Interventional cardiology · London
Pressure wire study (FFR / iFR), the invasive functional test that decides whether a coronary stenosis needs stenting.
A pressure wire study measures fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) across a coronary stenosis during angiography. Objectively decides whether a lesion is causing ischaemia and needs PCI, or can be treated medically.
Why patients choose us
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Interventional cardiology hands
We route you to a consultant interventional cardiologist who performs pressure-wire physiology every week — not an occasional operator.
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Decision at the table
FFR or iFR is measured in the cath lab and the PCI decision is made there and then — no repeat procedure.
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Independent, and free
We are paid by no clinic, so the recommendation is impartial and costs you nothing.
Key facts
What a pressure wire study is, and what it decides.
Six facts every patient facing a pressure wire study should know before the cath lab.
In short
FFR ≤ 0.80 or iFR ≤ 0.89 = flow-limiting. PCI at the same session.
| Fact | Detail |
|---|---|
| Definition | Invasive coronary pressure measurement across a stenosis during angiography. |
| FFR threshold | FFR ≤ 0.80 = flow-limiting lesion; PCI indicated in the symptomatic patient. |
| iFR threshold | iFR ≤ 0.89 = flow-limiting (adenosine-free, resting index). |
| Best use | Standard of care in intermediate stenoses (40–70%) on angiography. |
| Value | Reduces unnecessary PCI — many angiographically tight lesions are not ischaemic. |
| Non-invasive twin | Complements CT-FFR (HeartFlow), which does the same physiology non-invasively. |
The pathway
From consultation to physiology answer — what happens, in order.
Wire, measurement and — if needed — stent in a single cath-lab session.
Phase 1 · Before
Consultation and consent
Phase 2 · In the cath lab
Wire, measurement, decision
Phase 3 · After
Follow-up, medications
- 01
Before
Cardiology consultation
Consultant cardiologist reviews symptoms, prior imaging (CTCA, stress test) and risk factors, and confirms invasive assessment is the right next step.
- 02
In the lab
Coronary angiography under LA
Radial (wrist) or femoral (groin) access under local anaesthetic. Contrast is injected and the coronary tree mapped.
- 03
In the lab
Pressure wire passed across the stenosis
A 0.014-inch pressure-sensing wire is advanced through the guide catheter and across the target lesion.
- 04
In the lab
Adenosine (FFR) or resting measurement (iFR)
Adenosine is infused to induce maximal hyperaemia for FFR, or the resting pressure ratio is used for iFR — both take minutes.
- 05
In the lab
Pressure ratio calculated
Distal-to-proximal coronary pressure ratio calculated live in the lab — the number that drives the decision.
- 06
In the lab
PCI performed if flow-limiting
If FFR ≤ 0.80 or iFR ≤ 0.89 in a symptomatic vessel, drug-eluting stent is deployed at the same sitting.
- 07
After
Structured cardiology follow-up
Discharge medications reviewed (dual antiplatelet, statin, secondary prevention). Formal cardiology follow-up at 4–6 weeks.
What it shows
What a pressure wire actually measures.
Beyond a single FFR number — the eight measurements physiology guides.
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FFR value across a specific lesion
The single-number answer for one intermediate stenosis — ischaemic or not.
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iFR resting index
Adenosine-free alternative — comparable evidence base, avoids the hyperaemia infusion.
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Serial lesion assessment
Pullback along the vessel identifies which of two tandem lesions is truly flow-limiting.
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Left main pressure ratio
Physiological assessment of ambiguous left-main disease — a genuinely high-stakes measurement.
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Post-PCI FFR
Confirms the stent achieved a physiological result — post-PCI FFR predicts long-term outcome.
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Diffuse disease pattern
Pullback curve shows whether pressure loss is focal (stentable) or diffuse (medical).
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Microvascular dysfunction (IMR)
Index of microcirculatory resistance identifies small-vessel disease when epicardial arteries look fine.
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Red flag: FFR ≤ 0.80 in symptomatic patient — PCI at same session
The wire and the stent live in the same lab — no repeat procedure needed.
Treatment options
What the physiology answer leads to.
Eight downstream pathways — medical, interventional, and surgical.
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Optimal medical therapy (FFR > 0.80)
Lesions above threshold: antianginals, statin, antiplatelet, risk-factor control. PCI adds no prognostic benefit.
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PCI with drug-eluting stent (FFR ≤ 0.80)
Second-generation drug-eluting stent under intravascular imaging (IVUS or OCT) where indicated.
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Repeat FFR after PCI
Post-PCI physiology confirms the stent achieved its target — residual gradients predict future events.
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CABG for multi-vessel disease
Heart-team review — surgical revascularisation for left main, complex 3-vessel or diabetic patients.
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Structured cardiac rehabilitation
Supervised exercise and secondary-prevention programme improves symptoms and survival post-PCI.
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Cardiovascular risk optimisation
LDL, blood pressure, HbA1c, weight, smoking — every lever pulled hard after a positive physiology study.
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Serial follow-up with CTCA or stress imaging
Non-invasive follow-up over years to catch progression before it becomes symptomatic.
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Multi-disciplinary team review
Complex or ambiguous physiology discussed at heart-team MDT before intervention.
Our vetted London network
A small panel of cath labs, we picked them.
Interventional cardiology partners across central London, with same-session PCI and heart-team MDT.
Selection criteria
How we choose every cath lab in our network.
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Consultant interventional cardiologists with high pressure-wire volume
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Hybrid cath lab with FFR, iFR, IMR and intravascular imaging on the same console
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Same-session PCI capability with second-generation drug-eluting stents
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Structured heart-team MDT for complex or multi-vessel disease
Red flags
When physiology changes the entire plan.
