Randomized Study to Assess the Effect of ThRombus Aspiration on Flow Area in STEMI Patients

Randomized Study to Assess the Effect of ThRombus Aspiration on Flow Area in STEMI Patients: an Optical Frequency Domain Imaging (OFDI) Study

The purpose of the study it 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.

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). 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.

The use of thrombectomy devices during percutaneous coronary intervention 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.

It is estimated that late stent malapposition is more common after stenting in the course of primary PCI as compared with elective PCI, and may predispose to stent thrombosis. Late malapposition may be related to underdeployment of stents at the time of primary PCI, and this may be due in part to thrombus behind the stent, which subsequently resolves and leads to stent malapposition. Removal of thrombus before stenting potentially could lead to better stent expansion and less late malapposition.

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.

TERUMO OFDI is a novel optical imaging device that uses a scanning laser as light source which centre wavelength is around 1.3 μm with sweeping range over 100 nm. The echo-time delay and the amplitude of light reflected from the tissue microstructure at different depths are determined by processing the interference between the tissue sample and a fixed reference mirror.

Compared to the conventional OCT imaging devices, OFDI has a higher temporal frame rate (160 frames/sec), with a faster pullback speed of maximally up to 40 mm/s. The safety and performance of the device has been investigated in the First-in-man study enrolling 19 patients where both IVUS and OFDI were performed. In the study, OFDI was associated with no device-related adverse events, and with a good correlation with IVUS measurement.

We hypothesize that TERUMO Eliminate® thrombectomy device will reduce the thrombus burden in STEMI patients and this will result in less intraluminal material and larger flow area, measured with OFDI. This will be clinically translated in a better restoration of blood flow and reduce further damage of the myocardium.

In addition, a reduction of thrombus burden would eventually result in less stent malaposition at 6 months. Given the benefits of reducing thrombus burden in STEMI as described above, the study may have important implications on the prove of the effectiveness of the thrombectomy device and the use of this imaging modality to assess its efficacy. To best assess benefits of thrombus removal, a randomized controlled study was considered the most appropriate method.

Inclusion Criteria:

• Patient is at least 18 years of age.
• Patients with a ST-elevation Myocardial Infarction documented in an ambulance or in a Cathlab with ≥2 mm ST segment elevation in at least two contiguous leads, presenting in the Cathlab <12 hours after the onset of symptoms lasting ≥20 min and having an angiographical visible stenosis (>30%) or TIMI≤ II in de-novo, native, previously unstented vessel.
• The single vessel coronary artery disease.
• Signed Informed Consent.
• The patient understands and accepts clinical follow-up and OFDI controls.
• Patients residence is in the area covered by hospital. Angiographic
• Vessel size should match available Nobori stent sizes (<4.0 mm, and >2.0 mm by visual assessment).

Additional Inclusion criteria (applicable only for France)

• Patients residence is in the area covered by hospital.
• Patient is affiliated to social security or equivalent system.

Exclusion Criteria:

• Pregnancy and women of child bearing potential (less than 50 years of age).
• Known intolerance to aspirin, clopidogrel, heparin, stainless steel, Biolimus A9, contrast material.
• Diameter Stenosis <30% in the target lesion.
• The multi-vessel coronary artery disease (DS>50%).
• Unprotected left main disease with a diameter stenosis of >30% by visual assessment.
• Distal vessel occlusion.
• Severe tortuous, calcified or angulated coronary anatomy of the study vessel that in the opinion of the investigator would result in sub-optimal imaging or excessive risk of complication from placement of an OFDI catheter.
• Fibrinolysis prior to PCI.
• Known thrombocytopaenia (PLT< 100,000/mm3).
• Contraindication to PCI, stenting, ASA, clopidogrel.
• Active bleeding or coagulopathy or patients at chronic anticoagulation therapy.
• Cardiogenic Shock.
• Significant comorbidities precluding clinical follow-up (as judged by investigators).
• Major planned surgery that requires discontinuation of dual antiplatelet therapy.
• Proximal RCA stenosis (>30%) if the infarct-related artery is mid-RCA or distal-RCA.
• People under judicial protection.
• A patient who has congenital heart disease, severe cardiac valve disorder and/or myocardial disease (excluding status post MI).
• Patient participating in other clinical research study.