Category: General

J Cardiovasc Dev Dis. 2022 Aug 22;9(8):282. doi: 10.3390/jcdd9080282.

ABSTRACT

Aortic stenosis is the most common valve disease requiring surgery or percutaneous treatment. Since the first-in-man implantation in 2002 we have witnessed incredible progress in transcatheter aortic valve implantation (TAVI). In this article, we review the technical aspects of TAVI development with a look at the future. Durability, low thrombogenicity, good hydrodynamics, biocompatibility, low catheter profile, and deployment stability are the attributes of an ideal TAVI device. Two main design types exist-balloon-expandable and self-expanding prostheses. Balloon-expandable prostheses use a cobalt-chromium alloy frame providing high radial strength and radiopacity, while the self-expanding prostheses use a nickel-titanium (Nitinol) alloy frame, which expands to its original shape once unsheathed and heated to the body temperature. The valve is sewn onto the frame and consists of the porcine or bovine pericardium, which is specially treated to prevent calcinations and prolong durability. The lower part of the frame can be covered by polyethylene terephthalate fabric or a pericardial skirt, providing better sealing between the frame and aortic annulus. The main future challenges lie in achieving lower rates of paravalvular leaks and new pacemaker implantations following the procedure, lower delivery system profiles, more precise positioning, longer durability, and a good hemodynamic profile. Patient-specific design and the use of autologous tissue might solve these issues.

PMID:36005446 | PMC:PMC9409777 | DOI:10.3390/jcdd9080282

J Vasc Surg Cases Innov Tech. 2022 May 3;8(2):300-304. doi: 10.1016/j.jvscit.2022.04.002. eCollection 2022 Jun.

ABSTRACT

Cryopreserved vein allografts are used as alternative conduits for infrainguinal bypass but are prone to aneurysmal degeneration. A 60-year-old man presented with a pulsatile, tender right groin mass 2 years after thrombosis of a cryopreserved vein jump graft emanating from a prosthetic axillary to profunda bypass. Intraoperatively, the aneurysm was consistent with isolated dilatation of the hood of the thrombosed cryopreserved vein graft. This was excised and repaired with bovine pericardial patch angioplasty. The patient recovered with no recurrence for 2 years. Aneurysmal degeneration of the cryopreserved vein allograft can occur even after graft thrombosis.

PMID:35669278 | PMC:PMC9166410 | DOI:10.1016/j.jvscit.2022.04.002

Biomaterials. 2022 Sep 6;289:121782. doi: 10.1016/j.biomaterials.2022.121782. Online ahead of print.

ABSTRACT

Bioprosthetic heart valves (BHV) fabricated from heterograft tissue, such as glutaraldehyde pretreated bovine pericardium (BP), are the most frequently used heart valve replacements. BHV durability is limited by structural valve degeneration (SVD), mechanistically associated with calcification, advanced glycation end products (AGE), and serum protein infiltration. We investigated the hypothesis that anti-AGE agents, Aminoguanidine, Pyridoxamine [PYR], and N-Acetylcysteine could mitigate AGE-serum protein SVD mechanisms in vitro and in vivo, and that these agents could mitigate calcification or demonstrate anti-calcification interactions with BP pretreatment with ethanol. In vitro, each of these agents significantly inhibited AGE-serum protein infiltration in BP. However, in 28-day rat subdermal BP implants only orally administered PYR demonstrated significant inhibition of AGE and serum protein uptake. Furthermore, BP PYR preincubation of BP mitigated AGE-serum protein SVD mechanisms in vitro, and demonstrated mitigation of both AGE-serum protein uptake and reduced calcification in vivo in 28-day rat subdermal BP explants. Inhibition of BP calcification as well as inhibition of AGE-serum protein infiltration was observed in 28-day rat subdermal BP explants pretreated with ethanol followed by PYR preincubation. In conclusion, AGE-serum protein and calcification SVD pathophysiology are significantly mitigated by both PYR oral therapy and PYR and ethanol pretreatment of BP.

PMID:36099713 | DOI:10.1016/j.biomaterials.2022.121782

Xenotransplantation. 2022 Sep 13:e12774. doi: 10.1111/xen.12774. Online ahead of print.

ABSTRACT

INTRODUCTION: Current bioprosthetic heart valve replacement options are limited by structural valvular deterioration (SVD) due to an immune response to the xenogenic scaffold. Autologous mesenchymal stem cell (MSC) recellularization is a method of concealing xenogenic scaffolds, preventing recipient immune recognition of xenogenic tissue heart valves, and potentially leading to reduction in SVD incidence. The purpose of this study is to examine the effects of autologous MSC recellularized tissue on the immune response of human whole blood to bovine pericardium (BP). We hypothesized that autologous MSC recellularization of BP will result in reduced pro-inflammatory cytokine production equivalent to autologous human pericardium.

METHODS: Bone marrow, human pericardium, and whole blood were collected from adult patients undergoing elective cardiac surgery. Decellularized BP underwent recellularization with autologous MSCs, followed by co-incubation with autologous whole blood. Immunohistochemical, microscopic, and quantitative immune analysis approaches were used.

RESULTS: We demonstrated that native BP, exposed to human whole blood, results in significant TNF-α and IL1β production. When decellularized BP is recellularized with autologous MSCs and exposed to whole blood, there is a significant reduction in TNF-α and IL1β production. Importantly, recellularized BP exposed to whole blood had similar production of TNF-α and IL1β when compared to autologous human pericardium exposed to human whole blood.

CONCLUSION: Our results suggest that preventing initial immune activation with autologous MSC recellularization may be an effective approach to decrease the recipient immune response, preventing recipient immune recognition of xenogeneic tissue engineered heart valves, and potentially leading to reduction in SVD incidence.

PMID:36098060 | DOI:10.1111/xen.12774

J Cerebrovasc Endovasc Neurosurg. 2022 Sep 7. doi: 10.7461/jcen.2022.E2020.11.004. Online ahead of print.

ABSTRACT

Vascular compression of neural tissue causing neurological symptoms is a wellknown phenomenon. This is commonly seen in trigeminal neuralgia and, less commonly, in hemifacial spasm by small arteries, which can be treated by microvascular decompression. Rarely, larger arteries, such as the vertebral arteries, may compress the brainstem. This can lead to symptoms of pontine or medullary distress like hemiparesis, dysphagia, or respiratory distress. This is treated by macrovascular decompression. Due to the rare and heterogenous nature of this disease, there is no standardized approach. We describe a novel technique whereby the vertebrobasilar system is mobilized anterolaterally towards the occipital condyle with a sling to decompress the brainstem. We report two cases of vertebrobasilar dolichoectasia causing brainstem compression. A carotid patch graft sling with anterolateral mobilization to the occipital condyle is described as a surgical nuance to macrovascular decompressive surgery. Briefly, the vertebral artery was identified and dissected away from the brainstem and the bulbar cranial nerves. Bovine pericardium graft was used to create a sling around the artery by suturing the two ends together. The sling was then fixed either to the occipital condyle using cranial plating screws or suturing to the dura of the occipital condyle. A novel surgical technique for management of vertebrobasilar dolichoectasia causing brainstem compression with progressive neurological deterioration is reported. Anatomical location and the offending vessel should guide neurosurgeons to select the best surgical option to achieve complete decompression of the involved neural structures.

PMID:36068675 | DOI:10.7461/jcen.2022.E2020.11.004