Adherence to Cardiac Practice Guidelines in the Management of Non-ST-Elevation Acute Coronary Syndromes: A Systematic Literature Review.

Background: In the management of non-ST-elevation acute coronary syndrome (NSTACS) a gap between guideline-recommended care and actual practice has been reported. A systematic overview of the actual extent of this gap, its potential impact on patient-outcomes, and influential factors is lacking. Objective: To examine the extent of guideline adherence, to study associations with the occurrence of adverse cardiac events, and to identify factors associated with guideline adherence. Method: Systematic literature review, for which PUBMED, EMBASE, CINAHL, and the Cochrane library were searched until March 2016. Further, a manual search was performed using reference lists of included studies. Two reviewers independently performed quality-assessment and data extraction of the eligible studies. Results: Adherence rates varied widely within and between 45 eligible studies, ranging from less than 5.0 % to more than 95.0 % for recommendations on acute and discharge pharmacological treatment, 34.3 % - 93.0 % for risk stratification, and 16.0 % - 95.8 % for performing coronary angiography. Seven studies indicated that higher adherence rates were associated with lower mortality. Several patient-related (e.g. age, gender, co-morbidities) and organization-related (e.g. teaching hospital) factors influencing adherence were identified. Conclusion: This review showed wide variation in guideline adherence, with a substantial proportion of NST-ACS patients possibly not receiving guideline-recommended care. Consequently, lower adherence might be associated with a higher risk for poor prognosis. Future research should further investigate the complex nature of guideline adherence in NST-ACS, its impact on clinical care, and factors influencing adherence. This knowledge is essential to optimize clinical management of NSTACS patients and could guide future quality improvement initiatives.