Purpose or Case Report: Neonates with prolonged hospitalization often require PICCs. The concern for PICC-related complications, including venous thrombosis, infection, catheter migration and breakage, often prompts Doppler ultrasound (US) evaluation. However, peri-catheter thrombus in a neonate can be challenging to evaluate, as the accessed peripheral veins in neonates are small, some less than 1mm in luminal diameter. Small-bore catheters may occupy the entirety of the vessel lumen, which can produce absence of peri-catheter flow, which is confounding for thrombus. This distinction has implications for hematologic management.
Methods & Materials: IRB-approved A retrospective review of 644 extremity US studies for a PICC-related indication in 374 NICU infants and neonates (Sept 2009-Sept 2019). Reports were evaluated for descriptions of peri-catheter flow and frequency in venous thrombosis by categorizing findings into negative, occlusive or non-occlusive thrombosis, and indeterminate (reported as no definite thrombus, thrombus not excluded, or were purely descriptive). Catheter occupation of a vessel was identified by qualitative description of absent peri-catheter flow with catheter filling or occupying the vessel lumen. Chart review for patient demographics, underlying diagnosis, and initiation of anticoagulation was performed.
Results: The patient median age was 1.3 months (IQR 0.6-3.2 months), 44% female. An US diagnosis of thrombosis was reported in 52% (341/644) of studies performed for 109 patients (29% of total patients receiving an US). Catheter occupation was described in 16% (102/644) of studies for 83 patients, where 21% were reported negative for thrombus, 33% positive for thrombosis, and 46% indeterminate. Among studies reporting the catheter filling the vein, most with an indeterminate US did not receive anticoagulation (80%, 36/45). Alternatively, catheter occupation studies with a positive US finding for thrombosis were anticoagulated (74%, 20/27).
Conclusions: Absent pericatheter flow related to the catheter filling the vessel lumen is interpreted variably for thrombosis. Those reported positive for thrombosis often received anticoagulation, while those reported indeterminate were often not anticoagulated. Consensus on complete catheter occupation of a vessel lumen as it relates to thrombosis is important as it has implications on hematologic management of neonates. Further investigation of the normal progression of occlusive catheters is warranted in this population.