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Augmentation index assessed by applanation tonometry is elevated in Marfan Syndrome.

Payne RA, Hilling-Smith RC, Webb DJ, Maxwell SR, Denvir MA - J Cardiothorac Surg (2007)

Bottom Line: PP was not associated with aortic root size.However, when an independent GTF was used to derive carotid waves from radial waves, no differences were found in the degree of error between MFS and controls.Differences between MFS and controls in the nature of the peripheral-to-central GTF are present, although have little effect on the pulse contour.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK. r.payne@ed.ac.uk

ABSTRACT

Background: To examine whether augmentation index (AIx) is increased in Marfan syndrome (MFS) and associated with increased aortic root size, and whether a peripheral-to-central generalised transfer function (GTF) can be applied usefully in MFS.

Methods: 10 MFS patients and 10 healthy controls (matched for sex, age and height) were studied before and after 400 microg sub-lingual GTN. Arterial waveforms were recorded using applanation tonometry. AIx and pulse pressure (PP) were determined for the radial and carotid arteries. Pulse wave velocity (PWV) was measured between carotid and femoral arteries. GTFs were generated to examine the relationship between radial and carotid waveforms.

Results: AIx was greater in MFS compared to controls at radial (mean -31.4 (SD 14.3)% v -50.2(15.6)%, p = 0.003) and carotid (-7.6(11.2)% v -23.7(12.7)%, p = 0.004) sites. Baseline PP at all measurement sites, and PWV, did not differ between subject groups. Multivariate analysis demonstrated that PWV and carotid AIx were positively correlated with aortic root size (p < 0.001 and p = 0.012 respectively), independent of the presence of MFS. PP was not associated with aortic root size. GTN caused similar decreases in AIx in both controls and patients. Significant differences were found in GTFs between MFS and control subjects, which changed following GTN administration. However, when an independent GTF was used to derive carotid waves from radial waves, no differences were found in the degree of error between MFS and controls.

Conclusion: AIx is sensitive to the vascular abnormalities present in MFS, and may have a role as an adjunct to measurement of central PP and PWV. Differences between MFS and controls in the nature of the peripheral-to-central GTF are present, although have little effect on the pulse contour.

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Radial-to-carotid generalised transfer functions. Mean transfer functions shown in terms of mean gain and phase shift. Heavy lines, Marfan syndrome subjects; thin lines, controls; solid lines, pre-GTN baseline; broken lines, post-GTN.
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Figure 2: Radial-to-carotid generalised transfer functions. Mean transfer functions shown in terms of mean gain and phase shift. Heavy lines, Marfan syndrome subjects; thin lines, controls; solid lines, pre-GTN baseline; broken lines, post-GTN.

Mentions: Generalised transfer functions for baseline and post-GTN for both MFS and control subjects are shown in Figure 2. Before GTN, there were no significant differences between MFS and control in the lowest-frequencies at which the maximum negative phase shift occurred (2.2 ± 0.5 Hz vs. 2.0 ± 0.6 Hz respectively, p = 0.45) and greatest decrease in gain occurred (2.9 ± 0.9 Hz vs. 3.3 ± 1.1 Hz respectively, p = 0.41), or in AUC for gain (10.5 ± 3.1 vs. 8.1 ± 1.6 units.Hz, p = 0.09). Similar findings were observed after GTN. The AUC for phase was more negative for MFS than controls (-2.6 ± 2.1 vs. -0.8 ± 1.8 radians.Hz, p = 0.042) before GTN, although no significant differences were observed between subject groups after GTN. Following GTN administration, the lowest-frequency at which the maximum negative phase shift occurred decreased to 1.5 ± 0.4 in controls (p = 0.004) and 1.7 ± 0.5 in MFS (p = 0.001). The frequency at which the greatest decrease in gain occurred fell to 2.6 ± 0.4 Hz in controls (p = 0.017), and non-significantly in MFS (2.5 ± 0.7 Hz, p = 0.18). GTN had no significant effect on the gain or phase AUC for either controls or MFS.


