Impact of Coronary Artery Chronic Total Occlusion on Arrhythmic and Mortality Outcomes: A Systematic Review and Meta-Analysis.

OBJECTIVES: This study aimed to examine the relationship between chronic coronary artery total occlusion (CTO) status and the occurrence of ventricular tachycardia (VT)/ventricular fibrillation (VF) or appropriate implantable cardioverter-defibrillator (ICD) therapy.

BACKGROUND: CTO is a significant problem in patients with ischemic heart disease. However, the extent to which it predisposes affected individuals to VT/VF and whether these arrhythmic events could be prevented by revascularization are unclear. Therefore, a systematic review and meta-analysis were conducted to examine the relationship between CTO status and the occurrence of VT/VF or appropriate ICD therapy.

METHODS: PubMed and Embase databases were searched until November 16, 2017, identifying 137 studies.

RESULTS: Seventeen studies involving 54,594 subjects (mean age, 61 ± 21 years of age, 81% male) with a mean follow-up of 43 ± 31 months were included. The presence of CTO was associated with higher risk of VT/VF or appropriate ICD therapy (adjusted hazard ratio [aHR]: 1.99; 95% confidence interval (CI): 1.53 to 2.59; p < 0.0001, I2  = 3%) but not in cardiac mortality (aHR: 2.59; 95% CI: 0.64 to 10.59; p = 0.18, I2  = 86%) or in all-cause mortality (aHR: 1.70; 95% CI: 0.84 to 3.46; p = 0.14; I2  = 64%). Compared to patients with non-infarct-related CTOs, those with infarct-related CTOs have a higher risk of VT/VF or appropriate ICD therapy (aHR: 2.47; 95% CI: 1.76 to 3.46; p < 0.0001; I2  = 14%), cardiac mortality (aHR: 2.73; 95% CI: 1.02 to 7.30; p < 0.05; I2  = 79%) and higher all-cause mortality (aHR: 1.69; 95% CI: 1.19 to 2.40; p < 0.01; I2  = 40%). Nonrevascularization of CTOs tended to be associated with an increased risk of all-cause mortality compared to successful revascularization (unadjusted HR: 1.52; 95% CI: 0.96 to 2.43; p = 0.08; I2  = 76).

CONCLUSIONS: CTOs, especially infarct-related, are associated with high risk of VT/VF or appropriate ICD therapy and mortality. ICD implantation could be beneficial. However, it is not clear that revascularization has an impact on the outcome of patients with CTOs.