Risks, Benefits of CTO PCI Must be Weighed
New data from the DECISION-CTO trial, presented at the American College of Cardiology Scientific Session in March, have fueled the ongoing controversy about the risks and benefits of chronic total occlusion PCI.
Among 834 patients — most of whom had multivessel disease in addition to the CTO — CTO PCI did not result in improved symptoms or reduction in death, MI or coronary revascularization. CTO PCI was, however, successful in 91% of cases.
Interpretation of the DECISION-CTO trial results is challenging due to limitations of the design and conduct. For example, there were few symptoms at baseline, uncertainty about the presence and extent of ischemia and an 18% crossover rate from the medical therapy group to CTO PCI. In addition, the study was discontinued prematurely because of slow enrollment.
DECISION-CTO is only the second randomized controlled trial in this setting published to date. The first trial, EXPLORE, showed no difference in ejection fraction after 4 months between patients with acute STEMI who underwent CTO PCI vs. those who did not undergo CTO PCI. This study, however, was also limited by relatively low success rates (73%) and uncertainty about the viability of the myocardium supplied by the occluded artery.
The DECISION-CTO and EXPLORE trials appropriately bring attention to the important question of which patients should be offered CTO PCI. Is CTO PCI a futile procedure? Should revascularization only be offered for subtotal coronary occlusions?
Here is my answer: CTO PCI should be offered to patients when the anticipated benefits exceed the potential risks.
Benefits of CTO PCI
The main benefit of CTO PCI is symptom improvement, as is true for most PCIs performed in patients with stable CAD. Patients with coronary CTOs often have angina and/or dyspnea refractory to medical therapy that impairs their quality of life and limits their activities. Many such patients have multivessel CAD and often undergo CABG surgery. Many others are either poor candidates for CABG (eg, patients with prior CABG) or surgery is not appropriate (eg,patients with a single-vessel right coronary artery CTO).
To date, there is no randomized controlled trial of CTO PCI vs. medical therapy using sham control. One such study — SHINE-CTO — is ongoing. However, observational studies and personal experience have shown that CTO PCI works: It makes patients feel better, and the benefit is more pronounced in patients with more severe baseline symptoms.
Does that mean that CTO PCI has no role in stable patients who do not have severe symptoms, but have ischemia or left ventricular dysfunction? Although we do not know for sure, the burden of proof is higher in this area. It is possible that patients with large area of ischemia or extensive, reversible LV dysfunction could derive benefit from CTO PCI (or CABG if indicated and feasible), but it is unlikely that the large studies required to prove it will ever be performed.
For any benefit to be realized, the CTO must be recanalized. This is self-evident; therefore, the likelihood of success has implications about whether CTO PCI should be offered in the first place. CTO PCI would be more appropriate to offer at centers that achieve 85% to 90% success rates as compared with centers that have 59% success rates, which is the average success rate for CTO PCI in ACC’s National Cardiovascular Data Registry between 2009 and 2013.
Several scores have been developed to predict the likelihood of CTO PCI success, but each score applies to the centers and operators from which it was developed and may be hard to extrapolate in other settings.
Risks of CTO PCI
CTO PCI carries risk for complications. CTO PCI can lead to perforation and tamponade, donor vessel injury, emergency bypass graft surgery, MI and death. Even if the procedure is successfully completed, complications such as radiation skin injury, restenosis and stent thrombosis can still occur months or even years after CTO PCI.
The risk is higher than that of non-CTO PCI, especially when the retrograde approach is used for recanalization. A CTO PCI risk score was recently developed (PROGRESS CTO complications score) that provides a numeric estimate of risk based on three key parameters:
- age of the patients: older age = higher risk;
- lesion length: 23 mm = higher risk; and
- use of the retrograde approach.
Benefit vs. Risk
In a 50-year-old patient with single-vessel CTO and severe ischemic symptoms that cannot be controlled with medications, CTO PCI should, in general, be offered, as there is much to be gained.
In contrast, in a 90-year-old patient with fatigue and a CTO, medical therapy alone is in most cases the preferred course of action.
Like every other decision in medicine, a frank and in-depth discussion about the risks and benefits and goals and alternatives of CTO PCI is recommended to make the best possible decision.
The Present and Future
Despite the results of the EXPLORE and DECISION-CTO trials, CTO PCI remains an important treatment option for many patients with advanced CAD. Clearly, many, if not most, CTOs do not need to be recanalized. Many other CTOs, however, cause severe symptoms and, if recanalized, the patients’ quality of life will be significantly improved.
There is no question that more research is needed to better understand the benefits and risks of CTO PCI. There are several ongoing studies, and many others being planned.
Would you tell a patient who cannot walk due to hip pain that hip-replacement surgery is not indicated because hip replacement has not been shown to improve hip pain in randomized controlled trials? Similarly, should you tell a patient with a CTO causing severe refractory angina who is not a candidate for surgery that he or she does not have any other treatment options? Or should you discuss with the patient the option of CTO PCI with all its strengths and limitations? The latter course of action would probably be in the best interest of the patient. Which is what matters the most.
- Henriques JP, et al. J Am Coll Cardiol. 2016;doi:10.1016/j.jacc.2016.07.744.
- Park SJ, et al. Late-Breaking Clinical Trials: Interventional. Presented at: American College of Cardiology Scientific Session; March 17-19, 2017; Washington, D.C.
- PROGRESS-CTO CTO Risk Calculator. Available at: www.progresscto.org/cto-scores. Accessed April 3, 2017.
- The SHINE-CTO trial. ClinicalTrials.gov. Available at: clinicaltrials.gov/ct2/show/NCT02784418?term=NCT02784418&rank=1. Accessed April 3, 2017.
- For more information:
- Emmanouil S. Brilakis, MD, PhD, is from Minneapolis Heart Institute in Minneapolis, Minnesota, and VA North Texas Health Care System and University of Texas Southwestern Medical Center. He is a member of the Cardiology Today’s Intervention Editorial Board. Brilakis can be reached at 920 E. 28th St. #300, Minneapolis, MN 55407; email: firstname.lastname@example.org.
Disclosure: Brilakis reports receiving consultant and speaker honoraria from Abbott Vascular, Asahi, Cardinal Health, Elsevier, GE Healthcare and St. Jude Medical; research support from Boston Scientific and InfraRedx; and his spouse is an employee of Medtronic.