This study investigates the influence of varying degrees of stenosis on blood flow within elliptic arteries, emphasizing the critical role of artery shape in clinical evaluations as opposed to the commonly studied circular arteries. Unlike prior work, this research offers a precise definition of stenosis by incorporating the measured length, height, and position of the narrowing. Employing the non-Newtonian Williamson fluid model, we conducted comprehensive numerical simulations to examine blood flow through four distinct stenosis formations. The novelty of this work lies in its accurate modeling of stenosis and use of advanced mesh generation, combined with commercial software and the finite volume method, to capture detailed hemodynamic behavior. Visualized results, including pressure profiles, velocity line graphs, and streamlines, further underscore the distinctive flow dynamics shaped by the elliptic geometry. Key findings of the obtained results reveal that blood velocity peaks near the stenosis and drops significantly post-stenosis, with notable variations in flow patterns, energy loss, and pressure distribution across different stenosis types. Further, higher velocity of blood flow is observed in elliptic arteries in comparison with circular ones. In the area of the high corners of stenotic segments, the pressure profile reaches high values. As a result of the narrowing of the arterial cross-section, the varied time shows that the post-stenotic segment of the artery has a higher pressure than the pre-stenotic section. The varied time suggests that an axially symmetric profile will eventually be the norm for the flow within the arterial portion. These insights have profound implications for improving clinical diagnosis and treatment strategies for conditions related to stenosed elliptic arteries.
OBJECTIVES: Fabry disease (FD) is a rare X-linked lysosomal storage disorder with variable phenotypes, including neurological symptoms. These can be influenced by vascular impairment. Extracranial and transcranial vascular sonography is an effective and noninvasive method for measuring arterial structures and blood flow. The study aims to investigate cerebrovascular phenotype characteristics in FD patients compared to controls using neurosonology. METHODS: This is a single-center, cross-sectional study of 130 subjects-65 patients (38 females), with genetically confirmed FD, and 65 sex- and age-matched controls. Using ultrasonography, we measured structural and hemodynamic parameters, including distal common carotid artery intima-media thickness, inner vertebral artery diameter, resting blood flow velocity, pulsatility index, and cerebral vasoreactivity (CVR) in the middle cerebral artery. To assess differences between FD and controls and to identify factors influencing investigated outcomes, unadjusted and adjusted regression analyses were performed. RESULTS: In comparison to sex- and age-matched controls, FD patients displayed significantly increased carotid artery intima-media thickness (observed FD 0.69 ± 0.13 mm versus controls 0.63 ± 0.12 mm; Padj = .0014), vertebral artery diameter (observed FD 3.59 ± 0.35 mm versus controls 3.38 ± 0.33 mm; Padj = .0002), middle cerebral artery pulsatility index (observed FD 0.98 ± 0.19 versus controls 0.87 ± 0.11; Padj < .0001), and significantly decreased CVR (observed FD 1.21 ± 0.49 versus controls 1.35 ± 0.38; Padj = .0409), when adjusted by age, BMI, and sex. Additionally, FD patients had significantly more variable CVR (0.48 ± 0.25 versus 0.21 ± 0.14; Padj < .0001). CONCLUSIONS: Our results suggest the presence of multiple vascular abnormalities and changes in hemodynamic parameters of cerebral arteries in patients with FD.
