Theoretical models of retinal hemodynamics showed the modulation of retinal pulsatile patterns (RPPs) by heart rate (HR), yet in-vivo validation and scientific merit of this biological process is lacking. Such evidence is critical for result interpretation, study design, and (patho-)physiological modeling of human biology spanning applications in various medical specialties. In retinal hemodynamic video-recordings, we characterize the morphology of RPPs and assess the impact of modulation by HR or other variables. Principal component analysis isolated two RPPs, i.e., spontaneous venous pulsation (SVP) and optic cup pulsation (OCP). Heart rate modulated SVP and OCP morphology (pFDR < 0.05); age modulated SVP morphology (pFDR < 0.05). In addition, age and HR demonstrated the effect on between-group differences. This knowledge greatly affects future study designs, analyses of between-group differences in RPPs, and biophysical models investigating relationships between RPPs, intracranial, intraocular pressures, and cardiovascular physiology.
- MeSH
- discus nervi optici * MeSH
- lidé MeSH
- nitrooční tlak MeSH
- pulzatilní průtok fyziologie MeSH
- srdeční frekvence MeSH
- vena centralis retinae * fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
INTRODUCTION: This study aimed to determine the effect and clinical impact of physiological characteristics on the 95th/5th centile of the umbilical artery (UA) Doppler and the cerebroplacental ratio (CPR), at 36+ weeks. METHODS: From the multicenter randomized trial "Ratio37," we selected 4,505 low-risk pregnant women between June 2016 and January 2020. We registered physiological characteristics and the pulsatility indexes (PI) of the UA and middle cerebral artery (36-39 weeks). The 95th/5th centile of the UA PI and CPR was modeled by quantile regression. To evaluate the clinical impact of adjusting Doppler, we retrospectively applied gestational age (GA) and fully adjusted standards to 682 small for gestational age (SGA)-suspected fetuses (37 weeks) from a cohort of consecutive patients obtained between January 2010 and January 2020. RESULTS: Several physiological characteristics significantly influenced the 95th/5th centile of the UA and CPR PI. The fully adjusted 95th centile of the UA was higher, and the 5th centile of the CPR was lower than GA-only-adjusted standards. Of the 682 SGA fetuses, 150 (22%) were classified as late fetal growth restricted only by GA and 112 (16.4%) when we adjusted Doppler. These 38 fetuses had similar perinatal outcome than the SGA group. DISCUSSION: The 95th/5th centile of the UA and CPR PI is significantly influenced by physiological characteristics. Adjusting Doppler standards could differentiate better between FGR and SGA.
- MeSH
- arteria cerebri media diagnostické zobrazování MeSH
- arteriae umbilicales diagnostické zobrazování MeSH
- gestační stáří MeSH
- hypotrofický novorozenec MeSH
- lidé MeSH
- novorozenec MeSH
- placenta * diagnostické zobrazování MeSH
- plod MeSH
- pulzatilní průtok MeSH
- retrospektivní studie MeSH
- růstová retardace plodu * diagnostické zobrazování MeSH
- těhotenství MeSH
- ultrasonografie dopplerovská MeSH
- ultrasonografie prenatální MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- randomizované kontrolované studie MeSH
BACKGROUND: Implantation of current generation left ventricular assist devices (LVADs) in the treatment of end-stage heart failure (HF), not only improves HF symptoms and end-organ perfusion, but also leads to cellular and molecular responses, presumably in response to the continuous flow generated by these devices. MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression in multiple biological processes, including the pathogenesis of HF. In our study, we examined the influence of long-term LVAD support on changes in flow-sensitive miRNAs in plasma. MATERIALS AND METHODS: Blood samples from patients with end-stage heart failure (N = 33; age = 55.7 ± 11.6 years) were collected before LVAD implantation and 3, 6, 9, and 12 months after implantation. Plasma levels of the flow-sensitive miRNAs; miR-10a, miR-10b, miR-146a, miR-146b, miR-663a, miR-663b, miR-21, miR-155, and miR-126 were measured using quantitative PCR. RESULTS: Increasing quantities of miR-126 (P < 0.03) and miR-146a (P < 0.02) was observed at each follow-up visit after LVAD implantation. A positive association between miR-155 and Belcaro score (P < 0.04) and an inverse correlation between miR-126 and endothelial function, measured as the reactive hyperemia index (P < 0.05), was observed. CONCLUSIONS: Our observations suggest that after LVAD implantation, low pulsatile flow up-regulates plasma levels of circulating flow-sensitive miRNAs, contributing to endothelial dysfunction and vascular remodeling.
