Stroke subtypes

Evans A, Perez I, Yu G, Kalra L. Should stroke subtype influence anticoagulation decisions to prevent recurrence in stroke patients with atrial flbrillation Stroke 2001 32 2828-2832. 

Small vessel/lacunar strokes have better short- and long-term (1-year) survival as compared to other stroke subtypes. In the NINDS trial of rt-PA within 3 hours of onset, patients classified as small vessel stroke on the basis of their clinical syndrome had a 50% chance of a normal NIHSS score at 3 months if they received placebo, increasing to 70% in the treatment group. In the Lausanne cohort, 95% were independent after their first event, as opposed to only 65% of the cardioembolic strokes and 49% with large vessel atherothrombotic infarctions. Eighty-two percent of patients with small vessel stroke were independent at 1 year. Even at the time of maximal deficit, between 38% and 64% of small vessel/lacunar patients were independent, with motor impairment and extent of white matter disease adversely affecting outcomes. " In TOAST, small vessel/lacunar stroke was the only subtype associated with a favorable outcome, independent of the NIHSS score. ... 

Since functional outcome and risk of recurrent stroke are, in part, predictable based on the pathophysiologic subtype of stroke, the ability to accurately classify patients based on emergency clinical and imaging data would provide valuable predictive information. Unfortunately, misclassifications of stroke subtypes based on clinical data and a noncontrast CT scan are common. The final subtyping of stroke is made with all available clinical data, but is heavily influenced by neuroimaging studies that identify the location, size, and vascular distribution of the infarct, or that establish that the arteries supplying the region of stroke are stenotic or occluded. 

Brainin M, Seiser A, Czvitkovits B, Pauly E. Stroke subtype is an age-independent predictor of first-year survival. Neuroepidemiology 1992 11(6) 190-195. 

Madden KP, Karanjia PN, Adams HP, Clarke WR. Accuracy in initial stroke subtype diagnosis in the TOAST study. Nuerology 1995 45 1975-1979. 

Bogousslavsky J, RegU F, Besson G, Melo TP, Nater B. Early clinical diagnosis of stroke subtype. Cerebrovasc Dis 1993 3 39 t4. 

Petty GW, Brown Jr. RD, Whisnant JP, Sicks JD, O Fallon WM, Wiebers DO. Ischemic stroke subtypes a population-based study of functional outcome, survival, and recurrence. Stroke 2000 31 1062-1068. 

Chaturvedi S, Adams HP Jr, Woolson RF (1999) Circadian variation in ischemic stroke subtypes. Stroke 30 1792-1795... 

While physicians may not recognize up to 80% of lacunes (Tuszynski et al. 1989), several clinical syndromes have been correlated with relevant lacunes detected at subsequent autopsy. Five of these are regarded as the classic lacunar syndromes pure motor hemiparesis, sensorimotor stroke, pure sensory hemiparesis, dysarthria clumsy hand syndrome, and ataxic hemiparesis (Donnan et al. 2002 Fisher 1982 Bamford 2001). Pure motor stroke is the commonest lacunar syndrome in clinical practice, while pure sensory stroke is encountered less frequently. The involvement of the face, arm and leg of one side is the characteristic feature of the first three syndromes while reductions of consciousness, cognitive or visual field defects are absent. Even though lacunar infarcts have been linked to lacunar syndromes, the latter are of course not specific for this stroke subtype and mimicked by cortical infarcts, intracerebral hematomas, and non-vascular causes (Bogousslavsky et al. 1988 Bamford 2001). 

Despite the advances in neuroimaging, the early identification of ischemic stroke subtypes and patterns has several heuristic values, besides academic and research interest. It helps the physician to answer the patient s and their relatives anxieties concerning the risk of early death, disability, stroke... 

Kang DW, Chalela JA, Ezzeddine MA et al (2003a) Association of ischemic lesion patterns on early diffusion-weighted imaging with TOAST stroke subtypes. Arch Neurol 60 1730-1734... 

Indicative stroke subtype Mainly embolic stroke Any subtype... 

The age-standardized death rate attributed to stroke varies six-fold between developed countries while very little is known about the developing world (Inzitari et oL 1995 Connor et al. 2007). Particularly high reported rates of stroke occur in eastern Europe and Japan, and particularly low rates in certain parts of North America and some western European countries (Feigin et al 2003). The reasons for these differences are unclear but one possibility is that the stroke subtypes more likely to be fatal, particularly intracranial hemorrhage or cardioembolic stroke, are more frequent in countries with high stroke mortality. 

There are racial and social differences in susceptibility to stroke and TIA (Forouhi and Satter 2006) and in the incidence of the various stroke subtypes (Fig. 1.4). Some of these racial differences are partly caused by differences in risk factor prevalence hypertension... 

Tunstall-Pedoe H, Kuulasmaa K, Amouyel P et al. (1994). Myocardial infarction and coronary deaths in the World Health Organization MONICA Project. Registration procedures, event rates and case-fatality rates in 38 populations from 21 countries in four continents. Circulation 90 583-612 Wald NJ, Law MR (2003). A strategy to reduce cardiovascular disease by more than 80%. British Medical Journal 326 1419 White H, Boden-Albala B, Wang C et al. (2005). Ischemic stroke subtype incidence among whites, blacks and Hispanics the Northern Manhattan Study. Circulation 111 1327-1331 Wityk RJ, Pessin MS, Kaplan RF et al. (1994). Serial assessment of acute stroke using the NIH Stroke Scale. Stroke 25 362-365. 

Wolfe CDA (2000). The impact of stroke. British Medical Bulletin 56 275-286 Wohe CD, Corbin DO, Smeeton NC et al. (2006a). Estimation of the risk of stroke in black populations in Barbados and South London. Stroke 37 1986-1990 Wohe CD, Corbin DO, Smeeton NC et al. (2006b). Poststroke survival for black-Caribbean populations in Barbados and South London. Stroke 37 1991-1996 Woo D, Gehel J, Miller R et al. (1999). Incidence rates of first-ever ischemic stroke subtypes among blacks a population-based study. Stroke 30 2517-2522... 

Hawkins GC, Bonita R, Broad JB et al. (1995). Inadequacy of clinical scoring systems to differentiate stroke subtypes in population-based studies. Stroke 26 1338-1342 Hjort N, Christensen S, Soiling C et al. (2005a). Ischemic injury detected by diffusion imaging 11 minutes after stroke. Annals of Neurology 58 462-465... 

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