Abstract: A balloon catheter for medical applications has a balloon 11 in a tip region facing the patient having a structured outer surface 12. The structured outer surface 12 is formed by wave troughs and wave crests which are not connected to each other. The structured outer surface 12 of a balloon 11 can cling to adjacent surfaces. The balloon catheter is introduced via a left-ventricular cardiotomy in the tip region and inserted into the aorta ascendens. The balloon 11 occludes the aorta ascendens. The balloon allows cardioplegia to be performed and relieves the heart through suctioning-off. Particular applications for the balloon catheter include by calcification of the aorta ascendens, for effecting LIMA/RIMA-anastomoses, and when effecting venovenostomies.