Arterial Wave Research Articles

Prediction of central Augmentation Index in healthy adults.

Central Augmentation Index (AIx) is a surrogate marker of large artery stiffness that may provide valuable insight to cardiovascular health. The aim of this study was to evaluate the relationship between AIx and components of physical fitness. One hundred eighty-five healthy men and women (aged 20-79 years) underwent non-invasive assessment of arterial wave reflection to determine AIx, which was corrected to a heart rate of 75 beats per minute (AI×75). Body composition was evaluated using dual energy X-ray absorptiometry (DXA) and aerobic capacity (VO<inf>2max</inf>) was derived from expired gas analysis during a symptom limited exercise test on a treadmill. A multiple linear regression revealed age and VO<inf>2max</inf> as significant predictors of AI×75 [AI×75=32.055 + (0.252×age) - (0.722×VO<inf>2max</inf>)]. Upon removal of VO<inf>2max</inf> from regression analysis, resting heart rate (RHR) and % body fat (BF%) were revealed to be significant predictors of AI×75: AI×75=-61.316 + (0.481×age) + (0.565×BF%) + (0.56×RHR). Our findings demonstrate that central Augmentation Index can be reliably predicted in healthy adults who undergo a maximal exercise or body composition assessment. These prediction equations may be applied in non-medical settings to assist in creating comprehensive health and fitness profiles for healthy clientele.

Arterial-myocardial coupling in primary AL amyloidosis. A validation study of vascular involvement

Abstract Background Primary AL amyloidosis is a rare yet lethal systemic disorder. Previously published own and others’ work indicated that vascular involvement in AL cardiac amyloidosis defined as low blood pressure or paradoxical vasodilation may independently affect survival. Mechanistic data will pave the way to validate the clinical role of vascular involvement in these patients. Purpose We sought to explore the presence of arterial-myocardial coupling in AL amyloidosis by investigating associations between markers of vascular and cardiac involvement. Methods We consecutively recruited n=152 newly diagnosed patients with AL amyloidosis that underwent thorough vascular examination including reactive vasodilation (flow mediated vasodilation, FMD and vasodilation in response to cold-pressor test) using high resolution ultrasonography. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (PWV) and aortic pressures and markers of arterial wave reflections were estimated using radial artery tonometry. In a subgroup of patients, transthoracic echocardiography (n=152) and cardiac magnetic resonance (CMR) (n=59) were performed. Results Vascular reactivity correlated with global longitudinal strain (GLS), left ventricle ejection fraction (LVEF)/GLS ratio and worse LV volumes. Vasodilation post-cold pressure test was correlated with LV mass. cSBP exhibited a negative correlation with markers of heart involvement, wall thickness markers, GLS, and CMR tissue characterization markers. A positive correlation between cSBP and LVEF, rotation and twist strain, myocardial work and contractility markers and late gadolinium enhancement (LGE). cDBP was associated with systolic function and contractility markers, with myocardial work indices and LGE. A negative relationship with GLS, LA strain, RV GLS and LA diameter and E/e’ was noted. In addition, T2 was negatively correlated with cDBP. SBP was correlated positively with LVEF, contractility markers, and LGE myocardium and negatively correlated with biomarkers of heart involvement, GLS, CMR structure and tissue characterization. DBP was positively correlated with LGE and myocardial work. A negative relation with NTproBNP, E/e’, RVSP, LA diameter and T2 mapping was noted. Time of wave reflections (Tr) was negatively correlated with rotation strain and positively correlated with circumferential strain, LA strain and LV structure. Ai@75 was positively correlated with myocardial work and contractility markers, and LGE. Ai@75 was negatively correlated with markers of heart involvement, LV structure, E/e’, worse GLS and adverse CMR tissue characterization. Conclusion Markers of peripheral vascular dysfunction were associated with cardiac structure and function acquired both with echocardiography and CMR in AL amyloidosis. This arterial-myocardial coupling supports the clinical role of peripheral vascular involvement in this disease and warrants further investigation.

Cardiovascular and vasomotor pulsations in the brain and periphery during awake and NREM sleep in a multimodal fMRI study.