Augmentation index assessed by applanation tonometry is elevated in Marfan Syndrome.

Payne RA, Hilling-Smith RC, Webb DJ, Maxwell SR, Denvir MA - J Cardiothorac Surg (2007)

Radial-to-carotid generalised transfer functions. Mean transfer functions shown in terms of mean gain and phase shift. Heavy lines, Marfan syndrome subjects; thin lines, controls; solid lines, pre-GTN baseline; broken lines, post-GTN.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2169245&req=5

Figure 2: Radial-to-carotid generalised transfer functions. Mean transfer functions shown in terms of mean gain and phase shift. Heavy lines, Marfan syndrome subjects; thin lines, controls; solid lines, pre-GTN baseline; broken lines, post-GTN.
Mentions: Generalised transfer functions for baseline and post-GTN for both MFS and control subjects are shown in Figure 2. Before GTN, there were no significant differences between MFS and control in the lowest-frequencies at which the maximum negative phase shift occurred (2.2 ± 0.5 Hz vs. 2.0 ± 0.6 Hz respectively, p = 0.45) and greatest decrease in gain occurred (2.9 ± 0.9 Hz vs. 3.3 ± 1.1 Hz respectively, p = 0.41), or in AUC for gain (10.5 ± 3.1 vs. 8.1 ± 1.6 units.Hz, p = 0.09). Similar findings were observed after GTN. The AUC for phase was more negative for MFS than controls (-2.6 ± 2.1 vs. -0.8 ± 1.8 radians.Hz, p = 0.042) before GTN, although no significant differences were observed between subject groups after GTN. Following GTN administration, the lowest-frequency at which the maximum negative phase shift occurred decreased to 1.5 ± 0.4 in controls (p = 0.004) and 1.7 ± 0.5 in MFS (p = 0.001). The frequency at which the greatest decrease in gain occurred fell to 2.6 ± 0.4 Hz in controls (p = 0.017), and non-significantly in MFS (2.5 ± 0.7 Hz, p = 0.18). GTN had no significant effect on the gain or phase AUC for either controls or MFS.

Bottom Line: PP was not associated with aortic root size.However, when an independent GTF was used to derive carotid waves from radial waves, no differences were found in the degree of error between MFS and controls.Differences between MFS and controls in the nature of the peripheral-to-central GTF are present, although have little effect on the pulse contour.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK. r.payne@ed.ac.uk

ABSTRACT

Background: To examine whether augmentation index (AIx) is increased in Marfan syndrome (MFS) and associated with increased aortic root size, and whether a peripheral-to-central generalised transfer function (GTF) can be applied usefully in MFS.

Methods: 10 MFS patients and 10 healthy controls (matched for sex, age and height) were studied before and after 400 microg sub-lingual GTN. Arterial waveforms were recorded using applanation tonometry. AIx and pulse pressure (PP) were determined for the radial and carotid arteries. Pulse wave velocity (PWV) was measured between carotid and femoral arteries. GTFs were generated to examine the relationship between radial and carotid waveforms.

Results: AIx was greater in MFS compared to controls at radial (mean -31.4 (SD 14.3)% v -50.2(15.6)%, p = 0.003) and carotid (-7.6(11.2)% v -23.7(12.7)%, p = 0.004) sites. Baseline PP at all measurement sites, and PWV, did not differ between subject groups. Multivariate analysis demonstrated that PWV and carotid AIx were positively correlated with aortic root size (p < 0.001 and p = 0.012 respectively), independent of the presence of MFS. PP was not associated with aortic root size. GTN caused similar decreases in AIx in both controls and patients. Significant differences were found in GTFs between MFS and control subjects, which changed following GTN administration. However, when an independent GTF was used to derive carotid waves from radial waves, no differences were found in the degree of error between MFS and controls.

Conclusion: AIx is sensitive to the vascular abnormalities present in MFS, and may have a role as an adjunct to measurement of central PP and PWV. Differences between MFS and controls in the nature of the peripheral-to-central GTF are present, although have little effect on the pulse contour.

Show MeSH
Related in: MedlinePlus