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Aging is associated with reductions in endothelial function, observations primarily reported using brachial artery ultrasound. There is growing interest in the use of peripheral artery tonometry (PAT) of microvessels in the fingertip to assess endothelial function because it is less technically demanding and has a high sensitivity and specificity for assessing coronary endothelial function. Moreover, similar to brachial artery flow-mediated dilation (FMD), PAT predicts cardiovascular disease outcomes. However, the relationship between PAT and FMD have yet to be examined in the context of aging. To address this question, reactive hyperemic index (RHI) using EndoPAT and FMD using brachial artery ultrasound were assessed after 5 min of forearm ischemia in 20 younger (18–40 yr old; 29 ± 4 yr) and 20 older (60–75 yr old; 65 ± 4 yr) healthy adult men. Higher values of both FMD and RHI indicate better endothelial function. Endothelial function assessed via brachial artery FMD was lower in older (4.8 ± 2.1%), compared with younger (7.5 ± 1.6%) men (P < 0.001). In contrast, the RHI assessed via PAT was greater in older (2.2 ± 0.6), compared with younger (1.8 ± 0.5) men (P = 0.014). FMD and RHI were not correlated (r = –0.15; P = 0.35). We conclude that PAT may not be an appropriate measure to evaluate age-associated changes in endothelial function. NEW & NOTEWORTHY Microvessel endothelial function assessed via finger plethysmography may not reflect age-associated reductions in large artery endothelial function assessed via brachial artery flow-mediated dilation.

Endothelial function has diagnostic, prognostic and therapeutic significance. A number of non-invasive techniques were introduced for its assessment, including flow-mediated dilation (FMD), finger plethysmography (RH-PAT) and digital thermal monitoring (DTM). All these methods can be performed simultaneously. In addition, various methods for measuring arterial wall stiffness are available such as: pulse wave analysis (PWA), pulse wave velocity (PWV), pulse contour analysis (PCA) and carotid wall distensibility coefficient (DC). Finally, carotid intima-media thickness (cIMT) and ankle brachial index (ABI) are used as surrogate read-outs of atherosclerosis. Here, we briefly describe the advantages, limitations and interrelationships of various methods used for the assessment of endothelial function, arterial stiffness, and present the concept of an integrated evaluation of vascular health based on multiple methods. This strategy may be useful to stratify cardiovascular risk and represents a step towards multiparametric assessment of endothelium for effective endothelium-guided therapy in patients with cardiovascular diseases.

The study aims at assessing the changes in electroencephalography (as measured by the A-phases of cyclic alternating pattern) and autonomic activity (based on pulse wave amplitude) at the recovery of airway patency in patients with obstructive sleep apnea syndrome. Analysis of polysomnographic recordings from 20 male individuals with obstructive sleep apnea syndrome was carried out in total sleep time, non-rapid eye movement and rapid eye movement sleep. Scoring quantified the combined occurrence (time range of 4 s before and 4 s after respiratory recovery) or separate occurrence of A-phases (cortical activation), and pulse wave amplitude drops (below 30%) to apneas, hypopneas or flow limitation events. A dual response (A-phase associated with a pulse wave amplitude drop) was the most frequent response (71.8% in total sleep time) for all types of respiratory events, with a progressive reduction from apneas to hypopneas and flow limitation events. The highly significant correlation in total sleep time (r = 0.9351; P

A major symptom of hand-arm vibration syndrome is a secondary Raynaud’s phenomenon—vibration white finger (VWF)—which results from a vasospasm of the digital arteries caused by work with vibration devices leading to occupational disease. Pharmacotherapy of VWF is often ineffective or has adverse effects. The aim of this work was to verify the influence of inhalation of partially ionized oxygen (O2•−) on peripheral blood vessels in the hands of patients with VWF. Ninety one (91)patients with VWF underwent four-finger adsorption plethysmography, and the pulse wave amplitude was recorded expressed in numeric parameters—called the native record. Next, a cold water test was conducted following with second plethysmography. The patients were divided in to the three groups. First and second inhaled 20-min of ionized oxygen O2•− or oxygen O2 respectively. Thirth group was control without treatment. All three groups a follow-up third plethysmography—the post-therapy record. Changes in the pulse wave amplitudes were evaluated. Inpatients group inhaling O2•− a modest increase of pulse wave amplitude was observed compared to the native record, patients inhaling medical oxygen O2 and the control showed a undesirable decline of pulse wave amplitude in VWF fingers. Strong vasodilatation were more frequent in the group inhaling O2•− compare to O2 (p &lt, 0.05). Peripheral vasodilatation achieved by inhalation of O2•− could be used for VWF treatment without undesirable side effect in hospital as well as at home environment.