The cerebrospinal fluid dynamics in the human brain are driven by physiological pulsations, including cardiovascular pulses and very low-frequency (< 0.1 Hz) vasomotor waves. Ultrafast functional magnetic resonance imaging (fMRI) facilitates the simultaneous measurement of these signals from venous and arterial compartments independently with both classical venous blood oxygenation level dependent (BOLD) and faster arterial spin-phase contrast. In this study, we compared the interaction of these two pulsations in awake and sleep using fMRI and peripheral fingertip photoplethysmography in both arterial and venous signals in 10 healthy subjects (5 female). Sleep increased the power of brain cardiovascular pulsations, decreased peripheral pulsation, and desynchronized them. However, vasomotor waves increase power and synchronicity in both brain and peripheral signals during sleep. Peculiarly, lag between brain and peripheral vasomotor signals reversed in sleep within the default mode network. Finally, sleep synchronized cerebral arterial vasomotor waves with venous BOLD waves within distinct parasagittal brain tissue. These changes in power and pulsation synchrony may reflect systemic sleep-related changes in vascular control between the periphery and brain vasculature, while the increased synchrony of arterial and venous compartments may reflect increased convection of regional neurofluids in parasagittal areas in sleep.

The novel and slowest arterial pressure waves: clinical implications in children with congenital heart disease following cardiovascular surgery.

Certain rhythmic arterial pressure waves in humans and animals have been noticed for over one century. We found the novel and slowest arterial pressure waves in children following surgical repair for CHD, and examined their characteristics and clinical implications. We enrolled 212 children with 22 types of CHD within postoperative 48 h. We monitored haemodynamics (blood pressure, cardiac cycle efficiency, dP/dTmax), cerebral (ScO2), and renal (SrO2) oxygen saturation every 6 s. Electroencephalogram was continuously monitored. Mean blood flow velocity (Vm) of the middle cerebral artery was measured at 24 h. We found the waves with a frequency of ∼ 90 s immediately following surgical repair in 46 patients in 12 types of CHD (21.7%), being most prevalent in patients with aortic arch abnormalities (Aorta Group, n = 24, 42.3%) or ventricular septal defect (Ventricular Septal Defect Group, n = 12, 23.5%). In Aorta and Ventricular Septal Defect Groups, the occurrence of the waves was associated with lower blood pressures, dP/dTmax, cardiac cycle efficiency, ScO2, SrO2, Vm, worse electroencephalogram background abnormalities, higher number of electroencephalogram sharp waves, and serum lactate (Ps <0.0001-0.07), and were accompanied with fluctuations of ScO2 and SrO2 in 80.6% and 69.6% of patients, respectively. The waves observed in children following cardiovascular surgery are the slowest ever reported, occurring most frequently in patients with aortic arch abnormalities or ventricular septal defect. While the occurrence of the waves was associated with statistically worse and fluctuated ScO2 and SrO2, worse systemic haemodynamics, and electroencephalogram abnormalities, at present these waves have no known clinical relevance.

Early elevations in arterial pressure: a contributor to rapid depressive symptom emergence in female Zucker rats with metabolic disease?

One of the growing challenges to public health and clinical outcomes is the emergence of cognitive impairments, particularly depressive symptom severity, because of chronic elevations in metabolic disease and cerebrovascular disease risk. To more clearly delineate these relationships and to assess the potential for sexual dimorphism, we used lean (LZR) and obese Zucker rats (OZR) of increasing age to determine relationships between internal carotid artery (ICA) hemodynamics, cerebral vasculopathies, and the emergence of depressive symptoms. Male OZR exhibited progressive elevations in perfusion pressure within the ICA, which were paralleled by endothelial dysfunction, increased cerebral arterial myogenic activation, and reduced cerebral cortex microvessel density. In contrast, female OZR exhibited a greater degree of ICA hypertension than male OZR but maintained normal endothelial function, myogenic activation, and microvessel density to an older age range than did males. Although both male and female OZR exhibited significant and progressive elevations in depressive symptom severity, these were significantly worse in females. Finally, plasma cortisol concentration was elevated higher and at a younger age in female OZR as compared with males, and this difference was maintained to final animal usage at ∼17 wk of age. These results suggest that an increased severity of blood pressure waves may penetrate the cerebral circulation more deeply in female OZR than in males, which may predispose the females to a more severe emergence of depressive symptoms with chronic metabolic disease, whereas males may be more predisposed to more direct cerebral vasculopathies (e.g., stroke, transient ischemic attack).NEW & NOTEWORTHY We provide novel insight that the superior maintenance of cerebrovascular endothelial function in female versus male rats with chronic metabolic disease buffers myogenic activation of cerebral resistance arteries/arterioles despite worsening hypertension. As hypertension development is earlier and more severe in females, potentially due to an elevated stress response, the blunted myogenic activation allows greater arterial pressure wave penetrance into the cerebral microcirculation and is associated with accelerated emergence/severity of depressive symptoms in obese female rats.

