Peripheral Arterial Tonometry Research Articles

Mindfulness-based Stress Reduction and Endothelial Function in Chronic Kidney Disease

Introduction: Chronic Kidney Disease (CKD) is associated with increased cardiovascular disease risk in part due to endothelial dysfunction. Studies have suggested that mindfulness-based stress reduction (MBSR) may have beneficial physiologic effects on cardiovascular disease risk; however, the potential beneficial effects of MBSR on endothelial function in CKD are unknown. We tested the hypothesis that MBSR improves endothelial function in patients with CKD. Methods: Participants with CKD (Stages III-IV) were enrolled and randomized to 8 weeks of MBSR versus the Health Enhancement Program (HEP), a structurally parallel control intervention to MBSR. Each intervention consisted of daily homework and 2.5hr weekly classes of mindfulness meditation (for MBSR) and health education (for HEP). Each intervention also included a day-long retreat. Endothelial function was quantified as brachial artery reactive hyperemia index (RHI) using peripheral artery tonometry (EndoPAT). RHI and offce blood pressure were obtained at baseline and at the end of the intervention. Intervention groups were also stratified into subgroups based on normal (RHI ≥2.10) and abnormal (RHI <2.10) baseline values for secondary analyses. Results: Data were obtained from 37 participants with CKD who were enrolled and randomized to MBSR (N=21) versus HEP (N=16). There were no differences in baseline characteristics, hemodynamics or RHI between groups. There were no significant differences in baseline versus end of study RHI within (HEP p=0.76; MBSR p=0.57) and between intervention groups (p=0.36). There was no difference in change in RHI after MBSR between the normal and abnormal RHI subgroups. Conclusions: MBSR did not have significant effects on endothelial function measured as RHI among individuals with CKD. Supported by NIH Grants R33AT010457 and R01HL135183. 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.

Prediction of in-hospital complications in takotsubo syndrome: prospective cohort study

BACKGROUND: Until recently, takotsubo syndrome (TS) was considered a fairly benign disease in both early and late periods. However, in recent years, in-hospital complications in the acute period of TS are common and can be life-threatening.
 AIM: Based on clinical and laboratory-instrumental data, this study aimed to build models for predicting the risk of developing in-hospital complications in patients with TS during the acute period.
 MATERIALS AND METHODS: This prospective cohort study included 60 patients with TS, with an average age of 65.5±13.4 years. In the acute period (7–14 days), standard clinical and laboratory examination, peripheral arterial tonometry using the «EndoPAT 2000» apparatus, and psychological testing using validated questionnaires (hospital anxiety and depression scale and Beck depression scale) were performed.
 RESULTS: The integrated model for predicting the risk of acute heart failure (AHF) development (pulmonary edema and cardiogenic shock) identified admission LVEF as the leading prognostic parameter. With LVEF ≤40.5%, the probability of AHF in patients with TS in the acute period was 62.5%, and in patients with TS and QTc interval 487 ms, the risk reached 100%. The sensitivity and specificity of the developed model were 72.7% and 97.4%, respectively. The integrated model for predicting the development of cardiovascular complications (CVCs) revealed that the number of leukocytes in the peripheral blood was the leading risk factor for adverse events in patients with TS in the acute period. With a leukocyte count 11.1×109/L, the risk of CVCs in patients with TS increased to 89.9%, and if the erythrocyte count was 4.69×1012/L or ≤4.29×1012/L, it could reach 100%. The sensitivity and specificity of the resulting model were 92.6 and 97.0%, respectively.
 CONCLUSION: The models proposed in this study for predicting the likelihood of developing severe AHF and the overall risk of CVCs in the acute period of TS are personalized and easy to use, allowing for the selection of optimized treatment techniques.

Endothelial function in patients with chronic myeloid leukemia treated with tyrosine kinase inhibitors is not related to cardiovascular risk assessed by the Systematic Coronary Risk Estimation 2 algorithm.

Tyrosine kinase inhibitors (TKIs) revolutionized treatment of chronic myeloid leukemia (CML), but are endowed with negative effects on endothelial function. We aimed to characterize endothelial function in patients with CML treated with various TKIs. A total of 48 patients diagnosed with chronic‑phase CML treated with TKIs, such as imatinib, bosutinib, nilotinib, ponatinib, and asciminib were included. Endothelial function was assessed in the brachial artery and microcirculation based on flow‑mediated dilation (FMD), reactive hyperemia peripheral arterial tonometry (RH‑PAT) and flow‑mediated skin fluorescence (FMSF). Reactive hyperemia index, FMD, reactive hyperemia response (RHR), normoxia oscillatory index, and hyperemic response index did not differentiate between the group of patients with low / moderate risk in the Systematic Coronary Risk Estimation 2 (SCORE2), SCORE2‑Older Persons (SCORE2‑OP), and those with high / very high risk scores. Among the patients with low / intermediate risk based on the SCORE2 algorithm, some had lower (below the first quartile) values of the endothelial parameters, reflecting impaired endothelial function, as compared with the high / very high risk patient population. Lower values of the endothelial function parameters were associated with overall long‑term treatment with TKIs or ponatinib. Importantly, endothelial function assessed by FMSF (RHR) negatively correlated with total duration of TKI treatment, also after adjustment for age. Endothelial function in CML patients treated with TKIs was not related to cardiovascular risk based on SCORE2/SCORE2‑OP algorithms but correlated with CML‑specific factors, including duration of TKI treatment. FMSF‑based assessment of skin microcirculation was a sensitive method for detecting the vascular effects of TKIs.

