Accurate quantitative measurements of brachial artery cross-sectional vascular area and vascular volume elastic modulus using automated oscillometric measurements: comparison with brachial artery ultrasound

3-Fr steerable microcatheter system via the upper limb artery in RADPLAT for right maxillary cancer

BACKGROUND

To evaluate the efficacy of a catheter system using a 3-Fr sheath with a steerable microcatheter through right upper limb artery access for superselective intra-arterial cisplatin infusion and concomitant radiotherapy (RADPLAT) to treat right maxillary sinus squamous cell carcinoma (MS-SCC).

MATERIAL AND METHODS

We retrospectively studied 46 sessions in eight patients treated between November 2020 and February 2023 using the catheter system briefly described below. A 3-Fr sheath was inserted into the distal radial, conventional radial, or brachial arteries. A coaxial catheter system with a 2.9-Fr steerable microcatheter and a 1.9-Fr microcatheter was advanced into the brachiocephalic artery. The right common carotid artery was selected by bending the tip of the steerable microcatheter. Coil embolization and intra-arterial cisplatin infusion after selecting each external carotid artery branch were achieved using this catheter system.

RESULTS

Cisplatin infusion and coil embolization were successful in all sessions. Arterial occlusion at the sheath insertion sites was found in 29.4% (5/17) of the distal radial arteries and 33.3% (3/9) of the conventional radial arteries. No other major complications were observed during the procedure.

CONCLUSION

Using a 3-Fr catheter system with a steerable microcatheter through right upper limb artery access is a feasible method for RADPLAT in treating right MS-SCC.

Volume Elastic Modulus, Vascular Function, and Vascular Structure in Patients with Cardiovascular Risk Factors

Aims: Volume elastic modulus (V _E ), an index of arterial elasticity, and arterial diameter of the brachial artery can be automatically measured by a newly developed oscillometric device. We investigated the associations of V _E with flow-mediated vasodilation (FMD), an index of endothelium-dependent vasodilation, nitroglycerine-induced vasodilation (NID), an index of endothelium-independent vasodilation, and intima-media thickness (IMT) of the brachial artery and association of oscillometrically measured brachial artery diameter with ultrasonographically measured brachial artery diameter in patients with cardiovascular risk factors.

Methods: Oscillometric measurements of V _E and brachial artery diameter and ultrasound measurements of brachial artery diameter, FMD, NID, and IMT of the brachial artery were performed in 50 patients with cardiovascular risk factors.

Results: The mean values were 2.1±0.4 mmHg/% for V _E , 0.31±0.05 mm for brachial IMT, 4.48±0.70 mm for oscillometric brachial artery diameter, and 4.30±0.55 mm for ultrasound brachial artery diameter. V _E significantly correlated with brachial IMT (r=0.51, P ＜0.001), whereas there was no significant correlation of V _E with FMD (r=-0.08, P =0.58) or NID (r=0.07, P =0.61). Multivariate analysis revealed that V _E was significantly associated with brachial IMT (β=0.33, P =0.04). Oscillometric brachial artery diameter significantly correlated with ultrasound brachial artery diameter (r=0.79, P ＜0.001). The Bland-Altman plot showed good agreement between oscillometric brachial artery diameter and ultrasound brachial artery diameter (mean difference, -0.17 mm; limits of agreement, -1.03 mm to 0.69 mm).

Conclusions: In patients with cardiovascular risk factors, V _E may represent atherosclerotic structural alterations of the vascular wall but not vascular function. The accuracy of oscillometric measurement of brachial artery diameter is acceptable.

Hemodynamic modeling of the circle of Willis reveals unanticipated functions during cardiovascular stress

