76 Use of non-invasive cardiac testing prior to referral for invasive coronary angiography in patients presenting with stable chest pain in a large district general hospital

Introduction The Cardiac Catheterisation Laboratory receives a high volume of referrals for outpatient, invasive coronary angiography (iCA) for suspected coronary artery disease (CAD). iCA may be requested for diagnostic and therapeutic purposes i.e. percutaneous coronary intervention (PCI) or CABG. NICE guidance recommends the use of non-invasive anatomical and/or functional testing (i.e. CT coronary angiography and/or non-invasive stress testing) prior to iCA for the assessment and diagnosis of stable chest pain with a suspected cardiac origin, also known as chronic coronary syndrome (CCS). Aims The aim of the study is to determine Catheter Laboratory utilisation through referrals for iCA. To identify the proportion of patients who undergo prior non-invasive cardiac testing for suspected CCS as per NICE CG95 guidance and to establish revascularisation rates among this patient cohort compared to those who did not undergo prior non-invasive testing. Methods Retrospective single-centre cohort study of 161 patients referred for iCA between April and September 2022. Patient records obtained from Catheter Laboratory booking records were analysed for age, demographics, indication for iCA, cardiovascular risk factors, prior non-invasive testing, iCA findings and interventions. Primary outcome was revascularisation intervention (either PCI or cardiac surgical referral) in the patient cohort undergoing prior non-invasive testing. Secondary outcomes included the severity of CAD associated with prior non-invasive testing and number of patient co-morbidities. Results 161 patients referred for iCA over a 6-month period with a mean age of 69 ± 10.0 years. Referral for suspected CCS (27%, 44/161), presenting with typical and/or atypical chest pain and risk factors for CAD, was the single most common reason for iCA referral. This was followed by surgical work up for valvular heart disease (20%, 33/161). 95 patients were referred for potential revascularisation. Of those, 63 underwent prior non-invasive testing and 32 were referred without any prior testing. 56% (35/63) of patients with prior non-invasive testing underwent revascularisation compared to 28% (9/32) who did not, this is statistically significant (Fisher's exact test (p 0.0163)). (Figure 1) Individuals that have prior non-invasive testing are significantly more likely to go on to have revascularisation with an odds ratio of 3.19 (C.I 1.29 to 7.46) compared to those without. The use of prior non-invasive testing was associated with more severe CAD compared to the group who did not undergo prior non-invasive testing (73% v 27%, p 0.19). Prior non-invasive testing was therefore associated with more severe CAD however, this was not statistically significant. 59% of patients with 3 or more co-morbidities (IHD, HTN, hypercholesterolaemia, CKD, prior stroke, atrial fibrillation/flutter) had severe CAD. Conclusion Non-invasive testing prior to iCA is more likely to result in revascularisation (pConflict of Interest None