Lower glomerular filtration rate after mild stroke induces cognitive impairment by causing endothelial dysfunction

The incidence of post stroke cognitive impairment (PSCI) is high in patients with mild stroke (MIS), and the risk factors and mechanism are uncertain. Increased cystatin C (CysC) levels after stroke may reflect lower glomerular filtration rate (GFR) and renal impairment. Previous studies have suggested endothelial dysfunction (ED) is closely related to renal impairment and cognitive impairment, respectively. We aimed to observe whether lower GFR estimated by CysC after MIS leaded to a high incidence of PSCI, and the role of ED in this process. 256 patients were enrolled in this prospective observational study. Renal function was assessed using GFR estimated by serum CysC. Endothelial function was evaluated by reactive hyperemia index (RHI) which calculated automatically by peripheral arterial tonometry (PAT). The cognitive function at baseline and 3 months was evaluated by MoCA score, and MoCA score ≤ 26 indicates the presence of PSCI. Spearman correlation analysis and linear regression were conducted to explore the factors affecting ED. Univariate and multivariate analysis was used to identify the independent risk factors of PSCI. The receiver operating characteristic (ROC) curve was applied to explore the optimal cutoff value of the independent risk factors levels for predicting PSCI. A total of 141 patients (55.1%) suffered from ED. Multiple linear regression analysis showed that there was a strong linear correlation between eGFRcys and RHI (p < 0.001). At the three-month follow-up, a total of 150 (58.6%) patients had been diagnosed with PSCI. Multivariate logistic regression analysis showed that RHI was an independent factor affecting the occurrence of PSCI (p < 0.05). ROC curve showed that the area under the curve was 0.724, and the optimal cut-off value of RHI was 1.655, with the sensitivity and specificity for PSCI were 72.7% and 73.6%, respectively. The lower eGFRcys level after MIS was significantly associated with ED, and ED may mediate the higher incidence of PSCI at 3 months after MIS.

The Effect of Surgical Therapy for Obstructive Sleep Apnea on Blood Pressure and Peripheral Arterial Tonometry.

To determine the effect of upper airway surgery on cardiovascular function in patients with obstructive sleep apnea (OSA). A prospective, self-controlled study from 2018 to 2023. Two academic medical centers. Seventy-four patients underwent surgery for OSA, including: tonsillectomy, adenoidectomy, epiglottidectomy, modified uvulopalatopharyngoplasty, maxillary expansion, and maxillomandibular advancement. Twenty-four-hour ambulatory blood pressure (BP), peripheral arterial tonometry (PAT)-based home sleep study, and sleep-related patient-reported outcomes (PROs) were captured preoperatively and at 6 months postoperatively. Paired T-tests evaluated changes in outcomes after surgery. Forty-one patients successfully completed preoperative and postoperative assessments. Patients were generally middle-aged (43.8 ± 12.5 years), obese (BMI 33.0 ± 5.8 kg/m2), male (68%), White (71%), and had severe OSA (apnea-hypopnea index [AHI] 33.9 ± 29.5 events/h). The 4% oxygen desaturation index (ODI) decreased from 30.7 ± 27.1 to 12.2 ± 13.6 events/h(P < .01) after surgery. There was no significant difference in 24-hBP following surgery, though clinically meaningful reductions in nocturnal systolic (-1.95 [-5.34, 1.45] mmHg) and nocturnal diastolic (-2.30 [-5.11, 0.52] mmHg) blood pressure were observed. Stratified analysis showed patients undergoing skeletal surgery (n = 17) demonstrated larger average reductions compared to those undergoing soft tissue surgery in nocturnal systolic (-4.12 [-7.72, -0.51] vs-0.10 [-5.78, 5.58] mmHg) and nocturnal diastolic (-3.94 [-7.90, 0.01] vs-0.90 [-5.11, 3.31] mmHg) pressures. No meaningful changes were observed in PAT Autonomic Index (PAI) measurements. Surgical therapy for OSA did not demonstrate statistically significant improvements in 24-hBP. However, clinically meaningful reductions in nocturnal BP were observed, particularly in skeletal surgery patients, supporting the need for larger studies of cardiovascular outcomes following OSA surgery.

