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Journal Club 21/7/2020
Quote from Scalpel on 19th July 2020, 5:13 pmHello everyone! Welcome to this evening’s Journal Club with tutor Dr Kirolos Michael.
The article for the week will be released at 18:00 on our Journal Club Facebook event. This gives you 25 minutes to analyse the paper mimicking the time given for AFP interviews. We will then begin promptly at 18:30 for our discussion which will take place on our online chatroom.
Link to Journal Club event page:https://www.facebook.com/events/284941986049616
Link to this evenings chat room: Journal Club Discussion
Hello everyone! Welcome to this evening’s Journal Club with tutor Dr Kirolos Michael.
The article for the week will be released at 18:00 on our Journal Club Facebook event. This gives you 25 minutes to analyse the paper mimicking the time given for AFP interviews. We will then begin promptly at 18:30 for our discussion which will take place on our online chatroom.
Link to Journal Club event page:https://www.facebook.com/events/284941986049616
Link to this evenings chat room: Journal Club Discussion
Quote from Scalpel on 3rd August 2020, 10:30 pm
Daniel Ahari
Jul 21 / 6:29 pmHi Hello HellooLily Helston
Jul 21 / 6:30 pmHi all HelloKirolos Michael
Jul 21 / 6:30 pmHello everyone, Kirolos here. I’ll be you’re tutor todayAlexandra Brooks
Jul 21 / 6:30 pmhello Hi Hi allRox M
Jul 21 / 6:30 pmhi hello! Hi everyone! Can you please let us know your year of study and email addresses 🙂 Year of study going into or just completed? Final year – pvinchenzo01@qub.ac.uk Hi, becca.vitarana@gmail.com, going into year 4 roosindu@gmail.com Ill be going into my 4th year HelloLily Helston
Jul 21 / 6:31 pmolivia.helston@student.manchester.ac.uk, heading into 4th year graeme.burt@student.manchester.ac.uk going into final yearAlexandra Brooks
Jul 21 / 6:31 pmalexandra.brooks@student.manchester.ac.uk, going into 5th yearCameron Lynch
Jul 21 / 6:32 pmFinal year. cameron.lynch@student.manchester.ac.ukCallum Docherty
Jul 21 / 6:32 pmHi! Year 5 callum.docherty@student.manchester.ac.ukDaniel Ahari
Jul 21 / 6:32 pmdaniel.ahari@student.manchester.ac.uk just finished 4th year, intercalating nowRox M
Jul 21 / 6:32 pmroxana.moscalu@student.manchester.ac.uk, final year 180000142@aston.ac.uk going into 3rd yearKishan Pankhania
Jul 21 / 6:32 pmkishan.pankhania-2@student.manchester.ac.uk, final year going into 4th year, muhammad.hussain-9@student.manchester.ac.uk ali.tariq-4@postgrad.manchester.ac.uk, final year Thanks everyone! Before Kirolos takes over for this weeks discussion, just wanted to let you know if anyone has any suggestions at all for these sessions feel free to message me on Facebook, I quite actively post in the events and the AFP group. Kirolos hasn’t got time to offer specific AFP advice but he’s just going to go through analysis skills and queations they are likely to crop up! Hope this is alrightAnnabel Chadwick
Jul 21 / 6:33 pmannabel.chadwick@student.manchester.ac.uk, fifth yearShamia C
Jul 21 / 6:34 pmshamia.chowdhury@student.manchester.ac.uk going into intercalation having finished year 4Hassaan Ahmed
Jul 21 / 6:34 pmhassaan.ahmed@student.manchester.ac.uk going into 5th yearKirolos Michael
Jul 21 / 6:34 pmThanks Beth. Welcome everyone who’s joined us before & to anyone who is newNosa Uwadiae
Jul 21 / 6:35 pmnosa.uwadiae@student.manchester.ac.uk Going into finals.Kirolos Michael
Jul 21 / 6:35 pmToday’s theme is vascular surgery. I picked this article as it’s quite short & concise so should have been plenty of time to read throughKirolos Michael
Jul 21 / 6:36 pmSo can somebody describe what this study was looking at?Daniel Ahari
Jul 21 / 6:37 pmmortality and morbidity for TEVAR and open approaches to thoracic aorta surgery in End stage renal disease patients Evaluate the outcomes of open and endovascular descending thoracic aortic repair in dialysis-dependent patientsAlexandra Brooks
Jul 21 / 6:37 pmit was looking at the postoperative and long term outcomes of open vs. endovascular repair of descending aorta pathology in ESRD patients dependent on dialysisKirolos Michael
Jul 21 / 6:37 pmGreatKirolos Michael
Jul 21 / 6:37 pmEveryone clear on what TEVAR is? YesDaniel Ahari
Jul 21 / 6:38 pmassuming it’s just thoracic EVAR haha (endovascular aortic repair) Yes – Thoracic Endovascular Aortic RepairKirolos Michael
Jul 21 / 6:39 pmSo as you guys mentioned, it was to compare open thoracic aorta repair vs. thoracic endovascular aortic repair (TEVAR) which is a non-invasive technique. Its the equivalent of an EVAR, but for the thoracic aortaKirolos Michael
Jul 21 / 6:40 pmA little background, patients with renal impairment are a particular problem in vascular surgery. They tend to be very high risk, especially those on dialysis. TEVAR is often used in higher risk patients, hence why this study was comparing both techniques in an already high risk groupKirolos Michael
Jul 21 / 6:40 pmWhat was the study design?Daniel Ahari
Jul 21 / 6:40 pmretrospective cohort? retrospective cohort study As in a retrospective cohort study?Callum Docherty
Jul 21 / 6:40 pmRetrospective cohort Retrospective cohort studyKirolos Michael
Jul 21 / 6:41 pmI want to see everyone contributing today especially those who haven’t in the pastKirolos Michael
