A device for detecting a hematoma or subcutaneous hemorrhage after a PCI, which includes a bandage provided with fastening elements for its placement at the PCI access site, and the use of a safety bandage for producing the same. In the device, the bandage includes a flexible and, in its longitudinal direction, non-elastic element connected to a strain sensor so arranged that the strain sensor, when the element after the placement of the bandage at the access site is subjected to a change in tension as a result of a hematoma or subcutaneous hemorrhage after the PCI, emits a signal that is indicative of the hematoma or hemorrhage.