Effect of hormone replacement therapy on non-invasive cardiovascular haemodynamics.

ABSTRACT

OBJECTIVE: To determine the detailed effects of hormone replacement therapy (HRT) on non-invasive haemodynamics, including an assessment of the effect on the pulsatile afterload assessed in terms of the augmentation index and pulse-wave velocity. DESIGN: A cross-sectional study of healthy postmenopausal women using carotid and radial tonometry and pulse-wave velocity measurements. SETTING: Community-based ambulatory women attending the menopause centre at a tertiary hospital. PATIENTS Seventy postmenopausal women divided into those not currently being administered HRT (n = 38, aged 46-72 years) and those who were being administered a variety of HRT (n = 32, aged 49-67 years). METHODS: Central arterial pressure waveforms were measured using carotid applanation tonometry to derive the augmentation index and ejection duration. The arterial pulse-wave velocity was assessed using paired carotid, radial and dorsalis tonometry waveforms. RESULTS: Women being administered HRT had a significantly lower augmentation index (20.4 +/- 8.6 versus 27.0 +/- 10.2%, P = 0.005) and shorter ejection times (320 +/- 17 versus 329 +/- 18 ms, P = 0.037). There was no significant difference in brachial blood pressure (131/76 versus 129/77 mmHg). Women being administered HRT exhibited a greater reversal in the age-related loss of amplification which occurs owing to arterial stiffening. This amplification between central and peripheral systolic blood pressures was greater among women being administered HRT (5.3 +/- 6.2 versus 2.2 +/- 4.0 mmHg, P = 0.014). There was no difference in pulse-wave velocity between the two groups. CONCLUSIONS: HRT appears to improve the pulsatile vascular afterload by decreasing the augmentation of the late systolic blood pressure. This effect is not apparent from routine brachial cuff measurements, which, as a result, may underestimate haemodynamic benefits. Such effects may help to explain a portion of the improvement in cardiovascular morbidity found in other trials.