A variety of pathologic processes can cause incompentence of heart valves. Depending on the extent of such
disorders, valve incompentence can result in severe cardiac disease causing symptoms of heart failure and
evtentually death. For adequate treatment of valve incompetence accurate diagnositic tools - possibly noninvasive
techniques - that do not only provide the diagnosis of incompentence but also accuatre quantification are crucial.
Despite intensive research efforts, no generally excepted method has so far been developed for this purpose. Based
on clinical investigation, measurements of the regurgitant jet through the incompetent valve at its narrowest part
close to the valve defect - the so called vena contracta - have gained particular interest. However, clinical studies
with the lack of a proper gold standard for comparison cannot sufficiently validate such quantification methods.
Therefore, we developed a well control in-vitro flow model that allows simulation of valve incompetence. Doppler
ultrasound, direct flow and pressure measurements as well as laser flow visualization can simultaneously be
performed. Our extensive studies demonstrate that color Doppler measurements provide a very rough estmiate of
the true vena contracta, only. Measurements by Doppler ultrasound markedly overestimate the vena contracta and
are in addition affected by other variable such as flow rate which is not the case for the true vena contracta. All
together, the results indicate that Doppler ultrasound by this method does not provide real quantitatve data.
Nevertheles, categories of disease severity (mild and moderate vs. severe valve incompetence) can in general by
distinguished. For certain clinical purposes, the method can, thus, indeed be helpful as a semiquantitative
technique.