Long-term night-to-night variability of sleep-disordered breathing using a radar-based home sleep apnea test: a prospective cohort study.

Night-to-night variability of sleep-disordered breathing (SDB) limits the diagnostic accuracy of a single measurement. Multiple recordings using a reliable, affordable method could reduce the uncertainty and avoid misdiagnosis, which could be possible with radar-based home sleep apnea testing (HSAT). We recruited consecutive patients with suspected SDB and performed contactless radar-based HSAT with automated scoring (Sleepiz One) over ten nights. During the first night, patients were simultaneously measured with peripheral-arterial tonometry. Twenty-four of the 28 included patients could achieve a minimum of four measurements. The failure rate was 16% (201 of 238 measurements). The apnea-hypopnea index (AHI) and oxygen desaturation index were consistently lower with radar-based HSAT compared to peripheral arterial tonometry. The variability of the AHI was considerable, with a standard error of measurement of 5.2/h (95%CI 4.6-5.7/h) and a minimal detectable difference of 14.4/h (95%CI 12.7-15.9/h). Alcohol consumption partially accounted for the variability, with an AHI increase of 1.7/h (95%CI 0.6-2.8/h) for each standard drink. Based on a single measurement, 17% of patients were misdiagnosed, and 32% were misclassified for SDB severity. After five measurements, the mean AHI of the measured nights stabilized with no evidence of substantial changes with additional measurements. Night-to-night variability is considerable and stable over ten nights. HSAT using radar-based methods over multiple nights is feasible and well tolerated by patients. It could offer lower costs and allow for multiple-night testing to increase accuracy. However, validation and reducing the failure rate are necessary for implementation in the clinical routine. "Recording of Multiple Nights Using a New Contactless Device (Sleepiz One Connect) in Obstructive Sleep Apnea", ClinicalTrials.gov, NCT05134402.

Association between Inflammation, Glycocalyx Biomarkers, and Endothelial Function in Children with Hypercholesterolemia

Introduction: Hypercholesterolemia is a risk factor for premature arteriosclerosis. Inflammation and oxidative stress are thought to contribute to endothelial dysfunction preceding vasculopathy. We investigated the association between inflammation, glycocalyx biomarkers, endothelial function, and vascular parameters in children with hypercholesterolemia. Methods: In 22 patients (LDL-cholesterol >130 mg/dL; median age [IQR]: 13 [2.3] years) and 22 controls (13 [2.5] years), tumor necrosis factor-alpha (TNF-α), oxidized cholesterol (oxLDL), and glycocalyx biomarkers (Syndecan-1, Hyaluronan) were measured using immunoassays. Endothelial function was assessed by peripheral arterial tonometry, sublingual glycocalyx and microcirculation by videomicroscopy and carotid intima-media thickness by ultrasound. Results: OxLDL was significantly higher in patients (78.9 [38.2] vs. 50.3 [16.6] U/L, p = 0.002), whereas all other experimental parameters were comparable between groups. Multivariate analysis revealed a significant association of Syndecan-1 with TNF-α (β = 0.75, p p = 0.030). The interaction term combining TNF-α and hypercholesterolemia showed a significant effect (p = 0.034). Sex was an independent predictor of endothelial function. Conclusion: The combined effect of hypercholesterolemia and inflammation on glycocalyx perturbation and the impact of sex in the premature development of arteriosclerosis deserve further evaluation. Therapeutic approaches tackling low-grade systemic inflammation may offer potential to prevent or delay progression of cardiovascular disease and cardiovascular complications.

Acute Effects of Coffee Consumption on Blood Pressure and Endothelial Function in Individuals with Hypertension on Antihypertensive Drug Treatment: A Randomized Crossover Trial.

Coffee is a complex brew that contains several bioactive compounds and some of them can influence blood pressure (BP) and endothelial function (EF), such as caffeine and chlorogenic acids (CGAs). This study aimed to evaluate the acute effects of coffee on BP and EF in individuals with hypertension on drug treatment who were habitual coffee consumers. This randomized crossover trial assigned 16 adults with hypertension to receive three test beverages one week apart: caffeinated coffee (CC; 135mg caffeine, 61mg CGAs), decaffeinated coffee (DC; 5mg caffeine, 68mg CGAs), and water. BP was continuously evaluated from 15min before to 90min after test beverages by digital photoplethysmography. Reactive hyperemia index (RHI) assessed by peripheral arterial tonometry evaluated EF before and at 90min after test beverages. At the same time points, microvascular reactivity was assessed by laser speckle contrast imaging. Repeated-measures-ANOVA evaluated the effect of time, the effect of beverage, and the interaction between time and beverage (treatment effect). Although the intake of CC produced a significant increase in BP and a significant decrease in RHI, these changes were also observed after the intake of DC and were not significantly different from the modifications observed after the consumption of DC and water. Microvascular reactivity did not present significant changes after the 3 beverages. CC in comparison with DC and water neither promoted an acute increase in BP nor produced an improvement or deleterious effect on EF in individuals with hypertension on drug treatment who were coffee consumers.

