Ammad Mahmood, MBChB
@AMahmoodNeuro
Major clinical trials generally exclude patients with pre-stroke disability, generally defined as pre-stroke modified Rankin scale (mRS) of ≥2 or 3. Accordingly, thrombectomy guidelines [1, 2] state the benefit of mechanical thrombectomy (MT) for patients with pre-stroke disability is less clear, particularly for those aged >80. Patients with pre-stroke disability are routinely considered for MT particularly when other clinical and radiological factors are favorable, such as early presentation or good ASPECTS score. In this registry-based study, patients with mRS of 2 or 3 who underwent MT in the Catalonia stroke network were examined to assess any association between pre-stroke disability and outcomes, as well as aiming to identify factors predictive of favorable outcome for patients with pre-stroke disability. A favorable outcome in this context was defined as a return to baseline mRS at 90 days.
Between January 2017 and December 2019, 17% (n=409) of patients undergoing MT had pre-stroke mRS 2 (n=313) or 3 (n=96). Patients with pre-stroke disability were older, more likely female, had more co-morbidities and were less likely to be treated with intravenous thrombolysis (IVT). At 90-day follow-up, 24% (n=91) had a favorable outcome and 76% (n=291) had worsened their pre-stroke condition. Pre-stroke disability was not found to significantly lower the chance of achieving a favorable outcome (OR 0.79 (0.57-1.08)). However, those with pre-stroke disability had a higher likelihood of symptomatic intracranial hemorrhage (SICH), as well as higher mortality. This finding was in spite of patients with pre-stroke disability having earlier presentation and more favorable ASPECTS scores. Factors associated with a favorable outcome in the pre-stroke disability population included atrial fibrillation, non-diabetic, lower NIHSS, higher ASPECTS score, earlier admission and earlier recanalization.
These results highlight several points of discussion. Firstly, despite the evidence base being less robust in this population, a significant proportion of patients undergoing MT in real-world practice have pre-stroke disability. The authors highlight the proportion in their sample (17%) is similar to other European centers and lower than American centers where the proportion can be up to one third. Presumably, the proportion of patients being evaluated for IVT and MT with pre-stroke disability in emergency departments is similar, or perhaps higher given they may be less likely to progress on to receive IVT or MT.
The scarcity of clinical trial data in these populations highlights the importance of studies such as this to inform real-world practice. The study highlights that careful selection can identify patients with pre-stroke disability who may benefit from MT. The findings of the pre-stroke disability population having a more favorable radiological profile at baseline and longer admission-to-groin-puncture times suggest that this careful selection is already taking place.
Interestingly, in keeping with other studies, no difference was found in rates of successful recanalization between those with and without pre-stroke disability, suggesting that the procedure is inherently similar in both populations. A difference was observed in rates of SICH, with the risk doubled in those with pre-stroke disability (OR 2.04 (1.11-3.72)). The authors suggest this could be due to the lower than expected rate of SICH in the non-disability population.
In conclusion, this research highlights the utility of considering MT in those with pre-stroke disability. Careful selection of patients with favorable characteristics means this group of patients are as likely to have a favorable outcome and return to their baseline level of function as non-disabled patients. These patients already form a significant proportion of patients evaluated for and undergoing MT, particularly in countries with aging populations, and this real-world data provides assurances about the utility of pursuing revascularization in this group of patients.
References:
1. Turc, G., et al., European Stroke Organisation (ESO) – European Society for Minimally Invasive Neurological Therapy (ESMINT) Guidelines on Mechanical Thrombectomy in Acute Ischemic Stroke. Journal of NeuroInterventional Surgery, 2019: p. neurintsurg-2018-014569.
2. Powers, W.J., et al., Guidelines for the Early Management of Patients With Acute Ischemic Stroke: 2019 Update to the 2018 Guidelines for the Early Management of Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke, 2019. 50(12): p. e344-e418.
