Dobutamine Echocardiography In Patients With Ischemic Heart Failure Evaluated for Revascularization

BACKGROUND:

The number of individuals presenting with coronary artery disease (CAD) with impaired left ventricular (LV) function (measured as ejection fraction {EF}<35%), and clinical evidence of heart failure (HF) continues to increase. Patients with these conditions face the need for continuous and intensive medical management and poor quality of life. The STICH trial is designed to compare medical management to surgical revascularization in these patients. STICH's design includes myocardial function determination by several methods. The timely and important question of myocardial viability when function is poor is being examined using radionuclide methods. However, there is no consensus on the best technique to determine myocardial viability, or data to support this assessment as a potential determinant of prognosis following surgery. DECIPHER STICH adds dobutamine echocardiography (DE) for myocardial viability measurement to the parent trial. The study is of significance by addressing an important question and adding data for a technique that bears approximately half the cost of radionuclide methods. Furthermore, the revised design will allow for randomized and blinded evaluations of different treatment modalities according to myocardial viability determined by two different techniques.

DESIGN NARRATIVE:

The Dobutamine Echocardiography in Patients with Ischemic Heart failure Evaluated for Revascularization Study, as part of the Surgical Treatment for Ischemic Heart Failure Trial (DECIPHER-STICH), is designed to address the hypothesis that assessment of myocardial viability with dobutamine echocardiography (DE) in patients with coronary artery disease (CAD), left ventricular (LV) dysfunction and heart failure (HF) identifies the patients who derive the greatest survival benefit from surgical revascularization over medical therapy. In addition, this study will determine the value of DE for the prediction of recovery of LV function following revascularization, the clinical value of DE relative to that of radionuclide techniques used for the same purpose, and the relationship between abnormal LV size and shape and the contractile reserve of dysfunctional myocardium.

DECIPHER-STICH is an ancillary study to the large-scale STICH trial, a multicenter international randomized study designed to define the role of coronary artery bypass grafting (CABG) and surgical ventricular restoration (SVR) in the treatment of HF in patients with CAD and LV dysfunction. In previous studies, DE has compared favorably to other methods for the detection of viable myocardium. The widespread availability of echocardiography and the possibility of simultaneously deriving information about structural abnormalities (e.g., thrombi), valve function, and intracardiac pressures in addition to the real-time assessment of regional and global systolic function make DE particularly useful for the comprehensive evaluation of CAD patients with LV dysfunction. Because patients in the STICH trial will also undergo radionuclide tests, the DECIPHER-STICH study will allow a comparison of the most commonly used techniques for assessment of myocardial viability. Patients recruited into the STICH trial will be invited to participate in the DECIPHER-STICH study and asked to sign a separate consent form prior to the randomized assignment of therapy. Forty centers from North America and Europe recruiting patients into the STICH trial have agreed to take part in the DECIPHER-STICH study. A total of 1,450 of the 2,800 patients enrolled into the STICH trial will undergo DE prior to treatment. DECIPHER-STICH will address the hypothesis of greater beneficial effect of coronary artery bypass surgery (CABG) over medical therapy alone on 3-year survival rate with 80% power to detect a 25%-to-12.5% reduction in all-cause mortality in patients with viable myocardium. In addition, the study will have >99% power to address three important secondary hypotheses. The results of this study will provide definitive information regarding the value of assessing myocardial viability with DE and significant clinical implications for the selection of patients with CAD, LV dysfunction, and HF who are most likely to benefit from surgical revascularization.