Several studies have shown favorable or unfavorable effects of dissection following drug-coated balloon (DCB) angioplasty. However, there is no established method to precisely assess the dissection during DCB treatment, and the relationship between the dissection and late lumen gain (LLG) remains unclear.

The present study consisted of patients enrolled in the TRANSFORM-I trial, which is a randomized trial comparing novel Magic TouchTM sirolimus coated-balloon with SeQuent Please NeoTM paclitaxel-coated balloon in patients with de-novo small vessel coronary artery diseases.100 lesions in 98 patients were investigated with OCT after pre-dilatation to assess the dissection. A customized software (QCU-CMS, Leiden) precisely quantifies the dissection and lumen volumes separated by a common boundary connecting the two edges of the intimal fracture (Figure). Quantitative OCT analysis of dissection volume is derived from cross-sectional slices with a thickness of 200 microns using the Simpsons rule.The tissue composition analysis, using OctPlus software (Pulse, Shanghai) and QCU-CMS, at the starting site of the dissection was performed to elucidate the mechanisms triggering the dissection. Finally, the relationship between the quantified dissection volume and late lumen loss (LLL) or LLG at 6-month angiography was investigated.

The dissection was found in 96% (96/100) of the treated lesions. The median dissection volume was 1.98 mm3. The median maximal dissection arc was 113 degrees. The tissue composition analysis showed that the dissection occurs at the thinnest site (320 μm) of fibrous intima (83%).

Dissection occurs frequently during DCB treatment and we developed a new method to quantify the dissection precisely. Final results with 6-month outcome, the relationship between the dissection and LLL/LLG, will be presented at the time of congress.