Arterial Stiffness in women, during the menopausal transition and beyond, as a predictor of cardiovascular disease: a twelve-year followup to assess the contribution of hormonal factors in a representative sample of urban Australian women

The proposed study will replicate a previous cross-sectional study of the relationship between menopause status and arterial stiffness in a subset of a multidisciplinary assessment of the effects of ageing in women. The results of the cross-sectional study (see earlier citation) demonstrated that ageing was the factor most strongly associated with increasing aortic stiffness. Menopause, per se, did not appear to alter gradual age-dependent changes in arterial stiffness. However, this study was limited by its five-year time span, and the numbers of women who were approaching the menopausal transition at the time of the study This replication will involve re-testing the same sample of women twelve years after their initial assessment when all pre-menopausal women in the original sample will almost certainly have entered or passed through the menopausal transition. The retest procedure should take approximately one hour to complete and was conducted in the Betty Byrne Henderson Women's Health Research Centre, Royal Brisbane Women's Hospital Herston, QLD. Brachial systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured in the sitting position after approximately 5 minutes of rest using a mercury sphygmomanometer. BP measurement was recorded as an average of three readings at two-minute intervals. Arterial stiffness (pulse wave velocity and pulse wave analysis) was measured non-invasively (using SphygmoCor® technology). All assessments were undertaken by the same specially trained registered nurses using the same equipment. SBP and DBP were entered into the SphygmoCor software to allow for calibration of the radial pressure waveform. Height, weight, body mass index (BMI), details of medical history, family history of diabetes and cardiovascular disease (CVD), smoking history, menopause status, use of cardiovascular medication and hormone therapy were also entered into the SphygmoCor database. All participants were studied in the supine position. Radial artery waveforms were recorded in all subjects with a high-fidelity tonometer (Millar Instruments, Houston, Texas) from the right wrist. Pulse wave analysis (SphygmoCor version CvMSV9. AtCor Medical Pty Ltd., Sydney, Australia) was used to generate a corresponding central waveform with a generalized transfer function, which has been validated against invasive recordings of the aortic pressure wave. Four or five studies of pulse wave analysis (PWA) were collected from each subject, and the mean values used in the subsequent analysis. Only studies with a quality index of over 90% were accepted. With the SphygmoCor software, Augmentation Pressure (AP) is calculated as the difference between the second and first systolic peaks, and Augmentation Index calculated as AP expressed as a percentage of the pulse pressure (PP). The aortic pulse wave velocity (PWV) was measured with the same machine, at the femoral (site A) and carotid (site B) arteries with simultaneous electrocardiograph (ECG) using the Lead II ECG configuration. PWV distance was measured (in millimeters) superficially by subtracting the distance between the carotid site and the suprasternal notch from the distance between the suprasternal notch (via the umbilicus) and the femoral site.