Mortality and volume of cases in paediatric cardiac surgery: retrospective study based on routinely collected data
BMJ 2002; 324 doi: https://doi.org/10.1136/bmj.324.7332.261 (Published 02 February 2002) Cite this as: BMJ 2002;324:261
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Editor – The response submitted by Drs Gibbs and Cunningham [1] to Dr Spiegelhalter’s article presenting data collected during the Bristol Royal Infirmary Inquiry [2] presents a cogent argument, but is based on a false premise. Dr Spiegelhalter is not guilty of using some sort of validated and/or synthesised data source to provide mortality rates for the Bristol paediatric cardiac unit for the period in question: as with the other units, the Bristol figures are merely those that were volunteered to the CSR or HES by the clinicians concerned at the time in question. This has the disadvantage that such data is unverified and potentially unreliable but, at least, thereby puts Bristol on a “level playing field” with other units.
It is interesting that Drs Gibbs and Cunningham assume that an authoritative record of paediatric cardiac surgery at Bristol would be available; it would, indeed, have been fairly straightforward (if somewhat laborious) for the Inquiry to have put together such a resource. However, although the statisticians whom the Inquiry engaged devoted a certain amount of effort to analysing the extent to which the different sources of mortality data “agree”, no attempt was made to synthesise the sources in question, to cross-reference each to the other in an attempt to produce the kind of accurate figures which Drs Gibbs and Cunningham postulate. One would assume that the Bristol Royal Infirmary Inquiry – somewhere amongst its 14 million pounds’ worth of work spread over 3 years – would be able to answer the questions, “How many children received heart surgery at Bristol, and how many of these died?” These questions remain unanswerable.
It is to be hoped that the UK Central Cardiac Audit Database will not only greatly ease the generation of reliable and truly comparable mortality rates, but will also provide the kind of “early warning system” that will prevent future tragedies on the scale of Bristol. I note with extreme regret, however, that CCAD shows no inclination to track non-fatal outcomes to cardiac surgery. Children who survive heart surgery with brain damage or other non-fatal complications have been – and remain – grossly overlooked in the analysis of cardiac surgical performance (for example, this issue receives precisely one paragraph in the Kennedy report). People are often surprised to learn that there is absolutely no way of establishing whether the incidence of brain damage following heart surgery was any higher at Bristol than elsewhere; they are astonished to learn that there is still no way of comparing various centres’ records in this area.
Dr Kate Bull has produced an extremely constructive paper on this subject [3], and the Brompton and Harefield Inquiries made equally useful observations and recommendations [4]. Unfortunately, those who commission such views in the first place have persisted in all-but ignoring the findings (whilst, of course, offering lip-service to the contrary).
Laurence Vick
Solicitor, Michelmores, 18 Cathedral Yard, Exeter. EX1 1HE.
e-mail: lnv@michelmores.com
1. Gibbs JL, Cunningham D. Unreliability of volunteered mortality data. bmj.com, 13 Feb 2002.
2. Spiegelhalter D. Mortality and volume of cases in paediatric cardiac surgery: retrospective study based on routinely collected data. BMJ 2001;323:1–5.
3. Bull, C. Key Issues in Retrospective Evaluation of Morbidity Outcomes Following Paediatric Cardiac Surgery. Bristol Royal Infirmary Inquiry, 2000. [available online at http://www.bristol-inquiry.org.uk/images/seminars/Bmr.pdf]
4. Evans R et al. Report of the Independent Inquiries into Paediatric Cardiac Services at the Royal Brompton Hospital and Harefield Hospital. 2001. [available online at http://www.rbh.nthames.nhs.uk/GENERAL/Press/Paediatricinquiry/FullReport...
Competing interests: No competing interests
Unreliability of volunteered mortality data
John L Gibbs, et al.
bmj.com, 13 Feb 2002
Editor – on re reading our letter of 13th Feb in response
to Spiegelhalter's article of case volume and mortality
we are concerned that our statement "Overall tracked
mortalities were 25% higher than reported mortalities"
may have given the impression that total tracked
mortality in the UK was 25% higher than reported
mortality. What we should have said is "Overall tracked
30-day mortality in individual hospitals was up to 25%
higher than reported discharge mortality". Our
message concerning the dangers of comparison of
validated and unvalidated data remains unchanged.
John L Gibbs
David Cunningham
Competing interests: No competing interests
Editor – David Spiegelhalter’s article1 adds to the already
persuasive data from the early 1990’s suggesting an inverse
relationship between volume of cases and mortality in
congenital heart disease surgery. But he goes on to compare
mortality derived from the Cardiac Surgical Register (CSR),
Hospital Episode Statistics (HES) and the Bristol Inquiry.
This comparison is fundamentally flawed and is almost
certainly unfairly biased against Bristol. Mortality rates
in Bristol have been so closely scrutinised for the period
covered by the inquiry that they are highly likely to be
accurate. There has, however, to our knowledge been no
attempt to validate the volunteered mortality data from CSR
or HES data from the same period.
The UK Central Cardiac Audit Database (CCAD),has collected
data from all UK congenital heart disease centres since
April 2000, including volunteered mortality data. CCAD, in
contrast to the CSR and HES, also tracks mortality
independently using the patient’s NHS number and a direct
link to the Office of National Statistics. Volunteered and
centrally tracked 30 day mortality rates differ
considerably. Overall tracked mortalities were 25% higher
than reported mortalities. 7 of 11 centres in England
under-reported early mortality, sometimes because patients
were discharged very early, but also sometimes because the
reporting was erroneous. Six patients who died within 7 days
of operation were wrongly reported as alive at discharge.
