X-Sizer registry

Dr Garcia reviewed the Xamine-ST study, which was designed to evaluate the efficacy of the X-Sizer thrombectomy catheter system in the treatment of patients with acute myocardial infarction.

Xamine-ST was a randomized study that was undertaken in Europe at 14 centers involving 201 patients. Out of the 200 patients, 101 were treated with conventional therapy (ballooning and stenting) whereas in the other 100 mechanical removal of thrombus was done with the X-Sizer, prior to stent implementation.

Dr Garcia said, "The inclusion criteria were mainly patients with ST-elevation myocardial infarction who had obvious thrombus in the coronary artery, which means that the TIMI flow in the initial angiography was 0 or 1. The results showed that the X-Sizer was more efficient in producing better ST resolution in the electrocardiogram, which was the primary endpoint of the study, and a surrogate for myocardial perfusion. Secondly, it was also more efficient in reducing the incidence of distal embolization, slow flow or no-reflow phenomenon. Essentially, the device was able to restore better epicardial and myocardial flow."

He continued, "We now use X-Sizer in 45-50% of our acute myocardial infarction patients. The indication is ST-elevation acute myocardial infarction in which we believe that thrombus is the main component of the occlusion. That is mainly patients with proximal occlusions of the coronary artery vessels, young patients, and patients without previous history of coronary artery disease that suddenly develop an acute myocardial infarction. We usually don't use the device in old patients in whom we believe that there was previous long-standing coronary artery disease, where the main component of the obstruction is previous plaque."

According to Dr Garcia, a multi-site registry has begun in Spain and Portugal and centers from other European countries are also expected to join. "It is mainly an observational study to see what the use of X-Sizer is in the setting of acute myocardial infarction and also to assess the outcomes," said Garcia. Again, as in the study, the primary endpoint will be ST-resolution.

"We now have 20 centers from Spain and eight from Portugal involved in the registry, and we are waiting for centers from France, Austria and probably England and some other countries," Garcia told Cardiovascular News. "X-Sizer has proven to be effective in a randomized study. However, there remains the issue of proving superiority compared to conventional therapy in terms of clinical events, because the clinical results in primary angioplasty are good even with the traditional therapy of balloon and stent. We feel that in some patients, especially in those with a large thrombus burden in the setting of acute myocardial infarction, X-Sizer is effective. We will try to prove in this more extensive observational study that it is safe and easy to use."

Commenting on other devices that are available, Garcia said: "The rheolytic thrombectomy devices such as the Angiojet have no proven any benefit in randomized studies." He continued: "Then there are thrombectomy aspiration catheters that seem to be effective in terms of removing thrombus, but there are no clinical studies that support their efficacy in comparison to conventional therapy, looking at the myocardial perfusion. At the end of the day it is not the question of if the device is able to remove thrombus; it is about improving the myocardial perfusion. You may remove some thrombus, but at the same time you may produce embolization of the remaining thrombus, which is not very good for the patient. I think aspiration catheters, in my opinion, need to prove clinical benefit in comparison with traditional therapy and other devices."

Garcia concluded by saying that he believes that X-Sizer could become a standard treatment for about half of the patients in the setting of acute myocardial infarction, but to achieve this the company, ev3, needs to improve the device "a little" by making it "rapid exchange and maybe more flexible, thereby making the procedure even simpler".