Higher prevalence of coronary microvascular dysfunction in asymptomatic individuals with high levels of lipoprotein(a) with and without heterozygous familial hypercholesterolaemia

Background and aimsMicrovascular dysfunction underlies many cardiovascular disease conditions; little is known regarding its presence in individuals with high levels of lipoprotein(a) [Lp(a)]. The aim of the present study was to determine the frequency of microvascular dysfunction among such subjects with and without concomitant familial hypercholesterolemia (FH). MethodsFour groups of asymptomatic individuals aged 30–59 years, without manifest cardiovascular disease, were recruited (n = 30 per group): controls with Lp(a) < 30 nmol/L, mutation-confirmed FH with Lp(a) < 30 nmol/L, or >125 nmol/L, and individuals with isolated Lp(a) > 125 nmol/L. Participants underwent evaluation of myocardial microvascular function by measuring coronary flow reserve (CFR) using transthoracic Doppler echocardiography, and of peripheral microvascular endothelial function by peripheral arterial tonometry. ResultsThe groups were balanced in age, sex, and body mass index. Each of the three dyslipoproteinaemic groups had a greater proportion of individuals with impaired coronary flow reserve, 30%, compared to 6.7% of controls (p = 0.014). The median CFR levels did not differ significantly between the four groups, however. Cholesterol-lowering treatment time was longer in the individuals with normal than in those with impaired CFR in the FH + Lp(a) > 125 group (p = 0.023), but not in the group with FH + Lp(a) < 30 (p = 0.468). There was no difference in peripheral endothelial function between the groups. ConclusionsCoronary microvascular dysfunction is more prevalent in asymptomatic individuals with isolated Lp(a) elevation and in heterozygous FH both with and without high Lp(a) compared to healthy controls. Cholesterol-lowering treatment could potentially prevent the development of microvascular dysfunction.

Assessment of oropharyngeal respiratory volume and sleep apnoea scores using peripheral arterial tonometry may improve diagnosis and treatment planning of combined dysgnathia therapy approaches.

Increased daytime sleepiness is a frequently reported symptom in patients with pronounced dysgnathia. This study investigated possible correlations using home peripheral arterial tonometry (PAT) and oropharyngeal airway volume determination in patients with dysgnathia and daytime sleepiness. Twenty patients (13 male, median age 27.6 ± 6.8 years) with abnormal sleep history and 10 skeletal neutral configured controls (6 male, median age 29.5 ± 4.2 years) with normal sleep history were examined. Patients and controls were evaluated for apnoea-hypopnoea index (AHI), respiratory disturbance index (RDI), oxygen desaturation index (ODI), snoring volume (dB), total sleep time (TST) and REM-percentage (REM). Airway volumetry was measured via CBCT. Individual user experience for PAT was assessed using the User Experience Questionnaire (UEQ). Patients had significantly higher respiratory scores than controls. AHI increased 4.6-fold (p = .006), RDI 2.5-fold (p = .008) and ODI 6.4-fold (p < .001). Oropharyngeal volumes showed a 30% decrease (p = .003). dB, TST and REM showed no significant differences. AHI (r = -.51; p = .005), ODI (r = -.60; p < .001) and RDI (r = -.45; p = .016) correlated negatively with pharyngeal volume. Wits appraisal correlated negatively with oropharyngeal volume (r = -.47; p = .010) and positively with AHI (r = .41; p = .03) and ODI (r = .49; p = .007). dB and TST (r = -.49; p = .008) and REM and RDI (r = -.43; p = .02) correlated negatively. UEQ-KPI (2.17 ± 0.24) confirmed excellent usability of PAT. Patients with mandibular retrognathia and abnormal sleep history showed significantly higher respiratory indices and smaller oropharyngeal volumes than neutrally configured controls. The dygnathia severity directly influenced the risk of obstructive sleep apnoea.

