In a blood pump system comprising a blood pump (50) and an intravascular flow cannula (53), a pressure sensor (30) is arranged within the flow cannula and, with respect to the flow cannula's longitudinal axis (1), at a level of the blood flow through opening (54) or bordering the blood flow through opening (54). By this arrangement, the pressure sensor (30) can be used to safely detect with great accuracy both the pressure outside the flow cannula (53) and the fact whether a blood vessel wall is sucked against the blood flow through opening (54).
