Blocked Heart Arteries May Presage Stroke
Lead author Dirk M. Hermann is professor of vascular neurology and dementia at the University Hospital Essen in Germany. He says in a press statement their findings reveal "that stroke risk is tightly aligned with coronary atherosclerosis, showing the closely related nature of cardiovascular and cerebrovascular disease".
He calls for more collaboration across different disciplines to better prevent and manage these diseases.
For their study, Hermann and colleagues used a variation of the conventional CT scan to look at heart arteries in 4,180 male and female patients. The patients were aged from 45 to 75, were randomly selected from three German industrial cities, and had no history of stroke or heart attack.
With non-invasive electron beam-computed tomography, the researchers could see how much plaque had built up in the patients' heart artery walls.
They then followed the patients for around 8 years, during which time 92 strokes occurred in the group. 82 of the strokes were ischemic (due to blood clot in brain), and 10 were hemorrhagic (due to bleeding in brain).
Strokes tended to occur in patients around 65 years of age, who had diabetes, higher body mass index, and higher levels of blood pressure and cholesterol.
However, comparing the stroke incidences with the scans taken earlier, the researchers also found the patients whose heart artery blockages were due to coronary artery calcification (CAC) were far more likely to be among the stroke casualties than those without CAC.
A CAC level higher than 400 Hounsfield units (HU, a measure of the density of tissue and other matter seen on a CT scan) was tied to a threefold higher risk for stroke than levels under 399 HU.
The authors note that CAC measures were particularly strong at predicting stroke in the younger participants (under 65) and in those whose risk assessed using conventional risk factors put them at low risk for cardiovascular disease.
Plus, CAC measures accurately predicted stroke in both male and female patients, regardless of whether they had a form of irregular heartbeat called atrial fibrillation, which is often tied to higher risk for stroke.
Hermann says the study shows in assessing patients' risk for stroke, doctors should take into account CAC levels as well as other known factors such as atrial fibrillation.
In a recent study, scientists from the University of Oxford in the UK describe discovering how the brain protects itself from stroke damage. Harnessing this inbuilt biological mechanism could lead to new treatments for stroke, and ways to prevent neurodegenerative diseases in the future, they suggest.
Written by Catharine Paddock PhD