Background: Controversy exists concerning the need for aspiration before injection with hyaluronic acid (HA) fillers.
Objective: The authors undertook a study of HA products to determine if blood could be aspirated back into a syringe of HA when the needle has been primed or filled with HA.
Methods and materials: Two studies were set up to determine if or when blood could be withdrawn from a heparinized fresh tube of blood into the HA syringe. Two different techniques were tested; one using a slow-pull retraction of the plunger and up to a 5-second waiting time before release versus a rapid pullback and quick release.
Results: Review of these data demonstrates that the usual clinical method, which involves quick withdrawal and instant release of the syringe plunger does not allow for sufficient removal of the filler found intraluminal in the needle and may give rise to false negative results in vitro and likely in vivo with the exception being the Galderma/Medicis products.
Conclusion: In summary, withdrawal of the syringe plunger with no visible blood in the syringe does not eliminate the possibility of intravascular placement of the syringe needle.