The Relationships between the Differences in the Central Blood Pressure and Brachial Blood Pressure and Other Factors in Patients with Essential Hypertension

Abstract

Objective The management of blood pressure (BP) in hypertensive patients is the key to preventing a progression of organ damage. The brachial BP (bBP) has been used as the representative method for measuring the BP. The central BP (cBP), which is, different from the bBP due to the propagation and the reflection of the pulse wave in the arterial system, has recently received attention because it can now be estimated non-invasively. We examined the relationships between the difference in the central systolic BP (csBP) and the brachial systolic BP (bsBP) (Δ) and other factors in hypertensive patients. Methods The bsBP and csBP were measured in patients with essential hypertension and the relationships between the bsBP, csBP, or Δ and background factors including age, the brain natriuretic peptide (BNP) level, the estimated glomerular filtration rate (eGFR), flow-mediated vasodilation (an index of vascular endothelial function), the cardio-ankle vascular index (CAVI, an index of arteriosclerosis), and the carotid intima-media thickness (an index of atherosis) were investigated. Results The data of 191 patients were analyzed. Although there was no significant correlation between the CAVI and the bsBP; positive correlations were observed between the CAVI and the csBP (r=0.249, p=0.001). The Δ value showed significant positive correlations with age, and the BNP, eGFR, and CAVI values. Conclusion The csBP is more strongly associated with arteriosclerosis than the bsBP. Moreover, the Δ value is more strongly associated with cardiac function, renal function, and arteriosclerosis than the bsBP or csBP. These data suggested that the Δ value may have a greater prognostic value than the bsBP or csBP and may be worth calculating in the clinical setting.

Figure 1.

The peripheral and central pulse waveform patterns. (a) The peripheral (radial) pulse waveform showing the peripheral systolic pressure (P1) and peripheral late systolic shoulder (P2, SBP2), which were used to calculate the augmentation index. The dashed line shows the SBP2, which corresponded to the central systolic blood pressure (csBP). (b) The central (aortic) waveform showing the csBP. Both waves are consistent with the description of Richardson et al. (28). sBP: systolic blood pressure, DBP: diastolic blood pressure

Figure 2.

Scattergrams showing the relationships between age and the blood pressure data. The correlation between age and (a) the bsBP; y=0.2607x+122.56, (b) csBP, (c) SBP2, (d) Δ (csBP-bsBP); y=0.1946x-7.311, and (e) PP; y=0.3088x+36.284. bsBP: brachial systolic blood pressure, sBP: systolic blood pressure, csBP: central systolic blood pressure, Δ: central systolic blood pressure-brachial systolic blood pressure, PP: pulse pressure, SBP2: pressure of the late systolic shoulder