Revascularization-outcome paradox: not only time and collaterals status, but also complete recanalization contribute to good neurological outcome.

The rate of successful recanalization in endovascular trials has not always mirrored the rate of good clinical outcomes, creating a revascularization-outcome paradox. In early experience with the new generation of stent-based thrombectomy devices, 45-77% of patients have achieved good 90-day outcomes despite treatment up to eight-hours after symptom onset. These rates of good functional outcome are clearly higher than those previously reported with other endovascular strategies. We propose that among the factors influencing this difference is the far higher complete recanalization rate and the high ratio of Thrombolysis in Myocardial Infarction 3/Thrombolysis in Myocardial Infarction 2 recanalization obtained with stent retrievers in comparison with previous generation mechanical thrombectomy devices. Recently, we achieved Thrombolysis in Myocardial Infarction 3 in 94% of patients and Thrombolysis in Myocardial Infarction 2 in 6% in a series of patients with acute middle cerebral artery occlusions who were managed with stent-thrombectomy within eight-hours of symptom onset. Good outcomes were achieved in 77%. Extent of recanalization appears to interact with time and collateral supply in determining clinical outcomes.