Intracranial vertebral artery dissection resulting in fatal subarachnoid hemorrhage: clinical and histopathological investigations from a medicolegal perspective

De Novo Vertebral Artery Dissecting Aneurysm after Parent Artery Occlusion of the Contralateral Vertebral Artery

After treatment of unilateral vertebral artery dissecting aneurysm (VADA), de novo VADA rarely occurs on the contralateral side. In this article, we report a case of subarachnoid hemorrhage (SAH) due to de novo VADA in the contralateral vertebral artery (VA) 3 years after parent artery occlusion of unilateral VADA, with a review of the literature. A 47-year-old woman was admitted to our hospital complaining of headache and impaired consciousness. Head computed tomography showed SAH, and three-dimensional computed tomography angiography showed a fusiform aneurysm in the left VA. We performed an emergency parent artery occlusion. Three years and 3 months after the initial treatment, the patient presented to our hospital with complaints of headache and neck pain. Magnetic resonance imaging revealed SAH, and magnetic resonance angiography revealed de novo VADA in the right VA. We performed a stent-assisted coil embolization. The patient had a good postoperative course and was discharged with a modified Rankin scale score of 0. Long-term follow-up is necessary in patients with VADA because contralateral de novo VADA can develop even several years after the initial treatment.

Efficacy and predicting factors of multimodal treatment for ruptured intracranial vertebral artery dissecting aneurysms

We aimed to investigate the efficacy of our multimodal strategies and propose a treatment algorithm for ruptured vertebral artery dissecting aneurysms (VADAs). This study included 41 patients treated at a single institution between 2015 and 2022. The treatment modalities were justified based on the collateral circulation and aneurysm location related to the posterior inferior cerebellar artery (PICA). Treatment outcomes and complications of each treatment group were analyzed. The association between the collateral blood flow and the postoperative vertebrobasilar ischemia (VBI) was also investigated. There were 17 post-PICA, 10 PICA-involved, 7 pre-PICA, and 7 non-PICA types. Reconstruction techniques included flow diversion devices (n = 11) and stent-assisted coiling (n = 3). Deconstruction techniques included coil trapping (n=17) and microsurgical parent artery occlusion with (n = 8) or without PICA revascularization (n = 2). Five (18.5%) of the deconstruction group had postoperative VBI. Overall favorable outcomes in both groups were observed in 70.7% of patients with a mean follow-up time of 21.5 months. Poor World Federation of Neurosurgical Societies grade (IV-V) was identified as a predictor of unfavorable outcomes (p = 0.003). In addition, the VA4/BA4 ratio > 0.22, the presence of collateral blood flow from the posterior communicating artery (PcomA), and a contralateral VA diameter > 2.5 mm were associated with a lower risk of postoperative VBI. In summary, the proposed strategic treatment in this study is pragmatic, yielding satisfactory results where a deconstructive technique should be used with caution, particularly when there is a flow mismatch or the absence of collateral PcomA in the vertebrobasilar circulation.

Reconstructive embolization for contralateral vertebral artery dissecting aneurysm that developed after internal trapping of ruptured vertebral artery dissection: A case report and literature review

Background:

It is not well-known that contralateral vertebral artery dissecting aneurysms (VADA) may be newly revealed after parental artery occlusion for unilateral VADA. However, the optimal treatment strategies and perioperative management have not been established. In this report, we present the case of a patient who required reconstructive embolization in the subacute stage for contralateral VADA developed after endovascular internal trapping of the ruptured VADA.

Case Description:

A 61-year-old man developed subsequent disturbance of consciousness. Head CT showed a diffuse and symmetrical SAH. 3DCT revealed a fusiform aneurysm of the left intracranial vertebral artery with bleb formation. We performed emergency endovascular parent artery occlusion of the left vertebral artery. A digital subtraction angiography on postoperative day 16 showed continued occlusion of the left VA, and a fusiform aneurysm was noted at the right VA. We performed reconstructive embolization and the patient eventually recovered with minimal persistent symptoms.

Conclusion:

Since the outcomes of contralateral VAD complicated by infarction or hemorrhage are poor, and most cases develop within 7–14 days after endovascular internal trapping for unilateral VAD, performing bilateral radiographic reinspection within this time frame is recommended for early detection and preventive treatment of possible contralateral VADs.

Diagnostic Performance of High-Resolution Vessel Wall Magnetic Resonance Imaging and Digital Subtraction Angiography in Intracranial Vertebral Artery Dissection

Purpose: Intracranial vertebral artery dissection (VAD) is being increasingly recognized as a leading cause of Wallenberg syndrome and subarachnoid hemorrhage. Conventional angiography is considered the standard diagnostic modality, but the diagnosis of VAD remains challenging. This study aimed to compare the diagnostic performance of high-resolution vessel wall imaging (HR-VWI) with digital subtraction angiography (DSA) for intracranial VAD. Materials and methods: Twenty-four patients with 27 VADs, who underwent both HR-VWI and DSA within 2 weeks, were consecutively enrolled in the study from March 2016 to September 2020. HR-VWI and DSA were performed to diagnose VAD and to categorize its angiographic features as either definite dissection or suspicious dissection. Features of HR-VWI were used to evaluate direct arterial wall imaging. The reference standard was set from the clinicoradiologic diagnosis. Two independent raters evaluated the angiographic features, dissection signs, and interrater agreement. Each subject was also dichotomized into two groups (suspicious or definite VAD) in each modality, and diagnosis from HR-VWI and DSA was compared with the final diagnosis by consensus. Results: HR-VWI had higher agreement (90.6% vs. 53.1%) with the final diagnosis and better interrater reliability (kappa value (κ) = 0.91; 95% confidence interval (CI) = 0.64–1.00) compared with DSA (κ = 0.58; 95% CI = 0.35–1.00). HR-VWI provided a more detailed identification of dissection signs (77.7% vs. 22.2%) and better reliability (κ = 0.88; 95% CI = 0.58–1.00 vs. κ = 0.75; 95% CI = 0.36–1.00), compared to DSA. HR-VWI was comparable to DSA for the depiction of angiographic features for VAD. Conclusions: HR-VWI may be useful to evaluate VAD, with better diagnostic confidence compared to DSA.

Posterior Communicating Artery Hypoplasia: A Risk Factor for Vertebral Artery Dissection Causing Subarachnoid Hemorrhage

OBJECTIVE

Subarachnoid hemorrhage due to vertebral artery dissection is often fatal; however, its anatomical predictors remain unclear. We conducted a retrospective hospital-based case-control study to evaluate whether variations in the posterior communicating artery are associated with the risk of vertebral artery dissection with subarachnoid hemorrhage.

MATERIALS AND METHODS

We obtained data from patients who underwent computed tomography angiography at our hospital between April 2010 and March 2020. Based on the connection between the anterior and posterior circulation of the arterial circle of Willis, the patients were categorized into a separated group (posterior communicating artery hypoplasia) and a connected group (all others). We evaluated the association between the development of posterior communicating artery and subarachnoid hemorrhage due to vertebral artery dissection using multivariate logistic regression analysis.

