Transcranial Doppler studies in Type 2 diabetes mellitus: A systematic review

Cerebral Haemodynamic Changes in Type 2 Diabetes Mellitus Following a Three-Month Yoga Intervention: A Randomized Controlled Trial

Background and purpose Cerebral haemodynamics and cognitive performance may be adversely affected in type 2 diabetes mellitus (T2DM). Previous studies reported reduced cerebral blood flow (CBF) and altered cerebrovascular reactivity (CVR) in T2DM. Yoga, an ancient holistic health approach, is known to be beneficial for T2DM. We hypothesized that yoga practice may alter CBF and the flow resistance in the middle cerebral artery (MCA) and improve cognition in T2DM. Our secondary objective was to explore the relationship between changes in cerebral haemodynamics and cognition in T2DM. Materials and methods Participants were randomly allotted into the yoga and control groups based on the eligibility criteria. One hour of yoga intervention specific to type 2 diabetes was provided to the yoga group for three months, while conventional treatment was provided to the control group. A transcranial Doppler was used to evaluate longitudinal changes in cerebral haemodynamics in MCA. A Corsi block tapping test was used to assess visio-spatial working memory. Results There were 75 participants recruited, of whom 38 participated in yoga and 37 participated in a control group. Both intention to treat and per protocol analysis showed significant results. At day 90, intention-to-treat analysis showed significant changes in CBF velocities (mean difference -10.85%, 95% CI (-13.26, -6.15), p<0.001), cerebral vasodilatory reserve (mean difference -0.23%, 95% CI (-0.43, -0.03), p=0.02) and cognition (mean difference -12.13%, 95% CI (-17.48, -6.78), p≤0.001). There was no between-group effect. Also, the correlation between the CBF and cognition did not show any significant results. Conclusion The three-month yoga intervention was associated with an improvement in cerebral hemodynamics. The study also revealed an improvement in visio-spatial working memory among patients with T2DM. The study did not show any correlation between the improvement in cerebral haemodynamics and working memory. We recommend larger and longer studies on yoga intervention for T2DM patients to evaluate whether such benefits are sustained and improve their quality of life.

Effect of 23 % low-sodium salt applied to Chinese modified DASH diet on cerebrovascular function in patients with hypertension and type 2 diabetes: a pilot study

Introduction

Aim: to investigate the effects of low sodium formula salt combined with the Chinese Modified Dietary Approaches to Stop Hypertension (DASH) diet on cerebrovascular function in patients with hypertension and type 2 diabetes. Methods: an eight-week single-arm trial was conducted in 66 patients with hypertension and type 2 diabetes to investigate effects of low sodium formula salt (potassium chloride 56 %, sodium chloride 23 %, 5 g/day) combined with Chinese Modified DASH diet on cerebrovascular function (measured by transcranial Doppler sonography), indicators of chronic diseases (blood pressure, blood glucose and blood lipids) and urinary excretion. The above indicators were performed before and after intervention. Results: fifty-nine subjects completed the study. Peak systolic velocity, mean flow velocity, end-diastolic velocity, pulsatility index and resistance index of internal cerebral artery and vertebral artery decreased significantly (p < 0.05); pulsatility index and resistance index of anterior cerebral artery and middle cerebral artery decreased significantly (p < 0.05); and end-diastolic velocity and pulsatility index of basilar artery decreased significantly (p < 0.05). Systolic blood pressure, diastolic blood pressure, fasting blood glucose and postprandial blood glucose decreased significantly (p < 0.001; p < 0.001; p < 0.001; p < 0.001). Blood pressure and blood glucose control rates increased significantly (p < 0.001). Conclusions: based on the study, 23 % low-sodium formula combined with CM-DASH diet pattern can improve cerebrovascular function in community patients with hypertension complicated with diabetes and has a good short-term benefit of blood pressure and glucose control.

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 of Obesity and Overweight with Cervical Vascular Function Among Healthy Populations

PURPOSE

To study the effects of obesity and overweight on carotid vascular function among healthy populations by carotid ultrasound (CAU) and transcranial Doppler (TCD).

MATERIALS AND METHODS

Basic clinical characteristics, CAU and TCD parameters were collected from recruited healthy individuals. Firstly, all participants were divided into three groups: normal, overweight and obese. Then, the variability of basic clinical characteristics and lipids between the three groups was calculated. Subsequently, CAU and TCD parameters were compared between the three groups. Finally, the correlation between body mass index (BMI) and neck vascular function was analyzed.

RESULTS

A total of 613 healthy participants were included, of whom 241 were normal, 264 were overweight, and 108 were obese. Overweight and obesity significantly decreased systolic, diastolic and mean flow velocities in the basilar, vertebral and internal carotid arteries, but had no effect on pulsatility index. In addition, BMI was significantly negatively correlated with systolic, diastolic, and mean flow velocities in the basilar, vertebral, and internal carotid arteries, and remained correlated after adjusting for other factors. There was no effect of overweight and obesity on carotid plaques.

CONCLUSION

Our study revealed that overweight and obesity decreased carotid vascular flow velocity and showed a decreasing trend in vascular flow velocity with increasing BMI. Overweight and obesity appear to have no effect on carotid plaques.