Blood vessel wall stiffening occurs in patients with impaired kidney function. Increased vessel rigidity is associated with cardiovascular problems. Vessel wall stiffness is measured using an ultrasound probe, placed over the artery, measuring changes in the dilation of blood vessels as the heart contracts. This is called pulse wave studies.
The Renal Department at Royal Perth Hospital are conducting an observational study across all treatment modalities of renal patients. This involves blood parameters and doing pulse wave studies 3 years apart. 87 patients assessed, 56% male, 65% Caucasian and 25% Australian Aboriginal (many from the North-West). 36% of renal disease was caused by diabetes, and 8% polycystic kidney disease.
The two main parameters are Pulse Wave Velocity (PWV) and Augmentation Index (AI). The AI, measured at the radial artery, is an indicator of arterial stiffness. Dependent on age and pulse rate. The PWV measures speed at which the waveform passes between the carotid and femoral arteries. The healthy range is between 5m/sec and 10m/sec. However, the range in the study was between 2 m/sec and 16 m/sec. A PWV over 10 m/sec involves a higher risk of cardiovascular disease. The average PWV in the study was 8.64 m/sec at baseline and 7.89 m/sec at the 3 year follow-up visit. This decrease may be explained by the reduction in numbers of those assessed due to 23 deaths and 15 lost to follow-up. Many of the patients not re-assessed had existing cardiovascular disease. Follow-up visits are continuing, so further analysis is needed.