Modified contrast microinjection technique to facilitate chronic total occlusion recanalization

Objectives To assess the efficacy and safety of the modified contrast microinjection technique to facilitate chronic total occlusion recanalization. Background The success rate of chronic total occlusion percutaneous coronary intervention (CTO-PCI) does not exceed 90% even in the most experienced centres. We have previously demonstrated that a large volume of contrast injected into the subintimal space can facilitate recanalization but is limited by a risk of serious complication. The aim of this study was to assess the application, efficacy and safety of a modified contrast microinjection technique that utilizes the injection of a much smaller volume of contrast in CTO-PCI. Methods A retrospective analysis of patients in whom the modified microinjection technique was utilised in patients undergoing CTO-PCI at five tertiary centres was conducted. Results: Of 1,192 patients who underwent CTO-PCI, the microinjection technique was used in 59 patients (4.7%). The majority of CTOs treated were in the right coronary artery (79.7%), were of high complexity and 35.6% of lesions had a least one previously failed PCI attempt. The modified microinjection technique was used for more than one indication in 7 (11.9%) of patients. The success rate was 81.4%. There were no procedural complications related to the use of the reported modified microinjection. Conclusion Initial experience with the modified microinjection demonstrates that it can be performed safely, is reproducible, and is broadly applicable. Whilst not required for all CTO procedures it can be a helpful adjunctive tool to increase the likelihood of success especially in complex, or refractory cases, without compromising the safety of the procedure.