Heparin-coated Stents Research Articles

Experimental study of a heparin-coated venous stent fabricated by atomic layer deposition.

To evaluate the safety and efficacy of heparin-coated venous stents in animals. We used atomic layer deposition technology to obtain a heparin coating with good stability and then prepared a heparin-coated venous stent based on this technology. The experimental stents were prepared according to the diameter of the rabbit inferior vena cava and were divided into Ni-Ti alloy stent group, Ni-Ti-Al2O3 stent group and Ni-Ti-Al2O3-Heparin stent group. 3 days, 7 days and 14 days after stent implantation, the materials were collected, and the three groups of stents were observed by hard tissue section pathology, immunohistochemistry and scanning electron microscope to observe the differences in vascular wall inflammation, thrombosis, lumen stenosis and vascular intima regeneration. The experiment confirmed the safety of the heparin-coated stent in vivo. Compared with the control group, the experimental group showed a high degree of vascular endothelialization and an intact neointimal structure 14 days after implantation. The long-term safety and biological effects of heparin-coated venous stents in animals require further study.

Iatrogenic Ureteral Injury Treatment with Biodegradable Antireflux Heparin-Coated Ureteral Stent-Animal Model Comparative Study.

Objective: The aim is to assess the effectiveness of a biodegradable antireflux ureteral stent with heparin coating in a comparative study (BraidStent®-H) in an animal model for the treatment of iatrogenic ureteral perforation. Materials and Methods: A total of 24 female pigs underwent initial endoscopic, nephrosonographic, and contrast fluoroscopy assessment of the urinary tract. Afterward, unilateral iatrogenic perforation in proximal ureter model was performed. Then the animals were randomly assigned to Group-I, in which a double-pigtail stent was placed for 6 weeks, or Group-II, in which a BraidStent-H a biodegradable heparin-coated stent was placed. Follow-up assessments were performed at 1 and 6 weeks and 5 months. Results: In terms of therapeutic effectiveness, complete resolution was observed in 95.8% of Group-I animals and 87.5% in Group-II. No animals in Group-II showed vesicoureteral reflux (VUR) during the study; statistical significance was observed at 1 and 6 weeks versus Group-I. All stents in Group-II degraded without producing obstructive fragments and allowed distal ureteral peristalsis. Heparin coating was not efficient to reduce asymptomatic bacteriuria between groups. Pathologic assessment did not show any significance in the global score, but did in the "fibrosis in muscular layer" parameter, at the ureteral perforation healing area; Group-II showed higher healing quality. Conclusions: The biodegradable intraureteral BraidStent®-H is highly effective for the minimally invasive treatment of ureteral perforation, since it displays controlled and predictable degradation, avoiding the development of VUR as well as irritation of the bladder trigone. Unfortunately, heparin coating was not effective in avoiding stent-associated bacteriuria.

Outcomes of the Japanese multicenter Viabahn trial of endovascular stent grafting for superficial femoral artery lesions

