Three-year follow-up after implantation of metallic coronary-artery stents

Two-year follow-up intravascular ultrasound analysis after bare metal stent implantation in 120 lesions

The objective of this study was to examine long-term changes after bare metal stent implantation in a relatively large number of patients. There are few reports of intravascular ultrasound (IVUS) studies performed on stented and nonstented (reference) segments beyond 6 months after bare metal stenting. Using IVUS, we evaluated serial changes in stented and reference segments between 6 and 24 months after stent implantation in 110 patients with 120 lesions. Serial IVUS images were acquired at five equidistant intrastent sites and at two different reference segment sites. Measurements were made of the external elastic membrane (EEM), stent, lumen, and intimal hyperplasia (IH = stent - lumen) area. For the whole patient group, between 6 and 24 months, the mean IH area in stented segments decreased from 2.6 +/- 1.0 to 2.3 36+/- 0.9 mm2 (P < 0.001), and the mean lumen area increased from 6.2 +/- 2.0 to 6.5 +/- 1.9 mm2 (P < 0.001). The mean IH area decreased in 91 lesions (76%) and increased in 29 lesions (24%) between 6 and 24 months. There were no significant changes in EEM or lumen area in the reference segments. Late angiographic restenosis (diameter stenosis > or = 50%) occurred in three lesions between 6 and 24 months. A late target lesion revascularization was performed for one lesion. In the period of time between 6 and 24 months after stenting, IH regression occurred in most (76%) stent lesions, resulting in late lumen increase. However, IH progression was observed in 24% of in-stent lesions. No significant changes of EEM or lumen area occurred in the reference segments.

Relationship between angiographic late loss and target lesion revascularization after coronary stent implantation

OBJECTIVES

We sought to evaluate the relationship between angiographic late loss and clinical outcomes in the drug-eluting stent era.

BACKGROUND

The interrelationship between angiographic late loss, binary restenosis, and clinical recurrence (target lesion revascularization [TLR]) after coronary stent implantation has been incompletely evaluated.

METHODS

Using the angiographic substudy of the TAXUS-IV trial, in which 1,314 patients with de novo coronary lesions were randomized to either the paclitaxel-eluting TAXUS stent or to its bare-metal equivalent, we defined the relationship between in-stent and analysis segment late loss, the shape of the late loss histogram (variance and skewedness), and nine-month TLR.

RESULTS

Late loss by several measures was closely related to TLR (area under the receiver-operator curve >0.90). For individual vessels of the size in this study (2.8 +/- 0.5 mm), the likelihood of TLR did not exceed 5% until analysis segment late loss was >0.5 mm, and did not exceed 10% until late loss was >0.65 mm. At greater late losses, the late loss TLR relationship was steep and nearly linear. For the overall patient cohort, the rate of TLR was related, however, not only to median late loss, but also to measures of its statistical distribution (TLR increased with lack of homogeneous biologic response [greater variance and greater right skewedness]). Similar relationships held for late loss measured within the confines of the stent itself.

CONCLUSIONS

Coronary stents result in large lumens with "room" to accommodate up to approximately 0.5 to 0.65 mm of tissue (angiographic analysis segment late loss) before the likelihood of clinical restenosis (TLR) exceeds 5% to 10%. These data have important implications toward understanding the absolute and relative efficacy of drug-eluting stents.

Revascularization of the Right Coronary Artery: Grafting or Percutaneous Coronary Intervention?

BACKGROUND

The choice of myocardial revascularization strategy for the right coronary artery (RCA) in patients with multivessel disease and chronic stable angina remains controversial. Our aim was to determine the better strategy-hybrid, combining bypass of the left coronary network and percutaneous coronary intervention of the RCA, or exclusively surgical-and if the latter, the best conduit.

METHODS

We used decision analysis, a modeling technique, to compare two RCA revascularization strategies: surgical grafting and percutaneous coronary intervention. A review of the English language literature determined the variables for each strategy. All possible outcomes of each strategy were analyzed to determine the baseline strategy yielding the highest expected effectiveness. Sensitivity analysis determined the most relevant elements in the model and indicated threshold values.

RESULTS

Arterial grafting of the RCA led to the highest expected effectiveness, respectively 6% and 7% higher than that of percutaneous coronary intervention and the saphenous graft procedure. Of the arteries available-the radial, right gastroepiploic, and right internal thoracic artery-the most effective was the right internal thoracic artery, pedicled for the proximal part of the RCA and free connected as a Y or a T to the pedicled left internal thoracic artery for the distal part of the RCA. Sensitivity analysis showed surgery to be the appropriate strategy when the expected 1-year patency rate of the arterial graft exceeded 80%.

CONCLUSIONS

This analysis shows arterial grafting of the RCA to have better outcomes than percutaneous coronary intervention, and the right internal thoracic artery to be the best conduit.

Stent thrombosis following bare-metal stent implantation: success of emergency percutaneous coronary intervention and predictors of adverse outcome

AIMS

To investigate the efficacy and outcome of emergency percutaneous coronary interventions (PCI) in patients with stent thrombosis.

METHODS AND RESULTS

Between 1995 and 2003, 6058 patients underwent bare-metal stent implantation, of which 95 (1.6%) patients suffered from stent thrombosis. The timing of stent thrombosis was acute in 10 (11%), subacute in 61 (64%), and late in 24 (25%) patients. Procedural and clinical outcomes of emergency PCI for treatment of stent thrombosis were investigated. Emergency PCI was successful in 86 (91%), complicated by death in 2 (2%), and coronary artery bypass grafting in 2 (2%) patients. Myocardial infarction occurred in 77 (81%) patients with a peak creatine kinase level of 1466+/-1570 U/L. Left ventricular ejection fraction declined from 0.54+/-0.19 prior to 0.48+/-0.16 (P<0.05) at the time of stent thrombosis after emergency PCI. A 6 month major adverse clinical events comprised death (11%), reinfarction (16%), and recurrent stent thrombosis (12%) after emergency PCI. Multivariable logistic regression analysis identified the achievement of TIMI 3 flow (OR=0.1, CI 95% 0.01-0.54, P<0.001) and diameter stenosis <50% (OR=0.06, CI 95% 0.01-0.32, P<0.001) during emergency PCI to be independently associated with a reduced risk of cardiac death. Recurrent stent thrombosis was independently predicted by the omission of abciximab (OR=4.3, CI 95% 1.1-17.5).

CONCLUSION

Emergency PCI for treatment of stent thrombosis effectively restores vessel patency and flow. Patients presenting with stent thrombosis are at risk for recurrent myocardial infarction and recurrent stent thrombosis.

Relationship of Late Loss in Lumen Diameter to Coronary Restenosis in Sirolimus-Eluting Stents

Background— Observed rates of restenosis after drug-eluting stenting are low (<10%). Identification of a reliable and powerful angiographic end point will be useful in future trials.

Methods and Results— Late loss (postprocedural minimum lumen diameter minus 8-month minimum lumen diameter) was measured in the angiographic cohorts of the SIRIUS (n=703) and E-SIRIUS (n=308) trials. Two techniques, the standard normal approximation and an optimized power transformation, were used to predict binary angiographic restenosis rates and compare them with observed restenosis rates. The mean in-stent late loss observed in the SIRIUS trial was 0.17±0.45 mm (sirolimus) versus 1.00±0.70 mm (control). If a normal distribution was assumed, late loss accurately estimated in-stent binary angiographic restenosis for the control arm (predicted 35.4% versus observed 35.4%) but underestimated it in the sirolimus arm (predicted 0.6% versus observed 3.2%). Power transformation improved the reliability of the estimate in the sirolimus arm (predicted 3.2% [CI 1.0% to 6.7%]) with similar improvements in the E-SIRIUS trial (predicted 4.0% [CI 1.2% to 7.0%] versus observed 3.9%). In the sirolimus-eluting stent arm, in-stent late loss correlated better with target-lesion revascularization than in-segment late loss (c-statistic=0.915 versus 0.665).

Conclusions— Because distributions of late loss with a low mean are right-skewed, the use of a transformation improves the accuracy of predicting low binary restenosis rates. Late loss is monotonically correlated with the probability of restenosis and yields a more efficient estimate of the restenosis process in the era of lower binary restenosis rates.

