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Background—Balloon pulmonary angioplasty (BPA) is an alternative therapy for patients with chronic thromboembolic pulmonary hypertension who are ineligible for standard therapy, pulmonary endarterectomy. Although there are several classifications of vascular lesions, these classifications are based on the features of the specimen removed during pulmonary endarterectomy. Because organized thrombi are not removed during balloon pulmonary angioplasty, we attempted to establish a new classification of vascular lesions based on pulmonary angiographic images. We evaluated the success and complication rate of BPA in accordance with the location and morphology of thromboembolic lesions. Methods and Results—We reviewed 500 consecutive procedures (1936 lesions) of BPA in 97 patients with chronic thromboembolic pulmonary hypertension and investigated the outcomes of BPA based on the lesion distribution and the angiographic characteristics of the thromboembolic lesions, as follows: type A, ring-like stenosis lesion; type B, web lesion; type C, subtotal lesion; type D, total occlusion lesion, and type E, tortuous lesion. The success rate was higher, and the complication rate was lower in ring-like stenosis and web lesions. The total occlusion lesions had the lowest success rate. Tortuous lesions were associated with a high complication rate and should be treated only by operators with extensive experience with BPA. Conclusions—We modified the previous angiographic classification and established a new classification for each vascular lesion. We clarified that the outcome and complication rate of the BPA are highly dependent on the lesion characteristics. [ABSTRACT FROM AUTHOR]

Heme oxygenase-1 (HO-1) is a cytoprotective enzyme that is induced by intraplaque hemorrhage and degrades free heme and releases ferrous iron, which is rapidly sequestered by ferritin. In vitro studies have shown that binding of hemoglobin to hemoglobin scavenger receptor (CD163) induces HO-1 and the anti-inflammatory mediator interleukin (IL)-10. We immunohistochemically examined the relationship between CD163 expression in macrophages and intraplaque hemorrhage, HO-1, IL-10, and ferritin using coronary atherectomy specimens from patients with stable (SAP) or unstable angina pectoris (UAP). A total of 67 patients underwent atherectomy for SAP (n = 33) or UAP (n = 34). Samples were stained with antibodies against smooth muscle cells, macrophages, glycophorin- A (a protein specific to erythrocyte membranes), CD163, HO-1, IL-10, and ferritin. To identify cell types of HO-1-positive cells, double immunostaining was also performed. Double immunostaining for HO-1 and macrophages revealed that the vast majority of HO-1-positive cells were macrophages. Morphometric analysis demonstrated that CD163-positive macrophage score and the percentage of glycophorin-A-, HO-1-, IL-10-, and ferritin-positive areas were significantly higher in UAP than in SAP patients (CD163, P < .005; glycophorin-A, P < .0001; HO-1, P < .0001; IL-10, P < .005; ferritin, P = .0001). Moreover, CD163-positive macrophage score was positively associated with the percentage of glycophorin-A-, HO-1-, IL-10-, and ferritin-positive areas (glycophorin-A, r = 0.60, P < .0001; HO-1, r = 0.67, P < .0001; IL-10, r = 0.45, P < .0005; ferritin, r = 0.61, P < .0001). These findings suggest that enhanced expression of HO-1 and HO-1-related atheroprotective molecules plays an important role in exerting anti-inflammatory, antioxidant, and scavenging functions, which could contribute to plaque stabilization. [ABSTRACT FROM AUTHOR]