ObjectiveThe objective of this study was to assess 1-year safety, efficacy, and invasiveness outcomes of endovascular stent grafting of symptomatic long lesions (≥10 cm) in the superficial femoral artery (SFA) as a substitute for above-knee open bypass surgery. MethodsThis prospective, multicenter (15 hospitals) study assessed heparin-coated stent grafts for the treatment of long SFA lesions in Japanese subjects with peripheral arterial disease. Inclusion criteria were Rutherford category 2 to 5 symptoms (grade 5 without active infection), ankle-brachial index ≤0.9, and color flow duplex ultrasound-assessed SFA lesions with cumulative length ≥10 cm and ≥50% stenosis. Main efficacy and safety outcomes were primary assisted patency and adverse events, respectively. Secondary outcomes included primary patency using the surgical bypass definition, that is, blood flow through a device without requiring target lesion revascularization (TLR) to maintain or to restore flow. For comparison with prior endovascular studies, primary patency-interventional was defined as peak systolic velocity ratio <2.5 without TLR in treated lesions. Other outcomes included freedom from TLR and Vascular Quality of Life questionnaire scoring. General anesthesia avoidance and hospitalization duration were compared with historical data from 68 consecutive patients (n = 51 Rutherford 2/3 claudicants and 17 Rutherford 4/5 subjects) who underwent above-knee bypass surgery at study sites between 2002 and 2012 and met study enrollment criteria. ResultsOf 103 enrollees (74.2 ± 7.0 years old; 17.5% female; 97.1% claudicants), 100 subjects were evaluated through postoperative 12 months. Average lesion length was 21.8 ± 5.8 cm, and 65.7% were totally occluded. The whole-cohort Kaplan-Meier estimated primary assisted patency rate was 94.1% (95% confidence interval [CI], 87.3%-97.3%) at 12 months. The primary patency-surgical rate was 92.1% (95% CI, 84.8%-96.0%), the primary patency-interventional rate was 88.1% (95% CI, 80.0%-93.1%), and freedom from TLR was 93.1% (95% CI, 86.1%-96.7%). Mean ankle-brachial index increased from 0.64 ± 0.12 to 0.98 ± 0.12 at 1 month after intervention and 0.94 ± 0 .17 at 12 months (P < .0001 at both follow-ups). Target vessel revascularization, major amputation, or death did not occur through postoperative 30 days. No life- or limb-threatening intraoperative or perioperative adverse events and no acute limb ischemia cases were observed during follow-up. Vascular Quality of Life questionnaire score increased from 58.6% ± 15.7% to 72.9% ± 18.6% at 12 months (P < .0001). No stent fractures were detected. No stent graft participant required general anesthesia, and median postoperative hospital stay was 2.0 days (mean, 3.4 ± 2.9 days) in the Viabahn (W. L. Gore & Associates, Flagstaff, Ariz) claudicant subgroup, values that were significantly lower than the 76.5% general anesthesia rate (P < .0001) and 11.0 days median hospitalization stay (mean, 12.7 ± 5.3 days; P < .0001) in the 51 open bypass claudicant subjects. ConclusionsStent grafting appears to be a safe and less invasive alternative to above-knee bypass surgery, providing 88% to 92% primary patency at 12 months in long, complex lesions.

Effect of stromal cell derived factor-1α release from heparin-coated Co-Cr stent substrate on the recruitment of endothelial progenitor cells

The restoration of a damaged endothelium might be a fascinating way to reduce significantly late-thrombosis and restenosis in the stent treatment. It has been recently reported that the recruitment of endothelial progenitor cells (EPCs), capable for repairing a damaged endothelium, can be important in the vascular stent application. Therefore, we focused on the hypothesis that stromal cell-derived factor-1α (SDF-1α) acts as a key chemokine for the mobilization and recruitment of EPCs to the damaged endothelium lesion. In this study, the effect of SDF-1α released from a cobalt-chromium alloy (Co-Cr) plate, vascular stent material, was investigated on the recruitment of EPCs in vitro. Dopamine-conjugated heparin was synthesized to introduce heparin onto Co-Cr. Heparin-coated Co-Cr surfaces were examined by water contact angle and attenuated total reflectance-Fourier transform infrared (ATRFTIR) to prove successful coating of heparin. Finally, SDF-1α was bound to the coated heparin derivative. Amounts of loaded and released SDF-1α were measured by ELISA, and the recruited EPC by released SDF-1α was evaluated using two different migration assays. The quantity of SDF-1α bound to the heparin-modified surface increased in a concentration-dependent manner and SDF-1α was released over 28 days. Transwell migration assay revealed that soluble SDF-1α released from the heparin-coated Co-Cr induced significantly more EPC recruitment than bare Co-Cr and heparin-coated Co-Cr. More importantly, fibrin gel migration assay further demonstrated that EPCs evidently respond to heparin-based substrate with SDF-1α and this type of behaviors was surprisingly found at as low level as less 1 ng/day of SDF-1α. These results are strongly encouraging for further in vitro and in vivo studies. Open image in new window

