Perspectives in Medicine最新文献

Background

The aim of the study was to evaluate correlation of breath holding index (BHI) as functional parameter for intracranial subclinical atherosclerotic changes – we have shown in our previous works and arterial stiffness (AS – functional parameter for extracranial subclinical atherosclerotic changes) in diabetic patients with well and poor controlled glucose blood values in correlation with healthy population.

Patients and methods

We included 60 volunteers divided into 3 aged standardized groups – healthy volunteers, patients with well controlled diabetes and patients with poor controlled diabetes. We excluded individuals with moderate and severe carotid stenosis.

Results

There was decreasing trend in BHI values and increasing trend in AS values in diabetic patients, especially with poor regulated blood glucose values (r = −0.14 and 1.42; p < 0.05).

Conclusion

These results show that decline in BHI as parameter for intracranial microvessel dysfunction is in good correlation with increase of AS as functional parameter of extracranial vascular aging in diabetic patients.

Intravenous tissue plasminogen activator (tPA) remains the only approved, fastest and widely feasible treatment of acute ischemic stroke. Systemic tPA induces recanalization of an occluded vessel, the process thought to lead to neurological recovery. Augmentation of this fibrinolytic activity can be safely achieved with diagnostic ultrasound frequencies and intensities. Ultrasound delivers mechanical pressure waves to thrombi exposing more thrombus surface to circulating drug. International multi-center CLOTBUST trial showed that patients with acute stroke treated with sonothrombolysis (tPA+2 MHz TCD) had more dramatic clinical recovery coupled with arterial recanalization (25% vs 8%) at no increase in the risk of symptomatic intracerebral hemorrhage (sICH). Based on this trial and subsequent phase I–II studies of a novel operator-independent device for delivery of the CLOBUST levels of ultrasound energy, a phase III efficacy trial of sonothrombolysis (named CLOTBUSTER) is being launched in Europe and North America.

Background

Saddle thrombosis is less frequently detected in carotid arteries than in peripheral arterial embolism. The clot and the distal vessel patency have to be promptly recognized in these cases, because if the carotid vessel is open distally, chances may arise for successful emergent surgical procedures to remove the thrombus. At conventional static imaging, mobile floating thrombi may be difficult to differentiate from thrombosis on carotid complicated lesions of atherosclerotic origin. High-resolution ultrasound (US), with its unique capability of real-time imaging, adds fundamental data for interpretation of the findings.

Methods

Carotid ultrasound has been performed in acute stroke patients with high-resolution probes. Real-time clips are analyzed and imaging is presented.

Results

Saddle carotid bifurcation thrombosis of cardiac origin has been identified in 2 patients with acute homolateral ischemic stroke, with prompt successful surgical removal in one case. Moreover, an example of a thrombus attached on the ruptured surface of a complicated atherosclerotic plaque in an acute symptomatic stroke patient that was successfully operated in emergency is presented.

Conclusions

Early high-resolution ultrasound with real-time imaging can easily identify peculiar characteristics of carotid vulnerable diseases in acute stroke phase. Different clinical implications result from the early identification of these different conditions, modifying the therapeutical strategies.

The present study aims to validate the technique of in vitro ultrasonography (US) by comparative analysis of premortem intima–media thickness (IMT), postmortem IMT and average wall thickness. In vivo common carotid artery (CCA) IMT was measured bilaterally in 25 patients at 30 mm proximal from the flow divider. After autopsy in vitro US was performed and postmortem IMT was measured at the same level. Snap frozen arterial specimens were processed for average wall thickness determination and for histology. High degree of correlation was found between in vivo IMT, in vitro IMT and average wall thickness. Our results demonstrate: (1) in vitro US is a reliable and reproducible tool for the examination of autopsied arterial specimens to obtain valuable information about vascular wall properties and to identify the optimal vascular segment for tissue sampling; (2) snap freezing and cryosectioning of in toto excised arterial specimens is recommended for comparative histological–US studies.

Objective

To examine the carotid vessels in stroke and non stroke patients using carotid duplex ultrasonography.