RESULTS

Thirty-eight patients had subarachnoid hemorrhage due to vertebral artery dissection and 76 were identified as age- and sex-matched controls. In conditional multivariate logistic regression analysis, the separated group showed a significant association with subarachnoid hemorrhage due to vertebral artery dissection, with an adjusted odds ratio of 2.8 (95% confidence interval, 1.2-6.5; P = 0.021).

CONCLUSIONS

The present study demonstrates that posterior communicating artery hypoplasia may be associated with subarachnoid hemorrhage due to vertebral artery dissection. Our results highlight the importance of anatomical variations in the cerebral artery and provide evidence to help develop preventive measures against strokes.

Spontaneous Intracranial Artery Dissection causing Subarachnoid Hemorrhage: Importance of Short-Term Surveillance

Hemorrhagic intracranial artery dissections are unstable lesions, with a high propensity for rebleeding (up to 40%) in the acute period. Imaging plays an important role in the diagnosis and management of intracranial artery dissections. In this paper, we describe 2 cases in which the dissected intracranial artery underwent rapid morphological change within 3 days or less, highlighting the importance of short-term follow-up imaging in patients with these hemorrhagic lesions.

A Case of Intracranial Vertebral Artery Dissection Undetected by CT, MRI, and MRA at the Onset of Headache That Caused Subarachnoid Hemorrhage Seven Days Later

Objective

We report a patient with normal imaging findings at the onset of preceding headache who developed subarachnoid hemorrhage (SAH) due to intracranial vertebral artery dissection 7 days later.

Case Presentation

A 51-year-old woman with a history of chronic headache visited our emergency outpatient department with a complaint of mild to moderate right nuchal pain. CT, MRA, and MRI (diffusion-weighted image, T2-weighted image, FLAIR, MR cisternography, and basi-parallel anatomical scanning) were normal. Seven days later, she was admitted to our hospital with sudden disturbance of consciousness. CT revealed SAH and CTA demonstrated dilatation of the right vertebral artery (VA). The dilated lesion with an intimal flap on the right VA proximal to the posterior inferior cerebellar artery was confirmed on DSA. The dilated lesion and the proximal VA were occluded endovascularly using coils. The condition of the patient improved gradually, and she was transferred to the rehabilitation hospital on day 45 with a modified Rankin Scale score of 2.

Conclusion

The clinical course of the presented case, although rare, should be kept in mind in daily clinical practice.

Usefulness of 3D High-resolution Vessel Wall MRI in Diffuse Nonaneurysmal SAH Patients

PURPOSE

In 15-20% of patients with nontraumatic diffuse subarachnoid hemorrhage (SAH), the initial conventional angiography does not reveal a causative vascular abnormality, such as intracranial aneurysm. In this study, we evaluated clinical utility of 3D high-resolution vessel wall magnetic resonance imaging (HR-VWI) in patients with diffuse nonaneurysmal SAH.

METHODS

A total of 17 patients with diffuse nonaneurysmal SAH were included in this retrospective study. We characterized demographics and HR-VWI findings and reviewed the clinical management and outcomes.

RESULTS

Of the patients 14 (14/17; 82.4%,) showed abnormal findings on HR-VWI, including 5 with intracranial dissections (29.4%), 3 with blood blister-like aneurysm (17.6%), 1 with ruptured fusiform aneurysm (5.9%), and 5 with focal nodular wall enhancement without unclassified pathology (29.4%). Of these patients were treated with endovascular management. Most patients (16/17) had a favorable modified Rankin scale scores of 0-2 on discharge.

CONCLUSION

The 3D HR-VWI revealed various hidden pathologies, such as intracranial arterial dissection, blood blister-like aneurysm, and fusiform aneurysm in patients with diffuse nonaneurysmal SAH. In addition, 3D HR-VWI had an impact on the management of SAH. The 3D HR-VWI can be a complementary diagnostic method for patients with diffuse nonaneurysmal SAH in a research or clinical setting.

Case Report: De novo Vertebral Artery Dissection After Intravascular Stenting of the Contralateral Unruptured Vertebral Artery Aneurysm

Spontaneous vertebral artery dissecting aneurysm has been increasingly attributed as a major cause of focal neurological deficits due to vertebrobasilar artery ischemia or subarachnoid hemorrhage (SAH). Although the development of spontaneous vertebral artery dissecting aneurysm (VADA) is rare, de novo VADA after treatment of contralateral vertebral artery (VA) is more less frequently observed. There are only a few reports related to de novo VADA after treatment of the contralateral VA in the medical literature. The mechanisms responsible for de novo dissection after treatment of unilateral VADA are still not clearly understood. In this manuscript, we report an unusual case of a patient with a de novo VADA after placement of a pipeline embolization device (PED) stent on the contralateral VA along with a thorough review of the literature. A 42-years old male patient was referred to the hospital with sudden onset of dizziness, nausea, and vomiting. Initial digital subtraction angiography (DSA) images demonstrated a VADA in the fourth segment of the left VA without the involvement of the posterior inferior cerebellar artery (PICA). There were no significant abnormalities found in the right vertebral artery. He underwent an endovascular pipeline embolization to treat the dissecting aneurysm (DA). Surprisingly, follow-up DSA imaging 14 months after the initial treatment showed a segmental dilatation and narrowing of the right VA, which suggested a de novo VADA on the right side that had occurred postoperatively. This was followed by a tent-assisted coil embolization therapy for occluding this de novo VADA. This patient showed an uneventful postoperative course with no neurological abnormalities. In addition to hemodynamic stress changes, the unique clinicopathological features of dissecting aneurysms may contribute significantly to the pathogenesis of de novo VA dissection. Given that VA in VADA patients may be vulnerable on both sides, it is important to consider the risk of de novo dissection after initial aneurysm treatment. The bilateral vertebral artery has to be carefully observed when treating any VADA patient to prevent any complications.

Intramural Hematoma Shape and Acute Cerebral Infarction in Intracranial Artery Dissection: A High-Resolution Magnetic Resonance Imaging Study

BACKGROUND

Intracranial artery dissection (IAD) is gaining recognition as an important cause of stroke, but limited information is available about the morphology of the dissection. This study aimed to investigate the relationship between acute cerebral infarctions and the shape of hematoma in patients with IADs using high-resolution magnetic resonance imaging (HRMRI).

METHODS

We enrolled consecutive patients who presented with vascular headaches, transient ischemic attacks, or ischemic strokes with acute IAD confirmed by HRMRI using key pathognomonic radiological findings of IAD, including intimal flap, intramural hematoma (IMH), and double lumen. All patients were enrolled and HRMRI was performed, both within 7 days of symptom onset. All patients with acute ischemic infarction within 7 days were enrolled. Patients were divided into 2 groups: those with a proximal dominant intramural hematoma (PIMH) and those with a distal dominant intramural hematoma (DIMH). A PIMH was defined as when the volume of the hematoma in the proximal region was greater than that in the distal region, and a DIMH was defined as when the distal region was greater than that in the proximal region. Clinical and radiological characteristics between the 2 groups were compared using univariable and multivariable logistic regression.

