CRD summary

This review assessed functional testing used to assess graft stenosis or the progression of coronary artery disease after coronary artery bypass graft. The authors concluded that stress ventricular imaging was superior to exercise treadmill testing alone. The quality of the included studies was not assessed and relevant studies might have been missed, therefore the reliability of the conclusions was unclear.

Authors' objectives

To assess the diagnostic accuracy of exercise treadmill testing (ETT), stress myocardial perfusion imaging (MPI) and stress echocardiography for detecting graft stenosis or the progression of coronary disease following coronary artery bypass graft (CABG) surgery.

Searching

MEDLINE was searched (the search terms were provided) and the references of relevant articles were checked for English language articles.

Study selection

Assessment of study quality

The authors did not state that they assessed validity, although only studies that carried out an interpretation of the diagnostic tests and the gold standard that was blinded to the other test, as well as patient identity and other clinical data, were eligible for inclusion. In addition, studies were only included if the data from cardiac catheterisation had been interpreted by at least two individuals.

Data extraction

Two reviewers independently extracted the data. Any disagreements were resolved by consensus or by a third reviewer. The results of the tests, as well as details of the specific tests and when they took place, were extracted. Indeterminate test results were excluded from calculations of the sensitivity and specificity.

Methods of synthesis

Results of the review

Nineteen studies (n=1,649) were included.

ETT (14 studies; of the 804 tests performed, 112 were excluded due to indeterminate results).

When graft stenosis or disease progression was defined as a diameter reduction of greater than 50%, the sensitivity was 45% (95% confidence interval, CI: 36, 54) and the specificity was 82% (95% CI: 68, 95). Both values increased slightly when the definition was changed to a diameter of greater than 70%. The PPV ranged from 22 to 71% and the NPV from 93 to 60% in patients with a low and high pre-test probability, respectively, of graft stenosis or disease progression.

Stress MPI (11 studies; 464 tests).

When graft stenosis or disease progression was defined as a diameter reduction of greater than 50%, the sensitivity was 68% (95% CI: 51, 86) and the specificity was 84% (95% CI: 78, 91). The sensitivity increased when the definition was changed to a diameter of greater than 70%. The PPV ranged from 32 to 81% and the NPV from 96 to 72% in patients with a low and high pre-test probability, respectively, of graft stenosis or disease progression.

Stress echocardiography (6 studies; of the 503 tests performed, 20 were excluded due to indeterminate results).

When graft stenosis or disease progression was defined as a diameter reduction of greater than 50%, the sensitivity was 86% (95% CI: 78, 94) and the specificity was 90% (95% CI: 84, 95). The PPV ranged from 50 to 90% and the NPV from 98 to 87% in patients with a low and high pre-test probability, respectively, of graft stenosis or disease progression.

Authors' conclusions

Stress ventricular imaging was superior to ETT alone for the diagnosis of graft stenosis or progression of disease.

CRD commentary

The review addressed a clear research question using defined inclusion criteria. However, relevant studies might have been missed as only one electronic database was searched, and non-English language and unpublished studies were excluded. The review methodology was described and it included measures to avoid the introduction of error and bias. Although only blinded studies were included, other important aspects of study quality were not assessed and the findings were not discussed in the context of study quality. It might not have been appropriate to pool the studies in a meta-analysis. Statistical heterogeneity was not assessed and there was some evidence of clinical heterogeneity. Given these limitations it is unclear whether the findings are reliable.

Implications of the review for practice and research

Practice: For patients at high risk for graft stenosis or disease progression following CABG, evaluation should not be based on ETT alone. For greater diagnostic accuracy, stress ventricular imaging should be performed alone or in addition to ETT.

Research: The authors did not state any implications for research.

Bibliographic details

Chin A S, Goldman L E, Eisenberg M J. Functional testing after coronary artery bypass graft surgery: a meta-analysis. Canadian Journal of Cardiology 2003; 19(7): 802-808. [PubMed: 12813614]

Other publications of related interest

Greenland S. Principles of multilevel modelling. Int J Epidemiol 2000;29:158-67.

Indexing Status

Subject indexing assigned by NLM

MeSH

Cardiac Catheterization; Coronary Artery Bypass /rehabilitation; Coronary Artery Disease /diagnosis /surgery; Coronary Restenosis /diagnosis; Disease Progression; Echocardiography, Stress; Exercise Test; Heart /radionuclide imaging; Heart Function Tests /methods /standards; Humans; Predictive Value of Tests; Prospective Studies; Sensitivity and Specificity; Thallium /diagnostic use

AccessionNumber

12003001515

Database entry date

31/07/2005

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.