Clinical Trial Details
— Status: Active, not recruiting
Administrative data
NCT number |
NCT03030495 |
Other study ID # |
IMPACT16453143 |
Secondary ID |
|
Status |
Active, not recruiting |
Phase |
|
First received |
|
Last updated |
|
Start date |
December 2016 |
Est. completion date |
December 31, 2024 |
Study information
Verified date |
April 2024 |
Source |
Samsung Medical Center |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Observational [Patient Registry]
|
Clinical Trial Summary
1. To compare the risk of atherosclerotic lesion progression and subsequent
patient-oriented composite outcomes (all-cause mortality, any MI, or any Ischemia-driven
repeat revascularization) between deferred lesions with or without over microvascular
disease, defined as physiological classification
2. To explore independent predictors of atherosclerotic lesion progression in deferred
lesions based on fractional flow reserve-guided strategy and treated by contemporary
medical treatment
Description:
The coronary artery system has 3 components with different functions: conductive epicardial
coronary arteries, arterioles, and capillaries. When any one of these systems fails,
myocardial ischemia can occur. Therefore, the presence of epicardial coronary artery stenosis
is not necessarily a prerequisite for ischemic heart disease (IHD). Although it has not been
established that microvascular disease is independent of macrovascular disease, clinical
studies have consistently shown that the presence of microvascular disease is an independent
predictor of poor clinical outcomes, especially in patients with acute myocardial infarction
(MI).
The pressure-derived fractional flow reserve (FFR) index has become a standard invasive
method to evaluate the functional significance of epicardial coronary artery stenosis, and
clinical outcomes of FFR-guided percutaneous coronary intervention (PCI) have proven to be
better than those of angiography-guided PCI or medical treatment. Although FFR-guided PCI has
been reported to improve patient outcomes and FFR is now regarded as the gold-standard
invasive method to assess the functional significance of coronary artery stenosis, there is
still room for further improvement in the diagnosis and treatment of patients with high FFR.
In the FAME II study, 14.6% of the registry arm (FFR > 0.80 and deferral of PCI) experienced
persistent angina, and 9.0% of these patients had clinical events during a 2-year follow-up
period.
Therefore, microvascular assessment using coronary flow reserve (CFR) and the index of
microcirculatory resistance (IMR) can provide additional diagnostic and prognostic insights
for IHD patients, especially in those with high FFR.
Recently, Lee et al. (JACC 2016) investigated clinical outcomes among patients with high-FFR
and deferred revascularization, according to physiologic classification using CFR and IMR.
Lee et al. firstly presented that 7.0% of patients with high FFR had high IMR and low CFR and
were regarded as having overt microvascular disease. Although the proportion of patients with
high FFR who had overt microvascular disease was small, Group D had the poorest clinical
outcomes during follow-up. The presence of overt microvascular disease was an independent
prognostic factor in patients with high FFR. In addition, the presence of overt microvascular
disease had additive prognostic value aside from clinical risk factors, with significantly
improved discriminant function of the prediction model. These results suggest that the
invasive physiologic assessment for microvascular disease combined with CFR and IMR can help
identify patients at high risk for future cardiovascular events among those with high FFR.
Previous studies have shown that the presence of microvascular disease is associated with a
higher risk of cardiovascular events such as cardiac death, MI, or revascularization in
patients without flow-limiting epicardial stenosis. Several mechanisms have been proposed for
the association of microvascular disease and poor clinical outcomes. In addition to
myocardial ischemia, microvascular disease is reported to be associated with endothelial
dysfunction and inflammatory activity that precedes intimal thickening, lipid deposition in
the macrovascular system, and coronary vasomotor dysfunction. In a study by Dhawan et al.,
coronary microvascular dysfunction in patients with non-obstructive coronary artery disease
was associated with higher serum high-sensitivity C-reactive protein and a higher frequency
of thin-cap fibroatheroma.
In the Lee et al.'s study, the higher clinical event rates in patients with overt
microvascular disease resulted from cardiac death and revascularization rates higher than
those of the other groups. These results imply that the presence of overt microvascular
disease can induce accentuated atherosclerotic progression and subsequent clinical events
including cardiac death and ischemia-driven repeat revascularization.
Therefore, the IMaging and Physiologic Predictors of Atherosclerotic Progression in Deferred
Lesions with Contemporary Medical Treatment based on Fractional Flow Reserve-guided Strategy
(IMPACT-FFR registry) was designed to compare the risk of atherosclerotic plaque progression
and subsequent clinical events between deferred lesions with or without over microvascular
disease, defined as physiological classification and also to explore independent predictors
of atherosclerotic lesion progression in deferred lesions based on fractional flow
reserve-guided strategy and treated by contemporary medical treatment.