WCN 2015 - Experts discuss strong link between stroke and dementia

Press Release

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WCN 2015: “Changing Neurology Worldwide” – Santiago, Chile, 31 October– 5 November 2015

Stroke second leading cause of death – experts discuss strong link between stroke and dementia

Stroke remains a major cause of death. The overall incidence of stroke in younger adults is on the rise globally and a new study reveals that this age group now represents almost half of the total burden. There are also strong links between stroke and dementia. With the risk factors being largely identical,this opens the way to common preventive strategies, experts stress at the World Congress of Neurology currently being held in Santiago de Chile. A lot of new stroke-related research is being presented, including findings on the important role of neuroimaging for therapeutic decisions.

Santiago de Chile, 31 October 2015–“Stroke has finally been recognized at international level – for example at the UN Post-2015 Sustainable Development summit – as one of the core diseases globally in need of prevention, improved management and continued surveillance,” Bo Norrving, Professor of Neurology at Lund University, Sweden, said at the World Congress of Neurology (WCN 2015). About 3,500 participants are gathered in the Chilean capital Santiago for the world's largest neurology event. “This reflects the high burden the disease imposes on individuals, their families and societies.Stroke is the second leading cause of death, and the most common cause of disability in adults. Modern neurology is making major advances in the prevention, therapy and rehabilitation of stroke. Nonetheless, the disorder still poses major challenges,” he added.

The latest data on the incidence, prevalence, mortality and socioeconomic consequences of stroke at global, regional and national levelshave been published just in time for World Stroke Day on 29 October in a special issue of the journal Neuroepidemiology(www.karger.com/ned), “The Global Burden of Stroke”, which is co-edited by Prof Norrving.These papers are offered open access to readers worldwide. One of the major findings of the comprehensive research programme which assesses mortality and disability from major diseases, injuries and risk factorsis thatthere is still no country in the world, where the burden of stroke, in terms of the absolute number of individuals affected by or dying from stroke, has declined over the last two decades. The bulk of stroke burden continues to be borne by developing countries. The overall incidence of stroke in younger adults is increasing globally and now represents almost half of the total burden.

“At this year’s WCN the spotlight is firmly onthe strong link between the two largest neurological diseases: stroke and dementia. One in three people will develop either of these,” noted Prof Norrving. “The pathologies of both conditions seem to interact, and it is important to point out that they have virtually the same risk factors, which include high blood pressure, cigarette smoking, obesity or lack of physical activity. These findings represent an opportunity to prevent or delay both conditions.”

The potential for modifying risk factors isset to be underlined in a WCN lecture by the internationally renowned stroke expert Prof Vladimir Hachinski from Western University, London, Canada. “In the past 20 years, stroke incidence has increased by 225 percent in low and middle income countries while it has declined by 42 percent in high income countries”, he said. “Trends in the latter also reflect decreasing incidence of dementia. The data suggests that the big differences are not due to changes in the genetic makeup, but improvements in risk factor control,” he concluded.

mHealth permits remote neuroimaging interpretation

Research on progress in the field of eHealth and mHealth is another of the new insights in the field of stroke prevention, diagnosis and treatment presented at WCN 2015. “For example, we are seeing data from the first study that was able to demonstrate that in acute stroke, neuroimaging data can be interpreted well remotely,” Prof Norrving reported. Researchers from New York compared the diagnostic accuracy of different mobile devices in acute computertomography (CT) interpretation of various ischemic stroke findings among various readers. iPhone and iPad proved to have similarly good diagnostic accuracy for acute ischemic stroke, supporting their use for remote neuroimaging interpretation. “Confirmatory studies in clinical practice will now be necessary,” Prof Norrving commented.

