Very early tissue coverage after drug-eluting stent implantation: an optical coherence tomography study

Very short-term tissue coverage of the CD34 antibody-covered sirolimus-eluting stent: an optical coherence tomography study

It is well known that patients with acute myocardial infarction (AMI) have delayed vessel healing despite accelerated endothelial progenitor cells (EPC) mobilization. The COMBO stent is a unique biodegradable-polymer sirolimus-eluting stent with an anti-CD34 antibody coating which captures EPC and potentially promotes vessel healing. However, there are limited data about strut tissue coverage at the very short-term period after COMBO stent implantation. This was a prospective study to investigate strut tissue coverage within 1 month after COMBO stent implantation using optical coherence tomography (OCT). Struts fully covered with tissue were defined as covered, and struts with distance from lumen surface longer than strut plus polymer thickness were defined as malapposed. Mean tissue thickness was measured only in apposed struts. A total of 8173 struts of 33 lesions in 32 patients were analyzed at an average of 19.8 ± 4.6 days after COMBO stent implantation. In lesion-level analysis, the rate of covered struts was 89.6 ± 7.2%, the rate of malapposed struts was 0.9 ± 2.0% and mean tissue thickness was 46.8 ± 14.3 µm. In comparison between AMI (n = 12) and non-AMI (n = 21) patients, there were no significant differences in the rate of covered struts (88.4 ± 8.4% vs. 90.2 ± 6.6%, p = 0.48) and mean tissue thickness (46.8 ± 13.7 µm vs. 46.9 ± 15.0 µm, p = 0.98). Multivariable analysis demonstrated that time from implantation to OCT imaging was significantly associated with mean tissue thickness. The COMBO stent had substantial tissue coverage at the very short-term period after implantation even in AMI patients, and follow-up time had an impact on vessel healing.

Preliminary studies on intimal injury related to stent retrieval in a canine model

OBJECTIVE

This pilot study aimed to observe intimal injuries related to stent retrieval in the iliac artery of a canine.

BACKGROUND

In-stent restenosis remains challenging owing to permanent stent implantation. A retrievable stent may be alternative for intervention without permanent residue.

METHODS

Five retrievable stents with point-to-point overlapped double-layer scaffolds were deployed into the iliac arteries and retrieved on days 14, 21, 28, 35, and 42 from five canines.

RESULTS

Arterial diameter decreased by 9-10% before retrieval and 15% on day 14 after retrieval. In the 14-day-stent, the stent surface was clean without visible fibrin. In the 28-day-stent, the overlay was mainly composed of fibrin and fibroblasts. The proliferation of smooth muscle cells has not yet been observed with α-smooth muscle actin staining. In the 42-day-stent, endothelial and smooth muscle cells decreased under the struts, and the internal elastic lamina was interrupted segmentally. Neointima formation involves fibroblasts and smooth muscle cells. Neointimal thickness was negatively correlated with strut space. Stent traces on the artery wall tended to be flat at a follow-up14 days after retrieval. The primary intima was completely covered by neointima. Two stents could not be retrieved because of in-stent thrombosis or capture loss.

CONCLUSIONS

The stent was covered mainly by depositional fibrin after 28 days and by typical neointima after 42 days. The stent retrieval procedure did not induce injury to vascular smooth muscle, and the intima repair was performed 14 days after stent retrieval.

Angioscopic findings 1 year after percutaneous coronary intervention for chronic total occlusion

BACKGROUND

Chronic total occlusion (CTO) is a high-risk factor for stent thrombosis, but little is known about the difference in neointimal healing between CTO and non-CTO lesions regarding implanted stents. We investigated factors affecting neointimal healing after stent implantation for CTO and non-CTO lesions using angioscopy.

METHODS

We retrospectively evaluated 106 stents in 85 consecutive patients between March 2016 and July 2020. Their average age was 68 ± 11 years, and participants (73 male and 12 female) underwent follow-up angiography and angioscopy 1 year after percutaneous coronary intervention (PCI). The stents (n = 106) were divided into three groups according to the lesion status at the previous PCI: CTO (n = 17), acute coronary syndrome (ACS) (n = 35), and stable coronary artery disease without CTO or non-CTO (n = 54).

RESULTS

The neointimal stent coverage grade was significantly lower in the CTO and ACS groups than in the non-CTO group (0.4 ± 0.5, 0.9 ± 0.8, and 1.4 ± 0.8, respectively, p < 0.001). Thrombi were significantly more frequent in CTO and ACS than in non-CTO (71 %, 51 %, and 15 %, respectively, p < 0.001). The yellow grade in CTO was comparable to that in ACS but significantly higher in CTO than in non-CTO (CTO vs. ACS vs. non-CTO 1.5 ± 0.7, 1.4 ± 0.6, and 0.9 ± 0.7, respectively, p = 0.007).

CONCLUSIONS

Delayed healing occurs in stents implanted for CTO lesions. Longer dual-antithrombotic therapy may be beneficial.

Overlapping Drug-Eluting Stent Is Associated with Increased Definite Stent Thrombosis and Revascularization: Results from 15,561 Patients in the AUTHENTIC Study

PURPOSE

This study was to analyze the incidence of definite stent thrombosis (ST) after the implantation of drug-eluting stents (DESs) and cutoff value of overlapping length for predicting definite ST. An overlapping stent is associated with a high rate of clinical events after DES implantation compared with a non-overlapping stent. However, the rates of definite ST and clinical outcomes from a large patient population remain underreported.

METHODS

A total of 15,561 patients with 24,183 lesions who underwent DES implantation from January 2005 to February 2017 were retrospectively included in 5 tertiary hospitals in China. The main endpoint was the incidence of definite ST after procedures.

RESULTS

With a median of 1932 (IQR = 1194-2929) days, clinical follow-up was available in 7484 patients in the overlap group and in 8077 patients in the non-overlap group. The rates of definite ST were 3.1% in the overlap group and 1.2% in the non-overlap group (HR: 2.67 (95% CI: 2.11-3.38), p < 0.001). Of the 24,183 treated lesions, the incidences of definite ST were 2.4% in the overlap group and 0.9% in the non-overlap group (HR: 2.96 (95% CI: 2.38-3.69), p < 0.001). Stent overlap was associated with a higher rate of target lesion revascularization (TLR) (9.4%) compared with stent non-overlap (6.4%, p < 0.001). The length of overlapping stent ≥ 2.93 mm strongly correlated with definite ST.

CONCLUSION

The present study shows that overlapping DES increases definite ST and revascularization in patients during long-term follow-up. In addition, the longer overlapping zone was associated with worse clinical outcomes.

Supporting evidence from optical coherence tomography for shortening dual antiplatelet therapy after drug-eluting stents implantation

INTRODUCTION

Dual antiplatelet therapy (DAPT) is required for coronary artery disease treated with drug-eluting stents (DES) implantation. Shortening DAPT duration would be beneficial for patients with high bleeding risk.

AREAS COVERED

Early healing patterns, especially stent strut coverage, assessed by optical coherence tomography (OCT) as a surrogate of neointima have been investigated to make decisions on whether short DAPT would be a safe alternative. This review evaluates the OCT evidence (i.e. neointimal coverage of stent struts within 3 months) for shortening DAPT duration after DES implantation.

EXPERT COMMENTARY

Shortening DAPT (i.e. within 3 months) duration after DES implantation might reduce complications including bleeding without increasing stent thrombosis. However, the optimal duration of DAPT after DES implantation is under discussion. Long-term assessment of short DAPT is required for the decision of the new guidelines regarding the recommended duration of DAPT.