Angioscopic and optical coherence tomographic evaluation of neointimal coverage: 9 months after expandable polyterafluoroethylene covered stent implantation

Biaxial stretching of polytetrafluoroethylene in industrial scale to fabricate medical ePTFE membrane with node-fibril microstructure

Expanded polytetrafluoroethylene (ePTFE) is promising in biomedical fields such as covered stents and plastic surgery owing to its excellent biocompatibility and mechanical properties. However, ePTFE material prepared by the traditional biaxial stretching process is with thicker middle and thinner sides due to the bowing effect, which poses a major problem in industrial-scale fabrication. To solve this problem, we design an olive-shaped winding roller to provide the middle part of the ePTFE tape with a greater longitudinal stretching amplitude than the two sides, so as to make up for the excessive longitudinal retraction tendency of the middle part when it is transversely stretched. The as-fabricated ePTFE membrane has, as designed, uniform thickness and node-fibril microstructure. In addition, we examine the effects of mass ratio of lubricant to PTFE powder, biaxial stretching ratio and sintering temperature on the performance of the resultant ePTFE membranes. Particularly, the relation between the internal microstructure of the ePTFE membrane and its mechanical properties is revealed. Besides stable mechanical properties, the sintered ePTFE membrane exhibits satisfactory biological properties. We make a series of biological assessments including in vitro hemolysis, coagulation, bacterial reverse mutation and in vivo thrombosis, intracutaneous reactivity test, pyrogen test and subchronic systemic toxicity test; all of the results meet the relevant international standards. The muscle implantation of the sintered ePTFE membrane into rabbits indicates acceptable inflammatory reactions of our sintered ePTFE membrane fabricated on industrial scale. Such a medical-grade raw material with the unique physical form and condensed-state microstructure is expected to afford an inert biomaterial potentially for stent-graft membrane.

A case of a coronary covered stent for repeated restenosis at the anastomosis site between saphenous vein graft and graft prosthesis

A 56-year-old man was admitted with a diagnosis of non-ST-segment elevation myocardial infarction, after surgery for total arch replacement, aortic root replacement with a mechanical aortic valve, and coronary artery reconstruction by the Piehler method for acute aortic dissection. Coronary angiography (CAG) revealed a 99% stenosis of the anastomosis site between the J Graft (Japan Lifeline, Tokyo, Japan) and the saphenous vein graft (SVG), which was distally sutured to his right coronary artery (posterior descending artery). After percutaneous coronary intervention (PCI) with a drug-eluting stent to the anastomosis site, repeated in-stent restenosis unfortunately occurred. Despite repeated PCIs, he was again admitted due to exertional angina pectoris, with proven inferior myocardial ischemia by stress myocardial perfusion imaging. We therefore decided to use a coronary covered stent for the anastomosis site to seal neointimal proliferation. GRAFTMASTER 2.8/19 mm (Abbott, CA, USA) was implanted in the anastomosis site, and a follow-up CAG one-year later revealed that the covered stent was clearly opened. To the best of our knowledge, this is the first paper to demonstrate the usefulness of a covered stent for repeated restenosis of the anastomosis site between SVG and graft prostheses. <Learning objective: A coronary covered stent is a stent with a membrane designed to seal the rupture site in cases with a coronary rupture. However, coronary covered stent implantation is an optional method in cases with repeated restenosis of the anastomosis site between the saphenous vein graft and graft prosthesis.>.

Outcomes of patients who undergo elective covered stent treatment for coronary artery aneurysms

BACKGROUND

Coronary artery aneurysms (CAA) are reported in up to 5% of patients undergoing coronary angiography. Treatment of CAAs with covered stents has been reported in several case reports, however there is limited evidence available on the effectiveness and safety of this interventional practice.

PURPOSE

To evaluate the current practice and outcomes of elective treatment of coronary artery aneurysms with covered stents.

METHODS

We conducted a systematic review of published case reports and case series of patients presenting with CAA that have been treated with covered stents in a non-emergency setting.

RESULTS

A total of 63 case reports and 3 case series were included in the final analysis comprising data from 81 patients. The treated CAA was situated in a native coronary artery in 92.6%, and in a saphenous vein graft in 7.4%. Procedural success was achieved in 95.1%. The types of stents used were mainly polytetrafluoroethylene (75.3%) and Papyrus (11.1%). In 11.0% of cases additional abluminal drug eluting stents (DES) and in 6.8% additional adluminal DES were implanted. After a mean follow up of 13.4 months overall major adverse cardiovascular events (MACE), mortality, myocardial infarction, stroke, stent thrombosis and target lesion revascularization were reported in 26.2, 0.0, 7.6, 0.0, 4.6 and 18.5% of cases, respectively.

CONCLUSIONS

The use of covered stents for elective treatment of CAA appears to be effective and reasonably safe. Nevertheless, it is associated with higher MACE rate, driven mainly by higher target lesion revascularization. Further studies, particularly in form of randomized trials and controlled registries are warranted to identify patients who might profit the most from this procedure.

Clinical Outcomes of Self-Made Polyurethane-Covered Stent Implantation for the Treatment of Coronary Artery Perforations

Objectives

The present study aimed to investigate the short- and long-term clinical outcomes of self-made polyurethane-covered stents (PU-CS) in patients for the management of coronary artery perforation (CAP) during percutaneous coronary intervention (PCI).

Background

Coronary artery perforation is reckoned as a serious complication in PCI and associated with considerable morbidity and mortality. Covered stents have been used for treating the life-threatening CAP during PCI. But in some catheterization laboratories, no commercial CS is immediately available when there is an urgent need for CS to rescue the coronary rupture site.

Methods

We retrospectively identified 24 patients who underwent 31 self-made PU-CS implantations due to CAP in Zhongshan Hospital, Fudan University, from June 2015 to January 2020.

Results

The total procedural success rate of CS to seal the perforation was 79.2%. Nine patients (37.5%) developed cardiac tamponade, of which 8 patients (33.3%) underwent pericardiocentesis and 4 patients (16.7%) underwent cardiac surgeries. Except for 4 cardiac death cases (16.7%), none of myocardial infarction (MI), target lesion revascularization (TLR), and stent thrombosis (ST) was reported during hospital stay. Data from 22 patients (91.7%) were available at 610.4 ± 420.9 days of follow-up. Major adverse cardiac events (MACE) occurred in 6 patients (27.3%), including 5 cases of cardiac death and one TLR case.

Conclusions

Self-made PU-CS demonstrates high rates of successful delivery and sealing of severe CAP during PCI. Although the in-hospital mortality remains high after PU-CS implantation, the long-term follow-up shows favorable clinical outcomes, indicating the feasibility of PU-CS in treating CAP.

Clinical Outcomes After Implantation of Polyurethane-Covered Cobalt-Chromium Stents: Insights from the Papyrus-Spain Registry

BACKGROUND/PURPOSE

The main indication of covered stents (CS) is coronary artery perforation (CAP), but, they have been increasingly used in other scenarios. Data on the long-term follow-up of CS is limited, and no studies have been conducted specifically using new-generation polyurethane-covered cobalt-chromium Papyrus CS.

PURPOSE

to evaluate the clinical outcomes after hospital discharge of Papyrus CS and to compare their outcome after implantation in CAP or coronary artery aneurysms (CAA).

METHODS/MATERIALS

We evaluated the baseline clinical characteristics, lesion subsets, procedural features and the outcomes after initial discharge of Papyrus CS implanted in 17 high-PCI-volume centers.

RESULTS

127 Papyrus CS were implanted in 108 patients (68 ± 1 years; 82.8% male) admitted for stable coronary disease (32.3%), NSTEMI (42.4%) or STEMI (25.3%). The number of CS per patient was 1.2 ± 0.6 (diameter: 3.5 ± 1.7 mm; length: 18.5 ± 3.7 mm). Angiographic success rate was 96%. CS diameter was larger in CAA (CAP:3.04 ± 0.5 mm vs CAA:4.1 ± 2.7 mm; p = .022). Intracoronary imaging techniques were used more frequently in CAA (p < .0001). After a mean follow-up of 22 ± 16 months, the major cardiovascular adverse events (MACE) rate was 7.1% [cardiac death: 2%, Myocardial infarction: 5%, Target Lesion Revascularization: 5% and Stent Thrombosis (ST): 3%]. MACE rate was similar in CAP (7.7%) and CAA (7.1%) (p = .9). However, CAA showed a higher ST rate (CAP: 0% vs CA: 7.1%; p = .04).

