Adverse event risk lasts at least 5 years with sirolimus-eluting stents
MedWire News: Late adverse events such as very late stent thrombosis (ST) and late target lesion revascularization (TLR) pose a threat to patients for at least 5 years after implantation of a first generation drug-eluting stent (DES), Japanese study data show.
"Despite lingering concerns on DES-related late adverse events, there is a scarcity of longer-term data from large-scale DES registries with adequate statistical power to evaluate low-frequency events such as ST, note Takeshi Kimura (Kyoto University) and colleagues.
To address this, Kimura and team evaluated 5-year clinical outcomes among 12,812 consecutive patients undergoing sirolimus-eluting stent (SES) implantation and registered in the j-Cypher registry in Japan.
As reported in the journal Circulation, cumulative incidence of definite ST was low, at 0.3% on day 30, 0.6% at 1 year, and 1.6% at 5 years.
Even though the overall incidence was low, late and very late ST continued to occur at a constant rate of 0.26% per year, without attenuation, for up to 5 years after SES implantation.
Cumulative incidence of target lesion revascularization (TLR) within the first year was also low, at 7.3%. However, as with late ST, late TLR (beyond 1 year) continued to occur without attenuation, at a rate of 2.2% per year, for up to 5 years; the cumulative incidence of TLR at this point was 15.9%.
The researchers say the independent risk factors for early, late, and very late ST differed among the groups. This suggests the "presence of different pathophysiologic mechanisms of ST according to the timing of ST onset," they write.
Specifically, acute coronary syndrome and a target of proximal left anterior descending coronary artery were risk factors for early ST at hazard ratios (HRs) of 2.34 and 1.99, respectively.
Side-branch stenting (HR=6.01), diabetes mellitus (HR=3.86), and end-stage renal disease with (HR=5.63) or without hemodialysis (HR= 3.83) were risk factors for late ST, while current smoking (HR=2.04) and total stent length greater than 28 mm (HR=1.58) were risk factors for very late ST.
Independent risk factors for late TLR were generally similar to those identified for early TLR and included hemodialysis, total stent length greater than 28 mm, age below 80 years, peripheral vascular disease, diabetes mellitus, target of in-stent restenosis, male gender, and target of chronic total occlusion.
"Because we have not observed yet attenuation of the annual incidences of very late ST and late TLR at 5 years after SES implantation, we should continue to evaluate longer-term outcome beyond 5 years to fully estimate the magnitude of problems associated with use of SES," Kimura and co-authors conclude.
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By Laura Dean