To the Editor,
The Genous® stent (OrbusNeich, Fort Lauderdale, Florida, United States) is made of stainless steel coated with murine anti-CD34 monoclonal antibodies, an antigen present on the surface of endothelial progenitor cells. Because of this characteristic, circulating cells of this type are attracted to the stent and attach to the struts, resulting in prompt formation of a layer of functional endothelium in less than 2 weeks.1 In a highly prothrombotic clinical situation such as ST segment elevation acute myocardial infarction (STEAMI), fast endothelialization of the stent could hypothetically reduce the risk of thrombosis and the need for new target vessel revascularization (TVR)..
The aim of our study is to evaluate the safety and efficacy of the Genous® stent in patients with STEAMI undergoing primary angioplasty..
This is a prospective observational study carried out between June 2008 and July 2010, including 139 consecutive patients undergoing primary angioplasty with implantation of one or more Genous® stents. Patients who were hospitalized in cardiogenic shock, those in recovery from cardiac arrest, and patients with a formal contraindication for dual antiplatelet therapy for at least 1 month were excluded. The regimen for antithrombotic and anticoagulant therapy followed the recommendations of European guidelines for the management of acute myocardial infarction. Patients were followed up by telephone contact..
Cardiac death was defined as death due to a cardiac cause, an unknown cause, or a procedure-related cause. Clinical restenosis was established on the presence of anginal symptoms associated with >50% stenosis in the segment covered by the stent and the adjacent 5mm..
The patients’ baseline characteristics and the procedure-related characteristics are summarized in Table 1, Table 2..
Table 1. Baseline Characteristics of Patients With ST Segment Elevation Acute Myocardial Infarction Treated With a Genous® Stent.
| Age, years | 64±13.5 |
| Males | 104 (74.8) |
| Smokers | 67 (58.2) |
| Hypertension | 69 (49.6) |
| Hyperlipidemia | 66 (47.5) |
| Diabetes mellitus | 24 (17.3) |
| Previous AMI | 13 (9.4) |
| Chronic renal failure | 10 (7.3) |
| Previous revascularization surgery | 1 (0.7) |
| Previous PCA | 14 (10.1) |
| Maximum TpI, ng/mL | 93.1±87 |
| Multivessel disease | 28 (20.1) |
| Ejection fraction | 52.3±10.8 |
AMI, acute myocardial infarction; PCA, percutaneous coronary angioplasty; TpI, troponin I.
Data are expressed as mean±standard deviation or no. (%).
Table 2. Procedure-Related Characteristics.
| Radial access | 124 (89.2) |
| Culprit artery | |
| Anterior descending | 52 (37.4) |
| Right coronary | 66 (47.5) |
| Circumflex | 20 (14.4) |
| Baseline TIMI | |
| TIMI 0-1 | 115 (82.7) |
| TIMI 2-3 | 24 (17.3) |
| Total lesion length, mm | 22.6±8.7 |
| Number of stents per patient | |
| 1 | 106 (76.3) |
| 2 | 28 (20.1) |
| 3 | 5 (3.6) |
| Maximum lesion diameter, mm | 3.1±0.4 |
| Direct stent | 75 (54) |
| Thrombus aspiration | 80 (57.6) |
| Final TIMI | |
| TIMI 3 | 134 (96.5) |
| TIMI 1-2 | 4 (3.6) |
| No reflux | 9 (6.5) |
| Angiographic complications * | 18 (12.9) |
TIMI, thrombolysis in myocardial infarction.
Data are expressed as mean±standard deviation or no. (%).
* Distal embolization, lateral branch occlusion, dissection, or perforation.
All patients received dual antiplatelet therapy, which lasted for 1 year in 88 patients (65.2%). Mean follow-up was 538·(334.72) days. Five patients died during follow-up (3.6%): one death was due to noncardiac cause related to gastric neoplasm at 2 years following the procedure (cardiac mortality 2.9%, noncardiac mortality 0.7%), 2 patients died suddenly at home at 1 year and 2 years of follow-up, and 2 patients died during hospitalization (1 due to cardiac rupture and 1 due to cardiogenic shock and multiorgan failure)..
Based on the criteria of the Academic Research Consortium, there were 2 definite cases of thrombosis during follow-up (1.4%), one occurring during hospitalization and the other at 7 months following the procedure in a patient who had temporarily discontinued antiplatelet therapy..
Clinical restenosis occurred in 5% of cases, a new TVR was required in 5.8%, and target lesion revascularization (TLR) was needed in 3.8%..
Primary angioplasty is the treatment of choice in patients with STEAMI. Nonetheless, the choice of stent type remains controversial. Although it has been demonstrated that drug-eluting stents (DESs) effectively reduce restenosis, they can delay remodeling, a factor that has been related to thrombosis, particularly in high-risk situations, such as STEAMI.2 In a study by Planas et al.,3 8.6% of the patient group treated with DESs required TLR, a higher rate than was documented in our study. This difference may be related to the fact that the patients in that study underwent angiographic follow-up studies at 6 and 12 months, which could increase the indication for coronary interventions..
Few studies have been performed with the Genous® stent in primary angioplasty. In the registry carried out by Lee et al.,4 which contained 321 patients, definite thrombosis was reported in 0.9% and the total mortality rate was 5.8%. The most relevant finding of Lee's study was that there was no increase in the number of late thrombosis cases despite the use of dual antiplatelet therapy for 1 month. More recently, Low et al.5 reported a binary restenosis rate of 28% and lumen loss of 0.82 mm in a study including 95 patients with angiographic follow-up at 6 and 12 months. These values are higher than those obtained in our study and, again, can be related to a higher indication for coronary interventions in patients under angiographic follow-up..
In a comparison with other devices used in STEAMI cases, a study by Chong et al.6 showed that the Genous® stent was a comparable alternative to conventional stents and DESs; no significant differences were found in terms of TVR, non-fatal myocardial infarction, or long-term major cardiac events..
The Genous® stent seems to be a safe, effective option in STEAMI patients because of low associated rates of thrombosis and TLR. However, additional comparative studies with currently available devices are needed..
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Corresponding author: melisasantas@hotmail.com