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stroke risk in ASYMPTOMATIC Carotid plaques: time to use computarised imaging and risk analysis

03/17/2020

Identification of Patients with a Histologically Unstable Carotid Plaque Using Ultrasonic Plaque Image Analysis
















A total of 126 patients were included in the study. Based on the presence and extent of histological features including haemorrhage, thrombus, fibrous tissue, lipid core, inflammation, neovascularity, foam cells, and cap rupture, 39 plaques were graded as predominantly stable, while 87 were predominantly unstable. Unstable plaques were associated with a plaque area >95 mm2 (OR 4.15; 95% CI 1.34–12.8 p = .009), a juxtaluminal black area >6 mm2 (OR 2.77; 95% CI 1.24 to 6.17 p = .01) and a GSM <25 (OR 3.76; 95% CI 1.14–12.39). Logistic regression indicated that patients with the first two features had a 90% probability of having a histologically unstable plaque. The model was used to calculate the probability of having an unstable plaque in each patient. The receiver operating characteristic curve using the p value was 0.68 (95% CI 0.59–0.78).


Comments:
This is for me very relvant in asymptomatic patients, mainly to justify the operation; and hence the risk of giving a stroke. High risk plaques are DANGEROUS; it does correlate with thrombus in the plaque; but not with development of symptoms (notice this). 


Uncategorized

Final reflections on my beloved doctorate

03/17/2020



Introducing A New Diagnostic tool and Methodolgy for detecting outliers in aortic surgery early and reliably …
 
In summary, there are three points that probably explain the whole story: 

 

  • The medical tradition of checking performance has been in the form of audit-type method for ‘really’ long: get the notes; check your practice; compare to others; draw conclusions .. This has worked well in general; but has failed drastically in few occasions (Harold Shipman, Mid Staffordshorem, etc.) 
  • Industrial sector has revolutionised this approach over a decade ago: they moved into SPCs ..
  • I am introducing an original methodology whereby one can apply SPCs effectively as a diagnostic tool in aortic surgery; and hence improve quality significantly and in time… I will show how to do this .. and will test it immediately and show the effectiveness of such a tool. 
The basis of my research interests is a desire to improve the quality of monitoring outcome in aortic surgery using modern way of thinking. 
The process for achieving this is by: 
– first, identifying and understanding the problems faced by current policy makers in charge of monitoring aortic surgery outcome; 
– second, formulating effective ways of addressing these problems 
– thirdly evaluating the impact of these interventions;
– and finally, disseminating the data to enable policy change so that findings can be hard wired into clinical provision. 
 
See prof Banjerjee on addressing dementia, university of Sussex 
 
So in one sentence, my research question is: can vascular surgeons monitor and improve themselves better?
This project is probably bound together by one idea: is there a place for a new diagnostic test to detect outliers early and effectively in aortic surgery?
I was inspired by few things that really made me complete the project in full …  
  • I fall in love with Oxford .. since my 1st medical school year .. Oxford inspires me .. its art .. its colleges .. its busy scientific life .. and all the discussions running in there … 
  • Hence .. I connected to QRS team in Oxford extensively … to find out that they failed (recently and drastically at that time) in ‘knitting’ quality control methodologies (that we enjoyed talking and publishing about) into a proper tool … 
  • and I was lucky that I moved to Brighton … the lovely Brighton … the city that literally ‘knits’ everyone and everything together … and with an inspiring teacher at work, I proposed.. and they accepted my proposal … 

 

This topic has in fact attracted many issues and debates recently – 
  • For example, will vascular surgeons be required eventually to publish their outcome for public scrutiny like their counterpart cardiothoracic surgeon? The answer came few years ago: YES
  • What about all this variation in practices … how to control and improve such level of variation .. 
  • and what about the completeness and validity of NVD (now NVR)? 
  • what also will guarantee that we will not have another Harold Shipman or Mid Staffordshire drastic failing?  
 