The circle of Willis (CW) allows blood to be redistributed throughout the brain during local ischemia; however, it is unlikely that the anatomic persistence of the CW across mammalian species is driven by natural selection of individuals with resistance to cerebrovascular disease typically occurring in elderly humans. To determine the effects of communicating arteries (CoAs) in the CW on cerebral pulse wave propagation and blood flow velocity, we simulated young, active adult humans undergoing different states of cardiovascular stress (i.e., fear and aerobic exercise) using discrete transmission line segments with stress-adjusted cardiac output, peripheral resistance, and arterial compliance. Phase delays between vertebrobasilar and carotid pulses allowed bidirectional shunting through CoAs: both posteroanterior shunting before the peak of the pulse waveform and anteroposterior shunting after internal carotid pressure exceeded posterior cerebral pressure. Relative to an absent CW without intact CoAs, the complete CW blunted anterior pulse waveforms, although limited to 3% and 6% reductions in peak pressure and pulse pressure, respectively. Systolic rate of change in pressure (i.e., ∂P/∂t) was reduced 15%-24% in the anterior vasculature and increased 23%-41% in the posterior vasculature. Bidirectional shunting through posterior CoAs was amplified during cardiovascular stress and increased peak velocity by 25%, diastolic-to-systolic velocity range by 44%, and blood velocity acceleration by 134% in the vertebrobasilar arteries. This effect may facilitate stress-related increases in blood flow to the cerebellum (improving motor coordination) and reticular-activating system (enhancing attention and focus) via a nitric oxide-dependent mechanism, thereby improving survival in fight-or-flight situations.NEW & NOTEWORTHY Hemodynamic modeling reveals potential evolutionary benefits of the intact circle of Willis (CW) during fear and aerobic exercise. The CW equalizes pulse waveforms due to bidirectional shunting of blood flow through communicating arteries, which boosts vertebrobasilar blood flow velocity and acceleration. These phenomena may enhance perfusion of the brainstem and cerebellum via nitric oxide-mediated vasodilation, improving performance of the reticular-activating system and motor coordination in survival situations.

Ultrasound-guided arterial catheterization

Ultrasonography facilitates arterial catheterization compared to traditional palpation techniques, especially in small arteries. For successful catheterization without complications, practitioners should be familiar with the anatomic characteristics of the artery and ultrasound-guided techniques. There are two approaches for ultrasound-guided arterial catheterization: the short-axis view out-of-plane approach and the long-axis view in-plane approach. There are several modified techniques and tips to facilitate ultrasound-guided arterial catheterization. This review deals with the anatomy relevant to arterial catheterization, several methods to improve success rates, and decrease complications associated with arterial catheterization.

Noninvasive Measurement of Time-Varying Arterial Wall Elastance Using a Single-Frequency Vibration Approach

The arterial wall elastance is an important indicator of arterial stiffness and a kind of manifestation associated with vessel-related disease. The time-varying arterial wall elastances can be measured using a multiple-frequency vibration approach according to the Voigt and Maxwell model. However, such a method needs extensive calculation time and its operating steps are very complex. Thus, the aim of this study is to propose a simple and easy method for assessing the time-varying arterial wall elastances with the single-frequency vibration approach. This method was developed according to the simplified Voigt and Maxwell model. Thus, the arterial wall elastance measured using this method was compared with the elastance measured using the multiple-frequency vibration approach. In the single-frequency vibration approach, a moving probe of a vibrator was induced with a radial displacement of 0.15 mm and a 40 Hz frequency. The tip of the probe directly contacted the wall of a superficial radial artery, resulting in the arterial wall moving 0.15 mm radially. A force sensor attached to the probe was used to detect the reactive force exerted by the radial arterial wall. According to Voigt and Maxwell model, the wall elastance (E_single) was calculated from the ratio of the measured reactive force to the peak deflection of the displacement. The wall elastances (E_multiple) measured by the multiple-frequency vibration approach were used as the reference to validate the performance of the single-frequency approach. Twenty-eight healthy subjects were recruited in the study. Individual wall elastances of the radial artery were determined with the multiple-frequency and the single-frequency approaches at room temperature (25 °C), after 5 min of cold stress (4 °C), and after 5 min of hot stress (42 °C). We found that the time-varying E_single curves were very close to the time-varying E_multiple curves. Meanwhile, there was a regression line (E_single = 0.019 + 0.91 E_multiple, standard error of the estimate (SEE) = 0.0295, p < 0.0001) with a high correlation coefficient (0.995) between E_single and E_multiple. Furthermore, from the Bland-Altman plot, good precision and agreement between the two approaches were demonstrated. In summary, the proposed approach with a single-frequency vibrator and a force sensor showed its feasibility for measuring time-varying wall elastances.

A systematic review and individual patient data meta-analysis of heart failure as a rare complication of traumatic arteriovenous fistulas

OBJECTIVE

Traumatic arteriovenous fistulas (AVFs) are rare. The vast majority occur secondary to penetrating injuries. High-output cardiac failure is a well-recognized serious complication of AVFs, associated with high morbidity and mortality. The objective of the present study was to identify predictors of heart failure (HF) in patients with traumatic AVF.

METHODS

Both PubMed/MEDLINE (Ovid) and CINAHL were searched (up to June 2019) for studies reporting individual patient data on the clinical and demographic characteristics of patients with AVF secondary to penetrating trauma. Exclusion criteria were age <18 years, no specification of symptoms, a cranial, spinal, or cardiac AVF location, and an iatrogenic mechanism of injury. The present study was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines.

