Given the above, it should come as little surprise that contrast use has been shown to improve the diagnostic accuracy of stress echocardiography, during both exercise [10] and pharmacological [11-12] stress. Although contrast use itself has some associated cost, an accurate test result can prevent further unnecessary investigations [13] and the cost savings of using contrast stress echocardiography for risk stratification (including early discharge) in patients admitted to hospital with chest pain has been demonstrated [14]. Inter-observer variability of image interpretation is also reduced by contrast administration. A retrospective analysis of over 18000 patients who received contrast during stress echocardiography found that the diagnostic accuracy in those with sub-optimal image quality receiving contrast was equivalent to those with optimal image quality, demonstrating the efficacy and safety of using contrast during stress imaging [15].
Consequently, the EAE guidelines for contrast echocardiography [16] recommend contrast use when two or more endocardial borders of contiguous segments are not well visualized in order to:
- Obtain diagnostic assessment of systolic wall thickening at rest and at stress
- Increase the proportion of diagnostic studies
- Increase reader confidence in image interpretation