Objectives: We performed a post hoc analysis of outcome in patients with, versus those without, calcified target lesions from the BASE ACS trial.Background: The outcome of contemporary stent implantation in patients with calcified lesions presenting with acute coronary syndrome is unknown.

Methods: The BASE ACS trial randomized 827 patients (1:1) presenting with acute coronary syndrome to receive either titanium-nitride-oxide-coated stents or everolimus-eluting stents. Calcified lesions were defined as moderate or severe calcification in the vessel wall by coronary angiography. The primary endpoint was major adverse cardiac events (MACE): a composite of cardiac death, non-fatal myocardial infarction or ischemia-driven target lesion revascularization. Follow-up was planned at 12 months, and yearly thereafter for up to 7 years.

Results: Of 827 patients enrolled in the trial, 352 (42.6%) had calcified target lesions. Median follow-up was 5.0 years. The incidence of MACE was higher in patients with, versus those without, calcified target lesions (19.6% vs. 12.2%, respectively, P = 0.004). This was driven by more frequent cardiac death and non-fatal myocardial infarction events (P < 0.05, both). The rates of ischemia-driven target lesion revascularization were comparable (P > 0.05). MACE and the other endpoints were comparable between the 2 propensity-score matched subgroups (P > 0.05 for all). Hypertension and smaller vessel size independently predicted MACE in patients treated for calcified lesions.

Conclusions: Patients presenting with acute coronary syndrome who were treated for calcified lesions had worse long-term clinical outcome, compared with those treated for non-calcified lesions, mainly due to more frequent safety events. In the propensity score-matched analysis, the outcome was comparable.