Publications

The long-term efficacy of percutaneous coronary intervention for mildly obstructive coronary narrowings is limited by the occurrence of restenosis, limiting the applicability of this therapy for these lesions. The present study reports on a consecutive series of 20 patients treated with sirolimus-eluting stent implantation for 23 angiographically mild de novo lesions (defined as a diameter stenosis <50% by quantitative coronary angiography). At a mean follow-up of 399 ± 120 days, the survival-free of major adverse events was 95%, with no patient requiring target lesion revascularization.

No abstract is provided for this article.

The differentiation between Pneumocystis carinii pneumonia (PCP) and Kaposi's sarcoma can be difficult if an HIV positive patient presents with alveolar consolidation and/or interstitial shadowing on the chest radio- graph (CXR).We have compared the CXR and thoracic computed tomographic (CT) appearances of 31 HIV positive males during acute respiratory episodes in order to evaluate the role of CT in distinguishing PCP from Kaposi's sarcoma.In group 1 sixteen patients had PCP.Eleven patients in group 2 had Kaposi's sarcoma and in group 3 four patients had both PCP and Kaposi's sarcoma.Both CXR and CT were categorised as being normal (N) or showing one or more of the following abnormalities: interstitial shadow- ing (INT); alveolar consolidation (ALV); intrapulmonary nodules < 1 cm diameter (NOD); mediastinal and/or hilar lymphadenopathy (LN); pleural effusions (EFF); cystic air spaces (C); and on CT bronchial wall thickening (BT).Results were as follows: Interstitial shadowing, alveolar consolidation and intrapulmonary nodules do not help distinguish Kaposi's sarcoma from PCP.The presence of bronchial wall thickening and cystic air spaces suggest a diagnosis of PCP whereas pleural effusions and lymphadenopathy suggests Kaposi's sarcoma.These abnormalities, which are better demonstrated by CT, help distinguish PCP from intrapul- monary Kaposi's sarcoma.N INTALVNODLNEFF C BT Group I CXR 0 14 4 1 1 2 3 0 (n= 16) CT 0 14 10 7 5 2 6 9 Group2 CXR0 9 5 5 2 7 0 0 (n= 11) C 0 O 9 5 9

Powder bed fusion (PBF) is a commonly employed metal additive manufacturing (AM) process in which components are built, layer-by-layer, using metallic powder. The component size is limited by the internal build volume of the employed PBF AM equipment; the fabrication of components larger than this volume therefore requires mechanical joining methods, such as laser welding. There are, however, very limited test data on the mechanical performance of PBF metal with laser welded joints. In this study, the mechanical properties of PBF built 316L stainless steel parts, joined together using laser welding to form larger components, have been investigated; the microstructure of the components has also been examined. 33 PBF 316L stainless steel tensile coupons, with central laser welds, welded using a range of welding parameters, and with coupon half parts built in two different orientations, were tested. The porosity, microhardness and microstructure of the welded coupons, along with the widths of the weld and heat-affected zone (HAZ), were characterised. The PBF base metal exhibited a typical cellular microstructure, while the weld consisted of equiaxed, columnar and cellular dendrite microstructures. Narrow weld regions and HAZs were observed. The PBF base metal was found to have higher proof and ultimate strengths, but a similar fracture strain and a lower Young's modulus, compared with conventionally manufactured 316L stainless steel. The strengths were dependent on the build direction – the vertically built specimens showed lower proof strengths than the horizontal specimens. The laser welds generally exhibited lower microhardness, proof strengths and fracture strains than the PBF base metal which correlated with the observed structure. This work has demonstrated that PBF built parts can be joined by laser welding to form larger components and provided insight into the resulting strength and ductility.

Objectives The aim of this study was to compare, in a large all-comer registry, the long-term clinical outcomes after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) for ostial/mid-shaft lesions versus distal bifurcation lesions in unprotected left main coronary artery (ULMCA) stenosis. Background Limited data are available regarding clinical outcomes following DES implantation at the different ULMCA sites. Methods Patients with ULMCA stenosis treated by PCI with DES were analyzed in this multinational registry. Results A total of 1,612 patients were included: 482 were treated for ostial/mid-shaft lesions versus 1,130 for distal bifurcation lesions. At a median follow-up period of 1,250 (interquartile range: 987 to 1,564) days, PCI for distal bifurcation lesions was associated with a higher incidence of major adverse cardiac events (propensity-score adjusted hazard ratio [HR]: 1.48, 95% confidence interval [CI]: 1.16 to 1.89; p = 0.001), largely because of the higher target vessel revascularization rate observed in this group as compared to the ostial/mid-shaft lesions group (propensity-score adjusted HR: 1.68, 95% CI: 1.19 to 2.38; p = 0.003). These results were sustained following propensity-score matched analysis. With regard to all-cause death and the composite endpoint of all-cause death and myocardial infarction, propensity-score adjusted analysis suggested a trend toward higher rates of these in the distal ULMCA PCI group, although this was not observed in the propensity-score matched analysis. Conclusions This study demonstrates that PCI for ostial/mid-shaft lesions is associated with better clinical outcomes than are distal bifurcation lesions in ULMCA, largely because there is a lower need for repeat revascularization in ostial/mid-shaft lesions.

