These measures focused on exam- ining the core question of whether the PCI was appropriate in the context of additional therapeutic options, like medical therapy and coronary artery bypass surgery. This was an area of great interest and much discussion for the writing committee. However, in the end the group felt limited in our ability to con- struct feasible measures that could be applied reliably in clinical practice. We decided that these topics were ultimately beyond the charge of a writing committee focused on PCI. Our greatest barriers were the lack of definitive data on the risks and ben- efits of ad hoc PCI and multivessel PCI and their role in shared decision making by patients and providers.49,50 The writing com- mittee, therefore, decided that this topic might be considered in future updates of these measures or might be better handled by a writing committee focused entirely on developing performance measures for coronary revascularization (rather than just PCI). 6.2. Outcome Measures As noted previously, outcome measures are highly desirable but often difficult to incorporate into performance measure sets because of vulnerability to influences outside the provider s control. Thus, outcome measures, particularly those intended for use in accountability, should be supported by strong data and should address risk-adjustment concerns. For example, the writing committee considered a measure of the incidence of dialysis after PCI. However, this was ultimately not included because the need for unexpected dialysis after PCI is extremely rare, and when dialysis does occur after PCI, it is often in patients with marginal renal function before the PCI for whom the possibility of dialysis was discussed previously. Creating a measure in this area might dissuade these patients, who are often at high risk for coronary artery disease, from undergoing PCI. 