Uncoverage, malapposition more likely with paclitaxel-eluting than bare metal stents
MedWire News: ST-elevation myocardial infarction (STEMI) patients who undergo percutaneous coronary intervention (PCI) using paclitaxel-eluting stents (PES) have a higher 13-month risk for stent strut malapposition and uncoverage than those who receive bare metal stents (BMS), results from a HORIZONS-AMI substudy indicate.
However, the findings, published in the journal Circulation, also show reduced rates of neointimal proliferation - and thus a lower risk for vessel restenosis - among patients with PES than BMS.
Giulio Guagliumi (Ospedali Riuniti di Bergamo, Italy) and team used optical coherence tomography (OCT) to measure stent strut coverage at 13 months post-PCI among 118 STEMI patients from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) study.
All patients were randomly allocated to receive PES (n=89) or BMS (n=29) during PCI.
In all, the appearance and positioning of 44,139 stent struts (34,142 PES and 9997 BMS) in 125 lesions (93 PES and 32 BMS) were assessed at 13 months after PCI.
Guagliumi and team report a higher percentage of uncovered and malapposed stent struts in lesions treated with PES than BMS, at 5.7% versus 1.1% and 0.9% versus 0.1%, respectively (p<0.0001, p=0.0003, respectively).
Conversely, the mean percentage of vessel obstruction occurring with PES (19.2%) was almost half that of BMS (36.0%; p<0.0001).
The authors note the conflicting nature of the findings saying: "Whereas uncovered struts may increase the likelihood of primary thrombotic events at late follow-up, the reduction in restenosis with PES compared to BMS may lead to a reduction in secondary thrombotic events."
However, they add that "the fact that >94% of all struts were covered with PES at 13-month follow-up... may be considered a reassuring observation."
Guagliumi et al advise that "ongoing studies are required to determine the relationship between these OCT observations and long-term adverse clinical events."
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By Lauretta Ihonor