Pathogenesis of spontaneous cervico-cerebral artery dissection. A hypothesis and a review of the literature

Unraveling the Links between Chronic Inflammation, Autoimmunity, and Spontaneous Cervicocranial Arterial Dissection

Advances in imaging techniques have led to a rise in the diagnosis of spontaneous cervicocranial arterial dissection (SCCAD), which is now considered a common cause of stroke in young adults. However, our understanding of the pathophysiological mechanisms underlying SCCAD remains limited. Prior studies have proposed various factors contributing to arterial wall weakness or stress as potential causes for SCCAD. A combination of biopsies, case reports, and case-control studies suggests that inflammatory changes and autoimmunity may play roles in the cascade of events leading to SCCAD. In this review, we examine the close relationship between SCCAD, chronic inflammation, and autoimmune diseases, aiming to explore potential underlying pathophysiological mechanisms connecting these conditions. While some relevant hypotheses and studies exist, direct evidence on this topic is still relatively scarce. Further investigation of the underlying mechanisms in larger clinical cohorts is needed, and the exploration of animal models may provide novel insights.

Association between carotid artery dissection and vascular tortuosity: a case-control study

PURPOSE

We aimed to verify if vascular tortuosity (VT) may represent a risk factor for spontaneous epiaortic vessel dissection (sEVD) in young adult patients.

METHODS

We identified 304 patients aged under 55 years consecutively admitted for acute cerebrovascular events to our Stroke Unit. After checking the possibility to perform a 3D reconstruction of epiaortic vessels on CT-angiography images, we selected and compared fifty patients with sEVD (cases) with fifty-one patients without dissection (controls). VT of carotid and vertebral arteries was measured on reconstructions evaluating the vascular tortuosity index (VTI), calculated according to a specific algorithm, and the presence of kinking and coiling. Differences between groups were analyzed by Student-t test for numeric variables and chi-square test for categoric ones. A ROC curve analysis was used to look for a VTI threshold value beyond which the risk of dissection was significantly increased.

RESULTS

VTI was significantly higher in cases than in controls only considering carotid arteries (p = 0.029); cases did not have a significantly higher rate of kinking and coiling than controls (p = 0.059 and 0.077, respectively). We have found a significant VTI threshold value of 27.9% (under curve area = 61.6%, p = 0.04) only for carotid artery dissection.

CONCLUSION

VT appears to be associated with an increased risk of dissection for the carotid district but not for the vertebral one. The different structure, embryogenesis, and pathophysiology of dissection between the two districts could explain this finding. VTI threshold as carotid artery dissection predictor deserves confirmation in larger studies.

Arterial Dissection in Antiphospholipid Syndrome Patients: Two Case Reports and a Literature Review

Antiphospholipid syndrome (APS) is a multisystemic autoimmune disease which presents with thromboembolic disease, pregnancy complications and the presence of antiphospholipid antibodies. There are some reports of arterial dissections in different sites of the body associated with APS. We describe two patients with APS who developed ischaemic stroke as a result of vertebral artery dissection in the absence of acquired and genetic risk factors for arterial dissection. We also conducted a systematic review of the literature for cases of arterial dissection associated with APS. We suspect that APS may be a potential cause of vasculopathy and arterial dissection. Further research is needed to explore this possible association.

LEARNING POINTS

Antiphospholipid syndrome (APS) is a major risk factor for stroke in young patients.APS may be associated with vasculopathy and arterial dissection.Patients should meet both clinical and laboratory criteria for a diagnosis of APS.

An atypical case of Stanford type-A chronic aortic dissection managed conservatively

Stanford type-A aortic dissection is a clinical emergency; mortality is high, and surgery is urgently required in most cases. Chronic forms of type-A dissection are rare and have a poor prognosis if not treated surgically. We present an unusual case of chronic type-A aortic dissection, with silent onset, in an oncologic patient without risk factors, which was managed conservatively and remained substantially stable during follow-up.

M2 segment dissection of middle cerebral artery diagnosed using high-resolution magnetic resonance imaging

Middle cerebral artery (MCA) dissection is a rare cause of ischemic stroke, especially in the M2 or M3 segments. Diagnosis of intracranial artery dissection remains challenging. We herein report a case of M2 segment dissection of the MCA with typical features of an intimal flap and intramural hematoma diagnosed using high-resolution 3T magnetic resonance imaging. This imaging technique might be a more effective noninvasive method by which to diagnose M2 segment dissection of the MCA than either computed tomography angiography or digital subtraction angiography.

