Background and Aims
Mechanical thrombectomy has become standard of care for management of large vessel occlusions with small ischaemic core. Recent randomised controlled trials have attempted to broaden the application of thrombectomy to large core ischaemic strokes (LCIS). However, it is unclear if there is a difference in the magnitude of effect towards functional independence between these two groups. This has implications for informed consent as the probability of favourable outcomes may differ.
We aim to determine the relative difference in obtaining functional independence defined as a modified Rankin Scale (mRS) of 0 – 2 in LCIS thrombectomy compared to traditional thrombectomy.
Methods
We conducted a meta-analysis by searching PubMed and EMBASE databases to identify all randomised controlled trials published up to March 2023 for large core thrombectomy, as defined by an Alberta Stroke Programme Early CT Score (ASPECTS) of ≤ 5. Functional independence was defined as a mRS of ≤ 2. Random effects meta-analytic models were utilised to summarise the effect of intervention compared to control. The number needed to treat and absolute risk difference was calculated.
Results
Four studies met the eligibility criteria. In a random effects model, statistical significance was demonstrated in LCIS thrombectomy towards regaining functional independence (OR 3.07, 95% CI 2.13 – 4.42). The number needed to treat (NNT) was 7, absolute risk reduction (ARR) was 13.9%, and mRS ≤ 2 was achieved in 24.2% of patients with LCIS thrombectomy.
However, this is lower when compared to the conventional thrombectomy, with a recent meta-analysis demonstrating a NNT of 5, an ARR of 26.6%, and a mRS ≤ 2 achieved in 45.9% of patients.
Conclusion
LCIS thrombectomy increases the rate of functional independence but not to the same extent as conventional thrombectomy. This should be clearly stated to patients and families during the informed consent process when considering intervention in large core ischaemic strokes.