Functional assessment of high-grade ICA stenosis with duplex ultrasound and transcranial Doppler

Cerebrovascular Reserve Capacity as a Predictor of Postoperative Delirium: A Pilot Study

Introduction: Postoperative delirium is a common complication after cardiac surgery with cardiopulmonary bypass (CPB). Compromised regulation of the cerebral circulation may be a predisposing factor for delirium. However, the potential relationship between cerebrovascular reserve capacity and delirium is unknown. The aim of this study was to investigate if impaired cerebrovascular reserve capacity was associated with postoperative delirium. Methods: Forty-two patients scheduled for cardiac surgery with CPB were recruited consecutively. All patients underwent preoperative transcranial Doppler (TCD) ultrasound with calculation of breath-hold index (BHI). BHI < 0.69 indicated impaired cerebrovascular reserve capacity. In addition, patients were examined with preoperative neuropsychological tests such as MMSE (Mini Mental State Examination) and AQT (A Quick Test of cognitive speed). Postoperative delirium was assessed using Nursing Delirium Screening Scale (Nu-DESC) in which a score of ≥2 was considered as delirium. Results: Six patients (14%) scored high for postoperative delirium and all demonstrated impaired preoperative cerebrovascular reserve capacity. Median (25th-75th percentile) BHI in patients with postoperative delirium was significantly lower compared to the non-delirium group [0.26 (-0.08-0.44) vs. 0.83 (0.57-1.08), p = 0.002]. Preoperative MMSE score was lower in patients who developed postoperative delirium (median, 25th-75th percentile; 26.5, 24-28 vs. 28.5, 27-29, p = 0.024). Similarly, patients with postoperative delirium also displayed a slower performance during the preoperative cognitive speed test AQT color and form (mean ± SD; 85.8 s ± 19.3 vs. 69.6 s ± 15.8, p = 0.043). Conclusion: The present findings suggest that an extended preoperative ultrasound protocol with TCD evaluation of cerebrovascular reserve capacity and neuropsychological tests may be valuable in identifying patients with increased risk of developing delirium after cardiac surgery.

Diameter-based measurements of the degree of carotid artery stenosis using ultrasonography

Flow velocity measurement by duplex ultrasonography (DUS) is widely accepted as a preoperative method for grading carotid stenoses. Diameter-based grading is used for angiographic methods, but so far the experience is limited regarding diameter-based grading using DUS. In 101 cases with different degrees of carotid stenoses, we compared diameter- and velocity-based grading using DUS and evaluated variability and reproducibility for diameter measurements in 38 of the stenoses. In 18% of the cases, suboptimal image quality with calcifications and acoustic shadowing precluded diameter measurements. In the remaining 83 cases, the agreement between velocity-based and diameter-based grading for distinction between significant and non-significant stenosis was 69% with a kappa value of 0.40. Repeated measurements of diameters showed a coefficient of variation of 10% and intraclass coefficients of correlation of 0.9. We conclude that diameter measurement with DUS can be performed with high reproducibility in most patients with carotid stenosis. These measurements can then be used for calculations of the degree of stenosis, to supplement velocity-based grading. The moderate agreement between diameter-based and flow velocity-based grading cannot easily be explained. Discrepancies probably constitute a mixture of methodological errors and hemodynamic factors and need further evaluation.

The effect of traditional Tibetan guozhuang dance on vascular health in elderly individuals living at high altitudes

To evaluate the effect of dance on vascular-related factors and cerebral hemodynamics in elderly individuals in Qinghai-Tibetan plateau regions (mean altitude ≥2,300 m). Thirty elderly individuals, who practiced traditional Tibetan Guozhuang dance or did not, were enrolled, respectively. Serum PGC-1α, HCY, FSTL-1, VEGF and HIF-1α were measured by ELISA assays. Carotid artery stenosis and plaque, IMT, extracranial internal carotid artery stenosis and cerebral arteriosclerosis were evaluated using CUS and TCD. Body weight, BMI, heart rate, systolic pressure, and diastolic pressure, serum BGS, TC, LDL, HIF-1α, VEGF, and HCY in the dance group were significantly lower than the no-dance group. FSTL-1 levels, SO₂ and SO₂/heart rate ratio in the dance group were significantly higher than the no-dance group. Incidence of extracranial internal carotid artery stenosis, carotid stenosis and plaque in the dance group was significantly lower than the no-dance group. IMT was a significant positive correlation between PGC-1α and HCY in the no-dance group. Elderly individuals who regularly practiced Tibetan dance had improved blood vessel functionality and cerebral hemodynamic at high altitudes.

