A new tool to treat the chronically occluded coronary artery?

The chronic total occlusion (CTO) remains one of the most challenging of coronary lesions to treat percutaneously. There is compelling evidence that in patients with viable territory distal to the CTO, revascularization can improve symptoms, such as exercise capacity, ventricular function, and possibly lengthen life [1,2]. Thus exploration of methods to improve the outcome of percutaneous treatment merits serious investigation. Success rate for treating CTO percutaneously lags behind other coronary subsets. Utilizing conventional guide wires and balloons may allow success in 50– 75% of lesions [1]. Previously studied dedicated devices such as the laser wire, radiofrequency guide wire, ultrasound vibrational system, or blunt microdissection may be effective in upwards of 50% of lesions unsuccessfully attempted by conventional methods [3]. Thus, overall success rates may increase to 60–80% adding a dedicated adjunctive device. Clinical acceptance of these devices has been limited in part by the relatively high incidence of major adverse clinical events particularly troubling with most devices, a relatively high incidence of coronary perforation. The optimal technique with all these new devices requires trial-anderror application in patients. As such, the relatively high incidence of complications may be related to the learning curve in addition to, or rather than, limitations of the device. Alternative to the dedicated CTO devices is the extension of conventional equipment with new techniques for antegrade and retrograde approach and use of specialized CTO guide wires, which can exert greater force and/ or are tapered to more effectively puncture the hard cap of the CTO. With these techniques, pioneered by Japanese investigators, success rates have been reported as high as 80–90% [4]. These approaches require great patience, time, and skill. Solutions to treat CTO may ultimately fuse the use of specialized devices, such as the one discussed in the article by Chamie et al. [3] with innovative techniques such that CTO success rates may compare favorably to other coronary subsets. In the current study, Chamie et al. have described their results using a new CTO device in a first-in-man study [3]. The device is described as a penetrating guide wire with 12g force using ‘‘mechanically rotating-oscillating power. ’’ No further technical details are available from the article or from the company website. Consecutive patients were included if after 5 min of ‘‘good-faith’’ effort to cross the CTO with a conventional guide wire, the CTO could not be crossed (16 of 31 patients). Conventional approach success was 45.2%, somewhat lower than the most contemporary experiences. The new device was successful in 10 of 16 patients (62.5%). As such, the addition of this device to the conventional methods increased the overall success rate in opening CTO in this series to 77%. There was one serious coronary perforation (incidence of 6.3%) which required percutaneous treatment. The authors conclude that the device is technically feasible to use, safe, and effective in this first-in-man experience. This initial report, to be sure, urges further study of this device. It also stimulates many questions about its potential value. The average time of device usage was 34 min. Would the success rate using conventional techniques have been higher (and the need for the device less frequent) if rather than allowing the device use after a 5 min conventional guide wire attempt, conventional guide wire time was extended to 15, 20, or 30 min? (or would the complication rate with convention approach simply have increased? ) Is the perforation rate of 6.3% a function of the learning curve or is it part and parcel of device application? What is the mechanism of device efficacy? Is it simply the increased time manipulating a high-force wire through the fibrous cap, is it due to some aspect of the