A middle-aged patient on hemodialysis for over a decade, dialyzing through a right upper extremity arteriovenous (AV) fistula, was sent from the dialysis unit because the access wasn’t working. The staff noted that they were able to express clots from the fistula. The patient had a history of central venous stenosis and had previously undergone right subclavian stenting. Given their lab results, immediate dialysis was necessary, but vascular intervention couldn’t be performed right away. So, we needed a temporary hemodialysis catheter and turned to POCUS to assess the internal jugular (IJ) veins before placement.

The left IJ was patent, but the right IJ revealed a near-occlusive thrombus as shown below. Based on its mostly hypoechoic appearance with hyperechoic borders and septations, it was likely subacute. We initiated anticoagulation therapy and placed a left IJ catheter while awaiting further intervention for the fistula.

This case highlights a key point: the high blood flow rates in central veins—common in hemodialysis patients with AV access—can contribute to endothelial injury and stenosis. Conversely, central vein stenosis, often due to repeated or long-term catheterization, can lead to stasis and increase the risk of thrombosis, ultimately compromising an AV access.

Before placing a catheter, a quick POCUS scan of the central veins can help identify thrombosis, guide safe placement, and prevent complications. Below are more examples of thrombosis detected before catheter placement.

Below are images of a IJV thrombus with a ball-like hyperechoic clot. The echotexture and shape suggest a chronic thrombus and the lumen is patent.

Below is a case of axillary vein thrombosis (snake clot) secondary to a PICC line (Peripherally Inserted Central Catheter).

Below is a clot sitting right on the guidewire in the IJ vein, caught while I was placing a dialysis catheter. Interestingly, the vessel looked clear on initial ultrasound. The clot likely formed from endothelial injury during needle insertion and then got carried into the vein as the wire advanced. This seems especially plausible in a patient with a deranged coagulation profile. We went ahead and placed the catheter over the wire since pulling it back/aborting the procedure also risked dislodging the clot. Fortunately, the procedure went smoothly with no adverse events.