CRD summary

The authors concluded that the combination of negative electrocardiogram, negative troponin and negative ischaemia-modified albumin within 3 hours of chest pain has a high probability of excluding acute coronary syndrome in the emergency department. The poor reporting of review methods and differences in results between studies meant it was not possible to confirm the reliability of these results.

Authors' objectives

To assess the performance of ischaemia-modified albumin (IMA) in ruling out acute coronary syndrome (ACS) in patients attending the emergency department (ED).

Searching

MEDLINE was searched and unpublished data were obtained from known investigators.

Study selection

Assessment of study quality

The authors did not state that they assessed validity.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

For each study, the sensitivity and NPV were calculated for each test or combination of tests reported. For studies reporting serial troponin levels, the maximal value within the first 6 hours was used. In follow-up studies, patients without follow-up data were classified as lost to follow-up. In the review, the triple prediction test (TPT) was defined as positive if any one of ECG, troponin or IMA were positive; a negative TPT was defined as three negative tests.

Methods of synthesis

Results of the review

Eight studies were included. There were 6 acute diagnosis studies (n=1,612) and 5 follow-up studies (n=1,307; 1,197 of whom were analysed); some studies were classified as both acute diagnosis studies and follow-up studies (classified according to the reference standard used).

Acute diagnosis studies.

Ten different combinations of tests were evaluated. Studies varied with respect to ACS rate: 2 studies had ACS rates of approximately 8%, 3 studies had ACS rates of approximately 17%, and 1 study had an ACS rate of 63%. The results of the individual studies were presented in forest plots (acute diagnosis and follow-up studies presented separately).

The sensitivity of the TPT was 94.4% (95% CI: 90, 97; based on 2 studies, n=571) and the NPV was 97.1% (95% CI: 95, 99; based on 3 studies, n=1,062). The addition of rest MPI to the TPT did not significantly improve sensitivity.

Follow-up studies.

Ten different combinations of tests were evaluated. The duration of follow-up ranged from 30 days to 6 months. Studies varied with respect to ACS rate: the rates ranged from 3.9% at 6 months in 1 study to 42.6% at 30 days in 1 study. The sensitivity of the TPT was 89.2% (95% CI: 82, 94; based on 1 study, n=519) and the NPV was 94.5% (95% CI: 95, 99; based on 2 studies, n=1,010). The addition of rest MPI to the TPT did not significantly improve sensitivity.

Authors' conclusions

The combination of a negative ECG, negative troponin and negative IMA has a high probability of ruling out ACS in the ED.

CRD commentary

The review appeared to address a clear question that was defined in terms of the participants and outcomes. The inclusion criteria stated that studies that evaluated IMA were eligible, but the review also evaluated IMA as part of the TPT and a variety of other tests and combinations of tests that did and did not contain IMA. Thus, the inclusion criteria were not strictly adhered to. Only one database was searched and attempts were made to locate unpublished data, but it is possible that some relevant studies might have been missed. In addition, it was not reported whether any language restriction had been applied. Study validity was not assessed, so the results from these studies and any synthesis might not be reliable. Sensitivity and NPV values were combined by simple averaging (effectively a fixed-effect meta-analysis weighted by sample size). It was not possible to determine if pooling was appropriate since statistical heterogeneity was not assessed and results for the individual studies were not reported. The lack of reporting of review methods, lack of a quality assessment of the individual studies, lack of reporting of differences in results between the studies, and probably inappropriate methods of pooling meant it was not possible to confirm the reliability of these results.

Implications of the review for practice and research

Practice: The authors stated that the results from the review are not generalisable and do not support the routine use of the TPT in clinical practice. Patients with a negative TPT but with a high-risk history or physical findings may still require further evaluation. Patients with an elevated IMA should be evaluated according to the usual protocols for ACS.

Research: The authors stated that an international trial (IMAGINE) is currently evaluating the role of IMA.

Bibliographic details

Peacock F, Morris D L, Anwaruddin S, Christenson R H, Collinson P O, Goodacre S W, Januzzi J L, Jesse R L, Kaski J C, Kontos M C, Lefevre G, Mutrie D, Sinha M K, Uettwiller-Geiger D, Pollack C V. Meta-analysis of ischemia-modified albumin to rule out acute coronary syndromes in the emergency department. American Heart Journal 2006; 152(2): 253-262. [PubMed: 16875905]

Indexing Status

Subject indexing assigned by NLM

MeSH

Angina, Unstable /diagnosis; Biological Markers /blood; Creatine Kinase, MB Form /analysis; Electrocardiography; Emergency Service, Hospital; Humans; Myocardial Infarction /diagnosis; Predictive Value of Tests; Risk Assessment; Sensitivity and Specificity; Serum Albumin /analysis; Syndrome

AccessionNumber

12006003868

Database entry date

31/01/2008

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.