Multidisciplinary treatment of posterior circulation ischemia

Impairment of attention network function in posterior circulation ischemia-evidence from the Attention Network Test

Objective

This study aimed to investigate the effect of posterior circulation ischemia (PCI) on attention network function and to determine whether PCI is holistic or selective attention network deficit and which attention network is affected.

Methods

Thirty-six PCI patients aged 30 to 75 were assessed using the Attention Network Test and the Mini-Mental State Examination (MMSE). There were no significant differences in age, sex, and education between PCI group and the control group (n = 32). All data were statistically analyzed by SPSS 23.0 software.

Result

There were no significant difference in the MMSE scores between the two groups. Compared with the control group, the PCI group had significantly shorter response time for alerting and orienting network. The executive control network response time was significantly longer in PCI group than in the control group. The overall mean response time was also significantly longer in PCI group than in normal control group. There was no significant difference in mean accuracy between the two groups.

Conclusion

The alerting, orienting, and executive control networks were significantly less efficient in PCI group than in the control group (P < 0.01). This indicates impaired attention network in PCI patients. Since transient nerve seizures caused by vertebrobasilar ischemia may precede posterior circulation stroke, early assessment of cognitive function in patients with PCI is particularly important, and ANT is an excellent tool for this assessment.

Update on diagnosis and differential diagnosis of vestibular migraine

BACKGROUND

Vestibular migraine (VM) is considered the most common cause of spontaneous episodic vertigo and the second most common cause of vertigo. However, without a biomarker or a complete understanding of the pathophysiology, VM remains underrecognized and underdiagnosed. Therefore, definite diagnostic criteria are urgently needed. Meanwhile, VM should be clearly differentiated from other similar diseases. This paper may help clinicians improve the diagnostic rate of VM and reduce the rate of misdiagnosis. A PubMed search was performed using the following terms: vestibular migraine, migraine-associated vertigo/dizziness, migraine-related vertigo, migraine-related vestibulopathy, benign recurrent vertigo, vertiginous migraine, migraine, headache, vertigo, dizziness, and diagnosis. This paper also summarizes the diagnostic criteria and differential diagnoses of VM. The diagnosis of VM is based on the symptoms, degree, frequency, and duration of the vestibular episodes, a history of migraine, and the temporal association of migraine symptoms with vestibular episodes in at least 50% of cases, while ruling out what may be due to other reasons. In addition to vestibular symptoms and migraine, transient auditory symptoms, nausea, vomiting, and susceptibility to motion sickness may also be associated with VM. Thus, VM should be differentiated from other diseases such as Meniere's disease, benign paroxysmal positional vertigo, migraine with brainstem aura, vestibular neuritis, posterior circulation ischemia, multiple lacunar infarction, vestibular paroxysmia, motion sickness, and episodic ataxia type 2.

CONCLUSION

Only if the diagnostic criteria of VM and differential diagnosis can be mastered clearly, we can make a definite diagnosis and treat patients properly.

Low bone mineral density is associated with intracranial posterior circulation atherosclerosis in women

Low bone mineral density (BMD) is associated with carotid atherosclerosis and the incidence of stroke. However, there are no data on the association of BMD with intracranial atherosclerosis. The study population consisted of 357 participants who underwent dual energy x-ray absorptiometric scanning of the lumbar spine and brain 3D time of flight magnetic resonance angiography as part of their voluntary health checks. The basilar, middle cerebral, intracranial internal carotid and intracranial vertebral arteries were evaluated. Low BMD was defined as a T-score of less than -1. All analyses were stratified by sex and intracranial atherosclerosis location. One hundred seventy-six women (53 years; 66.9% postmenopausal; 33.5% low BMD; 60.2% intracranial atherosclerosis in the anterior circulation (AC); 60.2% intracranial atherosclerosis in the posterior circulation (PC)) and 181 men (51 years; 28.7% low BMD; 61.9% intracranial atherosclerosis in the AC; 55.8% intracranial atherosclerosis in the PC) were included. In women, low BMD was significantly associated with intracranial atherosclerosis in the PC with the odds ratio of 2.57 (95% confidence interval 1.11-5.99). However, intracranial atherosclerosis in the AC was not associated with BMD in women. In men, there were no significant associations between BMD and intracranial atherosclerosis. In conclusion, this study shows that low BMD is associated with subclinical intracranial PC atherosclerosis in women but not in men.