- Klíčová slova
- Fabry disease, breath-holding index, cerebral blood flow, cerebral vasoreactivity, intima-media thickness, pulsatility index,
- MeSH
- Fabryho nemoc * diagnostické zobrazování MeSH
- hemodynamika fyziologie MeSH
- intimomediální šíře tepenné stěny MeSH
- lidé MeSH
- mozkový krevní oběh fyziologie MeSH
- průřezové studie MeSH
- rychlost toku krve fyziologie MeSH
- ultrasonografie dopplerovská transkraniální metody MeSH
- ultrasonografie MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Atherosclerosis and coronary artery disease (CAD) are a common condition and cause of death in the elderly population. There are difficulties with risk assessment in the elderly as the objectification of their symptomatic status can be challenging due to neuromuscular weakness, physical deconditioning or neurological, orthopaedic, peripheral vascular, or respiratory limitations. Non-invasive coronary artery velocity assessment by Doppler method at rest could be helpful in the elderly population. To evaluate the prognostic role of coronary artery ultrasound assessment in a non-selected elderly population in everyday clinical practice. METHODS: One hundred forty-five patients, aged ≥75years (99 women; 80 ± 4 years), formed the study group. Left coronary artery flows were scanned in addition to conventional echocardiography. During a median follow-up of 26 months, 16 deaths and 2 non-fatal MI occurred. RESULTS: In multivariable analysis, maximal coronary velocity was the only independent predictor for mortality (heart rate [HR]: 1.02, 95%, CI: 1.01-1.04, p < .0005) and for mortality/MI (HR: 1.02, 95%, CI: 1.01-1.03, p < .0001). The value of 110 cm/s maximal coronary flow velocity (CFL) in the proximal segments of left arteries was the best predictor for death, sensitivity 50%, specificity 90%, p < .005. The annual mortality rate was 16.6% persons/year for patients with elevated CFL ≥110 cm/s. The value 81 cm/s was the best predictor for death/MI, sensitivity 61%, specificity 80%, p < .0005; annual mortality rate was 11.2% persons/year for patients with elevated CFL ≥81 cm/s (p < .0001). CONCLUSION: Doppler CFL scanning during routine echocardiography is a feasible and valuable tool for assessment of short-term prognosis in elderly patients.
- Klíčová slova
- Echocardiography, coronary flow: coronary Doppler, elderly, outcome,
- MeSH
- dopplerovská echokardiografie * metody MeSH
- echokardiografie MeSH
- koronární cirkulace fyziologie MeSH
- lidé MeSH
- nemoci koronárních tepen * MeSH
- prognóza MeSH
- rychlost toku krve fyziologie MeSH
- senioři MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
PURPOSE: The aim of our study was to acquire non-invasive data from coronary flow velocity profiles during exercise in groups of healthy subjects and of patients with arterial hypertension. MATERIAL AND METHODS: We enrolled 83 patients into two groups: (1) 35 non-selected consecutive healthy subjects; (2) 25 consecutive patients with arterial hypertension. All the patients performed supine bicycle symptoms-limited tests. Throughout exercise the diastolic peaks of coronary flow velocity in LAD were recorded. Coronary flow velocity reserve (CFVR) was calculated off-line. Profiles of coronary artery velocity were acquired for all groups. The coronary artery flow parameters investigated were comparable in healthy and hypertensive patients at every stage. RESULTS: The average diastolic velocities were 54.8 ± 12.9 vs. 51.8 ± 12.2 cm/s, at 50 W; 69.2 ± 17.1 vs 64.4 ± 19.1 cm/s at 75 W; 70.7 ± 16.4 vs. 76.1 ± 19.0 cm/s at 100 W; 80.0 ± 16.0 vs. 72.9 ± 16.1 cm/s at 125 W; 83.7 ± 12.2 vs. 81.4 ± 17.0 at 150 W, p- non-significant, respectively. On average, the healthy group reached CFVR > 2.0 at a heart rate of 110-120 beats/min at 75 W. During supine bicycle exercise, healthy subjects and patients with arterial hypertension have a similar coronary artery flow velocity profile. CONCLUSION: The routine exercise echocardiography test can feasibly be supplemented with the additional measurement of coronary flow velocity during routine supine exercise stress tests, as the normal range of CFVR is reached before submaximal heart rate.
- Klíčová slova
- Coronary flow reserve, arterial hypertension, coronary velocity, exercise echocardiography, transthoracic coronary artery echo,
- MeSH
- echokardiografie MeSH
- hypertenze * MeSH
- koronární cévy * diagnostické zobrazování MeSH
- koronární cirkulace fyziologie MeSH
- lidé MeSH
- rychlost toku krve fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Diabetes mellitus 2 (DM2) is the seventh cause of death worldwide. One of the reasons is late diagnosis of vascular damage. Pulse wave velocity (PWV) has become an independent marker of arterial stiffness and cardiovascular risk. Moreover, the previous studies have shown the importance of beat-to-beat PWV measurement due to its variability among the heart cycle. However, variability of PWV (PWVv) of the whole body hasn't been examined yet. We have studied a group of DM II and heathy volunteers, to investigate the beat-to-beat mean PWV (PWVm) and PWVv in the different body positions. PWV of left lower and upper extremities were measured in DM2 (7 m/8 f, age 68+/-10 years, BP 158/90+/-19/9 mm Hg) and healthy controls (5 m/6 f, age 23+/-2 years, BP 117/76+/-9/5 mm Hg). Volunteers were lying in the resting position and of head-up-tilt in 45° (HUT) for 6 min. PWVv was evaluated as a mean power spectrum in the frequency bands LF and HF (0.04-0.15 Hz, 0.15-0.5 Hz). Resting PWVm of upper extremity was higher in DM2. HUT increased lower extremity PWVm only in DM2. Extremities PWVm ratio was significantly lower in DM2 during HUT compared to controls. LF and HF PWVv had the same response to HUT. Resting PWVv was higher in DM2. Lower extremity PWVv increased during HUT in both groups. PWVm and PWVv in DM2 differed between extremities and were significantly influenced by postural changes due to hydrostatic pressure. Increased resting PWVm and PWVv in DM2 is a marker of increased arterial stiffness.
