The value of transesophageal echocardiography in predicting immediate and long-term outcome of balloon mitral valvuloplasty: comparison with transthoracic echocardiography.

Abstract

The purpose of this study was to assess the role of transesophageal echocardiography in predicting the immediate and long-term outcome of balloon mitral valvuloplasty, and compare the results to transthoracic echocardiography. Transesophageal echocardiography accurately detects left atrial thrombi and allows better visualization of mitral valve morphology; however, its value in predicting the immediate and long-term outcome of balloon mitral valvuloplasty had not been assessed as adequately as for transthoracic echocardiography. In 56 patients referred for balloon mitral valvuloplasty, both transesophageal and transthoracic echocardiography were performed (Group A). An echo score for both techniques was used to reflect mitral valve morphology, and its predictive value for immediate and long-term outcome of the valvuloplasty was assessed. The impact of transesophageal echocardiography in preventing procedural embolic events in those 56 patients was assessed by comparison to another group of 41 patients, who were examined only by transthoracic echocardiography prior to balloon mitral valvuloplasty (Group B). In Group A, transesophageal echocardiography detected left atrial thrombus in seven, while transthoracic echocardiography detected left atrial thrombus in two patients. After 2 months of warfarin therapy, a repeat transesophageal echo examination in four patients showed resolution of thrombus in three who went on to have balloon mitral valvuloplasty. Among the 52 patients who eventually had the procedure after thrombus was excluded by transesophageal echocardiography, there were no embolic events, compared to three embolic events among the 41 patients in Group B (P = 0.08). The transthoracic echocardiography scores, while slightly higher, correlated well with transesophageal echocardiography scores (r = 0.51, P < 0.001). The increase in mitral valve area did not correlate well to total transthoracic or transesophageal echocardiography scores, while it correlated negatively to valve calcification by transthoracic (r = -0.29, P < 0.05) and mobility by transesophageal echocardiography (r = -0.59, P < 0.02). At follow-up (7 +/- 4 months) nonsurvivors (7/56) had higher total scores by either transthoracic (P < 0.01) or transesophageal echocardiography (P < 0.05) compared to survivors. The percent reduction in mitral valve area was greater with age (r = 0.5, P < 0.02), time to follow-up (r = 0.67, P < 0.002), valve mobility by transthoracic echocardiography (r = 0.59, P < 0.01), and valve calcification by transthoracic echocardiography (r = 0.37, P = 0.09) and transesophageal echocardiography (r = 0.4, P = 0.07). Transesophageal echocardiography is superior to transthoracic echocardiography in detecting left atrial thrombi, and it may reduce the risk of embolic events following balloon mitral valvuloplasty. Assessment of mitral valve morphology by transesophageal echocardiography is complementary and not superior to assessment by transthoracic echocardiography. Mitral valve calcification and mobility appear to be the best morphological predictors of immediate and long-term outcome following balloon mitral valvuloplasty.