Jul 21 / 6:41 pmDoes anybody think anything other than cohort study? Based on last time I feel this was the same design…but I could be very wrong!Kirolos Michael
Jul 21 / 6:41 pmThose who think its cohort, can you briefly explain why that is?Kirolos Michael
Jul 21 / 6:42 pmThat’s right Trish, it’s a very similar design to the last paper comparing two methods (open and TEVAR) and measuring the outcome (morbidity and mortality)?Callum Docherty
Jul 21 / 6:42 pmIt’s a longitudinal study looking at an exposure of interest (in this case open or TEVAR repair)Rox M
Jul 21 / 6:42 pmbecause 2 groups are being compared…mainly. TEVAR and openShamia C
Jul 21 / 6:42 pmI agree with Trisha and cohort because of the large group size and because comparisons are made between two groups in this study It’s looking at a specific population set by defined limitations over a longitudinal period, retrospectively they select a bunch of people who have the condition and record their response ? it is comparing individuals that had TEVAR and open retrospectively or* they compared pre-existing haemodialysis patients who underwent open/TEVAR vs a control group (who werent dependent on dialysis before the approachesKirolos Michael
Jul 21 / 6:44 pmThat’s right. It is a cohort study. You have 2 groups of patient with 2 different exposures (i.e. one group were open surgery and the other group was the TEVAR group), you then compare them in terms of different outcome, hence it’s a cohortKirolos Michael
Jul 21 / 6:45 pmYou’ll find in surgery, a lot of the studies are observational, and often cohort, just because of difficulties & ethical dilemmas with doing things like blinded studies or RCTs etc.Kirolos Michael
Jul 21 / 6:45 pmWhat was the population of interest in this study? patients with ESRD Haemodialysis patients in the US Individuals who have ESRD who are on dialysisLily Helston
Jul 21 / 6:45 pmPatients who had preexisting ESRD on HDGeorgia Savvides
Jul 21 / 6:45 pmpatients with end stage renal disease on dialysisAlexandra Brooks
Jul 21 / 6:46 pmESRD patients dependant on dialysis with thoracic or thoracoabdominal aortic pathology Males with ESRD on dialysis that only had thoracic aneurysmsKirolos Michael
Jul 21 / 6:46 pmFantastic. So not just end stage renal disease (ESRD) patients, but those who are on haemodialysis Patients who underwent either TEVAR or open repair of the descending aorta who were on renal dialysis prior to their operationCallum Docherty
Jul 21 / 6:46 pmPatients with ESRD requiring haemomdialysis pre-intervention with any uniquely thoracic aortic pathology (i.e. no other artery) undergoing repair Not just males I think but majority were also particularly descending thoracic aortic repairKirolos Michael
Jul 21 / 6:47 pmNadin, is it only males & is it only just paitents with aneurysms or did they include other pathologies like dissection? haemodialysis patients with ESRDKirolos Michael
Jul 21 / 6:48 pmSo they were looking at different pathologies of the descending aorta (thoracic aneurysms, thoracocabdominal aneurysms & aortic dissections)Kirolos Michael
Jul 21 / 6:48 pmWere they looking at emergency cases or elective cases or both? The subgroup analysis excluded dissection but yes the overall analysis included aortic dissection 64% were maleCallum Docherty
Jul 21 / 6:48 pmBoth BothAlexandra Brooks
Jul 21 / 6:48 pmbothLily Helston
Jul 21 / 6:48 pmBoth the rest were female bothRox M
Jul 21 / 6:48 pmboth bothKirolos Michael
Jul 21 / 6:49 pmThat’s right Nadin, so they split off the pathologies in their analysis Both BothKirolos Michael
Jul 21 / 6:49 pmThat’s correct everyone. Good spot because it wasn’t initially very clear but they looked at both elective repairs & emergency ruptures (very different settings)Kirolos Michael
Jul 21 / 6:50 pmRight, shall we summarise the resultsKirolos Michael
Jul 21 / 6:50 pmStarting with the demographics, were there any differences in the demographics between the TEVAR & open surgery groups that were significant?Kirolos Michael
Jul 21 / 6:50 pmTable IIRox M
Jul 21 / 6:51 pmthe age of patients in tevar group was significantly higher than open surgery most of those who had TEVAR were older than those who had the open repairAlexandra Brooks
Jul 21 / 6:51 pmthe TEVAR subjects were older than the open repair patients Age the age gap and PAD?Lily Helston
Jul 21 / 6:51 pmage would be significant given the p valueHassaan Ahmed
Jul 21 / 6:51 pmOlder patients with tevar influences 1 year mortalityCallum Docherty
Jul 21 / 6:51 pmTEVAR patients were significantly older (TEVAR older) TEVAR were olderKirolos Michael
Jul 21 / 6:51 pmGreatKirolos Michael
Jul 21 / 6:51 pmSo as Akshara mentioned, there was a difference in nterms of peripheral arterial diseaseKirolos Michael
Jul 21 / 6:52 pmHowever, as Lily highlighted, only age was stastically significantKirolos Michael
Jul 21 / 6:52 pmOkay, moving on to other variables such as mortalityKirolos Michael
Jul 21 / 6:53 pm& 30 day complications the TEVAR group had a significantly lower rate of 30 day complications but they had a higher rate for strokesRox M
Jul 21 / 6:54 pmbut a hifger rate for stroke in tevarRox M
Jul 21 / 6:54 pmhigherAlexandra Brooks
