Disparate cardio-cerebral vascular modulation during standing in multiple system atrophy and Parkinson disease

Cerebral hemodynamic response to generalized anxiety disorder

BACKGROUND

Generalized anxiety disorder (GAD) is the least studied among anxiety disorders. Therefore, we aimed to compare the cervical blood flow velocities using doppler ultrasonography in untreated chronic GAD patients and healthy individuals.

MATERIAL AND METHODS

In this study, thirty-eight GAD patients were enrolled. And thirty-eight healthy volunteers were recruited as control participants. The common carotid artery (CCA), internal carotid artery (ICA), and vertebral artery (VA) of both sides were explored. Also, we trained machine learning models based on cervical arteries characteristics to diagnose GAD patients.

RESULTS

Patients with chronic untreated GAD showed a significant increase in peak systolic velocity (PSV) bilaterally in the CCA and the ICA (P value < 0.05). In GAD patients, the end-diastolic velocity (EDV) of bilateral CCA, VA, and left ICA was significantly decreased. The Resistive Index (RI) showed a significant increase in all patients with GAD. Moreover, the Support Vector Machine (SVM) model showed the best accuracy in identifying anxiety disorder.

CONCLUSION

GAD is associated with hemodynamic alterations of extracranial cervical arteries. With a larger sample size and more generalized data, it is possible to make a robust machine learning-based model for GAD diagnosis.

Impaired Cerebral Autoregulation in Alzheimer's Disease: A Transcranial Doppler Study

BACKGROUND

Vasculature changes have been observed in Alzheimer's disease (AD). AD-related vascular pathology might impair cerebral autoregulation (CA).

OBJECTIVE

This study was designed to evaluate CA of AD patients by using transcranial doppler (TCD).

METHODS

A total of 61 participants were included in the study, including 31 AD patients and 30 controls. The trend curves of cerebral blood flow velocities (CBFV), pulsatility index, and resistance index were obtained using TCD during supine-to-standing posture changes. CA was measured by the changes of CBFV curves during supine-to-standing test.

RESULTS

There were two spikes named X spike and W spike that appeared in the CBFV curve when the subjects stood abruptly. The slope of the X spike descending branch, the slope of the W spike ascending branch, and the angle between X and W spikes (α angle), showed significant differences between the experimental and control groups (2.34±0.99 versus 3.15±1.61 cm/s2, p = 0.021; 2.31±0.81 versus 3.38±1.18 cm/s2, p < 0.001; and 52.71±20.26 versus 41.4±12.87 degrees, p = 0.012, respectively). ROC analysis showed that AUCαangle is 0.664 (p = 0.028) and that AUCSAB and AUCadjustedSAB are 0.775 and 0.738, respectively (both p < 0.001).

CONCLUSIONS

Our study demonstrated that supine-to-standing TCD test is a valuable tool for the evaluation of CA in AD patients. Impaired CA in AD patients manifested as decreased efficiency of changes in the CBFV curve. Neurovascular units were involved in the pathogenesis of AD.

Characteristics of cardio-Cerebrovascular modulation in patients with generalized anxiety disorder: an observational study

BACKGROUND

Generalized anxiety disorder (GAD) has been shown in previous studies to display abnormal cerebral blood flow velocity (CBFV); however, the characteristics of cardio-cerebrovascular modulation are unknown. We aimed to analyze cardio-cerebrovascular modulation using parameters from a supine-to-standing test.

METHODS

There are 2 parts to this study; in Part 1, 125 participants with Hamilton Anxiety scale scores ≥14 were enrolled, and 33 age- and sex-matched medically and psychiatrically healthy volunteers were recruited as control participants. Patients were divided by score into mild, moderate, and severe anxiety groups. The cardio-cerebrovascular modulation using the parameters of dynamic changes of CBFV and heart rate in response to an orthostatic challenge were investigated. In Part 2, we followed up the severe GAD patients for 6 months and repeated the supine-to-standing test, and severe GAD patients were divided into recovery and non-recovery groups.

RESULTS

In part 1, the GAD group displayed more marked CBFV and heart rate changes than the healthy group, but there was no difference in the CBFV and heart rate changes from the supine to upright position in mild, moderate, and severe anxiety groups. In part 2, The recovery group demonstrated significant improvement in changes in the CBFV and heart rate values from the supine to the upright position after treatment compared with before treatment. In the non-recovery group, the CBFV and heart rate changes were significantly higher than the healthy group regardless of treatment.

CONCLUSIONS

Cardio-cerebrovascular modulation is compromised in patients with GAD, however, this impairment can be restored to normal after the disappearance of anxiety.

Supine-to-standing transcranial Doppler test in patients with multiple system atrophy

BACKGROUND

Supine-to-standing test, a transcranial Doppler (TCD) based technique, has been recently developed to evaluate cardiovascular dysautonomia. We explored the value of supine-to-standing TCD test in predicting the course of multiple system atrophy (MSA) with orthostatic hypotension (OH).

METHODS

By monitoring the signals of middle cerebral artery during supine-to-standing posture changes, the trend curves of cerebral blood flow velocities, pulsatility index and resistance index were obtained from 38 MSA patients with OH and 31 healthy subjects. The correlation between TCD findings and the clinical outcome of the patients, which was determined by follow-up structured phone interview, was analyzed. Adverse outcome was defined if a patient died, was in bed-ridden state or had recurrent syncope (>1 per month).

RESULTS

Two characteristic TCD findings were revealed in the MSA patients but not in the controls, i.e. a blunted cerebral blood flow velocity rebound after standing and/or sustained higher pulsatility index upon standing than supine baseline. Structured phone interview was completed in 31 of the 38 patients (mean follow-up time, 20 ± 11 months). While no subject had recurrent syncope before enrollment, 12 patients developed an adverse outcome during follow-up. The coexistence of two characteristic TCD findings predicted adverse outcomes with positive predictive value 66.7% and negative predictive value 87.5%.

CONCLUSIONS

Supine-to-standing TCD test is valuable in predicting the course of MSA with OH at early stage. We hypothesize baroreflex failure effects and paradoxical cerebral vasoconstriction in response to OH may account for the TCD findings in MSA patients.

Compromised cerebrovascular modulation in chronic anxiety: evidence from cerebral blood flow velocity measured by transcranial Doppler sonography

OBJECTIVE

Cerebral autoregulation (CA) is the mechanism by which constant cerebral blood flow is maintained despite changes in cerebral perfusion pressure. CA can be evaluated by dynamic monitoring of cerebral blood flow velocity (CBFV) with transcranial Doppler sonography (TCD). The present study aimed to explore CA in chronic anxiety.

METHODS

Subjects with Hamilton anxiety scale scores ≥14 were enrolled and the dynamic changes of CBFV in response to an orthostatic challenge were investigated using TCD.

RESULTS

In both the anxious and the healthy subjects, the mean CBFV was significantly lower in the upright position than when supine. However, the CBFV changes from supine to upright differed between the anxious and the healthy groups. Anxious subjects showed more pronounced decreases in CBFV with abrupt standing.

CONCLUSION

Our results indicate that cerebrovascular modulation is compromised in chronic anxiety; anxious subjects have some insufficiency in maintaining cerebral perfusion after postural change. Given the fact that anxiety and impaired CA are associated with cardiovascular disease, early ascertainment of compromised cerebrovascular modulation using TCD might suggest interventional therapies in the anxious population, and improve the primary prevention of cardiovascular disease.