Prognostic accuracy and impact of cerebral collateral status on clinical and safety outcomes in acute ischemic stroke patients receiving reperfusion therapy: a systematic meta-analysis

Background: Cerebral collateral status has a potential role in mediating postreperfusion clinical and safety outcomes in acute ischemic stroke (AIS). Purpose: To investigate the prognostic accuracy and impact of collateral status on clinical and safety outcomes in patients with AIS receiving reperfusion therapy. Material and Methods: Studies with AIS patients treated with reperfusion therapy, collateral status assessed using Tan, ASITN/SIR, or similar collateral grading methods and data stratified according to collateral status were included. Relevant data on clinical outcomes, such as functional outcome at 90 days, mortality at 90 days, angiographic reperfusion, symptomatic intracerebral hemorrhage (sICH) and hemorrhagic transformation (HT), were collated and analyzed. Results: A meta-analysis of 18 studies involving 4132 patients with AIS was conducted. Good collateral status was significantly associated with angiographic reperfusion (odds ratio [OR]=1.97, 95% confidence interval [CI]=1.38–2.80; P < 0.0001), sICH (OR=0.67, 95% CI=0.46–0.99; P = 0.042), and 90-day functional outcome (OR=3.05, 95% CI=1.78–5.24; P < 0.0001). However, its association with HT (OR=0.76, 95% CI=0.38–1.51; P = 0.425) and three-month mortality (OR=0.53, 95% CI=0.17–1.69; P = 0.280) did not reach statistical significance. The prognostic accuracy of collaterals for predicting angiographic reperfusion, HT, functional outcome (at 90 days), and mortality (at 90 days) were 63%, 49%, 66%, and 48%, respectively. Conclusion: Cerebral collaterals are significantly associated with clinical and safety outcomes, albeit with a prognostic accuracy range of 48%–66%; thus, evaluation of their patency is a useful prognostic tool in patients with AIS receiving reperfusion therapy.