Ischaemic stroke patients with dementia are less likely to receive a thrombectomy, a large US study has found.
Mechanical thrombectomy is an advanced treatment that uses a device to remove the obstructing blood clot from arteries within the brain.
Researchers found that it could have “significant absolute benefit” for stroke patients with a large vessel blockage, especially when used within six hours of symptom onset.
In the new study, acute ischaemic strokes tended to be more disabling in the group with dementia. However, just over three per cent of those patients were treated with mechanical thrombectomy, compared with six per cent of those without dementia.
Thrombectomy has a six-hour recommended time window, though treatment sometimes can be given up to 24 hours after the start of symptoms.
The research, published in the American Heart Association journal Stroke: Vascular and Interventional Neurology, found no difference between the two groups in the use of intravenous clot-busting drugs, which can be given up four hours and a half after symptoms begin.
“The main takeaway point from this is that patients with dementia present with a higher stroke severity at onset. However, the number of thrombectomies were lower for that patient population,” said the study’s lead author, Dr Hamidreza Saber, neuro-interventional fellow at the University of California, Los Angeles, David Geffen School of Medicine.
About one in ten people having a clot-caused stroke also have dementia, according to the American Heart Association, but treatment teams fear mechanical thrombectomy could cause a brain haemorrhage in stroke patients with dementia.
According to the study, people with dementia who were treated with mechanical thrombectomy were more likely to develop intracranial haemorrhage, or bleeding within the skull. But researchers noted that other blood vessel changes caused by dementia could account for that increased risk.
The report, one of the first US studies to examine hospital admissions for acute ischaemic stroke in people with and without dementia, looked at nearly 180,000 hospital admissions for acute ischaemic stroke from October 2016 through December 2017.
Limitations included the fact that the admissions data did not identify which patients were eligible for mechanical thrombectomy and how much time had passed between the onset of stroke symptoms and hospital care.
Dementia in people who received mechanical thrombectomy did not appear to increase the odds of dying in the hospital, nor did it decrease the chances of a favourable outcome at hospital discharge, the findings suggested.
The study highlighted that dementia patients are getting excluded from thrombectomy treatment at a higher rate, although their outcomes from that treatment are not necessarily poorer, Dr Saber said.
Dr Gillian Gordon Perue, assistant professor of clinical neurology at the University of Miami in Florida, added: “This is a very exciting paper and an eye-opener.
“The research is a first snapshot of a moment in time of ischaemic stroke treatment in US hospitals for people with and without dementia. It is an area where we need more data.”
As the US population ages, the number of people with cognitive disorders is expected to grow.
The study’s lead author said the next steps towards improving care for these people include using better tools to assess dementia and producing more data specific to people with the condition, such as markers that could predict how those undergoing blood flow-restoring therapies will fare.
“We want to deliver precision medicine,” Saber added. “Not all dementia patients are the same, so who are the dementia patients who would most benefit from a treatment, and who would not?”
