Press releases Monday 18 May to Friday 22 May 2009
Please remember to credit the BMJ
as source when publicising an article and to tell your readers that they can
read its full text on the journal's website (http://www.bmj.com).
(1) Study calls for "as soon as possible" treatment standard for heart attack patients
(2) Blood pressure lowering drugs should not be limited to people with high blood pressure
(3) Prevalence of variant CJD agent in Britain remains uncertain
(1) Study calls for "as soon as possible" treatment standard for heart attack patients
(Research: Association of door-to-balloon time and mortality in patients admitted to hospital with ST elevation myocardial infarction: national cohort study)
http://www.bmj.com/cgi/doi/10.1136/bmj.b1807
Once in hospital, heart attack patients should be treated without delay to cut their risk of death, ideally within even less than the 90 minutes currently recommended by clinical guidelines, say researchers in a paper published on bmj.com today.
After a heart attack, patients often undergo a procedure using a balloon-tipped catheter that is inserted into a main artery, pushed into the narrowed coronary artery, and inflated to clear the blockage. This is called primary percutaneous coronary intervention, or more simply balloon angioplasty.
The time between a patient's arrival at hospital and first balloon inflation is known as the "door-to-balloon time." The current target is 90 minutes, but the benefits of reducing this time even further is still unclear.
So researchers based in the United States set out to investigate the association between door-to-balloon time and deaths in hospital among patients undergoing balloon angioplasty after a heart attack.
They analysed data for 43,801 patients from the American College of Cardiology National Cardiovascular Data Registry. All patients underwent balloon angioplasty within 12 hours of a heart attack at a United States acute care hospital between 2005 and 2006.
Average door-to-balloon time was 83 minutes, with over half of patients (58%) treated within 90 minutes of admission. Overall in-hospital mortality was 4.6%. A greater proportion of patients who had longer door-to-balloon times were women, non-white, and, on average, older than patients with shorter door-to-balloon times. They also had more comorbidities (other disorders, such as diabetes and high blood pressure) than patients with shorter door-to-balloon times.
After adjusting for factors that may have affected the results, longer door-to-balloon times were associated with a higher risk of in-hospital mortality. For example, 3% of patients with door-to-balloon times of 30 minutes died in hospital, while 4.3% of patients with door-to-balloon times of 90 minutes died. The highest mortality rate (10.3%) was for patients with door-to-balloon times of 270 minutes.
These results indicate that any delay in door-to-balloon time for heart attack patients undergoing balloon angioplasty is associated with higher mortality, even among patients treated within 90 minutes of admission, say the authors.
"Rather than accepting the 90 minute door-to-balloon time benchmark, our data support calls for an 'as soon as possible' standard for patients undergoing primary percutaneous coronary intervention. Such an approach, using necessary safeguards against inappropriate treatment, offers the potential for notable mortality reduction," they conclude.
Contacts:
Saif Rathore or Harlan Krumholz, Yale University School of Medicine, New Haven, Connecticut, USA
Email: harlan.krumholz@yale.edu
Blood pressure lowering drugs should be offered to anyone old enough to be at risk of a heart attack or stroke (or who is otherwise known to be at risk), regardless of their blood pressure, according to the largest analysis of blood pressure trials to date, published on bmj.com today.
Cardiovascular disease is the leading cause of death throughout the world. For 65 year olds in England and Wales the risk of having a heart attack in the next 10 years is about 10% for men and 5% for women. The increase in blood pressure during a person's life, which affects nearly everyone, is one of the main reasons for strokes and heart attacks being so common.
Despite the widespread use of blood pressure lowering drugs and the results of many randomised trials, uncertainty remains about which drugs to use and whom to treat. For example, does the preventive effect of drugs differ in people with and without a history of heart disease? And should blood pressure lowering drugs be limited to people with high blood pressure?
To answer these questions, Professor Malcolm Law and colleagues from the Wolfson Institute of Preventive Medicine at Barts and The London School of Medicine analysed the findings of 147 blood pressure trials published between 1966 and 2007, involving 464,000 people.
The results show that using any one of the main classes of blood pressure lowering drugs at standard dose reduced fatal and non-fatal heart attacks by about a quarter and stroke by about a third. Heart failure was also reduced by about a quarter. The reductions in disease were similar in people with and without clinical cardiovascular disease and regardless of blood pressure before treatment.
All the classes of blood pressure lowering drugs had a similar effect for a given reduction in blood pressure that was accurately predicted from epidemiological studies of blood pressure and subsequent disease with two exceptions - an extra protective effect of beta-blockers given shortly after a heart attack and a small additional effect of calcium channel blockers in preventing stroke.
And combining the results with two previously published studies showed that three drugs together, each at low dose to minimise side effects, could increase the preventive effect, reducing heart attacks by about 45% and stroke by about 60%.
