DYNAMIC STRESS PERFUSION CT FOR DETECTION OF INDUCIBLE MYOCARDIAL ISCHEMIA

Cardiac computed tomography (CT) provides accurate assessment of the coronary
arteries and detects significant coronary stenosis with high diagnostic
accuracy. However, the hemodynamic relevance of these stenotic lesion remains
unclear, although highly relevant for clinical decision-making. Recent
technical developments with third-generation dual-source CT allow to determine
myocardial perfusion during hyperemia and thus for assessment of the
hemodynamic relevance of coronary lesions using a dynamic acquisition mode. To
date, there is only very limited evidence of the feasibility of this approach
stemming from single-center studies with varying standards of reference.

To determine the diagnostic accuracy of MPICT for the detection of
hemodynamically relevant coronary stenosis (as determined by invasive FFR) in
patients with suspected or known CAD clinically referred for invasive
angiography. In an optional sub-study the diagnostic accuracy of MPICT for the
detection of myocardial perfusion defects as determined by cardiac magnetic
resonance imaging (CMRI) will be investigated.

Observational cohort study with fractional flow reserve (FFR) during invasive
angiography as the reference standard.

The study protocol comprises the CT examination including a standard cardiac CT
angiography with the injection of iodinated contrast and a CT perfusion
acquisition under pharmacological stress using the latest 3rd generation
dual-source CT system. Patients will undergo cardiac catheterization as part of
their clinical care (inclusion criterion). FFR will be performed in all
potentially hemodynamically relevant lesions (25% to 90% luminal narrowing),
which may include lesions otherwise not investigated based on available
noninvasive test results. Optionally, subjects may also undergo CMR if
available locally and selected by participant forming an MR sub-study. All
study exams will be performed in this population according to international
guidelines.
The dynamic CT perfusion exam is safe, has been previously applied, and uses a
validated pharmacological stress agent (adenosine). Standard risk of CT
scanning include radiation exposure (10mSv or less), contrast related allergies
or contrast nephropathy. All measures will be taken to keep the radiation dose
low, while patients at risk for contrast related injury will be excluded. The
optional MRI is free of radiation, although contrast allergies may occur and
patients with kidney dysfunction will be excluded in order to avoid the risk of
nephrogenic systemic fibrosis. Some FFR measurements will be performed for
research purposes only, which in rare cases is complicated by damage to the
coronary artery. However, these FFR measurements have been shown to improve
patient care (DEFER, FAME, FAME2). All examinations are performed by
experiences personnel, qualified and able to handle any adverse events
occurring.
Although there are no direct rewards, patients may benefit from the additional
information from imaging not related to the study (infarct detection and
ventricular function on MRI), incidental imaging findings (i.e. bronchial
carcinoma), and the clinically validated information from the additional FFR
investigations, which could favorably alter clinical decision making. If
confirmed, future patient populations may substantially benefit from a combined
CT procedure that includes morphologic and functional information (dynamic CT
perfusion) in a single and comfortable exam.