Background: The prevalence of success of percutaneous coronary interventions (PCIs) of chronic total occlusions (CTOs) remains relatively low. We determined the effect of preoperative multidetector computed tomography coronary angiography (CTCA) in PCIs of CTOs. Methods: The study population was 100 consecutive patients who underwent PCIs of CTOs from January 2005 to December 2007 at Keio University School of Medicine. They were divided into two groups according to the absence (non-CT group, n = 60) or presence (CT group, n = 40) of preoperative CTCA. The effect of preoperative CTCA was assessed in the prevalence of success of the procedure, prevalence of complications, irradiation time, and the dose of contrast agents. Results: The prevalence of procedural success was similar in both groups (non-CT group vs CT group 80.0% vs 77.5%, p = 0.76). Irradiation time and the dose of contrast agents were also similar between these groups. The prevalence of complications was significantly reduced in the CT group (23.3% vs 7.5%, p = 0.039), especially coronary perforations, which required treatment only in the non-CT group (10.0% vs 0.0%, p = 0.039). Multiple logistic regression analysis revealed that use of a rotablator (odds ratio [OR]: 4.40, 95% confidence interval [CI]: 1.19-16.27, p = 0.027) and absence of preoperative CTCA (OR: 4.26, 95% CI: 1.04-17.49, p = 0.044) were independent determinants of complications. Conclusion: Preoperative CTCA does not affect the prevalence of procedural success, irradiation time and the dose of contrast agents, but may be useful to reduce the prevalence of complications during PCIs of CTOs. (C) 2010 Elsevier Ireland Ltd. All rights reserved.