Elastic properties of the young aorta: ex vivo perfusion experiments in a porcine model.
OBJECTIVE
To investigate the regional and directional compliance/distensibility of the healthy aorta.


METHODS
Complete fresh porcine aortas (n = 11) were perfused ex vivo under defined haemodynamic parameters using a custom-made pulse duplicator. Both circumferential and longitudinal compliance were measured optically.


RESULTS
The pulse duplicator was able to perfuse the entire aorta with arbitrary haemodynamic parameters, generating a physiological pulse curve. Aortic compliance is pressure dependent, as we observed a linear relationship between pressure and distension in the range of 5-200 mmHg; however, above 200 mmHg, the porcine aorta behaved in an inelastic manner. Circumferential compliance was highest in the ascending aorta (24%/100 mmHg) but significantly (P < 0.05) decreased in both the arch (18%/100 mmHg) and the descending aorta (15%/100 mmHg). Longitudinal compliance was highest in the ascending aorta and clearly exceeded circumferential compliance. Compliance was significantly (P < 0.05) higher in the outer curvatures of the ascending aorta and the aortic arch compared with the compliance of the inner curvature at these locations (30%/100 vs 23%/100 mmHg in the ascending aorta and 20%/100 vs 9%/100 mmHg in the arch, respectively).


CONCLUSIONS
Longitudinal compliance of the ascending aorta, particularly the outer curvature, is predominantly responsible for the 'Windkessel effect'. Pathological changes such as elongation and pronounced angulation of the ascending aorta increase stress on the outer curvature and may be important factors in the development of aortic dissection.
Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, Tübingen, Germany krueger-tobias@web.de.
Tobias
T
Krüger
Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, Tübingen, Germany.
Akvile
A
Grigoraviciute
Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, Tübingen, Germany.
Kujtim
K
Veseli
Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, Tübingen, Germany.
David
D
Schibilsky
Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, Tübingen, Germany.
Hans P
HP
Wendel
Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, Tübingen, Germany.
Wilke
W
Schneider
Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen, Tübingen, Germany.
Christian
C
Schlensak
D000818:Animals; D001011:Aorta / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D003187:Compliance / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D008953:Models, Anatomic; D011673:Pulsatile Flow / Q000502:physiology; D034421:Sus scrofa
Aorta; Aortic compliance; Aortic dissection