For both of the PCI case volume specific structural measures, existing standards encourage reporting.24 However, although the experi- ence of the operator and the hospital performing PCI has been associated with improved outcomes, it is not clear what spe- cific threshold volume of PCI cases represents a true clinically important indicator. Thus, the intent of these case-volume mea- sures is to encourage data collection rather than specific targets. In addition, the writing committee recognizes the unique chal- lenges of accurately documenting operator volume because some data systems cannot capture data for operators who work at multiple sites, and self-reporting can have limitations. Given the challenges in capturing the required data, the limitations of the evidence supporting a specific threshold for operator volume, and the potential for unintended consequences, the writing committee designated the operator volume metric for use only in internal quality improvement because it does not comply with all the desirable attributes required (see Table 4 and footnotes to Table 1). The writing committee believes it is important to encourage tracking of operator volume, but it would not be appropriate to evaluate operators on the basis of volume of procedures alone, so this measure should not be used in accountability or public reporting programs. 5. Measures Included in This Set 5.1. Comprehensive Documentation of Indications for PCI Comprehensive documentation of the indication for PCI is an absolute requirement for performing the procedure. This should include an appropriate description of the key features of the clinical presentation, along with documentation of noninvasive stress testing and functional assessments (if clinically indicated and performed) and the severity of angiographic stenosis for the treated lesion. PCIs are performed to improve symptoms or sur- vival. 