RESULTS

The mean age of the 42 participants was 52.6 ± 12.7 years, and 24 (57.1%) were male. Twenty-seven (64.3%) had a PIMH and 15 (35.7%) had a DIMH. Thirty-six (85.7%) showed a double lumen and 27 (64.3%) showed a dissecting flap. Acute infarction was observed in 31 (73.8%) patients. Patients with PIMHs showed a higher prevalence of cerebral infarction than those with DIMHs (96.3 vs. 33.3%; p < 0.001). Univariable (odds ratio [OR] 52.00; 95% confidence interval [CI] 5.386-502.082; p = 0.001) and multivariable (OR 65.43; 95% CI 5.20-822.92; p = 0.001) analyses showed that only dissection type was independently associated with the risk of cerebral infarction.

CONCLUSION

In patients with cerebral artery dissections, the shape of IMHs was independently associated with cerebral infarction. PIMHs may be more closely associated with cerebral infarctions than DIMHs.

Characteristics of Clinical Symptoms, Cerebral Images and Stroke Etiology in Vertebro-Basilar Artery Fenestration-Related Infarction

Cerebral artery fenestration is a rare variant of the vascular architecture, but its existence is well documented. The common site of fenestration is the vertebra-basilar artery and it may be found incidentally with subarachnoid hemorrhage. However, fenestration-related cerebral infarction is rare. We analyzed the clinical characteristics, stroke etiology, and image findings of fenestration-related cerebral infarction of the vertebrobasilar artery. We reviewed our hospital records and previously published reports to find cases of fenestration-related cerebral infarction. We excluded those with unknown clinical features or radiological findings. We retrieved 4 cases of fenestration-related infarction from our hospital, in which vascular change, headache, vertigo/dizziness, and dissection in stroke etiology were detected. In eight previously reported cases of fenestration-related infarction, similar vascular changes were noted, but they were mainly diagnosed as embolic stroke of undetermined source. However, based on the criteria for dissection in this study, dissection as the stroke etiology was suspected in the previously reported cases. Many hypotheses have been proposed for the development of dissection, thrombus, and aneurysms in fenestration. Although an embryological and morphological study is needed, clinicians must consider basilar artery fenestration-related infarction as a differential diagnosis and intensive non-invasive image study is recommended.

A case of unilateral vertebral artery dissection progressing in a short time period to bilateral vertebral artery dissection

Background

Vertebral artery dissection (VAD) is an important cause of stroke in young and middle- aged people. Bilateral occurrence of VAD is generally considered rare, but the number of reports of bilateral VAD has been increasing in recent years. In this paper, we report a case of de novo VAD on the contralateral side presenting with subarachnoid hemorrhage in the acute stage of cerebral infarction due to unilateral VAD.

Case Description

A 52-year-old man developed sudden-onset left occipital headache, dizziness, dysphagia, and right-sided hemiparesthesia and was admitted to our hospital. Head magnetic resonance imaging on admission showed a left lateral medullary infarction due to the left VAD. At this point, the right vertebral artery was normal. However, on day 9 after onset, he suddenly presented with subarachnoid hemorrhage due to the right VAD. Emergency endovascular treatment was performed for the dissecting aneurysm of the right vertebral artery. The patient's condition improved gradually after the procedure, and he was discharged with a modified Rankin Scale score of 1.

Conclusion

Bilateral occurrence of VAD may be more common than previously believed. Even in cases of unilateral VAD, we need to pay attention to the occurrence of de novo VAD on the contralateral side.

Spinal Cord Infarction in the Region of the Posterior Spinal Artery After Embolization for Vertebral Artery Dissection

BACKGROUND

Endovascular surgery for vertebral artery dissections (VADs) carries the risk of spinal cord infarction (SCI). Although SCI in the region of the anterior spinal artery (ASA) has been reported, SCI in the region of the posterior spinal artery (PSA) is rare.

OBJECTIVE

To investigate PSA infarction after endovascular surgery for VAD.

METHODS

Infarction in the region of the PSA after endovascular surgery for VADs carried out in consecutive 21 cases was investigated. The variables of aneurysmal location, status, intra-aneurysmal thrombosis, antithrombotic therapy, and endovascular procedure were investigated in relation to the occurrence of spinal cord or brain stem infarction.

RESULTS

Thirteen cases were unruptured aneurysms, and 8, ruptured aneurysms. The endovascular surgical method was internal trapping in 10 cases, stent-assisted coil embolization in 8 cases, and proximal occlusion (PO) in 3 cases. Periprocedural symptomatic infarction was detected in 4 of the 21 cases (19%): 3 SCIs and 1 lower medulla infarction, after 1 stent-assisted coil embolization and 3 PO. All 3 symptomatic SCIs were PSA infarction. On univariate analysis, the variables of posterior inferior cerebellar artery-involved-type, PO, and intraprocedural proximal flow arrest were significantly correlated with occurrence of PSA infarction.

CONCLUSION

PSA infarction after endovascular surgery for VAD seems not to be a rare potential complication. Insufficiency of collateral blood flow and artery-to-artery embolism due to intraprocedural flow stagnation of the VA seem to be the possible mechanisms of PSA infarction in addition to previously reported mechanisms such as direct obliteration by the embolic materials and extended thrombosis of the VA stump.

Craniocervical Dissections: Radiologic Findings, Pitfalls, Mimicking Diseases: A Pictorial Review

Background:

Craniocervical Dissections (CCD) are a crucial emergency state causing 20% of strokes in patients under the age of 45. Although DSA (digital substraction angiography) is regarded as the gold standard, noninvasive methods of CT, CTA and MRI, MRA are widely used for diagnosis.

Aim:

Our aim is to illustrate noninvasive imaging findings in CCD.

Conclusion:

Emphasizing on diagnostic pitfalls, limitations and mimicking diseases.

Treatment Strategies of Subarachnoid Hemorrhage from Bilateral Vertebral Artery Dissection: A Case Report and Literature Review Focusing on the Availability of Stent Placement

BACKGROUND

Bilateral vertebral artery dissection (VAD) may result in subarachnoid hemorrhage (SAH). However, a variety of factors contribute to the difficulties with treating SAH. We report a case of bilateral VAD with SAH, as well as a literature review.

CASE DESCRIPTION

A 32-year-old woman developed headache. Computed tomography demonstrated diffuse SAH, and 3-dimensional computed tomography indicated bilateral VAD. Her left vertebral artery was severely stenosed, and the basilar artery retrogradely flowed via the posterior communicating artery. Her bilateral VAD was trapped with the use of staged craniotomy. The postoperative course was uneventful for 13 days; however, severe neurologic deterioration remained in the area of the cerebral infarction, due to vasospasm of the internal carotid artery. This is the first report of hemorrhagic bilateral VAD treated with bilateral trapping and aggressive spasm treatment in the acute phase. However, the treatment was not successful.

CONCLUSIONS

Because of the increasing use of stent therapy, there has been a shift toward this treatment choice. For cases in which stents cannot be used, treatment methods based on prestenting protocols are helpful. A literature review indicated that conservative treatment for 2 weeks, in which vasospasm and rebleeding are controlled, may be considered compared with acute-stage stent treatment. Following our literature review, in situations in which stents cannot be used, only the ruptured side should be trapped with strict blood pressure control and detailed radiological images should be observed for 2 weeks. In conclusion, patient selection is essential to subject the patient to open surgery in such cases.

Treatment Strategy for Isolated Posterior Inferior Cerebellar Artery Dissection

OBJECTIVE

Isolated dissections that develop on the posterior inferior cerebellar artery (PICA) require intensive treatment because of their potential fatality. However, because of the rarity of these dissections, the optimal treatment has not yet been established.