Preliminary evidence supporting the safety of drug-eluting stents in neurovascular disease

OBJECTIVE

Restenosis is a significant complication of stent placement. With coronary revascularization, drug-eluting stents have significantly decreased the incidence of in-stent stenosis and, therefore, the morbidity of the procedure. Restenosis is potentially a significant problem for neurovascular disease. We therefore report our institutional experience on the use of drug-eluting stents for the management of cerebrovascular insufficiency.

METHODS

Over a period of 2 years, 19 patients underwent extra- and intracranial drug-eluting stent placement for intra- and extracranial atherosclerotic disease. There were 12 males and seven females aged between 36 and 83 years old (mean 65). Thirteen heparin, three rapamycin, and three taxus-coated stents were placed. There were five intracranial internal carotid arteries, two intracranial vertebral arteries, three mid-basilar, six of vertebral artery origin and three middle cerebral artery stents utilized. No complications occurred.

RESULTS

There was one case of re-stenosis associated with recurrent symptoms requiring repeat drug eluting stent placement. No other patients have developed new or recurrent neurological symptoms. Five of six vertebral artery origin stents were placed with distal protection to prevent embolic complications.

CONCLUSION

Intracranial and extracranial drug-eluting stent placement appears to be a safe alternative to the medical management of atherosclerotic disease of the vertebrobasilar and carotid systems. However, further randomized studies are needed to examine the effectiveness and safety of this procedure.

Distal superficial temporal artery to proximal posterior cerebral artery bypass by posterior oblique transzygomatic subtemporal approach

This article investigates the possibility for the distal superficial temporal artery (STA) to proximal posterior cerebral artery (PCA) direct bypass by subtemporal oblique posterior transzygomatic approach. Five adult cadaveric specimens were dissected. Cadeveric dissection protocol was approved by the Research Ethics Committee. A preauricular vertical skin incision was made, the trunk of STA was identified, and bifurcation, frontal, and parietal branches of the STA were followed distally. Posterior zygomatic arch osteotomy and microcraniotomy were then performed, and the dura was opened. The temporal lobe was retracted, interpeduncular and ambient cisterns were opened, and the P2 segment of the PCA was exposed. Parietal branch of STA and P2 segment of the PCA was anastomosed. The average length of the transected STA from the bifurcation and the zygomatic arch were 47.3 ± 2.1 mm and 71.4 ± 2.3 mm, respectively. The mean calibers of the parietal and frontal branch of the STA at this distance were 1.6 ± 0.1 and 1.4 ± 0.2, respectively. The mean diameter of the P2 was 2.1 ± 0.2 mm. Because of the calibers of the parietal branch of the STA and proximal PCA are over 1.5 mm and 2.0 mm, respectively, this direct end-to-side bypass technique may be a reasonable alternative in suitable cases.

Enhanced external counterpulsation and traction therapy ameliorates rotational vertebral artery flow insufficiency resulting from cervical spondylosis

STUDY DESIGN

Clinical trial of patients with rotational vertebrobasilar insufficiency (VBI) resulting from cervical spondylosis.

OBJECTIVE

To investigate the effectiveness of enhanced external counterpulsation (EECP) and traction therapy for these patients.

SUMMARY OF BACKGROUND DATA

EECP would reduce arterial stiffness and vascular resistance, and increase regional blood flow of vertebral arteries, thus may ameliorate symptoms in these patients.

