Transcatheter aortic valve implantation and its impact on endothelial function in patients with aortic stenosis.

Vascular function is impaired in patients with aortic valve stenosis (AS). The impact of transcatheter aortic valve implantation (TAVI) on endothelial function is inconclusive so far. Therefore, we sought to assess the short-term influence of TAVI on endothelial dysfunction in patients with AS. We recruited 47 patients (76.6 % male, 80.04 years old) with AS scheduled for TAVI. Endothelial function was assessed by fingertip reactive hyperemia peripheral arterial tonometry (RH-PAT). Measurements were conducted one day before and three days after TAVI. Patients were grouped according to RH-PAT change after TAVI. Overall, RH-PAT measurements did not significantly improve after TAVI (Reactive Hyperemia Index: 1.5 vs 1.6, p = 0.883; logarithm of the Reactive Hyperemia Index: 0.44 vs. 0.49, p = 0.523). Interestingly, patients with no RH-PAT improvement after TAVI displayed a more severe AS and had lower blood pressure after TAVI. This might be due to a more disturbed blood flow in patients with a smaller aortic valve area and higher peak aortic valve velocity. The relationship between AS severity, endothelial dysfunction and TAVI has to be investigated in future research that apply longitudinal study designs.

OSA diagnosis goes wearable: are the latest devices ready to shine?

STUDY OBJECTIVES: From 2019-2023, the United States Food and Drug Administration has cleared 9 novel obstructive sleep apnea-detecting wearables for home sleep apnea testing, with many now commercially available for sleep clinicians to integrate into their clinical practices. To help clinicians comprehend these devices and their functionalities, we meticulously reviewed their operating mechanisms, sensors, algorithms, data output, and related performance evaluation literature. METHODS: We collected information from PubMed, United States Food and Drug Administration clearance documents, ClinicalTrials.gov, and web sources, with direct industry input whenever feasible. RESULTS: In this "device-centered" review, we broadly categorized these wearables into 2 main groups: those that primarily harness photoplethysmography data and those that do not. The former include the peripheral arterial tonometry-based devices. The latter was further broken down into 2 key subgroups: acoustic-based and respiratory effort-based devices. We provided a performance evaluation literature review and objectively compared device-derived metrics and specifications pertinent to sleep clinicians. Detailed demographics of study populations, exclusion criteria, and pivotal statistical analyses of the key validation studies are summarized. CONCLUSIONS: In the foreseeable future, these novel obstructive sleep apnea-detecting wearables may emerge as primary diagnostic tools for patients at risk for moderate-to-severe obstructive sleep apnea without significant comorbidities. While more devices are anticipated to join this category, there remains a critical need for cross-device comparison studies as well as independent performance evaluation and outcome research in diverse populations. Now is the moment for sleep clinicians to immerse themselves in understanding these emerging tools to ensure our patient-centered care is improved through the appropriate implementation and utilization of these novel sleep technologies. CITATION: Chiang AA, Jerkins E, Holfinger S, et al. OSA diagnosis goes wearable: are the latest devices ready to shine? J Clin Sleep Med. 2024;20(11):1823-1838.

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

OBJECTIVE: To determine the effect of upper airway surgery on cardiovascular function in patients with obstructive sleep apnea (OSA). STUDY DESIGN: A prospective, self-controlled study from 2018 to 2023. SETTING: Two academic medical centers. METHODS: 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. RESULTS: 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-h BP 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. CONCLUSION: Surgical therapy for OSA did not demonstrate statistically significant improvements in 24-h BP. 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.

