The Autonomic Regulation of Circulation and Adverse Events in Hypertensive Patients during Follow-Up Study

Plethysmographic assessment of vasomotor response in patients with congestive heart failure before and after heart transplantation

Sympathetic vasomotor response is the most important part of the autonomic regulation of circulation, which determines the quality of life. It is disrupted in a number of diseases, particularly in patients with congestive heart failure (CHF). However, experimental evaluation of reflex vasoconstriction is still a non-trivial task due to the limited set of available technologies. The aim of this study is to assess the dynamics of vasomotor response of forearm vessels due to both the deactivation of cardiopulmonary baroreceptors and cold stress using a newly designed imaging plethysmograph (IPG) and compare its performance with classical air plethysmograph (APG). In both vasoconstriction tests, vasomotor response was assessed as a change in the blood flow rate due to venous occlusion compared to that at rest. Both tests were carried out in 45 CHF patients both before and after heart transplantation, as well as in 11 age-matched healthy volunteers. Prior to transplantation, both APG and IPG showed a significant decrease in vasomotor response in CHF patients due to both tests as compared to the control group. After heart transplantation, an increase in vasomotor reactivity was revealed in both vasoconstriction tests. We have found that both plethysmographic techniques provide correlated assessment of changes in the vasomotor response. In addition, we have found that IPG is more resistant to artifacts than APG. The new IPG method has the advantage of measuring blood flow in a contactless manner, making it very promising for experimental evaluation of vasomotor response in clinical conditions.

Cerebral hemodynamic alterations in patients with Covid-19

Background/aim

Coronavirus 2019 disease (Covid-19) was first seen in December 2019 and afterwards it became pandemic. Several systemic involvements have been reported in Covid-19 patients. In this study, it was aimed to investigate the cerebrovascular hemodynamics in patients with Covid-19.

Materials and methods

The sample of this study included 20 patients hospitalized in our clinic diagnosed with Covid-19 via PCR modality and 20 healthy volunteers of similar age and sex. Bilateral middle cerebral arteries were investigated with transcranial Doppler ultrasonography. Basal cerebral blood flow velocities and vasomotor reactivity rates were determined and statistically compared.

Results

When patient and control groups were compared, the mean blood flow velocity was found to be higher in Covid-19 patients than in the healthy volunteers and it was statistically significant (P = 0.00). The mean vasomotor reactivity rates values were found to be lower in the Covid-19 group than the healthy group and was also statistically significant (P = 0.00).

Conclusion

An increase in basal cerebral blood velocity and a decrease in vasomotor reactivity rates in patients with Covid-19 can be considered as an indicator of dysfunction of cerebral hemodynamics in the central nervous system and this can be evaluated as a result of endothelial dysfunction.