Maria Chiara Ricciardi

Contrast Carotid Ultrasound for the Detection of Unstable Plaques with Neoangiogenesis: A Pilot Study

OBJECTIVES To evaluate whether contrast ultrasonography can be used to distinguish asymptomatic from symptomatic carotid plaques and provide insight into underlying pathophysiological differences. DESIGN Contrast carotid ultrasound was performed in both symptomatic and asymptomatic patients referred for carotid endarterectomy. MATERIALS AND METHODS Of 77 consecutive patients referred for carotid artery evaluation, 64 underwent carotid endarterectomy for asymptomatic cerebrovascular disease and 9 underwent urgent surgery for acute neurological deficits with hemiparesis. The endarterectomy specimens were assessed immunohistologically. RESULTS In all 9 patients undergoing urgent surgery, contrast ultrasonography showed the accumulation of diffuse microbubble contrast at the base of the carotid plaque. This pattern was observed only in 1/64 of the patients undergoing surgery for asymptomatic carotid disease. Immunohistologically staining of the endarterectomy specimens showed that the area of microbubble contrast at the base of the symptomatic plaques was associated with an increased number of small diameter (20-30 microm) microvessels staining for vascular endothelial growth factor (VEGF). CONCLUSIONS Contrast carotid ultrasonography may allow the identification of microvessels with neoangiogenesis at the base of carotid plaques, and differentiate symptomatic from asymptomatic plaques.

Detection of Carotid Adventitial Vasa Vasorum and Plaque Vascularization With Ultrasound Cadence Contrast Pulse Sequencing Technique and Echo-Contrast Agent

Background and Purpose— Adventitial vasa vasorum and plaque vascularization have been established as predictors of unstable atheromasic lesions in cerebro- and cardiovascular patients. Ultrasound contrast agents provide reliable information on tissue perfusion and microcirculation. We used contrast ultrasound duplex scanning to identify carotid plaque vascularization. Methods— Contrast carotid duplex scanning was performed in 23 patients with plaques of different degree of stenosis and echogenicity. Results— Plaque vascularization was detected in the fibrous and fibro-fatty tissue and not observed in the calcific nor in the necrotic and hemorrhagic tissue. Constantly, a small vessel was observed under ulcerations. Conclusions— Carotid contrast ultrasound imaging appears to be an emerging technique for identifying plaque angiogenesis. Further studies are needed to clarify the role of plaque angiogenesis for assessing cerebrovascular risk and to monitor effects of therapies aimed to plaque remodelling.

Cerebrovascular Reactivity in Degenerative and Vascular Dementia: A Transcranial Doppler Study

Background: An impairment of cerebral microvessels is reported both in normal ageing and in senescence-associated processes, as well as in Alzheimer’s disease (AD) and vascular dementia (VaD). The aim of this study was to explore cerebral hemodynamics by transcranial Doppler in VaD and AD, compared with age-matched control subjects. Methods: Transcranial Doppler was investigated in all patients in the basal condition. Cerebral vasoreactivity to hyper- and hypocapnia was evaluated with CO2 mixture inhalation followed by hyperventilation. Results: We studied 60 AD and 58 VaD patients and 62 nondemented controls. Both AD and VaD subjects showed lower flow velocities (FV) and higher pulsatility indices (PI) as compared with controls. Lower total vasomotor reactivity and lower response to hypercapnia were observed in the AD and VaD groups as compared with controls. AD and VaD patients did not show significant differences in FV, PI values or cerebral vasoreactivity. Conclusions: Reduced FV and increased PI with a significant vasoreactivity reduction in VaD and AD patients are indicators of impairment of cerebral microvasculature circulation in both diseases. The identification of vascular function impairment in all kinds of dementia could be of help in identifying patients who would thus benefit more from specific therapeutic approaches.

