What is the difference between vascular experts and venous experts?

A venous expert is someone who specialises just in veins. A vascular expert is someone who specialises in vessels (and those vessels may be arteries or they may be veins). Most vascular specialists do some venous work, but most of their career is spent treating arterial disease. If you’re going to have your veins treated, it is important that you see someone who just specialises in treating veins.