Matters arising

Cardiovascular diseases
Volume 193 - Issue 9

Acute coronary syndromes: consensus recommendations for translating knowledge into action

Authors:  David B Brieger, Derek Chew, Constantine Aroney, Phil Aylward, Darren Walters, Anne-Maree Kelly and Andrew Boyden

Med J Aust 2010; 193 (9): 550-553. || doi: 10.5694/j.1326-5377.2010.tb04046.x
Published online: 1 November 2010
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In reply: We thank Forge for his continued and welcome contribution to this debate.

He is critical of our reference to the National Institute for Health and Clinical Excellence (NICE) guidelines, which show an inverse relationship between rates of intervention and clinical outcomes. The NICE analysis is supported by others,1 and we stand by our argument that if studies with greater differences in the randomisation arms show a greater treatment effect, the strength of the evidence supporting the intervention is enhanced. Dismissing this type of analysis on scientific grounds is disingenuous and contrary to National Health and Medical Research Council recommendations regarding the assessment and application of scientific evidence.2

Data supporting the role of invasive therapy in management of acute coronary syndromes (ACS) continue to evolve. A recently published patient-level meta-analysis of three studies, comprising 5-year outcomes of 5467 patients, showed a significant reduction in myocardial infarction (hazard ratio [HR], 0.77; 95% CI, 0.65–0.90), with consistent trends towards reduction in cardiovascular death (HR, 0.83; 95% CI, 0.68–1.01) and all death (HR, 0.90; 95% CI, 0.77–1.05).3

This meta-analysis showed the largest absolute benefit among the highest-risk patients assessed by a global risk score, supporting evidence that risk stratification should involve more comprehensive clinical evaluation than that provided by a single biomarker.4

It is true that these studies have not shown a reduction in mortality. This is most likely to be an issue of power. Based on the number of patients studied in randomised trials so far, the power needed to detect a 10% difference in mortality between treatment strategies is only 27%.1

Regarding TRANSFER-AMI (Trial of Routine Angioplasty and Stenting after Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction), Forge now agrees that there are limitations associated with the high transfer rates in the conservative arm, which are greater than those seen in contemporary Australian practice. When the conservative arm receives better-than-standard practice, the direct effect is a bias of the outcome towards the null, limiting the quantification of absolute benefit associated with routine urgent transfer. Forge dismisses CARESS-in-AMI (Combined Abciximab Reteplase Stent Study in Acute Myocardial Infarction) because of the management strategy in the conservative arm. The main limitation of this study is its small size; in an earlier study of 16 588 patients, combination half-dose reteplase and full-dose abciximab treatment had comparable mortality to full-dose reteplase alone.5

Finally, we would like to re-emphasise that National Heart Foundation of Australia (NHFA)/Cardiac Society of Australia and New Zealand (CSANZ) ACS guidelines are not prescriptive. They are designed to provide guidance to individual clinical practice, not to mandate one form of practice. Adherence to guidelines has been demonstrated to improve outcomes when instituted as part of a coordinated quality improvement strategy across a health care system. In addition to provision of optimal medical therapy and risk factor modification, approaches to ACS that incorporate timely access to revascularisation have made a significant contribution to this improvement in outcomes.

Authors

  • David B Brieger1
  • Derek Chew2
  • Constantine Aroney3
  • Phil Aylward2,4
  • Darren Walters5
  • Anne-Maree Kelly6
  • Andrew Boyden7
  • 1. Coronary Care and Coronary Interventions, Concord Repatriation General Hospital, Sydney, NSW.
  • 2. Southern Adelaide Health Service, Adelaide, SA.
  • 3. Holy Spirit Northside Private Hospital, Brisbane, QLD.
  • 4. Flinders Medical Centre, Adelaide, SA.
  • 5. Prince Charles Hospital, Brisbane, QLD.
  • 6. Joseph Epstein Centre for Emergency Medicine Research, Western Health, Melbourne, VIC.
  • 7. National Heart Foundation of Australia, Canberra, ACT.

Correspondence: davidb@email.cs.nsw.gov.au

Competing interests

The authors are all members of the NHFA ACS Guideline Implementation and Advocacy Working Group. David Brieger has been a member of advisory boards for Sanofi-Aventis, Eli Lilly, AstraZeneca and Boehringer Ingelheim, and has received research grants from Sanofi-Aventis, Eli Lilly, Schering-Plough and Merck Sharp & Dohme. Derek Chew has been a board member for Sanofi-Aventis, Eli Lilly and AstraZeneca, and has received reimbursement for travel/accommodation expenses from AstraZeneca and fees for expert testimony from Sanofi-Aventis and Eli Lilly. Constantine Aroney has received reimbursement for travel/accommodation expenses from Sanofi-Aventis, Eli Lilly and Medtronic and payment for developing educational presentations from Eli Lilly, Pfizer and The Medicines Company. Darren Walters has received a research fellowship from Medtronic and reimbursement of travel/accommodation expenses from Eli Lilly, AstraZeneca, Medtronic, GlaxoSmithKline, Johnson and Johnson, Universal Biosensors, Boston Scientific and Abbott Australasia, as well as organisations including the American Heart Association, the Royal Australasian College of Physicians and CSANZ. Philip Aylward has received research honoraria, speaker fees or travel assistance from TIMI Group (Harvard University), VIGOUR Group (Duke University), Pfizer, AstraZeneca, Eli Lilly, Boehringer Ingelheim and Sanofi-Aventis, and is a member of advisory boards to AstraZeneca, Sanofi-Aventis, Eli Lilly, CSL, Boehringer Ingelheim, and Pfizer. Anne-Maree Kelly has been on advisory boards for Sanofi-Aventis, AstraZeneca and Medical Developments International, and has received reimbursement for travel/accommodation expenses from Radiometer.

References

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