The problem I am talking about does worth tackling … 
  • We have to learn from recent inquiries … monitoring outcome is simply one of the major recommendations for the latest £13-million mid-staffordshire inquiry … 
  • We need to knit our service together while centralisation takes place .. failing to monitor outcome and act rapidly can result in another Bristol Inquiry … 
  • and we need to learn from better business in the field of quality control … the industrial sectors has identified this and tackle it while ago … 
  • and finally … we have limited resources .. and we can not offered losing any extra penny in a poorly organised poorly monitored service/surgeon who are not delivering a quality service that fits the purpose … 
 

 

The team/person who had the strongest influence on the subject area I choose … is … Prof. Doug Altman and his team, Dr Gary Collins, at the Centre of Statistics in medicine, Oxford University .. Those guys are certainly exceptional … just google Doug Altman and see how much influence he has had on advancing statistics in the medical field .. and how much inventions he added to human knowledge … He, with the deep and inspiring discussions with Gary Collins and Peter mcCulloch, has certainly inspired me in full … 
Then it was only when I moved to Brighton when the influence of another thinker, Waquar yusuf, came into my life … and with all, I managed to knit my ideas together and start testing my hypothesis under the umbrella of the University … 
 
Which are the three most important papers that relate to your thesis?
  • the unpublished paper by Gary Collins .. SELECTING THE CONTROL LIMIT IN CUSUM MONITORING OF A PROPORTION USING FRACTIONAL POLYNOMIALS – Gary Collins et al .. 
  • Wald, 1945, on:  Sequential Tests of Statistical Hypotheses. 
  • Mohammed 2001: Bristol, Shipman, and clinical governance: Shewhart’s forgotten lessons
 
Any published work closest to me?
 

 

  • Yes and No … 
  • as a methodology (a rather thorough one) – I have not found any similar work/ideas in literature whatsoever … 
  • but as using CUSUM for monitoring … few are there … Chen: on EMS system .. 
 
What about the history in relation to your work?
  • In the 1920s, Walter A Shewhart, an American physicist, engineer and statistician, was charged with improving the quality of telephone production in Bell Laboratories. He introduced and applied statistical process control methodology. 
  • In 1945, Abraham Wald from the Statistical Research Group in the US army was given permission to publish his paper on sequential probability ratio testing, following two years of restriction that was applied by the US National defense Research Committee on his work (Wald, 1945). Wald’s technique was considered a national security issue during the wartime due to the fact that SPRT was considered of special significance in allowing for substantial savings in the expected number of observations required.
  • Bristol Heart Scandal – Set up in 1998 to investigate the deaths of 29 babies undergoing heart surgery at the Bristol Royal infirmary in the late 1980s and early 1990s, the vast 529-page report effectively provided a blueprint for wider reform of the NHS.
  • Harold Shipman – On 31 January 2000, a jury found Shipman guilty of 15 murders. He was sentenced to life imprisonment and the judge recommended that he never be released. After his trial, The Shipman Inquiry, chaired by Dame Janet Smith, began on 1 September 2000. Lasting almost two years, it was an investigation into all deaths certified by Shipman. About 80% of his victims were women. His youngest victim was a 41-year-old man.[3] Much of Britain’s legal structure concerning health care and medicine was reviewed and modified as a direct and indirect result of Shipman’s crimes.
 

 

 

What are the most recent major developments in your area of research?
Nothing much.. maybe the most important is the move of NVR into an online portal .. there remain the major problem of capturing the data in time and in full. 
 
The research question emerged as follows & in this chronological consequence – 
  • CUSUM is a good tool to consider for application in clinical databases (the CUSUM bubble era). But, it doesn’t fit into any statistical model we use in clinical medicine (kay square, t-test, correlation, etc.) .. there is no clear p values!! 
  • if we can apply CUSUM on large database; how can we test its accuracy? 
  • what can be a gold standard to measure CUSUM against? 
  • What does industrial sector use? 
  • How can we acquire NVD and use it? 
  •  
 
 
 
15. What were the crucial research decisions you made?

·      Moving from Upper GI database to aortic aneurysm (NVD) & HES
·      Moving from observational (feasibility) study into experimental design
·      Validating the ‘already validated’ industrial/statistical CUSUM using NVD – defining key concepts and definitions

Putting in writing a real-time online system analysis!

