Background: Incomplete stent apposition (ISA) is an unusual finding of intravascular ultrasound (IVUS) that may occur both after drug-eluting stent (DES) or bare-metal stent (BMS) implantation and could be associated with late stent thrombosis. Controversy still remains about whether the risk of late-acquired ISA is increased after DES implantation. This meta-analysis aimed to clarify whether DES implantation is associated with an increased risk of late-acquired ISA.
Methods: We performed a meta-analysis from 12 randomized trials that compared DES and BMS and included IVUS follow up: TAXUS II (n = 469), TAXUS IV (n = 187), TAXUS V (n = 213) and VI (n = 147), ASPECT (n = 81), DELIVER (n = 65), SIRIUS (n = 141), DIABETES (n = 140), ENDEAVOR II (n = 250), FUTURE I and II (n = 83), and SPIRIT-I (n = 58). In these trials, 1,834 patients (972 DES, and 862 BMS) underwent immediate and follow-up IVUS examination.
Results: There was no heterogeneity among the trials (Q-test for heterogeneity: Chi2: 7.69; (p = 0.26), I2: 22%. Out of the 1,834 patients undergoing serial IVUS examination, 85 developed late-acquired ISA (4.6%). This incidence was significantly higher in DES compared with BMS (6.5% vs. 2.6%, respectively; odds ratio [OR] 2.48, 95% confidence interval [CI] 1.26 to 4.87; p = 0.008). That means that the risk of developing late-acquired ISA is 2.5 times higher after DES versus BMS implantation. No stent thrombosis occurred in the patients diagnosed with ISA over a period up to 12 months.
Conclusion: DES implantation could be associated with an increased risk of late ISA in comparison with BMS. The clinical implication of late ISA in the long term remains to be clarified.