Blood pressure and pulse wave measuring combined is a simple method for assessing the damage to or health of the vascular system. The measurement is taken by means of the known standard examination using a blood pressure cuff on the upper arm and is equally accessible to both patients and doctors. The measurement is recommended by the DeGAG (Deutsche Gesellschaft für arterielle Gefäßsteifigkeit, the German Association for Arterial Stiffness) and the Artery and European Society of Hypertension specialist companies for examining and treating high blood pressure.
Scientific knowledge shows that arterial stiffness is more predictive in terms of prognosis than blood pressure monitoring alone.
Each contraction of the left ventricle generates a pulse wave. Stiffening in the arterial vessel walls leads to early wave reflection in the systole and is therefore associated with an increase in pressure in the central aorta. Increased central blood pressure means an unfavourable rise in cardiac afterload, a reduction in diastolic coronary flow and myocardial microcirculation. This may result in damage to other organs such as the kidneys and brain.
Several studies have now been able to show the prognostic benefits of central blood pressure in comparison to peripheral blood pressure. As a result, in the event of increased central blood pressure an increased cardiovascular risk may be assumed, even if the peripherally measured blood pressure is within the normal range.
The central blood pressure reflects the heart afterload. An increase in central blood pressure values indicates an increase in the left ventricular mass (LVH - left ventricular hypertrophy). LVH correlates better with co-morbidity, e.g. arrhythmias (atrial fibrillations), proteinuria and stroke.
Arterial stiffness is quantified using pulse wave velocity (PWV) with m/s as the unit of measurement.
The prognostic value of arterial stiffness in relation to cardiovascular diseases (e.g. stroke) is substantiated and is more important than the classic risk factors such as high blood pressure, Framingham risk score and hypercholesterolaemia.
All antihypertensive classes of substances reduce blood pressure in a similar way. Their hemodynamic features differ in terms of heart rate, stroke volume, and peripheral resistance however. Pulse wave analysis provides information about the individually measured stroke volume and peripheral resistance. Certain antihypertensives lead to a reduction in the peripheral vascular resistance which leads to the heart function easing (afterload) and the stroke volume improving at the same time. The randomised intervention study by R.D. Smith et al. shows that therapy decisions based on measured hemodynamics (stroke volume and peripheral resistance) achieve up to 69% better accuracy in the blood pressure adjustment with the initial prescription.
PWV and central systolic pressure are measured tonometrically or using oscillometric systems. In theory, it should be possible to measure blood pressure and pulse wave analysis combined (blood pressurePWA measurement). The accuracy of the measurement should be tested against invasive catheter technology and published. The Mobil-O-Graph® PWA monitor has been comprehensively assessed against the catheter, and the results have been published in a number of international journals.