Second, the writing committee considered use of a protocol for managing contrast-related nephropathy before and during Nallamothu et al ACC/AHA/SCAI/AMA-PCPI/NCQA 2013 PCI Performance Measure 939 PCI but decided that the evidence base is not substantive enough to support inclusion of such a measure at the present time. However, as discussed in Section 5.1, the writing com- mittee did elect to include documentation of preprocedural estimated GFR and contrast dose as internal quality-improve- ment measures in this set. There is a tight linkage between GFR and contrast dose and development of contrast-related nephropathy. The writing committee felt that these measures should capture, with sufficient granularity, important data to guide local improvement efforts. As the evidence base to guide the management of contrast-related nephropathy con- tinues to evolve, consideration for inclusion might be appro- priate in future iterations of this measure set. 7. Areas for Further Research The writing committee identified 4 areas of interest for fur- ther investigation. Although the areas are relevant to perfor- mance measures in general, the writing committee felt they would have particularly important implications for measure- ment with regard to PCI. Some of these have been discussed throughout the present document in relevant sections but are highlighted here for additional emphasis. 7.1. Documentation of Prescription of Drugs Versus Filling of Drug Prescriptions and Optimal Dosing of Drugs The writing committee felt that it will be important in future work to examine moving beyond documentation of only the prescription of drugs to the actual filling of drug prescriptions and the optimal dosing of drugs. Unfortunately, using existing data collection systems to measure these is currently too dif- ficult, expensive, and prone to error to serve as a useful qual- ity measure. Additionally, a patient could be seen by several practitioners who have different standards for optimal dosing. 