Clinical and angiographic predictors of luminal changes beyond 6 months after implantation of thicker strut coronary stents

BACKGROUND

Late luminal changes beyond 6 months after thicker strut stent implantation have not been fully elucidated. The purpose of this study was to clarify the clinical and angiographic predictors of late changes in minimal lumen diameter (MLD) after 6-month follow-up of stenting.

METHODS AND RESULTS

Fifty-one lesions from 44 patients who underwent successfully S670/660 stent (Medtronic Vascular, Santa Rosa, CA, USA) implantations without target lesion revascularization were studied at 6-month follow-up and coronary angiography was repeated after the follow-up. Late luminal loss beyond 6 months after stenting significantly correlated with late loss (r=-0.42, p=0.0025) and MLD (r=0.28, p=0.047) at 6-month follow-up. On multivariate analysis, age (p=0.005), diabetes mellitus (p=0.002), hyperlipidemia (p=0.023), smoking (p=0.015), bifurcation lesion (p=0.018), small stent diameter (p=0.001) and MLD at 6-month follow-up (p<0.001) were identified as independent predictors of late luminal loss.

CONCLUSIONS

This study demonstrated that older age, diabetes mellitus, hyperlipidemia, smoking and small stent diameter (<3.0 mm) were associated with late luminal loss beyond 6 months after stenting, and that a bifurcation lesion and small lumen diameter at 6 months were associated with late luminal recovery.

Usefulness of fractional flow reserve in determining the indication of target lesion revascularization

The objective of this study was to examine the usefulness of fractional flow reserve (FFR) in determining the indication of target lesion revascularization (TLR) at follow-up angiography after percutaneous coronary intervention (PCI). One hundred forty-seven patients with 155 lesions that had intermediate restenosis took part in this study. FFR was measured in all patients for the evaluation of stenosis severity. Then TLR was performed when FFR was < 0.75, and TLR was deferred when FFR was > or = 0.75. Patients in whom TLR was deferred were followed up clinically (25 +/- 11 months). In 98 patients (67%) who underwent stress myocardial scintigraphy before angiography, the results of the scintigraphy were compared with FFR results. TLR was performed in 34 lesions (22%). After TLR, the Canadian Cardiovascular Society class decreased significantly (from 1.5 +/- 0.7 to 1.1 +/- 0.5; P < 0.05). In 113 patients who did not undergo TLR, only 4 patients (3.5%) had cardiac events (re-PCI in 1 patient and a positive SPECT in 3 patients). Discordance between the results of scintigraphy and FFR was observed in 30 patients (30%), but the patients who had good values of FFR > or = 0.75 showed a nil event rate (0%). FFR might be useful for the determination of the indication of TLR.

Vascular restenosis - striving for therapy

Restenosis is the limiting entity following coronary angioplasty. It is associated with significant morbidity, mortality and cost, and thus represents a major clinical and economical problem. Despite technical improvements, restenosis after conventional balloon angioplasty occurs in 30 - 60% of cases. Coronary stenting was able to reduce the incidence by approximately 30%; nevertheless, some 250,000 patients experience in-stent restenotic lesions/year worldwide. In-stent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50%, regardless of the angioplasty device used. So far, only vascular brachytherapy has convincingly reduced the incidence of repeat in-stent restenosis (by 50%) and thus, has emerged as the gold standard of therapy. The introduction of drug-eluting stents has shown a great deal of promise for the treatment of both de novo and restenotic lesions, with reported restenosis rates of < 10%, and benefit for virtually all patient subsets at a higher risk of restenosis. This review outlines the pathophysiology, epidemiology and predictors of the restenosis process, and places emphasis on the various treatment options for its prevention and therapy.

Drug-eluting stents: a mechanical and pharmacologic approach to coronary artery disease

Coronary artery disease is the largest killer of men and women in the United States and costs the health care system billions of dollars annually. Several advances in both mechanical and pharmacologic treatment of coronary artery disease have occurred in recent decades. Mechanically, percutaneous coronary intervention is commonly used to treat coronary atherosclerosis. This approach has dramatically reduced both morbidity and mortality for patients with different levels of severity of coronary artery disease. However, percutaneous coronary intervention is limited by restenosis, which is an increase in growth of the intimal layer of the vessel wall. Despite the introduction of intracoronary stents and the addition of systemic pharmacotherapy, restenosis still affects a significant number of patients. The new technology of drug-eluting stents combines mechanical and pharmacologic approaches to prevent restenosis. Various types of these stents exist in different stages of development; several have been shown to prevent or reduce intimal growth after stent deployment. An understanding of how this combined mechanical and pharmacologic approach reduces restenosis requires consideration of complex issues in pathophysiology and pharmacology.

Which Parameter Should Be Chosen as Primary Endpoint for Randomized Drug-Eluting Stent Studies?

In Europe, 1,108 percutaneous coronary interventions (PCIs) per one Mio inhabitants are currently annually performed, most of them with stent implantation. Drug-eluting stents have been the focus of attention of interventional coronary therapy since the RAVEL study was first presented in September 2001 at the European Society of Cardiology Meeting. Ever since, numerous studies have assessed the effects of various antiproliferative and anti-inflammatory substances and a variety of different stents was used as platform, either covered with polymer carriers of different chemical and physical properties or without a polymer carrier. CE- or FDA-certified drug-eluting stents are increasingly replacing the use of bare metal stents to reduce in-stent restenosis. Today, physicians have a choice of several approved drug-eluting stents and, therefore, need some evidence-based guidance through the "jungle of information" to make the right decisions. Even when focusing on randomized trials, differences between the studies regarding primary endpoints and sample sizes exist, making it difficult to compare the various drug-eluting stent studies. Randomized studies use either nonclinical (i.e., angiographic diameter stenosis, in-stent MLD, or in-stent late lumen loss) or clinical (i.e., TVF, TVR, and MACE) parameters as primary endpoints. Choosing an angiographic parameter as primary endpoint results in two major limitations: first, a significant improvement of an angiographic "surrogate" parameter does not necessarily translate into a better clinical outcome (DELIVER-I); second, conclusions regarding possible improvements of clinical outcome are underpowered, because the sample size calculation is based on the primary endpoint. Usually the number of patients needed is lower for angiographic than for clinical endpoints. Until today, only three trials with a primary clinical endpoint have shown a significantly positive impact on patients' outcome: the SIRIUS trial (Cypher stent) with its reduction of primary endpoint TVF (21.0% vs 8.6%), the TAXUS-IV trial (Taxus stent) with its reduction of primary endpoint TVR (12.0% vs 4.7%) and TAXUS-VI in long lesions with its reduction of primary endpoint TVR (19.4% vs 9.1%). Although the angiographic results of other drug-eluting stents are encouraging, they will have to prove their clinical impact based on adequately powered randomized trials with a primary clinical endpoint at an adequate time interval.

Pathological analyses of long-term intracoronary Palmaz-Schatz stenting; Is its efficacy permanent?

BACKGROUND

Angiographic regression of luminal narrowing occurs 6 months to 3 years poststenting. However, after 4 years lesions progressed gradually and late restenosis was observed in 28% of 179 Palmaz-Schatz-stented lesions during the past 10 years. Elucidating its pathogenesis is pivotal to developing preventive strategies.

METHODS AND RESULTS

Histopathological and immunohistochemical studies were performed in 19 stented coronary arteries obtained from 19 patients autopsied after noncardiac death 2-7 years poststenting. The quality/severity of chronic inflammatory cells (T lymphocytes, macrophages and multinucleated giant cells) infiltration around the stent struts that is observed even in the absence of restenosis depended on the time elapsed from stenting: a) 2 years postprocedure, in spite of angiographic regression during the first year and pathologically expressed as maturation of the neointimal scar, there was chronic inflammatory response evidence: neovascularization and lymphocyte infiltration, b) > or = 3 years: the neointimal smooth muscle cells were sparse with abundant proliferation of collagen fibers. Presence of slight helper/inducer T lymphocytes and mild macrophage infiltration around the stent struts was evident immunohistochemically, c) > or = 4 years: prominent infiltration by lipid-laden macrophages with strong collagen-degrading matrix metalloproteinase immunoreactivity was observed around the struts. In two of these arteries, the surface contacting the stent was focally disrupted and covered by nonocclusive mural thrombi.

CONCLUSIONS

Stainless steel stents evoke a remarkable foreign-body inflammatory reaction to the metal. These persistent peri-strut chronic inflammatory cells may accelerate new indolent atherosclerotic changes and consequent plaque vulnerability.

