Abstract 3192: Identification of High Risk Patients with Ischemic Cardiomyopathy using FDG PET
Purpose: Patients with ventricular dysfunction and coronary disease may benefit from revascularization, but not without risk. F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) imaging can detect viable myocardium that may recover after revascularization. In the PARR-2 trial, the outcome benefit of FDG PET imaging did not reach statistical significance. We sought to identify which patients, based on FDG PET parameters, would benefit from revascularization.
Methods: Inclusion criteria were an EF <35%, known CAD, no MI within 4 weeks. For this substudy, we considered the PET arm of the study. Of 218 patients randomized to PET, 195 had complete and interpretable data including FDG PET and baseline ejection fractions. The primary outcome was a composite of cardiac death, MI, transplantation or cardiac hospitalization at one year. In order to investigate the effect of hibernation and protocol revascularization on the primary outcome in PET arm patients, multivariable Cox proportional hazard models were used. Interaction hazard ratios at various levels of mismatch are provided to show the effect more clearly.
Results: In the multivariable adjusted model, those with lower levels of mismatch (mismatch =1%) the risk of the primary outcome is no different if revascularization is done or not done (Table I⇓). At higher levels of mismatch (mismatch =9%) the risk of the composite event decreases by 60% if revascularization is done compared to not done (revasc and mismatch interaction p=0.026).. Increasing creatinine (HR 1.004, 95% CI:1.001,1.006, p=0.003) and EF (HR 0.95, 95% CI:0.92,0.99, p=0.022) were other independent predictors of the primary outcome.
Conclusion: Patients with ischemic cardiomyopathy with larger amounts of hibernation had improved outcome with revascularization. Further independent predictors of outcome were renal function and EF. FDG PET appears useful in defining a subgroup that could gain significant benefit from revascularization.