Research

Agostinho N, Robinson BM, Yan TD

ANZ J Surg 2017 Sep;87(9):E100-E101

PMID: 25682800

Abstract

Cao C, Yan TD, He J

Ann. Surg. Oncol. 2017 Nov;

PMID: 29159739

Abstract

Saxena A, Virk SA, Bowman SRA, Jeremy R, Bannon PG

Heart Lung Circ 2018 Apr;27(4):420-426

PMID: 29103675

Abstract

BACKGROUND: Cardiac surgical units must balance trainee education with the duty to provide optimal patient care. This is particularly challenging with valvular surgery, given the lower volume and increased complexity of these procedures. The present meta-analysis was conducted to assess the impact of trainee operator status on clinical outcomes following valvular surgery.

METHODS: Medline, Embase and CENTRAL databases were systematically searched for studies reporting clinical outcomes according to the training status of the primary operator (consultant or trainee). Data were extracted and meta-analysed according to pre-defined endpoints.

RESULTS: Eleven observational studies met the inclusion criteria, reporting on five patient cohorts undergoing mitral valve surgery (n=3975), six undergoing aortic valve replacement (AVR) (n=6236) and three undergoing combined AVR and coronary artery bypass grafting (CABG) (n=3495). Perioperative mortality was not significantly different between trainee and consultant cases for mitral valve surgery (odds ratio [OR] 0.92; 95% confidence interval [CI], 0.62-1.37), AVR (OR 0.67; 95% CI, 0.37-1.24), or combined AVR and CABG (OR 1.07; 95% CI, 0.40-2.85). The incidences of perioperative stroke, myocardial infarction, arrhythmias, acute renal failure, reoperation or wound infection were not significantly different between trainee and consultant cases. There was a paucity of mid-term survival data.

CONCLUSIONS: Valvular surgery cases performed primarily by trainees were not associated with adverse perioperative outcomes. These findings suggest the rigorous design of cardiac surgical trainee programs can sufficiently mitigate trainee deficiencies. However, studies with longer follow-up duration and echocardiographic data are required to assess long-term durability and safety.

Paterson HS, Bannon PG

Heart Lung Circ 2018 Feb;27(2):133-137

PMID: 29126818

Abstract

The use of composite coronary artery bypass grafts from the left internal mammary artery (LIMA) has increased over the last 20 years. Total arterial revascularisation can be achieved with two arterial conduits and is associated with a reduced risk of stroke. However, the traditional coronary bypass graft configurations of the in situ LIMA and aorto-coronary saphenous vein grafts remain as the mainstay of coronary bypass surgery in most centres. Concerns regarding composite Y grafts relate to (1) the adequacy of a single inflow for all coronary bypass grafts; (2) the risk of compromising the LIMA flow to the left anterior descending coronary artery; (3) the effects of competitive flow on graft patency; and (4) the use of sequential coronary anastomoses. The evidence upon which these concerns are based will be discussed along with the evidence relating to the use of the various second conduit options.

Meier S, Noack T, Mohr FW, Seeburger J, Passage J

Ann Cardiothorac Surg 2017 Jul;6(4):416-418

PMID: 28944184

Abstract

Lau JK, Roy P, Bing R, Bannon PG, Lowe HC

J Invasive Cardiol 2017 Sep;29(9):E99-E100

PMID: 28878100

Abstract

In this case, prompt stenting of the dissection entry flap allowed for stabilization and eventual healing of a severe catheter-induced aortic dissection, without resort to surgical intervention.

Paterson HS, Bannon PG

Ann Transl Med 2017 Aug;5(15):314

PMID: 28856154

Abstract

Fong LS, McLaughlin AJ, Okiwelu NL, Nordstrand IAJ, Newman M, Passage J, Joshi PV

Ann. Thorac. Surg. 2017 Sep;104(3):e291-e293

PMID: 28838533

Abstract

Caseous calcification of the mitral annulus (CCMA) is a rare variant of mitral annular calcification; it can manifest with conduction abnormalities or systemic embolization. It typically involves the posterior mitral annulus, and surgery is indicated for severe mitral valve dysfunction, for embolic complications or when the diagnosis is not certain. We describe a structured approach to the surgical management of CCMA using bovine pericardium to repair the defect.

Boyd JH, Edelman JJB, Scoville DH, Woo YJ

Ann Cardiothorac Surg 2017 May;6(3):248-254

PMID: 28706867

Abstract

Tricuspid regurgitation (TR) represents a significant disease process and when severe, is associated with increased mortality. Recent guidelines support a more aggressive approach to tricuspid valve (TV) surgery, especially when encountered with left-sided valvular pathology. While annuloplasty has been the standard treatment for TR, it may not provide as effective or durable a repair compared to annuloplasty combined with TV repair techniques. Several of these approaches are discussed including bicuspidalization, anterior leaflet augmentation, edge to edge repair, neochords, leaflet resection and combined approaches. Although patient cohorts in most of the studies examining these techniques are small, the long-term durability of TV repair is significant.

Liu R, Lo L, Lay AJ, Zhao Y, Ting KK, Robertson EN, Sherrah AG, Jarrah S, Li H, Zhou Z, Hambly BD, Richmond DR, Jeremy RW, Bannon PG, Vadas MA, Gamble JR

Circ. Res. 2017 Aug;121(5):512-524

PMID: 28701309

Abstract

RATIONALE: Thoracic aortic aneurysm (TAA) is a potentially lethal condition, which can affect individuals of all ages. TAA may be complicated by the sudden onset of life-threatening dissection or rupture. The underlying mechanisms leading to TAA formation, particularly in the nonsyndromal idiopathic group of patients, are not well understood. Thus, identification of new genes and targets that are involved in TAA pathogenesis are required to help prevent and reverse the disease phenotype.

OBJECTIVE: Here we explore the role of ARHGAP18, a novel Rho GAP expressed by smooth muscle cells (SMCs), in the pathogenesis of TAA.

METHODS AND RESULTS: Using human and mouse aortic samples, we report that ARHGAP18 levels were significantly reduced in the SMC layer of aortic aneurysms. Arhgap18 global knockout (Arhgap18(-/)(-)) mice exhibited a highly synthetic, proteolytic, and proinflammatory smooth muscle phenotype under basal conditions and when challenged with angiotensin II, developed TAA with increased frequency and severity compared with littermate controls. Chromatin immunoprecipitation studies revealed this phenotype is partly associated with strong enrichment of H3K4me3 and depletion of H3K27me3 at the MMP2 and TNF-α promoters in Arhgap18-deficient SMC. We further show that TAA formation in the Arhgap18(-/-) mice is associated with loss of Akt activation. The abnormal SMC phenotype observed in the Arhgap18(-/-) mice can be partially rescued by pharmacological treatment with the mTORC1 inhibitor rapamycin, which reduces the synthetic and proinflammatory phenotype of Arhgap18-deficient SMC.

CONCLUSION: We have identified ARHGAP18 as a novel protective gene against TAA formation and define an additional target for the future development of treatments to limit TAA pathogenesis.