Out of the Mind of Edward B. Diethrich: The Development of the Polytetrafluoroethylene-Covered Coronary Stent

Expanded Polytetrafluoroethylene Membranes for Vascular Stent Coating: Manufacturing, Biomedical and Surgical Applications, Innovations and Case Reports

Coated stents are defined as innovative stents surrounded by a thin polymer membrane based on polytetrafluoroethylene (PTFE)useful in the treatment of numerous vascular pathologies. Endovascular methodology involves the use of such devices to restore blood flow in small-, medium- and large-calibre arteries, both centrally and peripherally. These membranes cross the stent struts and act as a physical barrier to block the growth of intimal tissue in the lumen, preventing so-called intimal hyperplasia and late stent thrombosis. PTFE for vascular applications is known as expanded polytetrafluoroethylene (e-PTFE) and it can be rolled up to form a thin multilayer membrane expandable by 4 to 5 times its original diameter. This membrane plays an important role in initiating the restenotic process because wrapped graft stent could be used as the treatment option for trauma devices during emergency situations and to treat a number of pathological vascular disease. In this review, we will investigate the multidisciplinary techniques used for the production of e-PTFE membranes, the advantages and disadvantages of their use, the innovations and the results in biomedical and surgery field when used to cover graft stents.

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.

Belt and suspenders: Why it pays to protect and cover during carotid stenting

Carotid stenting results show equivalence to carotid endarterectomy. Most patients undergoing carotid intervention are asymptomatic. Using embolic protection with a covered mesh stent shows promise in this first large multicenter study.