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.