In the present study, we explored (1) the influence of risk factors on related outcomes in AIS patients treated with MT caused by anterior circulation LVOs; and (2) the efficacy and safety of MT alone and bridging therapy. First, with the use of multivariate logistic regression, we observed that two factors (baseline NIHSS score and groin puncture to reperfusion interval time) determined outcomes in patients treated with MT; lower admission glucose levels determined a good outcome, showing in the decision ranking that these factors were primary factors for outcomes in patients treated with MT. Second, bridging therapy had no significant benefit over MT alone in terms of procedural outcomes, recanalization rate, and clinical and safety outcomes. Finally, our constructed nomograms could accurately predict outcomes in AIS patients treated with MT.
A previous meta-analysis study showed that patients with low NIHSS scores (< 6) experienced better functional outcomes following treatment with MT (14). Our study also demonstrated that patients treated with MT experienced superior clinical outcomes in low and high NIHSS scores. Madsen and colleagues revealed that males suffered a poor 90-day outcome after MT for AIS (15), which was similar to our findings. Previous studies reported that advanced age was associated with a worse outcome (16, 17). Our results showed that age was not an independent factor for clinical outcomes, which was similar to the results published by Andrews (18). Elkind and colleagues have reported that systemic inflammation is correlated with poorer outcomes in patients with stroke (19). The WBC (neutrophil and lymphocyte counts) was associated with long-term outcome and hemorrhagic complications in patients treated with MT (20). Broocks also reported that elevated admission blood glucose was associated with increased brain edema in patients with endovascular therapy (21). Our findings showed that high WBC and admission glucose levels were unfavourable outcomes in AIS patients treated with MT, suggesting that these laboratory values could help to identity patients at higher risk of impending unfavourable outcomes. Additionally, in our study, the groin puncture to reperfusion interval time was a predictor of a favourable outcome. Therefore, we should shorten the groin puncture to reperfusion interval time to improve functional outcomes in patients treated with MT.
The nomogram is a visual and widely approval approach to predict tumour prognosis according to clinical features (22). In recent years, emerging reports have shown a better predictive ability of nomogram for predicting clinical outcomes in patients with AIS (9, 10). However, nomograms are rarely applied for functional outcomes in AIS after MT. The present study aimed to establish a nomogram to predict 3-month outcomes in patients treated with MT. According to our nomograms, admission glucose, baseline NIHSS score and groin puncture to reperfusion interval time were included in the final model for a good outcome through a stepwise algorithm, and the findings for death were similar to those of the good outcome multivariate analyses. Therefore, our constructed models further demonstrated that these factors should be considered when predicting the outcomes of AIS after MT.
A recent meta-analysis conducted by the HERMES collaborators suggested a significant benefit of bridging therapy over intravenous thrombolysis, with a positive odds ratio of 1.72 (23). However, the findings regarding the efficacy and safety of bridging therapy and MT alone remain uncertain. Mistry and colleagues published a meta-analysis that bridge therapy had a better functional outcome and a higher rate of successful recanalization compared with MT alone (24). However, the MR CLEAN, ESCAPE and REVASCAT trials suggested no significant difference in the effect between bridging therapy and MT alone (4, 25, 26). Subgroup analyses showed that patients with MT alone had higher mortality at 3 months compared with patients who received bridging therapy in the ESCAPE trial. The mortality of MT alone was slightly increased but without statistical heterogeneity in the REVASCAT trial. In the subgroup analyses of these trials, each group had a small size: 30 (13%) patients with MT alone in MR CLEAN, 45 (27%) in ESCAPE, and 33 (32%) in REVASCAT. In this study, although the group that received MT alone had higher blood urea nitrogen (BUN) levels, a higher proportion of wake-up stroke and longer OTD time compared with patients who received bridging therapy, no significant difference was found in the procedural outcomes, recanalization rate, and clinical and safety outcomes between MT alone and bridging therapy. More importantly, the sample size of each group was more than 100 in the present study. Therefore, our study suggested that bridging therapy had no significant benefit over MT alone in terms of clinical and safety outcomes.
A major advantage of the current study is that this study explored the prognostic significance of both MT alone and bridging therapy for LVO in AIS patients of the anterior circulation. The limitations of this study should be acknowledged when interpreting these results. First, this was a retrospective and single-centre study, and the sample size of this study was small. There might be a selection bias in the retrospective study regarding different time of symptom onset of MT alone and bridging therapy. Validation with a prospective and multi-centre randomized study with a large sample is required. Additionally, our nomograms were further confirmed in an external cohort.