Performance of Everolimus-Eluting versus Paclitaxel-Eluting Coronary Stents in Small Vessels: Results from the SPIRIT III and SPIRIT IV Clinical Trials

Background: Higher rates of adverse cardiac events have been observed in patients with small vessel disease. Therefore, we compared an everolimus-eluting stent (EES) to a paclitaxel-eluting stent (PES) for treatment of small (reference vessel diameter: RVD >= 2.5 mm) and larger vessels (=2.5 mm) in a pooled analysis from the SPIRIT III (n = 1,002) and SPIRIT IV (n = 3,687) trials (randomized 2:1, EES vs. PES). Methods: Data of 4,689 total patients were pooled for a patient level analysis. Lesion length, RVD, and percent diabetics were matched between stent types. EES versus PES performance was evaluated at 1 year in patients with small (n = 1,019) and larger vessels (n = 2,586) who had a single lesion treated. Results: Mean RVD assessed by quantitative coronary angiography in patients with small vessels was 2.24 +/- 0.19 and 2.25 +/- 0.20 mm in the EES and PES groups, respectively. At 1 year, EES compared to PES in small vessel patients significantly reduced major adverse cardiac events (4.5% vs. 7.9%, P = 0.04), target lesion failure (4.4% vs. 7.9%, P = 0.03), target lesion revascularization (2.4% vs. 5.5%, P = 0.02), and stent thrombosis (0.2% vs. 1.2%, P = 0.04). Relative benefits of EES versus PES were comparable in small and larger vessels (P interaction > 0.05), although the absolute benefits were greater in patients with small vessel disease. Conclusion: In high-risk patients requiring percutaneous coronary intervention in small coronary arteries, EES results in significantly improved 1-year rates of event-free survival compared to PES, with evidence present for both enhanced safety and efficacy. (J Interven Cardiol 2011;24:505-513)