RESULTS

A total of 274 AVF patients from 15 case series and 177 case reports were included. The median age at presentation was 32 years (interquartile range, 24-43 years), 90% were men. The most frequent mechanisms of injury were stab wounds (43%) and gunshot wounds (32%). The AVF location was the abdomen (n = 86; 31%), lower limb (n = 79; 29%), neck (n = 61; 22%), thorax (n = 38; 14%), and upper limb (n = 10; 4%). Of the 274 patients, 35 (13%) had presented with HF and 239 (87%) with other symptoms. The risk of HF increased with an increased feeding artery diameter (P < .001). On univariate analysis, HF was significantly associated with a longer median time from injury to presentation with AVF (11.2 years vs 0.1 years; P < .001), older median age at presentation (43 years vs 31 years; P = .002), involvement of a large feeding artery (ie, aorta, pulmonary artery, subclavian artery, external iliac artery; 40% vs 13%; P < .001), shrapnel injuries (11% vs 2%; P = .011), and injuries to the trunk or lower limb (94% vs 71%; P = .004). After adjusting for clinical and demographic patient characteristics, involvement of a large feeding artery (odds ratio, 3.25; 95% confidence interval, 1.26-8.42; P = .015) and every 6 years of delay to presentation (odds ratio, 1.30; 95% confidence interval, 1.03-1.63; P = .026) remained independent predictors for HF.

CONCLUSIONS

HF occurs in a small but important fraction of traumatic AVF patients and develops after highly variable latency periods. Large feeding arteries and delayed presentation independently predicted HF in this cohort.

Modelling Dynamically Re-Sizeable Electrodes (DRE) for Targeted Transcutaneous Measurements in Impedance Plethysmography

Impedance plethysmography of extremities typically involves band electrodes around limbs to monitor changes in blood volume. This often causes monitored blood variations to only generate minuscule impedance values relative to the measured baseline, attributed to the tissue surrounding the artery or vein of interest. Smaller, ECG type electrodes can provide a larger signal, however their output is very easily affected by the placement of the electrodes relative to the targeted vasculature. This paper presents a novel method to adjust the active surface of electrodes, introducing Dynamically Re-sizeable Electrodes (DRE), to only target the exact area of interest, forming localised electrodes, without having to manually re-position them. Elongated rectangular electrodes were partitioned into smaller electrode segments, interconnected through custom circuitry. For the development and assessment of the DRE system, work was carried out both experimentally in-vitro on gelatine phantoms using custom switching circuits and through finite element modelling (FEM) simulations in COMSOL. A scanning sequence made use of DRE in single segment variable tetra-pole (SSVT) mode proved capable to identify the transcutaneous location of the blood vessel of interest and the specific electrode segments located in its vicinity. Impedance measurements were then taken using these segments connected to form localised electrodes only placed over the targeted vessel. The resulting localised electrodes exhibited up to [Formula: see text] increased sensitivity to blood variations relative to larger electrodes.

Feasibility of in-vivo estimation of the brachial artery area-pressure relation from CINE and real-time MRI during upper arm cuff inflations

OBJECTIVE

We investigate the basic feasibility of estimating the brachial artery area-pressure relationship from MRI data obtained during pressure cuff inflations in-vivo.

METHODS

We acquired cross-sectional real-time MR images and cardiac-gated CINE MR images from the upper arm of a single male subject at rest during supra-systolic pressure cuff inflations and deflations. We estimate from the MR images the lumen area changes of the brachial artery, and, simultaneously, from the cuff pressure the systemic blood pressure of the subject. We reconstruct the area-pressure curve from two real-time and three CINE independent measurements.

RESULTS

The area-pressure curve can be reconstructed, and it is plausible and appears largely consistent with the literature using other methods.

CONCLUSION

MR imaging during pressure cuff inflations is an easy to use, non-invasive candidate method to estimate the brachial artery pressure-area curve.

Insights into oscillometry: An Experimental Study for Improvement of Cuff-Based Blood Pressure Measurement Technology

Non-invasive blood pressure (BP) measurements are usually performed by means of an empirical interpretation of arterial oscillations recorded via cuff based oscillometic methods. Extensive effort has been put into development of a theoretical treatment of oscillometry aiming at more accurate BP estimations and measurement of additional hemodynamic parameters. However, oscillometry is still basically a heuristic method for BP inference.This study introduces an experimental setup and discusses experimental results to improve understanding of cuff characteristics and the process by which oscillometric signals are produced, with the aim of improving cuff-based non-invasive BP measurement technology relevant in clinical practice. The work focuses on mechanical simulations of arm volume pulsations in cuff pressure signals. The effects of air compression within the cuff and the influence of viscoelastic properties of exterior cuff material are also investigated. Additionally, arm volume changes and compressibility of arm tissue due to external cuff pressure were studied with an MRI system. Our results reveal novel insights into oscillometry and enable understanding of transducer design for cuffs including the importance of viscoelastic material properties and effects of cuff inflation on arm tissue.