Exaggerated Peripheral and Systemic Vasoconstriction During Trauma Recall in Posttraumatic Stress Disorder: A Co-Twin Control Study

BackgroundIndividuals with posttraumatic stress disorder (PTSD) face an increased risk of cardiovascular disease, but the mechanisms linking PTSD to cardiovascular disease remain incompletely understood. We used a co-twin control study design to test the hypothesis that individuals with PTSD exhibit augmented peripheral and systemic vasoconstriction during a personalized trauma recall task. MethodsIn 179 older male twins from the Vietnam Era Twin Registry, lifetime history of PTSD and current (last month) PTSD symptoms were assessed. Participants listened to neutral and personalized trauma scripts while peripheral vascular tone (Peripheral Arterial Tone ratio) and systemic vascular tone (e.g., total vascular conductance) were measured. Linear mixed-effect models were used to assess the within-pair relationship between PTSD and vascular tone indices. ResultsThe mean age of participants was 68 years, and 19% had a history of PTSD. For the Peripheral Arterial Tone ratio analysis, 32 twins were discordant for a history of PTSD, and 46 were discordant for current PTSD symptoms. Compared with their brothers without PTSD, during trauma recall, participants with a history of PTSD had greater increases in peripheral (β = −1.01, 95% CI [−1.72, −0.30]) and systemic (total vascular conductance: β = −1.12, 95% CI [−1.97, −0.27]) vasoconstriction after adjusting for cardiovascular risk factors. Associations persisted after adjusting for antidepressant medication use and heart rate and blood pressure during the tasks. Analysis of current PTSD symptom severity showed consistent results. ConclusionsPTSD is associated with exaggerated peripheral and systemic vasoconstrictor responses to traumatic stress reminders, which may contribute to elevated risk of cardiovascular disease.

Cardiovascular Risk Markers in Adults With Adrenal Incidentaloma and Mild Autonomous Cortisol Secretion.

Many adrenal adenomas exhibit mild autonomous cortisol secretion (MACS). Although MACS is associated with increased cardiovascular mortality, the underlying mechanisms are not fully defined. To investigate mechanisms that may link MACS and cardiovascular mortality in adults with adrenal adenoma. Cross-sectional study. Twenty adults with adrenal adenoma and MACS and 20 controls with nonfunctioning adrenal adenoma. Reactive hyperemia index (RHI) was measured by peripheral artery tonometry and 24-hour ambulatory blood pressure monitoring (24h AMBP) was performed. Indices of insulin secretion and sensitivity were estimated by measuring glucose and insulin fasting and following a mixed meal. The primary outcome was the difference in RHI between participants with MACS vs nonfunctioning adrenal adenoma. The average cortisol after 1-mg dexamethasone and urinary free cortisol were higher in patients with MACS. There was no significant difference in fasting RHI (2.0 [interquartile range (IQR) 1.6-2.4] vs 2.0 [IQR 1.7-2.2, P = .72), but postprandial RHI was higher in patients with MACS (2.2 [1.8-2.7] vs 1.8 [1.5-2.2], P = .04). 24-hour ambulatory blood pressure monitoring and Matsuda index were not significantly different in the groups. Fasting glucose and glucose area under the curve after the mixed meal were higher and insulinogenic index was lower in participants with MACS. Adults with adrenal adenoma and MACS do not have fasting endothelial dysfunction and postprandial endothelial function may be better. These patients have fasting and postprandial hyperglycemia with lower insulin secretion, which may underlie the association between MACS and increased cardiovascular mortality.

Myocardial microvascular dysfunction in asymptomatic patients with hereditary dyslipidemia

Abstract Introduction Microvascular dysfunction underlies the pathophysiology of many cardiovascular disease (CVD) conditions and is strongly associated with future cardiovascular events. Hereditary forms of dyslipidaemia such as familial hypercholesterolemia (FH) and high levels of lipoprotein(a) [Lp(a)] are associated with premature atherosclerotic CVD but the degree of microvascular dysfunction in asymptomatic individuals is not fully explored. Purpose To evaluate the presence of microvascular dysfunction in asymptomatic individuals with the hereditary dyslipidaemias FH and high Lp(a). Methods Asymptomatic individuals without manifest CVD were recruited to four groups with 30 subjects in each; 1) controls with Lp(a)&amp;lt;30 nmol/L, 2) FH+Lp(a)&amp;lt;30 nmol/L, 3) FH+Lp(a)&amp;gt;125 nmol/L, and 4) isolated Lp(a)&amp;gt;125 nmol/L without FH. FH diagnoses were confirmed by genetic analysis. Transthoracic doppler echocardiography was used to record coronary flow in the distal part of the left anterior descending artery at rest and during hyperaemia induced by intravenous infusion of adenosine. Coronary flow reserve (CFR) was calculated by dividing hyperaemic to basal flow. Peripheral microvascular endothelial function was determined by recording reactive hyperaemia index (RHI) by peripheral arterial tonometry in the index fingers of both hands. CFR and RHI were considered impaired if values were &amp;lt;2.5 and &amp;lt;1.67, respectively. Results The four groups were balanced in age (mean 42.6±8.4 years), sex (50% females), BMI (mean 25.0±4.7 kg/m2), and smoking status (5.0% current smokers). Low-density lipoprotein cholesterol was also similar across the four groups (mean 2.8±1.1 mmol/L) with the two FH groups being on cholesterol lowering treatment while the other two were pharmacologically naïve. The three groups with hereditary dyslipidaemia had a higher proportion of subjects with impaired CFR, 30.0% in each group compared to 6.6% in controls (p=0.014) (Figure 1A). The FH+Lp(a)&amp;lt;30 nmol/L and FH+Lp(a)&amp;gt;125 nmol/L groups had received cholesterol lowering treatment for a median (inter quartile range, IQR) of 4.0 (8.0) and 11.0 (11.0) years respectively (p&amp;lt;0.001). In the FH+Lp(a)&amp;gt;125 nmol/L group individuals with normal CFR had received significantly longer treatment (p=0.006) but not in the FH+Lp(a)&amp;lt;30 nmol/L group (p=0.568) (Figure 1B). There were no major differences in median CFR (p=0.550) (Figure 2A) or median RHI (p=0.341) (Figure 2B) levels between the four groups. Conclusion Asymptomatic individuals with the hereditary dyslipidaemias FH and/or high Lp(a) have a higher degree of coronary microvascular dysfunction compared to healthy controls. For individuals with combined traits FH and high Lp(a), the total treatment years of cholesterol lowering is associated with preserved coronary microvascular function suggesting CFR as a potential useful non-invasive tool for cardiovascular risk-stratification in patients with hereditary dyslipidaemias.Figure 1Figure 2

