Reply to Professor Burattini's comments on “Exponentially tapered t-tube model of systemic arterial system in dogs”

摘要: There is no argument to say that the geometric and elastic tapering of arterial system rule nature any assumption describe mechanical anatomical properties blood vessels in a uniform fashion deviates considerably from reality. Diameter evident as lumen radius wall thickness become progressively small toward peripheral’. The stiffness pulse wave velocity are increasing with dis- tance heart. many reports sug- gesting reflection phenomena low-pass filteredz4. This low- pass filtering presumed be due geo- metric differences, such tapering, between proximal distal portions tree. Both diameter cause smooth change impedance will have substantial impact on magni- tude and/or sequence reflection. In studies “Wave travel arteries design cardiovascular system”, Taylor sum- marized main effects non-uniformity 5. These found efficiency enhanced if made less distensible its peripheral extensions. If heart frequency suitably chosen, non-uniform distensibility result minimal reflected components periphery functional isolation input impedance, thus both reducing cardiac work keeping it relatively constant at different fre- quencies. It was concluded experimental evidence all favour existence suitable mammalian system. Consequently, making use transmission line relate pulsatile pressure flow waveforms ascending aorta indeed improper. Burattini’s contribution uni- form model well recognized. However, scientific point view, important thing how advance issue remained unravelled incorporate geometrical vasculature analyse measured aortic signals. We start our approach by using an exponentially tapered tube6. process T-tube formu- lation, each tsbe terminates normalized lo&d &. Burattini et al. criticize & must real independent load equation (4). disagree comment because complex frequency-dependent, even tube. formulation line, not necessary concrete Z, has resistor. Therefore, r (0,) equals 0 tube terminal termination report6, we ologize for missing men- tion 1 F ‘I<< 1, when approxi- mation equation, (2), used resolve problem. question under ll?<< still big amplitude waves respect forward displayed Figure 4. fact, magnitude 0.48 calculated this value smaller than that, 0.55, estimated pro- posed aZ.‘,s, same dog data were analysed. Although shape these similiar those their T-tube, spectra inlet significantly models adopted