Letter by Meyer et al Regarding Article, "Impact of Reperfusion for Nonagenarians Treated by Mechanical Thrombectomy: Insights From the ETIS Registry".

To the Editor: Recently, we read with great interest the article by Drouard-de Rousiers et al, “Impact of Reperfusion for Nonagenarians Treated by Mechanical Thrombectomy: Insights From the ETIS Registry. ” In the past years, guideline-informing randomized stroke trials provided clear clinical evidence for the benefit of mechanical thrombectomy. However, the majority of very elderly patients, including nonagenarians, were excluded from analyses due to exclusion criteria or only small numbers of these patients were enrolled. Accordingly, evidence-based recommendations for patients aged 90+ years were not possible based on these trials, but with an overall positive mechanical thrombectomy effect, there is no clear justification to exclude this patient subgroup from therapy. Given that age is a strong risk factor for stroke and demographics are changing toward a substantial aging world population, clear evidence for the benefit of endovascular therapy strategies is urgently needed. In their study, including 124 patients from the ETIS Registry (Endovascular Treatment in Ischemic Stroke), Drouard-de Rousiers et al investigated the impact of reperfusion on mechanical thrombectomy for nonagenarians. The authors observed that patients with successful reperfusion had the lowest 90-day modified Rankin Scale and further, those with successful reperfusion after the first pass had a reduced 90-day mortality and an increased rate of good outcome (modified Rankin Scale score, ≤3). Therefore, they concluded that in cases of first-pass failure, terminating the intervention might be an advisable procedural strategy for this fragile subpopulation. This interesting finding emphasizes once more the high impact of successful reperfusion on favorable outcomes. Moreover, the observations are in line with previous findings on the firstpass effect as an independent predictor for favorable outcome. Nevertheless, in 37% (14 of 38), good outcome was achieved with >1 pass leading to successful reperfusion (Thrombolysis in Cerebral Infarction [TICI] ≥2b; 10 of 38) or even without successful reperfusion (TICI ≤2a; 4 of 38). Even more interestingly, in 54% (29 of 53) of all first-pass effect cases, 90-day outcome was neither favorable nor good. Therefore, the conclusion of considering a termination of the procedure after failed first-pass reperfusion of TICI ≥2b might not be justified. Furthermore, the safety analysis showed low overall rates of symptomatic cerebral hemorrhages of 4% and no significant differences comparing complications in groups of successful and unsuccessful reperfusion justifying further thrombectomy attempts. These findings are consistent with a previous analysis on retrieval attempts showing that the first recanalization attempt has the highest per pass rate of successful reperfusion rate and ≤3 retrieval attempts still lead to increased successful reperfusion rates and favorable outcomes. In conclusion, the study by Drouard-de Rousiers et al provides important clinical evidence of procedural and functional outcome dynamics underlining that nonagenarians should not be excluded systematically from mechanical thrombectomy. Similar to the latest results on nonagenarians, they found low rates of sICH and high rates of 90-day mortality but could show that mortality decreases and good outcome increases if the first thrombectomy maneuver leads to a successful reperfusion. Even more interestingly, a relatively high number of patients did not reach a good functional outcome at 90 days despite successful reperfusion after the first pass. Therefore, future studies should focus on why very elderly patients with predictors for good outcome still experience a 90-day poor outcome and how to improve the postinterventional phase and neurorehabilitation minimizing complications leading to increased mortality in this fragile subgroup.