The effects of thyrotoxicosis and its treatment on central arterial stiffness.
OBJECTIVE
To assess central arterial stiffness in thyrotoxicosis using the technique of pulse wave analysis.


METHODS
Case control study designed to determine the effect of thyrotoxicosis on central arterial stiffness and at 6 months after radioiodine treatment.


METHODS
Twenty (18 women and 2 men) thyrotoxic patients and 20 age- and sex-matched controls were studied at baseline. Thyrotoxic patients were re-studied at 6 months following treatment of thyrotoxicosis with 555 MBq (131)I with no additional therapy for the six-month period.


METHODS
Using the sphygmocor apparatus, peripheral pressure waveforms were recorded non-invasively from the radial artery and central pressure waveforms were generated from these. Indices of arterial stiffness, central augmentation index (AI), augmentation of central arterial pressure (AG) and central blood pressures were derived. AI corrected for heart rate (AIc) was calculated.


RESULTS
Thyrotoxic patients recorded a significantly lower AI (means+/-s.e.m.) compared with controls (15.0+/-2.1 vs 28.0+/-2.1%; P<0.0005) even when corrected for differences in heart rate AIc (20.0+/-2.1 vs 28.0+/-2.1%; P<0.005) as well as AG (6.0+/-0.8 vs 10.0+/-1.1 mmHg; P<0.002) but higher pulse pressure (58.0+/-3.5 vs 47.0+/-2.0 mmHg; P<0.02). At 6 months following treatment, a significant rise in AIc (27.0+/-1.8 vs 20.0+/-2.1%; P<0.005) and AG (11.0+/-1.0 vs 6.0+/-0.8 mmHg; P<0.005) was noted. Lipid profiles were comparable between the groups.


CONCLUSIONS
These data suggested that subjects with untreated thyrotoxicosis have a decreased augmentation of central arterial pressure or lowered central arterial stiffness that would not appear to contribute to any excess cardiovascular risk in that condition.
Obuobie
K
K
Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF64 4XN, UK.
Smith
J
J
John
R
R
Davies
J S
JS
Lazarus
J H
JH
D001794:Blood Pressure / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology; D017534:Radial Artery / Q000503:physiopathology*; D011877:Radionuclide Imaging; D012044:Regression Analysis; D013971:Thyrotoxicosis / Q000000981:diagnostic imaging / Q000503:physiopathology*