Resolution of left atrial thrombi with anticoagulant therapy in candidates for percutaneous transvenous mitral commissurotomy.

BACKGROUND AND AIMS OF THE STUDY: Little is known of the fate of left atrial thrombus (LAT) among candidates for percutaneous transvenous mitral commissurotomy (PTMC) after oral anticoagulation (OA) therapy. The aim of this study was to estimate the resolution rate of documented LAT, and to determine its significant predictors among this population. METHODS: In this prospective cohort study all consecutive candidates for PTMC with documented LAT were followed between August 1996 and December 1999. All patients underwent both transthoracic (TTE) and transesophageal echocardiography (TEE) and received OA therapy (INR 2.0-3.0). The fate of LAT was studied serially using both TTE and TEE. RESULTS: A total of 75 patients was followed for six to 34 months (mean 12.2+/-6.2 months; total 914 patient-months). The LAT was completely resolved in 48 patients (5.25 per 100 pt-months; 95% CI 3.96-6.97). The overall resolution rate was 63.0 per 100 patients per year (95% CI 47.5-83.6). Patients with resolved LAT underwent uneventful PTMC. The median duration of LAT resolution was 16 months (95% CI 12.7-19.3). Significant predictors of LAT resolution were the size of the LAT (RR = 0.8 for each 1 cm2 increase in LAT; 95% CI 0.6-0.9; p = 0.012) and severity of the left atrial spontaneous echo contrast (LASEC) detected by TEE (RR = 0.6 for each 1 level increase of the LASEC severity score; 95% CI 0.4-0.9; p = 0.032). CONCLUSION: The smaller the LAT and the less severe the LASEC, the greater the likelihood of LAT resolution after OA therapy and the enhanced possibility of safely performing PTMC.

A prognostic model for predicting the disappearance of left atrial thrombi among candidates for percutaneous transvenous mitral commissurotomy.

OBJECTIVES: We sought to develop a prognostic model to predict the disappearance of left atrial thrombi (LAT) among candidates for percutaneous transvenous mitral commissurotomy (PTMC). BACKGROUND: Complete LAT resolution can be achieved with oral anticoagulation, allowing a number of patients to safely undergo PTMC. METHODS: We randomly allocated 108 PTMC candidates with LAT into two subsets---one to derive the model and the other to validate it. The existence of LAT and its size were measured by transesophageal echocardiography. Patients were given oral anticoagulation and followed up for 6 to 34 months. There was a 62% disappearance rate of LAT. RESULTS: We developed the following model: P = 1/(1 + exponential [-8.1 + 1.8 NYHA + 0.7 area]), where NYHA = New York Heart Association functional class (from I to IV), and area = LAT area (in cm(2)). The model was well calibrated (goodness-of-fit test, p = 0.82) and well discriminated (area under the receiver-operating characteristics [ROC] curve = 0.92). Performance in the validating sample was equally good (area under the ROC curve = 0.94; goodness-of-fit test, p = 0.16). When a cut-off point of p > 0.7 was used to designate the LAT disappearance in the validating set, the model had a sensitivity, specificity and positive and negative predictive values of 93.3%, 79.2%, 84.9% and 90.5%, respectively. CONCLUSIONS: Combined clinical (NYHA functional class) and echocardiographic (LAT area) variables are predictive of the 34-month outcome of oral anticoagulation for LAT resolution among PTMC candidates. This simple and highly predictive model might be potentially useful for clinical assessment and proper management.