Obesity is associated with type 2 diabetes (T2D) and cardiovascular disease (CVD). Metabolic and bariatric surgery (MBS) has in several randomized controlled trials (RCT) been shown to be superior to best medical therapy in the treatment of T2D. In the area of CVD, RCT after MBS are lacking. It was recently demonstrated in a cohort study that MBS in patients with severe obesity and a previous myocardial infarction (MI) was associated with a 50% reduction in the risk of death and new MI. The aim of this proposal is to confirm this in a nationwide RCT. Using the nationwide SWEDEHEART database patients with severe obesity and a previous MI will be identified. They will be contacted and offered participation. After informed consent the patients will be randomized to MBS or optimized care (including visit with a cardiologist and optimization of secondary preventive measures and referral to dietician/physiotherapist). The primary outcome measure is a major cardiovascular adverse event (MACE). Secondary outcome measures include mortality, new MI, stroke, heart failure and atrial fibrillation. Tertiary outcome measures include health related quality of life and surgical complications. Patients will be followed in the nationwide metabolic surgery register SOReg, the national inpatient register, national cause of death register, the Swedish prescribed drug register, and the Swedish population register. If positive results these can be included in guidelines for MBS.