Thread by @SukhNijjer

FFR in ACS? Should we stop doing it now that FLOWER-MI shows no apparent benefit. Good question from @drgprman. It's another French study casting some doubt over FFR in ACS, FUTURE being the first). Let's go through the previous data, as there are other FFR studies in ACS 1/x

Why the interest in FFR in ACS? Much of our work is now ACS patients so natural to ask if we can translate the success of FFR in stable patients into the ACS cohort.

Well, no data for the culprit in STEMI: get that vessel open!

However, in STEMI we find 30-50% of patients have multi-vessel disease and 70% of these have intermediate disease. Can we measure FFR in those patients? Does the FFR change? Let's look at this case. 1 week the LAD is now strongly positive! What happened?

Let's look at the prior studies using FFR in multi-vessel disease in patients with STEMI. DANAMI-PRIMULTI is similar sized to FLOWER; both it and COMPARE-ACUTE showed complete Revasc guided by FFR was better than Culprit only. But unblinded & driven by revasc decisions!

What about FFR in NSTEMI patients? Observational studies have repeatedly shown MACE rates in patients managed with FFR are consistently higher than similar patients with stable disease. Seen in FAME & DEFINE-FLAIR. FAMOUS-NSTEMI showed higher revasc if deferred.

So we have a consistent message across these studies. FFR in ACS: deferral based on standard cut-points leads to higher MACE rates - likely because the pathology is different. Plaque rupture in result in 'milder' stenoses which may not generate classical ischaemia.

And now onto more recent studies: COMPLETE demonstrated improved outcomes with aggressive revascularisation & had trivial use of FFR. FLOWER shows a divergence in MACE-free survival - all driven by Revasc. But we need to know if this in the deferred lesions/ vessels.

More studies are on the way. iSTEMI showed iFR can be measured at time of STEMI and values are reproducible at interval repeat Cath. iModern looks at iFR assessment at the time of STEMI vs revise driven by Stress Perfusion CMR - results are pending.