Early wave reflection of carotid artery is associated with 18F-FDG PET hypometabolism in Alzheimer's brain areas of cognitively normal adults.

Arterial stiffening likely plays a role in Alzheimer disease (AD) pathogenesis. The current study investigated whether inter-individual variations in arterial stiffness and pressure wave parameters were associated with 18F-FDG positron emission tomography (PET) metabolism in AD-associated brain areas throughout adulthood, independently of age and before the onset of any neuropsychological disorders. A prospective, large age-range population of 67 patients (17 young, 16 middle-aged, and 34 older adults; 37 women) underwent a: brain 18F-FDG PET, blood pressure recording, and carotid/femoral pulse wave-based measurements, including the time-to-peak of the reflected backward carotid pulse wave (bT), on the same day. Multivariable and quantitative voxel-to-voxel analyses (P-voxel < 0.005, corrected for cluster volumes) were conducted to assess associations between vascular parameters and 18F-FDG PET metabolism in AD-associated brain areas. In the multivariable analysis, only increased age and decreased bT were independently associated with the decline of metabolic activity in AD-associated brain areas (P < 0.001). In the voxel-to-voxel analysis with age as a covariate, bT was strongly associated with the metabolic activity of 40 clusters in AD-associated brain areas (clusters cumulative volume: 63 cm3; T score max: 5.7). In a large age-range population of adult patients, who are still unaffected by neuropsychological disorders, an early reflected arterial pressure wave, as evidenced by a decreased bT value, is strongly associated with hypometabolic activity of AD-associated brain areas, independently of age.

Attenuated Arterial Wave Reflection Associated With Fatigue In Youth Women’S Football Tournament: Impact Of Match-repetition

Attenuated Arterial Wave Reflection Associated With Fatigue In Youth Women’S Football Tournament: Impact Of Match-repetition

Detection of natural pulse waves (PWs) in 3D using high frame rate imaging for anisotropy characterization

IntroductionNumerous studies have shown that natural mechanical waves have the potential to assess the elastic properties of the myocardium. When the Aortic and Mitral valves close, a shear wave is produced, which provides insights into tissue stiffness. In addition, the Atrial Kick (AK) generates a wave similar to Pulse Waves (PWs) in arteries, providing another way to assess tissue stiffness. However, tissue anisotropy can also impact PW propagation, which is currently underexplored. This study aims to address this gap by investigating the impact of anisotropy on PW propagation in a phantom.MethodsTube phantoms were created using Polyvinyl Alcohol (PVA). Anisotropy was induced between two sets of two freeze-thaw cycles by stretching and twisting the material. The study first tests and validates the procedure of making helical anisotropic vessel phantoms using the shear wave imaging technique (by estimating the shear wave speed at different probe angles). Using plane wave ultrasound tomography synchronized with a peristaltic pump, 3D high frame rate imaging is performed and used to detect the 3D propagation pattern of PW for each manufactured vessel phantom. Finally, the study attempts to extract the anisotropic coefficient of the vessel using pulse wave propagation angle.ResultsThe Shear wave imaging results obtained for the isotropic vessel show very similar values for each probe angle. On the contrary, the results obtained for the axial anisotropy vessel show a region with a higher shear wave speed at about 0°, corresponding to the long axis of the vessel. Finally, the results obtained for the helical anisotropy depicted increasing shear wave velocity value from −20° to 20°. For the axial phantom, the wavefront of the pulse wave is perpendicular to the long axis of the vessel, while oriented for the helical anisotropic vessels phantom. The pulse wave propagation angle increased with the number of twists made during the vessel manufacturing.DiscussionThe results show that anisotropy can be induced in PVA vessel phantoms by stretching and twisting the material in freeze-thaw cycles. The findings also suggest that vessel anisotropy affects pulse wave propagation angles. Estimating the pulse wave propagation angle may be interesting in characterizing tissue anisotropy in organs where such waves are naturally present.

Validation of a New Ankle Brachial Index Measurement System Using Pulse Wave Velocity.