Jul 21 / 6:54 pmTEVAR had a lower 30 day mortality than open but by 1 year the mortality between the two options was no different The Kaplan Myer shows lower early mortality in OPEN but by just under 4 years the overall mortality rates were similar (fig 2)Kirolos Michael
Jul 21 / 6:54 pmGood spot. Was this higher rate of stroke stastically significant? noKirolos Michael
Jul 21 / 6:55 pmwhat was the p-value Akshara? pneumonia, rest failure and stroke all p<0.05 resp*Kirolos Michael
Jul 21 / 6:55 pmI agree Graeme with the Kaplan Myer curve oh my apologies the p value is 0.018 so it would be statistically different?Kirolos Michael
Jul 21 / 6:56 pmSo TEVAR had reduced rates of pneumonia & respiratory failure, but higher rate of stroke (all statistically significant)Kirolos Michael
Jul 21 / 6:57 pmThere was no statistically significant difference in the rats of ileus, sepsis & paraplegia (because the p values were > 0.05)Kirolos Michael
Jul 21 / 6:57 pmand the 1 year mortality rate as Alexandra mentioned was no different between the 2 groupsKirolos Michael
Jul 21 / 6:58 pmEveryone happy with that? These are the main results. They dive further into regression analysis of factors implicated in mortality & they undertake sub-group analysis of different pathologies, but if everyone is happy, we can move on to strengths & weaknesses Sounds gooood Yes I agree. Yes YesKirolos Michael
Jul 21 / 6:59 pm* the only other thing to add is that TEVAR was associated with a better 30-day mortality (in the regression analysis & this was statistically significant)Rox M
Jul 21 / 7:00 pmyesKirolos Michael
Jul 21 / 7:00 pmWhat are the strengths of this study? Kirolos Michael, just to clarify – how does the Kaplan Meyer. curve show thisKirolos Michael
Jul 21 / 7:01 pmSo the Kaplan Meyer (survival curve) does not show that TEVAR has better 30 day mortality the fact that the overall survival rate didnt chnage by intervention type after a year so since P=0.4 for that comparison, there is no significant difference?Kirolos Michael
Jul 21 / 7:02 pmIts the regression analysis that suggests (when you factor in every other factor) that having a TEVAR had better 30 day mortality. the odds ration was o.41 oh okayKirolos Michael
Jul 21 / 7:03 pmHowever, the Kaplan meyer survival analysis was not significant & in fact showed as you said there was no statistically significant difference between the 2Kirolos Michael
Jul 21 / 7:03 pmSo they are analysing essentially the same thing in several different ways that makes sense, Thankyou! was confused for a min thereKirolos Michael
Jul 21 / 7:03 pmIt is a little confusing because they’ve analysed things in multiple waysKirolos Michael
Jul 21 / 7:03 pmAny strengths or weaknesses?Daniel Ahari
Jul 21 / 7:04 pmStrength: similar demographics between the two groups (besides age) which makes comparison more accurate I don’t understand why they looked at data from 2005-2008 when the study was presented in 2016. why couldn’t they use more recent data? Found it strange that they included trauma patients as their were so few and trauma was non-specific and so could potentially have many different outcomes for patients Data taken from 2005–08? I did think this tooKirolos Michael
Jul 21 / 7:05 pmAll very good pointsLily Helston
Jul 21 / 7:05 pmWould a weakness be that its a nationwide analyses? – as it is harder to minimise bias accounting for different surgeons/ after care of the centre etc In terms of weaknesses – I find it much easier to read studies which incorporate their tables within the text itself.Callum Docherty
Jul 21 / 7:05 pmI like how they framed their results with the discussion/conclusions – I think they were quite modest and make it clear there were a number of limitations to the study Also they used a national bank this time rather than one centre like in the last paper so i thought this would me more generalisable to the population?Kirolos Michael
Jul 21 / 7:06 pmI’m also intrigued by the wide variety of pathologies. Elective & emergency. And inclusion of traumas tooLily Helston
Jul 21 / 7:06 pm^ but also like trish said, it could be a strengthKirolos Michael
Jul 21 / 7:06 pmFanatastic comments everyoneKirolos Michael
Jul 21 / 7:06 pmin their defence, they have been very modest about their claimsCallum Docherty
Jul 21 / 7:06 pmOne big problem I think is their Cox regression shows increasing age is associated with significantly increased mortality over time, but the TEVAR group was significantly older on average compared to the open groupKirolos Michael
Jul 21 / 7:06 pmeven the title I found interesting Yes Lily, I feel you it can be used either way as now its not just the same surgeonKirolos Michael
Jul 21 / 7:07 pmVery good point Callum. So TEVAR was essentially reserved for the patients who were already at increased risk anyway Why is the title interesting?Kirolos Michael
Jul 21 / 7:07 pmI mean the title is interesting because the already admit that both treatments are already high mortality I seeKirolos Michael
Jul 21 / 7:08 pmso they’re not trying to sell TEVAR as a low-complication rate alterantive etc. excluded those who had concomitant arch, root, or ascending aortic repair – no idea what effect this hasKirolos Michael
Jul 21 / 7:08 pmWhich I respect. They could have tried to spin this article as TEVAR being much better in terms of short term complicationsKirolos Michael
