COMBO Stent Achieves Neointimal Regression at 24 Months

A dual-therapy stent achieved favorable outcomes of neointimal suppression, including 24-month regression observed for the first time in a drug-eluting stent (DES), according to findings presented at TCT 2014.

In the EGO-COMBO study, researchers tested the COMBO Dual Therapy Stent (OrbusNeich Medical), which combines abluminal sirolimus drug elution with an antibody surface that captures endothelial progenitor cells to the device, forming an endothelial layer to combat thrombosis and restenosis. Stephen W.L. Lee, MD, of Queen Mary Hospital, University of Hong Kong, China, presented results of 61 patients with 74 lesions treated with 88 COMBO stents including 24-month optical coherence tomography (OCT) results and 36-month clinical outcomes. Mean patient age was 62.2 years, 77% were men and 32.8% had diabetes.

Encouraging healing, clinical outcomes 

OCT documented that the patients receiving the COMBO stent achieved neointimal regression from 9 months to 24 months. A reduction of in-stent percentage neointimal volume, which Lee said is “the most important surrogate marker for neointima assessment,” was statistically significant over that time frame (see Figure).

Median strut-level neointimal thickness also was reduced in patients from 9 months (0.14 mm; interquartile range [IQR] 0.08-0.21 mm) to 24 months (0.12 mm; IQR 0.07-0.19 mm; P<.001).

Reductions were also observed in median neointimal cross section area at 1 mm sampling from 1.34 mm² (IQR 1.02-1.65 mm²) to 1.16 mm2 (IQR 0.92-1.52 mm²; P=.001) and neointimal volume from 29.91 mm³ (IQR 22.13-43.22 mm³) to 26.17 mm³ (IQR 19.64-35.81 mm³; P=.003).

The researchers observed no MI, neoatherosclerosis or definite or probable late-stent thrombosis, Lee said. At 36 months, they observed only one case (1.64%) of target lesion revascularization  (TLR) or target vessel failure; that patient died from vessel failure at 22 months after experiencing chest pain and not seeking medical advice, he said. The overall MACE rate beyond 36 months was 3.3%.

Lee and colleagues also documented via OCT the progression of strut coverage and found that 100% coverage was achieved at approximately 5 months. “We are quite certain that 5-month [dual antiplatelet therapy] will be long enough for this group of patients,” he said.

Rapid strut coverage in the early phase could represent optimal stent healing and predict better clinical outcomes and fewer late stent failure events, Lee suggested. “In most DES, when the patient dies, we will discover uncovered struts.”

Angiographic results at 9 months included a median in-stent late lumen loss of 0.24 mm (IQR 0.08-0.40 mm).

Long-term issues with monotherapy DES

Lee noted that, conversely, monotherapy DES have been associated with a continuous increase in restenosis and TLR over time. While these DES achieve adequate short-term neointimal suppression, “they all have a course of prolonged DAPT, and they all have accelerated neoatherosclerosis and late stent failure, late loss catch-up and late stent thrombosis,” he said.

Disclosures:  

• The study was supported by OrbusNeich.

• Lee reports no relevant conflicts of interest.