A Bumpy and Winding but Right Path to Domestic Drug-Eluting Coronary Stents

Restenosis and stent thrombosis remain major concerns after percutaneous coronary intervention for the treatment of coronary artery disease. The present review was undertaken in order to highlight the various coronary stents that have been investigated in our Heart Research Center, and how far we have come from the first heparin-coated stent first used in the late 1990s. Thereafter, from the abciximab-coated stent to the current gene-delivery stent and other newer agents, our group has applied a range of techniques in this field. However, in groups similar to ours, the restenosis rates of such stents are still high for second-generation drug-eluting stents (DESs). Moreover, our nation imports almost all of these types of stents from other countries. Thus, we need to develop domestic coronary stents. Research into newer DESs are warranted in Korea so as to achieve improved safety and efficacy outcomes.

Does heparin coating reduce encrustation of biliary plastic endoprostheses? A prospective randomized trial

Objective. Common bile duct stenting is widely performed for bridging benign and malignant obstructions. A major limitation is early stent occlusion making regular stent exchange necessary. Covalent binding of glycosaminoglycanes to polyethylene stents proved to reduce encrustation in urological implants. Since development of urological and biliary stent occlusion shows parallels, the aim of the study was to evaluate the efficacy of heparin coating of biliary endoprostheses in preventing encrustation. Material and methods. In a prospective randomized trial, heparin-coated and native stents were endoscopically placed for almost 90 days on average. After removal, all stents were dried (50°C, 24 h), weighed and after longitudinal incision visible encrustation and discoloration recorded. Fifty-three patients (21 females/32 males, 70 ± 12 (42–87) years) were included; 13 patients (4 females/9 males, 58–79 years) completed the study according to the protocol. Results. After removal, mean weight of encrustation in native stents was more than double as high as of covered stents (native: 37.9 ± 19.8 (16–93) mg; covered: 17.6 ± 6.7 (9–33) mg). In 12 of 13 cases, the encrustation weight of the native stent was higher than that of the corresponding covered stent in the same patient. Premature stent explantation became necessary in 3 of 13 native stents, because of recurrent jaundice or cholangitis but only in 1 of 13 covered stents. After longitudinal incision, the three uncovered stents showed excessive encrustation whereas no significant encrustation was found in the covered prosthesis. Altogether, covered stents showed less visible accumulation of clogging material and discoloration than native stents. Conclusions. Covalent bound heparin is highly effective in preventing encrustation of biliary polyethylene endoprostheses.

Heparin-Coated Stents Do Not Protect Cancer Patients from Cardiac Complications after Noncardiac Surgery

Previous studies regarding preoperative coronary stents and antithrombotic agents have excluded patients with cancer as a result of hypercoagulability. The objective of this study is to determine whether preoperative heparin-coated coronary stents are as safe in patients with cancer undergoing surgery as patients without cancer. Between February 2003 and February 2005, 29 patients had heparin-coated coronary stents placed before noncardiac surgery. The incidence of postoperative myocardial infarction (MI) and/or death was compared in patients with and without cancer, and outcomes were further evaluated based on preoperative antithrombotic status. Postoperative MI occurred in three of 13 (23%) patients with cancer compared with zero of 16 noncancer patients. Patients with cancer were 9.6 times more likely to have a postoperative MI resulting in death compared with noncancer patients. There was a positive correlation between patients having cancer and having a postoperative MI (r = 0.38, P = 0.044) and between patients with cancer being on antithrombotic medications during surgery and having a postoperative MI (r = 0.567, P = 0.044). After stent placement, patients with cancer undergoing surgery experienced a higher incidence of postoperative MI resulting in death compared with noncancer patients despite continued antithrombotic use. In these patients, alternatives to stenting should be considered to avoid perioperative cardiac complications.

