Laser Atherectomy for ST Elevation Myocardial Infarction

The objectives of this study are to observe and examine prospectively whether excimer laser coronary angioplasty (ELCA) and percutaneous coronary intervention with biodegradable-polymer platinum chromium everolimus-eluting stent may improve the myocardial salvage in the patients with anterior ST elevation myocardial infarction (STEMI) using the myocardial scintigram (acute-phase I123-BMIPP and chronic-phase 99mTc-tetrofosmin), and to clarify the myocardial protective effect of excimer laser in the patients with anterior STEMI.

The clinical result of catheter treatment in the patients with acute myocardial infarction in these several decades improved because of progress of early reperfusion therapy and stent treatment technique. However, the no-reflow phenomenon is still remaining as a problem, which is involved in a decrease in left ventricular function and worsening of prognosis. It is considered that the no-reflow phenomenon is induced by atherosclerotic and thrombotic emboli, endothelial dysfunction of capillary vessels, free radicals and cytokine. The treatment combining the peripheral protection and thrombus aspiration aiming at prevention of no-reflow is expected to reduce no-reflow and the infarct size and has been conducted on the patients with acute myocardial infarction. However, a lot of randomized studies have been conducted, so far, which do not lead to reduction of infarct size and improvement of survival rate, and the efficacy has not been demonstrated.

Some explanations have been suggested for this phenomenon:

1. The operation method of device is complicated, and it is difficult to acquire the treatment technique.
2. Giant thrombus and solid lesion could not be aspirated effectively.
3. A lot of randomized studies have not focused on the "patients with anterior descending lesion of thrombolysis in myocardial infarction (TIMI) grade 0/1, of which the time from onset to treatment is within 6 hours," considered to have the largest benefit of prevention of no-reflow.

In recent years in Japan, excimer laser coronary angioplasty (ELCA) has been used in the patients with acute coronary syndrome (ACS), and not only debulking of arteriosclerotic lesion but also thrombolytic effect have been reported. In the Camel trial and Utility of Laser for Transcatheter Atherectomy Multicenter Analysis around Naniwa (ULTRAMAN) registry, the efficacy and safety in ACS have been reported, but the infarct size has not been evaluated.

This time in this study, it is considered that verification whether or not ELCA is able to improve the myocardial salvage in anterior ST elevation myocardial infarction (STEMI) using myocardial scintigram (acute-phase BMIPP and chronic-phase TF) will provide the useful information helpful for selection of treatment to medical care staffs and patients for future patients suffering from ACS and will be able to contribute to further improvement of medical science and medical practice.

MRI will be performed twice at 5-9 days and at 6 months post index ST elevation myocardial infarction to assess myocardial damage and functional variables, which details will be described in the following outcome measurement section.

Eligibility Criteria:
Inclusion Criteria:

* Patients to whom PCI treatment for anterior STEMI is indicated \[Main selection criteria\]
* First-episode anterior STEMI patients within 6 hours of onset that satisfy electrocardiogram criteria
* Patients who are 21 years of age or older at the time of consent acquisition
* Patient who the patient himself agreed in writing

Exclusion Criteria:

* Patients presenting cardiac shock at the time of visit
* Patients whose target lesions are left main trunk, circumflex, right coronary artery, distal anterior descending branch
* Patients who have TIMI 2, 3 at the initial imaging
* Patients with a reference vessel diameter of 2.5 mm or less
* Patients determined to lack consent ability for mental or other reasons
* Patient who is judged inappropriate by research researcher or research sharing doctor

The inclusion and exclusion criteria for the MRI will follow the main study, but in addition, will exclude following conditions.

* Atrial fibrillation subject at the timing of MRI scan
* Internally implanted devices such as pacemakers or ICDs
* Subject that is allergic to Gadolinium,
* Subject with claustrophobia
* Pregnancy