Efficacy of pre-operative levo-phase pulmonary angiograms in detecting left atrial thrombi

We have studied the efficacy of levo-phase pulmonary angiograms in detecting thrombosis of the left atrium or its appendage in 33 patients with rheumatic mitral stenosis who subsequently underwent open-heart surgery. Left atrial thrombi had been suspected in all these patients due to the presence of atrial fibrillation and/or history of systemic embolization. The angiographic criteria for the presence of thrombus included mobile or persistent fixed filling defects of constant size in the contrast shadow of the left atrium or its appendage, partial or complete non-visualization of the left atrial appendage, irregular outline of the left atrium or its appendage and an atrial chamber which appeared smaller than the atrial shadow. 19 patients showed one or more angiographic features of thrombosis. All the patients subsequently underwent open-heart surgery for mitral valve disease, and thrombi were found in 17 patients. The angiogram was false positive in three patients, and false negative in one patient. The angiographic diagnosis of left atrial thrombosis by levo-phase pulmonary angiography has a sensitivity of 94%, specificity of 81.3%, and predictive value of 84.2%. Non-visualization of left atrial appendage as the only feature of thrombus formation was seen in five patients, and thrombi were subsequently formed at surgery in four patients (80%). Levo-phase pulmonary angiograms are safe and reasonably accurate for preoperatively detection of left atrial thrombi, and should be performed in all the patients of mitral stenosis if left atrial thrombi are clinically suspected.