Peripheral artery disease (PAD) is a common circulatory disorder characterized by the accumulation of fats, cholesterol, and other substances in the arteries that restrict blood flow to the extremities, especially the legs. The ankle brachial index (ABI) is a highly reliable and valid non-invasive test for diagnosing PAD. However, the traditional method has limitations. These include the time required, the need for Doppler equipment, the training of clinical staff, and patient discomfort. PWV refers to the speed at which an arterial pressure wave propagates along the arteries, and this speed is conditioned by arterial elasticity and stiffness. To address these limitations, we have developed a system that uses electrocardiogram (ECG) and photoplethysmography (PPG) signals to calculate pulse wave velocity (PWV). We propose determining the ABI based on this calculation. Validation was performed on 22 diabetic patients, and the results demonstrate the accuracy of the system, maintaining a margin of ±0.1 compared with the traditional method. This confirms the correlation between PWV and ABI and positions this technique as a promising alternative to overcome some of the limitations of the conventional method.

Arterial stiffness and wave reflection responses to acute and chronic high intensity interval training in healthy older adults

Aging leads to large elastic artery stiffness which is associated with early return of wave reflection. These age-related alterations increase left ventricular afterload, predisposing older adults to cardiovascular disease. Endurance training is an effective strategy to reduce cardiovascular disease risk. We have developed a supervised home-based exercise intervention using high intensity interval training on an all-extremity non-weight-bearing ergometer (HIIT-ANE). This study aimed to test the following hypotheses in healthy older adults: 1) arterial stiffness and wave reflection would decrease in response to chronic HIIT-ANE, 2) arterial stiffness and wave reflection responses to acute HIIT-ANE would differ in the untrained compared to the trained states, and 3) arterial stiffness and aortic wave reflection responses to acute and chronic HIIT-ANE would be related. Twenty older adults (66±1 years, mean ± SE; 11 postmenopausal women and 9 men) participated in this study. Carotid-femoral pulse wave velocity (cfPWV) and augmentation index at heart rate 75 bpm (AIx@75)—indices of arterial stiffness and wave reflection, respectively—were assessed by SphygmoCor XCEL at baseline (T0), following 8 weeks of normal lifestyle (T1; control condition), and following 8 weeks of supervised home-based HIIT-ANE (T2). Acute cfPWV and AIx@75 responses to HIIT-ANE were assessed at pre-, end-of-, 1-hr post- and 24-hrs post-exercise, in the untrained and trained states. cfPWV increased after 8 weeks of normal lifestyle (T0 vs. T1: 7.9±0.3 vs. 8.2±0.3 m/s, P=0.03), but it decreased following 8 weeks of HIIT-ANE (T1 vs. T2: 8.2±0.3 vs. 7.7±0.3 m/s, P&lt;0.001). AIx@75 decreased after 8 weeks of HIIT-ANE compared to baseline and following 8 weeks of normal lifestyle (T0 vs. T2: 23.7±1.8 vs. 17.8±1.9 %, P&lt;0.001; T1 vs. T2: 24.9±2.2 vs. 17.8±1.9 %, P&lt;0.001). Acute cfPWV and AIx@75 responses to HIIT-ANE were similar in the untrained and trained states ( P for condition×time interaction; cfPWV: P=0.8; AIx@75: P=0.9). cfPWV and AIx@75 responses to chronic HIIT-ANE were not significantly related with acute responses to HIIT-ANE in the untrained (cfPWV: r=0.07, P=0.8; AIx@75: r=-0.32, P=0.2) and trained states (cfPWV: r=0.10, P=0.7; AIx@75: r=-0.32, P=0.2). In conclusion, we have demonstrated that supervised home-based HIIT-ANE has beneficial vascular effects in healthy older adults. We also showed that acute vascular responses to HIIT-ANE do not change from the untrained to trained state and are not predictive of chronic vascular responses to HIIT-ANE. This work was supported by the National Institute of Aging grant AG063143. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of Aging and Hypertension on Ambulatory Blood Pressure, Arterial Stiffness, and Wave Reflection in Mid-life Adults

