Value and limitations of target-vessel ischemia in predicting late clinical events after drug-eluting stent implantation

Drug-eluting stents reduce clinical events related to restenosis but may be complicated by late stent-thrombosis. Whereas assessment of target-vessel ischemia by myocardial perfusion scintigraphy identifies relevant restenosis noninvasively, it is unknown whether this technique may also predict late clinical events related to late stent-thrombosis and to restenosis after drug-eluting stent implantation. METHODS: All 826 patients treated with stenting between May 2003 and May 2004 were included in the Basel Stent Cost Effectiveness Trial (Basel Stent Kosten-Effektivitäts Trial, or BASKET) and randomized (2:1) to drug-eluting stents or bare metal stents. Myocardial scintigraphy was performed on 476 (64%) of 747 patients without major events after 6 mo. Patients were followed for 1 y for cardiac death, nonfatal myocardial infarction, and target-vessel revascularization due to restenosis or late stent-thrombosis. RESULTS: The rate of target-vessel ischemia in these patients was lower with drug-eluting stents than with bare metal stents (5.4% vs. 10.4%, P = 0.045), similar to the rates of symptom-driven target-vessel revascularization up to 6 mo (4.6% vs. 7.8%, P = 0.08). Ischemia was silent in 68%. During follow-up, patients with target-vessel ischemia had higher event rates than did patients without ischemia (32.4% vs. 6.1%, P > 0.001); however, ischemia did not predict late stent-thrombosis (0/11 cases). CONCLUSION: The rate of clinical restenosis assessed scintigraphically was lower with drug-eluting stents than with bare metal stents and paralleled that of symptom-driven target-vessel revascularization. Target-vessel ischemia independently predicted late clinical events related to restenosis but not to late stent-thrombosis.