Several continuous cardiac output (CO) monitoring systems have been developed. None are ideal for use in anaesthesia or critical care. They all lack precision as shown by Bland–Altman studies. However, some provide reliable CO trending, which is useful for guiding fluid optimization protocols. The key issue is which systems are reliable, and this has not been helped by a lack of understanding of validation statistics in the literature. Recent studies suggest that none of the current intra-arterial pulse contour systems trend CO reliably. Stroke volume variability may provide a reliable alternative. Strangely, Nexfin finger plethysmography did reliably trend CO during routine surgery, but not during critical care. BioReactance also appears to trend CO acceptably, but its performance is affected by certain types of surgery that alter the pathways of electrical flux. Oesophageal Doppler is now well established for guiding goal-directed fluid regimens, and its trending of CO changes seems reliable.

In healthy subjects, variation in cardiovascular responses to sympathetic stimulation evoked by submaximal lower body negative pressure (LBNP) is considerable. This study addressed the question whether inter-subject variation in cardiovascular responses coincides with consistent and reproducible responses in an individual subject. In 10 healthy subjects (5 female, median age 22 years), continuous hemodynamic parameters (finger plethysmography; Nexfin, Edwards Lifesciences), and time-domain baroreflex sensitivity (BRS) were quantified during three consecutive 5-min runs of LBNP at −50 mmHg. The protocol was repeated after 1 week to establish intra-subject reproducibility. In response to LBNP, 5 subjects (3 females) showed a prominent increase in heart rate (HR; 54 ± 14%, p = 0.001) with no change in total peripheral resistance (TPR; p = 0.25) whereas the other 5 subjects (2 females) demonstrated a significant rise in TPR (7 ± 3%, p = 0.017) with a moderate increase in HR (21 ± 9%, p = 0.004). These different reflex responses coincided with differences in resting BRS (22 ± 8 vs. 11 ± 3 ms/mmHg, p = 0.049) and resting HR (57 ± 8 vs. 71 ± 12 bpm, p = 0.047) and were highly reproducible over time. In conclusion, we found distinct cardiovascular response patterns to sympathetic stimulation by LBNP in young healthy individuals. These patterns of preferential autonomic blood pressure control appeared related to resting cardiac BRS and HR and were consistent over time.

A B S T R A C T In the fight against cardiovascular diseases, preventive strategies are becoming the focus of attention. One of these strategies proposes to identify individuals who are at a high risk of developing cardiovascular disease. Endothelial dysfunction could improve patient risk stratification and the implementation of preventive strategies. In this review we focus on noninvasive techniques that have recently become available to assess endothelial function: flow-mediated vasodilation as measured by ultrasound of the brachial artery, pulse wave analysis, and finger plethysmography during postischemic hyperemia. We describe the basic principles, the main protocols to perform these techniques, and their clinical value based on the scientific evidence.

Summary Background: The aims of this study were to establish the optimum duration of blood flow occlusion to obtain maximal response and to compare the response after lower-arm and upper-arm occlusion. Methods: Pulse wave amplitude was analysed using a novel finger plethysmograph (EndoPat; Itamar). For measuring reactive hyperaemic index (RHI) induced by forearm cuff occlusion, 30 healthy subjects were examined at different days in a random order of four cuff occlusion times (1·5, 3, 5 and 8 min). RHI induced by 5 min upper-arm cuff occlusion was also measured in 20 subjects. Results: Average RHI was lower with 1·5 and 3 min forearm occlusion compared with 8 min forearm occlusion (P = 0·002 and P = 0·024). There was no significant difference between values of 5 min and 8 min forearm occlusion and between 5 min forearm and 5 min upper-arm occlusion (P = 0·1). All subjects reported less discomfort after forearm occlusion compared with upper-arm occlusion. Conclusion: Maximum response was reached after 5 min of blood flow occlusion and therefore this occlusion time is recommended. The response after forearm and upper-arm occlusion did not differ significantly. Forearm occlusion might be preferred as this caused less discomfort.

