Clinical Trial Details
— Status: Recruiting
Administrative data
| NCT number |
NCT04417634 |
| Other study ID # |
2020-1 |
| Secondary ID |
|
| Status |
Recruiting |
| Phase |
Phase 4
|
| First received |
|
| Last updated |
|
| Start date |
May 10, 2020 |
| Est. completion date |
June 10, 2025 |
Study information
| Verified date |
September 2023 |
| Source |
Johannes Gutenberg University Mainz |
| Contact |
Tommaso Gori |
| Phone |
+491721052846 |
| Email |
tomgori[@]hotmail.com |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The aim of this study is to record hemodynamic pullback information using continuous resting
full-cycle flow ratio (RFR) and fractional flow reserve (FFR) in patients with diffuse
coronary artery disease. The capacity of the two indexes to predict the hemodynamic outcome
after stenting will be compared.
Goals of the study are:
- To study the accuracy of RFR/FFR gradients in predicting the change in whole-vessel
RFR/FFR after PCI.
- To identify a threshold in the RFR/FFR gradient that is predictive of pathological
RFR/FFR also after the PCI of the first lesion.
Description:
The study of the hemodynamic relevance of coronary stenoses is a well-validated method to
identify coronary lesions to be treated. A number of studies show that FFR-guided PCI is
superior to angiography guided PCI2-4. The achievement of maximal hyperemia is a prerequisite
for FFR measurements. Hyperemia is usually achieved with the intravenous or intracoronary
infusion of adenosine, which requires time and is potentially associated with discomfort for
the patient. To avoid this, resting indexes have been developed. The instantaneous flow
reserve (iFr) was the first of these indexes, and two large studies have shown that this
parameter is non-inferior to FFR in terms of patient prognosis5. More recently, a number of
other parameters have been developed, among which the RFR (resting flow ratio), which can be
measured with the same intracoronary wire as the FFR and therefore requires no additional
procedures. Studies show that these methods are equivalent6. The advantage of these resting
indexes (which are all included in the most recent AHA/ACC guidelines7, 8), is that they do
not require hyperemia. This might represent a particular advantage in the setting of tandem
stenoses or diffuse disease. Since hyperemic flow in a vessel is limited by each one of the
stenoses present in that vessel, each individual stenosis limits the capacity of FFR to
assess the hemodynamic relevance of the other ones. In other words, invasive measurements of
coronary hemodynamics using FFR in the setting of diffuse or tandem lesions are complicated
by the fact that maximal hyperemia cannot be achieved, which limits the capacity of FFR to
assess the hemodynamic relevance of individual focal stenoses. In this setting, the usual
binary system (FFR < or > 0.80) cannot be easily applied.
This limitation is independent of the sequence of the stenoses: proximal lesions limit the
reliability of FFR measurements in distal stenoses and vice versa (as long as no significant
side branches are present between the two lesions). Since hyperemic flow declines
significantly as soon as a 50% reduction in lumen diameter is present, even apparently
non-relevant lesions may compromise any assessment based on hyperemia. This phenomenon,
called hemodynamic interdependence of stenoses under conditions of hyperemia represents a
significant limitation that applies to FFR but not to hyperemia-free indexes.
In order to address this issue in routine practice, FFR is measured first, then a pullback is
performed and the lesion/segment where the pullback identifies the highest gradient is
treated first. The removal of this stenosis increases maximal achievable hyperemic flow, thus
increasing the significance of the remaining lesions. FFR is then measured again to test the
hemodynamic significance of the other stenoses at a higher level of hyperemia. The capacity
of FFR to predict whether removal of the first stenosis will be associated with the
normalization of FFR is very limited, which requires that FFR be measured multiple times,
prolonging the procedure and increasing the discomfort for the patient.
When studying coronary stenoses, the advantage of resting hemodynamic indexes is that
non-critical stenoses (ie below 90%) do not modify resting blood flow. Because resting flow
is more constant, and the effect of PCI is minimal, resting pressure changes measured across
sequential lesions are likely to be more predictable.The hypothesis of the study is that, as
compared to FFR, RFR will provide a better estimate of post-PCI hemodynamic outcomes.