- MeSH
- dospělí MeSH
- kvantitativní polymerázová řetězová reakce MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikro RNA * genetika MeSH
- podpůrné srdeční systémy * MeSH
- pulzatilní průtok MeSH
- senioři MeSH
- srdeční selhání * diagnóza genetika terapie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Noninvasive diagnostic methods utilizing pulse wave measurements on the surface of the head are an important tool in diagnosing various types of cerebrovascular disease. The measurement of extraorbital pressure fluctuations reflects intraocular and intracranial pressure changes and can be used to estimate pressure changes in intracranial arteries and the collateral circulation. NEW METHOD: In this paper, we describe our patented (CZ 305757) digital device for noninvasive measuring and monitoring of orbital movements using pressure detection. We conducted preclinical tests (126 measurements on 42 volunteers) to evaluate the practical capabilities of our device. Two human experts visually assessed the quality of the pressure pulsation and discriminability among various test conditions (specifically, subject lying, sitting, and the Matas carotid occlusion test). RESULTS: The results showed that our device provided clinically relevant outcomes with a sufficient level of detail of the pulse wave and a high reliability (not less than 85%) in all clinically relevant situations. It was possible to record the effect of the Matas carotid occlusion test. COMPARISON WITH EXISTING METHOD(S): Our fully noninvasive, lightweight (185 g), portable, and wireless device provides a considerably cheaper alternative to the current diagnostic methods (e.g., transcranial ultrasound, X-ray, or MRI angiography) for specific assessment of cerebral circulation. Within a minute, it can detect the Willis circle integrity and thus eliminate the potential risks associated with the Matas test using standard EEG. CONCLUSIONS: Our device represents an improvement and a valid alternative to the current methods diagnosing regional cerebral circulation.
- MeSH
- circulus arteriosus Willisi fyziologie MeSH
- design vybavení * MeSH
- lidé MeSH
- mozkový krevní oběh fyziologie MeSH
- orbita * krevní zásobení MeSH
- pletysmografie přístrojové vybavení normy MeSH
- pulzatilní průtok fyziologie MeSH
- regionální krevní průtok fyziologie MeSH
- reprodukovatelnost výsledků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
INTRODUCTION: Long-term use of continuous-flow left ventricular assist devices may have negative consequences for autonomic, cardiovascular and gastrointestinal function. It has thus been suggested that non-invasive monitoring of arterial pulsatility in patients with a left ventricular assist device is highly important for ensuring patient safety and longevity. We have developed a novel, semi-automated frequency-domain-based index of arterial pulsatility that is obtained during suprasystolic occlusions of the upper arm: the 'cuff pulsatility index'. PURPOSE: The purpose of this study was to evaluate the relationship between the cuff pulsatility index and invasively determined arterial pulsatility in patients with a left ventricular assist device. METHODS: Twenty-three patients with a left ventricular assist device with end-stage heart failure (six females: age = 65 ± 9 years; body mass index = 30.5 ± 3.7 kg m-2) were recruited for this study. Suprasystolic occlusions were performed on the upper arm of the patient's dominant side, from which the cuff pressure waveform was obtained. Arterial blood pressure was obtained from the radial artery on the contralateral arm. Measurements were obtained in triplicate. The relationship between the cuff pressure and arterial blood pressure waveforms was assessed in the frequency-domain using coherence analysis. A mixed-effects approach was used to assess the relationship between cuff pulsatility index and invasively determined arterial pulsatility (i.e. pulse pressure). RESULTS: The cuff pressure and arterial blood pressure waveforms demonstrated a high coherence up to the fifth harmonic of the cardiac frequency (heart rate). The cuff pulsatility index accurately tracked changes in arterial pulse pressure within a given patient across repeated measurements. CONCLUSIONS: The cuff pulsatility index shows promise as a non-invasive index for monitoring residual arterial pulsatility in patients with a left ventricular assist device across time.
