Background: Haemorrhagic transformation (HT) following reperfusion therapies for acute ischaemic stroke often predicts a poor prognosis.
Aims: (1) To identify risk factors for HT, and how these vary with hyperacute treatment [intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT)]; (2) Evaluate the performance of model-based methods to predict HT.
Methods: Systematic review and meta-analysis. Electronic databases PubMed and EMBASE were searched. Studies were assessed for risk of bias using the Quality In Prognosis Studies tool. Pooled odds ratio (OR) with 95% confidence interval (CI) were estimated. For model-based studies, good discrimination was defined as area under curve (AUC) ≥0.7.
Results: A total of 130 studies were included. Atrial fibrillation and NIHSS score were common predictors for any intracerebral haemorrhage (ICH) after reperfusion therapies (both IVT and EVT), while a hyperdense artery sign (OR=2.605, 95% CI 1.212–5.599, I2=0.0%) and number of thrombectomy passes (OR=1.151, 95% CI 1.041–1.272, I2=54.3%) were predictors of any ICH after IVT and EVT respectively. Common predictors for symptomatic ICH (sICH) after reperfusion therapies were age and serum glucose level. Atrial fibrillation (OR=3.867, 95% CI 1.970–7.591, I2=29.1%), NIHSS score (OR=1.082, 95% CI 1.060–1.105, I2=54.5%) and onset-to-treatment time (OR=1.003, 95% CI 1.001–1.005, I2=0.0%) were predictors of sICH after IVT. Alberta Stroke Program Early CT score (ASPECTS) (OR=0.686, 95% CI 0.565–0.833, I2=77.6%) and number of thrombectomy passes (OR=1.374, 95% CI 1.012–1.866, I2=86.4%) were predictors of sICH after EVT. In addition, AUC of model-based methods ranged from 0.543 to 0.957, with 46.6% (48 out of 103) achieving good discrimination.
Conclusion: Several predictors of ICH were identified, which varied by treatment type. Studies based on larger, multi-centre data sets should be prioritised.