Table 1. Clavien system for the classification of negative outcomes in general surgery and solid organ transplantation (adapted from references 8–10).

Grade 1	Any alteration from the ideal postoperative course, with complete recovery or which can be easily controlled and which fulfills the following general characteristics:
	(a) Not life threatening
	(b) Not requiring use of drugs other than immunosuppressants, analgesics, antipyretics, antiinflammatory agents, antiemetics, drugs required for urinary retention or lower urinary tract infection, arterial hypertension, hyperlipidemia or transient hyperglycemia
	(c) Requiring only therapeutic procedures that can be performed at the bedside
	(d) Postoperative bleeding requiring ≤3 units of blood transfusion
	(e) Never associated with a prolongation of ICU stay or total hospital stay to more than twice the median stay for the procedure in the population of the study
Grade 2	Any complication that is potentially life threatening or results in ICU stay >5 days, hospital stay >4 weeks for the recipient, but which does not result in residual disability or persistent disease
Grade 3	Any complication with residual or lasting functional disability or development of malignant disease
Grade 4	Complications that lead to retransplantation (grade 4a) or death (grade 4b)