We read with interest Peteiro et al. ‘s finding that peak treadmill exercise echocardiography is superior to peak supine bicycle exercise echocardiography and post–treadmill exercise echocardiography for the detection of inducible coronary artery ischemia.
Although the investigators state that the patients accepted into the study had to be able to exercise on both a treadmill and a bicycle, we feel that a degree of caution is needed before applying the results more generally.
The accuracy of exercise echocardiographic studies is highly dependent on image quality, regardless of the stressor used to elevate heart rate. Clearly, peak exercise treadmill echocardiography is technically more challenging than the other two techniques because images must be obtained while the patient is walking on the treadmill. Impressively, the investigators were able to obtain very similar visualization of wall segments using all three techniques. However, we note that only 15% of the subjects studied were women, and there was no record of body mass index or other measures of body habitus in the article.
As the investigators are well aware, both female and obese patients make up a significant proportion of those referred for stress echocardiography. These groups can be the most challenging in which to obtain diagnostic studies, because acoustic windows may be limited by excessive fat or breast tissue. The unintentional exclusion of patients such as these may have a significant effect on the accuracy of image interpretation and therefore the overall outcome of the study.
It would therefore be useful to know the body mass indexes of the study population, why such a low percentage of patients were women, and how the investigators believe that these factors might have affected the outcome of their study.