Extracellular Matrix Changes in Stented Human Coronary Arteries

Background— Restenosis after stenting occurs secondary to the accumulation of smooth muscle cells (SMCs) and extracellular matrix (ECM), with the ECM accounting for >50% of the neointimal volume. The composition of the in-stent ECM has not been well characterized in humans.

Methods and Results— Postmortem human coronary arteries (n=45) containing stents underwent histological assessment of neointimal proteoglycans, hyaluronan, collagen (types I and III), SMCs, and CD44 (a cell surface receptor for hyaluronan). The mean duration of stent implantation was 18.7 months; stents in place ≥3 to <9 months (n=17) were assigned to group 1, stents ≥9 to <18 months old (n=19) to group 2, and stents ≥18 months old (n=9) to group 3. In groups 1 and 2, neointimal versican and hyaluronan staining was strongly positive, colocalized with α-actin-positive SMCs, and was greater in intensity compared with group 3. Conversely, decorin staining was greatest in group 3. The neointima of both group 1 and 2 stents was rich in type III collagen, with reduced staining in group 3. Type I collagen staining was weakest in group 1 stents, with progressively stronger staining in groups 2 and 3. SMC density and stent stenosis were significantly reduced in group 3 stents compared with groups 1 and 2. CD44 staining colocalized with macrophages and was associated with increased neointimal thickness.

Conclusions— The ECM within human coronary stents resembles a wound that is not fully healed until 18 months after deployment, followed by neointimal retraction. ECM contraction may be a target for therapies aimed at stent restenosis prevention.

In vitro study of release mechanisms of paclitaxel and rapamycin from drug-incorporated biodegradable stent matrices

We have studied the in vitro release kinetics of two important antirestenosis drugs from biodegradable stent matrices. A helical stent incorporating drugs was exposed to buffer, and both degradation-controlled and diffusion-controlled drug releases were observed. New methods for in vitro drug release for both paclitaxel and rapamycin have been developed. The release profile shows a slow diffusion-controlled phase, followed by a more rapid degradation-controlled region. In the early part of the drug release, no burst effect is observed for either drug. This might be significant for paclitaxel administration, where cardiotoxicity has been sometimes of concern. By suitable polymer/drug formulations, it is possible to develop controlled release stent matrices that can exhibit a variety of release profiles. These release profiles may have relevance to antirestenotic effects and to local or systemic toxic effects.

A comparison of coronary artery stenting with angioplasty for isolated stenosis of the proximal left anterior descending coronary artery: five year clinical follow up

BACKGROUND

Stent implantation for isolated stenosis of the proximal left anterior descending coronary artery (LAD) with preserved left ventricular function has been found to have a better clinical and angiographic outcome at one year than balloon angioplasty (PTCA).

OBJECTIVE

To establish whether those results are maintained at five year follow up.

METHODS

Patients were followed at least every six months. For those who died during follow up, data were obtained from medical records.

MAIN OUTCOME MEASURES

Freedom from death, non-fatal myocardial infarction, cerebrovascular accident, and repeated target lesion revascularisation. Secondary end points were revascularisation in a remote region and freedom from angina.

RESULTS

Follow up was complete in all patients. At five years, the primary end point was reached more often by patients randomised to stent implantation than to PTCA (80% v 53%; odds ratio (OR) 0.29 (95% confidence interval (CI) 0.13 to 0.69); p = 0.0034). In the PTCA group, 35% of patients underwent target lesion revascularisation v 15% in the stent group (OR 0.33, 95% CI 0.13 to 0.80; p = 0.014). There was a trend towards increased mortality in the PTCA group than in the stent group (17% v 7%; OR 0.36, 95% CI 0.10 to 1.21; p = 0.098). No significant differences were found between PTCA and stent groups for non-fatal myocardial infarction (8% v 5%; OR 0.58, 95% CI 0.13 to 2.54; p = 0.46) or cerebrovascular accident (2% v 0%).

CONCLUSIONS

In patients with isolated stenosis of the proximal LAD, a five year clinical follow up confirmed a better outcome in those treated with stenting than with PTCA.

Elective stenting for symptomatic middle cerebral artery stenosis presenting as transient ischaemic deficits or stroke attacks: short term arteriographical and clinical outcome

BACKGROUND

Although stent assisted angioplasty is an effective treatment for coronary and peripheral arterial disease, its efficacy in intracranial arteriosclerotic disease has not been verified.

OBJECTIVES

To assess the radiographic and clinical outcome of stent assisted angioplasty for symptomatic middle cerebral artery (MCA) stenosis.

METHODS

We attempted stent assisted angioplasty in 14 patients with symptomatic high grade stenosis (>60%) on the proximal portion of the MCA, who had experienced either recurrent transient ischaemic attacks (TIAs) resistant to medical therapy or one or more stroke attacks. Patient records were analysed for angiographic characteristics, degree of stenosis, pre-procedural regimen of anti-platelet and/or anti-coagulation agents, use of devices, procedure related complications, pre-operative and post-operative single photon emission computed tomography (SPECT) findings, and clinical and radiographic outcomes.

RESULTS

Stent assisted angioplasty was successfully performed in 8 of 14 patients without any serious complications and unsuccessful in 2 of 14 patients due to the tortuous curve of the internal carotid artery siphon. Four patients had complications. Two patients had an arterial rupture; one patient was rescued by an additional stent and balloon tamponade, the other patient died. Complications in the other two patients included thrombotic occlusion and distal thrombosis. Residual stenosis was less than 50% in diameter in all the patients. All eight patients who underwent follow up cerebral angiography had no restenosis. Follow up SPECT showed improved perfusion in the affected MCA territory in all the tested patients with TIA and in one of three stroke patients. Using the modified Rankin Scale at follow up, four of five TIA patients and five of six stroke patients were assessed as functionally improved or having a stable clinical status.

CONCLUSION

Although the re-stenosis rate in stent assisted angioplasty seems to be better than in primary balloon angioplasty as reported previously, the complication rate is still high. Elective stenting is an alternative therapeutic method for the prevention of secondary ischaemic stroke in stroke patients with MCA stenosis, and seems to be a potentially effective but also hazardous therapeutic technique in patients with recurrent TIAs. This study indicates the need for randomised control trial data of this intervention. Additionally, long term follow up data and additional clinical experience are required to assess the durability of this procedure.

Acute myocardial infarction caused by thrombotic occlusion at a stent site two years after conventional stent implantation

Two cases of acute myocardial infarction caused by thrombotic occlusion at the conventional stented site two years after stenting are described. Late thrombotic stent occlusion may be caused by atherosclerotic regression, sustained inflammatory reaction, and inhibition of proliferation of neointima. Cardiologists must be aware of the potential for late thrombosis following even conventional stent implantation.

Rationale and design of the randomized, multicenter, cilostazol for RESTenosis (CREST) trial

Restenosis of a segment of diseased coronary artery following metallic stenting is a common clinical problem and a major limitation of the procedure. Systemic pharmacologic interventions to deal with this problem have met with little success. Several small studies suggest that cilostazol, a phosphodiesterase III inhibitor whose pharmacologic properties include antiplatelet, antithrombotic, and vasodilatory effects; a beneficial effect on serum lipids; and in vitro inhibition of smooth muscle cell proliferation, may help prevent platelet aggregation and impede the accumulation of new intimal tissue in the stented artery. The Cilostazol for RESTenosis (CREST) trial will aim to evaluate more definitively the ability of cilostazol to prevent restenosis following uncomplicated stent implantation for de novo coronary artery stenosis. In this randomized, double-blind, multicenter study, 700 patients will receive clopidogrel, aspirin, and either cilostazol or placebo after successful intracoronary stent implantation. The primary endpoint is minimal luminal diameter (MLD) of the first lesion stented after 6 months; secondary endpoints include MLD in all lesions, mean percent diameter stenosis, target lesion revascularization, and major angiographic endpoints. Safety endpoints are abnormal complete blood count and liver function tests at 1, 3, and 6 months. The trial has been initiated, and enrollment is anticipated to be concluded in 2003. Cilostazol has properties that may reduce or avert in-stent coronary restenosis. The CREST trial is a large, rigorously conducted trial that may corroborate the favorable effects of cilostazol on coronary stent restenosis suggested by earlier studies.

