Previous measurement methods — Missing the target
Why the limited view of conventional cardiovascular diagnostics is at the expense of therapeutic success and patient health.
Previous measurement methods
Missing the target
Take the most circuitous route thinkable: The traditional approach used so far to determine arterial stiffness.
This is not an exaggeration — it accurately describes daily cardiovascular diagnosis routines. Everything revolves around measurement data that are beyond any doubt. But where clarity, unambiguousness, and the highest precision of the values measured would be of the highest importance to prevent and treat cardiovascular damage and secondary diseases, circuitous surrogate parameters prevail. Often, these parameters poorly reflect the true condition of the arteries and give an inadequate, often even error-prone account of the individual cardiovascular status.
The underlying problem lies in the general difficulty of obtaining reliable vascular data: The wall properties of arteries cannot easily be determined directly in living humans.
This limitation becomes even more important when it comes to the functioning of an entire arterial tree. However, it would be particularly important to be able to analyze this in detail: Namely, to clarify, depending on the individual case, how energy-efficiently and evenly — or not — the blood transport to the respective organs takes place. Based on this, conclusions can be drawn about the respective physical properties of the heart and arteries and any risks.
The shortcoming of traditional diagnostics
The principle of conventional pulse wave analysis is based on identifying the arterial/cardiovascular properties of a patient by the shape of the pulse wave. With this approach, the specific condition of the vessels in each case can be read primarily from the stiffness of the arterial walls: The lower their elasticity due to deposited plaques, the higher the risk of life-threatening cardiovascular events such as heart attack or stroke in particular. It is also possible to extrapolate from the pulse waveform to the central blood pressure, i.e. the aortic pressure.
The crucial weakness of all traditional measurement methods is the exclusively indirect determination of arterial stiffness via surrogate parameters such as pulse wave velocity (PWV), augmentation index (AIX), or flow-mediated dilation (FMD). These parameters are predominantly based on different methodological variants, all of which measure the pulse wave waveform at the upper arm, wrist, or finger. The surrogate parameters thus obtained then provide the measure of the elasticity or stiffness of the arteries.
However, due to the roundabout determination, the accuracy and traceability of the values fall by the wayside. In addition, these auxiliary parameters often report limitations in arterial distensibility, which is the most sensitive marker of arterial function, much too late, i.e., only when the first signs of disease are already apparent. In addition, the Doppler method, for example, which is often used in the context of pAVK screening, only ever records arterial pressure selectively, i.e. related to a single artery. This can lead to a false picture of the actual condition of the arteries — in the worst case, narrowings (stenoses) are overlooked. Thus, most of the conventional approaches to measurement data acquisition fall short of the task at hand, which is early diagnosis and prevention of cardiovascular disease.
In contrast to the previous, deficient diagnostic standard, individually tailored, model-based pulse wave analysis can be used to determine a whole range of new parameters that not only provide unrivaled detailed insight into the vascular status of patients but also offer added value in terms of effective prevention of cardiovascular events. These include pressures that can be measured directly in the model, particularly aortic pressure (cBP). More about the new parameters.