About 10% of apparently healthy middle-aged persons have had at least one silent cerebral infarction, a lesion with MRI characteristics of previous infarcts but no clinical symptoms of stroke, according to Rohit R. Das, MD, and colleagues. Silent cerebral infarctions are associated with an increased risk for subsequent stroke and cognitive impairment, the researchers reported in the June 26 online Stroke.
“The findings reinforce the need for early detection and treatment of cardiovascular risk factors in midlife,” said Sudha Seshadri, MD, coauthor of the study and Associate Professor of Neurology at Boston University School of Medicine.
The researchers evaluated MRI findings from approximately 2,000 people (average age, 62) who are part of the Framingham Offspring Study (children of participants in the original Framingham Heart Study). Evidence of at least one silent cerebral infarction was observed in 10.7% of patients with no prior symptoms of stroke. “We saw this in persons in their 50s and 60s, but some of these persons may have developed it even earlier. So clearly, clinical stroke is just the ‘tip of the iceberg’ of brain injury due to exposure to vascular risk factors,” Dr. Seshadri told Neurology Reviews.
The study also documented, for the first time, a significant correlation between silent cerebral infarction and atrial fibrillation, the most common form of heart arrhythmia, or irregular heartbeat, in people older than 65. “In our data, atrial fibrillation increased the risk of prevalent silent cerebral infarction more than twofold,” said Dr. Seshadri. Hypertension and systolic blood pressure were also associated with an increased prevalence of silent cerebral infarction.
“We should be screening all our neurology patients for stroke risk factors, such as hypertension,” noted Dr. Seshadri. She added that recognizing and addressing these risk factors will prevent this covert damage and may lower the risk of subsequent stroke and cognitive decline. However, neither she nor coauthor Philip A. Wolf, MD, recommended brain imaging to screen for silent cerebral infarction, due to the expense and uncertain efficacy. A silent cerebral infarction incidentally found should trigger screening for other stroke risk factors.
“One should also carefully examine the patient for subtle cognitive and physical deficits, discuss the warning signs of stroke, and monitor . . . more carefully for stroke and cognitive decline,” noted Dr. Seshadri.
“Since we have this population under rather intensive surveillance for stroke, it is clear these silent cerebral infarctions are clinically silent and occur in otherwise healthy persons whose risk factor levels are not ‘too bad,’” Dr. Wolf, Professor of Neurology, Medicine, and Public Health at Boston University School of Medicine and the principal investigator for the Framingham Heart Study, told Neurology Reviews.
“This emphasizes the need to vigorously control blood pressure, particularly in persons with elevations of other risk factor levels. Persons with multiple borderline abnormal risk factors warrant particular attention,” he concluded.
—Janis Kelly