Introduction: Age-associated increases in blood pressure are partly due to increased arterial stiffness and wave reflection. How these vascular changes during aging contribute to daily fluctuations in blood pressure and hypertension remain to be elucidated. Therefore, the purpose of this study is to compare ambulatory blood pressure, arterial stiffness, and wave reflection between young healthy adults, mid-life adults without hypertension, and mid-life adults with hypertension. Methods: Twenty-five young (age: 26 ± 4 yr and body mass index [BMI]: 23.9 ± 2.5 kg/m2) and 31 mid-life adults (age: 57 ± 4 yr and BMI: 25.4 ± 2.6 kg/m2), free of obesity and major clinical diseases and non-smokers, were included. Hypertension was defined by the current use of anti-hypertension medications or offce seated blood pressure (BP) ≥ 130/80 mmHg. Young adults with hypertension were excluded. Twenty-four-hour ambulatory BP monitoring (Oscar 2™, SunTech Medical®) and assessment of aortic arterial stiffness and wave reflection (SphygmoCor XCEL, AtCor Medical) were performed in all participants. Results: Daytime, nighttime, and 24-hr systolic BP was similar between young adults (YA) and mid-life adults without hypertension (MA; n=12; P&gt;0.9 vs. YA), while mid-life adults with hypertension (MAHTN; n=19) had higher offce, 24-hr, daytime, and nighttime systolic and diastolic BP compared to YA and MA (p&lt;0.01 vs. YA and MA). Compared to YA, MA had higher nighttime diastolic BP (P=0.02). Aortic arterial stiffness, measured by carotid-to-femoral pulse wave velocity, was the highest in MAHTN (p&lt;0.001 vs. YA and P=0&lt;0.01 vs. MA), followed by MA (p&lt;0.01 vs. YA) and YA. Aortic wave reflection, measured by augmentation index and reflection magnitude, was higher in MA and MAHTN compared to YA but was similar between MA and MAHTN (p&lt;0.001 for MA vs. YA; p&lt;0.001 for MAHTN vs. YA; and P&gt;0.9 for MA vs. MAHTN). Conclusions: Our findings indicate that 1) mid-life adults with hypertension had higher ambulatory BP and arterial stiffness than mid-life adults without hypertension and young adults; 2) despite normal offce blood pressure, mid-life adults without hypertension had higher nighttime diastolic BP and arterial stiffness than young adults; and 3) regardless of hypertension, mid-life adults had higher wave reflection than young adults. These findings suggest that 1) vascular aging may present prior to the diagnosis of hypertension based on offce BP; 2) arterial stiffness, rather than wave reflection, may contribute to the development of hypertension during aging; and 3) compared to offce BP, ambulatory BP may be a more sensitive marker of age-associated increases in blood pressure. NIAAA K99/R00 AA028537 to CLH. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of At-Risk Drinking on Ambulatory Blood Pressure in Young Adults

Introduction: At-risk drinking is associated with an increased risk of cardiovascular diseases (CVD) even in young adults. However, this association is mainly based on offce blood pressure (BP) measurement. Ambulatory BP monitoring captures diurnal variation in BP and is a more sensitive CVD predictor than offce BP. Therefore, the purpose of this study is to investigate the effects of at-risk drinking on ambulatory BP in young healthy adults with normal offce BP. Method: A total of 20 healthy men and women (21-35 years), non-smokers, were included in this cross-sectional study. All participants had an offce BP lower than 130/80 mmHg. Using the US Alcohol Use Disorders Identification Test (USAUDIT), at-risk drinkers were defined as those having a total USAUDIT score higher than 7 for men (6 for women). All participants underwent 24-hour ambulatory BP monitoring (Oscar 2™, SunTech Medical®). To investigate the vascular mechanisms underlying the effects of at-risk drinking on ambulatory blood pressure, aortic arterial stiffness and wave reflection were measured as pulse wave velocity (PWV) and augmentation index (AIx) by using SphygmoCor XCEL system (AtCor Medical). Results: No differences were found in age and BMI between at-risk drinkers (n=10) vs. low-risk drinkers (n=10; mean ± SD for age: 26.7 ± 3.7 vs. 26.6 ± 4.3 years, P&gt;0.99 and BMI: 24.5 ± 2.4 vs. 23.8 ± 2.9 kg/m2, P=0.6). At-risk drinkers had a higher total USAUDIT score (10.6 ± 2.7 vs. 1.4 ± 1.2, p&lt;0.001). While there was no difference between at-risk drinkers and low-risk drinkers in 24-hour, daytime, and nighttime systolic and diastolic BP (P≥0.5), at-risk drinkers had a higher blood pressure morning surge compared to low-risk drinkers (systolic: 34 ± 10 vs. 22 ± 6 mmHg, P=0.014 and diastolic: 29 ± 9 vs. 15 ± 4 mmHg, P=0.002). No significant difference was found in PWV (5.7 ± 0.6 Vs. 5.5 ± 0.7 m/sec, P=0.4) and AIx (8 ± 8 Vs. 15 ± 11, P=0.1). Conclusion: Our results indicate that despite similar offce BP, young adult at-risk drinkers had higher BP morning surge, an independent risk factor for cardiovascular events, than low-risk drinkers. These findings provide implications in using USAUDIT and out-of-offce BP measurements for cardiovascular disease risk assessment. This work was supported by NIAAA AA028537 to CLH. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Sex Differences in Central Hemodynamics of Patients with Untreated Obstructive Sleep Apnea

