After completing medical school in Cardiff, Dev trained in cardiology and general medicine in Wales and Edinburgh. During this period he was awarded a BHF junior research fellowship at Cardiff University and was subsequently awarded his MD. Having developed an interest in preventative cardiology and vascular medicine, he then completed training in medical biochemistry and metabolic medicine in Cardiff, which included training at the Imperial Weight Centre, Charing Cross Hospital. He was appointed as a consultant in 2011.
He is clinical lead for the lipoprotein apheresis service in Cardiff and is medical lead for FH Wales, the Welsh Familial Hypercholesterolaemia cascade testing service. He runs a clinical nutrition service addressing medical complications of eating disorders and is clinical lead for the specialist weight management service in Cardiff. His research interests are in FH and vascular biology. Dev is course director for the distance learning MSc in Preventative Cardiovascular Medicine at University of South Wales.