Cryptogenic stroke: From heart to brain

New findings are also shared on the pathogenesis of cryptogenic stroke are also a feature of WCN. “A study from Munich, Germany, using a very interesting approach further supports the hypothesis that the blood clot in many cryptogenic acute ischemic strokes may origin in the heart,” noted Prof Norrving. The researchers had collected thrombi of 145 patients with large vessel occlusion undergoing mechanical thrombectomy. Analysis of the thrombus material showed similar thrombus structures and similar clinical and interventional characteristics for cardio-embolic and cryptogenic subtypes of stroke, suggesting that cardio-embolic mechanisms may account for a majority of cryptogenic strokes. Stroke of undetermined cause is a major health issue. 30 to 40 percent of first time strokes are estimated to be cryptogenic. Establishing the cause of stroke is vital to determine functional prognosis, decrease the risk of future strokes, and select appropriate preventative care.

Neuroimaging provides new opportunities for stroke management

Prof Norrving also addressed another topical item in stroke research: “Among the most important developments in acute stroke therapy is the increasing scientific evidence regarding the mechanical removal of thrombi from the brain vessels. A growing number of recent studies have demonstrated the high efficacy and safety of mechanic thrombectomy in acute ischemic stroke. Now, an important challenge concerns the question which neuroimaging modality should preferably be used in this intervention. New research, some of which will be presented at the WCN, demonstrates that imaging with computer tomography angiography and perfusion should be the main initial imaging modality in clinical practice.”

Computer tomography perfusion (CTP)has already superseded magnetic tomography thanks to a number of advantages. These include automatic registration of viable and non-viable brain tissue, the ability to generate concurrent angiographic data,and wide availability. Among the other positives are the short timeframe in which it can be used and the fact that it is not limited by contra indications.

Acute intracerebral haemorrhage: aggressive blood pressure lowering proves beneficial

Some sessions and presentations at WCN 2015 in Santiago are devoted to the management of acute intracerebral haemorrhage.Intracerebral haemorrhage occurs when a diseased blood vessel insidethe brain bursts, allowing blood to leak into brain tissue, causing damage to the brain, which may present symptoms similar to that of a stroke. “Further evidence has accumulated showing that immediate blood pressure lowering towards systolic levels below 140 mmHg is beneficial and should therefore be used in clinical routine,” Prof Norrving said.

Results from the INTERACT 2 study, together with other trial and observational data, has pushed guideline recommendations and clinical practice around the world towards more aggressive management of blood pressure in intracerebral haemorrhage patients – towards a systolic target of less than 140 mmHg rather than the conventional level below 180 mmHg. Further trial data also highlights the importance of early control of systolic blood pressure, not just in the first 24 hours after the event, but also over the course of the days that follow.

Widely used drug shows no effect in new trial

“With the high prevalence of stroke on a global scale and the significance of effective and immediate treatment in the case of an acute event, it is all the more important that we are relying on therapeutic strategies supported by scientific evidence,” Prof Norrving explained. “One drug, cerebrolysin, a biotechnologically produced peptide, is commonly used in stroke treatment in many parts of the world, but the evidence base so far is weak. A new trial conducted in Austria, Germany, Romania and Russia and presented at WCN shows no effect.”

Cerebrolysin was successful in experimental models of cerebral ischemia and showed beneficial effects in clinical trials in acute stroke. One large prospective, randomized, double blind multicenter study (CARS 1) also demonstrated a significant persistent effect. However, the new CARS 2 study did not confirm these findings and showed no significant superiority as compared to placebo. Further large scale studies on the effect of cerebrolysin in stroke are on going.

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Sources: WCN Abstract 2015 Anderson, management of acute intracerebral haemorrhage; WCN 2015 Abstract, Boeckh-Behrens et al., Thrombushistology and cryptogenic stroke – A different approach to detrmineetiology; WCN Abstract Donnan, Stroke MT 3.2 – New opportunities for managemtn of acute stroke; WCN 2015 Abstract Guekht et al., Cerebrolysin and recovery after stroke (CARS 2): A randomzed, placebo-controlled, double-blind multicentre clinical study; WCN 2015 Abstract Hachinski, The global challenge of dementia: Targeting the vascular contribution; WCN 2015 Abstract Levine, Mobile devices for remote acute stroke neuroimaging interpretation: diagnostic accuracy.