Incomplete stent apposition after implantation of paclitaxel-eluting stents or bare metal stents: insights from the randomized TAXUS II trial.

BACKGROUND: The clinical impact of late incomplete stent apposition (ISA) for drug-eluting stents is unknown. We sought to prospectively investigate the incidence and extent of ISA after the procedure and at 6-month follow-up of paclitaxel-eluting stents in comparison with bare metal stents (BMS) and survey the clinical significance of ISA over a period of 12 months. METHODS AND RESULTS: TAXUS II was a randomized, double-blind study with 536 patients in 2 consecutive cohorts comparing slow-release (SR; 131 patients) and moderate-release (MR; 135 patients) paclitaxel-eluting stents with BMS (270 patients). This intravascular ultrasound (IVUS) substudy included patients who underwent serial IVUS examination after the procedure and at 6 months (BMS, 240 patients; SR, 113; MR, 116). The qualitative and quantitative analyses of ISA were performed by an independent, blinded core laboratory. More than half of the instances of ISA observed after the procedure resolved at 6 months in all groups. No difference in the incidence of late-acquired ISA was observed among the 3 groups (BMS, 5.4%; SR, 8.0%; MR, 9.5%; P=0.306), with a similar ISA volume (BMS, 11.4 mm3; SR, 21.7 mm3; MR, 8.5 mm3; P=0.18). Late-acquired ISA was the result of an increase of vessel area without change in plaque behind the stent. Predictive factors of late-acquired ISA were lesion length, unstable angina, and absence of diabetes. No stent thrombosis occurred in the patients diagnosed with ISA over a period of 12 months. CONCLUSIONS: The incidence and extent of late-acquired ISA are comparable in paclitaxel-eluting stents and BMS. ISA is a pure IVUS finding without clinical repercussions.

The effect of stent coating on stent deliverability: direct randomised comparison of drug eluting and bare metal stents using the same stent platform.

BACKGROUND: There is certain experimental and clinical evidence indicating that the covering of bare metal stents (BMS) with drug eluting polymers to produce drug eluting stents (DES) results in increased stent stiffness and modifies the mechanical properties of the stent platform. In addition, it has been speculated that the mechanical performance of DES, compared to BMS, may be related to the type of polymer used to cover stents. AIM: We aimed at evaluating the deliverability of DES with a lactate based biodegradable polymer and BMS in patients with stable coronary artery disease in a prospective randomised study. METHODS: One hundred eleven consecutive patients (age: 36-77, mean 58.8 years) scheduled for routine angioplasty due to stable coronary disease were randomised to receive BMS (Chopin II(TM), Balton, Poland) or paclitaxel eluting stent (Chopin Luc(TM), Balton, Poland) using the same metal platform. Only patients scheduled for angioplasty using the direct implantation technique of a single stent were randomised. The exclusion criteria included patients 〉 80 years, multivessel disease and reference diameter of the target vessel 〉 3.5 mm. RESULTS: In the BMS group (n = 55; 35 males and 20 females), the mean diameter of implanted stents was 3.09 ± 0.40 and the mean length was 11.37 ± 2.80, whereas in the DES group (n = 56; 34 males and 22 females) the mean stent sizes were 3.02 ± 0.34 and 17.90 ± 7.38 mm, respectively (p 〉 0.05 for length). The groups did not significantly differ regarding the frequency of stent implantation to particular coronary vessels. The direct stenting technique was attempted and failed, leading to the stents' implantation after predilatation in five patients in the BMS group and six patients in the DES group. Failure of stent implantation and subsequent implantation of another stent type was observed in no BMS patients and in one DES patient (NS). CONCLUSIONS: Although stent covering with lactate based drug eluting polymer may increase its stiffness, it does not affect its deliverability in patients with stable coronary disease.