Jul 21 / 7:09 pmSo Trish, they excluded them because these factors make surgery more complicated and the pathologies themselves have different morbidity & mortality rates associated with themKirolos Michael
Jul 21 / 7:09 pmThey tried to focus on pathologies of the descending aorta ONLYKirolos Michael
Jul 21 / 7:10 pmand avoided pathologies that involve the root of the aorta (close to the heart) & arch which would have resulted in more confounding factorsKirolos Michael
Jul 21 / 7:10 pmAny other comments? Thank you, Kirolos can you please explain about the data being used from 2008? Is this a weakness or something that cant be avoidedShamia C
Jul 21 / 7:10 pmHow would using older data be seen as a weakness?Callum Docherty
Jul 21 / 7:10 pmAs has been pointed out I definitely think data taken from 2005-2008 is a bit odd – endovascular surgery seems like a rapidly evolving field and presumably skill and technique has changed since 10+ years agoKirolos Michael
Jul 21 / 7:11 pmI totally agree with you on the outdated dataKirolos Michael
Jul 21 / 7:11 pmthey only followed patietns up for max 4 years in the Kaplan-Meyer analysis Also is this study better as they did 1 year follow up? compared to just 30 days?Kirolos Michael
Jul 21 / 7:11 pmTEVAR has come a long way since 2005 etcKirolos Michael
Jul 21 / 7:11 pmSo yes, definitely the longer follow up, the betterKirolos Michael
Jul 21 / 7:12 pmAs you guys might have noticed, when I pick these papers, I pick ones with a lot of holes in their methodologies that make for more interesting critiquesKirolos Michael
Jul 21 / 7:12 pmVery strong studies are much harder to rip apartKirolos Michael
Jul 21 / 7:12 pmAny other comments, thoughts or questions?Kirolos Michael
Jul 21 / 7:13 pmOr shall we wrap up? They didn’t specify cause of renal pathology. I assume vascular causes of renal diseases will affect outcomes Also I’ve realised having read the other paper from last time you can compare it to that and it makes it easier! maybe I will get the hang of it in 10 weeks time!! Thank you! ive a question regarding the cox regression that was mentioned in a previous commentKirolos Michael
Jul 21 / 7:14 pmVery true Graeme. Although in general as well dialysis is generally associated with adverse cardiovascular outcomes overall anywayKirolos Michael
Jul 21 / 7:14 pmFire away Roosindu why is the cox regression used here to show increasing age being associated with higher mortality like does it make the claim more valid?Kirolos Michael
Jul 21 / 7:15 pmSo cox regression is a form of analysis which looks at all the different factors and teases which ones impacted the outcome & by how muchKirolos Michael
Jul 21 / 7:15 pmThey included age, because it’s a really important factor & it’s assumed to increase risk anyway so this further demonstrates thisShamia C
Jul 21 / 7:15 pmI wonder if they have used outdated data as in Figure 1 there appears to be a general trend of greater number of endovascular vs open interventions with each year, thus would it make it more difficult to accurately compare the outcomes of the interventions? Oh I see that makes senseKirolos Michael
Jul 21 / 7:16 pmbut then TEVAR patients were older, but in cox regression had better 30 day mortality, yet age suggests worse outcomesKirolos Michael
Jul 21 / 7:16 pmso they’re trying to say, these TEVAR pateints should have had much worse outcomes just because of the age alone, but the outcome ended up being the same anyway. That’s I read into itKirolos Michael
Jul 21 / 7:17 pmVery fair point Shamia. I don’t know if they just had the data lying around That makes a lot of senseKirolos Michael
Jul 21 / 7:17 pmRightKirolos Michael
Jul 21 / 7:17 pmThanks for attending guys. I’ll be grateful if you could fill in this quick feedback form: https://forms.gle/nAHa4tqG4Rv9yNZj6Kirolos Michael
Jul 21 / 7:17 pmNext session’s theme will be neurosurgeryShamia C
Jul 21 / 7:17 pmThank you! Thanks, bye!Kirolos Michael
Jul 21 / 7:17 pmfeel free to email me any suggests for articles at kirolosmichael@gmail.com Thanks 🙂Kirolos Michael
Jul 21 / 7:18 pmand feel free to email any questions we didn’t cover Thank youKirolos Michael
Jul 21 / 7:18 pmThanks guysAlexandra Brooks
Jul 21 / 7:18 pmthank you! Thanks!Daniel Ahari
Jul 21 / 7:18 pmThanks! Thanks Kirolos !Callum Docherty
Jul 21 / 7:18 pmThanks! Thank you! Thanks Kirolos!Rox M
Jul 21 / 7:18 pmthank youLily Helston
Jul 21 / 7:19 pmThanks once again !Georgia Savvides
Jul 21 / 7:19 pmthank you!Kishan Pankhania
Jul 21 / 7:19 pmThanks Replythanks
Daniel Ahari Jul 21 / 6:29 pm
Hi
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Hello
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Helloo
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Lily Helston Jul 21 / 6:30 pm
Hi all
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Hello
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Kirolos Michael Jul 21 / 6:30 pm
Hello everyone, Kirolos here. I’ll be you’re tutor today
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Alexandra Brooks Jul 21 / 6:30 pm
hello
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Hi
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Hi all
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Rox M Jul 21 / 6:30 pm
hi
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hello!
