RESUMEN
INTRODUCTION AND OBJECTIVES: Echocardiography is considered a basic tool in the diagnosis and management of infective endocarditis. Transesophageal echocardiography is more sensitive than transthoracic echocardiography. Our aim was to describe which factors are related to the ability of transthoracic echocardiography to establish the diagnosis of infective endocarditis. The presence of this factors in a patient with a normal transthoracic echocardiography would make unnecessary to perform a transesophageal echocardiography and would suggest to seek for other diagnostic possibilities. METHODS: 127 consecutive patients admitted to our hospital with the diagnosis of infective endocarditis and a complete transthoracic echocardiography and transesophageal echocardiography comprised our study group. Predisposing factors and clinical, echocardiographic and microbiological variables were studied. RESULTS: The presence of a cardiac murmur, the presence of an optimal acoustic window, degenerative valvular disease as the predisposing factor for infective endocarditis and positive blood cultures were related to the ability of transthoracic echocardiography to diagnose the existence of signs of infective endocarditis on its own. Nevertheless, only the presence of a cardiac murmur (RR 2.724; 95% CI 1.071-6.926; p 0,035) and the presence of an optimal acoustic window (RR 5.538; 95% IC 2.75-11.15; p < 0.001) were found as independent factors to detect those patients in which transthoracic echocardiography is able to diagnose signs of infective endocarditis on its own. CONCLUSIONS: The diagnostic accuracy of transthoracic echocardiography to detect echocardiographic signs of infective endocarditis is high in those patients with cardiac murmur and optimal acoustic window. In those patients with these characteristics, without prosthetic heart valves and a negative transthoracic echocardiography for infective endocarditis other diagnostic possibilities should be ruled out before performing of a transesophageal echocardiography.