Excerpt

For many years, imaging of myocardial viability in patients with CAD and severe left ventricular dysfunction was performed with either rest-redistribution Tl-201 SPECT imaging, nitrate-enhanced Tc-99m-sestamibi, or tetrofosmin rest imaging, PET imaging of perfusion and F-18-flurodeoxyglucose (FDG), or dobutamine echocardiography. All these techniques are clinically useful in predicting, with a fair degree of accuracy, which dyssynergic segments would show improvement in regional function after revascularization and which would not.1 A meta-analysis by Allman et al2 showed that the mortality rate was significantly higher in ischemic cardiomyopathy patients with substantial viable myocardium treated medically compared to those undergoing revascularization. The meta-analysis also showed that for patients with nonviable myocardium, revascularization seemed to have no survival benefit over medical therapy. It should be pointed out that the studies comprising this meta-analysis were observational in nature. Recently, Abraham et al3 reported the results of the Ottawa-FIVE substudy of the PET and Recovery Following Revascularization (PARR-2) trial in which patients with CAD and LV dysfunction were randomized to a PET-assisted management group or a standard care group. The decision to revascularize patients in the PET-assisted management group was based on showing viability by PET–FDG. This group had a 63% lower rate of cardiac death, MI, or rehospitalization in the first year during follow-up compared to the standard care group. The overall mortality was 7.5% in the PET arm and 14.8% in the standard arm. The sample size was too small to show a statistical significance for this difference, although the trend toward better survival was obvious. …