Background: Apico-aortic conduit (AAC) implantation is an effective surgery in relieving complex left ventricular outflow obstruction. We compared the echocardiographic parameters associated with cardiac function and hemodynamics between before and after the procedure.
Methods: Echocardiographic examination, including end-diastolic dimension and ejection fraction of left ventricle, aortic valve area, left ventricular-to-aortic pressure gradient and stroke volume, was conducted before and after AAC implantation in nine patients (1 male, 8 female; 80±6 years old) with aortic stenosis at our institution between 2001 and 2006. Stroke volume was derived from flow curve obtained from sampling sites placed on left ventricular outflow tract and conduit. All patients were symptomatic, and two patients had manifested cardiogenic shock.
Results: All patients had markedly calcified and stenotic aortic valve with an area of 0.5±0.1 cm². After the procedure, chest symptoms had markedly improved in all patients. The left ventricular-to-aortic pressure gradient significantly decreased after the procedure (23±7 mmHg; p<0.001) compared with that before the procedure (115±34 mmHg). In addition, there was no significant difference between the flow velocity at the aortic valve and the prosthetic valve on conduit. The differences of the ejection fraction and the end-diastolic dimension of the left ventricle between before and after the procedure were not significant. Cardiac outflow (3.46±0.79 l/min) through the conduit was 80±3% of the total cardiac output.
Conclusion: The present study showed that a major part of the cardiac outflow was through the conduit in patients with aortic stenosis who underwent AAC implantation. This finding supports that AAC implantation is an effective surgery for aortic stenosis in addition to traditional aortic valve replacement.

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