INCREMENTAL PROGNOSTIC VALUE OF ADENOSINE STRESS MYOCARDIAL PERFUSIONSINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY AND IMPACT ON SUBSEQUENT MANAGEMENT IN PATIENTS WITH OR SUSPECTED OF HAVING MYOCARDIAL-ISCHEMIA

We examined 1,159 consecutive patients who underwent adenosine stress dual isotope single-photon emission computed tomography (SPECT) and ha d follow-up performed at a mean of 27.5 +/- 9.1 months (94% complete) for hard events (cardiac death and myocardial infarction) and referral to cardiac catheterization after nuclear testing. During follow-up, 1 20 hard events occurred (11.0% hard event rate; 72 cardiac deaths [6.7 % cardiac death rate] and 57 myocardial infarctions [5.3% myocardial i nfarction rate]). Cox proportional hazards analysis revealed that nucl ear testing added incremental value after adjusting for clinical and h istorical variables (global chi-square increased 13 to 98 for cardiac death as the end point, global chi-square increased 19 to 105 for hard events as the end point; p < 0.0001 for both). Kaplan-Meier analysis demonstrated that after clinical risk stratification of the patient po pulation, the results of nuclear testing were further able to signific antly stratify both low-and intermediate-to high-risk patients. Patien ts with both normal and mildly abnormal scans were at low risk of card iac death (< 1% cardiac death per year of follow-up) and the risk of e vents increased significantly with worsening scan result. Multivariabl e analysis revealed that the only predictor of referral to catheteriza tion was the extent and severity of reversible defect present on the s can. Referral rates to early catheterisation were very low in patients with normal scans and increased significantly as a function of worsen ing ran results. In patients who underwent myocardial perfusion SPECT using adenosine stress, the results of nuclear testing yielded increme ntal prognostic information and clinically relevant risk stratificatio n. Referring physicians predominantly utilized nuclear information whe n referring patients to catheterization after nuclear testing and do s o at rates comparable with those after exercise SPECT despite the high er risk of events in patients undergoing pharmacologic stress. (C) 199 7 by Excerpta Medica, Inc.