Quantitative angiographic and intravascular ultrasound study >5 years after directional coronary atherectomy

Aggressive and optimal directional coronary atherectomy (DCA) using intravascular ultrasound (IVUS) guidance provides favorable outcomes within 1 year. However, no previous data are available on the changes that occur in target lesions for the long term after stand-alone DCA. This study's aim evaluates, using quantitative angiography and intravascular ultrasonography, the natural history of changes that occur in target lesions between short- (about 6 months) and long-term (>5 years) follow-up angiography after stand-alone DCA. Of 186 patients (221 lesions) with successful stand-alone DCA, 48 patients (53 lesions) underwent revascularization within 6 months, and 14 patients subsequently died, leaving a study population of 124 patients (154 lesions). Complete quantitative coronary angiography (QCA) was obtained in 91 patients (101 lesions) and complete serial IVUS assessment was obtained for 38 lesions before and after intervention and during follow-up. From short- to long-term follow-up angiography, the minimal luminal diameter significantly increased (from 2.12 to 2.56 mm; p <0.0001); lesion subgroups with >30% diameter stenosis at short-term follow-up angiography showed significant late regression as assessed by QCA. Serial IVUS assessment revealed that the vessel cross-sectional area did not change (from 17.3 to 17.4 mm(2); p = NS); however the lumen cross-sectional area significantly increased (from 7.3 to 9.5 mm(2); p <0.0001) due to the reduction of plaque plus media cross-sectional area (from 10.0 to 7.9 mm(2); p <0.0001). The change in lumen cross-sectional area correlated with the change in plaque plus media cross-sectional area (r = -0.686, p <0.0001). Target lesions show late regression due to plaque reduction at >5 years after stand-alone DCA.

Percutaneous coronary intervention: historical perspectives, current status, and future directions

In the twenty-six years since Gruntzig introduced a simple balloon angioplasty technique, percutaneous coronary intervention has undergone extraordinary growth and has now surpassed bypass surgery in frequency of performance. Several critical breakthrough technologies account for this remarkable progress: intracoronary stents have increased success rates and reduced restenosis, adjunctive antiplatelet therapy has reduced periprocedural complications, and restenosis after stent placement has been effectively treated with local radiation. Most recently, drug-eluting stents coated with cell-cycle inhibitors have shown great promise for further reducing restenosis, possibly to negligible levels.

Long-term outcome after implantation of bare metal stents for the treatment of coronary artery disease: rationale for the clinical use of antiproliferative stent coatings

BACKGROUND

The widespread use of drug-eluting stents in patients with coronary artery disease (CAD) is hampered by unequal regulations for reimbursement. Identification of patients with maximal benefit from this technology may be achieved by assessing long-term clinical outcome after implantation of uncoated bare metal stents.

PATIENTS AND METHODS

A consecutive series of 1,000 patients with CAD treated with bare metal coronary stents of various designs from January 1995 to December 1995 was retrospectively followed over 4 years. The primary end points of the study were major adverse cardiac events.

RESULTS

The mean age of patients was 62 +/- 10.3 years, 77.5% were male, and 18% were diabetic. Clinical follow-up was obtained in 821 patients (82.1%) after 4.6 +/- 1.1 years. During this period of time, 31.8% were admitted for repeat PCI, 15.1% underwent CABG operation, 3.5% had myocardial infarctions, and 3.7% died. At 4 years, 46.3% of diabetic patients survived without event versus 57.6% of nondiabetic patients (P < 0.05). Patients with CAD I survived without event in 65.3% versus 54.0% of patients with CAD II and 48.5% of patients with CAD III (P < 0.02).

CONCLUSION

Implantation of uncoated stents provides the worst long-term clinical outcome in patients with diabetes and those with multivessel CAD. Both groups of patients appear to be primary candidates for the use of drug-eluting stents.

Stent restenosis and the use of drug-eluting stents in patients with diabetes mellitus

Stents have become the technique of choice for percutaneous revascularization, but in-stent restenosis has remained a clinical challenge. This brief article summarizes the incidence, patterns, and proposed mechanisms of restenosis and outlines its contemporary management with specific focus on the diabetic patient. It includes a synopsis of the strategy of drug-eluting stents, which is the most recent and major advance in percutaneous coronary intervention.

Luminal recovery from six to twelve months after implantation of "thicker strut" coronary stents

A group of 50 patients with 51 de novo lesions treated with thicker strut stents (strut thickness >100 microm) was angiographically evaluated at baseline, after stenting, and at 6 and 12 months. Minimal luminal diameter (MLD) significantly increased from 6 to 12 months (6 months: 1.72 +/- 0.50 mm vs 12 months: 1.81 +/- 0.47 mm; p <0.01). The binary restenosis (diameter stenosis >50%) rate was 17% at 6 months and 11% at 12 months (p = NS). At multivariate analysis, lumen loss at 6 months (p = 0.018) and deployment pressure (p = 0.041) independently predicted the changes in MLD between 6 and 12 months.

Late intravascular ultrasound findings of patients treated with brachytherapy for diffuse in-stent restenosis

This study aimed at evaluating long-term (24-month) effects of beta-irradiation (188Re-MAG3-filled balloon) using intravascular ultrasound (IVUS) in patients with in-stent restenosis (ISR). Long-term effects of beta-irradiation on intimal hyperplasia (IH) within the stented segment and vessel and lumen dimensions of nonstented adjacent segments in patients with ISR have not been sufficiently evaluated. Two-year follow-up IVUS was performed in 30 patients with patent ISR segments at 6-month follow-up angiography. Serial IVUS images were acquired at five equidistant intrastent sites and at three different reference segment sites. IH burden (%) was defined as 100 x (IH/stent area). Mean intrastent IH area and IH burden significantly increased between 6 and 24 months, from 2.1 +/- 1.1 to 2.6 +/- 1.4 mm2 (P < 0.001) and from 26% +/- 10% to 33% +/- 14% (P < 0.001), respectively. There was a significant decrease of mean external elastic membrane (from 10.1 +/- 3.9 to 9.7 +/- 3.9 mm2; P = 0.015) and lumen area (from 5.6 +/- 2.3 to 5.1 +/- 2.3 mm2; P = 0.021) within distal reference segments between 6 and 24 months. Target lesion revascularization (TLR) was performed in six patients (20%) between 6 and 24 months after beta-irradiation therapy. There were no significant differences between TLR and non-TLR groups except for a smaller minimum lumen area at 24 months in the TLR group. Because of a small amount of late loss between 6 and 24 months, most irradiated ISR vessel segments remained stable for up to 2 years. However, quantitative evidence of late catch-up was evident in most patients and was significantly associated with 24-month TLR in some patients.

The Drug-Eluting Stent Information Gap

Drug-eluting stents are quickly replacing bare-metal stents as the arterial revascularization device of choice. Because nearly all the information we have about patient outcomes with drug-eluting stents is from trials designed for US Food and Drug Administration approval, we are missing some of the information critical to a more comprehensive understanding of how these new devices will perform at the population level.

Lesion regression after percutaneous coronary intervention for unprotected left main trunk disease

BACKGROUND

Although some studies have documented the six-month angiographic outcomes of percutaneous coronary intervention (PCI) with new devices for unprotected left main trunk disease (ULMTD), a long-term angiographic analysis is mandatory to evaluate the safety and effectiveness of this procedure. This study aims to assess a long-term (one year or more) angiographic analysis after PCI for this lesion.

METHODS

PCI was performed for 225 ULMTD with de novo or restenotic lesions. There were 19 deaths and 12 repeat PCIs during the hospital stay. The remaining 194 lesions were followed, and 126 lesions showed no angiographic restenosis or target lesion revascularization within six months. Finally, long-term quantitative angiographic follow-up was completed in 78 lesions (mean 2.4 years, maximum 7.5 years after PCI).

RESULTS

Minimal lumen diameter increased significantly from 2.46 +/- 0.59 mm to 2.72 +/- 0.65 mm (p < 0.0001) and percent diameter stenosis decreased significantly from 26 +/- 14% to 19 +/- 14% (p < 0.0001) between the six-month and the long-term follow-ups. No additional restenosis or new lesions were found at long-term follow-up, and significant lesion regression was ascertained in each procedure (directional coronary atherectomy, p < 0.005; ballooning, p < 0.005; stenting, p < 0.05).

CONCLUSIONS

These findings support the safety and effectiveness of PCI for ULMTD during the long-term period.

