Assessing the effect of publication of clinical guidelines on the management of unstable angina and non-ST elevation myocardial infarction in the TIMI III (1990-1993) and the GUARANTEE (1995-1996) Registries.

Background: The clinical guidelines for unstable angina (UA) and non-ST elevation myocardial infarction (NSTEMI) published in 1994 by the Agency for Health Care Policy Research (AHCPR) were intended to help improve treatment. No large study, however, has evaluated the effect of the guidelines on clinical practice

Methods: We compared the treatment of 3,318 patients admitted with UA/NSTEMI in the preguideline Thrombolysis in Myocardial Infarction (TIMI) III Registry (1990-1993) and 2,948 patients enrolled in the postguideline Global Unstable Angina Registry and Treatment Evaluation (GUARANTEE) Registry (1995-1996).

Results: More patients in GUARANTEE received guideline-recommended medication than did those in TIMI III, specifically beta-blockers (50.9% vs. 40.7%, P < 0.001), heparin (63.3% versus 57.5%, P < 0.001), and the combination of aspirin, heparin, and beta-blockers on admission plus aspirin at discharge (26.9% vs. 18.8%, P < 0.001). These changes were similar in all subgroups, but the greatest improvement in medication use was seen in patients admitted to a tertiary care hospital and in those with a final diagnosis of NSTEMI, i.e., with positive cardiac markers. Conversely, fewer patients in GUARANTEE who fulfilled AHCPR criteria for catheterization underwent the procedure (62.3% in GUARANTEE tertiary centers vs. 44.6% in GUARANTEE nontertiary centers vs. 66.0% in TIMI, P < 0.001).

Conclusion: After publication of clinical guidelines for UA/NSTEMI, more patients received appropriate pharmacologic treatment, but a significant number of patients remained under-treated. Efforts to improve compliance with guideline recommendations via education and critical pathways are warranted, especially in nontertiary care settings.