Patients with obstructive sleep apnea (OSA) have increased risk for cardiovascular diseases. Data from the Atherosclerosis Risk in the Communities and Sleep Heart Health Study suggest that OSA is more deleterious to females versus males, although mechanistic data are lacking. Estimates of central (aortic) blood pressure (BP) are superior in predicting future cardiovascular events than traditional brachial BP measurements. While patients with OSA have altered central hemodynamics (e.g., higher aortic pulse wave velocity; PWV), potential sex differences are unexplored. We tested the hypothesis that females with OSA (n=7, 50±3yrs, 35.1±1.9kg/m2, 22.2±7.6 events/hr) have worse central hemodynamics than males with OSA (n=9, 47±3yrs, 35.0±1.4kg/m2, 31.7±6.2 events/hr). Data collection consisted of an overnight sleep study (polysomnography) to identify the presence, and characterize the severity, of OSA via the apnea-hypopnea index (AHI). Then, duplicate measures of central (aortic) and peripheral (brachial) BP, as well as central artery stiffness (PWV) and wave reflection (AIx), were made in the morning after ≥15min of quiet, supine rest. Additional hemodynamic measurements were made if data differed by ≥2% (AIx) or ≥0.5m/s (PWV). Data that met these criteria were averaged and used for analysis. Comparisons were made using two-tailed, independent samples t-tests or nonparametric Mann-Whitney Rank Sum tests, as indicated. No differences were observed in age (p=0.44), body mass index (p=0.96), nor AHI (p=1.00) between sexes. Similarly, no sex differences were observed in brachial systolic (female vs. male: 129±7 vs. 134±8mmHg, p=0.83), diastolic (77±5 vs. 85±4mmHg, p=0.26), or mean BP (96±6 vs. 101±5mmHg, p=0.45). Similarly, central systolic (122±6 vs. 125±7mmHg, p=0.96), diastolic (78±5 vs. 86±4mmHg, p=0.25), and augmentation (21±2 vs. 15±2mmHg, p=0.07) BP did not differ between sexes. Resting heart rate was also comparable between groups (67±3 vs. 65±2bpm, p=0.64). However, AIx (AIx; 42±3 vs. 35±4%) and AIx normalized to a heart rate of 75bpm (42±3 vs. 30±3%) were higher in females with OSA relative to males with OSA (p&lt;0.05 for both). Interestingly, the forward (30±3 vs. 28±2mmHg, p=0.63) and reflected (20±2 vs. 18±2mmHg, p=0.44) pulse heights, as well as PWV (7.3±0.6 vs. 7.4±0.6m/s, p=0.85), were similar between groups. Our data indicate that despite a trend towards higher BP in males with OSA (~5mmHg) that may be clinically, though not statistically different, females with OSA have a higher AIx. As AIx is positively associated with left ventricular hypertrophy, these data also suggest that altered central (aortic) hemodynamics may contribute to the sex differences in cardiovascular risk with OSA. This work was supported by the National Institutes of Health T32-HL007111 and U54AG044170 (JMB), HL065176 (PS and VKS), and HL134885 (VKS). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Evaluating Vascular Depth-Dependent Changes in Multi-Wavelength PPG Signals Due to Contact Force.

Photoplethysmography (PPG) is a non-invasive method used for cardiovascular monitoring, with multi-wavelength PPG (MW-PPG) enhancing its efficacy by using multiple wavelengths for improved assessment. This study explores how contact force (CF) variations impact MW-PPG signals. Data from 11 healthy subjects are analyzed to investigate the still understudied specific effects of CF on PPG signals. The obtained dataset includes simultaneous recording of five PPG wavelengths (470, 525, 590, 631, and 940 nm), CF, skin temperature, and the tonometric measurement derived from CF. The evolution of raw signals and the PPG DC and AC components are analyzed in relation to the increasing and decreasing faces of the CF. Findings reveal individual variability in signal responses related to skin and vasculature properties and demonstrate hysteresis and wavelength-dependent responses to CF changes. Notably, all wavelengths except 631 nm showed that the DC component of PPG signals correlates with CF trends, suggesting the potential use of this component as an indirect CF indicator. However, further validation is needed for practical application. The study underscores the importance of biomechanical properties at the measurement site and inter-individual variability and proposes the arterial pressure wave as a key factor in PPG signal formation.