METHODS

One hundred sixty-three patients who were clinically suspected rotational VBI caused by cervical spondylosis were enrolled in this study. They were randomly allocated into 3 groups: EECP + traction, EECP, and traction group. All patients and 50 healthy volunteers received transcranial color Doppler examination of the vertebral artery and basilar artery in both a neutral cervical spine position and a rotational position.

RESULTS

Within 3 days after treatment, 47 (84%) patients in EECP + traction group, 32 (61%) patients in EECP group, and 8 (15%) patients in traction group achieved successful outcomes, while at 3 months' follow-up, 45 (80%) patients in EECP + traction group, 34 (64%) in EECP group, and 3 (6%) in traction group achieved successful outcomes. With head rotation, the percentage of reduction of blood flow velocities of the vertebrobasilar artery (VBA) in patients was much greater than that of the healthy volunteers (P < 0.01). After treatment, rotational blood flow velocity reduction percentage of VBA in each treatment group was much lower than that of each group before treatment. EECP + traction group experienced the greatest decrease of rotational blood flow velocity reduction percentage of VBA, while EECP group experienced second greatest.

CONCLUSION

EECP and traction therapy can relieve the symptoms of rotational VBI, improve the rotational reduction of vertebrobasilar blood flow, and reduce the increased arterial impedance.

Percutaneous intervention for posterior fossa ischemia. A single center experience and review of the literature

OBJECTIVES

The purpose of our study was to evaluate the results of endovascular treatment of symptomatic vertebro-basilar insufficiency (VBI) unresponsive to medical therapy.

METHODS

Cardiac patients regularly followed in our cardiology clinic with symptoms suggestive of posterior fossa ischemia diagnosed by the attending cardiologist, had diagnostic or suspicious findings of vertebral artery stenosis on ultrasound evaluation, with reversed vertebral flow on Doppler examination. These patients were referred for selective vertebral and subclavian artery angiography. All patients (17 men, 11 women; mean age of 64 years, range 54-87) had critical lesions (> 70% stenosis) in the vertebral or pre-vertebral subclavian arteries or both. After confirmation of the severity of the lesions and feasibility for revascularization, all these patients underwent percutaneous intervention and stent placement. All patients were followed-up through clinic visits for a mean of 14.2 months, (range 3.5-24.3).

RESULTS

In our 28 patients that were treated, 25 vertebral and 10 subclavian stents were placed. Success (< 20% residual diameter stenosis, without stroke or death) was achieved in 27 patients (96%). One patient undergoing intervention for an ostial subtotal occlusion of the left subclavian artery, developed a minor posterior fossa transient ischemic attack. At follow-up, 25 patients (89%) were alive and 22 (88%) of those had no further neurologic complaints. Three (11%) patients that had vertebral artery stents, died during follow-up from cardiac complications, unrelated to the neurovascular intervention. One patient (3.5%) had recurrent symptoms with in-stent restenosis at 6 months with successful balloon angioplasty and resolution of symptoms. The two other patients with persistent symptoms (only dizziness) had no evidence of restenosis and underwent further work-up that has not clarified the etiology.

CONCLUSIONS

Posterior fossa ischemia is an under-diagnosed condition that occurs with relative frequency in cardiac patients. Awareness of this condition and adequate non-invasive testing permits identification of these patients. Endovascular treatment using coronary wires and stents including drug eluting stents, seems to be the treatment of choice for vertebral artery revascularization due to the high technical success rate, low complication rate, and long-term durability.

Percutaneous vertebral artery intervention: a necessary tool in every interventional cardiologist armamentarium

OBJECTIVES

The purpose of this study was to evaluate the results of endovascular treatment of symptomatic vertebrobasilar insufficiency unresponsive to medical therapy.

METHODS

Twenty-eight patients who were regularly followed up in our cardiology clinic with symptoms suggestive of posterior fossa ischemia and with diagnostic or suspicious findings on ultrasound evaluation were evaluated with selective vertebral and subclavian artery angiography. All patients (17 men, 11 women; mean age, 64 years; range, 54-87) had critical lesions (>70% stenosis) in the vertebral or subclavian arteries or both. Those lesions that were considered severe enough to explain the reported symptomatology underwent percutaneous intervention and stent placement. All patients were followed up through clinic visits for a mean of 14.2 months (range, 3.5-24.3).