Assessment of coronary arterial stents by multislice-CT angiography

PURPOSE

To assess patency and lumen visibility of coronary artery stents by multislice-CT angiography (MSCTA) in comparison with conventional coronary angiography as the standard of reference.

MATERIAL AND METHODS

47 stents of 13 different types were evaluated in 29 patients. MSCTA was performed on a 4-slice scanner with a standard coronary protocol (detector collimation 4 x 1 mm; table feed 1.5 mm/rotation, 400 mAs, 120 kV). Image evaluation was performed by two readers who were blinded to the reports from the catheter angiography. MIP reconstructions were evaluated for image quality on a 4-point scale (1 = poor, 4 = excellent) and stent patency (contrast distal to the stent as an indirect patency sign). Axial images and multiplanar reformations through the stents were used for assessment of stent lumen visibility (measurement of the visible stent lumen diameter) and detection of relevant in-stent stenosis (> or =50%).

RESULTS

Image quality was fair to good on average (score 2.64 +/- 1.0) and depended on the heart rate (heart rate 45-60: average score 3.2, heart rate 61-70: average score 2.8, heart rate >71: average score 1.4). Thirty-seven stents were correctly classified as patent, 1 was correctly classified as occluded and 9 stents were not assessible due to insufficient image quality because of triggering artifacts. Parts of the stent lumen could be visualized in 30 cases. On average, 20-40% of the stent lumen diameter was visible. Twenty-five stents were correctly classified as having no stenosis, 1 was falsely classified as stenosed, 1 was correctly classified as occluded. In 20 stents lumen visibility was not sufficient for stenosis evaluation.

CONCLUSION

Although the stent lumen may be partly visualized in most stents, a reliable evaluation of in-stent stenoses does not seem practical by 4-slice MSCT. Nevertheless, for stent patency evaluation, MS-CTA might provide valuable clinical information. With submillimeter MSCT (e.g., 16-slice scanners) and more sophisticated reconstruction algorithms, further improvements may be expected.

Sirolimus-eluting stents versus standard stents in patients with stenosis in a native coronary artery

BACKGROUND

Preliminary reports of studies involving simple coronary lesions indicate that a sirolimus-eluting stent significantly reduces the risk of restenosis after percutaneous coronary revascularization.

METHODS

We conducted a randomized, double-blind trial comparing a sirolimus-eluting stent with a standard stent in 1058 patients at 53 centers in the United States who had a newly diagnosed lesion in a native coronary artery. The coronary disease in these patients was complex because of the frequent presence of diabetes (in 26 percent of patients), the high percentage of patients with longer lesions (mean, 14.4 mm), and small vessels (mean, 2.80 mm). The primary end point was failure of the target vessel (a composite of death from cardiac causes, myocardial infarction, and repeated percutaneous or surgical revascularization of the target vessel) within 270 days.

RESULTS

The rate of failure of the target vessel was reduced from 21.0 percent with a standard stent to 8.6 percent with a sirolimus-eluting stent (P<0.001)--a reduction that was driven largely by a decrease in the frequency of the need for revascularization of the target lesion (16.6 percent in the standard-stent group vs. 4.1 percent in the sirolimus-stent group, P<0.001). The frequency of neointimal hyperplasia within the stent was also decreased in the group that received sirolimus-eluting stents, as assessed by both angiography and intravascular ultrasonography. Subgroup analyses revealed a reduction in the rates of angiographic restenosis and target-lesion revascularization in all subgroups examined.

CONCLUSIONS

In this randomized clinical trial involving patients with complex coronary lesions, the use of a sirolimus-eluting stent had a consistent treatment effect, reducing the rates of restenosis and associated clinical events in all subgroups analyzed.

Endovascular rescue from arterial rupture and thrombosis during middle cerebral artery stenting

Intravascular stents are being used with increasing frequency in interventional neuroradiology. Iatrogenic arterial rupture is an uncommon but serious complication. We present a case of arterial rupture and subarachnoid haemorrhage during middle cerebral artery stenting, treated by emergency additional, overlapping stenting and balloon tamponade of the dissected vessel. Thrombotic occlusion of the artery was managed by intra-arterial abciximab. Normal vessel patency was re-established within 20 min and the patient recovered with no neurological deficit.

Coronary stent implantation is superior to balloon angioplasty for chronic coronary occlusions: six-year clinical follow-up of the GISSOC trial

OBJECTIVES

We investigated whether the benefits of stent implantation over balloon percutaneous transluminal coronary angioplasty (PTCA) for treatment of chronic total coronary occlusions (CTO) are maintained in the long term.

BACKGROUND

Several randomized trials have shown that in CTO, stent implantation confers clinical and angiographic mid-term outcomes superior to those observed after PTCA. However, limited information on the long-term results of either technique is available.

METHODS

Six-year clinical follow-up of patients enrolled in the Gruppo Italiano di Studio sullo Stent nelle Occlusioni Coronariche (GISSOC) trial was performed by direct visit or telephone interview. Major adverse cardiac events (MACE), defined as cardiac death, myocardial infarction, target lesion revascularization (TLR), and anginal status, were recorded.

RESULTS

Freedom from MACE at six years was 76.1% in the stent group, compared with 60.4% in the PTCA group (p = 0.0555). This difference was due mainly to TLR-free survival rates (85.1% vs. 65.5% for the stent and PTCA groups, respectively; p = 0.0165). Eleven patients underwent TLR after the nine-month follow-up visit (stent group: n = 5; PTCA group: n = 6); however, in most cases, restenosis of the study occlusion was evident at nine-month angiography.

CONCLUSIONS

This study represents the longest reported clinical follow-up of patients after percutaneous recanalization of CTO and demonstrates that the superiority of stent implantation over balloon PTCA is maintained in the long term. Stent and PTCA results appear to remain stable after nine-month angiographic follow-up. Stent implantation in CTO that can be recanalized percutaneously is therefore a valuable long-term therapeutic option.

Clinical and quantitative angiographic outcomes following elective implantation of the self-expanding Wallstent for longer coronary artery lesions--final results of the Wellstent native study

BACKGROUND: Implantation of short balloon-expandable stents provides superior clinical and angiographic outcome compared with balloon angioplasty in selected patients. The purpose of the Wellstent study was to evaluate the safety and efficacy of the self-expanding Wallstent combined with aspirin and ticlopidine in patients with stable or unstable angina related to a native coronary lesion up to 45 mm in length. METHODS: 105 patients (111 lesions) with stable (57%) or unstable (43%) angina were included in this prospective multicentre evaluation. Angiography before and after Wallstent implantation and at 6-month follow-up was analysed at the core lab using the CAAS 2 system. The primary end-point was incidence of major adverse cardiac events (MACE) at 30 days. Secondary end-points were angiographic outcome at 6 months and MACE at 6 months and 1 year. RESULTS: Acute procedural success (successful stent implantation with residual stenosis <20%) was achieved in 99%. Mean reference diameter was 3.18 +/- 0.66 mm, minimal luminal diameter was 1.00 +/- 0.50 mm pre- and 2.84 +/- 0.47 mm poststent (diameter stenosis 16 +/- 6%). The mean hospital stay was 2.2 days. At 30 days, 95% of patients were free of MACE. At 6 month and 1 year clinical follow-up, 75% and 71% of patients, respectively, remained free of MACE, the majority of which (19 of 30) were re-interventions at re-angiography. In 90% of eligible patients, MLD at follow-up was 1.65 +/- 0.75 mm (late loss 1.20 +/- 0.66 mm, loss index 0.66), diameter stenosis 42 +/- 15%, with a restenosis rate of 32%. Longer stents were associated with greater luminal loss (P = 0.001) and less-favourable clinical outcome. CONCLUSIONS: Wallstent implantation, combined with aspirin and ticlopidine, achieved excellent acute and 30 day clinical results in a heterogenous high-risk patient group. Clinical outcome at 6 months and 1 year remained good, and most adverse events were re-PTCA during follow-up angiography. The loss index of 0.66 and restenosis rate of 32%, related in part to the use of longer stents, emphasizes the continuing need for effective anti-proliferative therapy.