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Hi everyone!
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Can you please let us know your year of study and email addresses 🙂
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Year of study going into or just completed?
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Final year – pvinchenzo01@qub.ac.uk
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Hi, becca.vitarana@gmail.com, going into year 4
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roosindu@gmail.com Ill be going into my 4th year
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Hello
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Lily Helston Jul 21 / 6:31 pm
olivia.helston@student.manchester.ac.uk, heading into 4th year
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graeme.burt@student.manchester.ac.uk going into final year
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Alexandra Brooks Jul 21 / 6:31 pm
alexandra.brooks@student.manchester.ac.uk, going into 5th year
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Cameron Lynch Jul 21 / 6:32 pm
Final year. cameron.lynch@student.manchester.ac.uk
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Callum Docherty Jul 21 / 6:32 pm
Hi! Year 5 callum.docherty@student.manchester.ac.uk
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Daniel Ahari Jul 21 / 6:32 pm
daniel.ahari@student.manchester.ac.uk just finished 4th year, intercalating now
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Rox M Jul 21 / 6:32 pm
roxana.moscalu@student.manchester.ac.uk, final year
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180000142@aston.ac.uk going into 3rd year
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Kishan Pankhania Jul 21 / 6:32 pm
kishan.pankhania-2@student.manchester.ac.uk, final year
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going into 4th year, muhammad.hussain-9@student.manchester.ac.uk
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ali.tariq-4@postgrad.manchester.ac.uk, final year
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Thanks everyone! Before Kirolos takes over for this weeks discussion, just wanted to let you know if anyone has any suggestions at all for these sessions feel free to message me on Facebook, I quite actively post in the events and the AFP group. Kirolos hasn’t got time to offer specific AFP advice but he’s just going to go through analysis skills and queations they are likely to crop up! Hope this is alright
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Annabel Chadwick Jul 21 / 6:33 pm
annabel.chadwick@student.manchester.ac.uk, fifth year
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Shamia C Jul 21 / 6:34 pm
shamia.chowdhury@student.manchester.ac.uk going into intercalation having finished year 4
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Hassaan Ahmed Jul 21 / 6:34 pm
hassaan.ahmed@student.manchester.ac.uk going into 5th year
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Kirolos Michael Jul 21 / 6:34 pm
Thanks Beth. Welcome everyone who’s joined us before & to anyone who is new
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Nosa Uwadiae Jul 21 / 6:35 pm
nosa.uwadiae@student.manchester.ac.uk Going into finals.
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Kirolos Michael Jul 21 / 6:35 pm
Today’s theme is vascular surgery. I picked this article as it’s quite short & concise so should have been plenty of time to read through
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Kirolos Michael Jul 21 / 6:36 pm
So can somebody describe what this study was looking at?
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Daniel Ahari Jul 21 / 6:37 pm
mortality and morbidity for TEVAR and open approaches to thoracic aorta surgery in End stage renal disease patients
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Evaluate the outcomes of open and endovascular descending thoracic aortic repair in dialysis-dependent patients
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Alexandra Brooks Jul 21 / 6:37 pm
it was looking at the postoperative and long term outcomes of open vs. endovascular repair of descending aorta pathology in ESRD patients dependent on dialysis
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Kirolos Michael Jul 21 / 6:37 pm
Great
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Kirolos Michael Jul 21 / 6:37 pm
Everyone clear on what TEVAR is?
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Yes
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Daniel Ahari Jul 21 / 6:38 pm
assuming it’s just thoracic EVAR haha (endovascular aortic repair)
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Yes – Thoracic Endovascular Aortic Repair
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Kirolos Michael Jul 21 / 6:39 pm
So as you guys mentioned, it was to compare open thoracic aorta repair vs. thoracic endovascular aortic repair (TEVAR) which is a non-invasive technique. Its the equivalent of an EVAR, but for the thoracic aorta
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Kirolos Michael Jul 21 / 6:40 pm
A little background, patients with renal impairment are a particular problem in vascular surgery. They tend to be very high risk, especially those on dialysis. TEVAR is often used in higher risk patients, hence why this study was comparing both techniques in an already high risk group
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Kirolos Michael Jul 21 / 6:40 pm
What was the study design?
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Daniel Ahari Jul 21 / 6:40 pm
retrospective cohort?
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retrospective cohort study
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As in a retrospective cohort study?
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Callum Docherty Jul 21 / 6:40 pm
Retrospective cohort
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Retrospective cohort study
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Kirolos Michael Jul 21 / 6:41 pm
I want to see everyone contributing today especially those who haven’t in the past
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Kirolos Michael Jul 21 / 6:41 pm
Does anybody think anything other than cohort study?
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Based on last time I feel this was the same design…but I could be very wrong!
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Kirolos Michael Jul 21 / 6:41 pm
Those who think its cohort, can you briefly explain why that is?
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Kirolos Michael Jul 21 / 6:42 pm
That’s right Trish, it’s a very similar design to the last paper
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comparing two methods (open and TEVAR) and measuring the outcome (morbidity and mortality)?
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Callum Docherty Jul 21 / 6:42 pm
It’s a longitudinal study looking at an exposure of interest (in this case open or TEVAR repair)
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Rox M Jul 21 / 6:42 pm
because 2 groups are being compared…mainly. TEVAR and open
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Shamia C Jul 21 / 6:42 pm
I agree with Trisha and cohort because of the large group size and because comparisons are made between two groups in this study
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It’s looking at a specific population set by defined limitations over a longitudinal period, retrospectively
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they select a bunch of people who have the condition and record their response ?
