The pericardium covered stent (PCS)

Mammalian Pericardium-Based Bioprosthetic Materials in Xenotransplantation and Tissue Engineering

Bioprosthetic materials based on mammalian pericardium tissue are the gold standard in reconstructive surgery. Their application range covers repair of rectovaginal septum defects, abdominoplastics, urethroplasty, duraplastics, maxillofacial, ophthalmic, thoracic and cardiovascular reconstruction, etc. However, a number of factors contribute to the success of their integration into the host tissue including structural organization, mechanical strength, biocompatibility, immunogenicity, surface chemistry, and biodegradability. In order to improve the material's properties, various strategies are developed, such as decellularization, crosslinking, and detoxification. In this review, the existing issues and long-term achievements in the development of bioprosthetic materials based on the mammalian pericardium tissue, aimed at a wide-spectrum application in reconstructive surgery are analyzed. The basic technical approaches to preparation of biocompatible forms providing continuous functioning, optimization of biomechanical and functional properties, and clinical applicability are described.

Multiparametric Optical Bioimaging Reveals the Fate of Epoxy Crosslinked Biomeshes in the Mouse Subcutaneous Implantation Model

Biomeshes based on decellularized bovine pericardium (DBP) are widely used in reconstructive surgery due to their wide availability and the attractive biomechanical properties. However, their efficacy in clinical applications is often affected by the uncontrolled immunogenicity and proteolytic degradation. To address this issue, we present here in vivo multiparametric imaging analysis of epoxy crosslinked DBPs to reveal their fate after implantation. We first analyzed the structure of the crosslinked DBP using scanning electron microscopy and evaluated proteolytic stability and cytotoxicity. Next, using combination of fluorescence and hypoxia imaging, X-ray computed microtomography and histology techniques we studied the fate of DBPs after subcutaneous implantation in animals. Our approach revealed high resistance to biodegradation, gradual remodeling of a surrounding tissue forming the connective tissue capsule and calcification of crosslinked DBPs. These changes were concomitant to the development of hypoxia in the samples within 3 weeks after implantation and subsequent induction of angiogenesis and vascularization. Collectively, presented approach provides new insights on the transplantation of the epoxy crosslinked biomeshes, the risks associated with its applications in soft-tissue reconstruction and can be transferred to studies of other types of implants.

Single Center 7 Year Experience of Coronary Artery Perforation: Angiographic and Procedural Characteristics, Management and Outcome

Context:

Coronary artery perforation is a rare but potentially catastrophic complication of percutaneous coronary intervention (PCI). It is infrequent complication of PCI.

Aims:

The objective of the study is to report the 7-year experience of coronary artery perforation with respect to incidence, clinical and angiographic characteristics, management and outcomes.

Settings and Design:

The study involved retrospective analysis of single centre 7 years of percutaneous coronary intervention data. Patients who had complication of coronary artery perforation during PCI were identified and included in the study.

Subjects and Methods:

Retrospective analysis of clinical, angiographic and procedural characteristics as well as management and outcome of coronary artery perforation was done.

Statistical Analysis Used:

The whole data were tabulated, variables were presented as mean and percentages and comparison was done within them.

Results:

A total of 37 cases of coronary artery perforation were identified from 4532 PCI performed. Most of the coronary artery perforation belonged to Ellis Type II and Type III (both n = 15) followed by Type III CS and Type I. Lesions belonged to AHC/AHA Type C in 31 cases. Most frequent mechanism of coronary artery perforation was related to the use of guidewire and balloon (both n = 17). The total of 8 cases presented with cardiac tamponade requiring pericardiocentesis. Eleven cases required emergency covered stent implantation. In two cases microcoil was used while one case required polyvinyl alcohol particles to seal the perforation site. There was no in-hospital mortality while 30-day mortality occurred in one patient. One case was referred for emergency surgery.

Conclusions:

Coronary artery perforation is rare but potentially fatal complication of percutaneous coronary intervention. Complication of coronary artery perforation can be managed effectively in the catheterization laboratory without the need of emergency of bailout surgery and in-hospital outcomes remain good in the majority of cases.

