Relationship between blood flow velocity waveform and fetal behavioral states was studied in 16 normal pregnancies at 37 to 38 weeks' gestation. The peak flow velocity has demonstrated a statistically significant reduction during active sleep, as against that in quite sleep. These data reflect reduced ductal flow and suggest a redistribution in the left-ventricular and right-ventricular output in favor of the left side of the heart during active sleep. In a prospective cross-sectional study of 49 pregnancies (50 fetuses) between 25th and 38th weeks an exponential increase in breathing-related ductal blood flow velocity modulation was observed with advancing gestational age, reflecting the developing pulmonary vascular bed. Fetal ductal flow velocity waveforms were also recorded in 13 cases of prolonged severe oligohydramnios after membrane rupture before 28 weeks' gestation. Normal ductal blood flow velocity modulation values were associated with normal neonatal lung performance, whereas reduced blood flow velocity modulation values were associated with pulmonary hypoplasia. Fetal breathing-related ductal flow velocity modulation appears to be a promising predictor of neonatal lung performance.
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Ultrasound J
January 2025
Health Sciences North Research Institute, Sudbury, ON, Canada.
The duration of mechanical systole-also termed the flow time (FT) or left ventricular ejection time (LVET)-is measured by Doppler ultrasound and increasingly used as a stroke volume (SV) surrogate to guide patient care. Nevertheless, confusion exists as to the determinants of FT and a critical evaluation of this measure is needed. Using Doppler ultrasound of the left ventricular outflow tract velocity time integral (LVOT VTI) as well as strain and strain rate echocardiography as grounding principles, this brief commentary offers a model for the independent influences of FT.
View Article and Find Full Text PDFJ Gerontol A Biol Sci Med Sci
December 2024
GENUD Toledo Research Group, Faculty of Sport Sciences, University of Castilla-La Mancha, Toledo, Spain.
Mean middle cerebral artery velocity (MCAv) and the pulsatility index (PI), at rest and in response to exercise, are important markers of cerebrovascular health status in middle-aged adults, when vascular decline assumes substantial relevance. Thus, this study aimed to describe and compare the responses of MCAv and PI to incremental exercise. Two hundred and forty-eight volunteers (50-58 years, 55% women) completed a ramp test on a cycle-ergometer.
View Article and Find Full Text PDFFront Cardiovasc Med
January 2025
Pediatric Cardiology, Pediatric Heart Center, Skåne University Hospital, Lund, Sweden.
Background: Recurrent coarctation of the aorta (re-CoA) is a well-known although not fully understood complication after surgical repair, typically occurring in 10%-20% of cases within months after discharge.
Objectives: To (1) characterize geometry of the aortic arch and blood flow from pre-discharge magnetic resonance imaging (MRI) in neonates after CoA repair; and (2) compare these measures between patients that developed re-CoA within 12 months after repair and patients who did not.
Methods: Neonates needing CoA repair, without associated major congenital heart defects, were included.
Front Bioeng Biotechnol
January 2025
Department of General Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
Iliac Vein Compression Syndrome (IVCS) is a common risk factor for deep vein thrombosis in the lower extremities. The objective of this study was to investigate whether employing a porous medium model to simulate the compressed region of an iliac vein could improve the reliability and accuracy of Computational Fluid Dynamics (CFD) analysis outcomes of IVCS. Pre-operative Computed Tomography (CT) scan images of patients with IVCS were utilized to reconstruct models illustrating both the compression and collateral circulation of the iliac vein.
View Article and Find Full Text PDFFront Aging Neurosci
January 2025
Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences, Oklahoma City, OK, United States.
Introduction: Growing aging populations pose new challenges to public health as the number of people living with dementia grows in tandem. To alleviate the burden of dementia, prodromal signs of cognitive impairment must be recognized and risk factors reduced. In this context, non-invasive techniques may be used to identify early changes and monitor disease progression.
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