High procedure and patient success rates, combined with a low event rate and improved procedural characteristics, support further use of the hybrid algorithm for a broad community of appropriately trained CTO operators.

Outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) have improved because of advancements in equipment and techniques. With global collaboration and knowledge sharing, we have identified 7 common principles that are widely accepted as best practices for CTO-PCI.  1. Ischemic symptom improvement is the primary indication for CTO-PCI.  2. Dual coronary angiography and in-depth and structured review of the angiogram (and, if available, coronary computed tomography angiography) are key for planning and safely performing CTO-PCI.  3. Use of a microcatheter is essential for optimal guidewire manipulation and exchanges.  4. Antegrade wiring, antegrade dissection and reentry, and the retrograde approach are all complementary and necessary crossing strategies. Antegrade wiring is the most common initial technique, whereas retrograde and antegrade dissection and reentry are often required for more complex CTOs.  5. If the initially selected crossing strategy fails, efficient change to an alternative crossing technique increases the likelihood of eventual PCI success, shortens procedure time, and lowers radiation and contrast use.  6. Specific CTO-PCI expertise and volume and the availability of specialized equipment will increase the likelihood of crossing success and facilitate prevention and management of complications, such as perforation.  7. Meticulous attention to lesion preparation and stenting technique, often requiring intracoronary imaging, is required to ensure optimum stent expansion and minimize the risk of short- and long-term adverse events. These principles have been widely adopted by experienced CTO-PCI operators and centers currently achieving high success and acceptable complication rates. Outcomes are less optimal at less experienced centers, highlighting the need for broader adoption of the aforementioned 7 guiding principles along with the development of additional simple and safe CTO crossing and revascularization strategies through ongoing research, education, and training.

No abstract

Control over the autonomous motion of artificial nano/ micromachines is essential for real biomedical and nanotechnological applications. Consequently, a complete nanomachine should be able to be turned on and off at will. Developments over the last few years on synthetic catalytic nano/microengines and motors have enabled the harvesting of chemical energy from local molecules and transforming it into an effective autonomous motion.[1] Several impressive applications have recently reported the use of artificial micromachines for the detection of biomolecules with roving nanomotors, [2] transport of animal cells in a fluid, [3] and other microcargo delivery. [4][5][6][7] Recently, the use of a light source has been implemented to propel microparticle-based motors [8] generated by a selfdiffusiophoretic mechanism. Despite this interesting approach, the motion of the particles is limited by the dissolution of the materials and to the ultraviolet (UV) spectrum.[9] Moreover, a reversible method to start and stop the propulsion of micromotors by a visible-light source remains a challenge.Here we report the tuning of the propulsion power of Ti/ Cr/Pt catalytic microengines (m-engines) through illumination of a solution by a white-light source. We show that light suppresses the generation of microbubbles, stopping the engines if they are fixed-to or self-propelled above a platinum-patterned surface. The m-engines are reactivated by dimming the light source that illuminates the fuel solution. The illumination of the solution with visible light in the presence of Pt diminishes the concentration of hydrogen peroxide fuel and degrades the surfactant, consequently reducing the motility of the microjets. Electrochemical measurements and analysis of the surface tension support our findings. We also study the influence of different wavelengths over the visible spectrum (500-750 nm) on the formation of microbubbles.Rolled-up Ti/Cr/Pt catalytic m-engines with diameters of 5-10 mm and a length of 50 mm were prepared as described previously elsewhere [10][11][12] and in the Experimental Section.Microengines were immersed into solutions of aqueous H 2 O 2 (2.5 % v/v) as fuel and benzalkonium chloride (ADBAC) (0.5 % v/v), as the surfactant, to determine the influence of white light on the mobility of the m-engines. At lower concentrations of both chemicals, the generation of microbubbles is significantly reduced. Thus, the motility of the catalytic m-engines is controlled by a small change in the fuel (H 2 O 2 and/or surfactant) concentration. These conditions allow us to investigate a concentration range close to the metastable state, that is, where the probability of stopping the m-engines is high. Figure 1 A shows an optical microscopy image of a self-propelled mengine on a Pt-patterned silicon substrate (1 nm-thick Pt layer) placed in a Petri dish ( % 53 mm in diameter) under the illumination of a tungsten lamp (inset in Figure 1 A). The speed of the m-engines moving within the illuminated area is rapidly reduced and is zero afte...