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Management of coronary chronic total occlusion

December 1, 2017|Cleveland Clinic Journal of Medicine
Jaikirshan Khatri, MD;Mouin Abdallah, MD;Stephen Ellis, MD
Author and Disclosure Information

Jaikirshan Khatri, MD
Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic

Mouin Abdallah, MD
Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic

Stephen Ellis, MD
Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic

Correspondence: Jaikirshan Khatri, MD, Department of Cardiovascular Medicine, Heart and Vascular Institute, J3-5, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; khatrij@ccf.org

Drs. Khatri and Abdallah reported no financial interests or relationships that pose a potential conflict of interest with this article. Dr. Ellis reported research grant support from Abbott Vascular and consulting/advisory fees from Abbott Vascular, Boston Scientific, and Medtronic.

ABSTRACT

Percutaneous coronary intervention (PCI) for coronary artery chronic total occlusion (CTO) is an important treatment to be used in conjunction with non-CTO PCI, coronary artery bypass grafting, and optimal medical therapy to achieve complete revascularization in patients with coronary artery disease.

KEY POINTS

  • Coronary CTO is not benign and is associated with ischemic burden.
  • There is a threshold of ischemic burden at which revascularization is superior to optimal medical therapy.
  • Revascularization based on physiology rather than angiography can produce superior clinical results.
  • CTO PCI procedures are technically demanding and heavily operator-dependent in order to achieve high success rates at an acceptably low complication rate.

CLINICAL BENEFITS OF CTO PCI

In patients with significant ischemic burden, CTO PCI has multiple clinical benefits. Symptomatic relief based on the Seattle Angina Questionnaire appears to be similar to that obtained with coronary artery bypass grafting (CABG) at 1-month follow up.15 Successful CTO PCI can have a positive impact on the risk of mortality in prospective13 and retrospective observational studies.16

CTO intervention may also have beneficial effects on left ventricular systolic function in patients with viable myocardium in the corresponding coronary territory.17 This improvement in systolic function appears to be sustained at 3 years of follow-up.18 Meta-analysis of observational data in symptomatic and ischemic patients who underwent successful CTO PCI shows reduced rates of all-cause mortality and MACE and a reduced need for subsequent CABG.19 This is in contrast to the frequently cited Occluded Artery Trial (OAT) trial, which showed no clinical benefit of PCI for a subacutely occluded infarct-related artery.20

Figure 2. An algorithmic approach to determining the need for and the method of coronary revascularization in patients with coronary chronic total occlusion (CTO). Coronary artery bypass grafting (CABG) is preferable to percutaneous coronary intervention (PCI) in patients with complex or multivessel disease, whereas PCI is a reasonable option in patients with anatomically simple or single-vessel disease. Deciding on the appropriate treatment requires consultation with a surgeon and an interventionalist experienced in CTO PCI. Dual-injection angiography may be required to determine the technical feasibility of CTO PCI.
An algorithimic approach to assessing the need for and the method of coronary revascularization is provided in Figure 2.

EVIDENCE-BASED BENEFITS

Evidence of the merits of CTO PCI from randomized clinical trials is mixed. The only published study to date, the Evaluating Xience and Left Ventricular Function in Percutaneous Coronary Intervention on Occlusions After ST-Segment Elevation (EXPLORE) trial, showed no difference in left ventricular systolic function 4 months after ST-elevation myocardial infarction in patients undergoing staged CTO PCI of a non-infarct-related artery vs optimal medical therapy.21 Two larger trials presented at scientific meetings in 2017 remain unpublished. One trial showed noninferiority of optimal medical therapy vs successful CTO PCI in reducing the composite end point of all-cause mortality, myocardial infarction, stroke, and repeat revascularization; the other trial showed significant improvement in quality of life measures using the Seattle Angina Questionnaire score and Canadian Cardiovascular Society angina classification in patients who underwent successful CTO PCI compared with medical management.

High-volume CTO PCI centers now report procedural success rates as high as 92.9%22 and a correlation between the CTO PCI volume and CTO PCI success rates.3 The dramatic improvement in success rates achieved by high-volume operators globally can be attributed to a combination of operator experience, improved technology, and widespread adoption of the hybrid algorithm, which has helped to improve efficiency and standardize treatment in CTO PCI based on angiographic criteria.23 CTO PCI remains a highly specialized procedure, unique from patent-vessel PCI and with little correlation between total PCI volume and CTO PCI success rate. Despite recent advances, CTO PCI success remains heavily dependent on operator expertises, with a steep and long learning curve. In addition, the unique technical aspects of CTO PCI such as a retrograde and subintimal guidewire tracking that have accelerated procedural success are associated with higher rates of MACE compared with traditional antegrade and intraluminal guidewire tracking.24,25 Therefore, CTO PCI requires unique considerations beyond standard PCI in terms of potential complications. Uncommon but potentially life-threatening complications such as donor artery thrombosis, collateral vessel trauma, gear entrapment, and radiation skin injury demand a specialized informed consent process for the patient.26

In light of incomplete evidence based on extensive observational data and limited randomized clinical trials, the decision to refer patients for CTO PCI requires a comprehensive clinical evaluation. We know from data derived from patients with patent but stenotic coronary arteries that physiologically rather than angiographically driven decisions to revascularize can produce superior clinical results. There is an ischemic burden threshold beyond which revascularization is superior to optimal medical therapy. In this context, we know that CTO is not benign and is associated with ischemic burden. Consequently, patients with symptoms related to CTO represent a subset of patients with incomplete revascularization.

CONCLUSION

Despite recent advances, CTO PCI procedures remain technically demanding, and success with a low complication rate is heavily dependent on operator expertise. Therefore, CTO PCI should be used judiciously in patients with angina refractory to optimal medical therapy. It is an important tool to be used in conjunction with non-CTO PCI, CABG, and optimal medical therapy to produce favorable outcomes in patients with CAD.

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