Haemorrhagic transformation of ischaemic stroke in young adults

Background: Frequency, factors associated with, and impact on outcome of haemorrhagic transformation in young adults with ischaemic stroke are unknown.

Methods: Consecutive young patients (age 15-49) with first-ever ischaemic stroke were included, having their first brain computed tomography/magnetic resonance imaging within seven-days of stroke onset, and second within seven-days from the first imaging. Haemorrhagic transformation in any imaging was classified as haemorrhagic infarct or parenchymal haemorrhage within or remote from the infarct. Symptomatic haemorrhagic transformation was defined according to the European Cooperative Acute Stroke Study II (ECASS II) criteria as any haemorrhage leading to a National Institutes of Health Stroke Scale score increase of ≥4 points or death. Unfavourable three-month outcome was defined as a modified Rankin Scale 2-6.

Results: In 636 eligible patients, any haemorrhagic transformation occurred in 79 patients (12·4%; 10·0-15·2%): 66 (10·4%; 8·24-12·9%) had haemorrhagic infarct, and 13 (2·04%; 1·19-3·46%) had parenchymal haemorrhage. Symptomatic haemorrhagic transformation occurred in 16 patients (2·5%; 4·04-1·55%). In logistic regression analysis, independent factors associated with haemorrhagic transformation were large anterior (18·70; 6·72-52·04), large posterior (9·41; 3·13-28·25), medium-sized (odds ratio 3·30; 95% confidence interval 1·14-9·57) lesions, higher low-density lipoprotein level (1·44 per unit increment; 1·10-1·90), and lower platelet count (1·005 per unit decrement; 1·009-1·001). Haemorrhagic infarct (1·76; 0·76-4·11) or parenchymal haemorrhage (2·39; 0·23-24·76) were not associated with unfavourable functional outcome or death at three-months.

Conclusions: In young adults, haemorrhagic transformation of ischaemic stroke occurred in comparable rates to haemorrhagic transformation in elderly patients. Although haemorrhagic transformation was more common in severe strokes, it was the lesion size and baseline stroke severity that were associated with three-month clinical outcome, not haemorrhagic transformation per se.