Management of abdominal aortic prosthetic graft and endograft infections. A multidisciplinary update.

Abdominal aortic graft infections (AGIs) occur in 1-5% of aortic prosthetic placements. It can result in limb amputation, pseudo-aneurysm formation, septic emboli, aorto-enteric fistulae, septic shock and death. The most frequently involved pathogens are methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci, followed by Enterobacteriaceae and uncommon bacteria. In case of gut involvement the presence of fungi has to be considered. Computed tomography angiography is actually the gold standard diagnostic imaging but magnetic resonance is a valid alternative. Nuclear medicine imaging is commonly used to improve sensitivity and specificity. Signs and symptoms are often aspecific and blood cultures can be negative, requiring alternative ways to detect the microorganism responsible for infection, such as 16S rRNA gene sequencing and molecular rapid diagnostic tests. Curative surgical intervention is the first choice approach, with in-situ reconstruction providing by far the best outcome and xenopericardial bovine patch as a promising option. For patients unable to undergo major surgery, the outcome of conservative approach remains uncertain but usually provides for life-long suppressive therapy. However, in selected cases an attempt of stopping antibiotic treatment after 3-6 months can be done. Given the difficulty in their management, we performed a review of AGIs, in order to raise awareness on clinical presentation, current available diagnostic tools, prophylaxis, surgical and anti-infective treatment of AGIs.

Value of percent change in tumoral volume measured at T2 -weighted and diffusion-weighted MRI to identify responders after neoadjuvant chemoradiation therapy in patients with locally advanced rectal carcinoma.

PURPOSE: To evaluate the percent change in tumoral volume measured at T2 -weighted magnetic resonance imaging (T2 WMRI) and diffusion-weighted (DWI) as a method to identify responders after chemo- and radiation therapy (CRT) in patients with locally advanced rectal carcinoma. MATERIALS AND METHODS: Forty-five consecutive patients (mean age ± SD: 72 years ± 9.7; male/female = 24/21) with locally advanced rectal carcinoma underwent CRT followed by surgery. Each patient underwent T2 WMRI and DWI at 1.5T before and 6 weeks after the completion of CRT. The percent change in tumoral volume before and 6 weeks after CRT was compared in patients classified as responders and nonresponders according to rectal cancer regression grade. RESULTS: Twenty-five patients were classified as responders with either partial (n = 20) or complete response (n = 5), while 20 patients were classified as nonresponders due to stable disease (n = 18) or disease progression (n = 2). Responders vs. nonresponders differed in the percent change of tumoral volume at T2 WMRI (-67% ± 26% vs. -29% ± 26%; P < 0.05) and DWI images (-72% ± 24% vs. -33% ± 28%; P < 0.05) with a cutoff ≤ -70% for T2 WMRI (sensitivity = 69%, 95% confidence interval [CI]: 48-85%; specificity = 100%, 95% CI 81-100%) and ≤66% for DWI (sensitivity = 73%, 95% CI: 52-88%; specificity = 100%, 95% CI 81-100%). CONCLUSION: The percent change in tumoral volume at T2 WMRI and DWI images can differentiate responders from nonresponders in patients with locally advanced rectal carcinoma after neoadjuvant CRT. J. Magn. Reson. Imaging 2016;44:1415-1424.

Bilateral spontaneous internal carotid artery dissection with both early and very late recanalization: A case report.

Spontaneous bilateral internal carotid artery dissection has frequently been described in the literature as a cause of stroke. In more than half of the patients with internal carotid artery dissection, recanalization occurs early after the event and is unusual later than 6 months after onset of the dissection. We describe a patient with ischemic stroke due to left internal carotid artery occlusion in the extracranial segment. The patient was treated with anticoagulants and early vessel recanalization did not occur. Ten months later, he developed contralateral internal carotid occlusion in the intracranial tract, which was followed by early complete recanalization. Anticoagulation therapy was continued and, 16 months after the initial event, the left internal carotid artery unexpectedly also reopened.

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.

Noninvasive imaging of carotid arteries in stroke: emerging value of real-time high-resolution sonography in carotid occlusion due to cardiac embolism.

OBJECTIVE: Comprehension of the pathophysiologic characteristics of atherosclerosis has focused its attention on the study of dynamic and metabolic processes involving the vessel wall as possible causes of stroke. When compared with conventional radiologic techniques, sonography has the main advantage of being a real-time imaging modality. We report 2 acute stroke cases in which carotid sonography showed some dynamic features that could not be identified with computed tomography (CT) and magnetic resonance angiography (MRA). METHODS: Carotid sonography with high-resolution probes (9-14 MHz) was compared with CT and MRA findings showing carotid axis occlusion in 2 patients with acute stroke. RESULTS: In case 1, the internal carotid artery occlusion observed on CT and MRA was interpreted as a dissection on a clinical basis, but sonography showed a mobile embolus originating from the heart in the internal carotid artery. In case 2, the occlusion of the whole carotid axis observed on CT and MRA was instead related to a heart-originating embolus floating in the common carotid artery. CONCLUSIONS: The evaluation of dynamic aspects of atherosclerosis is fundamental to understanding the pathophysiologic characteristics of stroke. Sonography is fundamental in carotid artery imaging for its possibility of showing dynamic processes that could be misdiagnosed with "static" imaging. The correct identification of the pathophysiologic characteristics of stroke in these cases could have led to different diagnostic and therapeutic algorithms.

Cerebral vasomotor reactivity is reduced in patients with erectile dysfunction.

BACKGROUND: 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/CO(2)) 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/CO(2) 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 (>or=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 (>or=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.

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.

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

OBJECTIVE: 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. METHODS: We assessed CCA IMT, the CCA RI, and the presence of carotid plaques in 1655 consecutive patients. Demographic features and vascular risk factors were collected. RESULTS: A positive linear relationship between mean IMT and age was observed (R(2) = 0.27; P < .001). In the multiple stepwise regression model, the presence of ICA plaques and vascular risk factors were all independently associated with higher IMT. When considering IMT values for left and right sides separately, there was an independent relationship between CCA IMT and the lateralized percentage of ICA stenosis (right IMT-right ICA percentage, R(2) = 0.10; P < .0001; left IMT-left ICA percentage, R(2) = 0.16; P < .0001) and the CCA RI, even after correcting for age and vascular risk factors. CONCLUSIONS: Risk factors for atherosclerosis and the percentage of ICA stenosis were independently associated with higher IMT values and an increase in the RI. The synergic action of risk factors may cause further deterioration of mechanical forces independent of carotid atherosclerosis.

Stroke beyond the first hours: the role of monitoring.

It is now recognized that a specialized multidisciplinary team, focusing on the care of stroke patients, leads to lower mortality and better outcomes. The positive effect of stroke units in regard to the outcome of stroke patients seems to be related to the careful monitoring of clinical parameters and clinical emergencies. The monitoring of physiological parameters in the acute phase of stroke can be considered an important management tool that can improve significantly the quality of care provided. It allows timely detection and correction of complications and consequently has a beneficial effect on outcome.