Early morning SBP signals silent brain stenosis

Oct 28 2013

By Sara Freeman, medwireNews Reporter

Ambulatory systolic blood pressure (SBP) in the early hours of the morning is predictive of asymptomatic intracranial arterial stenosis (ICAS), the results of a cross-sectional study in China suggest.

Data on 757 consecutively recruited patients show that the most critical time is between 05:00 and 07:59 hours.

Indeed, while the mean SBP was highest in patients with ICAS than in those without at all time periods of the day studied, the difference only remained significant in multivariate analysis when this early morning period was considered (131 vs 128 mmHg).

“[A] significant and independent association was found between early morning SBP and the presence of ICAS after accounting for established cardiovascular risk factors and SBPs at other time-windows of the day,” Ding-Liang Zhu (Ruijin Hospital, Shanghai) and team write in Hypertension.

The findings are important, as early morning SBP could be a promising target to prevent ICAS, which in turn could play a role in stroke prevention, the authors say. ICAS is more prevalent among people of Asian ethnicity than White individuals, however, and further validation of their findings is warranted, they add.

The average age of the study population was 60 years and just over half (58.7%) were male, 15.9% had diabetes, and almost 70% were being treated with antihypertensive medication. The median duration of hypertension was 11 years.

During the study patients underwent computerized tomographic angiography of the whole brain at recruitment and 24-hour ambulatory blood pressure monitoring.

Asymptomatic ICAS was diagnosed in 16.8% of patients, with at least 50% stenosis in 50.4% of patients and at least two intracranial arteries with stenosis in 64.4%.

A linear relationship was found between early morning SBP and the presence of ICAS with 26% higher odds for ICAS and a 46% higher chance of it affecting multiple cerebral arteries with every 10 mmHg rise.

“Our study extends previous observations by illustrating a significant association between early morning SBP and sub-clinical cerebral arterial damage,” the team observes.

The researchers conclude: “Future analyses are warranted to determine whether these findings translate into prognostic significance toward incident stroke.”

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