Findings and complications that escalate the case — heart-team, urgent review, or a different route entirely.
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Left main FFR ≤ 0.80
Physiologically significant left-main disease is prognostic — urgent heart-team review for CABG vs PCI.
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Multi-vessel flow-limiting disease
Three-vessel disease with positive physiology in each vessel — heart-team decision, often surgical.
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Very high SYNTAX score
Anatomical complexity favours CABG over PCI regardless of physiology in many patients.
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Post-PCI stent thrombosis
Chest pain within days to weeks of stenting — emergency angiography, not a routine appointment.
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Microvascular dysfunction
IMR > 25 units — small-vessel disease with normal epicardial arteries. Different treatment pathway.
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In-stent restenosis
Recurrent angina months after PCI — physiology and imaging identify restenosis or new disease.
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Recurrent angina despite PCI
Ongoing symptoms after a physiologically successful stent — reassess for microvascular or non-cardiac cause.
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Contrast-induced kidney injury
Rising creatinine post-procedure — hydration, medication review, nephrology if severe.
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Femoral or radial access complication
Haematoma, pseudoaneurysm or radial occlusion — clinical review within 24 hours if concerns.
Reading your report
A pressure wire report can look intimidating. It isn’t.
Whatever the finding, the report keeps to the same four parts.
A quiet reminder
The report is written for your cardiologist, not for you — and that’s normal.
If you would like us to talk you through it before your follow-up, just ask.
- 01 Header
Indication and prior imaging
Symptoms, CTCA or stress imaging result, and the specific lesion targeted for physiology.
- 02 Technique
Access, wire and hyperaemic agent
Radial or femoral, wire type, adenosine dose (FFR) or resting acquisition (iFR).
- 03 Findings
FFR / iFR value, vessel and lesion
Numerical result, target vessel, pullback curve interpretation and post-PCI value if intervention performed.
- 04 Impression
The decision: read this first
Flow-limiting or not, PCI performed or deferred, medications and follow-up plan — read this first.
Frequently asked
Everything we get asked about the pressure wire study.
Quick answers on FFR vs iFR, safety, CT-FFR comparison, and what a normal result means.
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What is a pressure wire study?
An invasive test performed during coronary angiography that measures the pressure drop across a narrowing in a coronary artery. It objectively decides whether the narrowing is causing ischaemia and needs stenting, or can be treated with medication.
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What is the difference between FFR and iFR?
FFR (fractional flow reserve) requires adenosine to induce maximal blood flow and uses a threshold of 0.80. iFR (instantaneous wave-free ratio) is measured at rest, without adenosine, with a threshold of 0.89. Both have equivalent outcome evidence — the choice is operator preference and patient tolerance of adenosine.
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Why not just stent every narrowing seen on angiography?
Because up to a third of angiographically tight lesions are not actually causing ischaemia — and stenting them adds risk without benefit. Physiology-guided PCI reduces unnecessary stenting and improves outcomes.
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Is a pressure wire study safe?
It carries the same risks as coronary angiography — bruising or bleeding at the access site, contrast reaction, and rarely arrhythmia or vessel injury. Adenosine causes transient chest heaviness and breathlessness that resolves within seconds of stopping the infusion.
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How does this compare to CT-FFR (HeartFlow)?
CT-FFR uses computational fluid dynamics on a CTCA to estimate FFR non-invasively. It is the right first test for intermediate lesions on CTCA. Invasive pressure wire is used when CT-FFR is borderline, when the patient is already in the cath lab, or when PCI is planned in the same session.
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What happens if my FFR is normal?
FFR above 0.80 means the stenosis is not flow-limiting and stenting has no prognostic benefit. Treatment is optimal medical therapy — antianginals, statin, antiplatelet, and cardiovascular risk-factor control.
Sources
The guidelines behind this page.
- European Society of Cardiology. Guidelines on myocardial revascularization.
- NICE CG95. Chest pain of recent onset: assessment and diagnosis.
- American Heart Association. Scientific statements on coronary physiology.
- Cardiological Society of India. Position statements on FFR and iFR.
Reviewed 2026-07-30 by Pulse Atlas Editorial Board, . Next review 2027-07-30. Approx 6 min read.
Related tests
Looking for a different test?
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CT coronary angiography
Non-invasive CT map of the coronary arteries — the usual first step.
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CT-FFR HeartFlow
Non-invasive physiology from a CTCA — the non-invasive twin of pressure wire.
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Exercise and pharmacological stress imaging for inducible ischaemia.
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In practice, in London
The London pathway for pressure wire study
With pressure wire study, the London question is usually about report turnaround and the radiologist reading it — not whether the scan is available. On the NHS, pressure wire study typically sits behind a triage step and a wait that can stretch from a few weeks into months. In London’s private sector, the same appointment often lands within days. That speed matters when symptoms are disrupting work, sleep, or a plan you’d already committed to — and it’s the single most common reason people call us in the first place.
A typical private booking for pressure wire study in London starts with a consultant conversation — sometimes in person on Harley Street or Marylebone, sometimes on video if that suits better. Any imaging or diagnostics happen at a nearby CQC-registered facility, and reports usually land within 24 to 72 hours. The whole loop, from first call to written report, is often done inside a fortnight. For pressure wire study specifically, the difference between a routine report and a sub-speciality read is where private care earns its keep.
Where a good concierge earns its keep is in the matching. There are dozens of consultants in London who see pressure wire study — but not all of them are the right fit for every case. We narrow it down based on subspecialty, insurer coverage, the specific question being asked, and whether continuity into treatment matters. The right first appointment saves you from repeating yourself later.
Nearby in the library