Abstract
In this thesis we have explored different aspects of blood pressure measurement and related it to the risk of cardiovascular disease.
In the first part we showed that when the arm is positioned under heart level, for example when the arm is placed on a desk or a chair support, the blood pressure and the cardiovascular risk is overstimated. We demonstrated that crossing the legs at the level of the knee, but not at the level of the ankle, causes a rise of blood pressure. We proved that the physiological mechanism causing the blood pressure rise was a rise in stroke volume and cardiac output.
In the second part, we have investigated the separate contribution of the hospital environment and the presence of the physician on the white coat effect (a higher blood pressure at home, than in the hospital in the presence of a doctor). We concluded that the hospital environment had a larger influence on the white coat effect than the presence of a physician. We also reviewed the present literature regarding diagnostic and therapeutic thresholds of the self-measured blood pressure at home and proposed new cut-off values for optimal, normal and high cardiovascular risk.
In the third and last part we reviewed and explored a new index for arterial stiffness (the ambulatory arterial stiffness index, AASI). Arterial stiffness marks the ageing of arteries and is a precursor and marker of cardiovascular disease. The AASI is determined by simple 24-hour blood pressure monitoring. We studied the reproducibility of the AASI and concluded that is was as reproducible as other ambulatory markers of cardiovascular risk. We have set quality criteria for the AASI and demonstrated that this new index is ready to be used in cardiovascular risk stratification on a large scale.
