Abstract 19424: Off-pump Left Ventricular Apical to Descending Aortic Conduits in Adults with Aortic Stenosis: Postoperative Cardiodynamic Evaluation with Cardiac Magnetic Resonance Imaging
Background: Off-pump apico-aortic conduit (AAC) is an alternative to aortic valve replacement in select adult patients with a hostile mediastinum; however, the resulting changes in blood flow have not been defined. The objective of this study is to evaluate the postoperative cardiodynamics of patients with AAC.
Methods: A retrospective review of 11 patients undergoing AAC from 2009–2010 at a US academic center was performed. Transthoracic echocardiography was used to assess preoperative hemodynamics of the native aortic valve. Postoperatively, cardiac MRI was performed on a Philips 1.5T Achieva system. Hemodynamic data was collected using gated phase contrasted velocity mapping of the aorta and the conduit. Left ventricular stroke volume was obtained from CINE SSFP short axis slices. The data was processed using an offline workstation.
Results: Mean age was 75.6±3.8 yrs (median: 77.8) and 6 patients (54.5%) were male. Preoperative EF was 50±8% (median: 55), and preoperative aortic valve (AV) area was 0.81±0.17cm2 (median: 0.82). The mean flow per beat through the conduit was 50.1±7.3mL (median: 51.0). When related to the patients' stroke volumes, the blood flow through the conduit comprised a mean of 58±7% (median: 59) of the stroke volume. When mitral regurgitation was excluded and only the flow through the native valve and conduit was compared, the conduit comprised a mean of 71±8% (median: 75) of forward flow. There was a direct correlation between preoperative AV area and the percent of forward flow through the conduit; AV area was found to be inversely proportional to the percent of flow through the conduit (R2= 0.84, Figure 1). Three patients had repeat MRI at 6 months, with no change in cardiodynamics.
Conclusions: Blood flow through the conduit accounts for the majority of forward flow in patients with severe AS and AAC. This novel study demonstates that there is an inverse relationship between preoperative AV area and the relative amount of flow through the conduit.
- © 2010 by American Heart Association, Inc.