 

16. Why did you use this research methodology? What did you gain from it?

·      CUSUM(SPRT) as a diagnostic test requires no complicated mathematics. The standard approach of sensitivity/specificity analysis is all what’s required. The difficulty is therefore not statistical, but rather judgemental: deciding how good a diagnostic test should be to be clinically valuable.
·      Other methodologies: RCT with Feedback from CUSUM (intervention) vs no feedback (controls). But with no solid background to CUSUM in practice, it is doubtful that such RCT will have a go ahead.
·      Retrospective case-control study .. can be done; but, will lack the prospective and real time ability to adjust CUSUM parameters .. and infringe the concept as a whole.

 
 
 
17. What were the alternatives to this methodology?
 

18. What would you have gained by using another approach?
 

19. How did you deal with the ethical implications of your work?
No challenges. Ethical approval (generic) is already agreed at VSGBI on a third party requesting access to anonymised NVD.

 

20. How has your view of your research topic changed?
from simple retrospective CUSUM application and few case studies-applied on SAGOCS; into CUSUM application on NVD; into CUSUM application in real time; into CUSUM validation using simulation and FP; into CUSUM validation using gold standard audit; into CUSUM validation using ROC. 
 
 
 

21. How have you evaluated your work?
 
22. How do you know that your findings are correct?
 
Simple clear methodology
Peer review 
Working with authoritive pioneers in the field 
Acceptance of program by r engine
 
 

23. What are the strongest/weakest parts of your work?
Strongest – methodology and automation 
Weakest- no comparing methodology/approach ever before; apart from retrospective publications 
 
 

24. What would have improved your work?
Funding …
Migration to MAC
Availability of R programmer on site 
More time availability (I did this while progressing in my career to a consultant surgeon post, and while working in a very heavy tertiary centre)

25. To what extent do your contributions generalise?
Can be applied on any major surgical database and on other vascular surgeries with enough numbers 
 

26. Who will be most interested in your work?
The quality improvement committee of the VSGBI and our hospital managers 
 
 

27. What is the relevance of your work to other researchers?
I link to QRS team on finding better methods for quality improvement
I link to the centre of statistics in medicine 
I link to quality improvement committee at VSGBI 
 
 

28. What is the relevance of your work to practitioners?
As above 
But also, I am providing a tool that allows for better judgement 

29. Which aspects of your work do you intend to publish – and where?
Five papers 
 

30. Summarise your key findings.
 

31. Which of these findings are the most interesting to you? Why?
 

32. How do your findings relate to literature in your field?
33. What are the contributions to knowledge of your thesis?
34. How long-term are these contributions?
35. What are the main achievements of your research?
36. What have you learned from the process of doing your PhD?
37. What advice would you give to a research student entering this area?
38. You propose future research. How would you start this?
39. What would be the difficulties?
40. And, finally… What have you done that merits a PhD?
 
 
 
see this one for p values – 
http://statpages.org/ctab2x2.html
http://ktclearinghouse.ca/cebm/practise/ca/calculators/statscalc
https://books.google.co.uk/books?id=hPuEpp9dxbEC&pg=PA223&lpg=PA223&dq=calculating+p+values+in+diagnostic+tests&source=bl&ots=TWyVWZtjbM&sig=BU_JCwY70WHhwyNYtZY4t1rTbFU&hl=en&sa=X&ei=0bvmVJPSI8HnUrSyhKAK&ved=0CEwQ6AEwBjgK#v=onepage&q=calculating%20p%20values%20in%20diagnostic%20tests&f=false
this gives the equations for calculations
http://www.cct.cuhk.edu.hk/stat/confidence%20interval/Diagnostic%20Statistic.htm
http://en.wikipedia.org/wiki/Diagnostic_odds_ratio
http://stats.stackexchange.com/questions/61349/how-to-calculate-the-confidence-intervals-for-likelihood-ratios-from-a-2×2-table
with R code:
http://stats.stackexchange.com/questions/61349/how-to-calculate-the-confidence-intervals-for-likelihood-ratios-from-a-2×2-table
 
 
anaemia

What to do for anaemic patient prepared for fempop bypass in few days?