Characterization of arterial wave reflection phenomena during a long-term swine experiment of sepsis and resuscitation

Characterization of arterial wave reflection phenomena during a long-term swine experiment of sepsis and resuscitation

Detection of medial vascular calcification in chronic kidney disease based on pulse wave analysis in the frequency domain

Medial vascular calcification (mVC), particularly prevalent in patients with chronic kidney disease (CKD), is a pathological deposition of minerals in the medial layer of the vessel wall and is associated with an increased risk of cardiovascular disease. Currently, there is no cost–effective and non-invasive procedure of mVC assessment in routine clinical practice. We explored whether in–depth analysis of non-invasively recorded peripheral pulse waves can serve as an effective mVC biomarker.The study included 97 CKD patients with histological assessment of mVC in the epigastric artery and pulse wave measurements in the brachial artery. Pulse waves were analysed in the frequency domain to obtain features, which, together with traditional mVC risk factors (i.e., age, sex, and body mass index), were used to build generalized linear models for mVC prediction. The classifiers with the best scores in terms of balanced accuracy were combined in an ensemble establishing the final model.The final, ensembled model, assessed using a leave-one-out cross-validation process, achieved a balanced accuracy equal to 0.87, an accuracy of 0.93, an AUC ROC of 0.91, and an F-score of 0.96. Apart from the features associated with pulse waves, the selected variables included age, sex, body mass index, heart rate and diastolic blood pressure.Analysis of non-invasively recorded peripheral pulse waveforms combined with traditional risk factors, can help to detect mVC in CKD patients and thus, potentially introduce risk-lowering therapeutic strategies at earlier disease stages in the future.

Abstract P516: Vascular Risk Assessment in Youth With Familial Hypercholesterolemia and Combined Dyslipidemia of Obesity

Introduction: Pulse wave analysis (PWA) assesses vascular health by estimating arterial wave reflections noninvasively and is associated with cardiovascular (CV) events in adults in recent studies. However, data in youth are lacking. Individuals with CV risk factors such as familial hypercholesterolemia (FH) or combined dyslipidemia of obesity (CDO) have increased risk of adult-onset CV disease. Using PWA may help improve risk stratification of young patients with adverse CV risk factors and enhance disease management. Hypothesis: We hypothesized that youth with adverse CV risk factors would have differences in arterial wave reflections compared to controls. Methods: Demographic, anthropometric, and fasting lipid values were obtained in 124 patients aged 9-25 years in a study comparing vascular health among normolipidemic controls (N=47), FH (N=45), and CDO (N=32). PWA was obtained using the SphygmoCor XCEL device, and wave separation analyses were performed from brachial artery assessments. Group differences were assessed by chi-square, ANOVA, or Kruskal-Wallis test as appropriate by variable type and distribution normality. Results: There were significant differences between groups in adiposity (CDO with higher BMI, p&lt;0.001) and lipid levels with a more adverse lipid profile (higher TC, LDL, &amp; TG; lower HDL) for the FH and CDO groups versus controls (all p&lt;0.001). The CDO group had higher forward pulse wave amplitude (Pf) versus the control and FH groups (p=0.0002, Figure) and higher backward pulse wave amplitude (Pb) versus controls (p=0.0013). Differences in Pf or Pb between FH and controls did not reach significance. Conclusions: Adolescents and young adults with CDO have altered forward and backward wave reflections compared to normolipidemic controls. It is possible that PWA differences between the FH and control groups may become significant over time. These novel parameters suggest early vascular changes in youth with CDO and may help improve risk stratification in youth with adverse CV risk factors.

Comparative evaluation of stroke volume variation measured by pulse wave transit time and arterial pressure wave.