- MeSH
- analýza pulzové vlny metody MeSH
- diabetes mellitus 2. typu metabolismus patologie MeSH
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- nemoci cév diagnóza metabolismus patologie MeSH
- postura těla fyziologie MeSH
- rychlost toku krve fyziologie MeSH
- senioři MeSH
- srdeční frekvence fyziologie MeSH
- studie případů a kontrol MeSH
- tuhost cévní stěny MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Beneficial effects of sesame lignans, especially antioxidative effects, have been widely reported; however, its potential effects on autonomic nerves have not yet been investigated. Therefore, the current study aimed to investigate the effect of sesame lignans on the autonomic nervous system. The sympathetic nerve activity in rat skeletal muscle was measured using electrophysiological approaches, with blood flow determined using the laser Doppler method. Sesame lignans were administered intragastrically at 2 and 20 mg/kg, and after 60 min, the sympathetic nerve activity was observed to increase by 45.2% and 66.1%, respectively. A significant increase in blood flow (39.6%) was also observed for the 20-mg/kg dose when measured at 55 min after administration. These sympathomimetic effects were completely prevented by subdiaphragmatic vagotomy, and the increase in blood flow was eliminated in the presence of the beta2-adrenergic receptor inhibitor butoxamine. Thus, it is proposed that sesame lignans can increase the blood flow of skeletal muscle, possibly by exciting sympathetic nerve activity through the afferent vagal nerve.
- MeSH
- hemodynamika účinky léků fyziologie MeSH
- kosterní svaly krevní zásobení účinky léků fyziologie MeSH
- krysa rodu Rattus MeSH
- lignany izolace a purifikace farmakologie MeSH
- rychlost toku krve účinky léků fyziologie MeSH
- Sesamum * MeSH
- sympatická vlákna postgangliová účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- lignany MeSH
We investigated the cerebral autoregulation (CA) dynamics parameter phase and gain change when exposed to a longlasting motor task. 25 healthy subjects (mean age ± SE, 38±2.6 years, 13 females) underwent simultaneous recordings of spontaneous fluctuations in blood pressure (BP), cerebral blood flow velocity (CBFV), and end-tidal CO(2) (ETCO(2)) over 5 min of rest followed by 5 min of left elbow flexion at a frequency of 1 Hz. Tansfer function gain and phase between BP and CBFV were assessed in the frequency ranges of very low frequencies (VLF, 0.02-0.07 Hz), low frequencies (LF, 0.07-0.15), and high frequencies (HF, >0.15). CBFV increased on both sides rapidly to maintain an elevated steady state until movement stopped. Cerebrovascular resistance fell on the right side (rest 1.35±0.06, movement 1.28±0.06, p<0.01), LF gain decreased from baseline (right side 0.97±0.07 %/mm Hg, left 1.01±0.09) to movement epoch (right 0.73±0.08, left 0.76±0.06, p
- MeSH
- dospělí MeSH
- krevní tlak fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- loket fyziologie MeSH
- mozkový krevní oběh fyziologie MeSH
- psychomotorický výkon fyziologie MeSH
- rychlost toku krve fyziologie MeSH
- srdeční frekvence fyziologie MeSH
- ultrasonografie dopplerovská transkraniální metody MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The role of the glycocalyx of arterial resistance vessels in regulating blood flow in vivo is not fully understood. Therefore, the effect of glycocalyx damage using two separate compounds, hyaluronidase and N-Formylmethionyl-leucyl-phenylalanine (fMLP), was evaluated in the iliac artery vascular bed of the anaesthetised pig. Blood flow and pressure were measured in the iliac, an adjustable snare was applied to the iliac above the pressure and flow measurement site to induce step decreases (3 occlusions at 3-4 min intervals were performed for each infusion) in blood flow, and hence iliac pressure, and vascular conductance (flow/pressure) was calculated. Saline, hyaluronidase (14 and 28 microg/ml/min), and fMLP (1 microM/min) were infused separately, downstream of the adjustable snare and their effect on arterial conductance assessed. Hyaluronidase at the higher infusion rate and fMLP both caused a reduction in arterial conductance, and hence an increase in blood flow resistance. In conclusion, the results show that glycocalyx damage causes an increase in resistance to blood flow in the iliac artery vascular bed.