STUDY OBJECTIVES: Night-to-night variability of sleep-disordered breathing 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). METHODS: We recruited consecutive patients with suspected sleep-disordered breathing and performed contactless radar-based HSAT with automated scoring (Sleepiz One; Sleepiz AG, Zurich, Switzerland) over 10 nights. During the first night, patients were simultaneously measured with peripheral arterial tonometry. RESULTS: Twenty-four of the 28 included patients could achieve a minimum of 4 measurements. The failure rate was 16% (37 of 238 measurements). The apnea-hypopnea index (AHI) and oxygen desaturation index were consistently lower with radar-based HSAT compared with peripheral arterial tonometry. The variability of the AHI was considerable, with a standard error of measurement of 5.2 events/h (95% confidence interval [CI]: 4.6-5.7 events/h) and a minimal detectable difference of 14.4 events/h (95% CI: 12.7-15.9 events/h). Alcohol consumption partially accounted for the variability, with an AHI increase of 1.7 events/h (95% CI: 0.6-2.8 events/h) for each standard drink. Based on a single measurement, 17% of patients were misdiagnosed and 32% were misclassified for sleep-disordered breathing severity. After 5 measurements, the mean AHI of the measured nights stabilized with no evidence of substantial changes with additional measurements. CONCLUSIONS: Night-to-night variability is considerable and stable over 10 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. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Recording of Multiple Nights Using a New Contactless Device (Sleepiz One Connect) in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/study/NCT05134402; Identifier: NCT05134402. CITATION: Tschopp S, Borner U, Caversaccio M, Tschopp K. Long-term night-to-night variability of sleep-disordered breathing using a radar-based home sleep apnea test: a prospective cohort study. J Clin Sleep Med. 2024;20(7):1079-1086.

Pre-procedural Stratification by the Endothelial Function in Patients with Heart Failure Undergoing Atrial Fibrillation Ablation.

BACKGROUND: Endothelial dysfunction (ED), a well-established risk marker of cardiovascular events, is associated with heart failure (HF) and atrial fibrillation (AF). Its relationship with cardiovascular events in patients with HF undergoing AF ablation remains unclear. We aimed to elucidate the association between ED and the outcomes after AF ablation in patients with HF. METHODS: This prospective cohort study included patients with HF who underwent an endothelial function assessment using the peripheral vascular reactive hyperemia index (RHI) before first-time AF ablation. We defined AF recurrence according to the following types: the conventional form (AF≥30 seconds) and persistent form (requiring cardioversion). An RHI<2.1 indicated ED. Those with and without ED were compared in terms of the 3-year incidence of AF recurrence and cardiovascular events after AF ablation. RESULTS: Among 421 patients with HF (69 ± 9 years and 38% females), 343 (81.5%) had ED. Although the incidence of the conventional form of AF recurrence was similar between the groups, that of the persistent form was significantly higher in the ED group (25.7% vs. 15.3%, log-rank P = 0.028). The ED group also had a significantly higher rate of cardiovascular events (14.8% vs. 3.6%, log-rank P = 0.028). Pre-procedural ED was identified as an independent predictor of a persistent form of AF recurrence (adjusted hazard ratio [HR] 2.31, 95% confidence interval [CI] 1.05-5.07, P = 0.037) and that of cardiovascular events (adjusted HR 4.21, 95% CI 1.02-17.5, P = 0.048), respectively. CONCLUSIONS: The endothelial function assessment enabled the risk stratification of clinically problematic outcomes after AF ablation in patients with HF.

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

BACKGROUND: Increased daytime sleepiness is a frequently reported symptom in patients with pronounced dysgnathia. OBJECTIVES: This study investigated possible correlations using home peripheral arterial tonometry (PAT) and oropharyngeal airway volume determination in patients with dysgnathia and daytime sleepiness. METHODS: 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). RESULTS: 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. CONCLUSION: 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.

Microvascular Endothelial Function Assessed Using Peripheral Arterial Tonometry in Adolescents with Repaired Congenital Heart Disease.

