Impact of Calcium Cracks after Balloon Angioplasty in Patients with Complex Calcified Coronary Plaque The Results of the OCT-CALC Registry

Background: Target lesion calcification is known to influence the percutaneous coronary intervention (PCI) outcomes. This study aimed to assess the impact of calcium cracks after balloon angioplasty on the PCI results as well as the long-term clinical outcomes by multicenter optical coherence tomography (OCT)-guided PCI registry. Methods: We formed a prospective, multicenter registry that include 22 sites from Japan and Korea that enrolled 268 patients who underwent PCI to the lesion with moderate to severe calcification on angiogram. Balloon dilatation and subsequent drug elution stent (DES) implantation were performed with OCT guidance in every case. Serial OCT images just before and after balloon angioplasty, and after stent implantation were analyzed at 1-mm intervals by an independent core laboratory. By protocol, follow-up angiography was performed 10 months after PCI (in 85.5% of patients), and both baseline and follow-up angiograms were analyzed by an angiographic core laboratory. The primary endpoint was the relationship between calcium crack after balloon angioplasty and stent expansion. The secondary endpoint was target vessel failure (TVF) at 1 year, defined as a composite of cardiac death, target vessel-related myocardial infarction, and target vessel revascularization. Results: A total of 242 patients were analyzed. Of these, OCT analysis was performed in 147 patients with a complete OCT data set. Calcium cracks were observed in 28 patients (19%) at the minimal lumen area (MLA) site. The percent stent expansion was greater in lesions with calcium crack than those without (99±26 % vs. 91±18 %, p=0.039). In 229 patients who underwent clinical follow-up at 1 year, TVF occurred in 23 patients (10.0%). In 139 patients in whom both OCT analysis and 1-year clinical follow-up was performed, the incidence of TVF was similar between patients with and without crack formation (11 % vs. 13 %, p=1.00). Angiographic sub-analysis with both baseline and 10-months follow-up was performed in 124 patients. Acute lumen gain, as well as late lumens loss, were greater in patients with calcium crack than those without (1.39±0.55 mm vs. 1.15±0.48 mm, p=0.037; 0.51±0.67 mm vs. 0.12±0.51 mm, p=0.0095, respectively), resulting in similar net lumen gains between the 2 groups. Conclusion: The OCT-guided PCI strategy demonstrated acceptable acute and 1-year clinical outcomes. The presence of calcium cracks after balloon angioplasty may have a potential impact on acute results after DES implantation in calcified lesions. However, its impact may be attenuated by late lumen loss at 10-months follow-up. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial UMIN 000018636 ### Funding Statement This study was funded by Daiichi Sankyo CO., Ltd. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: IRB of Yokohama City University Medical Center gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Raw data were generated at Yokohama City University Medical Center. Derived data supporting the findings of this study are available from the corresponding author on request.