Influence of updated guidelines on short- and long-term mortality in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS)

Aim: In 2002 the ACC/AHA guidelines for the management of patients with unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI) were updated. We aimed to answer whether the implementation of updated guidelines was capable of influencing short- and long-term mortality in these patients.

Methods: We analyzed data on 812 consecutive patients who were admitted with either UA or NSTEMI between 2001 and 2004. Patients admitted in the two years before the implementation of updated guidelines (UA(01/02) group and NSTEMI(01/02) group) were compared to patients admitted in the two years thereafter (UA(03/04) group and NSTEMI(03/04) group). Yearly follow-up concerning all-cause mortality was obtained up to four years.

Results: The rate of revascularizations, the percentage of procedures performed within 48 h of admission, and the administration of clopidogrel increased significantly. However, still many - especially high-risk - patients did not receive revascularization. Patients of both UA groups had an identical in-hospital mortality rate. Differences in mortality between groups gained statistical significance over time (four-year mortality; 15.1% for the UA(03/04) group vs. 26.5% for the UA(01/02) group, p=0.014; HR 0.49 95% CI 0.28-0.87). In patients with NSTEMI in-hospital mortality decreased from 18.4% in the NSTEMI(01/02) group to 9.6% in the NSTEMI(03/04) group (p=0.011; HR 0.47 95% CI 0.26-0.84), and 1-year mortality from 34.7% to 25.1% (p=0.038; HR 0.63 95% CI 0.41-0.98), respectively. Mortality rates beyond one year were still lower in the NSTEMI(03/04) group as compared to the NSTEMI(01/02) group but it did not reach statistical significance. Multivariate Cox-regression analysis revealed furthermore that also patients with higher age and/or renal dysfunction benefit from an early invasive strategy.

Conclusion: The implementation of updated guidelines for NSTE-ACS had significant impact on short- and long-term mortality. However, an early invasive strategy is still withheld to a significant number of high-risk patients, who would benefit from an invasive treatment.