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This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 103/1/66    most recent 00664.2006v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Burattini, R. Articles by Di Salvia, P. O. Search for Related Content PubMed PubMed Citation Articles by Burattini, R. Articles by Di Salvia, P. O.

Development of systemic arterial mechanical properties from infancy to adulthood interpreted by four-element windkessel models

¹Department of Electromagnetics and Bioengineering, Polytechnic University of Marche, Ancona, Italy; and ²Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, Washington

Submitted 12 June 2006 ; accepted in final form 6 February 2007

Aortic impedance data of infants, children and adults (age range 0.8–54 yr), previously reported by others, were interpreted by means of three alternative four-element windkessel models: W4P, W4S, and IVW. The W4P and W4S are derived from the three-element windkessel (W3) by connecting an inertance (L) in parallel or in series, respectively, with the aortic characteristic resistance (R_c). In the IVW, L is connected in series with a viscoelastic windkessel (VW). The W4S and IVW (same input impedance) fit the data best. The W4S, however, suffers from the assumption that R_c is part of total peripheral resistance (R_p). The IVW model offers a new paradigm for interpretation of resistive properties in terms of viscous (R_d) properties of vessel wall motion, distinguished from R_p. Results indicated that rapid reduction of R_d/R_p during early development is functional to modulation of decay time constant (_d) of pressure in diastole, such that normalization over heart period (_d/T) is independent of body size. Estimates of total arterial compliance (C) vs. age were fitted by a bell-shaped curve with a maximum at 33 yr. With body weight (BW) factored out by normalization, the C/BW data scattered about a bell-shaped curve centered at 66 mmHg. Inertance was significantly higher in pediatric patients than in adults, in accordance with a lower cross-sectional area of the vasculature, commensurate to a lower aortic flow. Changes of arterial properties appear functional to control the ratio of pulsatile power to active power and keep arterial efficiency as high as 97% in infants and children.

arterial compliance; arterial inertance; aortic input impedance; viscoelasticity; viscoelastic windkessel