METHODS

We retrospectively reviewed the clinical records of all patients who underwent any PICA dissection treatment in our institute over the last 4 years. Ten patients were enrolled, including 7 patients with subarachnoid hemorrhage (SAH) and 3 with PICA territory infarction. Dissection was seen at the proximal portion in 8 patients, whereas the remaining 2 patients showed distal PICA dissecting aneurysms.

RESULTS

Among the 7 patients with hemorrhage, 5 were actively treated (trapping and bypass, 2 patients; surgical clipping, 1 patient; coil embolization, 2 patients). Conservative management was performed in the other 2 patients. Among the 3 patients with infarction, 2 received conservative treatment. Endovascular treatment was performed in 1 patient, who showed rapid progression, aneurysm formation, and conversion to massive SAH within 10 days after the initial attack. Although 7 patients showed relatively good outcomes (modified Rankin Scale score, ≤2) after 30 days of follow-up, 1 patient had a final modified Rankin Scale score of 3. In addition, the other 2 patients (1 in each group) died as a result of major SAH.

CONCLUSIONS

Given the dynamic clinical course and potential fatality of PICA dissection, meticulous evaluation, intensive treatment with a diverse range of modalities, and proper follow-up are required for patients with PICA dissection to achieve favorable outcomes.

Headache in Intracranial and Cervical Artery Dissections

Dissection refers to a tear in the wall of an artery, with the two main types being intracranial or extracranial. Dissections tend to occur most commonly in the young, sometimes secondary to trauma involving the neck. To confirm a dissection, some type of vessel imaging is necessary, including magnetic resonance angiography (MRA), computed tomography angiography (CTA), or angiography. The most common presentation of a dissection (especially extracranial) is pain, usually head and neck pain along with a Horner's syndrome. Patients may also present with ischemic symptoms, including transient ischemic attack (TIA) or stroke, which may also be a complication of a dissection. Although headache is a common presentation, there is little research into phenotype or long-term outcomes. There are a number of case reports detailing the phenotypes of headaches that may be present in dissection, including a migraine-like or hemicrania-like headache. Dissections are usually treated with some type of anti-platelet or anti-coagulation, although there are only a few randomized controlled trials. In a new acute headache, dissection is an important diagnosis to keep in mind.

Surgical Management of Intracranial Artery Dissection

Intracranial artery dissection (IAD) is a relatively rare cause of stroke, but it has been recognized increasingly with recent advances of the neuroimaging technique. Since rebleeding occurs frequently in the acute stage in the ruptured IAD, urgent surgical treatment should be performed to prevent rebleeding. On the other hand, surgical treatment for unruptured IAD is controversial because it has little risk for bleeding. However, surgical treatment for unruptured IAD may be considered if the formation or enlargement of the aneurysmal dilatation has been confirmed. Since there are several proposed surgical strategies for IAD, it is important to select an appropriate strategy on a case-by-case basis. If the risk of infarction due to vessel occlusion is high, combined bypass surgery should be considered.

Evaluation of the Arterial Wall in Vertebrobasilar Artery Dissection Using High-Resolution Magnetic Resonance Vessel Wall Imaging

BACKGROUND

High-resolution magnetic resonance vessel wall imaging (HRMR-VWI) has been used to explore vascular diseases such as vasculitis and vulnerable plaque of intracranial arteries. Although vessel wall inflammation is suspected as one of the causes of cerebral arterial dissection, there have been few reports regarding the application of HRMR-VWI to arterial dissection. We have therefore evaluated the efficacy of HRMR-VWI in patients with vertebrobasilar artery dissection.

METHODS

HRMR-VWI was performed on 5 patients who had been diagnosed with nonhemorrhagic vertebrobasilar artery dissection.

RESULT

Four patients exhibited vessel wall enhancement on HRMR-VWI, the range of which corresponded with the dissection sites identified by cerebral angiogram, magnetic resonance imaging, or magnetic resonance angiography. The enhancements observed in all cases were extensive as compared with the findings of conventional angiography.

CONCLUSION

HRMR-VWI is thought to elucidate the condition of the affected vessel wall more in detail as compared with conventional methods.

Epidemiology, pathophysiology, diagnosis, and management of intracranial artery dissection

Spontaneous intracranial artery dissection is an uncommon and probably underdiagnosed cause of stroke that is defined by the occurrence of a haematoma in the wall of an intracranial artery. Patients can present with headache, ischaemic stroke, subarachnoid haemorrhage, or symptoms associated with mass effect, mostly on the brainstem. Although intracranial artery dissection is less common than cervical artery dissection in adults of European ethnic origin, intracranial artery dissection is reportedly more common in children and in Asian populations. Risk factors and mechanisms are poorly understood, and diagnosis is challenging because characteristic imaging features can be difficult to detect in view of the small size of intracranial arteries. Therefore, multimodal follow-up imaging is often needed to confirm the diagnosis. Treatment of intracranial artery dissections is empirical in the absence of data from randomised controlled trials. Most patients with subarachnoid haemorrhage undergo surgical or endovascular treatment to prevent rebleeding, whereas patients with intracranial artery dissection and cerebral ischaemia are treated with antithrombotics. Prognosis seems worse in patients with subarachnoid haemorrhage than in those without.

Endovascular Treatment of Dissecting Aneurysms of the Posterior Inferior Cerebellar Artery and Predictors of Outcome

BACKGROUND

Isolated dissecting aneurysms of the posterior inferior cerebellar artery (PICA) are rare lesions, which carry high risk of rebleeding and mortality. However, the existing literature concerning predictors of outcome after endovascular treatment is limited and controversial. Our present study retrospectively reviewed and analyzed the clinical outcome of endovascular treatment-ruptured PICA-dissecting aneurysms and explored the predictors of outcome.

METHODS

We retrospectively reviewed 17 consecutive patients with ruptured PICA dissecting aneurysms that underwent endovascular treatment from January 2003 to January 2014. Nine patients underwent selective coiling, whereas 7 patients underwent parent artery occlusion and 1 patient underwent stent-assisted coiling. Follow-up outcomes were evaluated using the modified Rankin Scale. The clinical outcomes of patients were categorized as favorable (modified Rankin Scale [mRS] score 0-1) or unfavorable (mRS score 2-6).

RESULTS

Favorable outcomes (mRS score 0-1) were obtained in 13 of 17 patients. Post-treatment recurrence occurred in 1 patient with selective coiling in the 15-month follow-up, and the patient received stent-assisted coiling. The only patients with stent-assisted coiling developed PICA occlusion during follow-up. Aneurysm located in distal segment usually presented with intraventricular hemorrhage (P = .015). Hypertension, coexisting hydrocephalus, and time to operation (latter than 2 weeks) were associated with unfavorable outcome.

CONCLUSIONS

Endovascular treatment of isolated dissecting aneurysm of PICA had excellent clinical outcomes, hypertension, coexisting hydrocephalus, and time to operation (latter than 2 weeks), which were associated with unfavorable outcome. Long-term follow-ups are necessary to provide stronger conclusions.