NOVEL METHOD FOR ASSESSING ARTERIAL STIFFNESS BASED ON OSCILLOMETRIC BLOOD PRESSURE MEASUREMENT

Arterial stiffness is a major contributor to cardiovascular diseases. The aim of this study is to explore the physiological significance of the brachial mechanical parameters, which could be estimated from oscillometric blood pressure (BP) measurement, and investigate on the potential of these arterial parameters as an index of arterial stiffness. The mechanical characteristics of brachial artery were modeled based on the collapsible tube theory, which includes two important parameters to describe the compliance of brachial artery. After the model validation, the arterial parameters were estimated from the measured oscillometric envelope of 56 subjects by solving an inverse problem. The physiological significance of these parameters was explored by analyzing their association with pulse wave velocity (PWV) as well as with the BP. Arterial compliance parameters were successfully estimated from the envelope of the oscillometric pulse wave in the BP measurement. The parameters were found to be linearly associated with age, PWV, and BP. These results suggest that our method may provide a potential approach to assess arterial compliance based on oscillometric measurement of BP.

Evolution and Development of the Atrial Septum

The complete division of the atrial cavity by a septum, resulting in a left and right atrium, is found in many amphibians and all amniotes (reptiles, birds, and mammals). Surprisingly, it is only in eutherian, or placental, mammals that full atrial septation necessitates addition from a second septum. The high incidence of incomplete closure of the atrial septum in human, so-called probe patency, suggests this manner of closure is inefficient. We review the evolution and development of the atrial septum to understand the peculiar means of forming the atrial septum in eutherian mammals. The most primitive atrial septum is found in lungfishes and comprises a myocardial component with a mesenchymal cap on its leading edge, reminiscent to the primary atrial septum of embryonic mammals before closure of the primary foramen. In reptiles, birds, and mammals, the primary foramen is closed by the mesenchymal tissues of the atrioventricular cushions, the dorsal mesenchymal protrusion, and the mesenchymal cap. These tissues are also found in lungfishes. The closure of the primary foramen is preceded by the development of secondary perforations in the septal myocardium. In all amniotes, with the exception of eutherian mammals, the secondary perforations do not coalesce to a secondary foramen. Instead, the secondary perforations persist and are sealed by myocardial and endocardial growth after birth or hatching. We suggest that the error-prone secondary foramen allows large volumes of oxygen-rich blood to reach the cardiac left side, needed to sustain the growth of the extraordinary large offspring that characterizes eutherian mammals. Anat Rec, 302:32-48, 2019. © 2018 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

A Novel Minimally Occlusive Cuff Method Utilizing Ultrasound Vascular Imaging for Stress-Free Blood Pressure Measurement: A-Proof-of-Concept Study

OBJECTIVE

Occlusive cuff inflation in ambulatory blood pressure (BP) monitoring disturbs the daily life of the user and affects efficacy of monitoring. To overcome this limitation, we have developed a novel minimally occlusive cuff method for stress-free measurement of BP. This study aimed to experimentally evaluate the reliability of this method.

METHODS

In this method, a thin plate-type ultrasound probe placed between the cuff and the skin is used to measure the ultrasonic dimension of the artery. Analyzing the arterial dimension and the cuff pressure measured during mild cuff inflation (cuff pressure <50 mmHg) allows estimation of systolic BP (SBP_e) and diastolic BP (DBP_e). We evaluated this method in six anesthetized dogs by attaching the cuff with the probe to the right thigh to get SBP_e and DBP_e. We measured reference SBP and DBP using an intra-arterial catheter and determined the pulse arrival time (PAT), commonly employed in cuffless BP monitoring. BP was perturbed by infusing noradrenaline or nitroprusside.

RESULTS

DBP_e correlated tightly with DBP with a coefficient of determination (R²) of 0.85 ± 0.08, and predicted DBP with a mean ± standard deviation of error of 3.9 ± 7.9 mmHg after one-time calibration. Reciprocal of PAT correlated poorly with DBP (R² = 0.49 ± 0.17), and predicted DBP less accurately than this method. SBP_e correlated well with SBP (R² = 0.78 ± 0.08).

CONCLUSION

This method reliably tracks BP changes without occlusive cuff inflation. Once calibrated, this method measures DBP accurately.

