Author + information
- Mohammad Reza Movahed, MD, PhD⁎ ()
- ↵⁎Department of Medicine, Division of Cardiology, Southern Arizona Veterans Affairs Health Care System, Cardiology (1-111C), 3601 South Sixth Avenue, Tucson, Arizona 85723
In the paper by Mehran et al. (1), the authors concluded that failure to open chronic total occlusion (CTO) lesions leads to a higher rate of cardiac death, total death, and coronary artery bypass surgery (CABG). The authors explain their findings on the basis of the possible deleterious effects of a persistently closed artery leading to more adverse events. However, the authors did not comment on the procedural complications, such as perforations, that could have occurred during a long, complicated CTO procedure, such as renal failure, bleeding, or peripheral vascular injury. In this registry, patients with unsuccessful CTO percutaneous coronary intervention had a high rate of procedural-related coronary perforation (7.4% vs. 1.7% in the successfully treated arm). The authors did not mention the rate of death or urgent CABG occurring among those with coronary perforation and whether this might explain the higher frequency of CABG, mortality, and myocardial infarction occurring in the unsuccessful CTO intervention cohort.
Let us compare this study to a hypothetical randomized clinical trial where any complication (including death or perforation) would be assigned to the treatment group independent of successful delivery of the treatment (i.e., an intention-to-treat analysis). Applying this rule to the current study and transferring the perforation rate of 7.5% in the unsuccessful CTO intervention arm (higher than the 5.8% cardiac mortality in the failed CTO arm after 5 years) to the arm with successful CTO intervention would clearly show that overall CTO intervention led to a relatively poor outcome. Therefore, their conclusion should have been that intervention of CTO lesions would have been harmful due to the very high procedural complication rate, offsetting any potential benefit. Multivariate analysis adjusting for perforation would be invalid, because perforation was related to intervention and not due to a permanently occluded artery that was blamed for the poor long-term outcome. Other important percutaneous coronary intervention-related complications, such as contrast-induced nephropathy and bleeding, were not mentioned. Lee et al. (2) published their experience with regard to unsuccessful CTO intervention in the same month that this current report was published. In the Lee et al. (2) paper, they showed no difference in any outcomes between successful or unsuccessful CTO intervention, despite worse baseline characteristics of patients undergoing unsuccessful CTO attempt, thereby somewhat contradicting the current paper.
- American College of Cardiology Foundation
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- Lee S.W.,
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