CONCLUSION

After hospital discharge, clinical outcomes after Papyrus CS implantation are acceptable (considering the clinical scenario and compared with other treatment alternatives) with no significant differences in the MACE rate between those implanted in CAA or in CAP. However, CAA group showed a higher ST rate.

Outcomes of patients who undergo percutaneous coronary intervention with covered stents for coronary perforation: A systematic review and pooled analysis of data

OBJECTIVES

This review aims to evaluate the adverse outcomes for patients after treatment with covered stents.

BACKGROUND

Coronary perforation is a potentially fatal complication of percutaneous coronary revascularization which may be treated using covered stents. Studies have evaluated long-term outcomes among patients who received these devices, but hitherto no literature review has taken place.

METHODS

We conducted a systematic review of adverse outcomes for patients after treatment with covered stents. Data from studies were pooled and outcomes were compared according to stent type.

RESULTS

A total of 29 studies were analyzed with data from 725 patients who received covered stents. The proportion of patients with chronic total occlusions, vein graft percutaneous coronary intervention (PCI), intracoronary imaging and rotational atherectomy were 16.9, 11.5, 9.2, and 6.6%, respectively. The stents used were primarily polytetrafluoroethylene (PTFE) (70%) and Papyrus (20.6%). Mortality, major adverse cardiovascular events, pericardiocentesis/tamponade and emergency surgery were 17.2, 35.3, 27.1, and 5.3%, respectively. Stratified analysis by use of PTFE, Papyrus and pericardial stents, suggested no difference in mortality (p = .323), or target lesion revascularization (p = .484). Stent thrombosis, pericardiocentesis/tamponade and emergency coronary artery bypass surgery (CABG) occurred more frequently in patients with PTFE stent use (p = .011, p = .005, p = .012, respectively). In-stent restenosis was more common with pericardial stent use (<.001, pooled analysis for first- and second-generation pericardial stents).

CONCLUSIONS

Cases of coronary perforation which require implantation of a covered stent are associated with a high rate of adverse outcomes. The use of PTFE covered stents appears to be associated with more stent thrombosis, pericardiocentesis/tamponade, and emergency CABG when compared to Papyrus or pericardial stents.

Is a covered stent justifiable in the treatment of coronary artery perforation? An observational analysis of long-term results of two different covered stent types

OBJECTIVES

In this retrospective observational study, we investigate outcome of patients treated with or without covered stent (CS) implantation in the management of coronary artery perforation (CAP) during coronary intervention.

BACKGROUND

CSs have shown to be effective devices to achieve acute hemostasis in large CAP. However, doubts have been raised regarding their long-term outcome.

METHODS

Data of 19 061 PCI procedures during a 10-year period were reviewed. Fifty-five cases of large CAP were withheld (Ellis type 2, 3 or cavity spilling). All medical and procedural records of these cases were retrospectively reviewed.

RESULTS

Twenty-four (43.6%) patients were treated with CS implantation (15 polytetrafluoroethylene and 9 pericardium CSs). Twenty-six (47.3%) patients were managed without CS implantation, of whom five had unsuccessful delivery of a CS (stent delivery failure 17.2%). Although significantly more Ellis type-3 perforations were present in the CS group compared to the Non-CS group (75.0% vs 45.2%; P = 0.03), in-hospital mortality was not significantly different (8.3% vs 6.4%; [P = 0.79]). We observed a high rate of CS restenosis (29.2%) but a lower rate of CS thrombosis (4.2%). Despite these observations, 5-year MACE and all-cause mortality were not significantly different between CS and Non-CS group (respectively, 58.8% vs 50.0% (P = 0.26) and 26.7% vs 13.3% (P = 0.36)).

CONCLUSION

Although deliverability of CSs was not flawless and a high rate of CS restenosis appeared, short- and long-term outcome were comparable between patients treated with or without CS. Therefore, CSs are justifiable in the treatment of CAP.