Caracterização da complacência intracraniana e sua resposta à mudança postural em indivíduos na fase crônica do Acidente Vascular Cerebral

Abstract

Stroke is considered one of the leading causes of death and disability globally. Unfortunately, most survivors do not return to their activities fully, causing a burden to the public system due to the costs of hospitalization, rehabilitation, and social security, with the risk of having a recurrent stroke within the first five years. After the stroke, the individual starts to compose sedentary lifestyle habits due to incapacity or changes in routine. It is known that stroke and sedentary lifestyle generate changes in the cardiovascular system and the regulation of cerebral blood flow (CBF), which may explain the risk for new cerebrovascular events. Among the regulatory components of CBF, there is intracranial pressure (ICP) and intracranial compliance (ICC). Developing innovative ways to monitor ICP and ICC is of clinical interest for critical care medicine and neurological and cardiovascular rehabilitation. Non-invasive monitoring tools open perspectives to understand cerebral hemodynamics in chronic and disabling situations and can help prevent, early diagnosis, or even guide a rehabilitation program. In addition, the relationship with the ICC is still little explored, with the variability of concepts and measures. Given this scenario, the thesis addresses in the first manuscript a scoping review on the ideas and methodologies of intracranial compliance and in the second manuscript the characterization of intracranial compliance in the chronic phase of stroke. In the first manuscript, it was found that most studies reported the concept of compliance as related to volume and pressure variations or their inverse (elastance), mainly in the intracranial compartment. In addition, terms such as “accommodation,” “compensation,” “reserve capacity,” and “buffering capacity” were used to describe the clinical interpretation. The second part of this review described the techniques (invasive and non-invasive) and outcomes used to measure ICC. The most used method was the invasive, representing 57-88% of the studies. The most evaluated variables were ICP, mainly absolute values or pulse amplitude. ICP waveforms should be further explored, together with the potential of non-invasive methods since different aspects of ICC can be measured. The second manuscript was a cross-sectional study composed of 33 individuals with chronic post-stroke and 33 without neurological alterations and sedentary behavior. The evaluations were carried out in 2 days, respecting one week between each. The sensorimotor impairment of post-stroke volunteers, walking speed, physical activity level, intracranial pressure, and compliance of both groups were assessed. When comparing ICP wave peaks and inactivity time within and between groups, no significant differences were identified, with differences in walking speed and number of steps present. The present study concludes that individuals in the post-stroke chronic phase with sedentary behaviors positively respond to

intracranial compliance during rest and active postural change. This finding expands the possibility of using intracranial compliance assessment methods in other therapeutic approaches, such as prescription and intensity of a rehabilitation program. In addition, ICC monitoring can be considered a complementary resource to ICP monitoring and clinical examination.