Relationship between preoperative viability and postoperative improvement in LVEF and heart failure symptoms

The presence of myocardial viability is predictive of improvement in region al left ventricular (LV) function after revascularization. Studies on predi cting improvement in global LV function are scarce, and the amount of viabl e myocardium needed for improvement in LV ejection fraction (LVEF) after re vascularization is unknown. Moreover, whether the presence of viability is associated with relief of heart failure symptoms after revascularization is uncertain. Hence, the aims were to define the extent of Viable myocardium needed for improvement in LVEF and to determine whether preoperative Viabil ity testing can predict improvement in heart failure symptoms. Methods: Pat ients (n = 47) with ischemic cardiomyopathy (mean LVEF +/- SD, 30% +/- 6%) undergoing surgical revascularization were studied with F-18-FDG SPECT to a ssess viability. Regional and global function were measured before and 3-6 mo after revascularization. Heart failure symptoms were graded according to the New York Heart Association (NYHA) criteria, before and 3-6 mo after re vascularization. Results: The number of viable segments per patient was dir ectly related to the improvement in LVEF after revascularization (r = 0.79, P < 0.01). Receiver operating characteristic curve analysis revealed that the cutoff level of four viable segments (representing 31% of the left vent ricle) yielded the highest sensitivity and specificity (86% and 92%, respec tively) for predicting improvement in LVEF. Furthermore, the presence of fo ur or more viable segments predicted improvement in heart failure symptoms after revascularization, with positive and negative predictive Values of 76 % and 71%, respectively. Conclusion: The presence of substantial viability (four or more viable segments, 31% of the left ventricle) on FDG SPECT is p redictive of improvement in LVEF and heart failure symptoms postoperatively .