Feasibility and utility of anatomical and physiological evaluation of coronary artery disease with cardiac CT in severe aortic stenosis (FUTURE-AS registry)

Abstract

Background: Coronary artery disease (CAD) is common in patients with severe aortic stenosis (AS) and may impact transcatheter aortic valve replacement (TAVR) procedural and long-term outcomes. CT coronary angiography (CTA) and CT-derived fractional flow reserve (FFR_CT) are tools used to assess CAD. However, adoption in the TAVR population is hindered by safety concerns with nitroglycerin and beta-blockers. The safety, accuracy, and utility of CTA and FFR_CT optimised with these medications for TAVR have not been established.

Methods: This international, multi-center, prospective registry included severe AS patients referred for TAVR, assessed for CAD with CTA and FFR_CT. Patients all received nitroglycerin and beta-blockers as needed to optimise image quality. Severe ventricular dysfunction, recent syncope/heart failure, critical hemodynamics, or prior revascularization were excluded. Significant CAD was defined as CTA stenosis ≥50 ​% and FFR_CT≤0.75. Primary endpoint was per-patient sensitivity and negative predictive value (NPV) of CTA compared to invasive coronary angiography (ICA). Secondary endpoints included specificity and positive predictive value (PPV) of CTA and FFR_CT, safety, feasibility (non-evaluable rate), and the modelled potential of CTA ​+ ​FFR_CT to reduce pre-TAVR ICA.

Results: 327 patients (75.9 ​± ​9.7 years, 53 ​% male) underwent CTA. CTA was safe and well tolerated in nearly all patients, with transient hypotension in 4 (1.2 ​%). CTA was evaluable in 326 patients (99.7 ​%), with 9 (2.8 ​%) having a non-evaluable vessel. FFR_CT and ICA were performed in 110 (33.6 ​%) and 133 (40.7 ​%) patients, respectively. Per-patient sensitivity, specificity, NPV, and PPV of CTA were 100 ​%, 71.4 ​%, 100 ​%, and 75.9 ​% and per-vessel 82.7 ​%, 78.9 ​%, 92.3 ​%, and 59.9 ​%. FFR_CT improved specificity and PPV to 88.9 ​% and 88.0 ​% for per-patient and 95.1 ​% and 81.8 ​% for per-vessel analysis. Using a simulated triage model deferring ICA in patients with CTA <50 ​% or ≥50 ​% stenosis with FFR_CT >0.75, 267 patients (81.7 ​%) could potentially have avoided ICA.

Conclusion: Coronary CTA performed with nitroglycerin and selective use of beta-blockers is safe and effective for assessing CAD in stable severe AS patients. Combining CTA and FFR_CT enhances diagnostic accuracy, potentially reducing the need for invasive angiography and streamlining TAVR workup.

Keywords: Aortic stenosis; CT-Derived fractional flow reserve; Coronary CT angiography; Coronary artery disease; Invasive coronary angiography; Non-invasive imaging; Transcatheter aortic valve replacement.