Background Finger plethysmography and thermometry are objective measures used to assess the vascular aspect of hand-arm vibration syndrome (HAVS). Research to date shows poor correlation between these tests and Stockholm Workshop Scale (SWS) vascular stage. Clinicians, researchers and compensation boards require objective means to diagnose and quantify HAVS. Aims To define the specificity and sensitivity of thermometry and plethysmography using the SWS as the reference criterion. A secondary goal was to consider cut points for the tests optimizing sensitivity and specificity. Methods A cross-sectional analysis was conducted on HAVS patients seen at an occupational medicine specialty clinic. Plethysmography and thermometry were analyzed using SWS vascular stage as the outcome variable. Logistic regression controlled for age, smoking and time since last vibration exposure and use of vasoactive medications. The sensitivity and specificity of the combined tests were calculated using varying cut points. Results A total of 139 patients consented to participate in the study. Plethysmography stage 1 or greater showed the highest sensitivity (sensitivity 94% and specificity 15%). Specificity was optimized combining plethysmography stage 3 and thermometry stage 3 (specificity 98% and sensitivity 23%). Maximal diagnostic accuracy was achieved by plethysmography alone setting the criteria for a positive test as being stage 1 or greater (70%). Conclusions Neither plethysmography nor thermometry either alone or in combination demonstrated sufficient sensitivity and specificity to serve as an objective correlate for SWS vascular stage. All combinations of plethysmography and thermometry showed a lower specificity than sensitivity indicating that the SWS may be less sensitive in detecting vascular pathology than the objective tests.

Successful treatment of cough syncope depends on the correction of various pathogenetic mechanisms among different patients. The valsalva maneuver (VM), which elicits hemodynamic responses mimicking coughs, has potential for investigating the individual pathogenesis of cough syncope. Eighteen consecutive patients suffering from cough-induced syncope were examined. All patients were asked to cough and to perform VM several times under continuous cerebral blood-flow velocity and blood pressure (BP) monitoring by transcranial Doppler and finger plethysmography. Eight patients demonstrated abnormal VM characterized by the absent BP overshoot following the relief of straining. Patients demonstrating abnormal VM had delayed BP recovery after cough (median, 16.4; range, 8.7–25.6 seconds) compared to those demonstrating normal VM (2.6, 1.3–3.8 seconds, p < 0.001). Seven of the 10 patients exhibiting normal BP overshoot during VM had stenotic arterial lesions in the cerebral or coronary circulation, whereas only one of the eight patients demonstrating absent BP overshoot had coronary artery disease (70% vs. 12.5%, p = 0.025). Other clinical profiles, body mass index, frequency of obstructive pulmonary disease and valsalva ratio did not differ between patients featuring normal and absent BP overshoot. In conclusion, the pathogenesis of cough syncope could be different between patients with normal and abnormal VM responses. Patients who had no BP overshoot during VM sustained prolonged hypotension after cough. The VM helps in discriminating among pathogenic mechanisms and guiding investigation and treatment for cough syncope patients.

