Abstract 10: Perfusion Imaging In Patients Randomised To rt-PA or Control In The Third International Stroke Trial (IST-3): Baseline Characteristics And Association With Outcome.
Aim: Perfusion imaging (PI) may help identify patients with brain at risk of infarction who may benefit most from rt-PA. It remains unclear which perfusion parameter is most specific or if PI should influence decisions for use of rt-PA. IST-3 aimed to improve use of rt-PA.
Methods: IST-3 was a randomised trial of iv rt-PA (0.9mg/kg) <6 hours of acute ischaemic stroke (registration ISRCTN25765518). Pre-randomisation CT or MR PI was performed in some centres. PI data were processed centrally to produce maps of relative (r) CBF; quantitative (q) CBF, CBV, MTT, Tmax. PI images were read centrally, blind, scoring PI lesion extent by ASPECTS and relative to plain CT/MR lesion size (<80%/100%/>120%). All plain CT or MR imaging was assessed, blind, by an expert panel for early infarct signs (site/size of tissue hypodensity, swelling; hyperdense artery; haemorrhage) and background brain changes (atrophy, leukoaraiosis, prior infarct) with validated scales. We assessed baseline characteristics of patients randomised with/without PI in IST-3 and associations with outcome.
Results: 28 IST-3 centres performed PI on 152 patients: 129 were pre-randomisation, 113 were analysable (97 CT, 16 MR). Baseline features were the same in those with as without PI, respectively: 55% v 53% were aged >80; 52% vs 50% had NIHSS ≥11; 35% v 41% with visible infarct signs. PI lesions were smallest for qCBV, largest for qMTT. PI lesions were larger (all parameters) in patients scanned <3 vs 3-6 hours (with more >120% plain scan lesion), aged >80 vs <80, and with higher NIHSS scores. Large qCBV lesions were associated with SICH, early and late death and poor functional outcome. Large lesions on other PI parameters were associated with poor functional outcome.
Conclusion: IST-3 is the largest randomised trial of rt-PA in patients with PI. Results will be generalisable to the types of patients included in IST-3. Patients presenting <3 hours have larger PI lesions with more mismatch. Large CBV lesions may predict SICH and poor outcome. Results by rt-PA allocation are awaited.
- © 2012 by American Heart Association, Inc.