Monitoring After the Acute Stage of Stroke A Prospective Study

Background and Purposes— In the early stage of stroke, the occurrence of neurologic and medical complications is associated with clinical deterioration. Previous studies were focused on the first week after stroke onset. The aim of this study was to evaluate the impact of complications on clinical outcome in patients with stroke in the early subacute stage. Methods— We prospectively evaluated the influence on the outcome of complications feasible (MC) and not feasible for monitoring (NMC) in all patients with stroke admitted consecutively in our subacute stroke unit. Patients were divided into three classes according to stroke severity evaluated by the National Institutes of Health Stroke Scale score. A change in the National Institutes of Health Stroke Scale score group from admission to discharge was considered clinically significant. Results— We included 261 patients. Sixty percent of patients had complications (105 MC, 118 NMC). Hyperthermia (OR=14.12; 95% CI: 6.01 to 33.20), urinary infections (OR=4.92; 95% CI: 2.19 to 11.04), hypertension (OR=2.86; 95% CI: 1.21 to 6.76), hypoxia (OR=15.75; 95% CI: 6.73 to 36.84), and neuroradiologic damage progression (OR=58.31; 95% CI, 19.48 to 174.55) were associated with a change to a more severe class at discharge and with a higher risk of mortality. Conclusions— A high percentage of patients can develop both MC and NMC during this subacute stage of stroke. The occurrence of complications influences outcome and raises the question about the need for a prolonged stay in a dedicated ward for patients with stroke.

Common carotid artery intima-media thickness determinants in a population study.

Common carotid artery (CCA) intima‐media thickness (IMT) is considered an atherosclerosis risk marker. Thickening of the intima‐media complex is accelerated by vascular risk factors, in particular, by age and elevated blood pressure. Nonetheless, it also reflects intimal hyperplasia and intimal fibrocellular hypertrophy provoked by nonatherosclerotic mechanisms such as tensile wall stress. The aims of our study were to investigate the relationship between CCA IMT and the presence of vascular risk factors and to correlate CCA IMT with the degree of distal internal carotid artery (ICA) stenosis and the proximal CCA resistive index (RI), representative of wall stress.

Extracranial and Intracranial Sonographic Findings in Vertebral Artery Diseases

Objective. The aim of this review is to illustrate the sonographic features that can be detected in vertebral artery (VA) diseases. Methods. We conducted a review of sonographic findings in VA diseases. Results. Various VA diseases are described, and sonographic techniques and features are discussed. Conclusions. Posterior circulation vascular imaging can be performed by means of various neuroimaging techniques. Intra‐arterial angiography remains the reference standard. The use of this technique has become even more widespread since it has become possible to perform endovascular procedures; it is, however, an invasive procedure that is associated with a not irrelevant level of risk. Computed tomographic angiography and magnetic resonance angiography with and without contrast agents have been proposed as less invasive alternatives, although these techniques can only be performed in the radiology unit and may not be readily available in daily clinical management. Sonography, which combines an extracranial and intracranial evaluation, is highly suited to the assessment of the vertebrobasilar system on account of its widespread availability and its unique capacity to study real‐time hemodynamics. Furthermore, new sonographic applications and sonographic contrast agents have improved the sensitivity and specificity of this technique with regard to diagnostic accuracy for the posterior circulation.

Cerebral vasomotor reactivity is reduced in patients with erectile dysfunction.

Backgrounds: Erectile dysfunction (ED) is not only evidence of diffuse atherosclerosis but also an index of early endothelial damage. We investigated cerebrovascular reactivity, expression of early arterial damage, in patients with isolated ED (ED+) and controls (ED–). Materials and Methods: Fifteen ED+ and 15 ED– subjects, matched for age (ED+: 58±6, ED–: 59 ± 4 years) and vascular risk factors, were submitted to carotid duplex ultrasound and transcranial Doppler. Cerebrovascular reactivity was assessed on both middle cerebral arteries simultaneously calculating (a) the total vasomotor range (VMR) measured after breath holding and hyperventilation and (b) the rate of change (VMR/CO2) after breath holding. Results: Carotid Duplex scanning showed a light carotid stenosis only in 3 (2 in the ED+ and 1 in the ED– group). No differences were observed in intima-media thickness between ED+ and ED–. Slightly slower mean middle cerebral artery flow velocities were observed in ED+ with respect to ED–. ED+ patients showed a reduced VMR (p < 0.001) and a slower VMR/CO2 rate of change (p < 0.001) compared to ED–. Conclusions: The reduced reactivity in patients with isolated ED may represent a marker of early cerebral vasomotor dysfunction due to subclinical endothelial damage.

