Fig. 1: Markov model, showing cost and clinical outcomes after percutaneous coronary intervention (PCI) with stenting in 6-month intervals. After initial PCI, patients are at risk of clinical restenosis over the first year. During this year, they may progress through 5 discrete health states: 1) alive with no clinical restenosis (i.e., event-free), 2) clinical restenosis as determined by the need for a subsequent coronary artery bypass graft (CABG), 3) clinical restenosis as determined by the need for repeat PCI, 4) repeat catheterization with no subsequent revascularization procedure (defined as no PCI or CABG in the ensuing 3 months) and 5) death. Restenosis is considered to occur only in the first year after initial PCI.1 Thereafter, patients have an ongoing long-term risk of death. CATH = catheterization.