Atherosclerosis can develop in adult patients with congenital heart disease (CHD) and should be given attention. Endothelial function is well known as a predictor of the development of atherosclerosis but has not been well investigated in patients with repaired CHD. This study aimed to clarify the endothelial function and its relationship with clinical backgrounds and parameters in adolescents with various types of repaired CHDs. Endothelial function was evaluated using peripheral arterial tonometry (PAT). The reactive hyperemia index (RHI) was evaluated and compared between adolescents with repaired CHD and those in the control group. The relationship between the clinical background and parameters was also investigated in patients with repaired CHD. Forty-eight patients with repaired CHD (age 14.0 ± 3.3 years) and 114 healthy volunteers were included in this study. Patients with repaired CHD comprised 16 with repaired non-cyanotic CHD, 14 with repaired tetralogy of Fallot, and 18 who underwent the Fontan procedure. RHI in the repaired CHD group was significantly lower than in the control group. There was no significant correlation between the RHI and blood biochemical markers, such as uric acid, creatine, and brain natriuretic peptide levels. The RHI was significantly higher in patients taking angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) than in those not taking them. Endothelial function was impaired in adolescents with repaired CHD compared to that in the control group. Microvascular endothelial dysfunction developed even in adolescents with simple non-cyanotic CHD.

Belun Ring (Belun Sleep System BLS-100): Deep learning-facilitated wearable enables obstructive sleep apnea detection, apnea severity categorization, and sleep stage classification in patients suspected of obstructive sleep apnea.

GOAL AND AIMS: Our objective was to evaluate the performance of Belun Ring with second-generation deep learning algorithms in obstructive sleep apnea (OSA) detection, OSA severity categorization, and sleep stage classification. FOCUS TECHNOLOGY: Belun Ring with second-generation deep learning algorithms REFERENCE TECHNOLOGY: In-lab polysomnography (PSG) SAMPLE: Eighty-four subjects (M: F = 1:1) referred for an overnight sleep study were eligible. Of these, 26% had PSG-AHI<5; 24% had PSG-AHI 5-15; 23% had PSG-AHI 15-30; 27% had PSG-AHI ≥ 30. DESIGN: Rigorous performance evaluation by comparing Belun Ring to concurrent in-lab PSG using the 4% rule. CORE ANALYTICS: Pearson's correlation coefficient, Student's paired t-test, diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, Cohen's kappa coefficient (kappa), Bland-Altman plots with bias and limits of agreement, receiver operating characteristics curves with area under the curve, and confusion matrix. CORE OUTCOMES: The accuracy, sensitivity, specificity, and kappa in categorizing AHI ≥ 5 were 0.85, 0.92, 0.64, and 0.58, respectively. The accuracy, sensitivity, specificity, and Kappa in categorizing AHI ≥ 15 were 0.89, 0.91, 0.88, and 0.79, respectively. The accuracy, sensitivity, specificity, and Kappa in categorizing AHI ≥ 30 were 0.91, 0.83, 0.93, and 0.76, respectively. BSP2 also achieved an accuracy of 0.88 in detecting wake, 0.82 in detecting NREM, and 0.90 in detecting REM sleep. CORE CONCLUSION: Belun Ring with second-generation algorithms detected OSA with good accuracy and demonstrated a moderate-to-substantial agreement in categorizing OSA severity and classifying sleep stages.

Validation of a single-use and reusable home sleep apnea test based on peripheral arterial tonometry compared to laboratory polysomnography for the diagnosis of obstructive sleep apnea.

STUDY OBJECTIVES: The objective of this study was to independently validate a disposable and a reusable home sleep apnea test (HSAT) recording on peripheral arterial tonometry, compared to laboratory polysomnography (PSG), for the diagnosis of obstructive sleep apnea (OSA). METHODS: 115 participants undergoing PSG for suspected OSA were recruited and fitted with the two study devices (NightOwl, Ectosense, Belgium). After exclusions were applied and device failures were removed, data from 100 participants were analyzed. HSAT-derived apnea-hypopnea index (AHI), OSA severity category, total sleep time, and oxygen desaturation index 3% were compared to PSG. RESULTS: Both study devices demonstrated satisfactory levels of agreement with minimal mean bias for determination of AHI and oxygen desaturation index 3% (disposable: AHI mean bias 2.04 events/h [95% limits of agreement -20.9 to 25.0], oxygen desaturation index 3% mean bias -0.21/h [-18.1 to 17.7]; reusable: AHI mean bias 2.91 events/h [-16.9 to 22.7], oxygen desaturation index 3% mean bias 0.77/h [-15.7 to 17.3]). Level of agreement diminished at higher AHI levels although misclassification for severe OSA occurred infrequently. Total sleep time level of agreement for the reusable HSAT was also satisfactory with minimal mean bias (4.18 minutes, -125.1 to 112.4), but the disposable HSAT was impacted by studies with high signal rejection (23.7 minutes, -132.7 to 180.1). Categorization of OSA severity demonstrated moderate agreement with laboratory PSG, with a kappa of 0.52 and 0.57 for the disposable and reusable HSATs respectively. CONCLUSIONS: The two HSAT devices were comparable and performed well compared to laboratory PSG for the diagnosis of OSA. CLINICAL TRIAL REGISTRATION: Registry: Australian New Zealand Clinical Trials Registry; Identifier: ANZCTR12621000444886. CITATION: Lyne CJ, Hamilton GS, Turton ARE, et al. Validation of a single-use and reusable home sleep apnea test based on peripheral arterial tonometry compared to laboratory polysomnography for the diagnosis of obstructive sleep apnea. J Clin Sleep Med. 2023;19(8):1429-1435.