Evaluation of cerebrovascular reserve capacity in symptomatic and asymptomatic internal carotid stenosis with transcranial Doppler

Cerebrovascular reserve capacity (CVRC) is a hemodynamic parameter indicating the brain's capacity to overcome ischemia. Transcranial Doppler (TCD) is a useful device to measure CVRC, with high availability and low cost. The aim of the study is to investigate asymptomatic patients with affected CVRC, who could benefit from CEA. One hundred and forty five consecutive patients (60 symptomatic and 65 asymptomatic), with internal carotid artery (ICA) stenosis >70 % and 20 healthy individuals without internal carotid stenosis underwent TCD-inhalation CO(2) tests in order to measure the CVRC in both hemispheres of each patient. CVRC between asymptomatic and symptomatic patients were significantly different in the 95 % confidence interval (CI) as well as the mean CVRC value in contralateral carotid artery. The correlation between CVRC in the carotid artery with stenosis and the existence of symptoms is significant at the 0.01 level. Additionally, symptoms and CVRC of the contralateral carotid artery are also significant at the 0.05 level and CVRC values in asymptomatic patients and the control group at the 0.01 level. None of the covariant factors, except the age, are significantly correlated with CRVC. CVRC could be an early mark-index to evaluate the risk of stroke in this group of patients and to design their therapeutic approach.

Feasibility of assessment of conjunctival microvascular hemodynamics in unilateral ischemic stroke

Since the internal carotid artery supplies blood to both the eye and the brain, ocular microvascular hemodynamics can be altered due to ischemic stroke. The purpose of the current study was to establish the feasibility of conjunctival microcirculation imaging for detection of inter-ocular differences in microvascular hemodynamics in subjects with unilateral ischemic stroke. Conjunctival microcirculation imaging was performed in both eyes of 15 healthy control subjects and 12 subjects following unilateral ischemic stroke. Diameter and axial blood velocity were measured in multiple conjunctival venules of each eye. A two-way repeated measures analysis of variance was performed to determine the effects of stroke (control vs. stroke) and side of stroke (ipsilateral vs. contralateral) on conjunctival diameter and axial blood velocity. There was no significant main effect of stroke on conjunctival diameter (P=0.7) or conjunctival axial blood velocity (P=0.9). There was no significant main effect of side of stroke on conjunctival diameter (P=0.8), but there was a significant main effect of side of stroke on conjunctival axial blood velocity (P=0.02). There was a significant interaction effect between stroke and side of stroke (P=0.04), indicating that conjunctival axial blood velocity was lower in ipsilateral eyes than in contralateral eyes of stroke subjects. Conjunctival axial blood velocity and internal carotid artery blood velocity were correlated in stroke subjects (r=0.75, P=0.01, N=10). Conjunctival microcirculation imaging is a feasible method to detect inter-ocular differences in microvascular hemodynamics in subjects with unilateral ischemic stroke.

Usefulness of transcranial Doppler ultrasound in evaluating cervical-cranial collateral circulations

Transcranial Doppler (TCD) ultrasound is a noninvasive, safe and cost-effective bedside test for evaluating cerebrovascular circulation in real time. It has been rapidly evolving from a simple noninvasive diagnostic tool to an imaging model with a broad spectrum of clinical applications. TCD can show the spectral flow waveforms, blood flow direction, velocities and intensity in the intracerebral vessels, adding physiologic information to other imaging models. TCD can also detect collateral channels through the anterior communicating artery, posterior communicating arteries, reversed ophthalmic artery, leptomeningeal collaterals, reversed basilar artery and reversed vertebral artery caused by hemodynamically significant carotid or intracranial stenosis. This article gives a brief overview of its use in evaluation of collateral circulation in carotid and intracranial steno-occlusive disease.

Comparison between visual assessment of dopaminergic degeneration pattern and semi-quantitative ratio calculations in patients with Parkinson's disease and Atypical Parkinsonian syndromes using DaTSCAN® SPECT

OBJECTIVE

To verify if (123)I-FP-CIT, DaTSCAN(®) can differentiate early stages of Parkinson's disease (PD) as well as patients with Atypical Parkinsonian syndromes (APS) from manifest Parkinson's disease.

METHODS

128 consecutive patients were investigated with (123)I-FP-CIT SPECT during a 4-year period. All patients were diagnosed according to the established consensus criteria for diagnosis of PD (n = 53) and APS (n = 19). Remaining patients were grouped early PD (before onset of L-DOPA medication), (n = 20), vascular PD (n = 6), and non-PD syndromes (n = 30) and SWEDD (n = 1). SPECT images were analyzed visually according to a predefined ranking scale of dopaminergic nerve cell degeneration, distinguishing a posterior-anterior degeneration pattern (egg shape) from a more global and severe degeneration pattern (burst striatum). Striatum uptake ratios were quantitatively analyzed with the 3D software, EXINI.

RESULTS

In the group of APS patients, the burst striatum pattern was most frequent and found in 61 % (11/18 patients). In PD patients, the egg shape pattern was dominating, especially in early PD where it was present in 95 % (19/20 patients). The positive predictive value for the egg shape pattern to diagnose PD was 92 % in this material (APS and all PD patients) and the specificity 90 % for the burst striatum pattern to exclude APS. The uptake ratios were reduced in both PD and APS patients and closely related to the image ranking.

CONCLUSION

In this study, we found that in more than half of the patients it was possible to differentiate between PD and APS by visual interpretation only. Similar results were obtained using semi-quantitative uptake ratios. Combining visual assessment with uptake ratios did not add to the discriminating power of DaTSCAN(®) SPECT in this material.