09/18/2015
The outcome is significantly different (poor) for anaemic patient:

A META-ANALYSIS (BJS 2015) showed the following: (DOI: 10.1002/bjs.9861)

  • Anaemia was associated with increased mortality (OR 2·90, 2·30 to 3·68; I2 = 97 per cent; P < 0·001), acute kidney injury (OR 3·75, 2·95 to 4·76; I2 = 60 per cent; P < 0·001) and infection (OR 1·93, 1·17 to 3·18; I2 = 99 per cent; P = 0·01). 
  • Among cardiac surgical patients, anaemia was associated with stroke (OR 1·28, 1·06 to 1·55; I2 = 0 per cent; P = 0·009) but not myocardial infarction (OR 1·11, 0·68 to 1·82; I2 = 13 per cent; P = 0·67). 
  • Anaemia was associated with an increased incidence of red cell transfusion (OR 5·04, 4·12 to 6·17; I2 = 96 per cent; P < 0·001). Similar findings were observed in the cardiac and non-cardiac subgroups.


THEREFORE, the following recommendations applies to anaemic patients undergoing an operation: (DOI: 10.1002/bjs.9898) 

  • Both anaemia and blood transfusion are independently associated with adverse outcomes. 
  • Functional iron deficiency (iron restriction due to increased levels of hepcidin) is the most common cause of preoperative anaemia, and should be treated with intravenous iron. 
  • Intraoperative blood loss can be reduced with antifibrinolytic drugs such as tranexamic acid, and cell salvage should be used. 
  • A restrictive transfusion practice should be the standard of care after surgery.
femoral artery aneurysm

Femoral aneurysm – to treat or not to treat

09/18/2015
ref:

2014 Feb;59(2):343-9. doi: 10.1016/j.jvs.2013.08.090.

The current management of isolated degenerative femoral artery aneurysms is too aggressive for their natural history.

http://www.ncbi.nlm.nih.gov/pubmed/24461859

This series is large enough to provide an excellent natural history analysis of the femoral artery aneurysm.

Abstract

BACKGROUND:

Previous studies have combined anastomotic, catheter-induced, and atherosclerotic isolated femoral artery aneurysms (FAAs) to achieve adequate numbers for analysis and have recommended repair of asymptomatic FAAs with diameters ≥2.5 cm and all symptomatic FAAs. This study evaluated the contemporary management of isolated FAAs.

METHODS:

Patients with FAAs were evaluated using a standardized, prospectively maintained database by a research consortium.

RESULTS:

From 2002 to 2012, 236 FAAs were identified in 182 patients (mean age, 72 years; male-to-female ratio, 16:1) at eight institutions. The mean nonoperative mean diameter was 2.8 ± 0.7 cm, and the operative diameter was 3.3 ± 1.5 cm. FAA location was the common femoral artery in 191, superficial femoral artery (SFA) in 34, and profunda femoris artery in 11. Synchronous aneurysms (mean, 1.7 per patient) occurred in the aorta (n = 113), in the iliac (n = 109), popliteal (n = 86), and hypogastric (n = 56) arteries, and in the contralateral common femoral artery (n = 34), SFA (n = 9), and profunda femoris artery (n = 2). Of the aneurysms repaired, 66% were asymptomatic; other indications for repair were claudication (18%), local pain (8%), nerve compression (3%), rupture (2%), acute thrombosis (1%), and rest pain (0.5%). Acute aneurysm-related complications (rupture, thrombosis, embolus) were associated (P < .05) with FAA diameter >4 cm and intraluminal thrombus, but not location. Mean diameter of asymptomatic aneurysms that developed acute complications was 5.7 ± 1.3 cm for rupture, 4 ± 1.1 cm for thrombosis, and 3.5 cm for embolus. Repair was by interposition or bypass graft in 177 FAAs and by endovascular repair in three SFA aneurysms. Two perioperative deaths, of myocardial infarction and multisystem organ failure, occurred at 30 days. Operative complications included wound infection (6%), seroma (3%), and bleeding (2%). No amputations occurred through 5 years in the operative or nonoperative groups. Survival in operated-on patients was 99% (n = 138) at 3 months, 92% at 1 year, and 81% (n = 20) at 5 years.