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it is comparing individuals that had TEVAR and open retrospectively
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or*
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they compared pre-existing haemodialysis patients who underwent open/TEVAR vs a control group (who werent dependent on dialysis before the approaches
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Kirolos Michael Jul 21 / 6:44 pm
That’s right. It is a cohort study. You have 2 groups of patient with 2 different exposures (i.e. one group were open surgery and the other group was the TEVAR group), you then compare them in terms of different outcome, hence it’s a cohort
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Kirolos Michael Jul 21 / 6:45 pm
You’ll find in surgery, a lot of the studies are observational, and often cohort, just because of difficulties & ethical dilemmas with doing things like blinded studies or RCTs etc.
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Kirolos Michael Jul 21 / 6:45 pm
What was the population of interest in this study?
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patients with ESRD
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Haemodialysis patients in the US
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Individuals who have ESRD who are on dialysis
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Lily Helston Jul 21 / 6:45 pm
Patients who had preexisting ESRD on HD
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Georgia Savvides Jul 21 / 6:45 pm
patients with end stage renal disease on dialysis
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Alexandra Brooks Jul 21 / 6:46 pm
ESRD patients dependant on dialysis with thoracic or thoracoabdominal aortic pathology
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Males with ESRD on dialysis that only had thoracic aneurysms
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Kirolos Michael Jul 21 / 6:46 pm
Fantastic. So not just end stage renal disease (ESRD) patients, but those who are on haemodialysis
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Patients who underwent either TEVAR or open repair of the descending aorta who were on renal dialysis prior to their operation
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Callum Docherty Jul 21 / 6:46 pm
Patients with ESRD requiring haemomdialysis pre-intervention with any uniquely thoracic aortic pathology (i.e. no other artery) undergoing repair
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Not just males I think but majority were
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also particularly descending thoracic aortic repair
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Kirolos Michael Jul 21 / 6:47 pm
Nadin, is it only males & is it only just paitents with aneurysms or did they include other pathologies like dissection?
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haemodialysis patients with ESRD
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Kirolos Michael Jul 21 / 6:48 pm
So they were looking at different pathologies of the descending aorta (thoracic aneurysms, thoracocabdominal aneurysms & aortic dissections)
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Kirolos Michael Jul 21 / 6:48 pm
Were they looking at emergency cases or elective cases or both?
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The subgroup analysis excluded dissection but yes the overall analysis included aortic dissection
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64% were male
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Callum Docherty Jul 21 / 6:48 pm
Both
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Both
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Alexandra Brooks Jul 21 / 6:48 pm
both
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Lily Helston Jul 21 / 6:48 pm
Both
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the rest were female
|
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both
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Rox M Jul 21 / 6:48 pm
both
|
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both
|
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Kirolos Michael Jul 21 / 6:49 pm
That’s right Nadin, so they split off the pathologies in their analysis
|
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Both
|
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Both
|
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Kirolos Michael Jul 21 / 6:49 pm
That’s correct everyone. Good spot because it wasn’t initially very clear but they looked at both elective repairs & emergency ruptures (very different settings)
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Kirolos Michael Jul 21 / 6:50 pm
Right, shall we summarise the results
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Kirolos Michael Jul 21 / 6:50 pm
Starting with the demographics, were there any differences in the demographics between the TEVAR & open surgery groups that were significant?
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Kirolos Michael Jul 21 / 6:50 pm
Table II
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Rox M Jul 21 / 6:51 pm
the age of patients in tevar group was significantly higher than open surgery
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most of those who had TEVAR were older than those who had the open repair
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Alexandra Brooks Jul 21 / 6:51 pm
the TEVAR subjects were older than the open repair patients
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Age
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the age gap and PAD?
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Lily Helston Jul 21 / 6:51 pm
age would be significant given the p value
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Hassaan Ahmed Jul 21 / 6:51 pm
Older patients with tevar influences 1 year mortality
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Callum Docherty Jul 21 / 6:51 pm
TEVAR patients were significantly older
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(TEVAR older)
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TEVAR were older
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Kirolos Michael Jul 21 / 6:51 pm
Great
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Kirolos Michael Jul 21 / 6:51 pm
So as Akshara mentioned, there was a difference in nterms of peripheral arterial disease
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Kirolos Michael Jul 21 / 6:52 pm
However, as Lily highlighted, only age was stastically significant
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Kirolos Michael Jul 21 / 6:52 pm
Okay, moving on to other variables such as mortality
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Kirolos Michael Jul 21 / 6:53 pm
& 30 day complications
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the TEVAR group had a significantly lower rate of 30 day complications
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but they had a higher rate for strokes
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Rox M Jul 21 / 6:54 pm
but a hifger rate for stroke in tevar
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Rox M Jul 21 / 6:54 pm
higher
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Alexandra Brooks Jul 21 / 6:54 pm
TEVAR had a lower 30 day mortality than open but by 1 year the mortality between the two options was no different
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The Kaplan Myer shows lower early mortality in OPEN but by just under 4 years the overall mortality rates were similar (fig 2)
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Kirolos Michael Jul 21 / 6:54 pm
Good spot. Was this higher rate of stroke stastically significant?
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no
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Kirolos Michael Jul 21 / 6:55 pm
what was the p-value Akshara?
