Author + information
- Robert J. Applegate, MD∗ ()
- ↵∗Reprint requests and correspondence:
Dr. Robert J. Applegate, Wake Forest School of Medicine, Section of Cardiovascular Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157-1045.
Chronic total conclusions (CTOs) have long been considered among the most challenging lesion subsets for percutaneous coronary intervention (PCI). The basis for this belief is multifactorial, including the absence or subtlety of perceived patient symptoms, assumptions that CTOs are often associated with minimally viable or infarcted tissue, technical difficulties leading to less procedural success than for non-CTO lesions, and a lack of strong randomized clinical trial data demonstrating a benefit of PCI on clinical outcomes. Despite this prevailing notion of the limited role of PCI for CTO in contemporary practice, the relative reluctance to attempt PCI for CTOs is waning as better understanding of CTOs’ importance to the clinical outcomes of patients, improvements in device and stent design leading to more procedural success and better outcomes, and greater experience of dedicated operators have cast PCI for CTOs in a new light.
When a CTO is approached with a procedural strategy similar to that used for non-CTOs, the procedural success rate is much lower than for non-CTO PCI, often resulting in lengthy procedures and frustrated operators. The recognition that traditional single-wire techniques were not adequate to achieve high procedural success rates led to the development of newer techniques, including antegrade techniques such as multiple parallel wires, subintimal tracking with reentry (controlled antegrade retrograde tracking), and retrograde approaches taking advantage of septal and epicardial collateral channels. Although the antegrade approach has been the preferred approach for most cases and operators, the belief that skill with a retrograde approach to CTOs may result in the highest overall rates of procedural success has been gaining popularity.
The retrograde approach was introduced and developed by a group of Japanese operators who demonstrated not only the feasibility of this approach but a high procedural success rate accompanied by a low rate of procedural complications (84.8% and 1.6% overall, respectively, in the most recent registry) (1). Whether this approach and technique could be exported to other countries and operators has been the subject of ongoing study. The ERCTO (European Registry of Chronic Total Occlusion) was formed in January 2008 as a prospective registry to monitor the adoption and utilization of the PCI approach to CTOs at 16 centers throughout Europe. This group recognized the commitment required to adopt this technique as well as the need to provide a more objective basis of reporting procedural and long-term outcomes (to 3 years). The publication of their initial procedural and in-hospital experience in 2011 in 1,914 patients detailed an 82.9% overall procedural success rate and a reasonable rate of complications (2). A retrograde approach was used in 11.8% of all CTO cases. There was a lower success rate (64.5%; p < 0.05 vs. antegrade), more contrast use, and longer fluoroscopy times with a retrograde approach than with the antegrade approach, as well as a higher incidence of coronary artery perforation (although no difference in 30-day major adverse cardiovascular event rates was noted between the 2 approaches). At the same time the ERCTO results were published, the initial retrograde experience of 3 U.S. “dedicated” centers was reported (3). The procedural success rates (79.4%) as well as the rate of complications (2.6%) were strikingly similar to those of the Japanese experience, although in the U.S. experience, a substantial number of cases involved patients with prior coronary artery bypass grafting and PCI of CTOs performed for failed saphenous vein grafts.
In this issue of the Journal, the ERCTO group reports a follow-up of their initial PCI for CTO outcomes, detailing their retrograde CTO experience (4). The retrograde approach was used to treat 1,582 lesions in 1,395 patients. Over the 5-year study period, use of the retrograde approach increased from 11.8% in 2008 of all PCIs for CTOs to 25% in 2012. The overall success rate was 75.3%, substantially higher when the retrograde approach was chosen initially (82.2% success) rather than as a bailout for a failed antegrade approach (53.1% success). Procedural complications occurred in 6.8% of cases, driven principally by collateral channel perforation or hematoma and donor vessel thrombus or dissection, but the retrograde approach was associated with a very low overall in-hospital rate of major adverse cardiovascular and cerebrovascular events of 0.8%. Clinical follow-up was available in 66.7% of all patients, with a mean of 24.7 ± 15.0 months of follow-up. The overall rate of major adverse cardiovascular and cerebrovascular events was 13.6%, with a mortality rate of 1.9%, worse in those with failed procedures (4.3% vs. 0.6%; p < 0.001). Although the durability of CTO PCI has been questioned, the ERCTO experience indicates that clinical benefits of angina and dyspnea reduction persisted out to 3 years of follow-up, suggesting that the benefits are durable.
