Efficacy of heparin-coated stent in early setting of acute myocardial infarction

Intracranial Stenting for Cerebrovascular Pathology

After reading this article, the participant should be able to:

Describe the use of stent-assisted angioplasty for intracranial atherosclerotic disease. Recall the present status of stent-assisted managment of intracranial aneurysms. Describe the role of stenting and its technical aspects in the treatment of arteriovenous fistulae and acute stroke.

Percutaneous Mechanical Reperfusion During Acute Myocardial Infarction

The treatment of acute myocardial infarction has progressed from bedrest to mechanical, catheter-based reperfusion. The authors review the use of percutaneous coronary intervention (PCI) as a primary treatment for acute myocardial infarction and the use of adjunctive agents. The most recent American College of Cardiology/ American Heart Association (ACC/AHA) guidelines for the use of PCI in ST segment elevation myocardial infarction (MI) advocate the use of PCI as primary therapy at those centers in which the procedure can be performed within accepted standards. Because a majority of hospitals (80%) do not have the capability of performing primary PCI, most patients are treated with thrombolytic therapy. PCI should be considered in those patients treated with thrombolytic therapy who have persistent or recurrent ischemia and/or cardiogenic shock. For patients with non-ST elevation MI, the use of an invasive strategy (early angiography and PCI if needed) has recently shown to be beneficial. Although revascularization is the basis of the acute therapy of MI, additional pharmacologic therapy in the acute setting is now recognized as a key to favorable long-term outcome.

Is there an alternative to systemic anticoagulation, as related to interventional biomedical devices?

To reduce the toxic effects, related clinical problems and complications such as bleeding disorders associated with systemic anticoagulation, it has been hypothesized that by coating the surfaces of medical devices, such as stents, bypass grafts, extracorporeal circuits, guide wires and catheters, there will be a significant reduction in the requirement for systemic anticoagulation or, ideally, it will no longer be necessary. However, current coating processes, even covalent ones, still result in leaching followed by reduced functionality. Alternative anticoagulants and related antiplatelet agents have been used for improvement in terms of reduced restenosis, intimal hyperphasia and device failure. This review focuses on existing heparinization processes, their application in clinical devices and the updated list of alternatives to heparinization in order to obtain a broad overview, it then highlights, in particular, the future possibilities of using heparin and related moieties to tissue engineer scaffolds.

The amount of fibrinogen-positive platelets predicts the occurrence of in-stent restenosis

AIMS

To determine the value of fibrinogen-positive platelet-analysis in predicting restenosis after stent implantation in acute myocardial infarction patients.

METHODS AND RESULTS

Our patient population comprised 50 patients who underwent intravascular ultrasound (IVUS) guided stent implantation for acute myocardial infarction. In all cases, IVUS confirmed a deep vessel wall injury due to a ruptured plaque within the culprit lesion. Flow cytometry quantified the amount of platelets with surface-bound fibrinogen and thrombospondin before and immediately after the intervention. After 5 months, IVUS was repeated to assess the long-term results. In-stent restenosis - defined as a percent diameter stenosis of >50% - was detected in 11 of 45 patients who attended follow-up angiography. The amount of fibrinogen-positive platelets was significantly higher among patients who subsequently developed in-stent restenosis (50.5+/-6.8% fibrinogen-positive platelets immediately after intervention) than among those who did not (39.7+/-12.3% fibrinogen-positive platelets, p<0.005). Receiver operating characteristic curve revealed a 40% cut-off for fibrinogen-positive platelets immediately after the intervention to predict restenosis (p<0.05, sensitivity: 90.9%, specificity: 47.1%).

CONCLUSION

The amount of fibrinogen-positive platelets immediately after stent implantation predicts the occurrence of in-stent restenosis, as confirmed by IVUS in acute myocardial infarction patients.

The favorable clinical and angiographic outcomes of a high-dose dexamethasone-eluting stent: randomized controlled prospective study

BACKGROUND

Previous studies with dexamethasone-eluting stents could not elucidate the role of dexamethasone in the prevention of neointimal hyperplasia because they did not compare their results with a control group. We prospectively evaluated the clinical and angiographic outcomes of dexamethasone-eluting stents, comparing them with unloaded stents of an identical design.

METHODS

A total of 92 patients (98 lesions) were randomly assigned to the dexamethasone group (67 patients, 71 lesions) or control group (25 patients, 27 lesions). The inclusion criteria for a stent implantation were a de novo lesion with a diameter of 2.60 to 4.0 mm. BiodivYsio Drug Delivery phosphorylcholine-coated stents (Biocompatibles Ltd, Galway, Ireland) were immersed in a 20-mg/mL dexamethasone solution, yielding a total dexamethasone dose of 0.5 microg/mm2 per stent.

RESULTS

The total major adverse cardiac events rate at 12 months was significantly lower in the dexamethasone group, as compared with the control group (10.4% [7/67] vs 28.0% [7/25], P = .037). The binary restenosis rate at 6 months was 11.9% (7/59) in the dexamethasone group and 42.9% (9/21) in the control group (P = .002). The use of dexamethasone-eluting stents was the only independent predictor for the major adverse cardiac event at 12 months (relative risk 0.20, 95% CI 0.06-0.68, P = .009) and binary restenosis at 6 months (relative risk 0.17, 95% CI 0.05-0.60, P = .006) by multivariate analysis.

CONCLUSIONS

Dexamethasone-eluting stents exhibited an improvement in the clinical and angiographic outcomes, as compared with the control stents. These results suggest that dexamethasone may play an important role in the inhibition of the polymer-induced inflammation in the era of drug-eluting stents.

Use of heparin-coated stents in neurovascular interventional procedures: preliminary experience with 10 patients

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

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

BACKGROUND

Heparin coating is an attractive alternative to counterbalance intrinsic stent thrombogenicity and to decrease the incidence of stent thrombosis.

METHODS

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).

RESULTS

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).

CONCLUSION

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.

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.

Subacute stent thrombosis associated with a heparin-coated stent and heparin-induced thrombocytopenia

Subacute stent thrombosis occurred in a patient 34 days after receiving a heparin-coated (HC) stent. The patient developed heparin-induced thrombocytopenia and diffuse thrombosis after the stent was placed. This raises the concern that patients who develop heparin-associated antibodies in the context of a recently placed HC stent may have an increased risk for subacute stent thrombosis.