1610S ince the introduction of hypothermic circulatory arrest for aortic arch surgery in 1975, 1 there has been considerable progress in addressing this complex surgical pathology. [2][3][4] However, the rapidity with which operative techniques have evolved has outpaced methodical appraisal of their clinical merit, leaving behind a wealth of perfunctory data. In particular, existing emphasis on neurological outcomes has neglected other critical end points, whereas inconsistent definitions and reporting formats limit the applicability of the results of some studies. Robust comparisons between institutional reports are therefore difficult, restricting critical appraisal and summary of existing surgical approaches.The International Aortic Arch Surgery Study Group (IAASSG) has been formed to enable multi-institutional collaboration to better explore the impact of surgical techniques on patient outcomes, using uniform definitions of events and clinical end points. A key endeavor is to standardize reporting formats to facilitate effective comparisons. Such a concerted effort, with the combined expertise of leading academic surgeons, paves the way for a unified language specific for aortic arch surgery that promotes closer cooperation and systematic evaluation and is essential in forming a framework of existing knowledge and guiding progress and research for the future.
5,6The IAASSG has devised a management-orientated classification system for significant clinical end points specific for aortic arch surgery and has undertaken a consensus survey of leading arch surgeons. The following report describes this classification scheme and reports the results of the consensus.
Methodology Rationales of the Grading SystemA management-oriented classification system for complications, which grades adverse events by severity on the basis of the management required, is simple, reproducible, and comprehensive.7 It avoids duplication of overlapping results and limits the fluctuating ratings of negative outcomes between institutions by providing standardized definitions. 7,8 Stratifying the severity of relevant complications into grades allows more thorough analysis to be achieved to assist benchmarking of existing procedures, identifying areas in need of improvement, guiding prospective research, and evaluating the effectiveness of interventions. Such an approach has been used widely 7 and has been successfully validated by several subspecialties and procedures. [9][10][11][12][13][14] Variants of this approach have also been implemented for thoracic surgery, resulting in a feasible system that facilitates objective assessments and identifies the burden of individual complications. 15,16 Following the work by Dindo and coworkers, 7 we propose the following system for grading adverse outcomes specific for aortic arch surgery (Table 1). Clinical complications are stratified into 5 major grades, from those that are self-limiting or