RELATIVE EFFECTIVENESS OF 4 PREOPERATIVE TESTS FOR PREDICTING ADVERSECARDIAC OUTCOMES AFTER VASCULAR-SURGERY - A METAANALYSIS

Various noninvasive tests have been proposed to stratify perioperative cardiovascular risk, including dipyridamole thallium scintigraphy (DT S), ejection fraction estimation by radionuclide ventriculography (RNV ), ischemia monitoring by ambulatory electrocardiography (AECG), and d obutamine stress echocardiography (DSE). Which of these tests is most effective for predicting adverse perioperative cardiac outcome? To ans wer this question, and also to stimulate future studies, we evaluated 56 studies examining one or more of the four tests. We conducted meta- analysis on 20 studies that met the inclusion criteria. Outcome measur es evaluated were cardiac death or myocardial infarction occurring dur ing hospital stay or within 1 mo after surgery. Relative risk (RR), wh ich is the probability of adverse cardiac outcome when the test is pos itive divided by the probability of adverse outcome when the test is n egative, was used to combine evidence from different studies. An empir ical Bayes procedure with a normal-normal hierarchic model was then us ed to obtain a meta-analytic confidence interval for the overall media n of the relative risks. The between-study variance was estimated usin g the method of moments approach described by DerSimonian and Laird (C ontrolled Clin Trials 1986;7:177-88). Combined (median) RR [95% confid ence interval (CI)] and the number of studies included in our meta-ana lysis for different evaluative tests were as follows: DTS 4.6 (2.1-10. 4) (n = 6); RNV 3.7 (1.6-8.3) (n = 5); AECG 2.7 (1.4-5.1) (n = 6), and DSE 6.2 (1.7-22.8) (n = 3). We conclude that while DTS, RNV,AECG, and DSE are effective (the 95% CIs are greater than 1.0) in predicting th e cardiac outcome after vascular surgery, the data are not definitive in determining the optimal test (95% CIs for RR overlap). Future studi es should include DSE, as this test. shows great promise for predictin g adverse cardiac events after vascular surgery.