PET-CT and its RElationship in detection of Coronary plaques with Intravascular imaging methods: Optical coherence tomography (OCT) and intravascular UltraSound (IVUS)

Acute coronary syndrome (ACS) is often the first clinical presentation of
atherosclerosis. Angiographic and clinical findings are poor predictors of ACS.
This has led to the development of the concept of vulnerable plaque: a plaque
which is prone to rupture or highly thrombogenic, and therefore carries a high
risk of causing ACS. As a consequence, a considerable patient population with
subclinical coronary artery disease (CAD) is at risk of developing ACS in the
near future. The ultimate goal in the field of ACS is the detection of
vulnerable plaques even before ACS develops, which may create the possibility
to prevent ACS with medical or interventional treatment. To achieve this, it is
of immensely importance to develop a method to detect vulnerable plaques
non-invasively. One important characteristic of a vulnerable plaque is active
inflammation as a result of extensive macrophage accumulation. PET-CT has shown
to be an excellent imaging modality to detect even small amounts of
inflammation. In this study, we will investigate whether PET-CT findings
correlate with characteristics of vulnerable plaques found with the invasive
methods intravascular ultrasound (IVUS) and optical coherence tomography
(OCT).

The proposed project will have the following objectives:
1. To investigate the correlation between 18F-FDG accumulation in plaques seen
on PET-CT and plaque characteristics found with IVUS-VH and OCT.
2. To investigate the correlation between inflammation of the coronary arteries
and inflammation in other arteries (carotid, aortic and femoral arteries).
3. To evaluate the correlation between 18F-FDG accumulation in plaques and
serum biomarkers in all groups.

Patients are eligible for this study if they have a clinical indication for
percutaneous coronary intervention after they have been diagnosed with
non-ST-segment elevation myocardial infarction (NSTEMI) within the previous 5
days. Before any study-related procedure, written informed consent is obtained.
After coronary angiography, IVUS-VH and OCT measurements of the culprit lesion
is performed prior to PCI, except when ischemia is seen when IVUS-VH- or
OCT-catheters are passing the culprit lesion. If the PCI is successfully
performed, i.e. the remaining stenosis is less than 20 percent and no
dissection is made, patients undergo IVUS-VH and OCT, if suitable (at
discretion of the operator), in all three coronary arteries (including the
target vessel). As soon as possible, but at least within 72 hours after PCI,
patients will undergo 18F-FDG PET-CT. The findings of 18F-FDG PET-CT and
IVUS-VH/OCT will be analyzed and compared.

Patients are exposed to extra radiation burden due to injection of radio-active
glucose (18)F-FDG prior to PET scan, radiation due to low dose CT during
PET-CT, and the catheterization is elongated with 20minutes (although only a
couple of minutes extra fluorescence time). Because during the IVUS and OCT
assessment, extra catheters are placed in the coronary tree, there is a
slightly increas in the risk for dissection, or procedure related myocardial
infarction.

The burden associated with participation in this study consists of 2 times 20
minutes anamnesis, physical exam and EKG and elongation of the catheterization
with 20 minutes. The duration of the PET-CT (including preparation) will be
approximately 6 hours.