Not DES, Not BMS: The Catania Stent

How is the Catania Stent unique? The Catania Stent (CeloNova BioSciences, Newnan, GA), a cobalt chromium stent with a modified, open-cell design, is surface-modified by the NanoThin Polyzene®-F polymer, which is the main characteristic of the stent. Preclinical studies demonstrate that Polyzene-F has very positive effects once it is introduced in the human body. Particularly important from the interventionalists’ point of view is that Polyzene-F has very low surface thrombogenicity. In addition, this polymer has anti-inflammatory and bacterial resistance qualities, as well as a pro-healing effect. The final result is a very low rate of stent thrombosis. This stent also has a high rate of endothelialization compared to bare-metal and drug-eluting stents, as demonstrated by optical coherence tomography (OCT) studies. The Catania stent is not a drug-eluting stent and not a bare-metal stent, but somewhere in between. What were the results of the first-in-man ATLANTA Trial? The ATLANTA trial was designed in order to assess the safety and efficacy of the Catania stent. We selected 55 patients with fairly complex lesions and in these patients, at the time of the index procedure, we performed invasive angiography and percutaneous coronary intervention (PCI), and in a subgroup of 15 patients, we also performed intravascular ultrasound (IVUS) and OCT. All patients at follow up underwent IVUS. The same 15 patients who received OCT at the time of the PCI underwent OCT also at follow up to assess the degree of the endothelialization and to detect any non-positive reaction of the vessel to the Polyzene-F. Fortunately, we did not see any adverse reaction to the polymer. Patients had at least one and up to two type A or B-1 lesions according to American Heart Association/ American College of Cardiology classifications. Lesion length was less than 20 mm, and vessel size between 2.5 and 3.5 mm. Patients were selected by visual estimation. The maximum stent length allowed was 24 mm. At the independent core lab analysis, we found that 15 lesions we had estimated as type B lesions were adjudicated as type C lesions. One of the criteria to define type C lesions is length, so some lesions that were estimated by us at 19 mm, were judged to be 21 mm, and passed from type B to type C lesions. You can see that the study population was fairly complex, because type C lesions are the worst type of lesions that we can treat. Results at 6 months were consistent with a very good performance of the stent. Quantitative coronary analysis has shown that the reference vessel diameter at 6 months was only 2.55 mm. That means we are faced with a high percentage of small vessels in the study population, which have a high rate of restenosis. Yet despite the high percentage of small vessels as well as the high percentage of diabetic patients (34%) in the trial, clinically-driven revascularization was only 3.6%, while all revascularization was 9.1%, with zero myocardial infarction and zero stent thrombosis. Antiplatelet therapy was given for one month. According to the absence of drugs on the stent, we gave aspirin, ticlopidine and clopidogrel for 4 weeks and then the patient remained only on the aspirin. Two patients were suspended just after the PCI. One stopped all drugs and another was suspended due to intolerance to clopidogrel two weeks after stent implantation. Neither of these patients had any thrombosis. This is similar to other patients in our personal registry who also had contraindication to anti-platelet therapy. We implanted the Catania stent in these patients, followed the stent by IVUS, OCT and angiography, and found zero thrombosis. Can you share more about your patient registry? In my hospital, we feel comfortable enough with this stent that in patients requiring a bare-metal stent, we now use the Catania stent instead. Currently, the registry has more than 250 patients who have received the Catania stent. In this population, there are 39 patients with acute myocardial infarction (AMI), since in AMI, we prefer to implant a non-drug-eluting stent. So in these cases, the Catania stent was implanted as the first-choice stent in patients with AMI. Results of our registry thus far confirm the first-in-man ATLANTA trial. The registry has a median 10 months follow up showing 7.8% major adverse cardiac events (MACE), with zero cardiac death and zero myocardial infarction. Target lesion revascularization (TLR) in diabetics and in non-diabetics is 10.8 and 6.6%, respectively, with an average TLR of 7.8% among the whole population. Since it is not useful to give the TLR for patients who received the stent 1 month ago, these numbers are from 130 patients with more than 6 months follow up. Additional data was recently presented at ISET and JIM. In the 18-month data for the ATLANTA trial, only one additional clinically-driven TLR was added to the first-in-man study. OCT performance in 3 patients at 18 months showed no adverse reaction of the body against the stent and the Polyzene-F, a confirmation of the safety and