CONCLUSIONS:

This largest study of isolated FAAs demonstrates that (1) acute complications did not occur in FAAs ≤3.5 cm, repair criteria of asymptomatic FAAs should be changed to >3.5 cm, and chronic intraluminal thrombus should reduce the threshold for repair, and that (2) current indications for symptomatic FAA repair result in low morbidity and should remain unchanged.
Copyright © 2014. Published by Mosby, Inc.

Direct oral anticoagulation

Direct oral anticoagulants (DOA) – compares favourably to warfarin

08/31/2015

Ref. circulation 2015 

http://www.ncbi.nlm.nih.gov/m/pubmed/25995317/
This is very useful article on the newest addition to well known meds:

Efficacy and Harms of Direct Oral Anticoagulants in the Elderly for Stroke Prevention in Atrial Fibrillation and Secondary Prevention of Venous Thromboembolism: Systematic Review and Meta-Analysis.

Sharma M, et al. Circulation. 2015.

Abstract

BACKGROUND: Evidence regarding the use of direct oral anticoagulants (DOACs) in the elderly, particularly bleeding risks, is unclear despite the presence of greater comorbidities, polypharmacy, and altered pharmacokinetics in this age group.

METHODS AND RESULTS: We performed a systematic review and meta-analysis of randomized trials of DOACs (dabigatran, apixaban, rivaroxaban, and edoxaban) for efficacy and bleeding outcomes in comparison with vitamin K antagonists (VKA) in elderly participants (aged ≥75 years) treated for acute venous thromboembolism or stroke prevention in atrial fibrillation. Nineteen studies were eligible for inclusion, but only 11 reported data specifically for elderly participants. The efficacy in managing thrombotic risks for each DOAC was similar or superior to VKA in elderly patients. A nonsignificantly higher risk of major bleeding than with VKA was observed with dabigatran 150 mg (odds ratio, 1.18; 95% confidence interval, 0.97-1.44) but not with the 110-mg dose. Significantly higher gastrointestinal bleeding risks with dabigatran 150 mg (1.78, 1.35-2.35) and dabigatran 110 mg (1.40, 1.04-1.90) and lower intracranial bleeding risks than VKA for dabigatran 150 mg (0.43, 0.26-0.72) and dabigatran 110 mg (0.36, 0.22-0.61) were also observed. A significantly lower major bleeding risk in comparison with VKA was observed for apixaban (0.63, 0.51-0.77), edoxaban 60 mg (0.81, 0.67-0.98), and 30 mg (0.46, 0.38-0.57), whereas rivaroxaban showed similar risks.

CONCLUSIONS: DOACs demonstrated at least equal efficacy to VKA in managing thrombotic risks in the elderly, but bleeding patterns were distinct. In particular, dabigatran was associated with a higher risk of gastrointestinal bleeding than VKA. Insufficient published data for apixaban, edoxaban, and rivaroxaban indicate that further work is needed to clarify the bleeding risks of these DOACs in the elderly.

SYSTEMATIC REVIEW REGISTRATION: http://www.crd.york.ac.uk/PROSPERO. Unique identifier: PROSPERO CRD42014007171/.

© 2015 American Heart Association, Inc.

familial AAA;

Should you ‘mark’ your AAA patient as ‘FAMILIAL’

08/18/2015
Sources: EJVES Aug 2015

Many definitions exist, the easiest is when at least one first-degree relative (parent, sibling, offspring) is diagnosed with an aortic aneurysm. Based upon family history review, the proportion of patients with AAA with familial AAA is around 13% (range 6–36%).2 Ultrasound screening of the relatives of those with AAAs suggests a prevalence of 17% (range 9–29%) in men and 4% (range 0–11%) in women.

Clinical phenotypes – Studies suggest that patients with familial AAA are significantly more likely to be female, younger, have fewer cardiovascular risk factors (e.g., hypertension and diabetes mellitus), and possibly have a lower carotid intima-media thickness. Studies also show a high rate of thoracic aortic aneurysms and an increased rate of bilateral iliac aneurysms in patients with familial AAA. Relatives of patients with familial AAA also appear to have increased aortic diameters. 

In any case, additional environmental effects, such as smoking, hypertension and hypercholester- olemia could enhance the risk of aneurysm formation and therefore explain the variability in expression of the disease. 