Are blood blister-like aneurysms a specific type of dissection? A comparative study of blood blister-like aneurysms and ruptured mizutani type 4 vertebral artery dissections

Objective

Blood blister-like aneurysms (BBAs) resemble arterial dissections. The purpose of this study was to investigate the relationship between these two disease entities and highlight commonalities and distinct features.

Methods

Among 871 consecutive patients with aneurysmal subarachnoid hemorrhage, 11 BBAs of internal carotid artery and seven vertebral artery dissections (VADs) with a short segmental eccentric dilatation (Mizutani type 4), which is morphologically similar to a BBA, were selected. The following clinical factors were studied in each group : age, gender, risk factors, Hunt and Hess grade (HHG), Fisher grade (FG), vasospasms, hydrocephalus, perioperative rebleeding rate, and treatment outcome.

Results

The mean age was 47.9 years in the BBAs group and 46.4 years in the type 4 VADs group. All the BBA patients were female, whereas there was a slight male predominance in the type 4 VAD group (male : female ratio of 4 : 3). In the BBA and type 4 VAD groups that underwent less aggressive treatment to save the parent artery, 29% (n=2/7) and 66.6% (n=2/3), respectively, eventually required retreatment. Perioperative rebleeding occurred in 72.7% (n=8) and 28.6% (n=2) of patients in the BBA and type 4 VAD groups, respectively. There was no statistical difference in the other clinical factors in both groups, except for the male dominancy in the type 4 VAD group (p=0.011).

Conclusion

BBAs and ruptured type 4 VADs have a similar morphological appearance but there is a distinct clinical feature in gender and perioperative rebleeding rates. Complete isolation of an aneurysm from the parent artery might be the most important discipline for the treatment of these diseases.

Cervical arterial dissections and association with cervical manipulative therapy: a statement for healthcare professionals from the american heart association/american stroke association

PURPOSE

Cervical artery dissections (CDs) are among the most common causes of stroke in young and middle-aged adults. The aim of this scientific statement is to review the current state of evidence on the diagnosis and management of CDs and their statistical association with cervical manipulative therapy (CMT). In some forms of CMT, a high or low amplitude thrust is applied to the cervical spine by a healthcare professional.

METHODS

Members of the writing group were appointed by the American Heart Association Stroke Council's Scientific Statements Oversight Committee and the American Heart Association's Manuscript Oversight Committee. Members were assigned topics relevant to their areas of expertise and reviewed appropriate literature, references to published clinical and epidemiology studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize existing evidence and to indicate gaps in current knowledge.

RESULTS

Patients with CD may present with unilateral headaches, posterior cervical pain, or cerebral or retinal ischemia (transient ischemic or strokes) attributable mainly to artery-artery embolism, CD cranial nerve palsies, oculosympathetic palsy, or pulsatile tinnitus. Diagnosis of CD depends on a thorough history, physical examination, and targeted ancillary investigations. Although the role of trivial trauma is debatable, mechanical forces can lead to intimal injuries of the vertebral arteries and internal carotid arteries and result in CD. Disability levels vary among CD patients with many having good outcomes, but serious neurological sequelae can occur. No evidence-based guidelines are currently available to endorse best management strategies for CDs. Antiplatelet and anticoagulant treatments are both used for prevention of local thrombus and secondary embolism. Case-control and other articles have suggested an epidemiologic association between CD, particularly vertebral artery dissection, and CMT. It is unclear whether this is due to lack of recognition of preexisting CD in these patients or due to trauma caused by CMT. Ultrasonography, computed tomographic angiography, and magnetic resonance imaging with magnetic resonance angiography are useful in the diagnosis of CD. Follow-up neuroimaging is preferentially done with noninvasive modalities, but we suggest that no single test should be seen as the gold standard.

CONCLUSIONS

CD is an important cause of ischemic stroke in young and middle-aged patients. CD is most prevalent in the upper cervical spine and can involve the internal carotid artery or vertebral artery. Although current biomechanical evidence is insufficient to establish the claim that CMT causes CD, clinical reports suggest that mechanical forces play a role in a considerable number of CDs and most population controlled studies have found an association between CMT and VAD stroke in young patients. Although the incidence of CMT-associated CD in patients who have previously received CMT is not well established, and probably low, practitioners should strongly consider the possibility of CD as a presenting symptom, and patients should be informed of the statistical association between CD and CMT prior to undergoing manipulation of the cervical spine.

The interaction between stent(s) implantation, PICA involvement, and immediate occlusion degree affect symptomatic intracranial spontaneous vertebral artery dissection aneurysm (sis-VADA) recurrence after reconstructive treatment with stent(s)-assisted coiling

Objectives

We aimed to evaluate risk factors of sis-VADAs recurrence after reconstructive treatment based on 113 reconstructed lesions.

Methods

A total of 111 patients (M:F = 68:43; median age, 47 years) with 113 sis-VADAs underwent reconstruction from October 2000 to March 2011, using stent(s) and coils. Treatments and predictors of recurrence were retrospectively analysed.

Results

Fifty-eight sis-VADAs underwent single-stent treatment, and the remaining 55 sis-VADAs underwent treatment with 2-4 overlapping stents. Follow-up angiography was available for 94 sis-VADAs 12 -78 months, with recurrence in ten patients, including seven angiographic recurrences and three post-treatment haemorrhagic recurrences. A higher rate of post-treatment recurrence was observed in the single stent group than in the multiple stents group (p = 0.010). The interaction between stent (s) implantation and immediate occlusion degree (odds ratio [OR] =3.152; 95 % confidence interval [CI], 1.293-7.686; p = 0.012), between stent (s) implantation and the posterior inferior cerebellar artery (PICA) involvement (OR = 4.607; 95 % CI, 1.172-18.113; p = 0.029), and between PICA involvement and immediate occlusion degree (OR = 5.018; 95 % CI, 1.263-19.933; p = 0.022) affect recurrence in the reconstructed sis-VADAs.

Conclusions

This single centre cohort study indicated that the interaction effect between stent (s) implantation, PICA involvement, and immediate occlusion degree were closely associated with recurrence after reconstructive treatment of sis-VADA.

Key Points

• The interaction between stent (s) and immediate occlusion degree affect aneurysmal recurrence

• The interaction between stent and PICA involvement affect aneurysmal recurrence

• The interaction between PICA involvement and immediate occlusion degree affect aneurysmal recurrence

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-014-3225-7) contains supplementary material, which is available to authorized users.

Ethanol, Trauma, and the Brain

Alcohol intoxication plays a significant and causal role in various fatal injuries. In comparison to sober individuals, intoxicated people have a greater generic risk for being involved in hazardous activities that may result in fatal injuries. However, it is not clear whether the biological effects of acute alcohol intoxication result in worse injuries than those sustained by sober individuals who are injured by identical mechanisms. Alcohol intoxication has a neuroprotective effect in experimental animal models of traumatic brain injury (TBI) but the evidence for a similar effect in humans is controversial. Earlier studies found such a protective effect, but more recent large epidemiological studies have not confirmed this finding; some studies also suggest a dose-related protective or exacerbating effect of alcohol intoxication on TBI. There are two apparent alcohol-associated syndromes in which an otherwise survivable blunt force impact to the head of an intoxicated individual is fatal at the scene. The first is a fatal cardiorespiratory arrest (the so-called alcohol concussion syndrome or “commotio medullaris”); the second is “traumatic basilar subarachnoid hemorrhage” (secondary to tears in the cerebral arteries, particularly the intracranial and extracranial vertebral arteries).

