Vascular occlusion happens when filler is injected into an artery, or placed in enough volume beside one to compress it. Blood supply to the tissue beyond that point is cut off. Left untreated, the skin becomes ischaemic and can progress to necrosis within hours. Where filler enters an artery in the central face, it can travel backwards into the vessels supplying the eye and cause irreversible blindness. Strokes have been reported. These outcomes are uncommon. They are also catastrophic and time-critical, and the response is not technique. It is a protocol.
Management of high-dose hyaluronidase into and around the affected area, alongside supportive measures, escalated urgently. The evidence points the same way throughout: the earlier it is given, the better the outcome. Delay is what turns an incident into an injury.
Certain areas carry higher risk because they sit along major arterial pathways. The area between the brows, the folds running from nose to mouth, the nose itself and the hollow beneath the eye are the principal ones. Risk rises with large volumes, with sharp needles rather than blunt cannulae, with deeper injection planes, and with high injection pressure. This is why an injector’s understanding of facial vascular anatomy is not a credential to display but a thing they use on the day.