Page 28 - Cardiac testing for coronary artery disease in potential kidney transplant recipients

gated the same screening test. Given that underlying prevalence in relevant populations. Table 4 summarises test performance for
of disease in a population has potential to alter diagnostic perfor- transplant candidates relative to the general population.
mance (Leeflang 2009), knowledge of the effect of clinical char- Figure 10 illustrates the applicability of our findings to clinical
acteristics such as angina or diabetes on diagnostic performance practice. Patients in the general population who present with sta-
would enable better informed decisions about screening and in- ble chest pain for assessment are typically assigned pre-test prob-
terpretation of results. Although differences in study population abilities of significant CAD of 10% to 29% (low risk), 30% to
characteristics, such as prevalence of chest pain, and test appli- 59% (intermediate risk) or 60% to 90% (high risk) determined
cation (diagnostic test threshold, criteria for positive test, choice using risk tables (NICE Clinical Guideline 1995). Given the wide
of stress agent and stress protocol, and operator variability) were heterogeneity in the estimates for both DSE and MPS, there is
likely to have contributed to heterogeneity, we were hindered in considerable uncertainty in the true post-test probabilities of each
estimating their contributions because of data paucity, which re- test. However, using the summary estimates in this review, both
sulted in low power. Consequently, we were unable to derive sum- DSE and MPS may prove useful in ruling out CAD in patients
mary measures of diagnostic performance for specific patient sub- considered to be at low risk for the condition. Patients with pos-
groups. Data that were directly comparative were limited and also itive stress test results warrant additional investigation with coro-
resulted in low power to detect important differences in accuracy nary angiography. However, the true discriminating value of both
among tests. Incomplete reporting of baseline characteristics and tests (especially DSE) is in detecting CAD in intermediate risk
study design features that are necessary for scoring methodological patients - a category that includes many potential kidney trans-
quality was a further limitation that was resolved by contacting plant recipients. Both tests help to classify patients at intermediate
study authors to obtain additional data. risk into either high or low risk categories. When DSE was used,
patients at intermediate risk of CAD who tested positive had post-
test probability of 73% to 90% (high risk) and those who tested
Applicability of findings to clinical practice and negative were downgraded to low risk (10% to 27%). Both tests,
policy
but especially DSE, have roles as triage tests for intermediate risk
Current guidelines for preoperative cardiac evaluation of trans- transplant candidates; negative results can reduce the need for fur-
plant candidates are unclear about the optimal method of assess- ther evaluation with coronary angiography. In high risk patients,
ment for potential kidney transplant recipients. Patients are often a positive non-invasive DSE or MPS test result confirms the high
referred for coronary angiography as a result of a positive non-in- risk of severe CAD, but a negative result does not conclusively
vasive screening test or deemed to be at high risk of CAD. Non-in- rule out severe CAD. These patients can be managed by being
vasive functional tests, such as DSE or MPS, have been used in the referred for coronary angiography, thus avoiding functional tests.
general population as a method of triaging patients for coronary Nevertheless, functional testing may provide additional prognos-
angiography. Results from our review provide a base to inform tic information, or help to prioritise patients waiting to be referred
clinical decision making that were derived from studies conducted for coronary angiography in resource-limited areas.

Cardiac testing for coronary artery disease in potential kidney transplant recipients (Review) 26
Copyright © 2011 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.