Fractional Flow Reserve Derived From Computed Tomography Coronary Angiography in the Assessment and Management of Stable Chest Pain - FORECAST

Oct 17, 2020
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Author/Summarized by Author:
Dharam J. Kumbhani, MD, SM, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
HeartFlow
Date Presented:
10/16/2020
Date Updated:
10/17/2020
Original Posted Date:
10/17/2020
References

Contribution To Literature:

The FORECAST trial showed that, compared with routine management, the use of FFRCT decreased the need for invasive angiography, but did not reduce costs; major adverse cardiac event rates were similar.

Description:

The goal of the trial was to assess the safety and efficacy of fractional flow reserve measurement based on computed tomography (FFRCT) compared with conventional management for patients with stable angina.

Study Design

Eligible patients were randomized in 1:1 fashion to either FFRCT (n = 700) or conventional management (n = 700). Patients randomized to the FFRCT arm were all referred for computed tomography coronary angiography (CTCA), and those with a coronary stenosis of ≥40% in at least one major epicardial vessel of a diameter suitable for revascularization (39%) were referred for FFRCT. In the reference arm, patients underwent the following initial investigations: invasive coronary angiography (6.7%); stress echocardiography (14.7%); nuclear perfusion scan (1.9%); CTCA (61.4%); exercise tolerance test (10.0%); stress magnetic resonance imaging (0.1%); no test (5.1%).

  • Total number of enrollees: 1,400
  • Mean patient age: 60 years
  • Percentage female: 48%
  • Percentage with diabetes: 13%

Inclusion criteria:

  • Stable angina
  • Age >18 years

Exclusion criteria:

  • No angina
  • No need for further testing
  • Prior coronary revascularization
  • Unsuitable for CTCA
  • Prosthetic valve
  • Unstable angina or acute coronary syndrome
  • New-onset atrial fibrillation

Other salient features/characteristics:

  • Proportion with FFRCT <0.8: 57%, nonanalyzable: 8.2%

Principal Findings:

The primary endpoint, use of invasive angiography for FFRCT vs. conventional management, was 19.4% vs. 25.0% (p = 0.01).

  • Median cost: £285 vs. £285 (p = 0.96)

Secondary endpoints for FFRCT vs. conventional management:

  • Major adverse cardiac events: 10.1% vs. 10.6% (p > 0.05)
  • Myocardial infarction: 9 vs. 3
  • Death: 2 vs. 0

Interpretation:

The results of this trial indicate that, compared with routine management, the use of FFRCT decreased the need for invasive angiography, but did not reduce costs; major adverse cardiac event rates were similar.

Although the PROMISE trial did not show a significant difference between anatomical versus functional imaging for stable ischemic heart disease, there is interest in combining anatomical assessment provided by CCTA with functional imaging. A post-processing technique named fractional flow reserve (FFR) by coronary CTA, or FFRCT, has been developed by HeartFlow (Redwood City, CA), which uses computational fluid dynamics applied to a standard CCTA dataset to provide FFRCT data on all major epicardial vessels. HeartFlow requires patient data transfer offsite to be post-processed by the company. This raises two limitations. First, it introduces a delay of approximately 24 hours to obtain a result. Second, it may result in Health Insurance Portability and Accountability Act (HIPAA) compliance issues.

Numerous observational studies suggested that FFRCT may be safe and cost-effective. This is one of the only randomized trials on this topic, and suggests that it is not necessarily better in terms of resource utilization compared with conventional management. Although no differences were noted in clinical endpoints, the trial was underpowered to detect meaningful clinical differences.

References:

Presented by Dr. Nick Curzen at the Transcatheter Cardiovascular Therapeutics Virtual Meeting (TCT Connect), October 16, 2020.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Stable Ischemic Heart Disease, Cardiac Surgery and SIHD, Interventions and Imaging, Angiography, Computed Tomography, Echocardiography/Ultrasound, Magnetic Resonance Imaging, Nuclear Imaging, Chronic Angina

Keywords: Angina, Stable, Coronary Angiography, Coronary Stenosis, Cost-Benefit Analysis, Diagnostic Imaging, Echocardiography, Stress, Exercise Test, Fractional Flow Reserve, Myocardial, Magnetic Resonance Imaging, Myocardial Infarction, Myocardial Ischemia, Myocardial Revascularization, Tomography, X-Ray Computed, TCT20, Transcatheter Cardiovascular Therapeutics


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