Abstract 5987: Long-Term Efficacy and Safety of Sirolimus-Eluting Versus Bare-Metal Stents for On- and Off-Label Indications

BACKGROUND: Although previous data suggest persistent clinical benefit of sirolimus-eluting stents (SES) in reducing target vessel revascularization without an increase in myocardial infarction (MI), cumulative stent thrombosis and mortality, the long-term safety and efficacy of CYPHER stent use in routine clinical practice, including off-label stent implantation, remains uncertain. METHODS: We examined clinical characteristics, angiographic findings, in hospital and long-term clinical outcomes in 3572 patients of whom 2,550 were treated with SES, and 1,022 who were treated with bare metal or heparin-coated stents (BMS). The study groups included 1,058 SES patients (41.5%) and 488 BMS patients (47.7%) with off-label indications, including acute MI, multivessel percutaneous coronary intervention, saphenous vein grafts and complex lesion morphology. A propensity-score method was utilized to adjust for differences in baseline characteristics. Patients were followed for up to 5 years for the occurrence of all-cause mortality, MI and repeat target vessel revascularization. RESULTS: Compared to the BMS patients, the SES group patients demonstrated significantly improved event-free survival with respect to all-cause mortality (RR, 1.39; 95% CI, 1.07 to 1.80, p=0.014) and repeat target vessel revascularization (RR, 2.72; 95% CI, 1.99 to 3.73, p&lt;0.001) during the follow-up period, with no significant difference in the incidence of MI. A landmark analysis, examining composite adverse events occurring six months after stent implantation in the two study groups, demonstrated no increased late hazard associated with SES use (relative risk, 1.08; 95% CI, 0.80 to 1.46). CONCLUSIONS : Use of SES in routine clinical practice, including off-label indications, is associated with improved long-term mortality, reduced need for repeat target vessel revascularization and no increase in MI compared to BMS.

Heparin Coating on Ureteral Double J Stents Prevents Encrustations: An in Vivo Case Study

To evaluate the ability of heparin coating to inhibit Double J stent encrustation and compare it with the classic polyurethane Double J stent. The study involved five patients with bilateral obstructions, who required bilateral ureteral Double J stent placement. Every patient received a heparin-coated Double J stent and a traditional polyurethane Double J stent for 1 month. After removal, the stents were analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and micro-infrared spectrophotometry (Micro-IR). These same techniques were used to analyze the heparin-coated and uncoated stents before insertion. The thickness, extension, and composition of encrustation of the coated and uncoated stents were compared. Moreover, two heparin-coated stents were analyzed with the same techniques after they had been in place for 10 and 12 months. FESEM analysis showed that the difference in encrustation thickness and extension between the two groups was significant. EDS and Micro-IR confirmed that in the heparinized stents the encrustations were not as uniform and compact as those in the uncoated stents. The stents that were left in place long-term were free of encrustations and had no changes in the heparin layer. Heparin coating reduces stent encrustation. Moreover, as no changes were seen in the heparin layer, we concluded that covalent heparin bonding enhances its adhesion to the polyurethane surface and ensures its stability for long periods. The heparin-coated stent appears to be a useful tool for long-term urinary drainage.

Use of Heparin-coated Stents in Neurovascular Interventional Procedures: Preliminary Experience with 10 Patients

Currently, there is minimal published data on the use of heparin-coated stents in the neurovasculature; however, these stents have a proven clinical record in the treatment of coronary disease. This article details our experience with the safety and technical aspects of stent deployment in the first 10 patients who had heparin-coated stents placed in the intracranial and cervical vasculature and the preliminary follow-up in most cases. We retrospectively reviewed the clinical history, intra- and periprocedural data, and imaging for the patients who received heparin-coated stents in the cervical and intracranial vasculature for cerebrovascular disease between October 2002 and October 2003. Thirteen heparin-coated stents were placed in 10 patients. Seven out of the 10 patients had heparin-coated stents placed in the posterior circulation; the remaining three patients had stents placed in the anterior circulation. Four patients had stents placed intracranially. There was no acute or subacute in-stent thrombosis and no procedure-related complications. Follow-up was performed on most patients, with no clinical symptoms attributable to restenosis in any patient. This small series suggests that heparin-coated stents are safe for use in the treatment of cervical and intracranial atherosclerotic disease. Longer-term follow-up is needed to study the heparin coating effect on in-stent restenosis rates and to assess the long-term durability and clinical efficacy of this stent. The use of drug-coated stents in the cerebrovascular circulation is an area that warrants further investigation.

