Impact on stable chest pain pathways of CT fractional flow reserve.

Abstract

To evaluate the impact of introducing CT fractional flow reserve (FFR_CT) on stable chest pain pathways, concordance with National Institute for Health and Care Excellence (NICE) chest pain guidelines, resource usage and revascularisation of patients from a tertiary UK cardiac centre rapid access chest pain clinic (RACPC). Single-centre before and after study comparing data from electronic records and Strategic Tracing Service of all RACPC patients attending between 1 July 2017 and 31 December 2017, and 1 August 2018 and 31 January 2019. Two hundred and sixty-eight and 287 patients (overall mean age 62 years, range 26-89 years, 48.3% male), were eligible for first-line CT coronary angiography (CTCA) pre-FFR_CT and post-FFR_CT, respectively. First-line CTCA use per NICE Guideline CG95 increased (50.6% pre-FFR_CT vs 75.7% post-FFR_CT, p<0.001). More patients reached pathway endpoint (revascularisation or assumed medical management) after one investigation (74.9% pre-FFR_CT vs 84.9% post-FFR_CT, p=0.005). There were fewer stress (22.8% pre-FFR_CT vs 7.7% post-FFR_CT, p<0.001) and rest (10.4% pre-FFR_CT vs 4.2% post-FFR_CT, p=0.007) myocardial perfusion scans and diagnostic-only angiograms (25.5% vs 13.7%, p<0.001). Despite fewer invasive procedures (29.3% pre-FFR_CT vs 17.6% post-FFR_CT, p=0.002), revascularisation rates remained similar (10.4% pre-FFR_CT vs 8.8% post-FFR_CT, p=0.561). Avoiding invasive investigations reduced inpatient admissions (39.0% pre-FFR_CT vs 24.3% post-FFR_CT, p<0.001). Time to revascularisation was unchanged (153.5 days pre-FFR_CT vs 142.0 post-FFR_CT, p=0.925). Unplanned hospital attendances, emergency admissions and adverse events were similar. FFR_CT adoption was associated with greater compliance with NICE guidelines, reduced invasive diagnostic angiography, planned admissions and needing more than one test to reach a pathway endpoint.