What should the general interventional cardiology community take away from these observations? Important issues to address in answering this broad question include whether these results are achievable by general interventionalists, whether these improved results will translate into meaningful clinical outcomes, and ultimately whether higher procedural success with lower complication rates will increase the propensity to choose or attempt PCI for a CTO (vs. coronary artery bypass grafting) within the general interventional community. With regard to the first issue, the results of the ERCTO study were achieved by operators whose skills and experience were acquired over a period of time, with commitment to a dedicated CTO practice. These operators also openly and frequently shared CTO successes and failures at national and international meetings and gatherings, quickly raising the level of knowledge surrounding important technical aspects of PCI for CTOs. The investigators show that minimal procedure experience was associated with lower procedural success, but the point of true competence in the learning curve for CTOs remains uncertain. Whether concerted efforts to provide specialized training for PCI for CTO will allow generalization of this procedure into mainstream interventional practices remains to be determined, but most signals indicate that there has been movement in this direction. Nonetheless, at least at this point in time, it appears that PCI for CTO will not be a mature skill set for fellows coming out of traditional 1-year training programs, nor for general interventional cardiologists, and will require additional post-graduate training to achieve.
Whether better PCI of CTO outcomes will result in meaningful improvements in patient outcomes remains to be determined. The reader is referred to a recent review in the Journal by Strauss et al. (5), who carefully and thoughtfully considered the concerns surrounding PCI for CTO as well as the evidence base supporting the potential benefits of complete revascularization (CR). In their aptly titled piece, “Revascularization of Chronic Total Occlusions: Time to Reconsider?” the investigators presented a cogent argument for wider adoption of CR, which in PCI terms means percutaneous treatment for CTOs. It must be acknowledged that the definitive evidence base for CR awaits the results of randomized clinical trials such as DECISION-CTO (Drug-Eluting Stent Implantation Versus Optimal Medical Treatment in Patients With Chronic Total Occlusion) and EURO-CTO (European Study on the Utilization of Revascularization Versus Optimal Medical Therapy for the Treatment of Chronic Total Coronary Occlusions). At least for now, better procedural success and outcomes such as those reported in ERCTO provide a stronger foundation to evaluate the impact of CR achieved by PCI for CTO on overall patient outcomes.
Finally, whether the observations of ERCTO will influence rank-and-file interventionalists’, or even general cardiologists’, propensity to choose or attempt PCI for a CTO as opposed to sending the patient for coronary artery bypass grafting remains to be determined. The issues are complex, and it may come down to a decision based on the potential impact of a CTO program on overall catheterization laboratory utilization. As noted above, procedure times are longer for CTO than non-CTO procedures, and lengthy procedures interrupt flow within the catheterization laboratory. Also, almost all experts advocate that 2 operators jointly perform PCI for a CTO. These 2 factors require programmatic commitment and resources for a CTO program, including dedicated catheterization laboratory time that goes well beyond that required of a non-CTO PCI program. Additionally, although ERCTO and other dedicated CTO operators have substantially reduced the complication rates associated with these procedures, ERCTO’s early retrograde experience was associated with a coronary perforation rate of almost 5%, requiring urgent pericardiocentesis in a large minority of patients. The counterarguments raised by many CTO experts are that improved techniques are being translated into lower complication rates, that their overall PCI skills are improved considerably, and that it is valuable to the entire revascularization program to be able to offer PCI for CTO to patients believed to have no options at non-CTO centers (6). While we await the results of randomized clinical trials, CTO experiences such as published here by ERCTO indicate that going backward may indeed mean going forward.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Applegate is a member of the advisory board of Abbott Vascular.
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