Endovascular treatment of a hepatic artery pseudoaneurysm using a novel pericardium covered stent

Visceral and renal artery aneurysms (VRAAs) and pseudoaneurysms are rare. Their increasing incidence is largely thought to be due to advances in medical imaging. Twenty percent of VRAAs occur in hepatic arteries, with approximately fifty percent of these represented by pseudoaneurysms, which are prone to spontaneous rupture. Many treatments for VRAAs exist, with the endovascular approach being favoured. Treatment aims to preserve visceral perfusion and exclude the aneurysm; however, complex aneurysms may require parent artery or end-organ sacrifice. Covered stents allow rapid aneurysm exclusion while preserving parent artery patency, a favourable outcome when parent artery or end-organ sacrifice is undesirable. The AneuGraft pericardium covered stent (PCS) combines the benefits of a low-profile covered stent with those of a low immunogenic material. We describe the endovascular treatment of a patient with a hepatic artery pseudoaneurysm, where parent artery sacrifice was considered unacceptable. The AneuGraft PCS was used to provide immediate and complete exclusion, with dual antiplatelet therapy for 1 week, followed by single antiplatelet use. The procedure was a technical success, with preservation of the hepatic arteries and complete exclusion of the pseudoaneurysm. There were no complications immediately following the procedure or on post-procedural follow-up. The pseudoaneurysm remained excluded at 6-week CT angiogram (CTA) follow-up. This case describes a safe and effective method for completely excluding a complex pseudoaneurysm, utilising the AneuGraft PCS, allowing for the potential management of a wider range of aneurysms with unfavourable morphology.

Acute and long-term outcomes after polytetrafluoroethylene or pericardium covered stenting for grade 3 coronary artery perforations: Insights from G3-CAP registry

BACKGROUND

Covered stent (CS) implantation is considered a useful device in the setting of Grade III Coronary Perforation (G3CP), one of the most harmful PCI complication. However, data regarding efficacy of this device and clinical outcomes are still limited.

METHODS AND RESULTS

From 1993 to 2015, among 97,779 patients from 9 European centres undergoing PCI, 224 patients had G3CP (0.23%), and 102 patients were managed with CS implantation (96 with PTFE, 6 with pericardium). Device oriented composite endpoint (DOCE), a composite of cardiac death, target lesion revascularization, and stent thrombosis (ST) in-hospital and at long term follow-up were evaluated. G3-CP perforations were successfully sealed with CS in 88 patients (86.3%) with need of intraprocedural pericardiocentesis in one-third of cases. Protamine as heparin reversal agent was administered in 36 (35%) of cases. The cumulative incidence of in-hospital DOCE were 16.6% (17/102): death 14.7%, TLR 2.9%, ST 3.9%. At long-term follow-up (mean 42 ± 38 months), DOCE rates occurred in 19.7%: death 7.4%, TLR 11%, and ST 6.2%. Indication to Dual Antiplatelet Therapy (DAPT) was lifelong in 20% of cases, 1 to 6 months in 22.5% and 12-months in 57.5% without differences in long-term DOCE before and after DAPT interruption (8.0 vs. 6.6%, respectively, P = 0.20).

CONCLUSIONS

Use of CS was successful in sealing grade 3 coronary artery perforations in the majority of cases. Beside the high rate of clinical events at short and long-term, ST remains the leading cause of device failure.

Tissue processing techniques for fabrication of covered stents for small-diameter vascular intervention

Animal-derived pericardial tissue is a widely used biomaterial typically treated with glutaraldehyde (GA) to achieve immunological acceptance and long-term durability. However, GA fixation of biological tissue is associated with long-term failure due to degeneration and calcification. In this study, we evaluated two alternative tissue processing methods for the fabrication of pericardial tissue covered stents: detergent-based decellularization (decell) and limited exposure to GA (gentle-glut). Processed pericardial tissues were extensively characterized both in-vitro and in-vivo. Small-diameter covered stents were fabricated and the ability to seal perforation was evaluated in a flow circuit under physiological blood flow conditions. Results indicate that decell-treated tissue appeared with preserved architecture, tissue strength and stability. Gentle-glut tissue appeared with preserved architecture and increased tissue stability, compared to fresh, unprocessed tissue. Reduction of bioburden was demonstrated for both types of alternative treatments, as for GA fixation. Tensile testing demonstrated that both decell- and gentle-glut treated tissues respond better to low strain, as may occur during balloon inflation and stent deployment. Upon subcutaneous implantation in mice, gentle-glut and to a greater degree decell-treated tissue, elicit better host response, with evidence of active tissue remodeling and no detectable calcification, as compared with GA-treated tissue. Small-diameter stents covered with tissues from all groups successfully sealed perforation under physiological blood flow conditions in-vitro, without compromising flow. In summary, covered stents may perform better with pericardial tissue processed according to the methods described in this study. Adopting this methodology to other types of cardiovascular implants and tissues is also suggested.