The vascular function effects of adding exenatide or meal insulin to basal insulin therapy in early type 2 diabetes.

OBJECTIVE: Basal insulin glargine has a neutral effect on cardiovascular risk in type 2 diabetes (T2DM). In practice, basal insulin is often paired with a glucagon-like peptide-1 receptor agonist (GLP1-RA) or meal insulin; however, the cardiovascular implications of these combinations have not been fully elucidated. In this context, we sought to evaluate the vascular function effects of adding the GLP1-RA exenatide or meal insulin lispro to basal glargine therapy in early T2DM. METHODS: In this 20-week trial, adults with T2DM of < 7-years duration were randomized to 8-weeks treatment with (i) insulin glargine (Glar), (ii) glargine + thrice-daily lispro (Glar/Lispro), or (iii) glargine + twice-daily exenatide (Glar/Exenatide), followed by 12-weeks washout. At baseline, 8-weeks, and washout, fasting endothelial function was assessed with reactive hyperemia index (RHI) measurement by peripheral arterial tonometry. RESULTS: At baseline, there were no differences in blood pressure (BP), heart rate (HR) or RHI between participants randomized to Glar (n = 24), Glar/Lispro (n = 24), and Glar/Exenatide (n = 25). At 8-weeks, Glar/Exenatide decreased systolic BP (mean - 8.1 mmHg [95%CI - 13.9 to - 2.4], p = 0.008) and diastolic BP (mean - 5.1 mmHg [- 9.0 to - 1.3], p = 0.012) compared to baseline, with no significant changes in HR or RHI. Notably, baseline-adjusted RHI (mean ± SE) did not differ between the groups at 8-weeks (Glar 2.07 ± 0.10; Glar/Lispro 2.00 ± 0.10; Glar/Exenatide 1.81 ± 0.10; p = 0.19), nor did baseline-adjusted BP or HR. There were no differences between the groups in baseline-adjusted RHI, BP or HR after 12-weeks washout. CONCLUSION: Adding either exenatide or lispro to basal insulin therapy does not appear to affect fasting endothelial function in early T2DM. TRIAL REGISTRATION: ClinicalTrials.Gov NCT02194595.

Central Sleep Apnea Detection by Means of Finger Photoplethysmography.

Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA) are two types of Sleep Apnea (SA) with different etiologies and treatment options. Home sleep apnea testing based on photoplethysmography-derived peripheral arterial tonometry (PAT HSAT) has become the most widely deployed outpatient SA diagnostic method. Being able to differentiate between CSA and OSA based solely on photoplethysmography-data would further increase PAT HSAT's clinical utility. The present work proposes a method to detect CSA using finger photoplethysmography (PPG) data and evaluates the proposed method against simultaneous in-lab polysomnography (PSG). METHODS: For 266 patients with a suspicion of SA, concurrent in-lab PSG and PPG data were acquired. The respiratory information embedded in the PPG data was extracted and used to train an ensemble of trees classifiers that predicts the central or obstructive nature of each respiratory event. The classifier performance was evaluated using patient-wise leave-one-out cross-validation where an expert analysis of the PSG served as ground truth. A second, independent analysis of the PSG was also evaluated against the ground truth to allow benchmarking of the PPG-based method. RESULTS: The method achieved a sensitivity of 81%, a specificity of 99%, a positive predictive value of 90%, and a negative predictive value of 98% at the central apnea-hypopnea index cutoff of 10 events per hour of sleep. CONCLUSION AND SIGNIFICANCE: The present study aimed to evaluate a method to detect CSA in SA patients using only PPG data which could be used to flag CSA which in turn may aid in more optimal therapy decision making.

