Prognostic Impact of Chronic Total Occlusions: A Report From SCAAR (Swedish Coronary Angiography and Angioplasty Registry)

Objectives The aim of this study was to determine the prognostic impact of chronic total occlusion (CTO) on long-term mortality in a large prospective cohort. Background CTO is present in many patients with coronary artery disease and is difficult to treat with percutaneous coronary intervention. Methods The study population consisted of all consecutive patients who underwent coronary angiography in Sweden between January 1, 2005 and January 1, 2012, who were registered in SCAAR (Swedish Coronary Angiography and Angioplasty Registry). The patient population was heterogeneous with regard to indication for angiography (stable angina, ST-segment elevation myocardial infarction [STEMI], unstable angina or non-STEMI, and other) and treatment options. The long-term mortality rates of patients with and without CTO were compared by using shared frailty Cox proportional hazards regression adjusted for confounders. Tests were conducted for interactions between CTO and several pre-specified characteristics: indication for angiography and percutaneous coronary intervention (stable angina, STEMI, unstable angina or non-STEMI, and other), severity of coronary artery disease (1-, 2-, and 3-vessel and/or left main coronary artery disease), age, sex, and diabetes. Results During the study period, 14,441 patients with CTO and 75,431 patients without CTO were registered in SCAAR. CTO was associated with higher mortality (hazard ratio: 1.29; 95% confidence interval: 1.22 to 1.37; p < 0.001). In subgroup analyses, the risk attributable to CTO was lowest in patients with stable angina and highest in those with STEMI. In addition, CTO was associated with highest risk in patients under 60 years of age and with lowest risk in octogenarians. There was no interaction between CTO and either diabetes or sex, suggesting an equally adverse effect in both groups. Conclusions In this large prospective observational study of patients with coronary artery disease, CTO was associated with increased mortality. This association was most prominent in younger patients and in those with acute coronary syndromes.