Publications

Although additive manufacturing (AM) continues to gain widespread adoption, the overhang problem remains a critical issue affecting printing quality. The design of self-supporting structures via topology optimisation approaches has been extensively studied. However, current optimisation research predominantly focuses on 3-axis AM machines, overlooking the more recently developed multi-axis machines. Moreover, the performance sacrifice due to overhang constraints in 3-axis AM can be significant, especially in structures with small volume fractions. To address this, we propose a two-step approach considering overhang constraints for multi-axis AM. This approach begins with a structure optimised using traditional topology optimisation. In the first step, a new optimisation problem determines printing surfaces for the given structure. If the proportion of unprintable elements isn't satisfactory, a second re-optimisation step is carried out to further reduce the unprintable proportion. Several examples demonstrate the effectiveness of the proposed approach. Notably, the significant performance sacrifice associated with the 3-axis AM approach becomes negligible when applying our multi-axis AM-based method.

Background— We have previously reported the safety and effectiveness of sirolimus-eluting stents for the treatment of de novo coronary lesions. The present investigation explored the potential of this technology to treat in-stent restenosis. Methods and Results— Twenty-five patients with in-stent restenosis were successfully treated with the implantation of 1 or 2 sirolimus-eluting Bx VELOCITY stents in São Paulo, Brazil. Nine patients received 2 stents (1.4 stents per lesion). Angiographic and volumetric intravascular ultrasound (IVUS) images were obtained after the procedure and at 4 and 12 months. All vessels were patent at the time of 12-month angiography. Angiographic late loss averaged 0.07±0.2 mm in-stent and −0.05±0.3 mm in-lesion at 4 months, and 0.36±0.46 mm in-stent and 0.16±0.42 mm in-lesion after 12 months. No patient had in-stent or stent margin restenosis at 4 months, and only one patient developed in-stent restenosis at 1-year follow-up. Intimal hyperplasia by 3-dimensional IVUS was 0.92±1.9 mm 3 at 4 months and 2.55±4.9 mm 3 after 1 year. Percent volume obstruction was 0.81±1.7% and 1.76±3.4% at the 4- and 12-month follow-up, respectively. There was no evidence of stent malapposition either acutely or in the follow-up IVUS images, and there were no deaths, stent thromboses, or repeat revascularizations. Conclusion— This study demonstrates the safety and the potential utility of sirolimus-eluting Bx VELOCITY stents for the treatment of in-stent restenosis.

No abstract is provided for this article.

Background— The age, creatinine, and ejection fraction (ACEF) score (age/left ventricular ejection fraction+1 if creatinine >2.0 mg/dL) has been established as an effective predictor of clinical outcomes in patients undergoing elective coronary artery bypass surgery; however, its utility in “all-comer” patients undergoing percutaneous coronary intervention is yet unexplored. Methods and Results— The ACEF score was calculated for 1208 of the 1707 patients enrolled in the LEADERS trial. Post hoc analysis was performed by stratifying clinical outcomes at the 1-year follow-up according to ACEF score tertiles: ACEF low ≤1.0225, 1.0225< ACEF mid ≤1.277, and ACEF high >1.277. At 1-year follow-up, there was a significantly lower number of patients with major adverse cardiac event–free survival in the highest tertile of the ACEF score (ACEF low =92.1%, ACEF mid =89.5%, and ACEF high =86.1%; P =0.0218). Cardiac death was less frequent in ACEF low than in ACEF mid and ACEF high (0.7% vs 2.2% vs 4.5%; hazard ratio=2.22, P =0.002) patients. Rates of myocardial infarction were significantly higher in patients with a high ACEF score (6.7% for ACEF high vs 5.2% for ACEF mid and 2.5% for ACEF low ; hazard ratio=1.6, P =0.006). Clinically driven target-vessel revascularization also tended to be higher in the ACEF high group, but the difference among the 3 groups did not reach statistical significance. The rate of composite definite, possible, and probable stent thrombosis was also higher in the ACEF high group (ACEF low =1.2%, ACEF mid =3.5%, and ACEF high =6.2%; hazard ratio=2.04, P <0.001). Conclusions— ACEF score may be a simple way to stratify risk of events in patients treated with percutaneous coronary intervention with respect to mortality and risk of myocardial infarction. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00389220.