STATEMENT OF SIGNIFICANCE

Pericardial tissue is a widely used biomaterial for cardiovascular implants, such as covered stents. The use of glutaraldehyde (GA) has become the method of choice for pericardial tissue fixation, making it immunologically acceptable in humans. However, GA-treated tissue is prone to several problems, such as degeneration and calcification that may lead to long-term failure. Here, we studied two alternative tissue processing techniques: fixative-free decellularization and limited exposure to GA. We've shown that both methods achieve better mechanical properties and promote better host acceptance, tissue remodeling and long-term durability. Since the availability of autologous tissue for transplantation is limited, these methods should be adopted for other types of cardiovascular devices, such as bioprosthetic valves, ultimately achieving better long-term results for patients.

Clinical Characteristics and Management of Coronary Artery Perforations: A Single-Center 11-Year Experience and Practical Overview

Background

Coronary artery perforation (CAP) is a potentially lethal complication of percutaneous coronary intervention. We report on the incidence, clinical characteristics, and management of iatrogenic coronary perforations based on an 11‐year single‐center experience.

Methods and Results

From February 9, 2005, through November 20, 2016, 150 CAP cases were identified from our percutaneous coronary intervention database of 21 212 procedures (0.71%). Mean age of CAP patients was 66±11 years, and 62.7% were male. Treated lesion type was B2/C in 94.6%, and 31.3% were chronic total occlusions. Nonworkhorse guidewires were applied in 74.3%. CAP types were Ellis type I in 2.9%, Ellis type II in 40.4%, Ellis type III in 54.8%, and Ellis type III cavity spilling in 1.9%. CAP treatment was conservative (including prolonged balloon inflation) in 73.3%. Covered stents, coiling, and fat embolization were used in 24.0%, 0.7%, and 2.0%, respectively. Pericardiocentesis for tamponade was required for 72 patients (48.0%), of whom 28 were initially unrecognized. Twelve patients (12.7%) required emergency cardiac surgery to alleviate tamponade. Periprocedural myocardial infarction occurred in 34.0%, and in‐hospital all‐cause mortality was 8.0%. All‐cause mortality accrued to 10.7% at 30 days and 17.8% at 1 year.

Conclusions

CAP is a rare complication of percutaneous coronary intervention, but morbidity and mortality are considerable. Early recognition and adequate management are of paramount importance.

Coronary covered stents

Covered stents offer an effective bail-out strategy in vessel perforations, are an alternative to surgery for the exclusion of coronary aneurysms, and have a potential role in the treatment of friable embolisation-prone plaques. The aim of this manuscript is to offer an overview of currently available platforms and to report results obtained in prior studies.

Short-Term and Long-Term Outcomes After Polytetrafluoroethylene-Covered Stent Implantation for the Treatment of Coronary Perforation

This study sought to evaluate the short-term and 3-year outcomes of polytetrafluoroethylene-covered stent (PCS) for patients with coronary perforation. Implantation of a PCS has improved the immediate clinical outcomes of patients with coronary perforation. However, there are few reports regarding long-term outcomes. We evaluated a total of 57 patients who were treated with PCS for coronary perforation from April 2004 to March 2015 at a single high-volume center in Japan. Landmark analysis was performed at 30 days to determine short-term and long-term outcomes. Major adverse cardiac events (MACE) were defined as death, myocardial infarction, target vessel revascularization, and requirement for surgical repair. Of 285 patients who experienced coronary perforation, 57 patients (20%) were treated with PCS. The MACE rates were 28% at 30 days, 22% at 1 year, and 38% at 3 years. 30-day MACE was mainly driven by high rates of myocardial infarction (18%) and surgical repair (16%). The rates of target lesion revascularization were 8% and 12% at 1 and 3 years, respectively. Definite stent thrombosis was reported in 2 patients during the follow-up period. In conclusion, despite the relatively high incidence of MACE during early stage of follow-up, implantation of a PCS provides acceptable late clinical outcomes.

