Incomplete revascularization is common after percutaneous coronary intervention (PCI). Whether a “reasonable” degree of incomplete revascularization is associated with a similar favorable long-term prognosis compared with complete revascularization remains unknown. We sought to quantify the proportion of coronary artery disease burden treated by PCI and evaluate its impact on outcomes using a new prognostic instrument—the Synergy Between PCI with Taxus and Cardiac Surgery (SYNTAX) Revascularization Index (SRI).