Abstract
Background
Although effective coverage of coronary diffuse in-stent restenosis (ISR) lesions has warranted the use of multiple drug-eluting stents, the vessel response to paclitaxel-eluting stent (PES) overlap is not fully understood.
Methods and materials
In the TAXUS-V ISR, i.e., comparing PES versus brachytherapy for the treatment of bare-metal ISR, angiographic analyses at 9-month follow-up were available in 184 ISR lesions treated with PES.
Results
In-stent late loss in entire stented segment of multiple PES ( n =50) was 0.45±0.48 mm, whereas that of single PES ( n =134) was 0.3±0.47 mm, P =.06. No aneurysm was observed at overlapping PES segments at 9 months. Stent thrombosis up to 9 months was observed in one in each group (single PES, 0.7% vs. multiple PES, 1.8%; P =.47). In a subset of 30 patients, volumetric intravascular ultrasound analysis demonstrated that in-stent net volume obstruction was 12.3±12.4 in single PES ( n =20) and 14.9±9.8 in multiple PES ( n =10), P =.60. The changes of vessel and lumen at the overlapping PES segment were similar to those of the adjacent 5-mm segments (Δminimum lumen area, mm 2 : −1.2±1.0, −1.1±1.1, −0.8±0.9, P =.48; Δvessel volume, mm 3 /mm: −0.2±1.4, 0.1±1.7, 0.3±1.3, P =.37; proximal, overlap, distal segment, respectively). There was no late incomplete stent apposition at overlapping PES segments.
Conclusions
No in vivo evidence of adverse local vessel response at the site of overlapping PES for the treatment of bare-metal ISR has been demonstrated.
1
Introduction
In-stent restenosis (ISR) is categorized as a complex lesion for percutaneous coronary interventions. While slow-release polymer-based paclitaxel-eluting stents (PES) have significantly reduced the rate of target lesion revascularization (TLR) for de novo coronary lesions , regulatory approval for use in ISR is still pending in the United States. With the drop of the usage of drug-eluting stents in 2007 due to concern about stent thrombosis, the usage of bare-metal stent (BMS) has been increased. Therefore, as the number of patients receiving BMS is rising, we are likely to come across more patients with bare-metal ISR. Complex lesions, such as ISR or diffuse disease, often require multiple stents, resulting in longer stented segments, which produced suboptimal long-term clinical outcomes in the era of bare-metal stents (BMS) . On the other hand, recent reports has suggested that implantation of multiple overlapping drug-eluting stents has a favorable risk/benefit profile for diffuse de novo coronary lesions . Intravascular ultrasound (IVUS) study from TAXUS-V (for de novo coronary lesions) and TAXUS-VI trials for overlapping PES for the treatment of de novo coronary lesions has also demonstrated that no adverse vessel response including incomplete stent apposition (ISA) at the site of the stent overlap, even though theoretically high-dose paclitaxel was delivered. Likewise, it has been reported that drug-eluting stents are equally safe and more effective than intracoronary brachytherapy for the treatment of ISR lesions . However, there is still concern about whether the implantation of multiple overlapping PES in diffuse ISR lesions damage coronary arteries.
In the first long-term preclinical study (580 days) of overlapping PES in normal porcine coronary arteries, Wilson et al. recently reported that while both the intensity and duration of inflammation were higher in overlap PES when compared to proximal or distal stented regions, inflammation was self-limiting and subsided after 180 days, and there was no evidence of dilatation or vascular instability suggestive of local toxicity. Notwithstanding evidence supporting the safety of overlapping PES in normal coronary arteries in animals, there remains a need for analysis of the vascular response to overlapping PES in human diseased coronary arteries. The present study examines the in vivo vessel reaction to multiple overlapping PES in patients with bare-metal ISR using serial angiographic and IVUS analysis.
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