Long term prognostic value of myocardial viability and ischaemia during dobutamine stress echocardiography in patients with ischaemic cardiomyopathy undergoing coronary revascularisation

Objective: To evaluate the relative merits of viability and ischaemia for prognosis after revascularisation. Methods: Low - high dose dobutamine stress echocardiography (DSE) was performed before revascularisation in 128 consecutive patients with ischaemic cardiomyopathy ( mean (SD) left ventricular ejection fraction (LVEF) 31 (8)%). Viability ( defined as contractile reserve (CR)) and ischaemia were assessed during low and high dose dobutamine infusion, respectively. Cardiac death was evaluated during a five year follow up. Clinical, angiographic, and echocardiographic data were analysed to identify predictors of events. Results: Univariable predictors of cardiac death were the presence of multivessel disease ( hazard ratio (HR) 0.21, p< 0.001), baseline LVEF (HR 0.90, p< 0.0001), wall motion score index (WMSI) at rest (HR 4.02, p = 0.0006), low dose DSE (HR 7.01, p< 0.0001), peak dose DSE (HR 4.62, p< 0.0001), the extent of scar (HR 1.39, p< 0.0001), and the presence of CR in >= 25% of dysfunctional segments ( HR 0.34, p = 0.02). The best multivariable model to predict cardiac death included the presence of multivessel disease, WMSI at low dose DSE, and the presence of CR in >= 25% of the severely dysfunctional segments (HR 9.62, p< 0.0001). Inclusion of ischaemia in the model did not provide additional predictive value. Conclusion: The findings of the present study illustrate that in patients with ischaemic cardiomyopathy, the extent of viability ( CR) is a strong predictor of long term prognosis after revascularisation. Ischaemia did not add significantly in predicting outcome.