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pneumonia, rest failure and stroke all p<0.05
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resp*
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Kirolos Michael Jul 21 / 6:55 pm
I agree Graeme with the Kaplan Myer curve
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oh my apologies the p value is 0.018 so it would be statistically different?
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Kirolos Michael Jul 21 / 6:56 pm
So TEVAR had reduced rates of pneumonia & respiratory failure, but higher rate of stroke (all statistically significant)
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Kirolos Michael Jul 21 / 6:57 pm
There was no statistically significant difference in the rats of ileus, sepsis & paraplegia (because the p values were > 0.05)
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Kirolos Michael Jul 21 / 6:57 pm
and the 1 year mortality rate as Alexandra mentioned was no different between the 2 groups
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Kirolos Michael Jul 21 / 6:58 pm
Everyone happy with that? These are the main results. They dive further into regression analysis of factors implicated in mortality & they undertake sub-group analysis of different pathologies, but if everyone is happy, we can move on to strengths & weaknesses
|
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Sounds gooood
|
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Yes I agree.
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Yes
|
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Yes
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Kirolos Michael Jul 21 / 6:59 pm
* the only other thing to add is that TEVAR was associated with a better 30-day mortality (in the regression analysis & this was statistically significant)
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Rox M Jul 21 / 7:00 pm
yes
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Kirolos Michael Jul 21 / 7:00 pm
What are the strengths of this study?
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Kirolos Michael, just to clarify – how does the Kaplan Meyer. curve show this
|
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Kirolos Michael Jul 21 / 7:01 pm
So the Kaplan Meyer (survival curve) does not show that TEVAR has better 30 day mortality
|
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the fact that the overall survival rate didnt chnage by intervention type after a year
|
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so since P=0.4 for that comparison, there is no significant difference?
|
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Kirolos Michael Jul 21 / 7:02 pm
Its the regression analysis that suggests (when you factor in every other factor) that having a TEVAR had better 30 day mortality. the odds ration was o.41
|
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oh okay
|
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Kirolos Michael Jul 21 / 7:03 pm
However, the Kaplan meyer survival analysis was not significant & in fact showed as you said there was no statistically significant difference between the 2
|
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Kirolos Michael Jul 21 / 7:03 pm
So they are analysing essentially the same thing in several different ways
|
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that makes sense, Thankyou! was confused for a min there
|
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Kirolos Michael Jul 21 / 7:03 pm
It is a little confusing because they’ve analysed things in multiple ways
|
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Kirolos Michael Jul 21 / 7:03 pm
Any strengths or weaknesses?
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Daniel Ahari Jul 21 / 7:04 pm
Strength: similar demographics between the two groups (besides age) which makes comparison more accurate
|
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I don’t understand why they looked at data from 2005-2008 when the study was presented in 2016. why couldn’t they use more recent data?
|
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Found it strange that they included trauma patients as their were so few and trauma was non-specific and so could potentially have many different outcomes for patients
|
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Data taken from 2005–08? I did think this too
|
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Kirolos Michael Jul 21 / 7:05 pm
All very good points
|
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Lily Helston Jul 21 / 7:05 pm
Would a weakness be that its a nationwide analyses? – as it is harder to minimise bias accounting for different surgeons/ after care of the centre etc
|
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In terms of weaknesses – I find it much easier to read studies which incorporate their tables within the text itself.
|
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Callum Docherty Jul 21 / 7:05 pm
I like how they framed their results with the discussion/conclusions – I think they were quite modest and make it clear there were a number of limitations to the study
|
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Also they used a national bank this time rather than one centre like in the last paper so i thought this would me more generalisable to the population?
|
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Kirolos Michael Jul 21 / 7:06 pm
I’m also intrigued by the wide variety of pathologies. Elective & emergency. And inclusion of traumas too
|
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Lily Helston Jul 21 / 7:06 pm
^ but also like trish said, it could be a strength
|
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Kirolos Michael Jul 21 / 7:06 pm
Fanatastic comments everyone
|
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Kirolos Michael Jul 21 / 7:06 pm
in their defence, they have been very modest about their claims
|
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Callum Docherty Jul 21 / 7:06 pm
One big problem I think is their Cox regression shows increasing age is associated with significantly increased mortality over time, but the TEVAR group was significantly older on average compared to the open group
|
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Kirolos Michael Jul 21 / 7:06 pm
even the title I found interesting
|
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Yes Lily, I feel you it can be used either way as now its not just the same surgeon
|
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Kirolos Michael Jul 21 / 7:07 pm
Very good point Callum. So TEVAR was essentially reserved for the patients who were already at increased risk anyway
|
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Why is the title interesting?
|
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Kirolos Michael Jul 21 / 7:07 pm
I mean the title is interesting because the already admit that both treatments are already high mortality
|
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I see
|
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Kirolos Michael Jul 21 / 7:08 pm
so they’re not trying to sell TEVAR as a low-complication rate alterantive etc.
|
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excluded those who had concomitant arch, root, or ascending aortic repair – no idea what effect this has
|
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Kirolos Michael Jul 21 / 7:08 pm
Which I respect. They could have tried to spin this article as TEVAR being much better in terms of short term complications
|
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Kirolos Michael Jul 21 / 7:09 pm
So Trish, they excluded them because these factors make surgery more complicated and the pathologies themselves have different morbidity & mortality rates associated with them
|
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Kirolos Michael Jul 21 / 7:09 pm
They tried to focus on pathologies of the descending aorta ONLY
|
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Kirolos Michael Jul 21 / 7:10 pm
and avoided pathologies that involve the root of the aorta (close to the heart) & arch which would have resulted in more confounding factors
|
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Kirolos Michael Jul 21 / 7:10 pm
Any other comments?
