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ACC 2017:
Round-up of key trials
by Dr Joerg Herrmann
iFR-SWEDEHEART and DEFINE-FLAIR
Two studies, one result: iFR (instant wave-free ratio)-
guided percutaneous coronary intervention (PCI), at a
threshold of 0.89, is noninferior to FFR (fractional flow
reserve)-guided PCI, at a threshold of 0.8, in terms of
key clinical endpoints (ie, major adverse cardiac events)
and is better tolerated from a patient perspective.
1–2
Both
studies also showed that FFR identified more lesions
deemed to be hemodynamically significant and led to
more interventions. The overall agreement of the two
studies is remarkable as the iFR-SWEDEHEART study
was a randomized clinical trial based on a comprehen-
sive registry
1
whereas DEFINE-FLAIR was a traditional
prospectively enrolling randomized clinical trial.
2
Most certainly, these two studies will promote the use of
iFR in clinical practice, a procedure that is much easier,
faster, and less costly to perform. An aspect challenged
by the current data is the definition of cutoffs. The best
match of iFR to an FFR value of 0.8 with a 96% sensitiv-
ity and 91% specificity is in the range of 0.85 to 0.94. A
hybrid approach has thus been advocated – that is, to
defer PCI if the iFR is greater than 0.93, to perform PCI
if the iFR is less than 0.86, and to perform FFR if the iFR
is between 0.86 and 0.93. These two studies simplified
this approach to an iFR cutoff of 0.89. Statistically, an
iFR of 0.89 matches an FFR cutoff of 0.8 only with a 73%
sensitivity and an 88% specificity, but clinically it seems
closer to 100%.
References
1. Götberg M, Christiansen EH, Gudmundsdottir IJ, et al., on behalf
of the iFR-SWEDEHEART Investigators.
N Engl J Med
DOI:
10.1056/NEJMoa1616540.
2. Davies JE, Sen S, Dehbi HM, et al.
N Engl J Med
DOI: 10.1056/
NEJMoa1700445.
SURTAVI
In August, the FDA approved the use of the bal-
loon-expandable SAPIEN 3 and SAPIEN XT valves for
transcatheter aortic valve replacement (TAVR) in inter-
mediate-risk patients. Here now comes the answer for
the self-expandable valves such as the CoreValve and
Evolute R valve in patients with severe aortic stenosis at
intermediate surgical risk (that is, those with an estimated
risk of 30-day surgical death of 3% to 15%, according
to the criteria of the Society of Thoracic Surgeons Pre-
dicted Risk of Mortality [STS-PROM]) – the SURTAVI trial.
1
The key finding is that of no difference in death from any
cause or disabling stroke at 24 months between TAVR
and surgical aortic valve replacement (SAVR); that is, the
study met its noninferiority primary endpoint. Surgery was
associated with higher rates of acute kidney injury (4.4%
vs 1.7%), atrial fibrillation (43.4% vs 12.9%), and transfusion
requirements (40% vs 12.5%), whereas TAVR patients had
a higher need for pacemaker implantation (25.9% vs 6.6%)
and higher rates of residual aortic regurgitation (75% vs
33%); however, nearly none severe, 5% moderate aortic
regurgitation – thus almost all patients were split only
between trace or mild aortic regurgitation). Paravalvular
leak was noted in 60% to 70% of TAVR patients; again,
nearly none severe, 5%moderate aortic regurgitation, and
thus almost all either only a trace or mild degree. TAVR
resulted in better aortic valve hemodynamics (greater
aortic valve area and lower aortic valve gradient) than
surgery, and neither TAVR nor surgery showed evidence
of structural valve deterioration at 24 months. Aortic valve
re-intervention rates remained low, but were 1%, 2%, and
3% at 1, 12, and 24 months in the TAVR group vs 0.2%,
0.5%, and 0.7% with SAVR.
Overall, SURTAVI results do not come as a surprise;
self-expandable TAVR is on par with SAVR with regard
Dr Herrmann, Associate Professor of Medicine at Mayo Graduate
School of Medicine in Minnesota, shares his take-home
messages from some of the key trials presented at the American
College of Cardiology’s 66th Scientific Session & Expo, 17-19
March, Washington DC, USA.
CONFERENCE COVERAGE
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PRACTICEUPDATE CARDIOLOGY