Background and Purpose-Approximately 23% of Australian hospitals provide Stroke Units (SUs). Evidence suggests that clinical outcomes are better in SUs than with conventional care. Reasons may include greater adherence to processes of care (PoC). The primary hypothesis was that adherence to selected PoC is greater in SUs than in other acute care models. Methods-Prospective, multicenter, single-blinded design. Models of care investigated: SUs, mobile services, and conventional care. Selected PoC were related to care models and participant outcomes. Data were collected at acute hospitalization (median 9 days) and at medians of 8 and 28 weeks after stroke. Results-1701 patients were screened from 8 hospitals, 823 were eligible, and 468 participated. Response rate was 96% at final follow-up. Mean age was 73 years (SD 14). Overall PoC adherence rates for individual care models were SU 75%, mobile service 65%, and conventional care 52% (PϽ0.001). The adjusted odds of participants being alive at discharge if adhering to all or all but 1 PoC was significant (aOR 3.63; 95% CI: 1.04 to 12.66; Pϭ0.043). Important trends at 28 weeks were found for being at home (aOR 3.09; 95% CI: 0.96 to 9.87; Pϭ0.058) and independent (aOR 2.61; 95% CI: 0.96 to 7.10; Pϭ0.061), with complete PoC adherence. Conclusion-Adherence to key PoC was higher in SUs than in other models. For all patients, adherence to PoC was associated with improved mortality at discharge and trends found with independence at home, providing support for the need to increase access to stroke units.

In ischaemic stroke, expansion of the infarct core occurs at the expense of surrounding hypoxic, metabolically compromised tissue over a period of 24 h or more in a considerable proportion of patients. It is uncertain whether hypoxic tissue observed at later times after stroke onset retains the potential for survival or whether such survival has an impact on functional outcome. These factors may determine the effectiveness of therapeutic strategies aimed at salvaging this tissue. We tested the hypotheses that metabolically compromised hypoxic tissue observed within 48 h after onset of ischaemic stroke retains the potential for spontaneous survival and that the impact of such survival on functional outcome is time dependent. Consecutive patients presenting within 48 h of ischaemic stroke were studied with [(18)F]fluoromisonidazole, a ligand binding to hypoxic but viable tissue, and PET. Subjects were grouped into two time epochs, 12 h, based on the interval from stroke onset to the time of tracer injection, and had infarct volumes measured on CT/MRI at 7 days (n = 60). The total ischaemic volume (TIV) and the proportion of the TIV that spontaneously survived (surviving hypoxic volume ratio, SHVR) were defined from the co-registered CT/MRI images. These volumetric measures were correlated with neurological outcome assessed at day 7-10 by percentage change in the National Institutes of Health Stroke Scale (DeltaNIHSS), and at 3 months by Barthel Index (BI) and modified Rankin Score (mRS). Of 66 patients investigated, hypoxic tissue occurred in 33 and outcome data was available in 27. Hypoxic tissue constituted >20% of the TIV in 60% of studies 12 h. The spontaneously surviving proportion of the TIV (median 6.9%) or hypoxic tissue (median 45.9%) was not significantly different in patient subgroups studied 12 h after stroke onset. Spontaneous survival of hypoxic tissue (surviving hypoxic volume ratio) was associated with improved neurological outcome in both time epochs: 12 h, DeltaNIHSS (r = 0.59, P < 0.01) and day 90 mRS (r = -0.46, P < 0.05). The finding that similar proportions of hypoxic tissue survived spontaneously within each time epoch suggests that its fate is not predetermined. The favourable neurological outcome associated with spontaneous survival of hypoxic tissue, even 12-48 h after stroke onset, suggests that the volume of hypoxic tissue that progressed to infarction may represent a valuable target for therapeutic intervention.