Rupture of the spleen or splenic vessels (splenic emergency syndrome) in late pregnancy: a report of two autopsy cases

Emergencies of splenic origin in pregnancy involving rupture of the splenic artery or hemorrhage are rare events that can present suddenly and unexpectedly. We report two cases of young women, both in the third trimester of gestation, who suffered sudden malaise while at home and were admitted to the ER. On arrival, both were in severe hemorrhagic shock due to gross hemoperitoneum and they died in the operating theatre during emergency surgery. To better clarify the causes and sequence of these mortalities, forensic autopsy was requested in each case. In the first (a 26-year-old primigravida in the 40th week of pregnancy), cadaveric section demonstrated the rupture of an aneurysm of the splenic artery. In the second (a 28-year-old multipara in the 33rd week of pregnancy), the clinical and anatomopathological data suggested splenic hemorrhage. In both cases histology showed a fibrodysplasia of the arterial wall involving the splenic artery in one case and the hilar branches in the other. In agreement with the data in literature, in such cases particular importance must be attributed to examination of the arterial wall. In pregnancy a synergic effect between hemodynamic and endocrine factors can cause degeneration of the arteries resulting in dramatic hemorrhage. From the forensic pathologist's viewpoint, these cases underline the importance of histopathological study of the splenic artery in the interpretation of the pathogenesis of splenic vessel rupture or hemorrhage.

[Cardiac tamponade due to rupture of healed and sealed aortic intimomedial tear--case report]

INTRODUCTION

The healed and sealed intimomedial aortic tears showed clearly defined edges and U-shaped defect of the tissue extending from intima into the media of a varying depth, filled by paler tissue with smooth surface. These tears can be solitary or multilocular, localized in different parts of the aorta, followed by limited intramural incomplete dissection. They can be provoked by diseases or injury. This part of the aortic wall filled with scar tissue is very vulnerable and could be the site of new rupture, followed by tamponade or fatal internal bleeding.

CASE OUTLINE

In this paper, we report a case of unexpected unknown death of a young male, 26-years-old, found on the ground, near his car. At autopsy, we established the old healed and open intimomedial tear on the posterior wall of the ascending aorta, with a remaining little dissection flap. This part of the wall with scar tissue was ruptured, causing bleeding in the pericardial sac, and tamponade. Histologically, the early stage of cystic medial degeneration was recognized. There were no injuries of the skin, soft tissue and bones.

CONCLUSION

In the paper, we discussed the manner of death in this case, as well as the medicolegal implications.

Management of spontaneous haemorrhagic intracranial vertebrobasilar dissection: review of 21 consecutive cases

INTRODUCTION

Haemorrhagic intracranial vertebrobasilar dissection is an uncommon cause of nontraumatic subarachnoid haemorrhage (SAH) and accounts for only 1-10% of non-traumatic SAH. Treatment in the acute phase is considered to be essential because of the high risk of rebleeding and the consequent unfavourable outcome. However, the location, the potential for involvement of eloquent vessels and the histopathological characteristics of the vessel wall make treatment demanding from both a technical and anatomical point of view. We report our experience in the management of this disease. PATIENTS AND TREATMENTS: From 1989 to June 2006, we managed 21 patients with spontaneous haemorrhagic dissection located in the intracranial vertebrobasilar system, 13 patients were treated using an endovascular approach, 1 by surgical clipping, and 7 were managed conservatively.

RESULTS

Among the 13 patients treated endovascularly, 7 underwent proximal occlusion, 4 underwent parent artery embolization at the site of dissection, and 2 underwent endovascular trapping. Severe, treatment-related complications due to dislodgement of the thrombus during the procedure occurred in 1 patient, who then died from brainstem ischaemia. One patient died from severe pneumonia and one patient was left disabled from vasospastic ischaemia resulting from severe initial SAH. The remaining 10 patients had satisfactory outcomes: none rebled after treatment and when discharged they had Karnovsky scores of 80-100. Of the 7 conservatively treated patients, three died of rebleeding and four were discharged with Karnovsky scores of 50-100. One patient, who was treated surgically, was discharged with a Karnovsky of 90.

CONCLUSION

The high rate of rebleeding and consequent mortality among the patients treated conservatively argues for treatment in the acute phase. Treatment should be guided by each patient's angiomorphology, clinical condition and the experience of the neurosurgical/neuroradiological team. Options include endovascular or surgical trapping of the dissection and proximal occlusion and embolisation of the parent artery at the site of the dissection.

Spontaneous mirror dissections of cervicocephalic arteries. Pathomechanical considerations

SUMMARY

While so-called twin or mirror aneurysms constitute an established subgroup of multiple aneurysms, simultaneous spontaneous mirror dissections of cervicocephalic artery have not yet been reported as a particular entity. Among the patients treated at our institution since 1989, we identified 74 patients with spontaneous, nontraumatic dissections. Six of these cases presented with simultaneous bilateral dissections and four of the six patients had mirror dissections. Acute or chronic headache was present in all four cases. Additional clinical presentations consisted of impaired consciousness, cranial nerve palsy, and tinnitus. Angiography revealed irregular stenosis, dilatation or aneurysms located in the cervical ICA (internal carotid artery), VA (vertebral artery), or MCA (middle cerebral artery) without evident location bias. Although mirror dissections seems to be an exceptional finding, they may shed light on the vulnerability of different arterial segments to specific diseases. Similar to arterial aneurysm formation, pathogenesis of mirror dissection may involve an underlying "shared defect" in the endothelial cells, since these cells demonstrate a bilateral distribution during embryological development. This particular distribution therefore also provides a chronicle trail of the first trigger striking during embryonic development and demonstrates the segmental vulnerability to highly specific triggers.