Evaluating an under-mattress sleep monitor compared to a peripheral arterial tonometry home sleep apnea test device in the diagnosis of obstructive sleep apnea.

STUDY OBJECTIVES: To evaluate whether or not the apnea-hypopnea index (AHI) from a peripheral arterial tonometry (PAT) home sleep apnea test (HSAT) is equivalent to the AHI provided by the mean of one, three, or seven nights from the Withings Sleep Analyzer (WSA) under-mattress device. METHODS: We prospectively enrolled patients with suspected OSA in whom a PAT-HSAT was ordered. Eligible patients used the WSA for seven to nine nights. PAT data were scored using the device's intrinsic machine learning algorithms to arrive at the AHI using both 3% and 4% desaturation criteria for hypopnea estimations (PAT3%-AHI and PAT4%-AHI, respectively). These were then compared with the WSA-estimated AHI (WSA-AHI). RESULTS: Of 61 patients enrolled, 35 completed the study with valid PAT and WSA data. Of the 35 completers 16 (46%) had at least moderately severe OSA (PAT3%-AHI ≥ 15). The seven-night mean WSA-AHI was 2.13 (95%CI = - 0.88, 5.14) less than the PAT3%-AHI, but 5.64 (95%CI = 2.54, 8.73) greater than the PAT4%-AHI. The accuracy and area under the receiver operating curve (AUC) using the PAT3%-AHI ≥ 15 were 77% and 0.87 and for PAT4%-AHI ≥ 15 were 77% and 0.85, respectively. The one-, three-, or seven-night WSA-AHI were not equivalent to either the 3% or 4% PAT-AHI (equivalency threshold of ± 2.5 using the two one-sided t-test method). CONCLUSIONS: The WSA derives estimates of the AHI unobtrusively over many nights, which may prove to be a valuable clinical tool. However, the WSA-AHI over- or underestimates the PAT-AHI in clinical use, and the appropriate use of the WSA in clinical practice will require further evaluation. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04778748.

Endothelial function testing before conditioning therapy is useful for predicting transplant-related complications after allogeneic hematopoietic cell transplantation.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is a useful tool for the treatment of hematologic malignancies. However, transplantation-related complications are the main cause of non-relapse mortality. Previous reports suggest that endothelial damage is related to early complications after HSCT. Non-invasive reactive hyperemia peripheral arterial tonometry (RH-PAT) was performed to evaluate endothelial function as a predictive marker for these complications. METHODS: The reactive hyperemia index (RHI) obtained from RH-PAT was evaluated before the conditioning regimen. The relationship between the RHI and the appearance of engraftment syndrome, thrombotic microangiopathy, and acute graft-versus-host disease (aGVHD) was assessed. Receiver operating characteristic curve analysis showed that an RHI value of 1.58 was the optimal cut-off for predicting transplantation-related complications. RESULTS: In total, 49 patients (22 acute myelogenous leukemia, 7 acute lymphocytic leukemia, 6 myelodysplastic syndrome, 6 adult T-cell leukemia, 6 non-Hodgkin lymphoma, and 2 others) were enrolled; 34 had a normal RHI (≥ 1.59), and 15 had an abnormally low RHI (≤ 1.58). Thrombotic microangiopathy (20.2% vs 0.0%, P = 0.025) and aGVHD (80.0% vs 41.2%, P = 0.015) were significantly more frequent in patients with a low RHI. CONCLUSION: Endothelial dysfunction assessed by RH-PAT before HSCT was able to predict transplantation-related complications.

Clinical impact of manual scoring of peripheral arterial tonometry in patients with sleep apnea.