|
|||
Thank you, Kirolos can you please explain about the data being used from 2008? Is this a weakness or something that cant be avoided
|
|||
Shamia C Jul 21 / 7:10 pm
How would using older data be seen as a weakness?
|
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Callum Docherty Jul 21 / 7:10 pm
As has been pointed out I definitely think data taken from 2005-2008 is a bit odd – endovascular surgery seems like a rapidly evolving field and presumably skill and technique has changed since 10+ years ago
|
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Kirolos Michael Jul 21 / 7:11 pm
I totally agree with you on the outdated data
|
|||
Kirolos Michael Jul 21 / 7:11 pm
they only followed patietns up for max 4 years in the Kaplan-Meyer analysis
|
|||
Also is this study better as they did 1 year follow up? compared to just 30 days?
|
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Kirolos Michael Jul 21 / 7:11 pm
TEVAR has come a long way since 2005 etc
|
|||
Kirolos Michael Jul 21 / 7:11 pm
So yes, definitely the longer follow up, the better
|
|||
Kirolos Michael Jul 21 / 7:12 pm
As you guys might have noticed, when I pick these papers, I pick ones with a lot of holes in their methodologies that make for more interesting critiques
|
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Kirolos Michael Jul 21 / 7:12 pm
Very strong studies are much harder to rip apart
|
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Kirolos Michael Jul 21 / 7:12 pm
Any other comments, thoughts or questions?
|
|||
Kirolos Michael Jul 21 / 7:13 pm
Or shall we wrap up?
|
|||
They didn’t specify cause of renal pathology. I assume vascular causes of renal diseases will affect outcomes
|
|||
Also I’ve realised having read the other paper from last time you can compare it to that and it makes it easier! maybe I will get the hang of it in 10 weeks time!! Thank you!
|
|||
ive a question regarding the cox regression that was mentioned in a previous comment
|
|||
Kirolos Michael Jul 21 / 7:14 pm
Very true Graeme. Although in general as well dialysis is generally associated with adverse cardiovascular outcomes overall anyway
|
|||
Kirolos Michael Jul 21 / 7:14 pm
Fire away Roosindu
|
|||
why is the cox regression used here to show increasing age being associated with higher mortality
|
|||
like does it make the claim more valid?
|
|||
Kirolos Michael Jul 21 / 7:15 pm
So cox regression is a form of analysis which looks at all the different factors and teases which ones impacted the outcome & by how much
|
|||
Kirolos Michael Jul 21 / 7:15 pm
They included age, because it’s a really important factor & it’s assumed to increase risk anyway so this further demonstrates this
|
|||
Shamia C Jul 21 / 7:15 pm
I wonder if they have used outdated data as in Figure 1 there appears to be a general trend of greater number of endovascular vs open interventions with each year, thus would it make it more difficult to accurately compare the outcomes of the interventions?
|
|||
Oh I see that makes sense
|
|||
Kirolos Michael Jul 21 / 7:16 pm
but then TEVAR patients were older, but in cox regression had better 30 day mortality, yet age suggests worse outcomes
|
|||
Kirolos Michael Jul 21 / 7:16 pm
so they’re trying to say, these TEVAR pateints should have had much worse outcomes just because of the age alone, but the outcome ended up being the same anyway. That’s I read into it
|
|||
Kirolos Michael Jul 21 / 7:17 pm
Very fair point Shamia. I don’t know if they just had the data lying around
|
|||
That makes a lot of sense
|
|||
Kirolos Michael Jul 21 / 7:17 pm
Right
|
|||
Kirolos Michael Jul 21 / 7:17 pm
Thanks for attending guys. I’ll be grateful if you could fill in this quick feedback form: https://forms.gle/nAHa4tqG4Rv9yNZj6
|
|||
Kirolos Michael Jul 21 / 7:17 pm
Next session’s theme will be neurosurgery
|
|||
Shamia C Jul 21 / 7:17 pm
Thank you!
|
|||
Thanks, bye!
|
|||
Kirolos Michael Jul 21 / 7:17 pm
feel free to email me any suggests for articles at kirolosmichael@gmail.com
|
|||
Thanks 🙂
|
|||
Kirolos Michael Jul 21 / 7:18 pm
and feel free to email any questions we didn’t cover
|
|||
Thank you
|
|||
Kirolos Michael Jul 21 / 7:18 pm
Thanks guys
|
|||
Alexandra Brooks Jul 21 / 7:18 pm
thank you!
|
|||
Thanks!
|
|||
Daniel Ahari Jul 21 / 7:18 pm
Thanks!
|
|||
Thanks Kirolos !
|
|||
Callum Docherty Jul 21 / 7:18 pm
Thanks!
|
|||
Thank you!
|
|||
Thanks Kirolos!
|
|||
Rox M Jul 21 / 7:18 pm
thank you
|
|||
Lily Helston Jul 21 / 7:19 pm
Thanks once again !
|
|||
Georgia Savvides Jul 21 / 7:19 pm
thank you!
|
|||
Kishan Pankhania Jul 21 / 7:19 pm
Thanks
|
|||
Reply
thanks
|