Clinical trends in stent treatment of simple and complex coronary disease

This is a retrospective analysis of a consecutive group of patients from a single medical center who underwent stent implantation. It describes 316 patients who constituted 53% of the angioplasty procedures carried out in a single year. The authors describe the complications and their 1-year follow-up. We aimed to study the short and long-term results of stenting in our centre in relation to multiple clinical and angiographic variables. During 1996, 316 consecutive patients were treated with stent implantation for a total of 381 coronary lesions. The pharmacological protocol methods of stent implantation and patient characteristics were used. Clinical variables were: age 59.1 3 10.7 years, diabetes mellitus 25.3%, hypertension 33.0% and angina pectoris 88.7% (unstable in 44.1%). Previous coronary surgery had been undergone by 9.2%. Multivessel disease was present in 56% of the patients. The indications for stenting were: primary 58.5%, suboptimal results 33.0% and threatened or acute occlusion 8.5%. Angiographic success was 98.9% and clinical success 96.8%. The major in-hospital complications were acute myocardial infarction (2.2%), acute revascularization (0.3%) and major bleeding (0.6%). All occurred within 24 h of revascularization. Repeated angiography was performed in 115 cases (30.2%) at 160.3 3 109.4 days after stent procedure for unstable angina (38.7%), stable angina (26.1%) and other causes (35.2%). The restenosis rate in those catheterized was 38.1%, with an overall clinical restenosis rate of 11.3% during the follow-up period. Restenosis was more prevalent among diabetic patients (17.9 vs 9.15%, P 3 0.02) and patients with prior balloon angioplasty (18.6 vs 9.75%, P 3 0.046). Clinical follow-up was available in 90.8% of the patients for 291 3 112 days. The actuarial survival at the end of the follow-up period was 93.8%. Death/myocardial infarction was associated with unstable angina pectoris (P 3 0.006), hypertension (P 3 0.001), smoking (P 3 0.046) and threatened or acute occlusion (P < 0.001). In the first year of extensive stent use, stenting is associated with high technical and clinical success rates. Long-term results after stent implantation are associated with the occurrence of acute or threatened occlusion, and the in-hospital complications diabetes mellitus and hypertension.

Long-term clinical outcome after stent implantation in coronary arteries

The long-term clinical outcome after planned and unplanned stent implantation was assessed in a single-center, observational study in 178 patients who underwent coronary stent implantation between November 1986 and July 1994. Main outcome measures were survival and event-free survival at 5 years (Kaplan-Meier method). Independent predictors for event-free survival were determined by using multivariate logistic regression analysis. Patients underwent planned (group 1, n 3 101) or unplanned (group 2, n 3 77) stent implantation. During the in-hospital period, there were no deaths. The incidence of Q-wave and non-Q-wave acute myocardial infarction (AMI), coronary artery bypass graft (CABG) and repeat percutaneous transluminal coronary angioplasty (PTCA) was 5.0%, 2.0% and 4.0%, respectively, in group 1, versus 32.5%, 23.4% and 10.4%, respectively, in group 2. During the follow-up period (median 4.0 years, range 0.29-9.8 years), the incidence of death, AMI, and repeat revascularization (CABG and PTCA) was 5.9%, 8.9% and 40.6%, respectively, in group 1, versus 1.3%, 5.2% and 36.4%, respectively, in group 2. Survival and event-free survival at 5 years was 73 (7%) and 47 (7%), respectively, for patients who underwent planned stent implantation. It was 98 (0.1%) and 34 (6%), respectively, for patients who underwent unplanned stent implantation. At the end of follow-up, 31.9% of patients had angina pectoris class III or IV (Canadian Cardiovascular Society). The long-term clinical outcome after both planned and unplanned stent implantation was characterized by a high incidence of repeat revascularization. It is conceivable that changes in stent design and implantation techniques, in addition to novel therapeutic approaches addressing neointima formation and progression of atherosclerosis, may improve the long-term clinical outcome.

Initial single-center experience with a new intracoronary stent

We investigated the safety and efficacy of the recently introduced intracoronary beStent(TM). High flexibility, zero shortening after expansion and delineating gold markers at either end of the stent are favorable features of this device. Between July 1996 and February 1997, 117 patients received a total of 126 stents, measuring 15, 25 and 35 mm in length. The majority of lesions were located in the LAD (n = 48; 38%), followed by lesions in the RCA (n = 41; 33%) and the circumflex artery (n = 28; 22%). Nine additional stents were delivered into vein grafts (7%). Successful stent deployment was achieved in 94% (n = 118), even in cases with complex lesion morphology and angulated segments. The markers proved to be helpful in placing the stent close to side-branches and whenever serial stents were used. Complications during hospitalization were as follows: one cardiac death unrelated to stenting, one subacute stent thrombosis after 30 min of effective anticoagulation and one Q-wave myocardial infarction due to peripheral thrombus embolization after stent placement in a vein graft. One patient was sent for elective CABG after an unsatisfactory procedural result. Stent loss occurred in four patients, and all stents could be retrieved successfully; in another four patients stent placement at the target site was impossible. We conclude that the investigated stent demonstrates several favorable stent characteristics which have proved to be useful in treating complex lesions by providing favorable acute results with a low complication rate.

Coronary stent implantation throughout technical evolution: immediate and follow-up results

Coronary stenting (stent implantation) has evolved over the last 5 years with changes in stent design, stent material and the implantation technique. The use of high-pressure balloon inflation (HP), intravascular ultrasound (IVUS) and appropriate antiplatelet therapy have contributed to the abolishment of the need for subsequent anticoagulation, allowing extended stent applications. We compared results in three groups of patients having stent implantation throughout the period of evolution: group A: no IVUS, no HP, with subsequent anticoagulation treatment (n 3 434); group B: no IVUS, yes HP, without subsequent anticoagulation treatment (n 3 192); and group C: yes IVUS, yes HP, without subsequent anticoagulation treatment (n 3 588). The primary success rates were comparable in all groups. There was a clear change in indications for stenting in groups B and C compared with group A (elective stenting: group A 3 32%; group B 3 66%; group C 3 69%; P < 0.0001), in reference vessel size (group A 3 3.22 3 0.37 mm; group B 3 2.92 3 0.56 mm; group C 3 2.98 3 0.57 mm; P < 0.0001), and for presence of type B2 and C lesions (group A 3 57%; group B 3 72%; group C 3 74%; P < 0.001). The complication rate significantly decreased in group C (group A 3 3.6%; group B 3 4.1%; group C 3 1.2%; P < 0.001) and the mean patient hospital stay decreased to 2 days in groups B and C due to the abolition of the need for anticoagulant treatment. The angiographic restenosis rate increased in groups B and C (group A 3 20%; group B 3 34%; group C 3 32%; P < 0.001). The need for a repeat procedure increased as stenting of more complex lesions and smaller vessels was attempted: target lesion revascularization (TLR) was performed in 16% of patients in group A (73/434), in 18% of group B (35/192) and in 22% of group C (129/588) (P 3 0.04 for A versus C). Major cardiac events (MACE) occurred in 142 patients in group A (33%), 60 patients in group B (31%) and in 181 patients in group C (30%). The evolving technique of coronary stenting has expanded the spectrum of indications and range of coronary vessels attempted, and decreased the complication rates and hospital stay. However, in less-favorable subsets, additional improvements are needed to affect the long-term outcome.

Clinical and economic outcomes of multivessel coronary stenting compared with bypass surgery: a single-center US experience

BACKGROUND

Randomized trials comparing multivessel stenting with coronary artery bypass surgery (CABG) have demonstrated similar rates of death and myocardial infarction but higher rates of repeat revascularization after stenting. The impact of these alternative strategies on overall medical care costs is uncertain, particularly within the US health care system.

METHODS

We performed a retrospective, matched cohort study to compare the clinical and economic outcomes of multivessel stenting and bypass surgery. The stent group consisted of 100 consecutive patients who underwent stenting of >or=2 major native coronary arteries at our institution. The CABG group consisted of 200 patients who underwent nonemergent isolated bypass surgery during the same time frame, matched (2:1) for age, sex, ejection fraction, diabetes mellitus, and extent of coronary disease. Detailed clinical follow-up and resource utilization data were collected for a minimum of 2 years. Total costs were calculated by use of year 2000 unit prices.

RESULTS

Over a median follow up period of 2.8 years, there were no significant differences in all-cause mortality rates (3.0% vs 3.0%), Q-wave myocardial infarction (5.1% vs 4.0%), or the composite of death or myocardial infarction (7.1% vs 7.0%) between the stent and CABG groups (P = not significant for all comparisons). However, at 2-year follow up, patients with stents were more likely to require >or=1 repeat revascularization procedure (32.0% vs 4.5%, P <.001). The initial cost of multivessel stenting was 43% less than the cost of CABG (11,810 dollars vs 20,574 dollars, P <.001) and remained 27% less (17,634 dollars vs 24,288 dollars, P =.005) at 2 years.

