Abstract 3137: Should Contrast be Given to All Patients Undergoing Stress Echocardiography? An Angiographic Study of Incremental Benefit and Cost-Effectiveness
Background: LV opacification (LVO) improves image quality (IQ) and diagnostic certainty of stress echo (SE) in pts with poor IQ. Many centers now use contrast in all SE, irrespective of IQ. We examined whether routine use of LVO added incremental benefit and was cost effective for diagnosis of CAD.
Methods: Pharmacologic and/or exercise SE was performed with LVO in 135 pts (81men, 56 ± 10 years) undergoing quantitative angiography for investigation of chest pain. Standard resting and stress images were followed by LVO. Segmental wall motion scoring was performed in the usual fashion. A cost effectiveness model and sensitivity analysis was based on published event rates of 20% over 3 years in pts with a positive stress echo on medical therapy.
Results: Significant CAD (>50% stenosis) was present in 75 pts (42 with single vessel disease). LVO increased the sensitivity for CAD (80 to 91%, p=0.03), including single vessel CAD (65 to 87%; p=0.04), with no change in specificity (72 to 77%, p=NS). Benefit from contrast (seen in 14% pts) was unrelated to resting IQ. Contrast administration in all pts added 59% to SE cost (p<0.001). In a model based cardiac outcome post SE, the cost per correct diagnosis was $1069 dollars (range $802 – $1,337). Effect of varying false positive/negative rates is shown in Figure⇓; cost reduction was only noted with improvement of the false positive rate.
Conclusions: SE with LVO adds significant incremental diagnostic benefit to standard imaging for the diagnosis of CAD, especially single vessel CAD. Despite improved diagnostic sensitivity, use of contrast did not result in cost neutrality when compared with unenhanced echocardiography.