Cerebral oxygenation during cardiopulmonary exercise testing of patients with cardiovascular and respiratory diseases: a systematic review
Authors: Aguiar Mesquita Galdino G , Rehder-Santos P , Nogueira Linares S , Beltrame T , Catai AM 
Published: May 2022

Abstract

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.