Randomized study to assess the effect of thrombus aspiration on flow area in STEMI patients: an Optical Frequency Domain Imaging (OFDI) study

Primary percutaneous coronary intervention has been well established as the
treatment of choice for the majority of patients presenting with Acute ST
elevation myocardial infarction (STEMI). In fact primary PCI achieves better
Thrombolysis in Myocardial Infarction (TIMI) 3 coronary flow grade and results
in better ventricular preservation when compared to pharmacological
thrombolysis. However primary PCI alone is unable to remove intracoronary
thrombus and this often results in distal embolisation, no reflow which in turn
leads to impaired myocardial perfusion. This can result in left ventricular
dysfunction and subsequently increased mortality. Thrombus grade, a measure of
thrombus load in patients
presenting with acute STEMI correlates with mortality and adverse
cardiovascular events. The use of thrombectomy devices during PCI in the
setting of acute ST elevation myocardial infarction has been recently shown to
improve epicardial, myocardial perfusion, angiographical TIMI flow, blush
score, or result in less embolisation. Moreover thrombus aspiration or
rheolysis has been shown to decrease cardiac death and
repeat myocardial infarction.

On the other hand, the impact of thrombus on acute and chronic luminal
dimension is still unclear in a setting of primary PCI. After stenting, such
thrombus either:
I) protrude into the lumen through the mesh of metallic stent struts, or
II) is crushed between the vessel wall and stent.
Theoretically, the protruded thrombus can hinder the intra-luminal flow
immediately after stenting, while the resorption of crushed thrombus against
vessel wall might result at long term in stent malaposition. Due to the limited
ability of the conventional angiography and
the intravascular ultrasound (IVUS) to detect thrombus, these aspects have not
been investigated.

Optical coherence tomography has recently been shown to be feasible and to
provide valuable information in the setting of acute myocardial infarction.
This imaging modality has been shown to be even more sensitive to detect
intraluminal mass (i.e. thrombus) and offers unique possibilities of analysis
of coronary intervention in acute myocardial infarction.

To evaluate whether primary percutaneous coronary intervention (primary PCI)
with a new thrombectomy device as compared to primary PCI without thrombectomy
increases minimal flow area after stenting for treatment of patients presenting
with ST-segment elevation myocardial infarction (STEMI) as assessed by OFDI.

Prospective, randomized controlled, single blind, multicenter clinical study in
140 patients to show superiority of treatment with thrombectomy and Biolimus A9
drug-eluting stent [test] versus treatment with Biolimus A9 drug-eluting stent
only (without thrombectomy) [comparator].
Eligible patients (STEMI <12 hours from onset of chest pain) will be randomized
before the PCI in a 1:1 fashion to either primary PCI with thrombectomy or
without thrombectomy. All patients will receive the Nobori® drug eluting stent
and will undergo OFDI assessment of the culprit lesion immediately post-stent
implantation.
All Patients will be followed clinically at 30 days, 6 and 12 months
post-procedure.
Up to 40 patients in each arm (thrombectomy vs. non-thrombectomy) will undergo
a repeat OFDI evaluation of the infarct culprit coronary artery at 6 months.

OFDI Cathlab procedure
After stenting, patients will undergo the Optical Frequency Domain imaging.
The imaging region will be defined based on angiographic landmarks, such as
side branch take-offs, with a recommended length of 3-5 cm. The catheter and
OFDI imaging system will be prepared as outlined in the respective instructions
for use. All equipment to be used during the procedure will be carefully
examined to ensure proper performance. Computer controlled, constant velocity
pullback OFDI imaging will allow determination of the longitudinal position of
the imaging catheter. Landmarks including the distal end of the guiding
catheter and major side-branch vessels will be used to further improve
registration accuracy.

With any percutaneous procedure there are risks and complications. However, the
patients to be included in the study may be at greater risk as a result of
their disease state and general health status. The risks will be evaluated on
an individual basis and discussed with each Patient. This treatment may involve
some additional risks to the study patient, the natures of which are unknown.
Page 49 of the prococol includes an extensive list of anticipated adverse
events that may result from the PCI procedure and imaging devices.
The occurrence of these complications may lead to the need for a repeat
catheterization and/or PCI, myocardial infarction, emergency bypass surgery, or
death. Since the OFDI catheters are investigational devices, risks associated
with their use are not entirely known, but are believed to be similar to those
that are associated with currently used IVUS catheters to image coronary artery.

It should be noted, however, that there are no foreseen increased risks to
which subjects will be exposed by this study except extra catheters that will
be introduced with possible standard risk of vessel damage. However, the risks
described above will be minimized by selecting investigators qualified by
training and experience to investigate the device and patients which comply
with inclusion criteria. Each investigator will be trained in t he use of the
devices prior to use.