Abstract 11582: The Fingertip Artery is Better Than the Brachial Artery in Evaluating Vascular Endothelial Function for Coronary Artery Disease in Diabetic Patients

Introduction: Several studies demonstrated that endothelial function is impaired in diabetic patients, but no study evaluated vascular parameters in diabetic patients trough a combined analysis of macro and micro-endothelial function. In addition, the difference in vascular parameters between diabetes patients with coronary artery disease (CAD) and without CAD remains unknown. We assessed whether CAD is related to macro or micro vascular endothelial function in diabetic patients. Hypothesis: We measured vascular function in 219 diabetic patients (age 68±10 years), including 147 patients with CAD (CAD group) and 72 patients without CAD (control group). Flow mediated vasodilatation (FMD)indicating macro-endothelial function in the brachial artery was measured by ultrasound using a semi-automatic device: UNEXEF18G (UNEX Co. Nagoya, Japan). Reactive hyperemia index (RHI) indicating micro-endothelial function in the fingertip artery was measured by peripheral arterial tonometry (EndoPAT 2000). Vascular function tests were measured on the same day. Results: RHI was significantly impaired in CAD group (RHI: 2.0±0.7 vs.1.7±0.5 P=0.012), however FMD had no deference in the two groups. Logistic regression analysis revealed that RHI (odds ratio: 0.44, 95% confidence interval: 0.21-0.94) was an independent predictor for CAD in diabetic patients. Conclusions: RHI, an acknowledged marker of micro-endothelial function was a more sensitive method than FMD in evaluating the risk assessment of CAD in diabetic patients. more peripheral vascular endothelial function was associated with CAD in diabetic patients.

Abstract 18949: Bariatric Surgery is Associated With Improved Coronary Microvascular Function and Cardiorespiratory Fitness in Patients With Ischemia and Non-Obstructive Coronary Arteries (INOCA)

Introduction - Severe obesity is associated with cardiometabolic disease and coronary microvascular dysfunction, as reflected by impaired coronary flow reserve (CFR). Bariatric surgery promotes sustained weight loss and lower incidence of diabetic microvascular complications, but its effect on the coronary microcirculation is unclear. In this ongoing pilot study, we aimed to investigate the impact of bariatric surgery on CFR, endothelial function, and cardiorespiratory fitness in patients with severe obesity and INOCA. Methods - Consecutive patients (N=19) with severe obesity (BMI≥35 kg/m 2 ), exertional dyspnea and planned bariatric surgery were enrolled. Patients underwent cardiac stress positron emission tomography (PET), peripheral arterial tonometry (PAT), echocardiogram and cardiopulmonary exercise testing (CPET) at baseline and after a median of 6.2 months post-surgery (N=9 completed to date). CFR was quantified as stress/rest myocardial blood flow (MBF) from PET. Reactive hyperemia index (RHI), a marker of endothelial function, was calculated as the ratio between PAT signal post and pre-occlusion in the corresponding arm. Results - Median age was 50 (Q1-Q3 42-54) years and 63% were female. At baseline, median BMI was 43 (40-54), LVEF was 0.62, and %LV visual ischemia was 0. Higher BMI inversely correlated with CFR (r= -0.53, p=0.02). As compared to baseline, patients post-surgery (78% sleeve gastrectomy, 22% gastric bypass) had significantly decreased BMI (45.2 vs. 34.3, p=0.008) and improved stress MBF [1.8 (1.3-2.2) vs. 2.4 (1.8-2.8), p&lt;0.02], CFR [2.3 (1.9-2.6) vs. 3.1 (2.4-3.6), p&lt;0.02] and peripheral endothelial function [RHI 1.5 (1.4-1.8) vs. 2.4 (1.8-2.8) vs. p=0.04]. These changes were accompanied on CPET by significantly higher exercise workload [112 (84.2-146) vs. 124.5 (90.5-149) W, p=0.046] and relative peak VO 2 [12.5 (11.9-14) vs. 15.2 (12.6-17) mL/kg/min, p=0.028]. Higher stress MBF directly correlated with relative peak VO 2 (r=0.53, p=0.04). Conclusion - In this pilot clinical study, bariatric surgery was associated with significant improvements in coronary microvascular function, peripheral endothelial function, and cardiorespiratory fitness in symptomatic patients with severe obesity after six months.