Secondary revascularization after CABG surgery

CABG surgery is an effective way to improve symptoms and prognosis in patients with advanced coronary atherosclerotic disease. Despite multiple improvements in surgical technique and patient treatment, graft failure after CABG surgery occurs in a time-dependent fashion, particularly in the second decade after the intervention, in a substantial number of patients because of atherosclerotic progression and saphenous-vein graft (SVG) disease. Until 2010, repeat revascularization by either percutaneous coronary intervention (PCI) or surgical techniques was performed in these high-risk patients in the absence of specific recommendations in clinical practice guidelines, and within a culture of inadequate communication between cardiac surgeons and interventional cardiologists. Indeed, some of the specific technologies developed to reduce procedural risk, such as embolic protection devices for SVG interventions, are largely underused. Additionally, the implementation of secondary prevention, which reduces the need for reintervention in these patients, is still suboptimal. In this Review, graft failure after CABG surgery is examined as a clinical problem from the perspective of holistic patient management. Issues such as the substrate and epidemiology of graft failure, the choice of revascularization modality, the specific problems inherent in repeat CABG surgery and PCI, and the importance of secondary prevention are discussed.

Endovascular treatment of internal carotid and vertebral artery aneurysms using a novel pericardium covered stent

Intracranial aneurysm is a fairly common (often asymptomatic) condition. Subarachnoid hemorrhage associated with aneurysmal rupture is a potentially lethal event with a mortality rate as high as 50 percent and a high rate of disability among those who survive the initial hemorrhage, such that recently published guidelines support treatment of intracerebral aneurysms. The current treatment options include surgical clipping and endovascular treatment, but these are not without significant problems. Despite the trend toward endovascular treatment the rate of recurrence and complications is high. Current published evidence of the use of covered stent is limited to stents covered with polytetrafluoroethylene. It is now recognized that mammalian extracellular matrix represents an excellent scaffold material suitable for many therapeutic applications and glutaraldehyde treated pericardium has been widely used for many years due to its desirable features such as low immunogenicity and durability. This report describes the first published experience with the Aneugraft Pericardium Covered Stent (ITGI Medical, OR Akiva, Israel) in the treatment of internal carotid and vertebral artery aneurysms in three patients. In all three cases, the implantation of this novel device has resulted in successful closure of aneurysms.

Covered stents for coronary perforations: is there enough evidence?

Covered stents have shown discouraging results when tested on saphenous vein grafts and when attempting to prevent restenosis on native coronary arteries. However, covered stents seem to be a unique tool when a coronary artery perforation complicates percutaneous coronary intervention. Because a randomized clinical trial is not likely to be conducted in this bail-out scenario, the data supporting its use come from case reports and small-size retrospective studies. This review summarizes the available evidence supporting the use of covered stents to treat coronary perforations.

Design and characterization of an injectable pericardial matrix gel: a potentially autologous scaffold for cardiac tissue engineering

Following ischemic injury in the heart, little to no repair occurs, causing a progressive degeneration of cardiac function that leads to congestive heart failure. Cardiac tissue engineering strategies have focused on designing a variety of injectable scaffolds that range in composition from single-component materials to complex extracellular matrix (ECM)-derived materials. In this study, the pericardial ECM, a commonly used biomaterial, was investigated for use as an injectable scaffold for cardiac repair. It was determined that a solubilized form of decellularized porcine pericardium could be injected and induced to gel in vivo, prompting investigation with human pericardium, which has the decided advantage of offering an autologous therapy. Characterization showed that the matrix gels retained components of the native pericardial ECM, with extant protein and glycosaminoglycan content identified. The results of an in vitro migration assay indicate that the porcine pericardial matrix is a stronger chemoattractant for relevant cell types, but in vivo results showed that the two materials caused statistically similar amounts of neovascularization, demonstrating feasibility as injectable treatments. Potential stem cell mobilization was supported by the presence of c-Kit+ cells within the matrix injection regions. With this work, the pericardium is identified as a novel source for an autologous scaffold for treating myocardial infarction.