- MeSH
- arterie patofyziologie MeSH
- asistovaná cirkulace přístrojové vybavení metody MeSH
- diagnostické techniky kardiovaskulární MeSH
- krevní tlak fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- podpůrné srdeční systémy * MeSH
- pulz metody MeSH
- pulzatilní průtok fyziologie MeSH
- reprodukovatelnost výsledků MeSH
- senioři MeSH
- srdeční selhání * patofyziologie terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: To explore the association between fetal umbilical and middle cerebral artery (MCA) Doppler abnormalities and outcome in late preterm pregnancies at risk of fetal growth restriction. METHODS: This was a prospective cohort study of singleton pregnancies at risk of fetal growth restriction at 32 + 0 to 36 + 6 weeks of gestation, enrolled in 33 European centers between 2017 and 2018, in which umbilical and fetal MCA Doppler velocimetry was performed. Pregnancies were considered at risk of fetal growth restriction if they had estimated fetal weight and/or abdominal circumference (AC) < 10th percentile, abnormal arterial Doppler and/or a fall in AC growth velocity of more than 40 percentile points from the 20-week scan. Composite adverse outcome comprised both immediate adverse birth outcome and major neonatal morbidity. Using a range of cut-off values, the association of MCA pulsatility index and umbilicocerebral ratio (UCR) with composite adverse outcome was explored. RESULTS: The study population comprised 856 women. There were two (0.2%) intrauterine deaths. Median gestational age at delivery was 38 (interquartile range (IQR), 37-39) weeks and birth weight was 2478 (IQR, 2140-2790) g. Compared with infants with normal outcome, those with composite adverse outcome (n = 93; 11%) were delivered at an earlier gestational age (36 vs 38 weeks) and had a lower birth weight (1900 vs 2540 g). The first Doppler observation of MCA pulsatility index < 5th percentile and UCR Z-score above gestational-age-specific thresholds (1.5 at 32-33 weeks and 1.0 at 34-36 weeks) had the highest relative risks (RR) for composite adverse outcome (RR 2.2 (95% CI, 1.5-3.2) and RR 2.0 (95% CI, 1.4-3.0), respectively). After adjustment for confounders, the association between UCR Z-score and composite adverse outcome remained significant, although gestational age at delivery and birth-weight Z-score had a stronger association. CONCLUSION: In this prospective multicenter study, signs of cerebral blood flow redistribution were found to be associated with adverse outcome in late preterm singleton pregnancies at risk of fetal growth restriction. Whether cerebral redistribution is a marker describing the severity of fetal growth restriction or an independent risk factor for adverse outcome remains unclear, and whether it is useful for clinical management can be answered only in a randomized trial. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.
- MeSH
- arteria cerebri media diagnostické zobrazování embryologie MeSH
- arteriae umbilicales diagnostické zobrazování embryologie MeSH
- dospělí MeSH
- gestační stáří MeSH
- hmotnost plodu MeSH
- hypotrofický novorozenec MeSH
- lidé MeSH
- narození mrtvého plodu MeSH
- narození živého dítěte MeSH
- novorozenec MeSH
- obvod pasu MeSH
- plod krevní zásobení diagnostické zobrazování patofyziologie MeSH
- porodní hmotnost MeSH
- prospektivní studie MeSH
- pulzatilní průtok MeSH
- referenční hodnoty MeSH
- reologie * MeSH
- růstová retardace plodu diagnostické zobrazování patofyziologie MeSH
- těhotenství MeSH
- ultrasonografie dopplerovská * MeSH
- ultrasonografie prenatální * MeSH
- vývoj plodu * MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- novorozenec MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
OBJECTIVES: To determine the pulsatility index (PI) in the fetal splenic vein, the main portal vein, the left portal vein, and the ductus venosus with respect to the presence or absence of intra-amniotic inflammation (IAI) in preterm prelabor rupture of membranes (PPROM). METHOD: Women with singleton pregnancies and PPROM, ranging in gestational age from 22+0 to 36+6 weeks, were included. Amniotic fluid samples were obtained by transabdominal amniocentesis and the amniotic fluid level of interleukin-6 (IL-6) was assessed by a point-of-care test. Doppler examination of the selected veins was performed, and the PI was assessed. IAI was defined as amniotic fluid levels of IL-6 ≥745 pg/mL. RESULTS: In total, 42 women were included. Fetuses with IAI compared with those without IAI exhibited a higher PI in the splenic vein (p = 0.005) and the main portal vein (p = 0.05). No differences were observed in the left portal vein PI (p = 0.36) and the ductus venosus PI (p = 0.98). CONCLUSION: IAI was associated with increased fetal splenic vein PI and main portal vein PI in PPROM. The absence of changes in the left portal vein PI and ductus venosus PI supports the local cause of the finding.