Reconstructive Treatment of Ruptured Intracranial Spontaneous Vertebral Artery Dissection Aneurysms: Long-Term Results and Predictors of Unfavorable Outcomes

Introduction

Few studies focused on predictors of unfavorable outcomes (modified Rankin Scale, 2–6) after reconstructive treatment of the ruptured intracranial spontaneous vertebral artery dissection aneurysms (ris-VADAs), which was evaluated based on 57 reconstructed lesions in this study.

Methods

Results of 57 consecutive patients (M:F = 29∶28; median age, 48 years; range, 27 to 69 years) harboring 57 ris-VADAs, which were treated with coils combined with single stent(n = 32), double overlapping stents (n = 16), and triple overlapping stents (n = 9) between October 2000 to March 2011, were retrospectively reviewed and analyzed.

Results

The available (n = 54) mean durations of angiographic and clinical follow-ups were 27 months (range, 12 to 78) and 62 months (range, 12 to 132), respectively. The involvement of PICA (p = 0.004), size of lesions (p = 0.000), quantity of stent (p = 0.001), and coil type (p = 0.002) affected the immediate obliteration grade, which was only risk factor for angiographic recurrences (p = 0.031). Although the post-treatment outcomes did not differ between single stent and multiple stents (p = 0.434), 5 angiographic recurrences, 1 rebleeding and 1 suspected rebleeding, all occurred in partial obliteration after single-stent-assisted coiling. Progressive thrombosis and in-stent obliteration were not detected on follow-up angiograms. Older age (odds ratio [OR] = 1.090; 95% confidence interval [CI], 1.004–1.184; p = 0.040) and unfavorable Hunt-Hess scale (OR = 4.289; 95%CI, 1.232–14.933; p = 0.022) were independent predictors of unfavorable outcomes in the reconstructed ris-VADAs.

Conclusions

Immediate obliteration grade was only risk factor for angiographic recurrence after reconstructive treatment. Unfavorable Hunt-Hess grade and older age were independent predictors of unfavorable outcomes in ris-VADAs.

Pathomorphometry of ruptured intracranial vertebral arterial dissection: adventitial rupture, dilated lesion, intimal tear, and medial defect

OBJECT

Subarachnoid hemorrhage (SAH) due to ruptured intracranial vertebral artery (VA) dissection is a life-threatening disease. Angiographic and symptomatic prognostic factors for rupture and rerupture have been investigated, but the pathological characteristics have not been fully investigated. The authors aimed to investigate these features by performing a pathomorphometic study of ruptured intracranial VA dissections.

METHODS

This study included 50 administrative autopsy cases of fatal SAH due to ruptured intracranial VA dissection among 517 fatal nontraumatic cases of SAH occurring between March 2003 and May 2011. Pathomorphometry was performed using serial 5-μm histological cross-sections with elastica van Gieson staining from each 0.2-mm segment around the ruptured intracranial VA. The longitudinal lengths of 4 types of vascular lesions-adventitial ruptures, dilated lesions where the internal elastic lamina (IEL) was ruptured with adventitial extension, intimal tears where the IEL was ruptured, and medial defects-were calculated based on the numbers of the slides in which these lesions were continuously detected (minimum 2 adjoining slides). The distance from the vertebrobasilar junction to the center of adventitial rupture was also calculated in 37 cases.

RESULTS

All cases showed one adventitial rupture with a mean length of about 1.9±1.1 mm. The center of the adventitial rupture was located 5.0-26.8 mm (mean 14.6±5.5 mm) from the intracranial VA bifurcation. Adventitial ruptures existed in the centers of dilated lesions, where the adventitia was highly extended. Other vascular lesions were serially observed surrounding the adventitial rupture. The mean lengths of dilated lesions, intimal tears, and medial defects were 9.4±4.8 mm, 13.2±6.3 mm, and 15.6±7.2 mm, respectively. The lengths between proximal lesions and distal lesions from the center of the adventitial rupture for both medial defects and intimal tears were significantly longer at proximal lesions than at distal ones (chi-square test, p<0.01).

CONCLUSIONS

Every ruptured intracranial VA dissection has a single point of adventitial rupture where the adventitia was maximally extended, so dilation appears to be a valuable predictive factor for hemorrhagic intracranial VA dissections. The adventitial ruptures were as small as 2 mm in length, and clinically detectable dilated lesions were about 9 mm in length. However, vascular vulnerability caused by IEL ruptures and medial defects existed more widely across a length of VA of 1.3-1.5 cm. Comparatively broader protection of the intracranial VA than the clinically detected area of dissection might be desirable to prevent rebleeding. Broader protection of proximal lesions than distal lesions might be effective from the viewpoint of site distribution of vascular lesions and blood flow alteration to the pseudolumen caused by the dissecting hematoma. Medial defects are the most widely seen lesions among the 4 types of vascular lesions studied. Medial degenerative disease, known as segmental arterial mediolysis, is suspected in the pathogenesis of intracranial VA dissections.

Intracranial vertebral artery dissections: evolving perspectives

Intracranial vertebral artery dissection (VAD) represents the underlying etiology in a significant percentage of posterior circulation ischemic strokes and subarachnoid hemorrhages. These lesions are particularly challenging in their diagnosis, management, and in the prediction of long-term outcome. Advances in the understanding of underlying processes leading to dissection, as well as the evolution of modern imaging techniques are discussed. The data pertaining to medical management of intracranial VADs, with emphasis on anticoagulants and antiplatelet agents, is reviewed. Surgical intervention is discussed, including, the selection of operative candidates, open and endovascular procedures, and potential complications. The evolution of endovascular technology and techniques is highlighted.

Medullary infarction as a poor prognostic factor after internal coil trapping of a ruptured vertebral artery dissection

OBJECT

Internal coil trapping is a treatment method used to prevent rebleeding from a ruptured intracranial vertebral artery dissection (VAD). Postoperative medullary infarctions have been reported as a complication of this treatment strategy. The aim of this study was to determine the relationship between a postoperative medullary infarction and the clinical outcomes for patients with ruptured VADs treated with internal coil trapping during the acute stage of a subarachnoid hemorrhage (SAH).

METHODS

A retrospective study identified 38 patients who presented between 2006 and 2011 with ruptured VADs and underwent internal coil trapping during the acute stage of SAH. The SAH was identified on CT scanning, and the diagnosis for VAD was rendered by cerebral angiography. Under general anesthesia, the dissection was packed with coils, beginning at the distal end and proceeding proximally. When VAD involved the origin of the posterior inferior cerebellar artery (PICA) with a large cerebellar territory, an occipital artery (OA)-PICA anastomosis was created prior to internal coil trapping. The pre- and postoperative radiological findings, clinical course, and outcomes were analyzed.

