A systematic review of Appropriate Use Criteria for transthoracic echocardiography: are they relevant outside the United States?

Introduction: The 2011 Appropriate Use Criteria (AUC) were developed by the American Society of Echocardiography (ASE) to provide guidance for referring physicians in response to growing concerns about unnecessary transthoracic echocardiogram (TTE) requests. Very few studies have assessed how medical centers overseas perform against AUC. Evidence is now emerging that inappropriate referral rates in Europe are similar to those reported in the US.

Objective: This study systematically reviewed published evidence to identify (1) whether the 2011 AUC are applicable to medical centers outside the US (2) the level of adherence to the AUC across multiple centers, (3) the main factors which cause deviation from AUC, (4) any changes in referral rates since the publication of AUC, and (5) any factors and/or intervention strategies which promote adherence to AUC.

Methods and results: Electronic databases were systematically searched for papers related to AUC and cardiac imaging. Following screening and application of eligibility criteria, data was extracted from ten reports involving 8561 TTE studies. Classification rates were 99.5 and 98% for US studies and studies outside the US respectively. Overall, 7119 TTE studies were classified as appropriate (83.1%) of which 3724 were US referrals (84.7%) and 3395 originated outside the US (81.5%). Six of the included studies independently observed significantly more appropriate referrals among inpatients compared to outpatients (p < 0.001). US centers observed no significant difference in appropriate referral rates between physician specialties while one UK study showed cardiac surgeons ordered inappropriate TTEs more frequently than other specialties (p < 0.05). This review found no obvious trend in appropriate referral rates between 2012 and 2015 indicating no temporal change in physician ordering patterns. Only one educational interventional study met the author's criteria which showed that while intervention was effective during its implantation (26% reduction in TTEs ordered per day), TTE referral rates regressed to pre-intervention levels overtime.

Conclusions: In conclusion, the American guideline AUC are applicable to centers outside the US and their implementation across five international centers suggest almost 1 in 5 scans could be avoided.