Several monitors have been developed that measure stroke volume (SV) in a beat-to-beat manner. Accordingly, Stroke volume variation (SVV) induced by positive pressure ventilation is widely used to predict fluid responsiveness. The purpose of this study was to compare the ability of two different methods to predict fluid responsiveness using SVV, stroke volume variation by esCCO (esSVV) and stroke volume variation by FloTrac/VigileoTM (flSVV). esSVV, flSVV, and stroke volume index (SVI) by both monitoring devices of 37 adult patients who underwent laparotomy surgery, were measured. Receiver operating characteristic (ROC) analysis was performed. The area under the ROC curve (AUC) of esSVV was significantly higher than that of flSVV (p= 0.030). esSVV and flSVV showed cutoff values of 6.1% and 10% respectively, to predict an increase of more than 10% in SVI after fluid challenge. The Youden index for esSVV was higher than flSVV, even with a cutoff value between 6% and 8%. Since esSVV and flSVV showed significant differences in AUC and cutoff values, the two systems were not comparable in predicting fluid responsiveness. Furthermore, it seems that SVV needs to be personalized to accurately predict fluid responsiveness for each patient.

Anesthesia for Craniotomy Tumor Removal Patient with Morbid Obesity

Purpose: Obesity is one of the greatest health challenges in the western world. Obesity is defined as a body mass index (BMI) &gt;30 kg/m2, with BMI &gt;35 and &gt;55 kg/m2 considered ‘morbidly’ obese and ‘super morbidly’ obese, respectively. The aim of this study was to examine anesthetic management for craniotomy tumor removal in patients with morbid obesity. Design/methodology/data analysis: This research uses a qualitative descriptive research method with a case study approach of a 39 year old female patient with a body weight of 110 kg, height 160 cm, and body mass index (BMI) 42.9 kg/m2, Mallampati score 2, thyromental distance &gt; 3 fingers hospitalized for removal of meningioma. Data collection techniques in this research used literature study, observation and laboratory tests. The data that has been collected is then analyzed descriptively. Findings: The results of the study showed that in the operating room, the patient was positioned in a neutral position 300 head up and Ramp. Preoxygenation with 100% O2 was performed via a face mask. Anesthesia was maintained with continuous intravenous propofol 25-50 μg/kg/min, intravenous rocuronium 40 mg/h, and volatile anesthesia using sevoflurane 0.5-1%vol with oxygen: air at a fraction of 50%. Monitoring during surgery includes evaluation of systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, oxygen saturation, ECG waves, EtCO2, and urine output. The operation lasted 4 hours in the supine position. Post-surgery patients are then treated in the Intensive Care Unit (ICU) for one day before being transferred to the ward and finally to a regular room. He received treatment for 5 days before being discharged. Problems faced during anesthesia in obese patients are airway management, ventilation, position, drug dosage, presence of comorbidities and post-operative care for recovery from anesthesia and surgery. Originality/value: While addressing common challenges encountered during anesthesia in obese patients, this research takes a step further by proposing innovative solutions. The study acknowledges the complexities of airway management, ventilation, positioning, drug dosage, comorbidities, and post-operative care. However, it introduces novel considerations or techniques to mitigate these challenges, possibly involving emerging technologies or interdisciplinary collaboration for enhanced patient outcomes. Practical implications: The practical implications of this research advocate for a nuanced and individualized approach to anesthetic management in morbidly obese patients undergoing craniotomy tumor removal, fostering improved patient care and safety.

BOLD cardiorespiratory pulsatility in the brain: from noise to signal of interest.

Functional magnetic resonance imaging (fMRI) based on the Blood Oxygen Level Dependent (BOLD) contrast has been extensively used to map brain activity and connectivity in health and disease. Standard fMRI preprocessing includes different steps to remove confounds unrelated to neuronal activity. First, this narrative review explores how signal fluctuations due to cardiac and respiratory activity, usually considered as "physiological noise" and regressed out from fMRI time series. However, these signal components bear useful information about some mechanisms of brain functioning (e.g., glymphatic clearance) or cerebrovascular compliance in response to arterial pressure waves. Aging and chronic diseases can cause stiffening of the aorta and other main arteries, with a reduced dampening effect resulting in greater transmission of pressure impulses to the brain. Importantly, the continuous hammering of cardiac pulsations can produce local alterations of the mechanical properties of the small cerebral vessels, with a progressive deterioration that ultimately affects neuronal functionality. Second, the review emphasizes how fMRI can study the brain patterns most affected by cardiac pulsations in health and disease with high spatiotemporal resolution, offering the opportunity to identify much more specific risk markers than systemic factors based on measurements of the vascular compliance of large arteries or other global risk factors. In this regard, modern fast fMRI acquisition techniques allow a better characterization of these pulsatile signal components due to reduced aliasing effects, turning what has been traditionally considered as noise in a signal of interest that can be used to develop novel non-invasive biomarkers in different clinical contexts.