Journal Club #1 – Wednesday 17th January 2018 19:00 GMT.
Chair: Dr. Eoin O’Sullivan @Eoinrenal
One particularly interesting paper lately which has made some waves in the media was a French paper appearing in the Lancet, exploring the timing of cardiac surgery and outcomes. This was widely reported in the media on both sides of the Atlantic and to their credit, most broadsheets provided a balanced appraisal of the research. These articles don’t exist in a vacuum of course, and our patients will be reading their newspapers and perhaps wondering if all surgery should be performed in the afternoon? Perhaps they wonder why such an idea was even considered, let alone researched in such depth. I certainly did.
The Lancet (@thelancet) generously made our journal club’s paper open-access from 15-17th of January to allow everyone interested in joining the journal club to participate. Thank you, Lancet!
Montaigne D. et al. Daytime variation of perioperative myocardial injury in cardiac surgery and its prevention by Rev-Erba antagonism: a single-centre propensity-matched cohort study and a randomised study. The Lancet, 391(10115), 59-69.
Context and background to the paper
Some doctors love dashing around on ward rounds at 0530, and yet no amount of coffee can force me to function before 0800. “Some people are just morning people,” I tell myself. But it’s possible that they have different circadian rhythms. Enter Chronobiology, the fascinating discipline of biology that explore rhythms and timing of processes in our bodies and our cells. Chronobiology informs the fundamental question behind this paper, which is quite timely (pun intended) as this year’s Nobel Prize in Medicine was awarded to Jeffrey C. Hall, Michael Rosbash and Michael W. Young "for their discoveries of molecular mechanisms controlling the circadian rhythm."
It’s been noted in observational studies that there is a higher incidence of ST-Elevation Myocardial Infaractions (STEMIs) in the morning, and suggested the infarct size of morning STEMIs can be larger. Many, including Montaigne et al. have wondered whether some intrinsic vulnerability of the cardiac myoctyes in the morning, driven by the circadian rhythm, is responsible for this observation. To better understand this, the authors first formed a hypothesis, namely – that cardiac myocyte vulnerability leads to increased damage when insults occur at the specific phases of the circadian rhythm. The cardiac insult they chose to investigate was on-pump cardiac surgery for scheduled aortic replacement, but the principle of circadian vulnerability I think has potentially far reaching consequences in all our practices.
This paper is ambitiously expansive, and includes a small randomized trial component, a larger cohort study and some animal and in-vitro work to support the hypothesis. Its good practice to probe a question from different angles with complementary experiments, add some mechanistic validity to findings, which the authors have endeavoured to do.
The Journal Club on Wednesday 17th January, mainly focused on the methodology and results of the cohort study and randomized controlled trial, and discussed some of the strengths and limitations, and how we assimilate such a study into our broader understanding of medicine and clinical practice. We discussed how the authors ran their trial – what they did well, and where limitations lay. This helped us discuss the results and begin to understand them, and reflect on whether the study allows us to extrapolate anything to our own practice. We discussed what the next step should be for research in the area, what take home messages there are, and asked 'what would we tell our patients if they asked us about the timing of their surgery?'