Duplex and color Doppler sonography of complications after percutaneous interventional vascular procedures.

Duplex and color Doppler sonography have proved to be excellent noninvasive modalities for evaluating complications of percutaneous interventional vascular procedures. Complications including hematoma, pseudoaneurysm, arteriovenous fistula, thrombosis, stenosis, and vessel occlusion are routinely diagnosed with Doppler sonography. Hematomas exhibit variable echogenicity and internal complexity but never demonstrate internal blood flow. A pseudoaneurysm is a contained extravasation of blood that, unlike a hematoma, maintains a patent vascular connection with the injured vessel. Puncture-related arteriovenous fistulas are false vascular channels between an adjacent artery and vein that demonstrate low-resistance arterial signal, high-velocity venous outflow, and variable flow patterns within themselves. Narrowing in a stent demonstrates high-velocity turbulent flow with conventional Doppler and color aliasing with color Doppler techniques. Thrombus can be seen directly as a mural-based or luminal defect; however, it is often alterations in color flow dynamics, waveform characteristics, and flow velocities that permit conclusive diagnosis. Early experience in evaluation of stent stenosis in patients with transjugular intrahepatic portosystemic shunts suggests that low-velocity shunt flow indicates stenosis, likely related to the presence of low-resistance collateral pathways. Familiarity with both the interventional procedures and their possible complications facilitates prompt diagnosis and treatment.