PURPOSE: The objective was to analyze the clinical implications of manual scoring of sleep studies using peripheral arterial tonometry (PAT) and to compare the manual and automated scoring algorithms. METHODS: Patients with suspected sleep-disordered breathing underwent sleep studies using PAT. The recordings were analyzed using a validated automated computer-based scoring and a novel manual scoring algorithm. The two methods were compared regarding sleep stages and respiratory events. RESULTS: Recordings of 130 patients were compared. The sleep stages and time were not significantly different between the scoring methods. PAT-derived apnea-hypopnea index (pAHI) was on average 8.4 events/h lower in the manually scored data (27.5±17.4/h vs.19.1±15.2/h, p<0.001). The OSA severity classification decreased in 66 (51%) of 130 recordings. A similar effect was found for the PAT-derived respiratory disturbance index with a reduction from 31.2±16.5/h to 21.7±14.4/h (p<0.001), for automated and manual scoring, respectively. A lower pAHI for manual scoring was found in all body positions and sleep stages and was independent of gender and body mass index. The absolute difference of pAHI increased with sleep apnea severity, while the relative difference decreased. Pearson's correlation coefficient between pAHI and oxygen desaturation index (ODI) significantly improved from 0.89 to 0.94 with manual scoring (p<0.001). CONCLUSIONS: Manual scoring results in a lower pAHI while improving the correlation to ODI. With manual scoring, the OSA category decreases in a clinically relevant proportion of patients. Sleep stages and time do not change significantly with manual scoring. In the authors' opinion, manual oversight is recommended if clinical decisions are likely to change.

Essential Hypertension and Oxidative Stress: Novel Future Perspectives.

Among cardiovascular diseases, hypertension is one of the main risk factors predisposing to fatal complications. Oxidative stress and chronic inflammation have been identified as potentially responsible for the development of endothelial damage and vascular stiffness, two of the primum movens of hypertension and cardiovascular diseases. Based on these data, we conducted an open-label randomized study, first, to evaluate the endothelial damage and vascular stiffness in hypertense patients; second, to test the effect of supplementation with a physiological antioxidant (melatonin 1 mg/day for 1 year) in patients with essential hypertension vs. hypertensive controls. Twenty-three patients of either gender were enrolled and randomized 1:1 in two groups (control and supplemented group). The plasmatic total antioxidant capacity (as a marker of oxidative stress), blood pressure, arterial stiffness, and peripheral endothelial function were evaluated at the beginning of the study and after 1 year in both groups. Our results showed that arterial stiffness improved significantly (p = 0.022) in supplemented patients. The endothelial function increased too, even if not significantly (p = 0.688), after 1 year of melatonin administration. Moreover, the supplemented group showed a significative reduction in TAC levels (p = 0.041) correlated with the improvement of arterial stiffness. These data suggest that melatonin may play an important role in reducing the serum levels of TAC and, consequently, in improving arterial stiffness.

Diagnostic accuracy of home sleep apnea testing using peripheral arterial tonometry for sleep apnea: A systematic review and meta-analysis.

This study aimed to evaluate the diagnostic accuracy of home sleep apnea testing using peripheral arterial tonometry for sleep apnea as an alternative to polysomnography. We conducted a systematic review and meta-analysis of observational studies, randomized controlled trials, and diagnostic case-control studies examining the diagnostic accuracy of peripheral arterial tonometry by searching the CENTRAL, MEDLINE, EMBASE, ICTRP and ClinicalTrials.gov databases on 5 October 2021. We assessed the risk of bias of the included studies using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. A bivariate random-effects model was generated to derive the summary point estimates of sensitivity and specificity with 95% confidence intervals at different apnea-hypopnea index cutoffs. This meta-analysis included 13 studies (1227 participants, median prevalence of sleep apnea with apnea-hypopnea index ≥ 5 events per hr: 85%). The risk of bias in the included studies was low to moderate. The pooled sensitivity and specificity estimates were 96% (95% confidence interval: 93%-97%) and 44% (95% confidence interval: 32%-56%) at apnea-hypopnea index ≥ 5 events per hr, 88% (85%-91%) and 74% (63%-83%) at apnea-hypopnea index ≧ 15 events per hr, and 80% (66%-89%) and 90% (83%-95%) at apnea-hypopnea index ≧ 30 events per hr, respectively. Peripheral arterial tonometry resulted in a significant number of false negatives and false positives at any apnea-hypopnea index cutoff when applied to the median prevalence setting of the included studies. The inadequate sensitivity and specificity of peripheral arterial tonometry render it an unsuitable alternative to polysomnography for detecting sleep apnea for apnea-hypopnea index ≧ 5, 15 and 30 events per hr.

