Aims

In this study we investigated the outcome of Bioengineered Combo Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Coronary Stent in Patients with chronic total occlusion evaluated by clinical outcome and Optical Coherence Tomography Imaging Analysis

Methods and results

The study was prospectively conducted from september 2018 to march 2019. Data from 39 eligible patients (≥18 years) who had successfully undergone OCT-guided revascularization of a CTO at the University Medical Center Mainz and were treated with Combo® DTS were analysed. Clinical assessment, angiography (with Quantitative Coronary Analysis) and OCT examination was performed at baseline and at follow-up. The clinical follow-up was performed 6 months after stent implantation as part of routine clinical care. Patients with a re-stenosis in the first follow-up were re-examined after 6 months.

Thirty nine patients were included in the study and treated with Combo® DTS after successful revascularisation of a CTO. Follow-up data of 34 patients was available. The median follow up period was 189 days ranging from 157 to 615 days. During this period, coronary angiography was performed to investigate the result after CTO recanalization. We investigated a complex study population with a high J-CTO Score (2.5± 0.5) and a high rate of multivessel coronary vessel disease. Stent implantation was controlled by OCT imaging.

At follow-up in 35.9% (14 of 39) patients with angiographic restenosis (diameter stenosis > 50% by visual estimation at follow-up angiography, confirmed by QCA) revascularization was required. Eleven patients (76.9%) with in-stent restenosis were treated with drug eluting balloon, three (23.1%) with implantation of a drug eluting stent (DES). The overall major adverse clinical event rate was 7.7% (3/35). One patient died of cancer, another was treated with coronary bypass surgery due to rapid progression of coronary heart disease and one patient presented with acute heart failure due to left main disease after 615 days.

None of the clinical and procedural characteristics was associated with the incidence of restenosis at six months.  

Neointima proliferation was detected in 23 (59%) patients, 14 (35.9%) showed homogenous and 9 (23.1%) heterogenous neointima. Neointima formation was often associated with microvessels (17/35). Neoatheroslcerosis was observed in 2 (5.1%) patients. Malapposition was found in 4 (10.3%) of the patients and stent fractures in 11 (28.1%). Only in one patient with a stentfracture type IV a stent thrombosis was detected. Rate of strut coverage was 96.1% at follow-up. 

Conclusion

The implantation of a Combo® DTS after successful CTO recanalization was associated with a restenosis rate as high as 35.9%  despite good stent implantation at baseline proven by OCT. Neointima formation was found as a main cause of restenosis. Nevertheless, we observed a low rate of major cardiovascular events in our follow-up.