Percutaneous Revascularization of Chronic Total Coronary Occlusion

Although chronic total occlusion (CTO) of a coronary artery is a common finding,1 there is little consensus as to whether such lesions should be treated routinely by percutaneous coronary intervention (PCI). Benefits of successful CTO PCI include relief of symptoms, resolution of ischemia, improvement in left ventricular function, and avoidance of coronary bypass surgery.2 Conversely, unsuccessful CTO PCI is common, and there are several potential adverse consequences associated with attempting PCI of a CTO. Early in the learning curve, procedures tend to be longer with increased contrast and radiation exposure to the patient.3,4 Coronary perforation is also more frequent with CTO attempts than non-CTO lesions and may be associated with cardiac tamponade, need for emergency surgery, and death.5 Rates of successful CTO are variable and highly dependent on operator skill and experience. Traditional technical success rates range between 60% and 75%,2,6 much lower than rates for non-CTO lesions. In the current era, however, with contemporary techniques and with operators with expertise in CTO PCI, success rates of 80% to 90% have been achieved.5,7Lack of success can be attributed to procedural challenges that are specific to CTO, and accordingly, approaches unique to coronary CTO PCI have been developed. The major barrier is the inability to traverse the occluded segment with a guidewire because the composition of a CTO includes fibrotic, calcified tissue with no well-defined lumen.CTO PCI requires different equipment compared with standard PCI. Large lumen guide catheters together with extra long sheaths are essential to provide sufficient backup support.8 A unique aspect of CTO PCI is the intentional use the extraluminal space of the obstructed coronary artery to gain …