest identifier for the prediction of IUGR – matching the literature. Three of the four evaluation methods used achieved above 90% for both True Negative and True Positive results. The ROC Analysis showed a very strong True Positive rate (y-axis) for both target attribute outcomes – AUC value of 0.771.Conclusions:The model performs exceptionally well in all evaluation metrics, showing robustness and flexibility as a predictive model for the binary target attribute of IUGR. This accuracy is likely due to the value added by the pre-processed features regarding the fetal gained beats and accelerations, something otherwise absent from previous multi-disciplinary studies. The success of the proposed predictive model allows the pursuit of further birth-related anomalies, providing a foundation for more complex models and lesser-researched subject matter. The data available for this model was a vital part of its success but might also become a limiting factor for further analyses. Further development of similar models could result in better classification performance even with little data available.

Assessment of the Impact of Percutaneous Coronary Intervention to Chronic Total Occlusion on the Ventricular Performance Using Different Echo-Doppler Modalities

Background: Chronic total occlusion (CTO) of coronary arteries represents one of the most challenging targets of lesion recanalization with percutaneous coronary intervention (PCI). The rationale for recanalization of CTO is the possible improvement of ventricular function. Different echo-Doppler modalities can be used for the assessment of ventricular performance with reported superiority of the newer modalities. Aim: To assess the impact of successful percutaneous coronary intervention for chronic totally occluded vessel on the ventricular performance using different echo-Doppler modalities. Methods: This study enrolled 30 patients with CTO for whom PCI was performed. Patients were subjected to thorough clinical assessment, Echo-Doppler evaluation of LV and RV functions before, within 48-hrs after successful PCI and one-month later, Echo-Doppler parameters included LV dimension, LV volumes, biplane and 3D-LV ejection fraction (LVEF), mitral Doppler-flow velocities (E, A & E/A), mitral valve early deceleration time (MV-EDT), mitral tissue Doppler systolic & diastolic annular velocities (Sa, Ea and Aa), LV global longitudinal strain (GLS). Results: There was no significant improvement of parameters reflecting LV function comparing the pre and 48-hrs post PCI. On the other hand, significant improvement was detected comparing the echo-Doppler measures of either the pre or 48-hours after PCI with those of one-month later. There was significant increase of biplane-LVEF (p

Predictive value of the transcranial Doppler and mean arterial flow velocity for early detection of cerebral vasospasm in aneurysmal subarachnoid hemorrhage

We aimed to predict cerebral vasospasm in acute aneurysmal subarachnoid hemorrhage and to determine the cut-off values of the mean flow velocity by the use of transcranial Doppler. A total of 40 patients with acute aneurysmal subarachnoid hemorrhage were included in this study and classified into two groups. The first group was 26 patients (65%) with cerebral vasospasm and the second group was 14 patients (35%) without vasospasm. Initial evaluation using the Glasgow Coma Scale and the severity of aneurysmal subarachnoid hemorrhage was detected by using both the clinical Hunt and Hess and radiological Fisher grading scales. All patients underwent transcranial Doppler evaluations five times in 10 days measuring the mean flow velocities (MFV) of cerebral arteries. Patients with cerebral vasospasm were associated with significantly higher mean Glasgow Coma Scale score (p = 0.03), significantly higher mean Hunt and Hess scale grades (p = 0.04), with significantly higher mean diabetes mellitus (p = 0.03), significantly higher mean systolic blood pressure and diastolic blood pressure (p = 0.02 and p = 0.005 respectively) and significantly higher MFVs measured within the first 10 days. Logistic regression analysis demonstrated that MFV ≥81 cm/s in the middle cerebral artery is accompanied by an almost five-fold increased risk of vasospasm (OR 4.92, p < 0.01), while MFV ≥63 cm/s in the anterior cerebral artery is accompanied by a three-fold increased risk of vasospasm (OR 3.12, p < 0.01), and MFV ≥42 cm/s in the posterior cerebral artery is accompanied by a two-fold increased risk of vasospasm (OR 2.11, p < 0.05). Transcranial Doppler is a useful tool for early detection, monitoring, and prediction of post subarachnoid vasospasm and valuable for early therapeutic intervention before irreversible ischemic neurological deficits take place.