SIGNIFICANCE

This method has the potential for stress-free BP measurement in ambulatory BP monitoring.

Elastin microfibril interface-located protein 1, transforming growth factor beta, and implications on cardiovascular complications

Elastin microfibril interface-located protein 1 (EMILIN1), a glycoprotein, is associated with elastin in the extracellular matrix (ECM) of arteries, lymph vasculature, and other tissues. EMILIN1 particularly has a niche role in elastin fiber biogenesis (elastogenesis) by aiding with the fusion of elastin fibers, rendering them more ordered. In addition to elastogenesis, EMILIN1 has been shown to have roles in maintenance of vascular cell morphology, smooth muscle cell adhesion to elastic fibers, and transforming growth factor (TGFβ) regulation, by inhibiting TGFβ activation via blocking the proteolytic production of the latency-associated peptide/active TGFβ complex. The increased TGFβ signaling induced during EMILIN1 deficiency alters TGFβ activity, resulting in vascular smooth muscle cell growth and vascular remodeling. The increasing systemic blood pressure associated with TGFβ signaling may be closely linked to the activity of other mediators that affect cardiovascular homeostasis, such as angiotensin II. The increase in prevalence of hypertension and other cardiovascular diseases in other disease states likely involve a complex activation of TGFβ signaling and ECM dysfunction. Thus, the interaction of TGFβ and ECM components appears to be integrative involving both structural alterations to vessels through EMILIN1 and changes in TGFβ signaling processes. This review summarizes the current knowledge on the EMILIN1-TGFβ relationship; the specific roles of EMILIN1 and TGFβ in blood pressure regulation, their synergistic interaction, and in particular the role of TGFβ (in conjunction with ECM proteins) in other disease states altering cardiovascular homeostasis.

Anatomical and Functional Estimations of Brachial Artery Diameter and Elasticity Using Oscillometric Measurements with a Quantitative Approach

Noninvasive vascular function measurement plays an important role in detecting early stages of atherosclerosis and in evaluating therapeutic responses. In this regard, recently, new vascular function measurements have been developed. These new measurements have been used to evaluate vascular function in coronary arteries, large aortic arteries, or peripheral arteries. Increasing vascular diameter represents vascular remodeling related to atherosclerosis. Attenuated vascular elasticity may be a reliable marker for atherosclerotic risk assessment. However, previous measurements for vascular diameter and vascular elasticity have been complex, operator-dependent, or invasive. Therefore, simple and reliable approaches have been sought. We recently developed a new automated oscillometric method to measure the estimated area (eA) of a brachial artery and its volume elastic modulus (VE). In this review, we further report on this new measurement and other vascular measurements. We report on the reliability of the new automated oscillometric measurement of eA and VE. Based on our findings, this measurement technique should be a reliable approach, and this modality may have practical application to automatically assess muscular artery diameter and elasticity in clinical or epidemiological settings. In this review, we report the characteristics of our new oscillometric measurements and other related vascular function measurements.

Volume elastic modulus of the brachial artery and coronary artery stenosis in patients with suspected stable coronary artery disease

This study aimed to examine the association between the non-invasive measurement of the brachial artery volume elastic modulus (V E), an index of arterial stiffness, and the presence of coronary artery stenosis in patients with suspected stable coronary artery disease (CAD). A total of 135 patients with suspected stable CAD (87 men, mean age, 64 ± 12 years) underwent oscillometric measurement of the brachial artery to obtain V E. Coronary angiography was thereafter carried out to diagnose CAD, defined as having ≥75 % stenosis in the epicardial coronary arteries. V E was significantly higher in patients with CAD (1.94 ± 0.34 mmHg/%) than in those without CAD (1.71 ± 0.35 mmHg/%, P < 0.001). In multiple logistic regression analysis, V E was an independent predictor for the presence of CAD (odds ratio 1.19 per 0.1 mmHg/% increase, 95 % CI 1.04-1.51) even after adjusting for multiple potential confounders including the Framingham risk score (FRS). The area under the curve of the receiver operating characteristic curve analysis for discriminating CAD increased significantly after the addition of V E to the FRS (from 0.75 to 0.81, P = 0.034). The category-free net reclassification improvement and the integrated discrimination improvement by adding V E to the FRS were 0.476 (95 % CI 0.146-0.806) and 0.086 (95 % CI 0.041-0.132), respectively. In conclusion, the brachial V E was significantly associated with the presence of coronary artery stenosis. The additional measurement of V E to the FRS improved the ability to identify patients with coronary artery stenosis among those with suspected stable CAD.