Annals of Indian Academy of Neurology
EDITORIAL COMMENTARY
Year
: 2020  |  Volume : 23  |  Issue : 3  |  Page : 245-

Perplexing perspectives of ICAD


M. V. P. Srivastava 
 Department of Neurology, Neurosciences Center, AIIMS, New Delhi, India

Correspondence Address:
Dr. M. V. P. Srivastava
Department of Neurology, Neurosciences Center, AIIMS, New Delhi
India




How to cite this article:
Srivastava MV. Perplexing perspectives of ICAD.Ann Indian Acad Neurol 2020;23:245-245


How to cite this URL:
Srivastava MV. Perplexing perspectives of ICAD. Ann Indian Acad Neurol [serial online] 2020 [cited 2020 Jul 12 ];23:245-245
Available from: http://www.annalsofian.org/text.asp?2020/23/3/245/286052


Full Text



Intracranial atherosclerotic disease (ICAD) is the most common mechanism of ischemic stroke worldwide accounting for 30%-50% of strokes amongst Asians[1] and 8%-10% of strokes in Caucasians.[2] The described associations for ICAD in susceptible populations include race,[3] genes,[4] and vascular risk factors.[5] The mechanisms proposed in ischemia include artery-to-artery embolism, local branch occlusion, hemodynamic compromise resulting from progressive arterial narrowing or a combination of these factors.[6]

Why is ICAD more prevalent in Asians than that in Westerners; the reason for this is not completely known. Possible explanations include inherited susceptibility of intracranial vessels to atherosclerosis, acquired differences in the prevalence of risk factors and differential responses to the same risk factors. Lifestyle may play a role in racial–ethnic differences.[7]

Saraf et al. published a very important study in the current journal from South India comparing the data of stroke patients with ICAD between two major regional cohorts of South Indian and Chicago, USA.

Surprisingly in the current study, more patients with ICAD were recruited from Chicago in the defined time period contrary to the expectation of a higher number of ICAD patients from India, given the difference in the prevalence of ICAD between the regions.

The other demographic, clinical, and outcome parameters between the two cohorts were all as expected according to the published literature and add valuable data to understand the differences.

The stroke recurrence in the three-month outcome assessment, was more in Chicago cohort (21.7% vs 1.7%), and although a more rampant use of DUAT in South India cohort may explain the difference, more reasons need to be explored. Although ICAD is more sinister in terms of stroke recurrence, the extremely high rate of recurrent stroke in the Chicago cohort at 3 months (21.7%), assuming a better vascular risk factor control, compliance, follow-up, and stroke care pathways in the developed nation (Chicago cohort), looks unnerving!

This finding is even more surprising, given the recurrence rate of stroke from ICAD published in more recent trials (SAMMPRIS, 2011: 12.2% and TOSS-2, 2011: 4.4-6.5%).

The published risk factors for stroke recurrence amongst symptomatic ICAD include systolic blood pressure ≥140 mm Hg, cholesterol ≥200 mg/dl, metabolic syndrome, severity of stenosis ≥70%, poor collaterals, and black race.[6],[7] Hence, assuming that in Chicago cohort the risk factors are well controlled and severity of stenosis was comparable in both regions, the reasons why the Chicago cohort sported a stroke recurrence of 21% remains enigmatically abstruse!

Overall, the study has a very important value addition for understanding and managing ICAD across two geographically, economically, and possibly ethnically different populations.

References

1Wong LK. Global burden of intracranial atherosclerosis. Int J Stroke 2006;1:158-9.
2Gorelick PB, Wong KS, Bae HJ, Pandey DK. Large artery intracranial occlusive disease: A large worldwide burden but a relatively neglected frontier. Stroke 2008; 39:2396-9.
3Sacco RL, Kargman D, Gu Q, Zamanillo MC. Race, ethnicity and determinants of intracranial atherosclerotic cerebral infarction: The Northern Manhattan Stroke Study. Stroke 1995;26:14-20.
4Uehara T, Tabuchi T, Hayashi H, Kurogane H, Yamadori A. Asymptomatic occlusive lesions of carotid and intracranial arteries in Japanese patients with ischemic heart disease: Evaluation by brain magnetic resonance angiography. Stroke 1996;27:393-7.
5Wong KS, Gao S, Chan YL, Hansberg T, Lam WW, Droste DW, et al. Mechanisms of acute cerebral infarctions in patients with middle cerebral artery stenosis: A diffusion-weighted imaging and microemboli monitoring study. Ann Neurol 2002;52:74-81.
6Bang OY, Saver JL, Liebeskind DS, Pineda S, Yun SW, Ovbiagele B. Impact of metabolic syndrome on distribution of cervicocephalic atherosclerosis: Data from a diverse race-ethnic group. J Neurol Sci 2009;284:40-5.
7Qureshi AI, Feldmann E, Gomez CR, Johnston SC, Kasner SE, Quick DC, et al. Intracranial atherosclerotic disease: An up date. Ann Neurol 2009;66:730-8.