Differential Influence of Carotid Stenosis and White Matter Disease on Motor and Cognitive Activation.

BACKGROUND: Cognitive and motor performance can be supported, especially in older subjects, by different types of brain activations, which can be accurately studied by functional magnetic resonance imaging (fMRI). Vascular risk factors (VRFs) are extremely important in the development of cognitive impairment, but few studies have focused on the fMRI cortical activation characteristics of healthy subjects with and without silent cerebrovascular disease including white matter hyperintensities (WMH) and carotid stenosis (CS) performing cognitive tasks. METHODS: Thirty-five volunteers with and without asymptomatic unilateral carotid stenosis above 70% and variable degrees of WMH underwent performance of a simple motor and cognitive task during an fMRI session. RESULTS: While the performance of the motor task resulted in a cortical activation dependent of age but not of WMH and carotid stenosis, performance of the cognitive task was accompanied by a significantly increased activation independently correlated with age, presence of WMH as well as of carotid stenosis. CONCLUSIONS: in this study, cognitive domains regulating attention and working memory appear to be activated with a pattern influenced by the presence of carotid stenosis as well as by white matter hyperintensities. The impairment of these cognitive abilities is of high relevance in Alzheimer's disease pathology. The fMRI pattern shown in patients with asymptomatic but significant carotid stenosis might be related to chronic cerebrovascular hypoperfusion, a critical pathophysiological mechanisms in AD. In these patients, carotid endoarterectomy should be considered also for AD prevention and might be recommended.

Emergency and early carotid endarterectomy in patients with acute ischemic stroke selected with a predefined protocol. A prospective pilot study.

AIM: The appropriateness of early carotid endarterectomy (CEA) in patients with acute ischemic stroke is still unsettled. The aim of this study was to verify the safety and feasibility of early CEA in a consecutive series of patients with acute ischemic stroke observed in an emergency Department Stroke Unit. METHODS: During a 24-month study, out of 756 patients with acute ischemic stroke 33 (4.4%) were scheduled for early CEA. Endarterectomy procedures were distinguished according to the time between the onset of stroke and operation as emergency (within 8 hours), early CEA (1-18 days). Patients with impaired consciousness or an infarct larger than 2.5 cm on computed tomographic (CT) or magnetic resonance (MR) scans or both were excluded from surgery. All patients underwent spiral CT, echo-color-Doppler (ECD) sonography, transcranial Doppler (TCD) sonography and, when necessary, MR angiography within 6 hours of admission. No patient underwent conventional angiography. Most patients were operated on under cervical block (CB) anesthesia; general anesthesia (GA) was used only for those with an unstable neurological deficit. Selective shunting was used on the basis of intra-operative transcranial Doppler in patients under GA and the onset or worsening of neurological deficit under CB anesthesia. RESULTS: Of the 6 patients operated on within a median 6 hours after the onset of stroke, 1 (16.5%) had a fatal hemorrhagic transformation of the infarct, while the remaining 5 (83.5%) stopped fluctuating or progressing and had a favourable neurological outcome. Of the 16 patients operated on within a median 36 hours and of the 11 patients operated on within 7 days, none deteriorated after operation. CONCLUSION: Emergency CEA is feasible for acute ischaemic stroke provided that strict selection criteria are applied and the door-to-surgery interval is kept short (within 8 hours). Early CEA for secondary prevention is feasible and safe, confirming that a delayed operation is in most cases unwarranted. Large randomized trials are warranted before implementing emergent and early CEA in routine clinical practice.

Somatosensory evoked potentials versus locoregional anaesthesia in the monitoring of cerebral function during carotid artery surgery: preliminary results of a prospective study.

OBJECTIVE: to relate changes in somatosensory-evoked potentials (SEPs) with onset of neurological deficits in patients having carotid endarterectomy (CEA) under locoregional anaesthesia. METHODS: a prospective study of 50 consecutive patients. RESULTS: SEPs yielded an accuracy of 98%, specificity 100%, and sensitivity 89%. In all concordant cases the onset of a neurological deficit in awake patients corresponded to a 30--40% reduction in amplitude of N20-P25 waveforms. After shunting, the N20-P25 took 2--3 min to return to normal. CONCLUSIONS: SEPs are associated with a 2% false negative rate. Their threshold for detecting cerebral ischaemia is lower than the currently reported value for patients under general anaesthesia. The time needed for evoked potentials (2--3 min) to return to normal after shunting limits their usefulness in verifying effective shunting.

[Diagnostic methods and therapeutic options in vasculogenic impotence]. / Metodologia diagnostica e possibilità terapeutiche nell'impotenza vasculogenica.

Until a few years ago, the main cause of men's genital impotence was reputed to be psychogenic. On the other hand, the development of diagnostic techniques has been in aid in isolating the most frequent cause of impotence among the organic forms, and in particular those of vascular origin. The authors herein examine the diagnostic methods of vasculogenic impotence and evaluate the therapeutic options in relation to the various causes identified.

