Differences in Vertebrobasilar Artery Morphology between Spontaneous Intradural Vertebral Artery Dissections with and without Subarachnoid Hemorrhage

Abstract

Background: Patients with spontaneous intradural vertebral artery dissection (siVAD) developing subarachnoid hemorrhage (SAH) have been observed to have poor outcomes. Factors predisposing siVAD patients to SAH are not well known. We aimed to investigate the clinical and vertebrobasilar artery morphological characteristics associated with SAH in patients with siVAD. Methods: We reviewed 103 consecutive patients with siVAD managed at our facility between July 2003 and June 2012. We divided the patients into groups, with (n = 22) and without (n = 81) SAH, and compared clinical and vertebrobasilar artery morphological characteristics between them. The vertebral-union-basilar angle (VUBA) was defined as the most acute angle between the line of the basilar artery trunk and the line of the vertebral artery at the vertebral union on 3-dimensional magnetic resonance angiography, computed tomographic angiography, or digital subtraction angiography. ‘Steep vertebral artery’ was defined as VUBA >45°. Basilar artery bending was defined as the longest distance from the line which connected the basilar top and vertebral artery union to the greatest bending point of the basilar artery. Results: Stepwise logistic regression analysis was performed using variables that were marginally or significantly associated with SAH on univariate analysis (p < 0.10) and that were thought to be clinically important for SAH. It showed SAH patients to have significantly higher proportions of current smoking (OR: 7.7; 95% CI: 2.7–22; p = 0.0015), dissection of the dominant vertebral artery (OR: 4.9; 95% CI: 1.8–13; p = 0.043), steep vertebral artery of the dissecting side (OR: 7.2; 95% CI: 2.6–20; p = 0.0023), posterior inferior cerebellar artery involvement (OR: 4.0; 95% CI: 1.3–13; p = 0.011), basilar artery bending <3 mm (OR: 3.4; 95% CI: 1.3–9.5; p = 0.0040), and pearl-and-string sign (OR: 5.7; 95% CI: 2.0–16; p = 0.0033). Conclusions: We suggest that the clinical and vertebrobasilar artery morphological characteristics demonstrated in the present study may be related to SAH induced by siVAD. Although all patients with siVAD should be closely monitored, those with siVAD who have these characteristics should perhaps be more closely followed than those who do not have such features.

Basilar Artery Angulation in Association with Aging and Pontine Lacunar Infarction: A Multicenter Observational Study

“…Hence, the present method is effective for measuring the degree of angulation of the BA quantitatively. Previous methods for analyzing BA geometry were largely dependent on 2D axial images (XY sections only) 25,26) or maximum intensity projection (MIP) images 9,16,27) . However, the geometry of the BA cannot be measured appropriately using previous conventional methods for the following reasons: 1) the reference points frequently overlap and are obscured, and 2) the BA angles and distances are measured on randomly projected images, especially when using MIP images.…”

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

“…16,44 The relative frequency of intracranial artery dissections in the diff erent intracranial segments varies between studies (table 1; appendix), but in most series the vertebral artery (intradural portion [V4 segment]) is the most common site. Bilateral intracranial artery dissection seems to happen less often than bilateral cervical artery dissection does (<11% in most intracranial artery dissection series 21,30,32,34 vs 15% in cervical artery dissection series 11,17,45 ), with bilateral intracranial artery dissection mostly reported in the V4 segment.…”

“…Recurrent bleeding was reported in 0-11% of patients with intracranial artery dissection with subarachnoid haemorrhage after surgical or endovascular treatment, and after treatment for ischaemia in 0-22% of patients. 19,[21][22][23][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] Cranial nerve palsies and spinal cord infarctions were seldom reported. 35,41,93 Overall, of 813 endovascular procedures, 50 (6•2%) cerebral or spinal cord ischaemia, 15 (1•8%) rupture and rebleeding, and seven (0•9%) cases of cranial nerve palsies were reported; of 125 surgical procedures, 23 (18•4%) cerebral or spinal cord ischaemia, one (0•8%) rupture and rebleeding, and one (0•8%) case of cranial nerve palsy were reported.…”

“…Overall, more than 79% of patients with intracranial artery dissection and without subarachnoid haemor rhage had a favourable functional outcome (modifi ed Rankin Scale ≤1 or ≤2, or equivalent). 19,[21][22][23][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] One study 21 showed that …”

Basilar extension and posterior inferior cerebellar artery involvement as risk factors for progression of the unruptured spontaneous intradural vertebral artery dissection

“…Our recent studies showed that some vertebrobasilar morphologies might have an influence on siVAD-induced subarachnoid haemorrhage 8 9. We hypothesised that vertebrobasilar morphologies might also be markers for unruptured siVAD instability, leading to the signs of siVAD progression, including siVAD-induced stroke or worsening of aneurysmal dilatation and stenotic occlusive changes.…”