Coronary CTA Demonstrates High Burden of Coronary Artery Disease Despite Low Risk Nuclear Studies in Pre‐Liver Transplant Evaluation

BACKGROUND AND AIM We investigated the presence and severity of CAD in orthotopic liver transplant (OLT) candidates using coronary artery calcium score (CACS) and coronary computed tomography angiography (CTA) as compared with the prevalence of normal and abnormal single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). METHODS 140 prospective OLT candidates without known CAD underwent CAC with or without CCTA (n=77) and FFRCT (n=57) using a dual source CT and were followed for 2.6 ± 1.4 years. Coronary plaque was quantified using the segment-involvement score (SIS) and segment stenosis score (SSS). Providers were blinded to CT results unless high risk CAD was identified. Correlation with SPECT MPI and coronary angiography was performed when available. RESULTS The mean age was 59 ± 6 years and 65.0% of patients were male. Etiology of ESLD was alcohol and/or HCV in 55.7%. Mean CACS was 367 ± 653 and only 15.0% had CACS of 0. 83.6% had a SPECT MPI performed, of which 95.7% were interpreted as normal/probably normal. 9.1% had obstructive CAD (≥ 70% stenosis), 67.5% non-obstructive CAD, and 23.4% had no CAD by Coronary CTA. Non-obstructive CAD was diffuse with mean SIS 3.0 ± 2.9 and SSS 4.5 ± 5.4. High-risk findings were only found in 11 patients (7.9%) (severe 3 vessel CAD n=4, CAC>1000 n=7) prompting x-ray angiography in 3 patients who had undergone coronary CTA, and resulting in revascularization of a high risk obstruction in one subject who had a normal SPECT study. CONCLUSIONS Patients with ESLD have a high prevalence of non-obstructive CAD by CTA which is undiagnosed by SPECT MPI which was normal in nearly all patients, potentially underestimating cardiovascular risk. Deferring x-ray angiography unless high-risk coronary CTA findings are present is a potential strategy for avoiding unnecessary x-ray angiography.