Impact of appropriateness in clinical practice: data from a single-centre nuclear cardiology laboratory

Aims: To verify the level of appropriateness of referral to our nuclear cardiology laboratory for stress myocardial perfusion imaging (MPI) and explore the correlation between test appropriateness patterns and ischaemia. Methods and results: In 1870 consecutive patients (mean age 73 ± 12 years; 33% female) undergoing MPI, the level of imaging test appropriateness was evaluated according to the 2023 Appropriate Use Criteria (AUC) and the current European Society of Cardiology (ESC) guidelines for the management of chronic coronary syndromes. The evidence of moderate-to-severe ischaemia (i.e. summed difference score >7) was recorded. According to the AUC criteria, the MPI of 1638 (88%), 130 (7%), and 102 (5%) patients could be classified as ‘appropriate’, ‘inappropriate’, and ‘uncertain’, respectively. Similarly, in 1685 (90%) patients, the referral to MPI was adherent to ESC guidelines, while in 185 (10%), it was not. The majority of appropriate MPI tests showed the presence of moderate-to-severe ischaemia (55%), while only a limited number (10%; P < 0.05) of MPI tests with uncertain clinical appropriateness or clearly inappropriate indications did not. In patients managed adherently to ESC guidelines, invasive coronary angiography more frequently showed obstructive coronary artery disease (CAD) (93 vs. 47%, P < 0.001) and led to coronary revascularization (65 vs. 23%, P < 0.001) compared with patients managed non-adherently. Conclusion: In a single-centre, single-national, single-modality population, the current rate of appropriate MPI tests is high. Appropriate referrals are associated with a higher probability of moderate-to-severe ischaemia and better downstream resource utilization than inappropriate ones.