Sonographic Carotid Plaque Morphologic Characteristics and Vascular Risk Factors : Results From a Population Study

Objective. The role of vascular risk factors in atherosclerosis development is well established, whereas risk factors involved in determining plaque vulnerability are still a matter of debate. We investigated the vascular risk factor distribution in patients with carotid plaques. Methods. We consecutively assessed sonographic plaque morphologic characteristics, the degree of stenosis, and the common carotid artery intima‐media thickness (IMT) in 1655 patients. Demographic data, a documented history of symptomatic cerebrovascular disease (CVD), and the presence of vascular risk factors were collected. According to literature, heterogeneous hypoechoic plaques with an irregular surface or ulcerations and those with a severe degree of stenosis (≥70%) have been considered “complex” plaques at “major” risk of stroke; homogeneous hyperechoic plaques with smooth surface lesions have been considered “simple” plaques at minor risk. Results. Univariate analysis showed that all vascular risk factors were associated with the presence of carotid atherosclerotic lesions. Multiple logistic regression showed an independent association of hypertension and diabetes with complex plaques, which also had a thicker IMT. A history of CVD was observed more frequently in complex plaques, which had a higher stenosis percentage even after patients with a severe degree of stenosis (≥70%) and indications for carotid surgery were excluded. Conclusions. Hypertension and diabetes are related to a thicker IMT and more severe complex plaques, which may reflect the instability of atherosclerotic process. Because two‐thirds of the patients with complex plaques were asymptomatic for CVD, this raises the importance of surveillance sonography to monitor plaque evolution for prevention of symptomatic CVD.

Functional MRI, Drugs, and Poststroke Recovery

Stroke is the first cause of disability in industrialized countries. Thus, understanding the mechanisms of poststroke recovery appears to be crucial in improving motor performance and reducing disability in stroke patients. Strategies through which brain restores lost functions after ischemic lesions are numerous. The mechanisms underlying poststroke recovery, known as cerebral plasticity, are so far hypothetical. However, functional magnetic resonance imaging (fMRI) studies recently have provided new insights in to stroke recovery. This article sketches out the mechanisms that are thought to underly recovery and focuses on fMRI experimental studies that have investigated the influence of a number of drugs on functional recovery. Functional MRI is a valuable tool in understanding functional recovery and may help to disclose new therapeutical approaches.

Transcranial Doppler for Brain Death in Infants: The Role of the Fontanelles

Objective: Transcranial Doppler (TCD) is a sensitive technique for circulatory arrest diagnosis in brain death when patterns such as reverberant flow and short systolic spikes are observed. In infants, the nonossified fontanelles compensate for intracranial hypertension. We describe TCD patterns in infants with brain death, different from adults, with the hemodynamic modifications induced by anterior fontanelle compression. Method: TCD was performed in 2 infants with diagnosed brain death admitted to the neonatal intensive care unit. Results: TCD showed a large peak ‘reverberant’ flow, with a high peak systolic velocity and a consistent retrograde component, away from the brain. Compression of the anterior fontanelle induced, at first, a reduction in systolic flow with the subsequent appearance of the characteristic short systolic spikes. Upon compression removal, a brief increase in the systolic flow was observed before the prompt reappearance of the reverberant flow. Conclusion: TCD for brain death diagnosis should be done cautiously in infants. In these cases, reverberating flow may be indicative of circulatory arrest even if with a large peak and with a high peak systolic velocity. Heavy fontanelle compression may reproduce the classical adult TCD patterns of brain death, thus supporting the diagnosis of cerebral circulatory arrest.