Estimating the clinical effectiveness of virtual fractional flow reserve (vFFR) and its potential impact upon the quality of life and costs of treatment in coronary artery disease

Background:
Invasive (measured) fractional flow reserve (mFFR) is a pivotal tool for evaluating and directing management strategies for moderate coronary artery disease (CAD); however, its utilisation in clinical practice is limited due to its invasive nature, expense, and time constraints. Virtual FFR (vFFR) computed from the coronary angiogram (CAG) can be performed without needing a pressure wire or hyperaemia induction. Whilst vFFR is gaining clinical effectiveness data, little is known about its cost-effectiveness and implications for quality of life (QOL). In the VIRTU-4 study, patients with acute and chronic coronary syndromes underwent CAG and vFFR assessment. Their management plan was made on the basis of the CAG, and any potential (virtual) change after vFFR was documented.
Hypothesis:
Management plans based upon vFFR will lead to important potential changes in cost-effectiveness and QOL compared to those based upon coronary angiograms only at 12 months.
Methods:
Patients in VIRTU-4 were contacted at one year for clinical endpoints, including all-cause mortality, myocardial infarction, stroke, hospital re-admissions, repeat revascularisations, outpatient attendances and cardiac rehabilitation. Data on quality of life (EQ-VAS and EQ-indexed scores), NYHA and CCS classes at one-year follow-up were gathered. Total costs incurred were calculated. Patients who experienced a virtual change in management plan following vFFR disclosure underwent review in two independent expert MDTs to predict virtual changes in the actual outcomes if vFFR-based plans had been followed. The clinical and economic implications of these changes were estimated, guided by available literature.
Results:
Of 308 patients in VIRTU-4, 266 were contactable at one year. There were seven deaths, five MIs, and three strokes. In the ACS cohort, there were 32 cardiac re-admissions and five repeat revascularisations, and in the CCS cohort, 25 cardiac re-admissions and seven revascularisations. There was no statistically significant difference in patients' QOL at 12 months compared to baseline. However, QOL parameters demonstrated improvement after excluding non-cardiac factors. 65/266 patients (24.4%) had a virtual change in management plan after vFFR disclosure. vFFR-based treatment decisions would have saved 26 invasive pressure wire assessments. Within the ACS group, 17/39 patients (43.5%) treated with PCI would have received conservative treatment, whereas in the CCS group, 13/26 patients (50%) who received conservative treatment would have undergone PCI. vFFR-guided plans would have resulted in an average virtual increase in the cost of £60 per patient in the virtual change subset (n=65), comprising a saving of £163 per patient in the ACS group and an extra spend of £395 per patient in the CCS group. vFFR guidance could have led to a virtual increase in QOL scores for ACS patients by 0.3% in EQ-VAS (p=0.96) and 0.1% in EQ-indexed scores (p=0.96). For CCS patients, vFFR could have resulted in a virtual increase of 6.7% in EQ-VAS (p=0.02) and 5% in EQ-indexed scores (p=0.03). When factoring in the cost of a vFFR licence to the total annual costs, the ICER remained well below the willingness-to-pay (WTP) threshold for the UK, demonstrating the cost-effectiveness of vFFR+CAG compared to CAG-only. The ICERs were £2803, £4077, and £6626 per QALY for voucher-based licence costs of £50, £100, and £200 per patient, respectively. Similarly, with an institutional license, the ICERs were £4077, £5352, and £7901 per QALY for annual license tariffs of £20,000, £30,000, and £50,000, respectively.
Conclusions:
Incorporating vFFR into revascularisation plans for coronary artery disease (CAD) not only resulted in a change of management plans in one-fifth of cases but could also offer potential clinical and economic benefits over conventional CAG, with trivial additional net costs.