Early Signs of Microvascular Endothelial Dysfunction in Adolescents with Newly Diagnosed Essential Hypertension.

Endothelial dysfunction represents one of the key pathomechanisms in many diseases, including hypertension. Peripheral arterial tonometry (PAT) evaluates the functional status of microvascular endothelium and offers a biomarker of early, potentially reversible, vascular damage. This study aimed to assess endothelial function using conventional and novel indices of PAT in pediatric hypertensives. As such, 100 adolescents with normal blood pressure, and essential and white-coat hypertension were examined using EndoPAT 2000. Conventional reactive hyperemia index (RHI) and novel indices of hyperemic response, including the area under the curve of hyperemic response (AUC), were evaluated. AUC was the only parameter sensitive to the effect of hypertension, with significantly lower values in essential hypertensives compared to normotensives and white-coat hypertensives (p = 0.024, p = 0.032, respectively). AUC was the only parameter significantly correlating with mean ambulatory monitored blood pressure (r = -0.231, p = 0.021). AUC showed a significant negative association with age (p = 0.039), but a significant positive association with pubertal status indexed by plasma levels of dehydroepiandrosterone (p = 0.027). This is the first study reporting early signs of microvascular endothelial dysfunction evaluated using PAT in adolescents with newly diagnosed essential hypertension. Detailed analysis of hyperemic response using overall magnitude indexed by AUC provided a more robust method compared to the conventional evaluation of RHI.

Home sleep apnea testing with peripheral arterial tonometry to assess outcome in upper airway stimulation.

STUDY OBJECTIVES: To determine whether home sleep apnea testing with peripheral arterial tonometry (HSAT-PAT) can be used in upper airway stimulation to evaluate therapy success. METHODS: Data analysis from 50 consecutive patients receiving upper airway stimulation was performed. Baseline values were measured by polysomnography and HSAT-PAT. Follow-up was performed during and after titration (3-6 months) by polysomnography and HSAT-PAT and after 1 year by HSAT-PAT only. Primary outcome measures were reduction in the apnea-hypopnea index and oxygen desaturation index. In addition, an analysis of night-to-night variability for HSAT-PAT was performed. RESULTS: All 50 patients completed their posttitration visit (3-6 months) and 41 patients completed the 1-year follow-up. In HSAT-PAT after 1 year, the mean apnea-hypopnea index (desaturation 3%) was reduced from 29.5 ± 17.1 events/h to 19.9 ± 13.1 events/h (P < .01) and the oxygen desaturation index (desaturation 4%) was reduced from 17.8 ± 12.6 events/h to 10.2 ± 8.3 events/h (P < .01). Therapy adherence after 1 year was high (6.6 ± 1.9 hours per night) and led to improvement in daytime sleepiness, meaning a reduction in the Epworth Sleepiness Scale score from 12.8 ± 5.4 to 5.9 ± 4.0 (P < .01). Analysis of night-to-night variability showed similar apnea-hypopnea index values between the 2 nights. CONCLUSIONS: Upper airway stimulation was able to reduce the apnea-hypopnea index and oxygen desaturation index after 1 year, as assessed by full-night efficacy studies with HSAT-PAT. In addition, improvements in self-reported outcome parameters were observed. The importance of publishing the scoring criteria is highlighted and whether data are based on full-night efficacy studies or a selected period of time from a sleep study. This is a prerequisite for comparing data with other trials in the emerging field of upper airway stimulation. CITATION: Hinder D, Schams SC, Knaus C, Tschopp K. Home sleep apnea testing with peripheral arterial tonometry to assess outcome in upper airway stimulation. J Clin Sleep Med. 2022;18(9):2197-2205.