Intraoperative transcranial Doppler sonography monitoring during carotid surgery under locoregional anaesthesia.

OBJECTIVES: Studies comparing transcranial Doppler ultrasonography (TCD) with other intraoperative monitoring techniques for detecting clamping ischaemia during carotid endarterectomy under general anaesthesia suggest that a reduction of > two-thirds in the mean middle cerebral artery velocity (mMCAv) or a reduction of > 0.4 in the preclamping mMCAv: clamping mMCAv ratio warrants cerebral protection. Our aim was to study the relationship between mMCAvs and clamping ischaemia during carotid endarterectomy in awake patients. MATERIALS AND METHODS: In a consecutive series of 57 patients undergoing carotid endarterectomy under locoregional anaesthesia 51 were monitored by intraoperative TCD, continuous EEG, and neurologic awake testing. RESULTS: Five of the 51 (9.8%) patients had transient clamping ischaemia, which carotid shunting reversed. TCD showed that these five patients had significant lower mean mMCAvs than the other 46 patients, who had no deficits (1.8 +/- 1.1 cm/s vs. 26.2 +/- 8.5, p = 0.0003). Current TCD criteria indicated that four other patients (7.8%) should have been shunted. All four had significantly higher clamping mMCAvs than the five shunted patients (11.5 +/- 1.9 vs. 1.8 +/- 1.1, p = 0.0012). CONCLUSIONS: Intraoperative TCD detected cerebral ischaemia and yielded no false-negative. An mMCAv of 10 cm/s or less may indicate the risk of clamping ischaemia better than the higher threshold currently proposed. This would avoid unnecessary shunting due to false-positives.

For how long should carotid endarterectomy surveillance be continued?

Early restenosis represent the most important and more common failure after carotid endarterectomy. For this reason, after its first description made in 1976 by Stoney and String, it raised general interest among vascular surgeons. In spite of the efforts to clear the causes of this phenomenon, none of the numerous papers published in the literature has defined a specific cause determining restenosis. Nevertheless, at present, this hyperplastic response of the arterial wall to trauma after operation is generally considered benign because it is rarely responsible for new neurological symptoms or early internal carotid artery occlusion. This unanimous conviction has been achieved after years of instrumental and clinical postoperative follow-up performed all over the world. At the same time and probably for these reasons, recently, a new discussion has begun about the usefulness and cost-effectiveness of prolonged Duplex scanning postoperative surveillance of the endarterectomized carotid arteries. This new question raised our curiosity in verifying the validity of this new approach, so we reviewed accurately our laboratory follow-up registry and the data regarding onset, evolution and clinical outcome of early restenosis. These data associated with a meticulous review of the experience of other authors convinced us that the patients operated on, need, in most cases, a short even aggressive period of careful follow-up (generally the first six months).(ABSTRACT TRUNCATED AT 250 WORDS)

Post-carotid endarterectomy hyperperfusion syndrome: preliminary observations for identifying at risk patients by transcranial Doppler sonography and the acetazolamide test.

Patients at risk of hyperperfusion syndrome after carotid endarterectomy are often severely hypertensive and have a high grade internal carotid artery stenosis with disordered autoregulation due to a loss of reserve capacity (RC). Cerebral RC can be studied by sophisticated and expensive technical devices (SPECT, PET). Recently it has been demonstrated that the transcranial Doppler (TCD) and acetazolamide provocation test can be used to assess RC. From September 1991 to January 1992, 36 patients were studied by the TCD and acetazolamide test prior to carotid endarterectomy to identify patients at high risk of the hyperperfusion syndrome. Preoperatively, the patients were studied by TCD at rest and after vasolidation with acetazolamide 1 g intravenously (i.v.). Mean blood flow velocity on the middle cerebral artery (MCAv) was recorded for the following 20 min at 5 min intervals. MCAv at rest was 49 +/- 17 cm/s. After acetzaolamide infusion in 33 patients (92%), the mean MCAv was 62 +/- 19 cm/s with an increase of 19 +/- 13 cm/s (normal RC). In three patients (8%), the mean MCAv was 43 +/- 22 cm/s with a decrease of -6 +/- 3 cm/s with respect to base values (reduction of RC). (t = 3.30; p = 0.0022). All these patients were hypertensive (BP > 180/100 mmHg) and had a carotid artery stenosis > 90%. Postoperatively, the three patients with reduction of RC complained of homolateral headache. TCD showed a mean MCAv of 67 +/- 17 cm/s, an increase compared to the preoperative rest values of 17 +/- 8 cm/s, the 33 patients with normal RC showed a mean change in MCAv -2 +/- 12 cm/s.(ABSTRACT TRUNCATED AT 250 WORDS)