BACKGROUND: Takotsubo cardiomyopathy (TC) aetiology has not been completely understood yet. One proposed pathogenic mechanism was coronary microvascular dysfunction (MVD). This study compared coronary flow and myocardial perfusion in patients with TC, microvascular angina (MVA), and a control group (CG). METHODS: Out of 42 consecutive patients presented to our centre with TC from 2013 to 2017; we retrospectively selected 27 patients. We compared them with a sex- and age-matched group of 27 MVA cases and 27 patients with normal coronary arteries (CG). The flow was evaluated in the three coronary arteries as TIMI flow and TIMI frame count (TFC). Myocardial perfusion was studied with Blush-Score and Quantitative Blush Evaluator (QuBE). RESULTS: TFC, in TC, revealed flow impairment in the three arteries compared to the CG (left anterior descending artery (LAD): 22 ± 8, 15 ± 4; p = 0.001) (right coronary artery: 12 ± 4, 10 ± 3; p = 0,025) (left circumflex: 14 ± 4, CG 11 ± 3; p = 0,006). QuBE showed myocardial perfusion impairment in the LAD territory in TC comparing with both the CG (8,9 (7,2-11,5) versus 11,4 (10-15,7); p = 0,008) and the MVA group (8,9 (7,2-11,5) versus 13,5 (10-16); p = 0,006). CONCLUSIONS: Our study confirmed that coronary flow is impaired in TC, reflecting a MVD. Myocardial perfusion defect was detected only in the LAD area.
- MeSH
- echokardiografie metody MeSH
- infarkt myokardu patofyziologie MeSH
- koronární angiografie metody MeSH
- koronární cévy patofyziologie MeSH
- koronární cirkulace fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikrocévy patofyziologie MeSH
- retrospektivní studie MeSH
- rychlost toku krve fyziologie MeSH
- senioři MeSH
- takotsubo kardiomyopatie patofyziologie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is a method used for the treatment most severe cases of decompensated heart failure. The purpose of this study was to evaluate the risk of the formation of microembolisms during VA-ECMO-based therapy. Heart failure was induced with simultaneous detection of microembolisms and the measurement of blood flow rate in the common carotid artery (CCA) without VA-ECMO (0 l/min) and at the VA-ECMO blood flow rate of 1, 2, 3 and 4 l/min. If embolisms for VA-ECMO 0 l/min and the individual regimes for VA-ECMO 1, 2, 3, 4 l/min are compared, a higher VA-ECMO flow rate is accompanied by a higher number of microembolisms. The final microembolism value at 16 min was for the VA-ECMO flow rate of 0 l/min 0.0 (0, 1), VA-ECMO l/min 7.5 (4, 19), VA-ECMO 2 l/min 12.5 (4, 26), VA-ECMO 3 l/min, 21.0 (18, 57) and VA-ECMO 4 l/min, 27.5 (21, 64). Such a comparison is statistically significant if VA-ECMO 0 vs. 4 l/min p<0.0001, 0 vs. 3 l/min p<0.01 and 1 vs. 4 l/min p<0.01 are compared. The results confirm that high VA-ECMO flow rates pose a risk with regards to the formation of a significantly higher number of microemboli in the blood circulation and that an increase in blood flow rates in the CCA corresponds to changes in the VA-ECMO flow rates.
- MeSH
- akutní nemoc MeSH
- arteria carotis communis diagnostické zobrazování patofyziologie MeSH
- embolie diagnostické zobrazování patofyziologie MeSH
- mikrocirkulace fyziologie MeSH
- mimotělní membránová oxygenace škodlivé účinky trendy MeSH
- modely nemocí na zvířatech * MeSH
- prasata MeSH
- rychlost toku krve fyziologie MeSH
- srdeční selhání diagnostické zobrazování patofyziologie terapie MeSH
- ultrasonografie dopplerovská metody trendy MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