Most accepted genetic aortic aneurysm syndromes are caused by defects in genes involved in the transforming growth factor-b pathway,8 and are associated with syn- dromes like Marfan disease and LoeyseDietz syndrome. 

Until now, family studies have detected a linkage with the 19q13 and 4q31 regions in the genome but without identifying specific genes in these regions. A genome- wide single nucleotide polymorphism with AAA include DAB2IP, LRP1, LDLR, ANRIl, and SORT1.10 Having one of these alleles results in an additional `20% risk for devel- oping AAA; however, the causal relationship of these poly- morphisms still needs to be elucidated.

ACTION PLAN – 

The present American College of Cardiology/American Heart Association guidelines recom- mend ultrasound screening for male relatives aged 60 years or older, while the European Society for Vascular Surgery guidelines recommend ultrasound screening of both male and female relatives aged >50 years who have a family history of AAA. 
It is not known whether endovascular aneurysm repair (EVAR) or open repair (OR) is the optimal treatment for patients with familial AAA. Only very limited data are available; however, as patients with familial AAA tend to be younger, they may benefit from OR, which carries a lower secondary intervention risk with time.  





Uncategorized

Dealing with complex systems – NHS as an example

07/26/2015
TEDx talk by Yves Morieux 

  • To deal with complexity, to enhance the nervous system, we have created what we call the smart simplicity approach based on simple rules. 
  • Simple rule number one: Understand what others do. What is their real work? We need to go beyond the boxes, the job descriptions, beyond the surface of the container, to understand the real content. Me, designer, if I put a wire here, I know that it will mean that we will have to remove the engine to access the lights. 
  • Second, you need to reenforce integrators.Integrators are not middle offices, they are managers, existing managers that you reinforce so that they have power and interest to make others cooperate. How can you reinforce your managers as integrators?By removing layers. When there are too many layers people are too far from the action, therefore they need KPIs, metrics, they need poor proxies for reality. They don’t understand reality and they add the complicatedness of metrics, KPIs. By removing rules — the bigger we are, the more we need integrators,therefore the less rules we must have, to give discretionary power to managers. And we do the opposite — the bigger we are, the more rules we create. And we end up with the Encyclopedia Britannica of rules.You need to increase the quanitity of power so that you can empower everybody to use their judgment, their intelligence. You must give more cards to people so that they have the critical mass of cards to take the risk to cooperate, to move out of insulation. Otherwise, they will withdraw. They will disengage. These rules, they come from game theory and organizational sociology. You can increase the shadow of the future. Create feedback loops that expose people to the consequences of their actions. This is what the automotive company did when they saw that Mr. Repairability had no impact. They said to the design engineers: Now, in three years, when the new car is launched on the market, you will move to the after sales network, and become in charge of the warranty budget, and if the warranty budget explodes, it will explode in your face. (Laughter) Much more powerful than 0.8 percent variable compensation. 
  • You need also to increase reciprocity, by removing the buffers that make us self-sufficient. When you remove these buffers, you hold me by the nose, I hold you by the ear. We will cooperate. Remove the second TV. There are many second TVs at work that don’t create value, they just provide dysfunctional self-sufficiency. 
  • You need to reward those who cooperate and blame those who don’t cooperate. The CEO of The Lego Group, Jorgen Vig Knudstorp, has a great way to use it. He says, blame is not for failure, it is for failing to help or ask for help. It changes everything. Suddenly it becomes in my interest to be transparent on my real weaknesses, my real forecast, because I know I will not be blamed if I fail, but if I fail to help or ask for help. When you do this, it has a lot of implications on organizational design. You stop drawing boxes, dotted lines, full lines; you look at their interplay. It has a lot of implications on financial policies that we use. On human resource management practices. When you do that, you can manage complexity, the new complexity of business, without getting complicated. You create more value with lower cost. You simultaneously improve performance and satisfaction at work because you have removed the common root cause that hinders both. Complicatedness: This is your battle, business leaders. The real battle is not against competitors. This is rubbish, very abstract. When do we meet competitors to fight them? The real battle is against ourselves, against our bureaucracy, our complicatedness. Only you can fight, can do it.Thank you. (Applause)

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