efficacy profile of the stent. The Catania is now CE marked. How much of your practice has moved to the Catania? As I noted, patients who used to receive a bare-metal stent now receive a Catania stent. That’s perhaps 20-25% of our patient population, depending on the week. In my cath lab, 90% of non-eluting stents are the Catania stent. You mentioned that you are also using this stent in acute myocardial infarction patients. We published a retrospective analysis of our experience, looking at all patients receiving a bare-metal stent or a drug-eluting stent in our hospital. We observed that the rate of AMI, stent thrombosis and death was significantly higher after drug-eluting stents in comparison with non-drug-eluting stents, so at that time, we decided to implant bare-metal stents in all patients with AMI, unless there is very complex anatomy specifically requiring a drug-eluting stent. Now that we have shifted from bare-metal stents to the Catania stent, we don’t use any more drug-eluting stents in AMI. What problems with today’s stent options do you think the Catania Stent technology solves? In our real-world registry experience with almost 300 patients, we observed, in comparison to other stents, clear superiority in events such as stent thrombosis. In a retrospective study using some adjustment in order to better understand how the stent behaves, we compared bare-metal and drug-eluting stents over past years with the Catania population. We matched the population for similar characteristics and observed that the rate of stent thrombosis is lower. In fact, the only stent thrombosis which occurred was due to stent underexpansion, i.e. a mechanical problem, not a problem with the Catania stent. In this case, there was another Catania stent proximal to the occluded stent which was viable even one day after the thrombosis. That means that the stent is not thrombogenic, because in cases we observed with other stents, the entire vessel is occluded. It is our view that the Catania stent will overcome the problems related to stent thrombosis, as well as eliminate the economic burden of dual anti-platelet therapy and the additional costs for patients who prove intolerant to this therapy. The Catania stent seems to have some characteristics pertaining to a bare metal stent, others pertaining to some drug-eluting stents, and some which are strictly individual, linked to the Polyzene-F polymer. Late loss, for example, is exactly the same as was observed with the first generation of the Medtronic Endeavor, a drug-eluting stent. I would say that the Catania takes the best from each category of stent. What are plans for future work with the stent? There are some other registries that are ongoing. There is a Sicilian registry, where six centers are planning to participate. Two of those six centers have already started to enroll patients. By the end of the year, we plan to enroll 400 patients in our registry that will be followed for two years in order to give a real-world assessment of the stent. Is there anything else you’d like to mention? We have seen a trend of diabetic patients receiving the Catania stent having similar outcomes to non-diabetic patients. It is absolutely unexpected and has yet to be confirmed. Usually, diabetic patients have double the restenosis and late loss of non-diabetic patients. With the Catania stent, we have seen a trend of both groups having equal rates of restenosis and late loss, also confirmed by initial OCT evaluation. Also, we are currently completing the Rapid Evaluation of Vessel HEaling After AngiopLasty (REVEAL) Trial, a study where the same patient receives two types of stents. At one week and one month, respectively, in different arms, we check the degree of strut coverage by OCT. This study is unique in that we don’t have the bias of different stents in different patients — we have different stents in the same patient. Thus far, in our particular results, at one month there is significantly more coverage with Catania stent in comparison to bare-metal stents and much more coverage than with drug-eluting stents. It justifies the early suspension of dual anti-platelet therapy in Catania stent patients. As an example, I have a physician patient who is 80 years old, had unstable angina and was unable to receive surgery. I implanted three stents in the left anterior descending artery (LAD) and in a chronic total occlusion in the right coronary artery. This patient received Catania stents and went without any anti-platelet therapy. I followed the patient, with a new angio and OCT at one week, because I was afraid of the risk of thrombosis. Angio and OCT demonstrated that there wasn’t any thrombus whatsoever in the coronary arteries. I am following this patient personally, and at almost one year follow up, he is doing very, very well. There are some other similar cases that we are following, all of whom have demonstrated a lack of stimulus for thrombus formation with the Catania stent. Dr. Tamburino can be contacted at tambucor@unict.it

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