Summary of the most common response clusters with exemplary responses

Response Cluster^{^a}	Explanation	Exemplary Responses^{^a}
General advice
Humility and ethical standards	Realistic appraisal of one’s skillset and its limitations	“We need calm and honest fellows, not cowboys”“Be aware of overestimating your own skills”
Interaction with colleagues and asking for advice	Reaching out for advice and help from more experienced colleagues when needed	“Don’t be a hero—stop and ask!”“Be comfortable referring for a second opinion”
Critically revisiting complications and their management	Discussion of complications with colleagues in and outside M&M rounds and meetings, constructive feedback, root-cause analysis	“Show fellows their own complications and deaths, and how to deal with them if there was a second chance”“Honestly self-review all cases in which [a] complication has occurred and understand what went wrong. Never blame it on device quality or malfunction”
Preprocedural phase
Indication and patient selection	Patient-centered treatment decision-making, knowing which patients one should not treat	“Learn when to say no”“What not to treat in the first 3–5 years of practice”“Knowing which patients can be safely followed”
Preoperative planning	Thorough review of prior imaging, a priori planning of specific procedure steps, anticipation of potential problems and alternative solutions	“Study the 3D angio, don’t rush, plan your approach. What’s the plan B, C?”“Work-up each case very carefully and try to predict complications”“Before doing a procedure, think of everything that can induce a procedural complication”
Keeping alternative treatment options in mind	Considering surgical options (clipping, sacrificing the parent vessel) and watch-and-wait strategies	“Less emphasis on endovascular being the be-all and end-all”“Never forget that competent and adequate surgical clipping is feasible and sometimes ideal!”
Theoretic knowledge	Solid knowledge about cerebrovascular anatomy	“Be properly trained, both technical and theoretical!, before you start.”“More training in some programs on how to look at imaging”
Intraprocedural phase
Technical skills	Acquiring technical skills in a simulation environment before performing real cases	“Always be careful with patients and train a lot in silicone models/computer simulators!!”“Simulators are how you need to learn and master the nuances of different cases, not trial and error on patients”
Standardization and simplification	Standardization of procedure steps, prespecified protocols for the management of complications	“Stick to the given protocols each and every time”“Meticulous planning of the procedure”“Show all types of possible complications and write protocols for how to deal with them”
Knowing when to stop	Recognizing the point at which continuing the procedure will likely cause more harm than benefit, avoiding the “perfection trap”	“If you think that you can put one more coil, that is [the] time to stop!”“Don’t let the best be the enemy of the good”“How to reduce unnecessary and perfectionist steps”

Note:—M&M indicates morbidity and mortality.
↵a For a detailed overview of response clusters and individual responses, see the “Affinity Diagram” in the Online Appendix.