Abstract 13947: Racial Differences in Peripheral Microvasculature's Association With Mild Cognitive Impairment

Introduction: Cardiovascular disease (CVD) and Alzheimer’s Dementia (AD) share numerous risk factors, with vascular dysfunction a common underlying mechanism. Individuals with mild cognitive impairment (MCI) have a high likelihood of developing AD in their lifetime. The link between microvascular dysfunction (MVD) and AD has yet to be fully established. Hypothesis: We examined the contribution of MVD to MCI with the hypothesis that Black Americans, who have a higher prevalence of MVD, will have higher rates of MCI. Methods: Participants &gt;50 years with MCI or with normal cognition (NC) were enrolled for neuropsychological and microvascular function testing using peripheral arterial tonometry. Microvascular function was measured as the reactive hyperemia index (RHI) and calculated as the ratio of the post- to pre-occlusion pulse volume in the fingertip (EndoPAT). Multivariate analyses, adjusting for demographic and CVD risk factors associated with MCI, evaluated the relationship between RHI and MCI in Black and White participants. Causal mediation analysis, using the Monte Carlo approach, was performed to investigate whether the effect of RHI on MCI was mediated through plausible mediators, including risk factors. Results: Of 152 participants (NC=104, MCI=48), 41.4% were Black and 33.6% male. Participants with MCI were more likely to be Black (58.3% vs 33.7%%, p=0.007) and have lower RHI (1.93 vs 2.27, p=0.004) compared to NC. RHI was an independent predictor of MCI with a 96% adjusted greater odds of MCI per unit reduction in RHI. Black race remained an independent predictor of MCI (OR 2.90, 95% CI [1.16, 7.56]). RHI was lower in Black compared to White participants (1.86 vs 2.37, p&lt;0.001). There was no heterogeneity in the impact of RHI on MCI. In a casual mediation analysis, MCI was mediated via RHI more in Black than in White participants (proportion mediated 24.2% vs 18.4%, p=0.034) after multivariate adjustment. Conclusions: Peripheral MVD, measured as RHI, was independently associated with MCI. Furthermore, Black participants exhibited lower RHI levels, a higher prevalence of MCI, and potentially mediated MCI through RHI to a greater extent compared to their White counterparts.

A new approach to streamline obstructive sleep apnea therapy access using peripheral arterial tone-based home sleep test devices

Obstructive sleep apnea (OSA) is a prevalent condition that negatively impacts cardiovascular, metabolic and mental health. A high proportion of individuals with OSA remain undiagnosed and incur significant healthcare costs. The gold standard OSA diagnostic is in-lab polysomnography, but this is costly and time-consuming. Home sleep apnea tests (HSATs), including cardiorespiratory polygraphy and peripheral artery tonometry technology, provide an alternative. Advances in HSAT technology include non-invasive, easy-to-use medical devices that could allow unobtrusive, accessible, multi-night, cost-effective diagnosis and management of sleep-disordered breathing. One type of these devices is based on determination of peripheral arterial tone, and use photoplethysmography signals from the finger (oxygen saturation, pulse wave amplitude and pulse rate). The devices contain algorithms that use these data to generate the traditional metrics required by the American Academy of Sleep Medicine. They can be used to record sleep parameters over multiple nights at home, and can also provide information on total sleep time (TST) and sleep stages (including time spent in rapid eye movement sleep). The combination of objective measures (apnea-hypopnea index, oxygen desaturation index, respiratory disturbance index, TST) and subjective measures (symptoms and other patient-reported outcome measures) could facilitate the development of a personalized therapeutic plan for OSA patients. It is anticipated that the streamlined digital pathway facilitated by new peripheral artery tone-based technology could contribute to reducing the underdiagnosis of OSA, accelerating access to appropriate treatment, and the optimization of OSA therapy.

