The most common indication for cardiac surgical intervention is atherosclerotic coronary artery disease, often in the presence of impaired ventricular function. Available, techniques for predicting functional recovery of myocardium with revascularization are inadequate, particularly for the severely impaired ventricle in which the issue is most critical. A better means of assessing myocardial recoverability is apparent. Our laboratory has demonstrated that regional systolic strain and stress can be characterized using Magnetic Resonance Imaging (MRI)- based left ventricular (LV) geometrical data and advanced finite element modeling. Three-dimensional contour maps can then be generated from MRI images obtained at early systole, end-systole, and several intervals in between. We propose to test the clinical applicability and utility of these newly developed systolic indices, which we believe most accurately reflect systolic function at the cellular level, by characterizing the response to dobutamine on a regional basis before and after surgical revascularization. These methodologies promise more quantitative assessment of regional ventricular function in three dimensional space with greater resolution than currently available techniques. Specifically, we propose to test the hypotheses: (1) that a preoperative dobutamine-stimulated (low dose) improvement in systolic myocardial strand in myocardial regions with impaired resting systolic function is indicative of viability and therefore predictive of regional improvement in resting function after surgical revascularization; (2) that a preoperative absence of such an improvement is indicative of non-viability and therefore predictive of no regional improvement in resting function after surgical revascularization; and (3) that a preoperative high dose dobutamine-stimulated decrease in systolic myocardial strain in myocardial regions which are determined to be viable (as documented above) is predictive of regional improvement in high-dose dobutamine-stimulated function after surgical revascularization.
|Potter, D Dean; Araoz, Philip A; McGee, Kiaran P et al. (2008) Low-dose dobutamine cardiac magnetic resonance imaging with myocardial strain analysis predicts myocardial recoverability after coronary artery bypass grafting. J Thorac Cardiovasc Surg 135:1342-7|
|Potter, D Dean; Araoz, Philip A; Ng, Leong L et al. (2007) Cardiotropin-1 and myocardial strain change heterogeneously in cardiomyopathy. J Surg Res 141:277-83|
|Maniar, Hersh S; Cupps, Brian P; Potter, D Dean et al. (2004) Ventricular function after coronary artery bypass grafting: evaluation by magnetic resonance imaging and myocardial strain analysis. J Thorac Cardiovasc Surg 128:76-82|
|Moustakidis, Pavlos; Cupps, Brian P; Pomerantz, Benjamin J et al. (2004) Noninvasive, quantitative assessment of left ventricular function in ischemic cardiomyopathy. J Surg Res 116:187-96|