RESULTS

The internal coil trapping was completed within 24 hours after admission. An OA-PICA anastomosis followed by internal coil trapping was performed in 5 patients. Postoperative rebleeding did not occur in any patient during a mean follow-up period of 16 months. The postoperative MRI studies showed medullary infarctions in 18 patients (47%). The mean length of the trapped VAD for the infarction group (15.7 ± 6.0 mm) was significantly longer than that of the noninfarction group (11.5 ± 4.3 mm) (p = 0.019). Three of the 5 patients treated with OA-PICA anastomosis had postoperative medullary infarction. The clinical outcomes at 6 months were favorable (modified Rankin Scale Scores 0-2) for 23 patients (60.5%) and unfavorable (modified Rankin Scale Scores 3-6) for 15 patients (39.5%). Of the 18 patients with postoperative medullary infarctions, the outcomes were favorable for 6 patients (33.3%) and unfavorable for 12 patients (66.7%). A logistic regression analysis predicted the following independent risk factors for unfavorable outcomes: postoperative medullary infarctions (OR 21.287 [95% CI 2.622-498.242], p = 0.003); preoperative rebleeding episodes (OR 7.450 [95% CI 1.140-71.138], p = 0.036); and a history of diabetes mellitus (OR 45.456 [95% CI 1.993-5287.595], p = 0.013).

CONCLUSIONS

A postoperative medullary infarction was associated with unfavorable outcomes after internal coil trapping for ruptured VADs. Coil occlusion of the long segment of the VA led to medullary infarction, and an OA-PICA bypass did not prevent medullary infarction. A VA-sparing procedure, such as flow diversion by stenting, is an alternative treatment in the future, if this approach is demonstrated to effectively prevent rebleeding.

Spontaneous symptomatic intracranial vertebrobasilar dissection: initial and follow-up imaging findings

PURPOSE

To evaluate initial radiologic findings of symptomatic intracranial vertebrobasilar dissections (VBDs) as well as the results at follow-up imaging of dissections that are conservatively managed.

MATERIALS AND METHODS

The respective institutional review boards approved this retrospective study and waived the need for informed consent. The initial radiologic findings of 210 patients with 230 symptomatic intracranial VBDs were retrospectively evaluated (48 ruptured, 182 unruptured). Those patients had undergone conventional angiography as well as magnetic resonance imaging and/or computed tomographic angiography, so that angiographic shapes and pathognomonic findings (eg, intramural hematoma, intimal flap) could be reviewed. The primary angiographic shapes of the symptomatic intracranial VBDs were subdivided into three groups: (a) dilatation without stenosis, (b) pearl-and-string, and (c) stenosis without dilatation. Furthermore, the radiologic evolution of conservatively managed symptomatic intracranial VBDs was evaluated. The respective frequencies of the radiologic findings at initial and follow-up imaging studies were compared by using χ2 tests.

RESULTS

Primary shape differed significantly between ruptured and unruptured symptomatic intracranial VBDs. Most ruptured dissections presented with one of two main structures: dilatation without stenosis or pearl-and-string appearance. The primary shape of unruptured dissections was evenly distributed among the three types of findings. Intramural hematomas were most frequently found in the stenosis-without-dilatation group (42 of 60 [70%]), followed by the pearl-and-string group (27 of 90 [30%]). Intimal flap was most frequently found in the pearl-and-string group (21 of 90 [23%]), followed by the stenosis-without-dilatation group (eight of 60 [13%]). Follow-up results significantly differed by initial VBD shapes: Seventy-four percent (25 of 34) of the dilatation-without-stenosis group showed no change, whereas improvement was observed in 91% (39 of 43) of the stenosis-without-dilatation group (P<.05). Intracranial VBDs with intramural hematoma showed improvement in 63% (34 of 54) of cases, progression occurred in 20% (11 of 54), and only 17% (nine of 54) exhibited no change (P<.05).

CONCLUSION

Primary angiographic shapes of symptomatic intracranial VBDs differed between ruptured and unruptured lesions. The stenosis-without-dilatation lesions most frequently exhibited radiologic improvement at follow-up imaging, followed by pearl-and-string and dilatation-without-stenosis lesions.

Intracranial dissection: incidence and long term endovascular treatment results of a not so rare disease

OBJECTIVE

The objective of this communication was to study the incidence and course of ICD and the long term outcome of this severe disease. The second goal was to analyze the different endovascular treatment modalities according to their long term results.

METHODS

It is a retrospective analysis of 14 patients with ICD admitted in a single center in two consecutive years, treated with endovascular procedures. Patients harbouring blister-like ruptured intracranial aneurysms were excluded from this study.

RESULTS

In this case series, 12 patients presented with subarachnoid hemorrhage (SAH) and 2 with brain stem symptoms. Mean age was 51 years and 13 patients were female. Six patients (43%) died and 8 (57%) survived with a mRS at 0-1. Mean follow up was 21 months.

CONCLUSIONS

ICD as a cause of SAH seems to be more frequent than previously thought and usually has a severe course. It requires a high level of suspicion to diagnosis and specific endovascular treatment modalities are required for each location to ensure long term stability and change the poor prognosis.

Treatment of Spontaneous Intradural Vertebral Artery Dissections

Spontaneous intradural vertebral artery dissections may cause subarachnoid hemorrhage and often result in devastating damage. Increased use of noninvasive imaging studies has allowed larger numbers of patients to be diagnosed. In addition, intracranial vertebral artery dissection tends to induce multiple lesions affecting both intracranial vertebral arteries recurrently. Although unruptured dissections in this area usually have a benign nature, some authors have reported on the incidence of rupture from this lesion. Once hemorrhage from a dissecting vessel wall has occurred, it needs to be treated in the acute phase because of the high risk of rebleeding resulting in high morbidity and mortality. From December 2004 to July 2010, we managed 47 patients with spontaneous vertebral artery dissection, 31 patients were ruptured and 16 were unruptured. All patients who suffered from subarachnoid hemorrhage were treated with endovascular procedures. Most of the patients with unruptured dissection received medical therapy, but if the aneurysmal dilatation persisted or grew, surgical interventions were performed. Stenting with or without coils was deployed for 13 patients with posterior inferior cerebellar artery involvement at the site of dissection and/or were affected on the dominant side. In some patients, stenting was performed even if they were in the acute phase. For other ruptured patients, internal coil trappings were performed. Six patients died due to severe initial subarachnoid hemorrhage and one patient, who underwent stent deployment with coils for the dominant vertebral artery, with bilateral dissection continuing to the basilar artery died due to rerupture while the next additional coiling was planning. There were two cases of complications related to the intervention. During the follow-up period no bleeding occurred in any of the patients except for the previously mentioned patient. In conclusion, internal coil trapping or stent placement with or without coils was effective in preventing rebleeding of ruptured vertebral artery dissection. If the dissection is unruptured, it is necessary to detect the risk of bleeding with careful watching and when progress appears to be made, patients should be treated promptly. Stent-assisted therapy for preserving the patency of the parent artery and major branches is a promising treatment for vertebral artery dissection, even in the acute stage of subarachnoid hemorrhage. However, the risk of acute rerupture and recurrence remains even with the porous stent placement with or without coils.

Comparison of clinical characteristics and MR angiography appearance in patients with spontaneous intradural vertebral artery dissection with or without subarachnoid hemorrhage

Object

It is well known that spontaneous intradural vertebral artery dissection (siVAD) is an important cause of nontraumatic subarachnoid hemorrhage (SAH). The factors that influence whether SAH develops, however, remain unclear. The aim of this study was to investigate whether clinical characteristics and imaging findings are different in patients with siVAD with SAH compared to those with siVAD without SAH.