CONCLUSIONS

Multivessel stenting and CABG result in comparable risks of death and myocardial infarction. Despite a higher rate of repeat revascularization, multivessel stenting was significantly less costly than CABG through the first 2 years of follow-up.

Low restenosis rate of the NIR coronary stent: results of the Danish multicenter stent study (DANSTENT)--a randomized trial comparing a first-generation stent with a second-generation stent

BACKGROUND

Larger studies evaluating the angiographic results of second-generation stents are scarce. The objectives of this study were to assess current standards of angiographic and clinical outcomes after implantation of the second-generation stainless steel stent, NIR (Medinol Ltd, Tel Aviv, Israel), and to compare the outcomes with those of the first-generation Palmaz-Schatz (PS) stent (Johnson & Johnson, Warren, NJ).

METHODS

Patients having coronary artery lesions that could be covered by a stent of 15 mm in length were randomly assigned to receive the NIR or the PS. Procedural success, 6-month angiographic findings, and 1-year clinical outcomes were determined.

RESULTS

In 424 patients included in the study, the overall procedural success rate was high (NIR 98%, PS 99%, P =.90). Follow-up angiography was conducted in 91% of the patients. The overall rate of angiographic restenosis was low in both groups (NIR 9.9%, PS 12.6%, P =.35). We found a low restenosis rate in vessels with a minimal lumen diameter >3.1 mm after the procedure, particularly in the NIR group (<6%). The rate of target lesion revascularization after 1 year did not differ (NIR 12%, PS 10%, P =.47).

CONCLUSIONS

The angiographic and clinical outcomes after implantation of the second-generation stainless steel stent were not significantly better than those of the first-generation stent. The low restenosis rates, particularly in patients with the largest minimal lumen diameters after stent implantation, warrants circumspection when planning the evaluation of newer stent technologies that aim to further reduce coronary restenosis.

Directional coronary atherectomy vs. rotational atherectomy for the treatment of in-stent restenosis of native coronary arteries

Management of in-stent restenosis has become a significant challenge in interventional cardiology. Since the mechanism of in-stent restenosis is predominantly intimal hyperplasia, debulking techniques have been used to treat this condition. This study is a nonrandomized comparison of the immediate and long-term results of directional coronary atherectomy (DCA; n = 58) vs. high-speed rotational atherectomy (ROTA; n = 61) for the treatment of in-stent restenosis of native coronary arteries. There were no in-hospital deaths, Q-wave myocardial infarctions, or emergency coronary artery bypass surgery in either group. DCA resulted in a larger postprocedural minimal luminal diameter of (2.57 +/- 0.51 vs. 2.14 +/- 0.37 mm; P < 0.0001) and a larger acute gain (1.83 +/- 0.52 vs. 1.42 +/- 0.48 mm; P < 0.0001). Furthermore, 12-month clinically indicated target lesion revascularization (39% vs. 21%; P = 0.02) and long-term follow-up MACE (44% vs. 28%; P = 0.03) was greater in the ROTA group. The present study suggests that DCA appears to be superior to ROTA for the treatment of in-stent restenosis of native coronary arteries. Compared to ROTA, the debulking effect of DCA leads to a larger postprocedure minimal luminal diameter, and a lower incidence of subsequent target lesion revascularization and MACE.

Two-year angiographic and intravascular ultrasound follow-up after implantation of sirolimus-eluting stents in human coronary arteries

BACKGROUND

The safety and efficacy of sirolimus-eluting stenting have been demonstrated, but the outcome of patients treated with this novel technology beyond the first year remains unknown. We sought to evaluate the angiographic, intravascular ultrasound (IVUS), and clinical outcomes of patients treated with sirolimus-eluting stents 2 years after implantation.

METHODS AND RESULTS

This study included 30 patients treated with sirolimus-eluting Bx Velocity stenting (slow release [SR], n=15, and fast release [FR], n=15) in São Paulo, Brazil. Twenty-eight patients underwent 2-year angiographic and IVUS follow-up. No deaths occurred during the study period. In-stent late loss was slightly greater in the FR group (0.28+/-0.4 mm) than in the SR group (-0.09+/-0.23 mm, P=0.007). No patient had in-stent restenosis. At 2-year follow-up, only 1 patient (FR group) had a 52% diameter stenosis within the lesion segment, which required repeat revascularization. The target-vessel revascularization rate for the entire cohort was 10% (3/30) at 2 years. All other patients had < or =35% diameter stenosis. Angiographic lumen loss at the stent edges was also minimal (in-lesion late loss was 0.33+/-0.42 mm [FR] and 0.13+/-0.29 mm [SR]). In-stent neointimal hyperplasia volume, as detected by IVUS, remained minimal after 2 years (FR= 9.90+/-9 mm3 and SR=10.35+/-9.3 mm3).

CONCLUSIONS

This study demonstrates the safety and efficacy of sirolimus-eluting Bx Velocity stents 2 years after implantation in humans. In-stent lumen dimensions remained essentially unchanged at 2-year follow-up in the 2 groups, although angiographic lumen loss was slightly higher in the FR group. Restenosis "catch-up" was not found in our patient population.

Area ablation: a new lasing concept provides significantly enhanced acute and long-term results for treatment of in-stent restenosis

BACKGROUND AND OBJECTIVES

Debulking is still a technique of choice for in-stent restenosis (ISR). Excimer laser debulking has enabled high procedural success with very low complication rates, but has demonstrated markedly heterogeneous results owing to differences in lasing and laser technology, and selected patient populations. Since new area-ablation technique enables ablation of larger areas than its own device size, we have evaluated their effectiveness and safety in an uncontrolled study.

STUDY DESIGN/MATERIALS AND METHODS

Fifty-three patients with diffuse ISR were treated by laser area ablation, followed by adjunctive balloon angioplasty. Primary endpoint was percent of binary stenosis at 6-month follow-up; secondary endpoints were procedural success; target lesion revascularization (TLR); major adverse cardiac events (MACE); diameter stenosis (DS); and minimal lumen diameter (MLD) before and after laser debulking, and at 6-month follow-up.

RESULTS

Laser debulking was feasible (as defined as < or =30% residual stenosis) in 98.1% of patients. At 6-month follow-up, binary stenosis was 26.4%; angiographic TLR, 20.7%; and MACE, 3.7%. DS decreased from 87+/-17% to 20 +/- 9% after laser debulking, and to 9+/-7% after PTCA; it was 29+/-14% at follow-up (P-values in comparison to baseline: 0.0047; 0.0036; 0.0064). MLD increased from 0.6+/-0.3 to 2.4+/-0.5 mm after laser debulking, to 2.8+/- 0.6 mm after adjunctive PTCA, and to 1.9 +/- 0.4 mm at follow-up (P-values in comparison to baseline: 0.0059; 0.0031; 0.0088).

CONCLUSIONS

Owing to a significantly greater MLD, area ablation facilitates significantly enhanced immediate and follow-up results for diffuse ISR, including a simpler and more effective laser-debulking procedure than former lasing techniques.

Long-term (three-year) outcomes after stenting of unprotected left main coronary artery stenosis in patients with normal left ventricular function

The purpose of this study was to analyze long-term follow-up information from patients treated with stenting for unprotected left main coronary artery (LMCA) stenosis. Stenting of unprotected LMCA stenosis is often performed in selected patients, but the long-term safety of this therapy is not yet established. Between January 1995 and September 2000, 270 consecutive patients with unprotected LMCA stenosis and normal left ventricular function who underwent treatment at 4 clinical centers were included in this study. Data were forwarded to the coordinating center using a standard case report form. The procedural success rate was 98.9%. There were no deaths, 3 stent thromboses, and 3 Q-wave myocardial infarctions during the hospitalization. Angiographic follow-up was performed in 237 patients (follow-up rate 87.8%), and the restenosis rate was 21.1%. The reference size was an independent predictor of binary restenosis (odds ratio 0.543, 95% confidence interval 0.308 to 0.957, p = 0.03). During the follow-up period (32.3 +/- 18.5 months), there were 20 deaths (8 cardiac, 12 noncardiac) and 5 nonfatal myocardial infarctions. Target and new lesion revascularizations were required in 45 (16.7%) and 31 (11.5%) patients, respectively. The cumulative probabilities free from major adverse cardiac events were 81.9 +/- 2.4%, 78.4 +/- 2.6%, and 77.7 +/- 2.7%, respectively, at 1, 2, and 3 years. Combined coronary artery disease and postprocedural minimal luminal diameter were the significant predictors of major adverse cardiac events. Thus, the long-term prognosis of patients after stenting of unprotected LMCA stenosis was favorable in selected patients with normal left ventricular function.