Das obstruktive Schlafapnoesyndrom ist eine in der westlichen Welt häufige Erkrankung, die mit einem erhöhten Risiko für kardiovaskuläre Erkrankungen einhergeht. Es wird davon ausgegangen, dass durch Hypoxie, Sympathikuserhöhung und thorakalem Scherstress eine endotheliale Dysfunktion verursacht wird. Dennoch ist nicht abschließend geklärt, ob die obstruktive Schlafapnoe alleine für diese Tatsache verantwortlich sein kann oder ob ein Zusammenhang aufgrund der häufigen Komorbiditäten (arterielle Hypertonie, Diabetes mellitus oder Adipositas) lediglich so erscheinen mag. In dieser Arbeit wurde versucht, mit einer nicht-invasiven Methode die Auswirkungen des obstruktiven Schlafapnoesyndroms auf das vaskuläre Endothel zu beurteilen. Dabei wurde darauf geachtet, dass die Studienteilnehmer neben einer obstruktiven Schlafapnoe keine weiteren Erkrankungen hatten, um mögliche Fehlerquellen ausschließen. Es wurden zwei Gruppen untersucht, wobei die ausschließlich männlichen Teilnehmer zwischen 18 und 65 Jahren sein sollten und keine kardiovaskulären Nebenerkrankungen haben durften. Die OSA-Gruppe mit 38 Teilnehmern sollte einen AHI von >5/h haben (AHI: 24,00/h ± 22,4/h), die Kontrollgruppe mit 34 Teilnehmern sollte einen AHI von ≤5/h (AHI: 2,1/h ± 1,4/h). Bei jeweils gleichen Untersuchungsbedingungen erfolgte eine abendliche Messung der Endothelfunktion und der Gefäßsteifigkeit mittels Fingerplethysmographie (EndoPAT™ 2000, Itamar). Im Anschluss wurde eine mindestens 6-stündige kardiorespiratorische Polysomnographie durchgeführt, um unmittelbar nach Wecken des Probanden eine zweite EndoPAT™-Messung durchzuführen. Es herrschten stets gleiche Bedingungen für beide Gruppen, die Messmethode wurde standardisiert für jeden Probanden genau gleich durchgeführt. Mittels der EndoPAT™-Messung wurde der RHI als Parameter für die endotheliale Funktion gemessen, der Augmentationsindex wurde als Parameter für die Gefäßsteifigkeit gemessen. Die Berechnung der jeweiligen Werte erfolgte durch die geräteeigene Software (Itamar). Die Ergebnisse der Polysomnographie wurden durch medizinisch technische Assistenten nach den Richtlinien der DGSM ausgewertet und dokumentiert. Ziel der Studie war es erstens aufzuzeigen, dass Patienten mit Schlafapnoe eine schlechtere endotheliale Funktion und eine höhere Gefäßsteifigkeit haben und zweitens, dass sich diese Eigenschaften während der Nacht durch die nächtlichen Hypoxiephasen beim Patienten mit Schlafapnoe negativ auswirkt. In beiden Punkten konnten in der vorliegenden Studie keine signifikanten Unterschiede aufgezeigt werden, wenngleich Tendenzen erkennbar sind, welche die Primär- und Sekundärhypothesen stützen. Wie bereits in verschiedenen anderen Arbeiten beobachtet, zeigt sich auch in unserem Kollektiv eine Korrelation zwischen Alter und Gefäßsteifigkeit. In unserer Studie konnte ein veränderter Gefäßstatus bei Patienten mit moderater obstruktiver Schlafapnoe nicht endgültig dargestellt werden. Abschließend ist für künftige Studien zu diesem Thema ein erweitertes Kollektiv zu empfehlen. Zudem sollten die Einschlusskriterien vor allem beim Lebensalter enger gefasst werden, um eine mögliche Fehlerquelle zu eliminieren., Obstructive sleep apnea (OSA) is a very common sleep disorder in the western civilization, which carries an increased risk of developing cardiovascular diseases. It is assumed, that hypoxia, sympathetic stress levels and thoracic shear stress may contribute to the development of endothelial dysfunction. Since patients suffering from obstructive sleep apnea, commonly also suffer from other comorbidities, particularly arterial hypertension, diabetes mellitus and obesity, there is not absolute certainty, that a sleep disorder alone is responsible for a loss of endothelial function. The aim of this study was to measure the consequences of obstructive sleep apnea on the vascular endothelium with a non-invasive method. We examined two groups of male patients between the ages of 18 and 65 who did not suffer from any cardiovascular diseases. To reduce any bias, we tried to exclude patients with any comorbidities. We included 38 patients with a median apnea hypopnea index (AHI) of 22,0 ± 22,4/h in the OSA-group (AHI≥5/h), and in the control-group (AHI≤5/h) 34 patients with a median AHI of 2,1 ± 1,4/h. In similar surroundings and under similar conditions we then performed the first EndoPAT™2000 measurement, followed by a polysomnography for at least 6 hours and another EndoPAT™2000 measurement. By measuring the reactive hyperaemic index (RHI) we received a parameter for evaluating the endothelial function. The arterial stiffness was assessed by measuring the augmentation index (AI). The RHI and AI were calculated through the use of the EndoPAT™2000-software, while the polysomnography was analyzed by experienced medical staff according to the DGSM-guidelines. The primary objective of the study was to show, that patients with obstructive sleep apnea have an impaired arterial stiffness and endothelial function. Another aim was to show, that the both functions decline during the night. Despite not finding significant differences, we did however see encouraging tendencies to prove our theories. Similar to the results of other studies we could show a correlation between age and arterial stiffness. For further studies we suggest a bigger collective of a more similar background regarding age and medical history. Moreover, the OSA-group should consist of patients suffering from severe OSA.

