Mortality rate would be incredibly low, probably lower that the risk of just getting to the doctor's office. The morbidity/complication rate should be slightly less than IV sedation or general anesthetic due to their additives risk. Possible complications resulting from gynecomastia surgery are not frequent but include -Asymmetry during the healing processLumps or firmness under skinProlonged swelling (edema)Skin Pigment changesProlonged redness of the incisionLoss of Nipple/AreolaInfection#GynecomasticComplicationRate
I prefer to use sedation or general for excision of male gynecomastia. The risks or mortality are extremely low, and morbidity like infection, fluid collection, skin loss, etc.. is pretty low.