Ethane is produced from lipid peroxidation and can be measured in the exhaled air. Cystic fibrosis (CF) is characterized by recurrent respiratory infections, release of reactive oxygen species by inflammatory cells, and increased oxidative stress. We measured exhaled ethane in 23 CF subjects (mean age +/- SEM, 21 +/- 4 yr; 10 male, FEV(1) 62 +/- 4%) and compared it with two other noninvasive markers of oxidative stress and inflammation, carbon monoxide (CO) and nitric oxide (NO). Exhaled ethane was collected during a flow and pressure-controlled exhalation into a reservoir discarding dead space air contaminated with ambient air. A sample (2 ml) of the expired air was analyzed by chromatography. Ethane levels were elevated in patients not on steroids (n = 13, 1.99 +/- 0.20 ppb) compared with steroid-treated patients (n = 10, 0.67 +/- 0.09 ppb, p < 0.01) and with 14 nonsmoking control (8 men, age 33 +/- 2.8 yr) subjects (0.82 +/- 0.40 ppb, p < 0.05). In patients not on steroid treatment ethane was correlated to airway obstruction as assessed by the ratio of residual volume to total lung capacity (RV/ TLC) (r = 0. 66, p < 0.05) and exhaled CO (r = 0.65, p < 0.05). CO concentrations were also higher in patients not on steroid treatment (3.4 +/- 0.2 ppm) than in steroid-treated patients (2.6 +/- 0.1 ppm, p < 0.05), whereas NO concentrations were not influenced by steroid treatment (3.0 +/- 0.4 ppm and 2.9 +/- 0.2 ppm, p > 0.05) and were lower than in a control group (7.0 +/- 0.4 ppb, p < 0.05). Exhaled ethane is elevated in CF, reduced in steroid-treated patients and correlates with CO and RV/TLC; therefore, it may be a useful noninvasive marker of oxidative stress.

Background and aims Whether coronary calcification is correlated with plaque/media shrinkage (PS) remains unclear. The aim of this study was to assess the relationship between the calcification process and PS, combining serial optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in vessels treated with bioresorbable vascular scaffolds (BVS). Methods In 15 patients (16 vessels), OCT and IVUS images were matched using anatomic landmarks at post-procedure and five years. PS was defined as relative decrease in plaque/media area >5%. The association between the calcification process and PS was investigated. Mixed effect models were used to assess correlations and changes over time. Results Seventy-two OCT and IVUS paired cross sections in- and out-scaffolded segments were matched at baseline and follow-up (432 images). In total, 35 out of the 72 cross sections showed PS, and 37 cross sections showed no PS (non-PS) at 5-year follow-up. Delta (Δ) plaque/media area showed negative correlation with Δ OCT calcium area (r = −0.29, p = 0.004), Δ OCT calcium arc (r = −0.42, p < 0.001), Δ OCT calcium length (r = −0.5, p < 0.001), and Δ IVUS calcium arc (r = −0.31, p = 0.024), respectively. On echogenicity analysis, Δ plaque/media area was positively associated with Δ hypoechogenic area (r = 0.47, p = 0.002). An increase in calcium area was negatively correlated to Δ hypoechogenicity (r = −0.29, p < 0.016). The increase in calcium area was positively correlated with Δ lumen area (r = 0.24, p = 0.044). Conclusions In segments treated with BVS, the calcification process was associated with PS, decrease in the hypoechogenic tissue and late luminal enlargement. Combining IVUS and OCT provides a unique method to assess the correlation between the calcification process and plaque/media shrinkage.

Culture independent techniques have allowed a better understanding of association between tobacco-smoke exposed COPD (TS-COPD) &amp; lung microbiome, but there is limited knowledge about lung microbiome in non-smoker COPD (NS-COPD) subjects. We aimed to study lung microbiome in smoker &amp; non-smoker COPD subjects and its association with lung function in rural Indian subjects. Induced sputum samples were obtained from 11 healthy-nonsmokers (H-Nonsmokers), 10 healthy-smokers (H-Smokers), 18 biomass-smoke exposed healthy (H-Biomass), 15 TS-COPD &amp; 20 NS-COPD subjects. Samples were sequenced using V3 &amp; V4 hypervariable region (Illumina MiSeq Platform) and taxanomic diversity information was obtained with QIIME pipeline, &amp; R script package. Bacterial abundance was significantly higher in NS-COPD subjects compared to H-Nonsmokers, H-Biomass, &amp; TS-COPD subjects (Fig.1A). Exposure to tobacco-smoke caused decrease in bacterial diversity (Fig.1B). <i>Firmicutes</i>, <i>Bacteriodetes</i>, <i>Proteobacteria</i>, <i>Actinobcater</i> &amp; <i>Fusobacter</i> were the most prevalent phyla in our samples. Phylum <i>Proteobacteria</i>, which includes many pathogens showed higher abundance in COPD subjects (Fig.1C) &amp; were negatively associated with lung function (Fig.1D). The impaired lung function observed in COPD is associated with in increased abundance of pathogenic microbiome &amp; a decline in its diversity, which may have implications in COPD pathophysiology.