Objective—To assess the relative merits of transthoracic and transoesophageal echocardiography before balloon dilatation of the mitral valve.
Design—Transthoracic and transoesophageal echocardiograms were prospectively performed in 35 patients being considered for balloon dilatation of the mitral valve. Echocardiograms were analysed for image quality, the assessment of valve morphology, the detection of left atrial thrombus, and the assessment of mitral regurgitation and other valvar pathology.
Patients—35 consecutive patients with symptomatic dominant mitral stenosis.
Interventions—30 eventually underwent balloon dilatation of the mitral valve by the Inoue technique. Five patients had mitral valve replacement.
Main outcome measures—Echocardiographic and surgical detection of left atrial thrombus and successful, uncomplicated balloon dilatation of the mitral valve.
Results—Left atrial thrombus was detected in 1/35 patients by transthoracic studies compared with 6/35 from transoesophageal studies. Otherwise both techniques gave comparable results. Thrombus was confirmed at mitral valve replacement in five patients. Successful dilatation of the mitral valve was performed in 30 patients.
Conclusions—Transthoracic echocardiography is a useful screening procedure but transoesophageal echocardiography is mandatory before balloon dilatation of the mitral valve for the detection of left atrial thrombus.