Effects on blood compatibility in vitro by combining a direct P2Y12 receptor inhibitor and heparin coating of stents

The effect of the direct platelet P2Y12 receptor inhibitor, AR-C69931MX, on activation of blood induced by stents with and without heparin coating was investigated using a whole blood Chandler loop model in vitro. Stents were deployed in Chandler loops. Fresh human blood with heparin and AR-C69931MX was rotated for 1 h at 37°C and used for measurements of platelets, microparticles, thrombin-antithrombin complex (TAT), fibrinogen binding to platelets, P-selectin expression by platelets, CD11b, Prothrombin Fragment F1+2, FXIa-AT, FXIIa-AT, C3a, sC5b-9 and stent score. In the first experiment there were four study groups with unmodified stents: 1a, no AR-C69931MX; 1b, 250 nmol/L; 1c, 750 nmol/L; 1d, 2250 nmol/L of AR-C69931MX. In the second experiment the concentration of AR-C69931MX was 500 nmol/L: 2a; tubings without stent; 2b; tubings with heparin-coated stent; 2c; tubings with unmodified stents. Heparin-coated stents were used in the third experiment: 3a; no AR-C69931MX; 3b; 500 nmol/L of AR-C69931MX. In the first experiment there were significant differences in all parameters analysed except for C3a, and stent score when the group with no AR-C69931MX was compared to all the groups with AR-C69931MX. In the second experiment there were significant differences in platelet count, TAT, FXIa-AT, FXIIa-AT and stent score when unmodified stents were compared to loops with no stents and partly to loops with heparin-coated stents. In the third experiment there was a significant reduction in generation of TAT, stent score and better preservation of platelet number by combining the platelet inhibitor and heparin-coated stents as compared to heparin-coated stents alone. The conclusion is that the direct P2Y12 receptor inhibitor AR-C69931MX reduced the different aspects of activation of blood induced by both unmodified and heparin-coated stents.

An Internet-based registry examining the efficacy of heparin coating in patients undergoing coronary stent implantation

Heparin coating is an attractive alternative to counterbalance intrinsic stent thrombogenicity and to decrease the incidence of stent thrombosis. We compared, based on the data of an international multicenter prospective registry, the rates of stent thrombosis after percutaneous coronary interventions in native coronary arteries using a Bx VELOCITY heparin-coated stent versus a bare metal stent of the same design in a total of 3098 patients at high risk for stent thrombosis. Most patients in both groups underwent percutaneous coronary intervention for unstable angina (48.4% vs 47.5%, respectively) with > 25% of the patients treated for acute myocardial infarction (30.8% and 28.1%, respectively). Procedural success was high and very similar in patients with heparin-coated and bare metal stents (99.3% vs 98.8%, respectively, P = .11). The primary end point, a 30-day stent thrombosis, occurred in 0.6% of the 1417 patients treated with the heparin-coated stent and 0.9% of the 1681 patients treated with the bare metal stent (relative risk reduction 33%, P = .41). The rates of cardiac death, myocardial infarction, and target lesion revascularization did not differ significantly between the groups. By multivariate analysis, variables independently associated with 30-day stent thrombosis included the evidence of thrombus at baseline (odds ratio [OR] 3.0, 95% CI 1.29-7.0, P = .01), small vessel stenting (OR 2.41, 95% CI 1.01-5.74, P = .05), and target left anterior descending artery (OR 2.32, 95% CI 1.00-5.38, P = .05). This large-scale registry comparing the use of heparin-coated stent versus bare metal stent in the reality of daily practice showed no significant difference in stent thrombosis in patients with a high-risk profile for thrombotic complications.

