Thrombolysis and thrombectomy (in the anterior and posterior circulation)

For nearly two decades, intravenous tissue plasminogen activator (tPA or alteplase) administered within 4.5 h was the only treatment for acute ischemic stroke. This talk will review current standards of treatment for anterior and posterior circulation acute ischemic stroke. Recent clinical trials have shown that alteplase given in extended time window or to wake-up stroke patients with favourable CT or MRI-perfusion profile, leads to improved functional outcomes. Although patients with posterior circulation stroke were excluded from these trials, several observational studies demonstrated comparable efficacy and safety profiles of alteplase within 4.5 h and in extended time window, with few studies suggesting a lower risk of hemorrhagic complications in these patients. However, alteplase only results in effective reperfusion in 20–30% of patients with anterior circulation large vessel occlusion (LVO) strokes and ~ 4% of patients with basilar artery occlusion (BAO). Tenecteplase, a genetically modified variant of alteplase with greater fibrin specificity and longer half-life than alteplase, is the most promising alternative thrombolytic agent. A more effective treatment for LVO is retrieving the clot mechanically with a procedure called mechanical thrombectomy. Several clinical trials demonstrated that mechanical thrombectomy for anterior circulation LVO stroke doubled the odds of disability-free survival compared to alteplase alone. Although recent trials comparing mechanical thrombectomy to standard medical therapy in BAO were underpowered and influenced by equipoise issues, the benefit of mechanical thrombectomy was demonstrated in patients with moderate-severe clinical syndromes (NIHSS ≥ 10). This suggested that thrombolysis might be the optimal treatment in those with milder deficits.