Apparatus (10) is provided, which includes an endovascular stent-graft (20) and a heating device (22) that is coupled to the stent-graft (20). The stent-graft (20) is configured to be implanted in at least one blood vessel in a vicinity of an aneurysm (102). The heating device (22) is configured to apply, to a region (24) external to the stent-graft (20), thermal energy sufficient to coagulate blood flowing into the aneurysm (102). Other embodiments are also described.