Thyroid hormones and arterial distensibility in man.

The findings on the effect of thyroid hormones on the metabolism of the vascular wall are presented. In 231 subjects with hyper- and hypofunction of the thyroid gland the arterial pulse propagation time (APPT) and the APPT index (APPT I) were examined as indirect indicators of arterial extensibility. Age-dependent reduction of APPT and APPT I was found in euthyroid subjects as well as hyper- and hypothyroid patients. In younger subjects aged 20--39 years the APPT interval was shorter in thyrotoxicosis and longer in hypothyroidism. The authors discuss the role of changes in the rate of blood flow and changes of the arterial media in the interpretation of these findings. The index of the left ventricular ejection time (LVET I) does not change with age in any of the examined groups. Changes of the arterial wall in higher age groups in man manifested by shortening of APPT were not influenced by increased or reduced thyroid function.