Co-infection ratios versus inflammation, growth factors and progression of early atheromas.

Mycoplasma pneumoniae (MP) and Chlamydophila pneumoniae (CP) antigens are encountered in complicated atheromas and may be implicated in the diversity of atherosclerotic lesions. Mycoplasma can downregulate the immune system, altering levels of inflammation, which may favor the proliferation of other co-infectious agents. In the present study we analyze whether initially stable human atheromas exhibit different ratios of MP/CP antigens compared to ongoing atheromatous lesions. Two groups were examined for the presence of inflammatory cells, macrophages, growth factors and infectious agents: Group I (GI), n=16, early stable atheromas, <4 CD68(+) macrophages/400 x field, showing a normal distribution and a fibrous cap; Group II (GII), n=14, growing atheromas, > or =4 CD68+ cells/400 x field, lacking a fibrous cap, showing a non-normal macrophage distribution. The amounts of CP (but not MP) antigens and lymphocytes in GI were significantly lower than in GII. MP/CP ratios were higher in GI. MP correlated with CP and PDGFB in GI (r=0.79 and r=0.83, p<0.001), but not in GII (r=-0.4 and r=-0.08, p=0.81). MP and CP antigens are already present in early atheromas, and a higher MP/CP ratio correlates with increased growth factors, lower inflammation and plaque stability.

Diagnostic performance of stress perfusion and delayed-enhancement MR imaging in patients with coronary artery disease.

PURPOSE: To prospectively determine the accuracy of a combined magnetic resonance (MR) imaging approach (stress first-pass perfusion imaging followed by delayed-enhancement imaging) for depicting clinically significant coronary artery stenosis (> or = 70% stenosis) in patients suspected of having or known to have coronary artery disease (CAD), with coronary angiography serving as the reference standard. MATERIALS AND METHODS: The committee on human research approved the study protocol, and all participants gave written informed consent. This study was HIPAA compliant. Forty-seven patients (38 men and nine women; mean age, 63 years +/- 5.3 [standard deviation]) scheduled for coronary angiography were prospectively enrolled: 33 were suspected of having CAD (group A) and 14 had experienced a previous myocardial infarction and were suspected of having new lesions (group B). The MR imaging protocol included cine function, gadolinium-enhanced stress and rest first-pass perfusion MR imaging, and delayed-enhancement MR imaging. Myocardial ischemia was defined as a segment with perfusion deficit at stress first-pass perfusion MR imaging and no hyperenhancement at delayed-enhancement imaging. Myocardial infarction was defined as an area with hyperenhancement at delayed-enhancement imaging. RESULTS: One patient was excluded from analysis because of poor-quality MR images. Coronary angiography depicted significant stenosis in 30 of 46 patients (65%). In a per-vessel analysis (n = 138), stress first-pass perfusion MR imaging and delayed-enhancement imaging yielded sensitivity of 0.87, specificity of 0.89, and accuracy of 0.88, when compared with coronary angiography. The diagnostic accuracy of stress first-pass perfusion MR imaging and delayed-enhancement imaging was slightly better than that of stress and rest first-pass perfusion MR imaging in the entire population (0.88 vs 0.85), in group A (0.86 vs 0.82), and in group B (0.93 vs 0.90). CONCLUSION: Stress first-pass perfusion MR imaging followed by delayed-enhancement imaging is an accurate method to depict significant coronary stenosis in patients suspected of having or known to have CAD.