Prognosis of high-risk patients with nonoperated symptomatic extracranial carotid tight stenosis

Endovascular stenting for vertebral artery stenosis

OBJECTIVES

The aim of this study was to demonstrate the safety and long-term durability of catheter-based therapy for symptomatic vertebral artery stenosis (VAS).

BACKGROUND

Symptomatic VAS carries with it a 5-year 30% to 35% risk of stroke. The 2-year mortality approaches 30% for medically managed strokes involving the posterior circulation. Surgical bypass is rarely performed, due to high morbidity and mortality. Endovascular revascularization with primary stenting offers an attractive treatment option for these patients.

METHODS

One-hundred five consecutive symptomatic patients (112 arteries, 71% male) underwent stent placement for extracranial (91%) and intracranial (9%) VAS from 1995 to 2006. Fifty-seven patients (54%) had bilateral VAS, 71 patients (68%) had concomitant carotid disease, and 43 patients (41%) had a prior stroke.

RESULTS

Procedural and clinical success was achieved in 105 (100%) and 95 (90.5%) patients, respectively. One-year follow-up was obtained in 87 (82.9%) patients, of which 69 patients (79.3%) remained symptom-free. At 1 year, 6 patients (5.7%) had died and 5 patients (5%) had a posterior circulation stroke. Target vessel revascularization occurred in 7.4% at 1 year. At a median follow-up of 29.1 months (interquartile range 12.8 to 50.9 months), 13.1% underwent target vessel revascularization, 71.4% were alive, and 70.5% remained symptom-free.

CONCLUSIONS

In experienced hands, stenting for symptomatic VAS can be accomplished with a very high success rate (100%), with few periprocedural complications, and is associated with durable symptom resolution in the majority (approximately 80%) of patients. We conclude that endovascular stenting of vertebral artery atherosclerotic disease is safe and effective compared with surgical controls and should be considered first-line therapy for this disease.

Carotid plaque surface irregularity predicts ischemic stroke: the northern Manhattan study

BACKGROUND AND PURPOSE

There is scant population-based evidence regarding extracranial carotid plaque surface irregularity and ischemic stroke. Using a prospective cohort design, we evaluated the association of carotid plaque surface irregularity and the risk of ischemic stroke in a multiethnic population.

METHODS

High-resolution B-mode ultrasound of the carotid arteries was performed in 1939 stroke-free subjects (mean age 69+/-10.0 years; 59% women; 53% Hispanic, 25% black, 22% white). Plaque was defined as a focal protrusion 50% greater than the surrounding area and localized along the extracranial carotid tree (internal carotid artery/bifurcation vs common carotid artery). Plaque surface was categorized as regular or irregular. Cox proportional hazard models were used to assess the association of surface characteristics and the risk of ischemic stroke.

RESULTS

Among 1939 total subjects, carotid plaque was visualized in 56.3% (1 plaque: 21.6%, >1 plaque: 34.7%, irregular plaque: 5.5%). During a mean follow up of 6.2 years after ultrasound examination, 69 ischemic strokes occurred. Unadjusted cumulative 5-year risks of ischemic stroke were: 1.3%, 3.0%, and 8.5% for no plaque, regular plaque, and irregular plaque, respectively. After adjusting for demographics, traditional vascular risk factors, degree of stenosis, and plaque thickness, presence of irregular plaque (vs no plaque) was independently associated with ischemic stroke (Hazard ratio, 3.1; 95% CI, 1.1 to 8.5).

CONCLUSIONS

The presence of irregular carotid plaque independently predicted ischemic stroke in a multiethnic cohort. Plaque surface irregularities assessed by B-mode ultrasonography may help identify intermediate- to high-risk individuals beyond their vascular risk assessed by the presence of traditional risk factors.

Preoperative construction of an extracranial arterial shunt for resection of an aortic arch aneurysm with occluded left carotid artery

A 68-year-old man with aortic arch aneurysm was referred to our department. Preoperative carotid echography and magnetic resonance angiography revealed occlusion of the left internal carotid artery. Single-photon emission computed tomography scanning indicated that cerebral blood flow was decreased and reactivity to acetazolamide was reduced in the left temporal lobe. A successful superficial temporal artery-middle cerebral artery anastomosis was first made by neurosurgeons. A postoperative single-photon emission computed tomography scan showed that cerebral blood flow and reactivity to acetazolamide were remarkably improved. Two months after the anastomosis, the aortic arch aneurysm was successfully repaired.

