Implants, even giant ones, don't require blood flow. The whole point of them is that they're inert insofar as the body is concerned (ideally, anyway). So, in some earlier pix of Chelsea, her veins weren't nearly so prominent (didn't someone once post pre or early (small) implant pix of her some time ago) thus it's reasonable to assume that the huge implants, or the surgeries required to install/adjust them has made the veins appear considerably more prominent. Fortunately for her, there are plenty of guys out there (obviously) who dig that sort of thing...