Performance comparison of peripheral arterial tonometry-based testing and polysomnography to diagnose obstructive sleep apnea in military personnel.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is increasingly common among military personnel, but diagnostic capabilities are challenged by limited capability for polysomnography (PSG). We sought to evaluate the diagnostic properties of peripheral arterial tonometry (PAT)-based home sleep apnea testing (HSAT) to accurately identify and classify OSA among active-duty military personnel. METHODS: This study was a retrospective review of all patients suspected of having OSA who completed an initial PAT-based HSAT followed by confirmatory PSG within 120 days. The diagnostic properties of a PAT-based, HSAT-derived apnea-hypopnea index (AHI) vs a PSG-derived AHI were assessed. RESULTS: Two hundred eight matched pairs of asynchronous studies were analyzed. The prevalence of OSA was 63.5%. PAT-based HSAT overdiagnosed 27.4% of patients with OSA and underdiagnosed 46.6% of patients with OSA. The majority (n = 116, 55.8%) of patients changed OSA severity classification (absent, mild, moderate, severe) after PSG. OSA severity classification concordance between PAT-based HSAT and PSG was observed in 53.4%, 40.5%, 28.6%, and 40.0% of patients with absent, mild, moderate, and severe OSA, respectively. Receiver operating characteristic curve analysis showed an area under the curve of 0.715 and a proposed PAT-based, HSAT-derived AHI cutoff score for OSA diagnosis of 9.0 events/h. This PAT-based, HSAT-derived AHI provided a 52% sensitivity, 83% specificity, 84% positive predictive value, and 50% negative predictive value. Bland-Altman plots showed an unacceptable degree of agreement between PAT-based, HSAT-derived AHI and AHI. CONCLUSIONS: There is significant discordance between PAT-based HSAT and PSG among active-duty military personnel evaluated for OSA. PAT-based HSAT may have limited utility for diagnosing OSA and grading severity in this unique patient population. CITATION: O'Reilly BM, Wang Q, Collen J, Matsangas P, Colombo CJ, Mysliwiec V. Performance comparison of peripheral arterial tonometry-based testing and polysomnography to diagnose obstructive sleep apnea in military personnel. J Clin Sleep Med. 2022;18(6):1523-1530.

A multicentric validation study of a novel home sleep apnea test based on peripheral arterial tonometry.

STUDY OBJECTIVES: This paper reports on the multicentric validation of a novel FDA-cleared home sleep apnea test based on peripheral arterial tonometry (PAT HSAT). METHODS: One hundred sixty-seven participants suspected of having obstructive sleep apnea (OSA) were included in a multicentric cohort. All patients underwent simultaneous polysomnography (PSG) and PAT HSAT, and all PSG data were independently double scored using both the recommended 1A rule for hypopnea, requiring a 3% desaturation or arousal (3% Rule), and the acceptable 1B rule for hypopnea, requiring a 4% desaturation (4% Rule). The double-scoring of PSG enabled a comparison of the agreement between PAT HSAT and PSG to the inter-rater agreement of PSG. Clinical endpoint parameters were selected to evaluate the device's ability to determine the OSA severity category. Finally, a correction for near-boundary apnea-hypopnea index values was proposed to adequately handle the inter-rater variability of the PSG benchmark. RESULTS: For both the 3% and the 4% Rules, most endpoint parameters showed a close agreement with PSG. The 4-way OSA severity categorization accuracy of PAT HSAT was strong, but nevertheless lower than the inter-rater agreement of PSG (70% vs 77% for the 3% Rule and 78% vs 81% for the 4% Rule). CONCLUSIONS: This paper reported on a multitude of robust endpoint parameters, in particular OSA severity categorization accuracies, while also benchmarking clinical performances against double-scored PSG. This study demonstrated strong agreement of PAT HSAT with PSG. The results of this study also suggest that different brands of PAT HSAT may have distinct clinical performance characteristics.