Increasing age was associated with worse outcomes, but only in the presence of partial recanalization after the procedure.
The quality of recanalization following mechanical thrombectomy seems to influence the relationship between age and outcomes in patients with strokes caused by large-vessel occlusions (LVOs), according to the results of a retrospective, single-center study published online June 1, 2018, in the Journal of NeuroInterventional Surgery.
Increasing age was associated with worse overall outcomes, but only among patients in whom thrombectomy resulted in partial reperfusion (mTICI 2b), researchers led by Mahesh Jayaraman, MD (Brown University, Providence, RI), report. Age was not significantly associated with outcomes in the presence of recanalization that was incomplete (mTICI 0 to 2a) or near complete (mTICI 2c/3).
“With complete recanalization, there is a similar likelihood of independence at 90 days irrespective of age,” the authors write. “Further investigation of this relationship between degree of recanalization (separating mTICI 2b and 2c/3) is warranted. As endovascular technology and techniques improve and the likelihood of achieving complete recanalization increases, the overall outcomes in older patients may approach those of younger patients.”
Several recent trials have shown that mechanical thrombectomy plus best medical therapy improves outcomes in patients with ischemic strokes caused by LVOs in the anterior circulation. Though thrombectomy has benefits across age groups, older patients have worse overall outcomes. Achievement of complete or near-complete reperfusion, on the other hand, is associated with better outcomes.
Procedural Success Not a Function of Age
To explore the interplay between age, outcomes, and completeness of reperfusion, Jayaraman and colleagues examined data from 157 patients who underwent mechanical thrombectomy for an emergent LVO in the internal carotid artery or the M1 or proximal M2 segment of the middle cerebral artery at their center. All patients underwent noncontrast CT and CT angiography before thrombectomy, which involved a combination of a stent retriever and a local aspiration catheter as the primary technique.
The procedure resulted in incomplete (mTICI 0 to 2a), partial (mTICI 2b), and near-complete (mTICI 2c/3) reperfusion in 24, 61, and 72 patients, respectively.
In the partial recanalization group, there was a link between older age and poorer outcomes, determined by mRS score, such that every 1-year increase in age was associated with an increase in mRS score of 0.06 points (P = 0.0007). With increasing age, outcomes in this group moved closer to those seen in patients with incomplete reperfusion after thrombectomy.
Similar relationships between age and outcomes were not seen in the incomplete and near-complete recanalization groups.
The researchers also examined whether the likelihood of achieving complete recanalization is related to age, and found that older patients were just as likely as their younger counterparts to achieve it.
“That is to say, the likelihood of procedural success was not a function of age. Indeed, there appears to be a greater benefit of complete recanalization in older patients than younger ones,” the authors write.
They say the study is relevant in the modern thrombectomy era because it “underscores the importance of separately reporting mTICI 2b versus mTICI 2c/3 recanalization in all future series of thrombectomy. As others have suggested, we believe that mTICI 2c should be the goal of thrombectomy.”
Moreover, “further maturation of thrombectomy techniques may allow greater rates of mTICI 2c/3 reperfusion, and evaluation of the relative efficacy of novel techniques should account for the age of the patient,” they continue. “As our results highlight, achieving mTICI 2b reperfusion in an 80-year-old patient is not the same as in a 50-year-old.”
The researchers note that workflow times in this study were speedier than in the published trials. The median and fastest quartile for times from symptom onset to recanalization, for example, were 225 and 154 minutes in the mTICI 2c/3 group and 243 and 181 minutes in the mTICI 2b group in this study, and 285 and 210 minutes in pooled trial results.
“While we feel this may allow us to demonstrate the importance of achieving near-complete recanalization, it may also be the case that the difference in recanalization time contributes to some extent to the improved outcomes,” Jayaraman and colleagues write.
Sources:
Jayaraman MV, Kishkovich T, Baird GL, et al. Association between age and outcomes following thrombectomy for anterior circulation emergent large vessel occlusion is determined by degree of recanalization. J NeuroIntervent Surg. 2018;Epub ahead of print.
Disclosures:
Jayaraman reports no relevant conflicts of interest.