Assessment of the Value of the PAT as the First Step in the Triage Process in a Pediatric Emergency Room

Background: This study aimed to examine the correlation between the pediatric assessment triangle (PAT) and the rate of hospitalization among pediatric patients. Patients presenting to the pediatric emergency department were categorized based on PAT criteria during the study period, and retrospective data analysis was conducted. The primary outcome measure was the percentage of patients with PAT findings who required hospital admission; however, the secondary outcome measure focused on the association between PAT findings and admission to the pediatric intensive care unit (PICU) and the comparison between hospitalization rates with disrupted PAT versus blood testing as the initial diagnostic step. Methods: In this study, 622 patients were enrolled, and among them, 246 patients (39.5%) had normal findings in the peripheral arterial tonometry (PAT) test. The researchers conducted both univariate and multivariate analyses to investigate the relationship between PAT results and hospitalization. They also examined the association between hospitalization and abnormal findings in more than one component of PAT, presentation at the emergency department, performance of blood tests showing abnormalities in more than one component, and appearance while accounting for potential confounding factors. By adjusting for these confounders, the researchers aimed to assess the independent impact of PAT on hospitalization risk and identify any significant associations. Results: The study revealed a strong association between impaired PAT findings and hospitalization, both in univariate and multivariate analyses. Abnormal findings in &gt;1 component of PAT, appearance in the emergency department, and abnormal findings in &gt;1 component of blood tests were the most significant factors related to hospitalization, even after adjusting for confounders. Conversely, normal PAT findings showed no association with either the primary or secondary outcomes. Furthermore, hospitalization rates differed significantly between patients with impaired PAT and those with normal PAT. Conclusions: Impaired PAT findings, when utilized by pediatricians, are associated with increased hospitalization rates, even during the peak of the coronavirus disease 2019 (COVID-19) pandemic. Moreover, it is crucial to emphasize physician training in utilizing PAT effectively as the initial step in evaluating pediatric patients in the emergency room, potentially reducing the need for additional costly testing and enabling physicians to make more confident decisions.

O026 Concordance between a home sleep apnoea test based on peripheral artery tonometry and laboratory polysomnography

Abstract Introduction Limited channel home sleep apnoea test (HSAT) devices are an emerging alternative to laboratory-based PSG. Despite increasingly commercially availability, there is limited external validation of their diagnostic performance. We recently independently validated the Night Owl Mini HSAT (NOM) against in-lab PSG and demonstrated a satisfactory level of agreement (LOA) of 63.8% overall. However, lower rates of agreement were observed for severe OSA. We speculated that signal artefact may have contributed to reduced concordance. Methods Data was drawn from our previously published prospective cohort of 100 participants undergoing PSG for suspected OSA, simultaneously fitted with the NOM. PSG and NOM studies were re-processed, manually remarking artefact. LOA was recalculated comparing only temporally aligned data segments for which both devices provided intact signals, this allowed direct comparison of pulse oximetry data and software algorithms that generated the ODI3%. Two new datasets were generated for PSG and NOM for which combined artefact was deleted (COM-PSG, COM-NOM). Results To date, datasets from 12 participants have been assessed. The mean difference in ODI3% between PSG and NOM was 5.25/hr (95% limits of agreement -0.73 – 11.23), while the mean difference in ODI3% between COM-PSG and COM-NOM was 2.53/hr (95% limits of agreement -1.77 – 6.83). In our previous study, the overall mean difference in ODI3% was –0.21/hr (95% limits of agreement -18.1 – 17.7). Conclusion Preliminary results may indicate signal artefact contributes to reduced level of agreement between PSG and NOM.

Association of Vitamin D and Endothelial Function in a Subsample of the Participants in the Longitudinal Study of Adult Health (ELSA-BRASIL)

The Longitudinal Study of Adult Health (ELSA-BRASIL) is a multicentric and multidisciplinary cohort study aimed at investigating the incidence and risk factors of chronic diseases. Vitamin D deficiency has been associated with several comorbidities. In this context, the need to assess the impact of vitamin D on endothelial dysfunction in a large-scale study is justified. Thus, in this study, serum levels of vitamin D were determined by HPLC in 509 participants of the ELSA-BRASIL, and its association with endothelial function parameters by Peripheral Arterial Tonometry (BPA and PATratio). Reduced levels of vitamin D were shown to be associated with indicative measures of worse endothelial function. In the logistic regression model, the variables male sex, white color, increase in age, BMI, triglycerides, and vitamin D&lt;30ng/mL were also indicative of worse endothelial function. In summary, vitamin D has presented an association with endothelial function, which may indicate a protective action of vitamin D to the vascular endothelium.