Early morning blood pressure readings may help identify intracranial arterial stenosis.
Asymptomatic intracranial stenosis (ICAS), a narrowing of an artery inside the brain, is caused in many cases by atherosclerosis — a buildup of plaque inside the artery wall that reduces blood flow to the brain. Atherosclerosis in turn is caused by high blood pressure, diabetes, smoking, and elevated “bad” cholesterol. Other risk factors include obesity, heart disease, family history, and advanced age. Asymptomatic intracranial stenosis is possibly the most frequent cause of stroke in the world.
Researchers at Mayfield Clinic of Cincinnati, Ohio, write that if atherosclerosis is severe enough to cause symptoms, it carries a high risk of causing stroke and can lead to brain damage and death. Treatments aim to remove plaque buildup and prevent blood clots. They also say that ICAS is responsible for 8 to 10 percent of strokes in the U.S. and affects certain ethnic groups more than others including African Americans, Asian Americans, and Hispanics. Patients with intracranial artery disease tend to be younger than those with carotid artery disease.
New research published in the American Heart Association’s Hypertension journal, says that measuring ambulatory blood pressure (ABP) in the early hours of the morning is predictive of ICAS. The study authors examined the strength of association between ICAS and systolic blood pressure (SBP) across different time-windows using 24-hour ambulatory blood pressure monitoring in 757 consecutively recruited patients with hypertension. ICAS was diagnosed in 16.8 percent of patients, of whom 50.4 percent had stenosis and 64.6 percent had ICAS in 2 or more vessels. They found that patients with ICAS, especially of multiple vessels “had significantly higher early morning SBP. The differences remained significant after adjustment for cardiovascular risk factors and SBPs at other time-windows of the day.” The most critical time to take blood pressure was between 05:00 and 07:59 a.m.
They concluded that there is “a significant association between early morning SBP and asymptomatic ICAS in patients with hypertension after accounting for conventional cardiovascular risk factors.” Moreover, their findings “highlight the importance of morning SBP as a cardiovascular risk factor and should be validated in prospective studies.” The results are important, as early morning SBP could be a promising target to prevent ICAS and in turn, to prevent stroke. Early detection may allow for therapeutic intervention.