Role of the sinuses of Valsalva on the opening of the aortic valve

Objective: The present in vitro study was designed to ascertain whether the presence of sinuses of Valsalva in the aortic root were able to regulate the valve effective orifice area and modulate the gradient across the valve independently from root compliance. Methods: Four different root configurations were prepared. Of the 4, 2 were silicon configurations with the same compliance, 1 with and 1 without sinuses of Valsalva, in which a 25-mm Solo stentless aortic valve was sutured inside. The other 2 configurations were obtained by substituting the upper part of the root with a straight Dacron graft or with a Valsalva graft in a remodeling fashion to reproduce the surgical situation. All roots were mounted in a pulse duplicator to measure the pressure decrease across the valve and effective orifice area at different cardiac outputs. Results: With increasing cardiac output up to 7 L/min, an increase in the pressure decrease across the valve was evident in both configurations without sinuses of Valsalva (7.90 +/- 1.7 and 11 mm Hg +/- 0.1 mm Hg, respectively) but not in those with sinuses (2.87 +/- 0.5 and 2.42 mm Hg +/- 0.5 mm Hg). Similarly, with increasing cardiac output, the effective orifice area increased significantly only in the roots with sinuses (5.13 +/- 0.5 and 5.47 +/- 0.5 vs 3.06 +/- 0.3 and 2.50 cm(2) +/- 0.02 cm(2), respectively). Conclusions: When the cardiac output is increased to greater than the resting physiologic values, the presence of sinuses of Valsalva, independently of root compliance, prevents an increase in the pressure decrease across the valve by way of an increase of the effective orifice area. (J Thorac Cardiovasc Surg 2013;145:999-1003)