Blepharoplasty and von Willebrand. Is it too risky?

Your surgeon would need to decide if the increased risk of a hematoma was warranted.  It is also essential that your surgeon work with the hematologist to make sure you are optimally managed.  Even then, there is a much higher risk of hematoma and delayed healing.  Eyelid surgery represents a much greater risk.  Bleeding and hematoma formation behind the orbital septum can lead to a retrobulbar hemorrhage with a very real and significant risk of permanent visual loss.  That can occur even when your hematologist has done every thing they can to improve the coagulation factors.  It is one thing when the eyelid surgery is medically necessary.  It is altogether another when the work is being done for cosmetic purposes.  For eyelid surgery, even an non-vision threatening hematoma can stretch out the eyelid tissue and undo the beneficial effects of surgery.

You first need to discuss this with your hematologist. For a facelift I would insist on preopertive treatment. For upper lid blepharoplasty you might not need any.