A device for creating an arteriovenous (AV) fistula includes a proximal base having a distal tapered end surface and a distal tip connected to the proximal base and movable relative to the proximal base. The distal tip has a proximal tapered end surface. A first heating assembly, including an energized heating element, is disposed on at least one of the distal tapered end surface and the proximal tapered end surface. A second heating assembly, comprising a passive non-energized heat spreader, is disposed on the other one of the distal tapered end surface and the proximal tapered end surface. The distal tapered end surface and the proximal tapered end surface are adapted to contact opposing sides of a tissue portion to create the fistula. The taper of the proximal tapered end surface matches the taper of the distal tapered end surface, so that the two surfaces match one another.