Methods

The authors conducted a retrospective, single-institution study involving patients in whom siVAD developed with or without SAH, between July 2003 and November 2010. Univariate and multivariate analyses were performed to evaluate clinical characteristics and MR angiography findings. The vertebral-union-basilar angle (VUBA) was defined as the most acute angle between line of the basilar artery trunk and line of the vertebral angle (VA) at the vertebral union on 3D MR angiograms.

Results

Among 58 patients with siVAD, 21 developed SAH. The presence of siVAD and SAH was significantly associated with higher rates of current smoking (OR 13; 95% CI 3.6–38; p < 0.0001), dissection of the dominant VA (OR 9.2; 95% CI 2.5–19; p = 0.0004), and unruptured supratentorial nondissecting saccular aneurysms (OR 11; 95% CI 2.1–19; p = 0.0025), and the VUBA of the dominant VA was significantly larger (p < 0.0001, univariate analysis). Multivariate analysis showed that these differences were still significant (p < 0.05).

Conclusions

A larger VUBA of the dominant VA, the presence of unruptured supratentorial nondissecting saccular aneurysms, and current smoking may be factors that predict which patients with siVAD will develop SAH by dominant VAD.

Strategy for Treating Unruptured Vertebral Artery Dissecting Aneurysms

BACKGROUND

The natural course of unruptured vertebral artery dissecting aneurysms (VADAs) remains unclear.

OBJECTIVE

The purpose of this retrospective study was to develop a strategy for treating unruptured VADAs based on long-term follow-up.

METHODS

Our study population consisted of 100 patients with unruptured VADAs; in 66, the initial symptom was headache only, 30 presented with ischemic symptoms and 4 with mass effect. All underwent magnetic resonance imaging and magnetic resonance angiography at the time of admission and 2 weeks and 1, 3, 6, 12, and 24 months after the onset. If the dissection site was demonstrated to be enlarged on magnetic resonance imaging and magnetic resonance angiography without the manifestation of new symptoms, the patients received additional treatment to prevent bleeding.

RESULTS

Of the 100 patients, 4 underwent early intervention because of symptom exacerbation. The other 96 were initially treated conservatively; during follow-up, 5 manifested lesion enlargement on magnetic resonance angiography. Nine patients received additional treatment; 1 underwent direct surgery with trapping of the dissection site, and 8 underwent coil embolization. The other 91 patients continued to be treated conservatively; the dissection site remained unchanged in 70, improved or healed in 18, and disappeared in 3 patients. We treated 38 patients with recurrent ischemic attacks with antiplatelet therapy. No patients experienced bleeding or permanent neurological deficits during follow-up.

CONCLUSION

The nature of an unruptured VADA is not highly aggressive. However, if the dissection site enlarges without the manifestation of new symptoms, it should be occluded. In patients with recurrent ischemic attacks antiplatelet therapy should be considered.

Natural course of intracranial arterial dissections

Object

Noninvasive neuroimaging techniques are increasingly identifying unruptured intracranial arterial dissections (IADs) at examination for headache or ischemic symptoms. Approximately 3% of cases of aneurysmal subarachnoid hemorrhage (SAH) are caused by IADs in Japan, but the natural history of unruptured IADs is not known.

Methods

Clinical data obtained in 190 patients with 206 IADs were retrospectively analyzed on the basis of long-time follow-up of geometry and clinical event. The IADs were divided into an unruptured group and SAH group depending on the patient's clinical status at the initial diagnosis. Day 0 was defined as the day preceding diagnosis of IAD—that is, the day of symptom onset. This was retrospectively determined from the clinical history.

Results

The 206 IADs included 98 unruptured lesions and 108 SAH. In both groups, the vertebral artery was the most frequent site. In the unruptured group, 93 IADs were followed for a mean of 3.44 years. The mean interval between symptom onset (Day 0) and neuroimaging diagnosis was 9.8 days. Subsequent geometry change was seen in 78 (83.9%) of 93 IADs. Major change was almost completed within 2 months, and complete normalization was seen on neuroimaging in 17 (18.3%) of 93 IADs, with the earliest on Day 15. Rupture of the IAD in the unruptured group occurred in only 1 patient on Day 11.

In the SAH group, 84 of the 108 patients complained of preceding headache before onset of SAH. In 81 (96.4%) of the 84 patients, SAH occurred on Day 0–3 with the latest on Day 11. In all patients in the unruptured and SAH groups, the latest day of SAH from the onset of preceding headache was Day 11.

Conclusions

Most IADs causing SAH bleed within a few days of occurrence. Most IADs that are unruptured already have little risk for bleeding at diagnosis because of the repair process. Intracranial arterial dissections may be much more common than previously thought, and the majority may occur and heal without symptom manifestation.

Cerebrovascular Dissections—A Review Part I: Spontaneous Dissections

Spontaneous cerebrovascular dissections are subintimal or subadventitial cervical carotid and vertebral artery wall injuries and are the cause of as many as 2% of all ischemic strokes. Spontaneous dissections are the leading cause of stroke in patients younger than 45 years of age, accounting for almost one fourth of strokes in this population. A history of some degree of trivial trauma is present in nearly one fourth of cases. Subsequent mortality or neurological morbidity is usually the result of distal ischemia produced by emboli released from the injury site, although local mass effect produced by arterial dilation or aneurysm formation also can occur. The gold standard for diagnosis remains digital subtraction angiography. Computed tomography angiography, magnetic resonance angiography, and ultrasonography are complementary means o evaluation, particularly for injury screening or treatment follow-up. The annual rate of stroke after injury is approximately 1% or less per year. The currently accepted method of therapy remains antithrombotic medication, either in the form of anticoagulation or antiplatelet agents; however, no class I medical evidence exists to guide therapy. Other options for treatment include thrombolysis and endovascular therapy, although the efficacy and indications for these methods remain unclear.

Differential diagnosis between traumatic and nontraumatic rupture of the intracranial vertebral artery in medicolegal autopsy

We attempted to establish histopathological identification between traumatic rupture and nontraumatic arterial dissection of the intracranial vertebral artery (IVA) resulting in subarachnoid hemorrhage (SAH). Step-serial observations of ruptured IVAs among four traumatic and 44 nontraumatic SAH patients were investigated. We found that the most specific characteristic for differentiation was the shape of the ruptured adventitia. Extension of the adventitia was clearly observed in nontraumatic cases. In contrast, traumatic cases showed transmural ruptures. Other specific characteristics were also detected. For traumatic cases, small incomplete tears of intima and media were frequently found; they formed oblique tears without adventitial extension. Fragmentized internal elastic lamina was also observed in traumatic cases. In contrast, previous arterial dissections were frequently confirmed in nontraumatic cases. Medial degenerations or defects were detected in all nontraumatic cases. In these cases, the peripheral lesion of the rupture was appeared as intimal tears at recessed vascular wall caused by medial defects. This suggested a relationship between medial lesions and pathogenesis of arterial dissections. These additional features were found in both ruptured and non-ruptured intracranial arteries. We concluded that histopathological investigation is a reliable method for differential diagnosis between traumatic and nontraumatic rupture of the IVA resulting in fatal SAH. These morphological differentiations could be valuable for medicolegal diagnosis.