Clinical restenosis after coronary stenting: perspectives from multicenter clinical trials

OBJECTIVES

We sought to evaluate clinical restenosis in a large population of patients who had undergone coronary stent placement.

BACKGROUND

One-year success after coronary stenting is limited mainly by restenosis of and requirement for repeat revascularization of the treated lesion. We studied 6,186 patients (6,219 lesions) pooled from several recently completed coronary stent trials. Clinical restenosis was defined using three different definitions: target lesion revascularization (TLR) beyond 30 days, target vessel revascularization (TVR) beyond 30 days, and target vessel failure (TVF), defined as TVR, any death, or myocardial infarction (MI) of the target vessel territory after hospital discharge.

RESULTS

By one year, 638 (12.2%) patients had TLR, 748 (14.3%) had TVR, and 848 (16.0%) had TVF, more than two-thirds higher than the rate of these end points at six months. The severity of angiographic restenosis (> or =50% follow-up diameter stenosis [DS]) in 419 of 1,437 (29%) patients undergoing routine angiographic follow-up correlated directly with the likelihood of TLR (73% vs. 26% for >70% DS compared with <60% DS). Smaller pretreatment minimum lumen diameter (MLD), smaller final MLD, longer stent length, diabetes mellitus, unstable angina, and hypertension were independent predictors of TLR. Prior MI and current smoking were negative predictors.

CONCLUSIONS

At one year after stenting, most clinical restenosis reflected TLR, which was predicted by the same variables previously associated with an increased risk of angiographic restenosis. The lower absolute rate of clinical restenosis relative to angiographic restenosis was due to infrequent TLR in lesions with less severe (<60% DS) angiographic renarrowing.

Clinical and angiographic outcome after conventional angioplasty with optional stent implantation compared with direct stenting without predilatation

OBJECTIVE

To compare in a randomised trial the procedural and clinical outcome and long term patency of conventional angioplasty with optional stent implantation versus direct stenting without predilatation.

METHODS

Patients undergoing coronary intervention for symptomatic coronary artery disease were randomly assigned to conventional angioplasty with optional stenting or to direct stent implantation without predilatation. The post-stent treatment consisted of antiplatelets. Follow up angiography was performed six months after the initial procedure.

RESULTS

Between December 1998 and August 1999, 181 of 190 eligible patients were randomly assigned to either optional stenting (n = 92) or direct stenting (n = 89). The procedural success was similar in both groups (87 (97.8%) in the optional v 87 (94.6%) in direct stenting group, p = 0.88). There were five cases of crossover from the direct stenting to the optional stenting group. Six patients experienced a Q wave myocardial infarction without further complications (4 in the optional v 2 in the direct stenting group, p = 0.36). One patient in whom coronary angioplasty failed underwent elective bypass surgery. No patients required urgent bypass surgery and no patients died. The reduction in late luminal loss (mean (SD) 1.19 (0.87) mm in the optional v 0.62 (0.69) mm in the direct stenting group, p = 0.004) led to a significant improvement in minimal luminal diameter at follow up (1.87 (0.93) mm in the optional v 2.56 (0.86) mm in the direct stenting group, p = 0.002), resulting in a significant reduction in restenosis rate, defined as > 50% diameter stenosis at follow up 6.5 (2.1) months after the initial procedure (28 (30.4%) in the optional v 14 (15.7%) in the direct stenting group, p = 0.019). Direct stenting significantly reduced the overall procedure and fluoroscopy times, the amount of contrast medium used, and the number of angioplasty catheters needed. The incidence of clinical events during the six month follow up did not differ significantly between the groups. No patient died during follow up.

CONCLUSIONS

Direct stent implantation without predilatation significantly reduced late luminal loss, giving a better improvement in minimal luminal diameter and restenosis rate than with optional stenting. There were five patients in whom direct stenting failed who needed predilatation followed by stent implantation. However, in most patients direct stent implantation without predilatation is a feasible treatment option with a favourable long term outcome and a low incidence of complication. The procedure may help to reduce the cost of coronary interventions by reducing overall procedure and fluoroscopy times, the amount of contrast medium used, and the number of angiography catheters needed.

Neointima in coronary stent does not increase during over 1-year in non-restenosed lesion at 6 months follow-up: serial volumetric intravascular ultrasound study

The long-term outcomes of coronary artery stenting have been determined by coronary angiography only with has the limitation of determining stent expansion and neointimal proliferation at long-term follow-up. Volumetric intravascular analysis has the potential to evaluate the morphology and distribution of neointima longitudinally after coronary artery stenting. We used three-dimensional intravascular ultrasound (3-D IVUS) to evaluate serial changes in stent and neointimal volumes for over 1-year in 9 patients who did not exhibit angiographic restenosis at 6-month follow-up. Volumetric analysis by a validated Netra 3-D IVUS system was performed pre- and post-intervention, at 6-month follow-up (FU1), and at over one-year follow-up (FU2). Lumen volume in the stented lesions increased significantly after intervention, and the increase persisted until FU2. There were no significant changes in stent volume between just after stent implantation and at FU2. Neointimal volume within the stents did not change from FUI to FU2 (FU1; 38.4 +/- 9.0 mm3 vs FU2; 33.8 +/- 10.3 mm3). In 33% (3/9) of all lesions, neointimal volume increased between from 6-months to over 1-year after stent implantation. Neointimal distribution after stenting seemed to be almost equal and unrelated to the plaque burden at pre-intervention. Neointimal volume within the stents did not increase and stent volume did not change over the 1st-year in patients who did not exhibit angiographic restenosis at 6-months.

Persistent Inhibition of Neointimal Hyperplasia After Sirolimus-Eluting Stent Implantation

Background— Early results of sirolimus-eluting stent implantation showed a nearly complete abolition of neointimal hyperplasia. The question remains, however, whether the early promising results will still be evident at long-term follow-up. The objective of our study was to evaluate the efficiency of sirolimus-eluting stent implantation for up to 2 years of follow-up.

Methods and Results— Fifteen patients with de novo coronary artery disease were treated with 18-mm sirolimus-eluting Bx-Velocity stents (Cordis) loaded with 140 μg sirolimus/cm 2 metal surface area in a slow release formulation. Quantitative angiography (QCA) and intravascular ultrasound (IVUS) were performed according to standard protocol. Sirolimus-eluting stent implantation was successful in all 15 patients. During the in-hospital course, 1 patient died of cerebral hemorrhage after periprocedural administration of abciximab, and 1 patient underwent repeat stenting after 2 hours because of edge dissection that led to acute occlusion. Through 6 months and up to 2 years of follow-up, no additional events occurred. QCA analysis revealed no significant change in stent minimal lumen diameter or percent diameter stenosis, and 3-dimensional IVUS showed no significant deterioration in lumen volume. In 2 patients, additional stenting was performed because of significant lesion progression remote from the sirolimus-eluting stent.

Conclusion— Sirolimus-eluting stents showed persistent inhibition of neointimal hyperplasia for up to 2 years of follow-up.

Can we prevent in-stent restenosis?

Nowadays stent placement has replaced balloon angioplasty as the most commonly performed percutaneous coronary interventional procedure, mainly because of its better acute and chronic outcome. As a result, in-stent restenosis (ISR) has become a widespread problem. The incidence of ISR varies from 10% to 50% and depends on the absence or presence of several risk factors, such as small vessel size, longer lesions, and diabetes. Intravascular ultrasound studies have demonstrated that ISR is mainly caused by neointimal proliferation; consequently, this pathologic process has become the target of many preventive and therapeutic approaches. This article provides an overview of such management strategies, highlighting the rather disappointing experiences with mechanical and systemic drug therapies; the relative merits and disadvantages of intracoronary radiation; and the exciting yet realistic promise, embodied by the recent advancements in drug-eluting stent technology, of potentially eradicating ISR in the near future.