Effect of Diameter of Drug-Eluting Stents Versus Bare-Metal Stents on Late Outcomes: a propensity score-matched analysis

Introduction: Drug eluting stents (DES) have been shown to reduce major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI), as compared with bare-metal stents (BMS). However, the benefits of the use of DES remains uncertain for large diameter stents. We therefore aimed to compare outcomes of DES and BMS for small and large diameter stents separately.

Methods: we evaluated 12785 consecutive patients who underwent PCI from April 2004 to August 2014. Median follow up was 6.4 years. Propensity score matching analysis was used to identify 3119 pairs of patients with at least one small diameter stent (< 3.5 mm), and 817 pairs of patients with large stents only (≥ 3.5 mm). Performance of DES versus BMS was compared separately in each group. Outcomes included all cause death, MI, target vessel revascularization and coronary artery bypass grafting.

Results: mean age in the large and small stent diameter groups was 68±12 and 69 ±12 years respectively (p<0.001) and female gender was 18% and 25% respectively (p<0.001). Acute cases (i.e. MI or ACS) comprised 63% and 60% (p=0.016) and STEMI cases 9% and 6.6% (p<0.001) of large and small diameter stents respectively. After performance of propensity score matching, the placement of a large diameter stent BMS was associated with higher death rate (HR 1.49; 95 CI: 1.28-1.74; p<0.0001), higher rate of re-MI or death (HR 1.49; 95 CI: 1.3-1.71; p<0.0001) and higher rate of PCI or CABG (HR 1.5; 95 CI: 1.5 1.28-1.75; p<0.0001) as compared with DES In small stents. However, there was no significant difference in outcomes between BMS and DES in larger stents (figure).

Conclusion: in this current propensity score matched registry based , long term outcomes were better with DES as compared to BMS when small stents were used but not when only large diameter stents were used.