Dedicated Cardiovascular Computed Tomography as a Gatekeeper to Invasive Angiography in Real World Clinical Practice [Conference Winner Abstract]

Introduction With technological advances and increasing study data cardiovascular computed tomography angiography (CCTA) became first line assessment for coronary artery disease (CAD) and is considered a gatekeeper to invasive coronary angiography (ICA) with an excellent negative predictive value [1-3]. Yet, the specificity of obstructive CAD (defined as stenosis ≥70 %) on CCTA is 50-70 % when compared to ICA [1-3]. We hypothesized that installing a dedicated CCTA department and improving CCTA technology may be associated with better image quality leading to an increase in CCTA specificity. Moreover, an additional review of obstructive CAD on CCTA may improve CCTA accuracy. Aim To evaluate the specificity of CCTA before and after installation of a dedicated CCTA department and to analyze the results of the additional review of obstructive CCTA cases. Methods The results of ICA performed in a one-day inpatient clinic were analyzed over two two-month periods: January– February 2023 (Period 1) and November–December 2023 (Period 2) corresponding with installation of a new CCTA department in October 2022 (CCTA waiting time approx. 6 months). Prevalence of non-obstructive CAD (<50 % stenosis), the proportion of patients who underwent CCTA before ICA and the per-patient specificity of CCTA were evaluated. From February to May 2024, all CCTA cases with obstructive CAD were reviewed by a team of interventional and imaging specialists, and patients with left main or proximal epicardial stenoses after discussion with the treating cardiologist were referred for an expedited ICA. CCTAs were performed with Canon Aquilion One 320 slice 0.36 s rotation scanner (Period 1) that was upgraded to Canon Aquilion One Genesis 320 slice 0.27 s rotation scanner (Period 2). Categorical variable analysis was performed using the χ² test (p < 0.05) Results During Periods 1 and 2, a total of 340 and 400 ICAs were performed, respectively. Pre-ICA CCTA was performed in 19.1 % and 24.3 % of patients, respectively (p = 0.048). The prevalence of non-obstructive CAD among patients undergoing ICA was 53.3 % in Period 1 and 41.2 % in Period 2 (p=0.0015). The specificity of CCTA for detecting obstructive CAD was approx. 70 %. From February to May 2024, 2128 CCTA scans were performed. Of these, 14.1 % (n = 301) were classified as CAD-RADS 4A, 4B, or 5. A total of 119 patients (39.5 %) were referred for expedited ICA. Among these patients, significant coronary artery stenosis (>70%) was identified in 97 cases (81.5 %). Ad hoc percutaneous coronary intervention (PCI) was performed in 37 patients (32 %), two-staged PCI in 31 patients (38.1 %) and 24 patients were referred to the Heart Team (24.7 %) Conclusions CCTA was performed in less than a third of patients referred for ICA. Over half of the patients referred for an ICA had nonobstructive CAD and could have benefited from a CCTA. Expedited ICA approach for high risk severe stenoses on CCTA resulted in marginally higher CCTA specificity.