- MeSH
- chorioamnionitida diagnostické zobrazování etiologie metabolismus patofyziologie MeSH
- dospělí MeSH
- gestační stáří MeSH
- interleukin-6 analýza MeSH
- jaterní oběh * MeSH
- lidé MeSH
- plodová voda chemie MeSH
- předčasná porodní činnost diagnostické zobrazování etiologie metabolismus patofyziologie MeSH
- prospektivní studie MeSH
- pulzatilní průtok * MeSH
- rychlost toku krve MeSH
- těhotenství MeSH
- ultrasonografie dopplerovská barevná MeSH
- ultrasonografie prenatální metody MeSH
- vena lienalis diagnostické zobrazování patofyziologie MeSH
- vena portae diagnostické zobrazování patofyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
In the pulmonary circulation, resistive and compliant properties overlap in the same vessels. Resistance varies nonlinearly with pressure and flow; this relationship is driven by the elastic properties of the vessels. Linehan et al. correlated the mean pulmonary arterial pressure and mean flow with resistance using an original equation incorporating the distensibility of the pulmonary arteries. The goal of this study was to validate this equation in an in vivo porcine model. In vivo measurements were acquired in 6 pigs. The distensibility coefficient (DC) was measured by placing piezo-electric crystals around the pulmonary artery (PA). In addition to experiments under pulsatile conditions, a right ventricular (RV) bypass system was used to induce a continuous pulmonary flow state. The Linehan et al. equation was then used to predict the pressure from the flow under continuous flow conditions. The diameter-derived DC was 2.4%/mmHg (+/-0.4%), whereas the surface area-based DC was 4.1 %/mmHg (+/-0.1%). An increase in continuous flow was associated with a constant decrease in resistance, which correlated with the diameter-based DC (r=-0.8407, p=0.044) and the surface area-based DC (r=-0.8986, p=0.028). In contrast to the Linehan et al. equation, our results showed constant or even decreasing pressure as flow increased. Using a model of continuous pulmonary flow induced by an RV assist system, pulmonary pressure could not be predicted based on the flow using the Linehan et al. equation. Measurements of distensibility based on the diameter of the PA were inversely correlated with the resistance.
Mezi důležitou součást fyzikálního vyšetření dítěte patří zhodnocení pulzace periferních arterií a prokrvení periferie. Nezbytné je zároveň porovnání charakteru amplitudy pulsu na horních končetinách (palpací brachiálních, ev. radiálních arterií) a na dolních končetinách (palpací femorálních arterií). Při oslabení či opoždění pulsace na femorálních arteriích, pozorované v novorozeneckém či časném kojeneckém věku, musí být na prvním místě vyloučena srdeční vada – koarktace aorty. Absence pulsace femorálních arterií mohou zapříčinit i další patologie, ke kterým řadíme vrozené cévní malformace aortoiliacké oblasti, útlak cév extravaskulární masou (tumorem, cystou) a trombózy.
The assessment of peripheral arterial pulsation and peripheral perfusion is an important part of physical examination in infants. Itis also necessary to compare the character of the pulse amplitude on the upper limbs (palpation of the brachial or radial arteries)and on the lower limbs (palpation of the femoral arteries). If the pulsation of femoral arteries is weakened or delayed in neonatalperiod or in early infancy, a heart defect – coarctation of the aorta – has to be ruled out first. The absence of femoral artery pulsationmay also be caused by other pathologies, including congenital vascular malformations in the aortoiliac region, compressionof blood vessels by an extravascular mass (tumour, cyst) and thrombosis.
- MeSH
- arterie diagnostické zobrazování MeSH
- diferenciální diagnóza MeSH
- heparin aplikace a dávkování MeSH
- lidé MeSH
- novorozenec MeSH
- průchodnost cév * MeSH
- pulzatilní průtok * fyziologie MeSH
- trombolytická terapie MeSH
- trombóza diagnostické zobrazování etiologie terapie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- Publikační typ
- kazuistiky MeSH
INTRODUCTION: There is still a lack of organs for kidney transplantation. The aim of our experimental animal study was to improve the quality of the kidney grafts from donors after cardiac death (DCD) using immediate start of machine perfusion instead of perfusion based on hydrostatic pressure. METHODS: Ten rabbits were used as an experimental model. In group A, 5 kidneys after ischemic injury were perfused in situ using hydrostatic pressure. In group B, 5 kidneys were perfused in situ using machine pulsatile perfusion. After nephrectomy kidney parenchyma was histologically analyzed. We have evaluated the maximum perfusion flow rate, temperature drop rate, and degree of parenchymal injury. RESULTS: The flow rate in the group of machine-perfused animals (group B) was significantly higher than in the control group (group A), and temperature was significantly decreased in group B (P < .001). Qualitative histopathologic evaluation of the perfusion quality of the grafts was statistically significant, again in favor of machine perfusion in group B (P = .005). DISCUSSION: According to our results, the immediate start of machine perfusion is a superior method of kidney graft preservation in DCDs. All observed modalities were superior in the group with machine perfusion compared with usual clinical practice.
- MeSH
- dárci tkání MeSH
- králíci MeSH
- ledviny * MeSH
- modely nemocí na zvířatech MeSH
- nefrektomie MeSH
- odběr tkání a orgánů metody MeSH
- perfuze metody MeSH
- pulzatilní průtok MeSH
- smrt MeSH
- transplantace ledvin metody MeSH
- transplantáty MeSH
- uchovávání orgánů metody MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
