ECHOGRAPHIC DETECTION OF LATENT SEVERE THROMBOTIC STENOSIS OF THE SUPERIOR VENA-CAVA AND INNOMINATE VEIN IN PATIENTS WITH A PACEMAKER - INTEGRATED DIAGNOSIS USING SONOGRAPHY, PULSE DOPPLER, AND COLOR-FLOW

Thrombosis of the innominate vein and SVC is a serious complication in patients with pacemakers, inducing pulmonary embolism or SVC syndrome . Venography is the definitive method for its diagnosis; however, it i s too invasive for related studies. The purpose of this study was to v alidate sonography, pulse Doppler, and color flow in detecting noninva sively innominate vein or SVC thrombosis in patients with pacemakers. In 53 patients with pacemakers, the 1 severe SVC stenosis and 18 sever e innominatevein stenoses due to thrombosis were diagnosed by digital subtraction angiography. Sonography accurately showed the severe SVC s tenosis due to thrombosis, but had limitations on the innominate vein thrombosis. Color flow demonstrated mosaic flow, indicating poststenot ic turbulence due to stenosis of the innominate vein and SVC caused by thrombosis in 15 of 16 patients, and pulse Doppler disclosed absence of flow due to complete occlusion of the innominate vein in 2 of 2 pat ients. Sensitivity and specificity for detecting severe innominate vei n stenosis due to thrombosis using combined color flow and pulse Doppl er was 94% and 100%, respectively. In conclusion, sonography, pulse Do ppler, and color flow allow accurate detection of severe innominate ve in or SVC stenosis due to thrombosis, and are therefore useful for the follow-up of patients with a pacemaker.