Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 58, Num. 5, 2010, pp. 810-812

Neurology India, Vol. 58, No. 5, September-October, 2010, pp. 810-812

Letter to Editor

Vertebrobasilar dolichoectasia and a tale of two brothers

Deepak Gupta¹, Uttam B George², Jeyaraj D Pandian³

¹ Department of Neurology, Ludhiana Mediciti Hospital, Ludhiana, Punjab - 142 027, India
² Department of Radiodiagnosis, Christian Medical College and Hospital, Ludhiana, Punjab - 141 008, India
³ Department of Neurology, Christian Medical College and Hospital, Ludhiana, Punjab - 141 008, India

Correspondence Address:
Deepak Gupta
Department of Neurology, Ludhiana Mediciti Hospital, Ludhiana, Punjab - 142 027
India
dg14_9@rediffmail.com

Date of Acceptance: 30-Jul-2010

Code Number: ni10232

PMID: 21045530

DOI: 10.4103/0028-3886.72199

Sir,

Vertebrobasilar dolichoectasia (VBD) is characterized by marked elongation, dilatation and tortuosity of the vertebral and the basilar arteries. The mean diameter of the normal basilar artery (BA) is 3.17 mm at the level of the pons, and the bifurcation is located in the interpeduncular cistern adjacent to the dorsum sellae or in the suprasellar cistern below the level of the floor of the third ventricle. ^[1] BA is considered dolichoectatic if at any point along its course it lies lateral to the margin of the clivus or dorsum sellae or bifurcates above the plane of the suprasellar cistern and if the diameter of the BA is greater than 4.5 mm. ^[2],[3] Although the clinical manifestations of VBD are well known, ^[2],[4] it is unclear whether genetic factors or atherosclerosis is the primary inciting event in its pathogenesis. ^[5],[6] We report occurrence of VBD in two siblings in an attempt to highlight the role of genetic factors in the development of VBD.

Patient 1, a 55-year-old male, diabetic, hypertensive and dyslipidemic, presented with acute onset of slurring of speech and dizziness. Examination revealed only mild dysarthria. Magnetic resonance imaging (MRI) brain with diffusion-weighted imaging (DWI) showed an acute paramedian and right ventral pontine infarct [Figure - 1]. There was a chronic right putaminal infarct also. Time of flight magnetic resonance angiography (TOF MRA) of cranial vessels showed dolichoectasia of the left vertebral artery (VA) and the entire BA till its bifurcation [Figure - 2]. The maximum diameter of BA was 12.7 mm; and of left VA, 11.4 mm. The BA bifurcated above the level of suprasellar cistern. After discharge, he was noncompliant with his antiplatelets and was readmitted six months later with right hemiparesis. DWI did not show any fresh infarcts.

Patient 2, a 67-year-old male, dyslipidemic and elder sibling of patient 1, presented with left hemiparesis and slurring of speech of 3 hours' duration. MRI brain with DWI showed an acute right paramedian pontine infarct [Figure - 3]. In addition, there were chronic infarcts in left paramedian pons, bilateral globus pallidus and centrum semiovale. TOF MRA of cranial vessels showed dolichoectasia of the entire BA and the left VA with normal flow voids [Figure - 2]. The maximum diameter of the BA was 6.9 mm; and of the left VA, 6.4 mm. The BA bifurcated above the level of dorsum sellae. MRA of the anterior circulation, ECG and transthoracic echocardiography were normal in both cases. There was family history of ischemic heart disease in three other siblings, two of whom died due to acute coronary events [Figure - 4].

The occurrence of VBD in the siblings in this report lends support to the hypothesis for possible genetic predisposition in this condition. Dolichoectatic arteries have a thin arterial wall, with prominent degeneration of the internal elastic lamina ^[5] and thinning of the media. A genetic predisposition would thereby involve defects in arterial wall extracellular matrix components, as collagen, elastin, proteoglycans, laminin, etc., thus making these vessels susceptible to dilatation. ^[7] Co-occurrence of intracranial arterial dolichoectasia (IADE) with abdominal aortic aneurysm ^[8] and coronary artery ectesias (CAE) ^[6] is known and would indicate that there is a generalized (genetic) rather than a local (atherosclerosis) cause for the abnormal arterial dilatation. Fernando and colleagues did not find any association between IADE and markers of atherosclerosis. ^[5] Also, there are series where no atherosclerosis was noted in the dolichoectatic vessels. ^[9]

The occurrence of infarcts in relation to VBD ^[2],[3] can also be explained without atherosclerosis. The most common infarcts due to VBD, paramedian pontine infarcts, involve distortion of the branches of BA due to elongation and tortuosity of the BA and hemodynamic factors such as significant reduction of flow velocity in the BA. ^[4] Therefore, atherosclerosis found in the dolichoectatic vessels may be a consequence of disturbed laminar blood flow in the dolichoectatic arteries, rather than its cause. Although we do not know the status of coronary and basilar arteries of the siblings in this family with ischemic heart disease, the co-occurrence of CAE and VBD is well known. ^[5],[6] In both VBD and CAE, thrombotic events can result due to slow blood flow in the dilated arteries.

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