Chronic total occlusions (CTO) constitute a major challenge in percutaneous coronary revascularisation (PCI). The development of new interventional strategies, the availability of purpose made tools including dedicated catheters and wires, as well as increasing expertise by the operators, have contributed to the modest success rates which today hover around 75%. Case selection is of utmost importance since failure of this high risk procedure with its typically high radiation doses, high contrast doses and increased complication rates is associated with long term adverse events. Imaging of the coronary arteries using the gold standard of invasive coronary angiography allows characterisation of the chronic total occlusion and is often able to predict the probability of successful recanalisation. Multislice computed tomography (MSCT) is increasingly being utilised as a non-invasive diagnostic imaging modality to detect coronary artery disease. Its ability to provide information on the soft tissue (including plaque) surrounding the lumen has been applied to better define the morphological features of CTOs. In fact, the amount of calcification, tortuosity and actual length of the occluded segment which are established predictors of success, are all better characterised by MSCT. Three dimensional reconstruction of the coronary anatomy and its integration with two dimensional fluoroscopy images during the actual CTO-PCI procedure may help to identify the best angiographic projection, offering a directional guide at the angiographically "missing segment". More technological advances are needed to optimise this multi-modality imaging integration. Whether this will result in better success rates for CTO-PCI is still the subject of ongoing research. It is then that we can evaluate the true benefit of the use of MSCT for CTO against the risk from excessive radiation associated with this strategy.

Objectives To explore the rate, the determinants of success, and the hemodynamic impact of balloon postdilatation (BPD) of self‐expanding transcatheter heart valves (SE‐THVs) Background BPD is commonly used to optimize valve expansion and reduce paravalvular leakage (PVL) after transcatheter aortic valve implantation (TAVI) without clearly knowing its hemodynamic benefits. Methods Patients ( n = 307) who received a SE‐THV were stratified according to whether a BPD was performed or not. Patients who received BPD were stratified according to the severity of PVL remaining after BPD into two groups: Successful BPD (≤mild PVL + BPD) and Failed BPD (moderate‐severe PVL + BPD). Results BPD was performed in 121 patients (39.4%) and was successful in 106 patients (87.6% of attempts). A ratio of the postdilatation balloon diameter to the annulus diameter ≤0.95 was an independent predictor of BPD failure (OR: 10.72 [2.02‐56.76], P = .005). Peak transvalvular pressure gradient (PG) was lower in the Successful BPD group (14[12‐22] mm Hg) than in the Failed BPD group (18[16‐23] mm Hg, P = .029), and did not rise in either group during follow‐up (median [IQR], 364[161‐739] days). Conclusion BPD was performed in 39% of patients who received a SE‐THV, and was successful in the majority of attempts. BPD failure was more likely in patients with a small postdilatation balloon‐to‐annulus diameter ratio. Effective BPD improved THV hemodynamic performance, and this was maintained in the intermediate‐term post‐TAVI.

The aim of this study was the in vivo validation and comparison of the geometric and densitometric technique of a computer-assisted automatic quantitative angiographic system (CAAS system). In six Landrace Yorkshire pigs (45 to 55 kg), precision-drilled phantoms with a circular lumen of 0.5, 0.7, 1.0, 1.4, and 1.9 mm were percutaneously introduced into the left anterior descending or left circumflex coronary artery. Twenty-eight coronary angiograms obtained with the phantom in a wedged intracoronary position could be quantitatively analyzed. Minimal lumen diameter, minimal cross-sectional area, percent diameter stenosis, and cross-sectional area stenosis were automatically measured with both the geometric and densitometric technique and were compared with the known phantom dimensions. When minimal lumen diameter was measured using the geometric approach, a nonsignificant underestimation of the phantom size was observed, with a mean difference of −0.06 ± 0.14 mm. The larger mean difference observed with videodensitometry (−0.11 ± 0.20 mm) was the result of the failure of the technique to differentiate the low lumen videodensities of two phantoms of smaller size (0.5 and 0.7 mm) from a dense background. Percent cross-sectional area stenosis measured with the two techniques showed a good correlation with the corresponding phantom measurements (mean difference between percent cross-sectional area stenosis calculated from the quantitative angiographic measurements and the corresponding phantom dimensions was equal to 2 ± 6% for both techniques, correlation coefficient = 0.93 with both techniques, SEE = 5% with the geometric technique and 6% with the densitometric approach). In an in vivo experimental setting mimicking diagnostic coronary angiography, single-plane quantitative angiography showed a high accuracy and precision in the measurement of stenosis hole phantoms with both the geometric and the densitometric approach. The failure of densitometry in the measurement of some of the most severe stenoses explains the better results obtained with the geometric technique.