Supine bicycle versus post–treadmill exercise echocardiography in the detection of myocardial ischemia: a randomized single-blind crossover trial

Abstract

OBJECTIVESWe sought to determine the comparative accuracy of supine bicycle exercise echocardiography (SBE) and posttreadmill exercise echocardiography (TME) in detecting myocardial ischemia in patients with known or suspected coronary artery disease (CAD).BACKGROUNDSupine bicycle echocardiography and TME have been used for evaluation of CAD. However, the comparative accuracy of these modalities in the detection of ischemia in the same patients is not known.METHODSSeventy-four patients (age 59 ± 9 years [mean ± SD]) referred for evaluation of coronary disease underwent SBE (starting at 25 to 50 W with 25-W increment every 3 min) and post-TME (Bruce protocol) in a random sequence. Digitized images at baseline and maximal exercise were interpreted in a random and blinded fashion.RESULTSMaximal heart rate was higher during TME, whereas systolic blood pressure was higher during SBE, resulting in a similar double product. At quantitative angiography (n = 67), 57 patients had coronary stenosis (>50%). During SBE, ischemia was detected in 47 patients compared with 38 patients by TME (p < 0.001). Wall motion score index at maximal exercise was higher with SBE than with TME (1.48 ± 0.51 vs. 1.38 ± 0.43; p < 0.001). The extent of myocardial ischemia (number of ischemic segments) was higher during SBE compared with TME (3.3 ± 3.4 vs. 2.3 ± 2.9 segments; p = 0.004), whereas severity of abnormal wall motion was similar. The sensitivity of SBE and TME for CAD was 82% and 75% with a specificity of 80% and 90%, respectively. Image quality was similar with both techniques. Patients and sonographers favored SBE over TME.CONCLUSIONSDuring SBE and TME exercise, patients achieve a similar double product. During SBE, however, the detection of ischemia is more frequent and more extensive which, along with patient and sonographer preference, makes supine bicycle exercise a valuable stress echocardiographic modality.