Research

Fung RK, Stellios J, Bannon PG, Ananda A, Forrest P

Anaesth Intensive Care 2017 07;45(4):527-528

PMID: 28673230

Abstract

Vanags LZ, Tan JTM, Santos M, Michael PS, Ali Z, Bilek MMM, Wise SG, Bursill CA

Nanomedicine 2017 Oct;13(7):2141-2150

PMID: 28668625

Abstract

We utilized a plasma activated coating (PAC) to covalently bind the active component of high density lipoproteins (HDL), apolipoprotein (apo) A-I, to stainless steel (SS) surfaces. ApoA-I suppresses restenosis and thrombosis and may therefore improve SS stent biocompatibility. PAC-coated SS significantly increased the covalent attachment of apoA-I, compared to SS alone. In static and dynamic flow thrombosis assays, PAC+apoA-I inhibited thrombosis and reduced platelet activation marker p-selectin. PAC+apoA-I reduced smooth muscle cell attachment and proliferation, and augmented EC attachment to PAC. We then coated PAC onto murine SS stents and found it did not peel or delaminate following crimping/expansion. ApoA-I was immobilized onto PAC-SS stents and was retained as a monolayer when exposed to pulsatile flow in vivo in a murine stent model. In conclusion, ApoA-I immobilized on PAC withstands pulsatile flow in vivo and retains its bioactivity, exhibiting anti-thrombotic and anti-restenotic properties, demonstrating the potential to improve stent biocompatibility.

Paterson HS, Bannon PG, Taggart DP

J. Thorac. Cardiovasc. Surg. 2017 Jun;

PMID: 28651939

Abstract

McBride KE, Solomon MJ, Bannon PG, Young JM

ANZ J Surg 2017 Jun;87(6):431-432

PMID: 28585756

Abstract

Moore BM, Ng HKB, Naoum C, Simmons L, Cartwright BL, Wilson MK, Ng MKC

Circ Cardiovasc Interv 2017 Jun;10(6)

PMID: 28566291

Abstract

Indja B, Fanning JP, Maller JJ, Fraser JF, Bannon PG, Vallely M, Grieve SM

Br J Anaesth 2017 May;118(5):680-688

PMID: 28510745

Abstract

Cognitive dysfunction is a poorly understood but potentially devastating complication of cardiac surgery. Clinically meaningful assessment of cognitive changes after surgery is problematic because of the absence of a means to obtain reproducible, objective, and quantitative measures of the neural disturbances that cause altered brain function. By using both structural and functional connectivity magnetic resonance imaging data to construct a map of the inter-regional connections within the brain, connectomics has the potential to increase the specificity and sensitivity of perioperative neurological assessment, permitting rational individualized assessment and improvement of surgical techniques.

Zhu MZL, Newman MA, Joshi P, Passage J

Heart Lung Circ 2017 Nov;26(11):e82-e85

PMID: 28506647

Abstract

Advancements in bioprosthetic valve technology have greatly enhanced the haemodynamic performance and long-term durability of tissue valves. These features, along with the key advantage of avoiding lifelong anticoagulation, have made bioprosthetic valves increasingly attractive for clinicians and patients alike. The St Jude Trifecta valve is a novel, bovine pericardial bioprosthesis with promising early data for performance and safety. However, no prosthetic valve is perfect and prosthesis failure can occur with even the most reliable and well-designed devices. We report a case of early and acute structural deterioration (stent-post leaflet rupture) of the Trifecta valve, explanted after 33 months, in a 76-year-old male.

Ramponi F, Flynn CD, Wilson MK

Heart Lung Circ 2017 Apr;

PMID: 28456599

Abstract

BACKGROUND: Patients with a permanent tracheostomy requiring coronary surgery represent a unique challenge, being at increased risk of sternal wound complications, mediastinitis and stoma necrosis. Several techniques have been described including manubrium sparing sternotomy, thoracoscopic internal mammary harvest and hybrid revascularization.

HOW TO DO IT: We report a case of robotic assisted (daVinci(®)Xi™ Surgical System) total arterial off-pump revascularization in a patient with previous laryngectomy and permanent tracheostomy. The main advantage of this approach was to minimize the risk of post-operative sternal complication and mediastinatis, whilst still providing the prognostic benefit of total arterial grafting and the neurological advantage of the aorta no-touch technique.

Kondyurina I, Wise SG, Ngo AKY, Filipe EC, Kondyurin A, Weiss AS, Bao S, Bilek MMM

Biomed Mater 2017 Jul;12(4):045002

PMID: 28435148

Abstract

Polyurethanes are a diverse class of polymers, with independently tunable mechanical and biodegradation properties making them a versatile platform material for biomedical implants. Previous iterations have failed to adequately embody appropriate mechanical and biological properties, particularly for vascular medicine where strength, compliance and multifaceted biocompatibility are required. We have synthesized a new polyurethane formulation with finely tuned mechanical properties, combining high strength and extensibility with a low Young’s modulus. Additional cross-linking during synthesis enhanced stability and limits leaching. Under cyclic testing, hysteresis was minimal following completion of the initial cycles, indicating the robustness of the material. Building on this platform, we used plasma immersion ion implantation to activate the polymer surface and functionalized it with recombinant human tropoelastin. With tropoelastin covalently bound to the surface, human coronary endothelial cells showed improved attachment and proliferation. In the presence of heparinized whole blood, tropoelastin-coated polyurethane showed very low thrombogenicity in both static and flow conditions. Using this formulation, we synthesized robust, elastic prototype conduits which easily retained multiple sutures and were successfully implanted in a pilot rat aortic interposition model. We have thus created an elastic, strong biomaterial platform, functionalized with an important regulator of vascular biology, with the potential for further evaluation as a new synthetic graft material.

Chan AH, Tan RP, Michael PL, Lee BS, Vanags LZ, Ng MK, Bursill CA, Wise SG

PLoS ONE 2017;12(3):e0174773

PMID: 28355300

Abstract

Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL) we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM) analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP). This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days). We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance.