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In current device trials, the values of angiographic late lumen loss (LLL) have become extremely low and the relationship between LLL and clinical endpoints has not been recently re-evaluated. The impact of LLL on target lesion revascularization (TLR) in a patient- and study-level analysis of contemporary coronary devices was investigated.We performed a patient-level meta-analysis of seven randomized controlled trials including 2426 patients treated with first- and second-generation drug-eluting stents (DES) and a study-level meta-analysis of 40 studies including 19 199 patients treated with CE-marked DES. In the patient-level analysis, the probability regression curve showed an exponential relationship between in-stent LLL and 2-year incidence of TLR. The optimal cut-off value of LLL based on Youden's index for 2-year TLR event was 0.50 mm. In the Cox proportional hazard model, LLL >0.50 mm was independently associated with an increased incidence of TLR up to 4 years after angiographic follow-up {adjusted hazard ratio (HR) 6.62 [95% confidence interval (95% CI) 4.67-9.39], P < 0.001}. In the meta-regression analysis of the DES studies, pooled mean value of LLL was as low as 0.23 mm (95% CI 0.20-0.26), and there was a moderate correlation between the 1- and 5-year incidence of TLR and the percentage of the lesions with LLL >0.50 mm (R2 = 0.44, P < 0.001 at 1 year, R2 = 0.40, P < 0.001 at 5 years).An angiographic LLL ≤0.50 mm was not predictive of the incidence of TLR whereas a LLL >0.50 mm was. Low LLL in contemporary device trials may not be a sufficiently discriminating parameter for the comparative evaluation of devices.
Background There are no data comparing sirolimus-coated balloons (SCBs [MagicTouch, Concept Medical]) to paclitaxel-coated balloons (PCBs [SeQuent Please Neo, B. Braun]) for the treatment of de novo small vessel disease (SVD). Objectives This study sought to compare quantitative coronary angiographic outcomes at 6 months after treatment of de novo SVD with a PCB or SCB. Methods This prospective, multicenter, noninferiority trial randomized 121 patients (129 SVD lesions) to treatment with an SCB or PCB, with balloon sizing determined using optical coherence tomography. The primary endpoint was noninferiority for the 6-month angiographic net lumen gain. Results Angiographic follow-up was completed in 109 (90.1%) patients in the per-protocol analysis. The mean ± SD angiographic net gains were 0.25 ± 0.40 mm with SCBs vs 0.48 ± 0.37 mm with PCBs, resulting in SCBs failing to meet the 0.30 mm criterion for noninferiority (P noninferiority = 0.173), with an absolute difference of −0.23 mm (95% CI: −0.37 to −0.09) secondary to a smaller late loss (0.00 ± 0.32 mm vs 0.32 ± 0.47 mm; P < 0.001) and more frequent late lumen enlargement (53.7% vs 30.0%; OR: 2.60; 95% CI: 1.22-5.67; P = 0.014) with PCBs. Binary restenosis rates were 32.8% and 12.5% following treatment with SCBs and PCBs, respectively (OR: 3.41; 95% CI: 1.36-9.44; P = 0.012). The mean angiography-derived fractional flow ratio at follow-up was 0.86 ± 0.15 following treatment with SCBs and 0.91 ± 0.09 following PCBs (P = 0.026); a fractional flow ratio ≤0.80 occurred in 13 and 5 vessels after treatment with SCBs and PCBs, respectively. Conclusions The SCB MagicTouch failed to demonstrate noninferiority for angiographic net lumen gain at 6 months compared to the PCB SeQuent Please Neo.
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The aims of this study are to generate experimental data and develop numerical models for aluminum alloy continuous beams, and to utilize the results to underpin the development of revised design methods for indeterminate structures. This paper presents an experimental program and finite-element (FE) analyses for two-span continuous beams (i.e., five-point bending) of square and rectangular hollow sections (SHSs and RHSs). The experimental program comprised 27 five-point bending tests with three different positioning of loads. The testing procedures and key results are reported. The test specimens were manufactured by extrusion, with 18 of grade 6061-T6 and 9 of grade 6063-T5 heat-treated aluminum alloys. The test specimens were nonslender sections, and mostly of Class 1 proportions. Generally, the specimens failed by the formation of a collapse mechanism comprising three plastic hinges. The distances between the supports and the loading points were varied in order to form the first plastic hinge in different locations, to achieve different load levels between the first hinge and collapse, and to change the rotation demands on the first hinge that formed. The FE models were developed and failure was defined as either when a plastic collapse mechanism was formed or the material fracture strain was reached on the tension flange, whichever occurred first. The numerical models were first validated against the experimentally obtained load-deflection responses, as well as the failure modes. The experimental and FE ultimate loads were both found to be beyond the theoretical loads corresponding to the formation of the first hinge as well as the calculated plastic collapse loads. A key characteristic of aluminum alloy, strain hardening, is shown to be particularly significant in both the experimental program and the numerical investigation. The validated FE models are used to generate numerical results through parametric studies in the companion paper. The development of design rules for indeterminate aluminum alloy structural systems is then described.
