MedicalResearch.com Interview with:
Dr. Justin Davies PhD
Senior Reserch Fellow and Hononary Consultant Cardiologist
National Heart and Lung Institute,
Imperial College London
MedicalResearch.com: What is the background for this study?
Response: We know from the FAME study that compared to angiography alone, FFR guided revascularization improves long-term clinical outcomes for our patients. Despite this, adoption of FFR into everyday clinical practice remains stubbornly low. One major factor for this is the need for adenosine (or other potent vasodilator medications) in order to perform an FFR measurement. Adenosine is expensive, unpleasant for the patient, time consuming and even potentially harmful.
iFR is a newer coronary physiology index that does not require adenosine for its measurement. In the prospective, multi center, blinded DEFINE FLAIR study, 2492 patients were randomly assigned to either FFR guided revascularisation or iFR guided revascularization and followed up for a period of 1 year.
MedicalResearch.com: What are the main findings?
Response: The main findings of the study were that at 1 year, iFR and FFR performed equally well with respect to major adverse cardiac events (MACE). Furthermore, patients allocated to the iFR arm had a proportionally lower need for PCI, with fewer stents deployed when PCI was indicated. Furthermore, iFR measurements were performed significantly quicker and with significantly fewer side effects for the patient.
MedicalResearch.com: What should readers take away from your report?
Response: We should take away from this study that both iFR and FFR perform equally well when used to guide revascularization decision-making in the cath lab. We can also take away the potential benefits iFR offers over FFR with regards to time savings, patient experience and likely decreased healthcare costs owing to a reduction in over need for PCI (without any decrease in safety).
Overall, we hope that readers will appreciate that iFR offers an adenosine free approach to ischaemia guided revascularization, thereby removing one of the last remaining major barriers to the uptake of coronary physiology.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: The DEFINE FLAIR study provides robust evidence of the safety of an iFR only approach to revascularisation decision making. However, there still remains a number of unanswered questions for the field of coronary physiology.
A prime example would include how to manage bystander disease during ACS, which may inherently be more accurate using an adenosine free approach. Furthermore, the use of extended applications of iFR such as iFR Scout technology (which allows the individual pressure gradients to be quantified in tandem or diffuse disease) will be an area of great interest in future research.
MedicalResearch.com: Is there anything else you would like to add?
Response: We are very excited about iFR Scout technology, which provides real-time co-registration between the angiogram image and pressure loss along the length of a vessel. iFR Scout also allows for virtual PCI to be performed. This transforms PCI decision making from ‘vessel level’ to ‘stenosis level’.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Citation: NJEM and ACC 2017
Use of the Instantaneous Wave-free Ratio or Fractional Flow Reserve in PCI
March 18, 2017DOI: 10.1056/NEJMoa1700445
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