Elena Zapata-Arriaza, MD, PhD
@ElenaZaps
Large vessel occlusion (LVO) with minor neurological deficit can occur in about 24% of patients with acute ischemic stroke (AIS). The lack of clinical trials addressing this type of patient generates different therapeutic approaches, which impact the natural history of the disease. Lee et al. aim to determine the likelihood of early neurologic deterioration (END) in patients with LVO and low NIHSS treated with rtPA.
The authors performed a retrospective analysis of AIS with low NIHSS (≤7) and LVO (M1, M2, terminal carotid artery -ICAT- and tandem lesions) treated with rtPA from 2014-2019 in a telestroke platform. Most of the included patients were transferred to a tertiary hospital with endovascular treatment availability, and they received CTA on arrival. END was defined as NIHSS worsening of ≥4 within 24 hrs of stroke onset that was not related to symptomatic hemorrhage.
Among the 81 patients with LVO+low NIHSS included in the analysis, 34.6% underwent END (median NIHSS worsening of 10.4 points). Mentioned END was significantly related to older age, diabetes and more proximal occlusion (M1/ICAT). On hospital discharge, patients with END were less likely to be discharged at home (25% vs 66%, p=0.004). Good functional outcome at three months occurred less often in patients with END (18% vs 81%, p=0.007). Finally, there was a significant difference in CBV<30% volume (CTP RAPID software) in the END group compared with those without decline.
The management of patients with large vessel occlusion and mild deficit presents multiple therapeutic options in the absence of robust scientific evidence based on clinical trials, despite being up to 30% of patients with LVO. According to what was published in this article, a third of these patients will have a neurological deterioration of up to 10 points, despite being treated with rtPA. In addition, this group of patients with neurological deterioration will have a worse functional result and are less likely to be discharged home. All this taken together should make us think that low NIHSS with LVO constitutes a high-risk group of worsening despite medical treatment, the greater the more proximal the occlusion. Therefore, the debate is served on whether it is more beneficial to propose mechanical thrombectomy (MT) from the beginning or to delay it after the worsening. However, given the low recanalization rate of rtPA in proximal occlusions and the risk of clinical worsening, it is possible that considering mechanical thrombectomy from the outset is not unreasonable, in light of its demonstrated safety and efficacy.
We have two possible scenarios:
Scenario 1: LVO + low NIHSS treated with rtPA and clinical worsening due to collateral claudication: As long as the perfusion parameters allow it, mechanical thrombectomy should be considered, but we would have lost valuable time to resolve oligohemia, and the thrombus may have reorganized, making it difficult to extract.
Scenario 2: LVO + NIHSS low treated with rtPA without clinical worsening. In this case, recanalization of the occlusion may occur (However, this treatment has shown low efficacy in patients with LVO-AIS due to the low rates of recanalization), or collaterals may maintain stable cerebral perfusion despite occlusion. In this case, the long-term implications of chronic intracranial occlusion associate a higher risk of vascular cognitive deterioration and a poorer functional prognosis.
All this taken together could lead us to employ MT for LVOs independently of the NIHSS. However, we must take into account the experience of the interventional neuroradiology team, the laterality and cortical symptoms of stroke, and data on cerebral perfusion imaging among others to make a consensual decision. In any case, it seems important to consider endovascular treatment as early as possible to minimize possible ischemic damage, claudication of collaterals, and organization of the thrombus.
