Intracranial compliance in type 2 diabetes mellitus and its relationship with the cardiovascular autonomic nervous control

The intracranial compliance in type 2 diabetes mellitus (T2DM) patients and the association with cardiovascular autonomic control have not been fully elucidated. The aim of this study was to assess intracranial compliance using the noninvasive intracranial pressure (niICP) and the monitoring of waveform peaks (P1, P2, and P3) and the relationship with cardiovascular autonomic control in T2DM patients. Thirty-two men aged 40-60 years without cardiovascular autonomic neuropathy (CAN) were studied: T2DMG (n=16) and control group CG (n=16). The niICP was evaluated by a noninvasive extracranial sensor placed on the scalp. Cardiovascular autonomic control was evaluated by indices of the baroreflex sensitivity (BRS), from temporal series of R-R intervals of electrocardiogram and systolic arterial pressure, during supine and orthostatic positions. The participants remained in the supine position for 15 min and then 15 min more in orthostatism. T2DMG presented a decrease of the P2/P1 ratio during the orthostatic position (P<0.001). There was a negative moderate correlation between the P2 peak with cardiovascular coupling (K²_HP-SAPLF) in supine (r=-0.612, P=0.011) and orthostatic (r=-0.568, P=0.020) positions in T2DMG. We concluded that T2DM patients without CAN and cardiovascular complications presented intracranial compliance similar to healthy subjects. Despite preserved intracranial adjustments, T2DM patients had a response of greater magnitude in orthostatism. In addition, the decoupling between the heart period and blood pressure signal oscillations in low frequency appeared to be related to the worsening of intracranial compliance due to the increased P2 peak.

Correlation between maximal aerobic power and longitudinal vital signals during high-intensity activities of daily living

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): São Paulo Research Foundation (FAPESP);Coordination for the Improvement of Higher Education Personnel (CAPES)

Background

Higher activity levels are linked with better cardiovascular health. Maximum aerobic power (measured by the maximal oxygen uptake, VO2max) obtained during cardiopulmonary exercise testing (CPET) is an index of cardiovascular health and represents the maximum ability of the aerobic system to supply energy. Moreover, it is known that high-intensity activities of daily living (hiADL) are associated with higher VO2max, and were three times more beneficial than low-intensity activities, such as light walking. However, little is known about the physiological responses during these hiADL that are associated with better health outcomes. So far, only the levels and intensities of the physical activities have been investigated, but the physiological responses at these activities remain unclear.

Purpose

Verify the associations between VO2max and longitudinal vital signals from wearables during hiADL.

Methods

43 volunteers (32 males, 39.91±15.87 years; 75.41±13.12 kg; 173.67±9.04 cm) with different levels of VO2max (31.08±8.73 ml/kg/min) wore a wearable device (smart t-shirt, Hexoskin) with embedded cardiac, respiratory, and movement sensors to collect unobtrusive data for 7 days (9.31±1.36 hours per day). These sensors continuously measure heart rate (HR), breathing rate (BR), minute ventilation (VE), tidal volume (Vt), hip acceleration (ACC), and walking cadence (Cad). The hiADL were classified based on the Cad response where values higher than 124 steps per minute were labelled as hiADL. At hiADL, the average response for all variables was calculated. Finally, the Pearson or Spearman correlations were computed considering a statistical significance level of 5%.

Results

hiADL corresponded to just 1% of the physical activities (or 35.11±43.30 minutes per week). The average response of the vital signals at hiADL were: HR (118.2±20.36 bpm), BR (30.7±8.0 rpm), VE (52.21±35.54l), Vt (1.63±0.71 l/min), Acc (0.87±0.6g), and Cad (143.69±10.13). The correlations were statistically (p&lt;0.05) high and positive between VO2max and BR, VE, Vt, and Cad; also, moderate, and positive between VO2max and HR and with the percentage of the time spent at hiADL, as described in figure 1.

Conclusion

The VO2max (or cardiovascular health) is related to the time spent in hiADL and with the hemodynamic and respiratory response magnitudes at these high-intensity activities.

Cerebral oxygenation during cardiopulmonary exercise testing of patients with cardiovascular and respiratory diseases: a systematic review

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): National Council for Scientific and Technological Development - CNPq (310612/2019-5) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES (001)

Background

Cardiopulmonary exercise testing (CPET) has been widely used in clinical practice to determine aerobic capacity and assess the integrity of cardiovascular, respiratory, muscular and neurohumoral adjustments in health and disease. However, little is known about the acute cerebral oxygenation responses during CPET in cardiorespiratory patients, to increase safety for the physical intervention protocols development.

Purpose

To conduct a systematic review to evaluate the cerebral oxygenation acute responses during CPET in patients with cardiovascular, metabolic or respiratory diseases.

Methods

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Five electronic databases PubMed, Scopus, Web of Science, Embase and Cinahal were searched from the inception to November 10th, 2021. The eligibility criteria were determined considering the PICOS format: patients with heart, metabolic or respiratory disease (P); who carried out incremental CPET (I); compared with healthy subjects (C); our results of interest were cerebral oxygenation response through near-infrared spectroscopy (NIRS) (O); in cross-sectional studies (S). The articles were independently selected by two researchers and the disagreements were solved by a third researcher. The ROBINS I scale assessed the risk of bias of the eligible studies.

Results

The initial search identified 3557 articles and 4 additional articles were identified through other sources (references of eligible articles). After screening and deleting the duplicated articles, 7 studies were included. The studies were classified as moderate risk of bias and the most questioned domains were due to outcome measurement and due to selection of reported result. This systematic review analyzed 428 individuals, 305 men and 123 women aged between 43 to 70 years. Of these, 247 had diagnosis of cardiovascular disease (101 with heart failure NYHA II and III; 77 idiopathic dilated cardiomyopathy; 33 valvular disease; 25 coronary artery disease; 22 pulmonary arterial hypertension); 15 with severe obstructive sleep apnea and 166 apparently healthy. No article was found with metabolic disease. The results showed impairment of cerebral oxygenation, evaluated by NIRS, in patients with cardiovascular diseases during the CPET compared with healthy individuals. On the other hand, severe obstructive sleep apnea was not related with a poorer cerebral oxygenation during CPET.

Conclusion

The acute CPET response negatively impacts the cerebral oxygenation in patients with cardiovascular diseases. Taking into account the considered risk of bias of the included studies, more attention is necessary to ensure greater safety for testing maximal exercise in cardiac patients.