Illusion of coronary artery chronic total occlusion-associated ventricular arrhythmia: results from a multi-centre study

Abstract

Abstract Background/Introduction Coronary artery chronic total occlusion (CTO) is frequently encountered in patients with established coronary artery disease (CAD) with a reported incidence of more than thirty percent in this population (1). A previous large single-centre study established CTO as an independent risk factor for occurrence of ventricular arrhythmia in patients with ICD and ischemic heart disease (2). The significance of CTO in all-comers has not been investigated. In this large retrospective data, it was analysed that there is no significant difference in ventricular arrhythmia occurrence in patients with CTO versus those with CAD and no CTO. Purpose The purpose of this study is to examine the association between CTO and ventricular arrhythmia in patients with CAD using a pooled de-identified database. Methods This retrospective observational study used IBM Explorys, which is a pooled de-identified multi-institutional database of more than 60 million unique patients in the United States. A search was done to identify patients with CTO and those with CAD with the exclusion of CTO diagnosis. The data were analysed for ventricular tachycardia (VT) and/or ventricular fibrillation (VF) occurrence. The data were stratified by presence of systolic HF to identify possible effect modification. Statistical analysis was performed by calculating odds ratios (OR) with associated confidence intervals. Results Among the 190 patients with the diagnosis of CTO, 11.8% had VT/VF. Of the 2,796,600 patients with CAD and no CTO, 6.9% had VT/VF. The diagnosis of CTO was associated with an increased risk for VT/VF with OR 1.7143 (1.0786, 2.7247), p<0.05. Upon stratification by presence or absence of systolic HF, there was no statistically significant difference in occurrence of VT/VF in the two strata. In the systolic HF group, the OR was 1.4331 (0.6708, 3.0619), p=0.47; the no systolic HF group had OR 0.9717 (0.5123, 1.843), p=0.92. In patients with CAD, the diagnosis of systolic HF was associated with an increased risk of CTO with OR 2.5616 (1.7268, 3.7999), p<0.05. Conclusion Stratification by presence or absence of systolic HF yielded inconsistent and statistically insignificant odds ratios compared to the all-comers group, suggesting effect modification by HF with no statistically significant association between CTO and VT/VF. These findings from this large multicentre retrospective data suggest that CTO itself is not an independent risk factor for ventricular arrhythmia in patients with CAD. Limitations of this study include that it is a retrospective pooled analysis without individualised data on ejection fraction and the inability to distinguish if the CTO was infarct-related. Further prospective studies are needed to evaluate the significance of CTO in patients with CAD as it pertains to ventricular arrhythmia. Funding Acknowledgement Type of funding sources: None.