From the Guidelines
The worst type of occlusive strokes to have are tandem strokes, which involve an acute ischemic event in a carotid territory with an extra-cranial ICA stenosis or occlusion and a co-incident ipsilateral large vessel occlusion, including MCA occlusion, due to their poor response to thrombolytic therapy and high rates of permanent disability and death. The Middle Cerebral Artery (MCA) stroke is a significant component of tandem strokes, which account for 20-30% of all ischemic stroke cases, and approximately 50% of all extracranial ICA occlusions presenting as acute stroke will have a MCA occlusion as well 1. Tandem strokes have a larger clot burden, which impedes the delivery of tissue plasminogen activator to the intra-cranial vasculature, reducing its efficacy and resulting in poor recanalization rates with thrombolysis 1.
Some key characteristics of tandem strokes include:
- Poor response to thrombolytic therapy, with recanalization rates not exceeding 10% 1
- High rates of permanent disability, ranging from 40 to 69% 1
- High mortality rates, seen in 16-55% of cases 1
- Low rates of good recovery, with functional independence seen in only 2-12% of cases 1
In contrast, isolated carotid-related strokes, which do not involve a co-incident ipsilateral large vessel occlusion, may have a slightly better prognosis, but still pose a significant risk of disability and death 1. The presence of an ipsilateral MCA occlusion in carotid athero-thrombosis is usually related to an artery-to-artery embolism, with platelet-rich lytic-resistant clot generated at the carotid plaque 1.
Overall, the severity of any stroke ultimately depends on the location, extent of collateral circulation, time to treatment, and whether reperfusion therapy can be administered quickly 1. Immediate medical attention is crucial for any suspected stroke, as timely treatment can significantly improve outcomes.
From the Research
Types of Occlusive Strokes
- Occlusive strokes can occur in various blood vessels, including the middle cerebral artery (MCA), internal carotid artery, and basilar artery.
- The severity and outcome of an occlusive stroke depend on the location and severity of the occlusion, as well as the promptness and effectiveness of treatment.
Middle Cerebral Artery (MCA) Occlusion
- MCA occlusion is a serious type of occlusive stroke, with studies suggesting that it can have poor outcomes if not treated promptly and effectively 2, 3.
- The MCA is divided into segments, including M1 and M2, with occlusions in these segments having different treatment approaches and outcomes.
- M2 segment occlusions have been found to have high recanalization rates and favorable outcomes with endovascular treatment, although the evidence is limited compared to M1 occlusions 3, 4.
Comparison of MCA Occlusion to Other Types of Occlusive Strokes
- While MCA occlusion is a serious condition, other types of occlusive strokes, such as those occurring in the internal carotid artery or basilar artery, can also have poor outcomes if not treated promptly and effectively.
- The optimal treatment approach for each type of occlusive stroke depends on various factors, including the location and severity of the occlusion, as well as the patient's overall health and medical history.
- Studies have compared the efficacy of different treatments, including tenecteplase and alteplase, for occlusive strokes, with some suggesting that tenecteplase may have superior clinical efficacy for patients with large-vessel occlusion 5, 6.
Predictors of Outcomes for MCA Occlusion
- Several factors have been identified as predictors of outcomes for MCA occlusion, including the severity of symptoms, as measured by the National Institutes of Health Stroke Scale (NIHSS) score, and the promptness and effectiveness of treatment 2, 4.
- Advanced age and time to treatment beyond 6 hours from symptom onset have not been found to be predictive of poor outcome with thrombectomy for MCA M2 segment occlusion 4.