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The arterial reservoir pressure increases with aging and is the major determinant of the aortic augmentation index.

Davies JE, Baksi J, Francis DP, Hadjiloizou N, Whinnett ZI, Manisty CH, Aguado-Sierra J, Foale RA, Malik IS, Tyberg JV, Parker KH, Mayet J, Hughes AD - Am. J. Physiol. Heart Circ. Physiol. (2009)

Bottom Line: In 15 subjects (aged 53 +/- 10 yr), we measured pressure and Doppler velocity simultaneously in the proximal aorta using intra-arterial wires.With age, reservoir pressure increased progressively (9.9 mmHg/decade, r = 0.69, P < 0.001).Reservoir function rather than wave reflection changes markedly with aging, which accounts for the age-related changes in the aortic pressure waveform.

View Article: PubMed Central - PubMed

Affiliation: International Centre for Circulatory Health, St. Mary's Hospital & Imperial College, 59-61 N. Wharf Rd., Paddington, London, W2 1LA, UK. justin.davies@imperial.ac.uk

ABSTRACT
The augmentation index predicts cardiovascular mortality and is usually explained as a distally reflected wave adding to the forward wave generated by systole. We propose that the capacitative properties of the aorta (the arterial reservoir) also contribute significantly to the augmentation index and have calculated the contribution of the arterial reservoir, independently of wave reflection, and assessed how these contributions change with aging. In 15 subjects (aged 53 +/- 10 yr), we measured pressure and Doppler velocity simultaneously in the proximal aorta using intra-arterial wires. We calculated the components of augmentation pressure in two ways: 1) into forward and backward (reflected) components by established separation methods, and 2) using an approach that accounts for an additional reservoir component. When the reservoir was ignored, augmentation pressure (22.7 +/- 13.9 mmHg) comprised a small forward wave (peak pressure = 6.5 +/- 9.4 mmHg) and a larger backward wave (peak pressure = 16.2 +/- 7.6 mmHg). After we took account of the reservoir, the contribution to augmentation pressure of the backward wave was reduced by 64% to 5.8 +/- 4.4 mmHg (P < 0.001), forward pressure was negligible, and reservoir pressure was the largest component (peak pressure = 19.8 +/- 9.3 mmHg). With age, reservoir pressure increased progressively (9.9 mmHg/decade, r = 0.69, P < 0.001). In conclusion, the augmentation index is principally determined by aortic reservoir function and other elastic arteries and only to a minor extent by reflected waves. Reservoir function rather than wave reflection changes markedly with aging, which accounts for the age-related changes in the aortic pressure waveform.

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Relationship between separated pressure components and aging after accounting for the aortic reservoir pressure. The pressure waveform was separated into forward (A) and backward (B) and reservoir (C) pressure components. With increasing age, both forward and arterial reservoir pressure increased. However, the backward pressure component was not significantly correlated with age.
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Figure 4: Relationship between separated pressure components and aging after accounting for the aortic reservoir pressure. The pressure waveform was separated into forward (A) and backward (B) and reservoir (C) pressure components. With increasing age, both forward and arterial reservoir pressure increased. However, the backward pressure component was not significantly correlated with age.

Mentions: We applied the same analysis over the entire pressure waveform to assess the changes in forward, backward, and reservoir pressures that occur with age. The whole group included subjects with characteristically different-shaped pressure waveforms (i.e., type A, type B, and type D beats) (2). The augmentation pressure and AIx both increased with aging. When the aortic reservoir was ignored, both the forward and backward pressures increased with aging (Table 3). However, when the aortic reservoir was accounted for, the forward pressure continued to increase with aging (Table 3, and Fig. 4A) but the backward pressure was no longer found to increase (Table 3, and Fig. 4B). The reservoir pressure was found to markedly increase with aging (Table 3, and Fig. 4C). These findings are essentially identical when applied using either pulse pressure or systolic pressure waveforms.