Hemodynamic role of the circle of Willis in stenoses of internal carotid arteries. An analytical solution of a linear model

A mathematical model of blood flow through the circle of Willis was developed, within a linear framework. Comprehensive analytical solutions, including a remarkably small number of parameters, were derived in the cases of obstructive lesions of extracranial carotid arteries. The influence of these lesions and the role of anterior and posterior communicating arteries on the blood pressure at the entry of the cerebral territories were quantified and analyzed emphasizing that the responses of the system of Willis to obstructive carotid lesions are extremely varied, depending on the communicating artery anatomy. Comparison with numerical results obtained by using a non-linear model showed no physiologically significant differences. Such a model might be an essential tool for an accurate assessment of the cerebral hemodynamics in carotid diseases.

Deriving clinical prediction rules from stroke outcome research

BACKGROUND AND PURPOSE

Our purpose was to determine whether clinical prediction rules could be derived from current stroke outcome research.

SUMMARY OF REPORT

We reviewed 92 articles on stroke outcome research to determine their suitability for implementation as a clinical prediction rule. Methodological problems in many of these studies made implementation of their results as a clinical prediction rule difficult.

CONCLUSIONS

Implementation of stroke outcome research as clinical prediction rules would be facilitated by description of patient population demographics; precise definitions of predictor and outcome measures; stratification of patients by stroke mechanism; use of adequate patient sample sizes; and description of the mathematical methods used, including coding schemes, cutpoints, beta coefficients, constant terms, and a priori probabilities.

Carotid stenosis in lacunar stroke

The prevalence of extracranial carotid stenosis in patients with a clinical syndrome of lacunar stroke has not been extensively studied using noninvasive methods. We performed carotid duplex sonography on 168 patients referred to the neurosonology laboratory with a diagnosis of ischemic stroke. Strokes were independently classified as lacunar or nonlacunar hemispheric infarction without knowledge of the ultrasound results. We excluded patients with infarcts that were clearly vertebrobasilar, presumed to be cardioembolic, or had occurred greater than 1 year earlier, and patients for whom classification of the nature and location of the event was not possible. Fifty-five patients had lacunar and 54 had nonlacunar stroke. No differences in age, sex, distribution, or prevalence of hypertension, diabetes, prior ischemia, or Hispanic surname existed between the two groups. Tobacco use was more frequent in the nonlacunar group (p less than 0.01). The prevalence of important extracranial carotid stenosis (greater than or equal to 50% diameter reduction) in the lacunar stroke group was 13% (seven of 55) in the ipsilateral and 4% (two of 55) in the contralateral carotid artery. Of the 54 patients with nonlacunar hemispheric stroke, 41% (22) had ipsilateral (p less than 0.01) and 26% (14) had contralateral (p less than 0.01) carotid stenosis. This study suggests that important carotid stenosis is infrequent among patients presenting with a clinical syndrome of lacunar stroke. These data impact on decisions regarding cerebrovascular work-up in such patients.

Prolonged hypoperfusion and early stroke after transient ischemic attack

Many patients suffer a stroke early after a transient ischemic attack, but the reason why is often unclear. We studied 12 patients with less than 75% stenosis of the internal carotid artery and a single hemispheric transient ischemic attack lasting less than 1 hour who had a normal neurologic examination 3-13 hours later and a normal computed tomogram 24-36 hours later. Single-photon emission computed tomography using technetium-99m HM-PAO less than or equal to 50 hours after the attack showed no abnormality in eight patients, but in the other four there was an area with 30-50% reduction in perfusion ipsilateral to the transient ischemic attack. Three of these four patients developed an ipsilateral infarct 3-7 days later, but none of the eight patients with normal single-photon emission computed tomograms had a stroke during the following weeks. No difference in therapy, risk factors, severity of internal carotid artery disease, or timing of the technetium-99m study could explain these findings. We suggest that some transient ischemic attacks, though clinically identical to others, may be associated with persisting focal hypoperfusion, which predisposes to early stroke.