BACKGROUND
During the past few years, transesophageal echocardiography (TEE) has been increasingly used in clinical cardiology; data concerning the practicability and safety of the technique, however, are rare.
METHODS AND RESULTS
This report analyzes the experience of 15 European centers performing TEE studies for at least 1 year. At the time of this survey, 10,419 TEE examinations had been attempted or performed in these institutions. These TEE examinations were carried out by 54 physicians, 53.7% of whom had been trained in endoscopic techniques. Within the same time period, 160,431 precordial echocardiographic examinations were performed in the 15 institutions; the ratio between TEE and transthoracic studies averaged 9.03 +/- 6.4% (range of the 15 centers, 1.4-23.6%). Of the 10,419 patients, 9,240 (88.7%) were conscious inpatients or outpatients at the time of the TEE examination; the vast majority of the conscious patients did not receive intravenous sedation before TEE. In 201 cases (1.9%), insertion of the TEE probe was unsuccessfully attempted because of a lack of patient cooperation and/or operator experience (98.5%) or because of anatomical reasons (1.5%). In 90 of 10,218 TEE studies (0.88%) with successful probe insertion, the examination had to be interrupted because of the patient's intolerance of the echoscope (65 cases); because of pulmonary (eight cases), cardiac (eight cases), or bleeding complications (two cases); or for other reasons (seven cases). One of the bleeding complications resulted from a malignant lung tumor with esophageal infiltration and was fatal (mortality rate, 0.0098%).
CONCLUSIONS
This multicenter survey documents that TEE studies are associated with an acceptable low risk when used by experienced operators under proper safety conditions.
Background-Chemokines expressed on atherosclerotic endothelium or deposited by activated platelets have been implicated in monocyte recruitment during atherogenesis and restenosis. Although the involvement of P-selectin in these processes is evident from studies in knockout mice, it has not been elucidated whether delivery of platelet chemokines requires P-selectin, thus serving as a P-selectin-dependent effector function. Methods and Results-Using immunofluorescence and laminar flow assays, we found that the deposition of the platelet-derived chemokine RANTES and monocyte arrest subsequently triggered by RANTES immobilized on inflamed endothelium are more efficient after preperfusion than after static preincubation of platelets and appear to depend on interactions of platelet but not endothelial P-selectin. This was revealed by the effects of P-selectin antibodies and comparison of P-selectin-deficient and wild-type platelets. Immunohistochemistry detected a substantial luminal expression of RANTES on neointimal lesions in wire-injured carotid arteries of apolipoprotein E (apoE)-deficient mice but not of mice with a combined deficiency in apoE and P-selectin (or platelet P-selectin). As assessed by histomorphometry, treatment of apoE-deficient mice with the RANTES receptor antagonist Met-RANTES markedly reduced neointimal plaque area and macrophage infiltration. Conclusions-Our data suggest that RANTES deposition and subsequent monocyte arrest are promoted by platelet P-selectin and involved in wire-induced intimal hyperplasia, and that blocking RANTES receptors attenuates neointima formation and macrophage infiltration. This mechanism represents an important component explaining the protection against neointimal growth in P-selectin-deficient mice and may represent a novel approach to the treatment of restenosis or atherosclerosis by the administration of chemokine receptor antagonists.
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