Traversing the Learning Curve Associated with a New Minimal Access Aortic Valve Replacement Service.

OBJECTIVE: Isolated aortic valve replacement is a safe and frequently performed cardiac surgical procedure. Although minimal access approaches including right anterior thoracotomy and partial sternotomy have been adopted by some surgeons in recent years, concerns about additional procedural morbidity and mortality during the early phase of the learning curve persist. The aim of this study was to assess the impact of the learning curve on outcomes for a single surgeon implementing a new minimal access aortic valve replacement service. METHODS: Ninety-three patients undergoing minimal access aortic valve replacement performed by a single surgeon in our institution between October 2014 and March 2019 were analysed. Patients were divided into tertiles according to procedure order. Endpoints included peri-operative mortality and post-operative complications, and these were compared across tertiles to assess the impact of the learning curve on procedural outcomes. RESULTS: Overall in-hospital mortality was 2.15% (n=2). Despite significantly longer cardiopulmonary bypass and cross-clamp duration in the early tertile, there was no significant difference in the rate of post-operative complications, post-operative length of stay or in-hospital mortality between tertiles. CONCLUSIONS: Although our results have demonstrated a significant learning curve effect associated with the introduction of this minimally invasive approach to aortic valve replacement, as demonstrated by the significant reduction in cardiopulmonary bypass and cross-clamp duration over time, our findings suggest that a minimal access aortic valve replacement service can be safely commenced by an experienced surgeon without concerns about the learning curve significantly affecting post-operative morbidity and mortality.

A surprise aberrant pulmonary vein.

We report an incidental discovery of the superior pulmonary vein coming from a strange anatomical location when performing a robotic left lower lobectomy. When trying to identify the superior pulmonary vein, an aberrant pulmonary vein was found leading into the innominate vein.

Traversing the Learning Curve Associated with a New Minimal Access Aortic Valve Replacement Service

Abstract Objective: Isolated aortic valve replacement is a safe and frequently performed cardiac surgical procedure. Although minimal access approaches including right anterior thoracotomy and partial sternotomy have been adopted by some surgeons in recent years, concerns about additional procedural morbidity and mortality during the early phase of the learning curve persist. The aim of this study was to assess the impact of the learning curve on outcomes for a single surgeon implementing a new minimal access aortic valve replacement service. Methods: Ninety-three patients undergoing minimal access aortic valve replacement performed by a single surgeon in our institution between October 2014 and March 2019 were analysed. Patients were divided into tertiles according to procedure order. Endpoints included peri-operative mortality and post-operative complications, and these were compared across tertiles to assess the impact of the learning curve on procedural outcomes. Results: Overall in-hospital mortality was 2.15% (n=2). Despite significantly longer cardiopulmonary bypass and cross-clamp duration in the early tertile, there was no significant difference in the rate of post-operative complications, post-operative length of stay or in-hospital mortality between tertiles. Conclusions: Although our results have demonstrated a significant learning curve effect associated with the introduction of this minimally invasive approach to aortic valve replacement, as demonstrated by the significant reduction in cardiopulmonary bypass and cross-clamp duration over time, our findings suggest that a minimal access aortic valve replacement service can be safely commenced by an experienced surgeon without concerns about the learning curve significantly affecting post-operative morbidity and mortality.

Narasin, a novel antiviral compound that blocks dengue virus protein expression.

BACKGROUND: Dengue virus (DENV) is a mosquito-borne virus that causes a spectrum of human diseases ranging from mild dengue fever to dengue haemorrhagic fever and dengue shock syndrome in severe cases. Currently, there is no effective antiviral therapy or vaccine against DENV infection. METHODS: In order to identify potential antiviral agents against DENV, we performed high-throughput cell-based screening on a highly purified natural products library. Among the screening hits, selected compounds which displayed 50-75% inhibition against DENV2 were validated using secondary assays. Time-of-addition studies, dose-dependent assays, real time quantitative reverse transcriptase (RT)-PCR, Western blot and ultrastructural imaging were conducted in an attempt to elucidate the potential antiviral mechanisms of narasin. RESULTS: In this study, an ionophore, narasin was selected for detailed analysis due to its strong inhibitory profile against DENV infection with minimal cytotoxicity (50% cytotoxic concentration >1,000 µM). A dose-dependent study revealed narasin to have an 50% inhibitory concentration of less than 1 µM against all four serotypes of DENV. Time-of-addition studies of narasin-treated, DENV2-infected Huh-7 cells suggested narasin to be involved in inhibiting the post-entry stages of viral replication during DENV infection. Proteomic and ultrastructural analyses revealed the antiviral mechanism of narasin as likely to be associated with the disruption of viral protein synthesis. In addition, quantitative RT-PCR studies showed no differences in viral RNA levels between narasin-treated and control DENV2-infected cells. CONCLUSIONS: Narasin was identified and characterized as a novel agent that inhibits DENV replication in vitro through non-cytotoxic mechanisms, thus indicating its potential to be further developed as a therapeutic anti-DENV agent.