Transaortic gradient is pressure-dependent in a pulsatile model of the circulation

J Heart Valve Dis. 1999 May;8(3):279-83.


Background and aim of the study: Although the transvalvular gradient is described as flow-dependent, pressure-dependence of the gradient, irrespective of flow, has not been demonstrated.

Methods: The Sheffield pulse duplicator equipped with a X-Cell 21 porcine valve mounted in the aortic position was used. Transaortic gradient was measured at a constant rate of 80 beats/min, while flow was kept at 2, 5 or 8 l/min, and systemic pressure was increased up to 200 mmHg by adjusting peripheral resistance manually. Valve area was computed with the Gorlin formula. A total of 87 measurements was carried out.

Results: For each flow, transvalvular gradient increased linearly with pressure, and computed area decreased. The slope of the pressure-gradient relationship was independent of flow.

Conclusion: Transaortic gradient depends not only on flow, but also shows pressure-dependency that should be taken into account when evaluating aortic stenosis, especially in hypertensive and hypotensive states.

MeSH terms

  • Aortic Valve / physiology*
  • Aortic Valve Stenosis / physiopathology
  • Coronary Circulation* / physiology
  • Humans
  • Models, Cardiovascular*
  • Pulsatile Flow*
  • Vascular Resistance*