The relationship between the morning blood pressure surge and low-grade inflammation on silent cerebral infarct and clinical stroke events

Objective: Morning blood pressure surge (MBPS) has been shown to be a risk factor for cardiovascular disease and is associated with vascular remodeling. This study investigated whether the cerebrovascular risk of MBPS is modified by low-grade inflammation. Methods: We evaluated ambulatory BP, high sensitivity C-reactive protein (hsCRP), and brain MRI at baseline in 514 Japanese hypertensive patients, and followed them for the incidence of stroke for an average of 41 months (range: 1-68 months, 1751 person-years). Results: MBPS was significantly correlated with the hsCRP level in patients with the highest quartile of MBPS, but not in the other quartiles. The odds ratio for silent cerebral infarcts (SCIs) was significantly higher only in patients in the highest quartile of MBPS with higher (above median) hsCRP [odds ratio 2.74, 95% confidence interval (CI) 1.42-5.30] in comparison with those in other quartiles of MBPS and with lower (below median) hsCRP. Conversely, being in the highest quartile of MBPS and having a higher hsCRP were independently and additively associated with an increased risk for clinical stroke events (both the highest quartile of MBPS and the higher hsCRP; hazard ratio [HR] 5.77, 95%CI 2.11-15.81, only the highest quartile of MBPS; HR 3.03, 95%CI 0.89-10.33, only the higher hsCRP; HR 2.89, 95%CI 1.12-7.47), even after adjusting for confounding factors. Conclusion: Exaggerated MBPS and increased low-grade inflammation independently increase the risk of stroke, while the relationship between exaggerated MBPS and the presence of SCIs is slightly affected by low-grade inflammation.