Abstract 3782: The Clinical Significance and Pathological Findings of the Deep Echo Attenuation in Intravascular Ultrasound
Background: The presence of deep echo attenuation (DEA) without dense calcification is sometimes detected by intravascular ultrasound (IVUS) in atherosclerotic coronary lesions, which may influence on coronary flow after percutaneous coronary intervention (PCI). However, the clinical significance of DEA has not yet been clarified.
Methods: Three hundred-seventy nine lesions in 341 patients, who underwent preintervention IVUS, were investigated. Plaque morphologies in IVUS were analyzed, and the impact of DEA and other characteristics on coronary flow after PCI were assessed by TIMI flow grade using univariate and multivariate analysis. Further, directional coronary atherectomy was performed in another set of 60 lesions to assess pathological findings of the atheroma with or without DEA (DEA+ 30 lesions, DEA-30 lesions).
Results: DEA was observed in 138 (36.4%) lesions. In the present study, 154 lesions in patients with acute coronary syndrome (ACS) and 225 lesions in non-ACS were assessed. The frequency of DEA was significantly higher in ACS than non-ACS (48.1% (74/154) vs. 28.4% (64/225), p< 0.001). In the lesions with DEA, positive remodeling was observed more frequently than without DEA (45.9% for ACS vs. 20.0% for non-ACS, p<0.001). Slow/no flow after PCI (TIMI grade: 0–2) was observed in 28 lesions (7.4%). In the univariate analysis, significant predictors for slow/no flow after PCI were ACS (OR 7.7, 95% CI 2.9–20.8), the presence of thrombus (OR 6.1, 95% CI 2.8–13.5), large plaque (OR 3.3, 95% CI 1.4–7.9) and DEA (OR 6.0, 95%CI 2.5–14.5). In the multivariate analysis, the presence of DEA remained significant (P<0.05). In the pathological assessment, the frequency of microcalcium deposits (60.0% vs. 23.3%), rich cholesterol crystals (60.0% vs. 16.7%), and macrophage infiltrations (46.7% vs. 16.7%) were significantly higher in lesions with DEA than without DEA (respectively, p<0.05).
Conclusion: The presence of DEA was significant predictor for slow/no flow after PCI. The atherosclerotic plaque composition including lipid rich plaque with microcalcium deposits may be related with the image of DEA in IVUS examination, and these lesions might favor distal microvascular embolization during PCI, resulting slow/no flow phenomenon.