Transesophageal echocardiography identified nonobstructive thrombi in 17.5% of patients with mechanical mitral valve prostheses that appeared normal on transthoracic echocardiography.
Observational (n=114)
Does transesophageal echocardiography improve the diagnosis of nonobstructive thrombosis in patients with mechanical mitral valve prostheses compared to transthoracic echocardiography?
Transesophageal echocardiography reliably identifies nonobstructive thrombi on mechanical mitral valve prostheses that are missed by transthoracic echocardiography, which can guide subsequent anticoagulation or surgical management.
Absolute Event Rate: 17.5% vs 0%
BACKGROUND: Diagnosis of a mechanical mitral valve prosthesis thrombosis is currently made with transthoracic Doppler echocardiography and occasionally with fluoroscopy. However, identifying a thrombus on a valve prosthesis may be difficult, especially if the thrombus is nonobstructive. To prospectively define the role of transesophageal echocardiography for identification of nonobstructive thrombi, we studied a series of patients in whom the prosthetic valve was considered to function normally on clinical examination and transthoracic echocardiography. METHODS AND RESULTS: One hundred fourteen consecutive patients with mechanical mitral valve prosthesis were investigated by both transthoracic echocardiography and transesophageal echocardiography. These examinations were performed for recent systemic emboli (15 patients), fever of unknown etiology (11 patients), routine postoperative evaluation (56 patients), and other reasons (32 patients). Based on transthoracic echo diagnosis, all prostheses were considered normal. Yet, in 20 patients transesophageal echocardiography revealed the presence of a 2- to 15-mm-long mobile thrombus localized on the atrial surface of the prosthesis. When compared with the remaining 94 patients with no visible thrombi, there was no significant difference between the two groups in terms of incidence of atrial fibrillation (65% versus 52%), left atrial size (48 +/- 9 versus 51 +/- 13 mm), left ventricular end-diastolic diameter (49 +/- 10 versus 51 +/- 13 mm) and fractional shortening (28 +/- 9% versus 31 +/- 10%), presence of spontaneous contrast to the left atrium (40% versus 41%), transprosthetic mean pressure gradient (4.0 +/- 1.4 versus 3.9 +/- 1.5 mm Hg), or the type of prosthesis used. After we discovered a nonobstructive thrombosis, patients were treated with heparin (n = 9) or oral anticoagulation (n = 11). The presence of a localized thrombus was confirmed in 3 patients who were operated on. In the present study, evolution appeared to depend on thrombus size: of 14 patients exhibiting a small ( or = 5 mm) thrombus developed complications or died. CONCLUSIONS: Transesophageal echocardiography appears to be a reliable method to diagnose thrombi on a mechanical mitral valve prosthesis, even when transthoracic Doppler echocardiographic parameters appear to be normal. Transesophageal echo assessment of thrombus size may be helpful in deciding whether a patient with mitral prosthesis should be treated by anticoagulation, thrombolysis, or valve rereplacement.
Guéret et al. (Sun,) conducted a observational in Mechanical mitral valve prosthesis (n=114). Transesophageal echocardiography vs. Transthoracic echocardiography was evaluated on Identification of nonobstructive thrombi. Transesophageal echocardiography identified nonobstructive thrombi in 17.5% of patients with mechanical mitral valve prostheses that appeared normal on transthoracic echocardiography.