Estimation of Central Systolic Blood Pressure from Peripheral Pressure Waves using a Novel Second Systolic Pressure-Based Method in Normal and Heritable Hypercholesterolemic Rabbits

Fig.1. Examples of pressure waveform at the AA and right brachial artery in the normal (A) and KHC (B) rabbits at different MAP levels because of the intravenous infusion of vasoactive drugs. Ang II, angiotensin II; NTP, sodium nitroprusside; Control, before the administration of Ang II or NTP. Arrows represent the first peak/shoulder and second peak of the pressure waves at the asending aorta (AA) and brachial artery, respectively. Broken lines represent pSBP2. Pressure wave at the AA in the normal rabbit during the infusion of NTP shows the type B pattern.

Fig.2.. Correlation diagrams between cSBP and pSBP in the type A pattern (A) and type B pattern (D); between cSBP and pSBP2 in the type A pattern (B) and type B pattern (E); and between cSBP and pSBPm in the type A pattern (C) and type B pattern (F) in the normal and KHC rabbit groups

Fig.3. Correlation diagrams between cPP and pPP (A), between cPP and pPP2 (B), and between cPP and pPPm (C) in the normal and KHC rabbit groups. cPP correlated strongly with pPP, pPP2, and pPPm.

Fig.4. Correlation diagrams between ΔcPP and ΔpPP (A), between ΔcPP and ΔpPP2 (B), and between ΔcPP and ΔpPPm (C) in the normal and KHC rabbit groups. ΔcPP, ΔpPP, ΔpPP2, and ΔpPPm were the differences in cPP, pPP, pPP2, and pPPm before and after the administration of vasoactive drugs. ΔpPP, ΔpPP2, and ΔpPPm correlated significantly with ΔcPP in the two rabbit strains, except for ΔpPP in the KHC rabbit group.

Fig.5. Bland–Altman plots of the differences between pSBP and cSBP (A), between pSBP2 and cSBP (B), and between pSBPm and cSBP (C) against each average in the normal and KHC rabbit groups. Horizontal solid and dot-and-dash lines represent the mean bias and 1.96 SD between pSBP and cSBP (A), between pSBP2 and cSBP (B), and between pSBPm and cSBP (C) in the normal and KHC rabbit groups, respectively. A bold black line shows zero bias. The mean bias between pSBP and cSBP (±1.96 SD) was 5.7±7.5 and 3.8±8.9 for the normal and KHC rabbit groups, respectively. The mean bias between pSBP2 and cSBP (±SD) was –5.1±7.8 and −3.3±7.5 for the normal and KHC rabbit groups, respectively. By applying the average between pSBP and pSBP2 (pSBPm) instead of pSBP or pSBP2, the differences between pSBP and cSBP, and between pSBP2 and cSBP canceled each other. Consistent bias was minimized and distributed over a relatively narrow range around zero (0.3±4.7 and 0.2±5.3 for the normal and KHC rabbit groups, respectively).

Fig.6. Modified Bland–Altman plots depicting the difference between pSBP and cSBP (A), between pSBP2 and cSBP (B), and between pSBPm and cSBP (C) as the function of the peripheral augmentation index in the normal and KHC rabbit groups. P1 and P2 are the height of the early and late systolic waves, respectively. Horizontal solid and dot-and-dash lines represent the mean bias and 1.96 SD between pSBP and cSBP (A), between pSBP2 and cSBP (B), and between pSBPm and cSBP (C) in the normal and KHC rabbit groups, respectively. A bold black line shows zero bias. The mean bias between pSBP and cSBP (±1.96 SD) was 5.7±7.5 and 3.8±8.9 for the normal and KHC rabbit groups, respectively. The mean bias between pSBP2 and cSBP (±SD) was −5.1±7.8 and −3.3±7.5 for the normal and KHC rabbit groups, respectively. By applying the average between pSBP and pSBP2 (pSBPm) instead of pSBP or pSBP2, the negative and positive correlations canceled each other. The consistent bias (±1.96 SD) between pSBPm and cSBP was minimized and scattered over a relatively narrow range around zero (0.3±4.7 and 0.2±5.3 for the normal and KHC rabbit groups, respectively).