Clinical Investigation
Coronary Artery Disease
Assessment of Temporal Heterogeneity and Regional Motion to Identify Wall Motion Abnormalities Using Treadmill Exercise Stress Three-Dimensional Echocardiography

https://doi.org/10.1016/j.echo.2008.11.030Get rights and content

Background

Exercise 3-dimensional echocardiography (3DE) may avoid the problem of poorly matched pre- and post-exercise 2-dimensional echocardiograms (2DE), and contraction front mapping (CFM) may be used to quantify the temporal homogeneity of contraction. We compared 3DE with 2DE for identification of angiographically significant disease.

Methods

Conventional 2DE and 3DE at rest and peak stress were performed in 110 patients (78 men, aged 60 ± 11 years) who underwent angiography within 6 months. Offline assessment of CFM was performed qualitatively (delayed regional relaxation in a coronary territory) and quantitatively (difference in regional and global contraction delays from rest to peak in individual segments). The accuracy of each test was calculated for identification of 70% or more diameter angiographic stenoses.

Results

Patients were excluded for nondiagnostic stress (n = 12) or poor-quality 3DE (n = 8). Time until end of 2DE acquisition was 58 ± 25 seconds, and time until end of 3DE (taken after 2DE) was 109 ± 55 seconds. Receiver operating characteristic analyses were used to define normal cutoff ranges of contraction delays for the following coronary territories: left anterior descending (≤10%), left coronary artery (≤10%), right coronary artery (≤11%), and overall (≤10%). The concordance between angiography and qualitative CFM (63%) was similar to quantitative CFM (70%). The sensitivity of wall motion assessment at 3DE (40%) was lower than CFM (55%, P = .04) and 2DE (83%, P < .01) at comparable levels of specificity (65%, 84%, and 78%).

Conclusion

Although the higher specificity of 3DE may represent avoidance of false-positives from off-axis imaging, the sensitivity of 3DE is insufficient for clinical use. Analysis of the temporal distribution of contraction may be more sensitive than 3D wall motion assessment for identification of ischemia at exercise 3DE.

Section snippets

Study Design

We prospectively recruited 110 patients (78 men, aged 60 ± 11 years) who were referred for clinical treadmill exercise echocardiography (using the standard Bruce protocol) and had a coronary angiography within 6 months. All patients had conventional 2DEand 3DE at rest and peak stress, and CFM of 3DE images (Tomtec, Unterschlessheim, Germany) was performed offline. Contrast agents were not used in this study.

Coronary Angiography

Selective coronary angiography was performed in a standard fashion. Quantitative

Patient Characteristics

The results were analyzed in 90 patients (63 men, aged 60 ± 10 years); patients with poor 3DE image quality (n = 8) and submaximal stress (<80% of their maximal heart rate with exercise; n = 12) were excluded. Table 1 summarizes the clinical characteristics, presence, and cause of CAD and resting and peak wall motion scores. Time from cessation of exercise until the end of 2DE acquisition was 58 ± 25 seconds, and time from cessation of exercise until the end of 3DE (taken immediately after 2DE)

Discussion

In this assessment of new exercise echocardiography technologies, angiographic correlation remained best with 2DE followed by CFM and 3DE. The greater specificity of 3DE than 2DE, which may be due to the avoidance of off-axis imaging, was at the cost of an unacceptably low sensitivity of noncontrast stress 3DE.

Limitations

This study has several limitations. First, 3DE was acquired after 2DE at peak exercise in this study, which may have allowed time for wall motion abnormalities to resolve, contributing to the lower sensitivity than 2DE. Because the early post-exercise period is the most valuable diagnostically, there is reluctance to use this time for acquisition of lower-resolution 3DE images. The only means of avoiding compromising clinical data would be to re-stress the patients, which we considered

Conclusions

The current image quality of 3DE does not seem to be sufficient to add incremental value to exercise noncontrast 2DE, although the specificity of 3DE exceeds that of noncontrast 2DE, probably by ensuring that pre- and post-exercise images are matched. Although there are theoretic attractions to analyzing the temporal distribution of contraction, and 3D is an attractive means of summarizing this for the entire LV, 3D wall motion assessment is currently insufficiently accurate for the

References (31)

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