The arterial reservoir pressure increases with aging and is the major determinant of the aortic augmentation index.

Davies JE, Baksi J, Francis DP, Hadjiloizou N, Whinnett ZI, Manisty CH, Aguado-Sierra J, Foale RA, Malik IS, Tyberg JV, Parker KH, Mayet J, Hughes AD - Am. J. Physiol. Heart Circ. Physiol. (2009)

Relationship between separated pressure components and aging after accounting for the aortic reservoir pressure. The pressure waveform was separated into forward (A) and backward (B) and reservoir (C) pressure components. With increasing age, both forward and arterial reservoir pressure increased. However, the backward pressure component was not significantly correlated with age.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2822572&req=5

Figure 4: Relationship between separated pressure components and aging after accounting for the aortic reservoir pressure. The pressure waveform was separated into forward (A) and backward (B) and reservoir (C) pressure components. With increasing age, both forward and arterial reservoir pressure increased. However, the backward pressure component was not significantly correlated with age.
Mentions: We applied the same analysis over the entire pressure waveform to assess the changes in forward, backward, and reservoir pressures that occur with age. The whole group included subjects with characteristically different-shaped pressure waveforms (i.e., type A, type B, and type D beats) (2). The augmentation pressure and AIx both increased with aging. When the aortic reservoir was ignored, both the forward and backward pressures increased with aging (Table 3). However, when the aortic reservoir was accounted for, the forward pressure continued to increase with aging (Table 3, and Fig. 4A) but the backward pressure was no longer found to increase (Table 3, and Fig. 4B). The reservoir pressure was found to markedly increase with aging (Table 3, and Fig. 4C). These findings are essentially identical when applied using either pulse pressure or systolic pressure waveforms.

Bottom Line: In 15 subjects (aged 53 +/- 10 yr), we measured pressure and Doppler velocity simultaneously in the proximal aorta using intra-arterial wires.With age, reservoir pressure increased progressively (9.9 mmHg/decade, r = 0.69, P < 0.001).Reservoir function rather than wave reflection changes markedly with aging, which accounts for the age-related changes in the aortic pressure waveform.

View Article: PubMed Central - PubMed

Affiliation: International Centre for Circulatory Health, St. Mary's Hospital & Imperial College, 59-61 N. Wharf Rd., Paddington, London, W2 1LA, UK. justin.davies@imperial.ac.uk

ABSTRACT
The augmentation index predicts cardiovascular mortality and is usually explained as a distally reflected wave adding to the forward wave generated by systole. We propose that the capacitative properties of the aorta (the arterial reservoir) also contribute significantly to the augmentation index and have calculated the contribution of the arterial reservoir, independently of wave reflection, and assessed how these contributions change with aging. In 15 subjects (aged 53 +/- 10 yr), we measured pressure and Doppler velocity simultaneously in the proximal aorta using intra-arterial wires. We calculated the components of augmentation pressure in two ways: 1) into forward and backward (reflected) components by established separation methods, and 2) using an approach that accounts for an additional reservoir component. When the reservoir was ignored, augmentation pressure (22.7 +/- 13.9 mmHg) comprised a small forward wave (peak pressure = 6.5 +/- 9.4 mmHg) and a larger backward wave (peak pressure = 16.2 +/- 7.6 mmHg). After we took account of the reservoir, the contribution to augmentation pressure of the backward wave was reduced by 64% to 5.8 +/- 4.4 mmHg (P < 0.001), forward pressure was negligible, and reservoir pressure was the largest component (peak pressure = 19.8 +/- 9.3 mmHg). With age, reservoir pressure increased progressively (9.9 mmHg/decade, r = 0.69, P < 0.001). In conclusion, the augmentation index is principally determined by aortic reservoir function and other elastic arteries and only to a minor extent by reflected waves. Reservoir function rather than wave reflection changes markedly with aging, which accounts for the age-related changes in the aortic pressure waveform.

Show MeSH
Related in: MedlinePlus