A prognostic model for predicting the disappearance of left atrial thrombi among candidates for percutaneous transvenous mitral commissurotomy.
OBJECTIVE
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.
Silaruks
Songkwan
S
Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. songkw-s@medlib2.kku.ac.th
Thinkhamrop
Bandit
B
Tantikosum
Wirote
W
Wongvipaporn
Chaiyasith
C
Tatsanavivat
Pyatat
P
Klungboonkrong
Virat
V
D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use*; D002404:Catheterization; D015331:Cohort Studies; D000075202:Contraindications; D017548:Echocardiography, Transesophageal; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging* / Q000628:therapy*; D015233:Models, Statistical; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D013997:Time Factors; D016896:Treatment Outcome
D000925:Anticoagulants