The power combination of blood-pressure parameters to predict the incidence of plaque formation in carotid arteries in elderly.

Hypertension is considered as one of the major risk factors of atherosclerosis, especially for carotid artery plaque, which is a sign for cardiovascular incapacity and cerebral infarction. As adult age, systolic blood pressure (SBP or S) tends to rise and diastolic blood pressure (DBP or D) tends to fall, thus the pulse pressure (PP) will increase. The vascular injury was directly proportional to the level of SBP, and inversely proportional to DBP. But so far, studies of the vascular injury based on SBP and DBP measurement were mostly qualitative. The exact contribution of each parameter to the vascular injury has not been quantitatively identified. In this study, we employed a mathematical model to predict the risk for plaques of carotid arteries in aged people and combined the SBP, DBP and heart rate (HR) to perform a quantitative analysis. We analyzed 1672 males who were over 60-year-old and hospitalized due to atherosclerosis-related diseases and received a 24-h arterial blood pressure monitoring (ABPM) examination. These patients were divided into 19 subgroups using the ABPM data, 24-h average SBP, DBP and HR as variables based on the ascending order of the magnitude of each element. We developed a new index, namely the dynamic level (DL) which correlated best with the plaque formation of carotid arteries among all the well-established indexes for blood pressure. We demonstrated that index DL has better correlation to plaques incidence tendency (p < 0.0001) when compared to either SBP (P < 0.05) or PP (P < 0.001) alone. The risk on incidence of the plaques of carotid arteries has positive correlation with first power of SBP and -0.8 power of DBP. This model can be used clinically to predict the occurrence of plaque formation.