Improved blood compatibility of a stent graft by combining heparin coating and abciximab

The aim of this study was to assess the combined effect of heparin coating of a stent graft and administration of abciximab, on platelet and coagulation activity in vitro. Methods: Stent grafts with an expanded polytetrafluoroethylene (ePTFE) membrane interfoliated between two stents were deployed in tubings to form Chandler loops. Fresh human blood with a low concentration of heparin and various doses of abciximab was rotated for 1 h, then collected and used for measurements of platelets, thrombin–antithrombin complex (TAT), CD11b, complement and contact activation of coagulation. In the first set of experiments, all stent grafts were heparin coated. There were three study groups: Group 1a (no abciximab, n=5); Group1b (abciximab in a concentration of 3.3 μg/ml, n=5); Group 1c (abciximab in a concentration of 8.3 μg/ml, n=5). In the second set of experiments, the concentration of abciximab was 3.3 μg/ml. There were three study groups: Group 2a (untreated stent grafts, n=4); Group 2b (heparin-coated stent grafts, n=4); Group 2c (heparin-coated PVC tubings with no stent grafts, n=4). Results: In the first set of experiments, there was a significant reduction in platelet count in Group 1c compared to Group 1a and Group 1b. There was a significant reduction in TAT in Group 1b and Group 1c as compared to Group 1a. In the second set of experiments, TAT was reduced in Group 2b and Group 2c compared to Group 2a. Contact activation was lowered in Group 1b and Group 1c as compared to Group 1a for both FXIa-AT (0.088 and 0.088 vs. 0.115) and FXIIa-AT (0.12 and 0.12 vs. 0.19). Conclusion: Heparin coating of a stent graft was shown to improve blood compatibility and this was further enhanced by addition of abciximab.

Comparison of outcomes up to six months of Heparin-Coated with noncoated stents after percutaneous coronary intervention for acute myocardial infarction

We prospectively followed 238 patients who underwent percutaneous coronary intervention for acute ST-elevation myocardial infarction and compared the outcomes of patients who received heparin-coated stents (n = 124) with those of patients who received noncoated stents (n = 114). The clinical characteristics and adjunctive medications of the 2 groups were similar. The use of heparin-coated stents was associated with improved 30-day outcome but had no significant effect on 180-day outcome.

The Long-Term Clinical Outcomes of Primary PTCA with Heparin-Coated Stent in Acute Myocardial Infarction

Background and Objectives:Primary percutaneous coronary intervention (PCI) has been reported to be effective reperfusion therapy for acute myocardial infarction (AMI). In the very thrombotic environment of AMI, primary PCI, with heparin-coated stents, has been known to reduce the early reocclusion of the stented vessel by preventing thrombosis. However, little data exist regarding the long-term clinical outcomes. The aim of our study was to evaluate the safety, feasibility and long-term efficacy of heparin-coated stents in AMI. Subjects and Methods:Between January 1998 and July 2002, primary PCI with heparin-coated stents was performed in 132 consecutive patients (98 males, with a mean age of 56.3±10.7 years) admitted with the diagnosis of AMI within 12 hours from the onset of the chest pain. Major adverse cardiac events (MACE), including death, MI, TLR (target lesion revascularization) and CABG, were recorded during hospitalization and the follow-up period. Angiograms were obtained at the baseline, after stent implantation and at 6 months following implantation. Results:The angiographic and procedure success rate was 96.2%. During hospitalization, there was no evidence of reocclusion of stented vessel, but 1 patient underwent a repeat PCI due to dissection. There were no bleeding complications. A six-month angiographic follow-up was completed in 47.2% of eligible patients and binary restenosis was present in 20.1%. During the long-term clinical followup (mean follow-up period 37.2±17.2 months), there were 12 deaths, 1 myocardial infarction and 18 TLR. The MACE free survival rate was 76.5%. Conclusion:Primary PCI, with heparin-coated stents, shows favorable long-term clinical outcomes. (Korean Circulation J 2004;34(6):540-547)

