Monday, November 5, 2007

Supine bicycle exercise echocardiography improves CAD detection

Supine bicycle exercise echocardiography improves CAD detection

5 November 2007

MedWire News: Supine bicycle exercise echocardiography (BEE) improves coronary artery disease (CAD) detection and evaluation of coronary stenosis severity, researchers report in the Journal of the American College of Cardiology.

"The possible assessment of the ischemic threshold in addition to the site, extent, and severity of induced ischemia might be a useful tool for stratifying the need for coronary revascularization in symptomatic patients," Luc Piérard (University Hospital Sart Tilman, Liège, Belgium) writes in an accompanying editorial.

William Zoghbi (The Methodist DeBakey Heart Center, Houston, Texas, USA) and colleagues assessed whether imaging during the intermediate stages of exercise using supine BEE improves the diagnosis of CAD, compared with just rest and peak exercise echocardiography, in 104 patients suspected of CAD.

Echocardiography was performed while the patient pedalled at a constant speed in a BEE bed with a maximum head elevation of 20°, beginning at a workload of 25 W and increasing by 25 W every 3-minute stage. Images were digitized at rest, 25 W, 50 W, and peak exercise.

Overall, 30 patients had one-vessel disease, 24 had two-vessels affected, seven had three-vessel CAD, and 43 had no significant coronary artery lesions.

Imaging during intermediate stages of exercise significantly improved the sensitivity for detection of all individual vessel stenosis (78% vs 58%, p<0.001) and the patient's overall CAD (94% vs 74%, p<0.001) compared with peak exercise imaging.

Intermediate stages and peak exercise imaging had similar specificities for the detection of affected vessels (83% and 81%, respectively) and patients (64% and 60%).

Furthermore, patients with ischemia had a significantly increased ventricular end-systolic volume (LVESV) from the intermediate stage to peak exercise, compared with the change from rest to peak exercise (33.5% vs 17.5%, p<0.001).

A change in LVESV from intermediate stage to peak exercise of more than 10% predicted CAD with a sensitivity of 94% and a specificity of 74%. The researchers therefore suggest that "the change in LVESV during exercise is a useful parameter for the detection of CAD."

Zoghbi et al conclude: "During BEE, the acquisition and interpretation of images during the intermediate stages of exercise, in addition to those at peak exercise, improve the detection of CAD and allow a physiologic assessment of the severity of coronary stenosis."

J Am Coll Cardiol 2007; 50: 1857-1863

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