Furthermore, use of Hospital Episode Statistics did not
improve accuracy of status reporting. In a sample of nearly
3,000 procedures carried out in between 1/4/2000 and
31/3/2001, HES data under-reported the total number of
procedures by 10% and under-reported 30 day deaths by 9%,
but also classified 1% of surviving patients erroneously as
deceased. We understand that links between ONS and HES are
being explored but those links were not in existence when
the HES 2000-2001 data became available or at the time of
the Bristol Inquiry.
It is likely that the differences between mortality in the
volunteered CSR data and the Bristol Inquiry data were of at
least equal magnitude to those described above. Any new or
past comparison of mortality rates which fails to take into
account the difference in data quality from non validated
sources and from the Bristol over the period of the Inquiry
risks doing serious injustice to Bristol as well as to the
profession’s ongoing attempts to restore the public’s
confidence in congenital heart disease services in the UK.
John L Gibbs FRCP
Lead Clinician, UK Congenital Heart Disease Central Cardiac
Audit Database, and consultant paediatric cardiologist,
Yorkshire Heart Centre, E Floor Jubilee Wing, Leeds General
Infirmary, Great George Street, Leeds LS1 3EX.
email: jgibbs@cwcom.net
David Cunningham PhD
Technical Director, Central Cardiac Audit Database, Royal
Brompton
Hospital, Sydney Street, London SW3 6NP.
email: adc@bio.gla.ac.uk
1. Spiegelhalter D. Mortality and volume of cases in
paediatric cardiac surgery: retrospective study based on
Competing interests: No competing interests
Re: “BRI – Mortality and volume of cases in paediatric cardiac surgery
Dear Sir,
Re: “BRI – Mortality and volume of cases in paediatric cardiac
surgery”
Mr Spiegelhalter’s paper presents further confirmation that the BRI’s
mortality record was extremely poor. What this paper does not answer is
why the mortality record was so poor and what was the BRI’s true ‘success’
rate. Many children who survived with appalling brain damage are counted
as ‘successes’.
As the father of a child who suffered horrendous brain damage, I find
it outrageous that Mr Spiegelhalter should count him as a ‘success’. It
is long past time that an in depth study was conducted of what were
Bristol’s TRUE success rates and WHY did so many children die or suffer
morbidity.
The answer is largely to be found in the fact that the surgeons were
very slow. Their operation times, times on bypass and cross clamp times
were all excessive. As Mr Pawade said at the GMC, ‘the fate of the child
is decided in theatre’ and ‘it is a race against time’ . Similarly,
Professor Angellini concerning morbidity said, ‘complications are a well
known fact to be enhanced by prolonged operations’
In respect of bypass times, a Great Ormond Street Hospital study
says that patients with adverse neurological events had a significantly
longer mean cardiopulmonary bypass time than normal survivors (113 v 93
minutes; p<_0.05 as="as" did="did" patients="patients" who="who" subsequently="subsequently" died="died" _199="_199" v="v" _93="_93" minutes="minutes" p0.001.="p0.001." p="p"/> If one examines Mr Wisheart’s operations, taking 113 minutes bypass
time as per the above study as an indicator that the length of time on
bypass has probably (p<_0.05 resulted="resulted" in="in" an="an" adverse="adverse" neurological="neurological" event.="event." one="one" finds="finds" that="that" from="from" a="a" sample="sample" of="of" just="just" over="over" hundred="hundred" operations="operations" approximately="approximately" _60="_60" their="their" bypass="bypass" times="times" exceeded="exceeded" _113="_113" minutes.="minutes." the="the" horrifying="horrifying" implication="implication" this="this" is="is" majority="majority" mr="mr" wishearts="wishearts" suffered="suffered" brain="brain" damage.="damage." p="p"/> The question of how many children survived with brain damage has
never been examined. The recent £14 million pound Public Inquiry
carefully avoided this issue. No doubt due to the fact that the solicitors
who ran this Inquiry were from the Treasury and that they had a vested
interest in ensuring that these sorts of studies and facts were avoided.
It also explains why my wife and I were not allowed representation and why
we were effectively barred from this supposedly ‘Public’ Inquiry.
It is in the Public Interest that the true failure rate at the BRI
should be ascertained. The reasons for this need to fully revealed. I
urge Mr Spiegelhalter to undertake a comprehensive study that focuses on
the surgeons’ surgical times, their bypass times, their cross-clamp times,
the times to extubation and the statistical association that this has on
excess mortality and morbidity at the BRI.
Far too much time and money has already been wasted by the Public
Inquiry on such spurious reasons as the ‘split-site’, which played a
negligible role as evidenced by the fact that Mr Pawade used exactly the
same facilities for his first 88 operations with only one death . Why was
Mr Pawade’s mortality rate some fifteen times lower than Mr Wisheart’s?
Could it be because he had been properly trained, because he recognised
that ‘speed is of the essence’ and that the child’s fate is largely
decided in theatre?
Yours sincerely
Jim Stewart
Blue Haze, Hillside Road, Sidmouth, Devon, EX10 8JD
E-mail: ukroo@aol.com
1) GMC 9-5F and 9-6D respectively.
2) GMC3-63B.
3) Incidence of neurological complications of surgery for congenital heart
disease by P Fallon, JM Aparicio, MJ Elliot and FJ Kirkham – Archives of
Disease in Childhood - 1995
4) As contained in the internal audit conducted by Dr Bolsin and Dr Black
5) GMC 9-1C
Competing interests: No competing interests