Myocardial viability: strengthening the evidence base

Excerpt

Over three decades ago, the concept of myocardial hibernation arose from the observation that chronically dysfunctional myocardium could recover function with re-vascularization [1]. Since then, a variety of techniques [2, 3] have been developed for the detection of myocardial viability, ranging from nuclear imaging to dobutamine echocardiography, positron emission tomography (PET) and, more recently, late gadolinium contrast enhancement with magnetic resonance imaging. Despite the availability of such a wide array of tools, defining the optimal approach for viability testing in the management of coronary artery disease continues to be challenging. The most widely accepted ‘gold standard’ for viability is PET, but it is more costly and not as widely available as single-photon emission computed tomography (SPECT). In contrast, ^99mTc tracers such as sestamibi are in widespread use, but the majority of studies defining the accuracy of conventional sestamibi SPECT for predicting functional recovery are single-centre studies, with 20 to 50 patients each [3‐9]. Many authors have stressed the importance of a quantitative approach. However, quantitation in many of the initial studies utilized in-house software developed by the individual centre, which might not be widely available. These factors tend to limit confidence in the use of ^99mTc SPECT imaging for viability assessment. …