Gaining Respect for Echocardiographic Volumetric Quantitation: Observations on a Study of the Baseline Echocardiography Data from the STICH Echocardiography Core Laboratory

It is no exaggeration that echocardiography, because of the comprehensive information it generates and its noninvasive, real-time format, is indispensible in modern medicine. These features have made it the mostfrequentlyperformed cardiacimagingtest,whoseimages,bythe physical principles underlying their construction, are accurate representations of cardiac anatomy and absolutely quantifiable. However, the freehand nature of measurement techniques, the susceptibility of images to technical error and degradation, and the non-Euclidean shapes of cardiac structures (among other things) may lead to erroneous estimation of cardiac size. Volumetric algorithms incorporate larger samples of anatomy in computing cardiac size than singledimensional linear measurements and are thus superior to single dimensions. However, volumetric measurements have diffused only slowlyinto practice despite their historic contributions to the development of the cardiology canon through pioneering volumetric methods such as quantitative angiography. 1 A leading reason that echocardiographers avoid volumetric methods is the notion that they are ‘‘too time consuming.’’ However, as large clinical trials have proliferated, considerations of cost and patient safety and tolerance, in conjunction with deploying reference standard techniques such as magnetic resonance imaging, computed tomography, or scintigraphy, have resulted in a growing interest in relying on volumetric data from echocardiography. This shift has been facilitated by published guidelines 2,3 for both the content and conduct of clinical trials that emphatically endorse volumetric echocardiography. Recognizing this trend and seeking to improve the application echocardiography in clinical trials, the members of the Echocardiography Core Laboratory (ECL) of the Surgical Treatment for Ischemic Heart Failure (STICH) trial have analyzed their experience with baseline volumetric and Doppler data that were gathered at the onset of the trial and, on the basis of their impressions, present suggestions for improvement in clinical trials and clinical practice. 4 STICH is a large multicenter study of treatment strategies in advanced ischemic cardiomyopathy. Entry criteria include an ejection fraction (EF) < 35% and coronary obstruction amenable to bypass grafting. Between 2002 and 2006, 2,136 patients were enrolled and studied from 122 sites worldwide. The two hypotheses tested in this study were that surgery is associated with superior long-term survival compared with intensive medical therapy and that surgical resection of anterior dysfunctional myocardial segments combined with bypass has superior long-term survival to bypass alone. Echocardiographic data were collected as adjunctive to understanding the outcome end points. In their analysis of initial baseline data reported in this issue of JASE ,O het al. 4 aim to (1) define the feasibility of obtaining quality baseline data for the STICH cohort, (2) document baseline data from this cohort, and (3) generate recommendations for using echocardiography clinically.