Methods

The author used a cross-sectional approach among 259 patients who were divided into 2 groups: stroke and non-stroke patients. Noninvasive measurements of the intima and media of the common carotid artery were performed with high-resolution ultrasonography to all the patients in both groups.

Results

259 patients, with age ranging from 31 to 75 years old, were divided into the Stroke group (n = 131) and Non-Stroke group (n = 128). The author found abnormal IMT in both groups, with an occurrence of 130 patients in the Stroke group, and 46 in the Non-Stroke group (P < 0.001).

Conclusion

Increased intima and media thickness of the common carotid artery, measured noninvasively by ultrasonography, are associated with cerebrovascular disease manifested as stroke.

Introduction

The ultrasound examination of intracranial venous structures by transcranial color-coded sonography (TCCS) is a validated and standardized application. Similarly some intracranial venous sinuses are known for their relatively low insonation rate, as straight sinus (SRS) and transverse sinus (TS), ranging from 35% to 73%. The relatively high frequency of hypoplasia of TS can partially take account for these data. The aim of this study is to evaluate the feasibility of this approach in a standard TCCS examination, in comparison with magnetic resonance (MR) findings by using the Virtual Navigator system.

Patients and methods

The standardized approach to the TS was a contralateral insonation, starting to the SRS plane and angulating downwards the probe. In this way it is possible to insonate the proximal segment of the contralateral TS. We proposed a new approach with an extreme downwards tilting and a slow opposite angulation of the probe for examining the ispilateral TS. Forty consecutive subjects were chosen among patients who underwent standard TCCS examinations at our lab and had a suitable temporal acoustic window, and a recently performed MR venography. The contralateral TS insonation rate was compared with the ipsilateral one.

Results and discussion

The insonation rate was 61/80 (76.25%) for the contralateral TS and 75/80 (93.75%) for the ipsilateral approach. Two of 5 not detectable TS were aplasic in MR venography and the others were not identified by a poor acoustic window.

Conclusions

The ipsilateral approach could be associated to the contralateral standard study for insonating the TS.

Relation of right-to-left shunt (RLS) with chronic hyperventilation syndrome (CHVS) has not been previously reported. We evaluated the prevalence of RLS in patients with CHVS. Patients with CHVS and 25 healthy controls (CG) were recruited into the study. Vascular RLS was diagnosed using contrast TCD. Of 25 subjects with CHVS, 16 (64%) had RLS vs 3 from CG (12%). TEE confirmed PFO in 10 patients with CHVS (40%) vs 2 from CG (8%). Pulmonary AVM was found in chest CT in 2 patients (10%) with CHVS and none from CG. The prevalence of RLS and PFO in patients with CHVS was significantly higher than in healthy subjects.

Cerebral autoregulation is particularly challenged in acute ischemic stroke. In this review we summarize the data of our previous studies on autoregulation regarding the effect of rtPA on autoregulation after stroke. A pooled analysis of two studies (45 patients) has shown a worsening of the autoregulatory index Mx between an early (first 48 h) and late (days 5–7) measurement. This increase was more pronounced on affected sides than on unaffected sides. Poor ipsilateral Mx was associated with a greater volume of MCA infarction at a late measurement and related to poor clinical outcome. Overall, autoregulatory impairment tends to increase mainly in large infarction and generalize to the contralateral side during the first days after ischemic stroke. As a limitation, transcranial Doppler sonography does not allow to detect focal areas of dysautoregulation in smaller strokes. To better understand the temporal and spatial dynamics of dysautoregulation in acute stroke in relation to the type and size of infarction, new bedside hemodynamic monitoring techniques (like multi-channel near-infrared spectroscopy) are needed.

Carotid stenting is a common procedure for revascularization of carotid artery stenosis. In this study, we evaluated the role of carotid ultrasound post carotid stenting. In a retrospective analysis, we identified 45 patients who received post-stent ultrasound. On routine follow-up we measured a range for peak systolic velocity of 33–150 cm/s and end diastolic velocity 11–52 cm/s. We also identified two cases, where immediate post-stent ultrasound provided critical data that required further intervention, and potentially avoided serious complications.