Eight patients with Raynaud's phenomenon were entered into a double-blind crossover study of nifedipine versus placebo, with 7 patients undergoing finger plethysmography before and after sublingual nifedipine administration. While receiving nifedipine, all patients reported decreased frequency and severity of attacks, and 4 of 5 had digital ulcer healing. Total finger blood flow increased 5 of 6 patients after treatment with sublingual nifedipine. This preliminary study indicates that nifedipine may be a useful agent for treatment of digital vasospasm.

In patients with heart failure, left ventricular systolic dysfunction and prolonged QRS complex, cardiac resynchronization therapy (CRT) is a treatment method aimed at restoration of myocardial depolarization synchronicity. However, the extent of clinical and echocardiographic improvement depends on anatomical relations in individual patients, on structural changes in the heart, on intrinsic electrical activation, and on the position of pacing leads. Many parameters of CRT devices may be changed in order to tailor the function of CRT to the needs of a particular patient; the most important among them is AV and VV interval. The largest trials studying CRT used various methods for optimization of these intervals but unequivocal proof of the benefit brought by optimization is still lacking. Many methods were evaluated, most frequently based on echocardiography and intracardiac electrogram interval measurement. However, drawbacks in statistics make the studies of limited value for establishing a reference method or guidance for daily practice. Echocardiography has inherent variability of results and is highly operator dependent. Optimization based on intracardiac electrogram intervals has not proved yet to be of clear benefit above arbitrary AV interval. The most promising method is hemodynamic assessment by finger plethysmography. Measured data are highly reproducible and operator-independentA randomized multicenter double-blind study using finger plethysmography is needed to prove the value of this method and of CRT optimization in general. The measurement of information content in any data suitable for CRT optimization, analysis of reproducibility and general usage of confidence intervals may show other methods appropriate for it, too. The cooperation with a statistician is oftentimes a necessity.

An attempt was made to analyze differences in the results obtained by various kinds of finger plethysmography, such as penetration photo-electric plethysmograph (penet.-PTG), reflexion photo-electric PTG (refl.-PTG), mechanoelectric PTG (pneumo-PTG and hydro-PTG) and impedance PTG, by taking simultaneous recordings principally from the same finger tip. Comparisons of the time course (onset time and crest time) and the wave form (harmonic analysis and base line deviation) of each pulse wave were made with the standard records of the penet.-PTG depicted simultaneously. Experiments were repeated on 15 healthy adults. No significant differences were observed in the time course and wave form among the records obtained by various kinds of plethysmographs, so far as the records obtained from the finger tip were concerned, whereas appreciable differences were recognized in the time course as well as in the wave form, when the proximal phalange of the finger was involved in the plethysmograph, the whole finger cup being employed for mechanoelectric PTG, or one of the electrodes being placed at the proximal phalange for impedance PTG.