RESULTS

In the 28 patients treated, 25 vertebral and 10 subclavian stents were placed. Success (<20% residual diameter stenosis, without stroke or death) was achieved in 27 patients (96%). One patient who had been undergoing intervention for a subtotal occlusion of the left subclavian artery developed a posterior fossa transient ischemic attack. At follow-up, 25 patients (89%) were alive, and 22 (88%) of those had no further neurological complaints. Three (11%) patients died during follow-up from cardiac complications. One (3.5%) patient had recurrent symptoms with in-stent restenosis at 6 months with successful balloon angioplasty and resolution of symptoms.

CONCLUSIONS

Posterior fossa ischemia is an underdiagnosed condition that occurs with relative frequency in the usual patient population that interventional cardiologists attend to. Endovascular treatment using coronary wires and stents including drug-eluting stents is the treatment of choice for vertebral artery revascularization due to its high technical success rate, low complication rate, and long-term durability.

Symptomatic intracerebral hematomas in posterior circulation stroke patients anticoagulated with heparin

BACKGROUND

A lot of clinicians use heparin in patients with posterior circulation stroke. Frequency and risk factors of symptomatic intracerebral hematoma (ICH) in posterior circulation infarct patients anticoagulated with unfractionated heparin are not known.

METHODS

To determine the incidence and the risk factors of the heparin-related ICH in posterior circulation infarct patients, we retrospectively reviewed the clinical features of 37 patients who had acute posterior circulation infarct and received intravenous heparin after they underwent brain computed tomographic scans and diffusion-weighted imaging (DWI). Follow-up brain scans were obtained at any time if clinical symptoms worsened. Volumes of acute posterior circulation infarction were calculated on DWI.

RESULTS

Of 37 patients, four (10.8%) developed symptomatic ICH during heparin infusion. The location of ICH was cerebellum in all the hemorrhagic worsening patients. We found that the size of an acute infarction calculated on DWI is the risk factor of symptomatic ICH during intravenous heparin therapy in patients with posterior circulation infarct.

CONCLUSIONS

Until a large prospective study is performed, it may be prudent to avoid heparin infusion in patients with large posterior circulation infarct documented on DWI.

Color Doppler analysis of vertebral arteries: correlative study with angiographic data

OBJECTIVE

Color Doppler ultrasonography is the most widespread diagnostic procedure in obstructive disease of the arteries supplying the brain. To our knowledge, there are only a few correlative color Doppler ultrasonographic and angiographic studies of the vertebral arteries, especially in patients who have flow-restrictive stenosis at the carotid bifurcation. The main purpose of this prospective study was to evaluate diameter, flow volume, and time-averaged mean velocities of angiographically verified normal vertebral arteries without collateral flow. The second purpose was to try to establish a threshold value for the flow volume of the vertebral artery.

METHODS

One hundred twenty patients referred for carotid angiography with a normal vertebrobasilar system and with no patent posterior communicating arteries were investigated with color Doppler ultrasonography. Luminal diameter, time-averaged mean velocity, peak systolic velocity, and flow volume values were calculated for each patient. The parameters were compared between sexes, in different age groups, in patients with carotid stenosis of 50% or less and greater than 50%, and in patients who had clinical signs of vertebrobasilar insufficiency versus those who had not.

RESULTS

We have found no significant difference in evaluated parameters with the degree of associated carotid stenosis or vertebrobasilar insufficiency. Diameter and flow volume values on the left side were higher than on the right side.

CONCLUSIONS

We found similar flow volume values of vertebral arteries in both sexes and both groups of patients with carotid stenosis of 50% or less and greater than 50%. All parameters did not differ in patients with stenosis of 50% or less and greater than 50% and in patients with and without clinical signs of vertebrobasilar insufficiency.