Professor Malcolm Law said: "The results show that blood pressure lowering drugs should be offered to anyone at sufficient risk to benefit from treatment, whatever their reason for being at risk." However, the exact age range for being most at risk of heart attack and stroke could not be defined precisely from this study, which only looked at randomised trials in people aged 60-69.
In an accompanying editorial, Richard McManus from the University of Birmingham and Jonathan Mant from the University of Cambridge, say that these findings reinforce the view that treatment to lower blood pressure should be offered on the basis of risk, regardless of blood pressure. These data support the use of a polypill to lower the risk of cardiovascular disease in people at high risk without first checking their blood pressure, they add.
Contacts:
Malcolm Law, Professor of Epidemiology or Professor Nicholas Wald, Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine, Queen Mary University of London, UK
Email: m.r.law@qmul.ac.uk or n.j.wald@qmul.ac.uk
Richard McManus, Clinical Senior Lecturer, Primary Care Clinical Services, University of Birmingham, Birmingham, UK
Email: r.j.mcmanus@bham.ac.uk
(2) Prevalence of variant CJD agent in Britain remains uncertain
(Research: Prevalence of disease related prion protein in anonymous tonsil specimens in Britain: cross sectional opportunistic survey)
http://www.bmj.com/cgi/doi/10.1136/bmj.b1442
(Editorial: Prevalence of variant CJD in the UK)
http://www.bmj.com/cgi/doi/10.1136/bmj.b435
First results from a large tissue survey in Britain of the agent that causes variant Creutzfeldt-Jakob disease (vCJD) are unable so far to establish that the prevalence is lower than that given by previous estimates, concludes a study published on bmj.com today.
Although the risk of dietary exposure to the agent that causes vCJD has been virtually eliminated, uncertainty remains about how many people carry the infectious agent and will eventually develop the disease.
Calculations based on cases of vCJD to 2004 predicted between 10 and 190 further clinical cases over the next few decades. However, a study of appendix and tonsil tissues predicted a much higher level of cases - between 520 and 13,000.
To resolve this discrepancy, and ensure that proportionate public health measures are implemented, a research team led by Jonathan Clewley and Noel Gill at the Health Protection Agency in London, set out to establish a more accurate prevalence of disease-associated prion protein in the population of Britain.
They tested 63,007 anonymous tonsil samples from people of all ages who had had their tonsils removed between 2004 and 2008 in hospitals throughout England and Wales.
Of these, 12,753 were from people born between 1961 and 1985 (the group in which most vCJD cases have arisen) and 19,908 were from people born between 1986 and 1995 who would have also been exposed to meat or meat products contaminated with the agent that causes bovine spongiform encephalopathy (BSE) in cattle.
Samples were screened for the presence of the prion protein (PrPCJD) - known to accumulate to relatively high levels in the tonsils of people with vCJD. Two sensitive immunological tests were used and any sample that showed reactivity underwent more comprehensive and specific testing to confirm whether or not the protein was present.
None of the samples was positive for the presence of the protein, suggesting that the prevalence of vCJD carriers in Britain may be lower than that given by previous estimates, with an upper limit of 289 per million in people born between 1961 and 1985, say the authors. This result is, however, still consistent with the earlier study of appendix tissue that showed a prevalence of 292 per million, they add.
They call for more data through continuing to archive and test tonsils, and other anonymous tissue samples, from people born before 1996. This will help guide a proportionate public health response to limit the threat of healthcare associated transmission of vCJD, they conclude.
An accompanying editorial argues that the chance that no one in the UK is incubating the disease is unlikely, but that the limited number of cases and diagnostic problems make accurate measurement difficult.
Maurizio Pocchiari, a neurology expert based in Rome, suggests that repeating surveys of prion protein in tissue specimens may not yield further information unless a more sensitive and specific test is developed. Therefore, the precautionary measures already in place must be maintained to avoid transmission of vCJD between humans and surveillance of disease in the UK and in the rest of Europe should remain alive.
He also says that public health authorities in other countries should not carry out such studies, as an enormous number of samples would be needed to yield useful information because exposure to the BSE agent in the rest of the world is probably much lower than in the UK.
Contacts:
Research: Press Office, Health Protection Agency, Centre for Infections, London, UK
Email: pressoffice@hpa.org.uk
Editorial: Maurizio Pocchiari, Director of Research, Department of Cell Biology and Neurosciences, Istituto Superiore di Sanita, Rome, Italy
Email: Maurizio.pocchiari@iss.it
FOR ACCREDITED JOURNALISTS
For more information please contact:
Emma Dickinson
Tel: +44 (0)20 7383 6529
Email: edickinson@bmj.com
Press Office telephone : 020 7383 6254 (Weekdays : 0900hrs - 1800hrs)
British Medical Association
BMA House, Tavistock Square, London WC1H 9JP
and from:
the EurekAlert website, run by the
American Association for the Advancement of Science (http://www.eurekalert.org)
[[$FOOTER]]