Study patients treated with pPCI are randomized to pretreatment with rPerC or no pretreatment (control group). The randomization will take place in the ambulance or at the local hospital. With the aim of not causing unnecessary delays, the pretreatment is discontinued if the patient arrives at the cath. lab. before the pretreatment is completed.The discomfort in connection with the pretreatment has been shown to be minimal.