Safety of an aspirin-alone regimen after intracoronary stenting with a heparin-coated stent: final results of the HOPE (HEPACOAT and an antithrombotic regimen of aspirin alone) study

Safety of an aspirin-alone regimen after intracoronary stenting with a heparin-coated stent: final results of the HOPE (HEPACOAT and an antithrombotic regimen of aspirin alone) study

Heparin-coated stents: less early platelet activation

Heparin-coated stents: less early platelet activation

Platelet activation after stenting with heparin-coated versus noncoated stents

Background In animal models, heparin coating reduces platelet accumulation induced by coronary stenting. However, reduced platelet activation has never been demonstrated in humans. The purpose of the current study was to investigate the effect of heparin coating on platelet activation after coronary artery stenting. Methods In a prospective, randomized, pilot study of 50 consecutive elective patients, platelet activation was analyzed by measuring aggregation and surface receptor expression before and at 2 hours, 24 hours, 5 days and 30 days after implantation of either heparin-coated or noncoated stents . Results There was less platelet activation after implantation of a heparin-coated stent, as indicated by reduced expression at 24 hours of active glycoprotein (GP) IIb/IIIa (10.3 ± 6.1 vs 6.7 ± 2.1, P = .014), and total GP IIb/IIIa (382 ± 101 vs 306 ± 88, P = .01). A trend at 30 days poststenting of lower total (383 ± 150 vs 296 ± 86, P = .07) and active GP IIb/IIIa expression (10.3 ± 6.9 vs 7.5 ± 2.9, P = .15) was also observed with the heparin-coated stent). Aggregation and stimulated p-selectin did not differ between stent types. Conclusion Use of a heparin-coated stent in this pilot study of elective patients was associated with primarily less early platelet expression of GP IIb/IIIa. These findings have implications on the risk of subacute thrombosis and deserve further investigation.

Effectiveness of stents in small coronary arteries

This study was prospectively randomized to assess the efficacy and safety of Jo heparin-coated stent deployment in small vessels compared with balloon angioplasty. In 202 patients, restenosis in balloon and stent arms was 49% and 30%, respectively.

Drug-eluting stents: cost versus clinical benefit.

The publication in January 2001 of the first-in-man results showing zero restenosis after sirolimus-eluting stent implantation produced enormous excitement in the cardiological community.1 The long-awaited tool—a safe, restenosis-proof, easy-to-use stent—had been found. It was not too long thereafter that paclitaxel-eluting stents also demonstrated their capability to decrease restenosis. Today, both sirolimus- and paclitaxel-eluting stents have been shown in randomized trials to reduce restenosis as compared with conventional metallic stents (Figure 1).2–6 Most of these studies have been recently released in the form of abstracts during medical meetings and are still unpublished.3,5,6 In addition to sirolimus and paclitaxel, other agents have shown promising early results in recent studies, enlarging the body of evidence demonstrating the potential benefits of what are known as drug-eluting stents.7 Regulatory agencies have been very active in evaluating some of these devices in the United States, Europe, South America, and Asia. The sirolimus-eluting stent has been available for routine use in Europe, South America, and Asia since the first half of 2002 and received approval from the US Food and Drug Administration to be marketed in April 2003. Paclitaxel-eluting stents have also received CE (Conformite Europeenne) marking for commercialization in Europe and are now beginning to be commercialized. Figure 1. Randomized trials showing reduction of binary restenosis with drug-eluting stents.2–6 The case seemed to be closed. Restenosis, the Achilles’ heel of percutaneous revascularization, appeared defeated. However, since the sirolimus-eluting stents became available, very little has changed in the everyday life of almost all interventional laboratories in Europe. Why? Has the new treatment presented any undesirable effect? Was the desire to defeat restenosis not as great as supposed? The answer is none of the above. The limitation currently impeding more widespread use of the new technology is nontechnical, nonmedical, and nonbiological. The …