Utilization of the coronary balloon-expandable coil stent without anticoagulation or intravascular ultrasound

Safety and efficacy of angiography-guided stent placement in small native coronary arteries of < 3.0 mm in diameter

BACKGROUND AND HYPOTHESIS

Increased operator experience, greater insight in stent deployment techniques, and improved poststent medication regimen have significantly reduced the risk of thrombotic stent closure following stent placement in large coronary arteries (> or = 3.0 mm in diameter). Whether equally favorable results are afforded by stent placement in small vessels (< 3.0 mm), however, remains unclear. Accordingly, the aim of this study was the specific examination of the risk of stent placement in small native coronary vessels, using stent deployment technique consisting of supplementary dilatations with larger balloons or high-pressure inflations, and aggressive aspirin-ticlopidine and short-term oral anticoagulation poststent therapy.

METHODS

Forty-seven balloon-expandable stents (20 Gianturco-Roubin, 21 NIR, 6 Palmaz-Schatz) were successfully implanted without intravascular guidance in 45 native coronary arteries (mean reference diameter of 2.5 mm) in 44 consecutive patients (31 men, 13 men), the majority of whom (87%) were stented for the treatment of failed or suboptimal balloon angioplasty outcome.

RESULTS

Successful stent placement reduced the lesion diameter stenosis from 91 +/- 9% to 3 +/- 7% (p = 0.0001). There were no early stent thrombosis or major cardiovascular events prior to hospital discharge. During a 12-month follow-up period, most patients remained symptomatically improved and no myocardial infarction, stroke, or death was observed. Five-month angiographic reassessment revealed an in-stent restenosis rate of 41%, which was higher in vessels < or = 2.5 mm in size (47 vs. 33% for vessels > 2.5 mm, p = 0.2747).

CONCLUSIONS

In selected patients with small native coronary vessels < 3.0 mm in diameter, angiography-guided optimal stent placement is associated with a low risk of stent thrombosis and bleeding complications. However, the in-stent restenosis rate is high with the stents used in this study.

Angiographic and clinical outcome following sirolimus-eluting stent (Cypher) implantation. A single center experience

OBJECTIVES

To investigate the late outcomes of sirolimus-eluting stent implantation in patients with coronary artery disease.

BACKGROUND

Drug-eluting stents reduce intimal hyperplasia, which is the main cause of in-stent restenosis. Sirolimus-eluting stents significantly reduce clinical and angiographic restenosis and improve event-free survival.

METHODS

The study population consisted of 207 patients (273 stents) who had undergone coronary Cypher stent implantation. Patients were eligible for enrollment if there was symptomatic coronary artery disease or positive exercise testing, and angiographic evidence of single or multivessel disease with a target lesion stenosis of > or = 70% in a > or = 2.25 mm vessel. Follow-up coronary angiography was performed 18 months after stent deployment. Patients were followed-up for a mean of 24.7 +/- 7.4 months.

RESULTS

All patients survived after stent implantation, but 5 (2.4%) patients experienced acute ST elevation myocardial infarction and 4 (1.9%) patients developed non-Q wave myocardial infarction following angioplasty. Recurrent angina pectoris was observed in 16 (7.7%) patients (11 stable angina pectoris and 5 unstable angina pectoris). Angiographic evidence of restenosis was observed in these 20 (9.66%) patients. The 5 other patients had noncritical angiographic restenosis. Eleven (5.3%) patients underwent angioplasty because of restenosis, and coronary artery bypass grafting was conducted in the other 9 (4.3%) patients.

CONCLUSION

The results of the present study indicate that Cypher stents could be implanted with a very high success rate and have encouraging long-term angiographic and clinical results.

Routine intravascular ultrasound scanning guidance of coronary stenting is not associated with improved clinical outcomes

PURPOSE

The purpose of the current study was to determine whether there is any incremental benefit to routine intravascular ultrasound (IVUS) guidance of percutaneous coronary intervention.

METHODS AND RESULTS

We compared the outcome of 796 patients who underwent an IVUS study (IVUS group) during the index stent procedure with 8274 patients who did not have an IVUS study (angiography group). The primary end point was the composite end point of death, myocardial infarction, or ischemia-driven target vessel revascularization within 9 months of the index stent procedure. There were statistically significant differences in multiple procedural characteristics. Most importantly, those patients who underwent an IVUS study had a larger postprocedural minimal lumen diameter and smaller postprocedural percent diameter stenosis. However, there was no significant difference between the IVUS group and the angiography group with respect to the primary end point (RR 1.10, 95% CI 0.91, 1.32) or any of the individual clinical end points. Adjustment for multiple clinical and procedural characteristics did not significantly alter these findings.

CONCLUSIONS

These data suggest that the routine performance of IVUS during stent placement influences the performance of the procedure, as judged by differences in procedural characteristics, but does not improve clinical outcome at 9 months.

Routine intravascular ultrasound guidance of percutaneous coronary intervention

Intravascular ultrasound (IVUS) has played an integral role in the evolution of interventional cardiology. However, routine IVUS guidance of coronary stent implantation is not supported by a critical reappraisal of the available evidence. Although there is a trend toward a benefit with respect to target lumen revascularization favoring IVUS-guided coronary stent implantation, it is likely that this effect is driven by improved outcomes in small vessels, long coronary stenoses, and possibly saphenous vein graft interventions. No consistent trend in the incidence of death or myocardial infarction is apparent. Furthermore, the safety, efficacy, and effectiveness of IVUS should be taken into account when considering the goals, risks, benefits, and alternatives to such a treatment strategy.

Impact of intravascular ultrasound-guided stenting on long-term clinical outcome: a meta-analysis of available studies comparing intravascular ultrasound-guided and angiographically guided stenting

To date, only a few studies have compared the clinical efficacy of intracoronary ultrasound (IVUS)-guided to angiographically guided stenting. Furthermore, it is not yet known whether the lower restenosis rate shown with the former strategy would translate into a substantial clinical advantage. Therefore, the aim of the present investigation was to improve the level of evidence of these studies by means of a formal meta-analysis. Nine studies were considered suitable for analysis. Odds ratios (ORs) were calculated for 6-month clinical follow-up. Primary endpoint was a composite of death and nonfatal myocardial infarction (MI), as considered in every single study. Secondary endpoints were major adverse cardiac events (MACEs), according to single study definition, the individual cardiac events, as well as several pre- and postprocedure and follow-up angiographic parameters. Overall, 2,972 patients were included. At 6 months, the OR for death and nonfatal MI was 1.13 (95% CI = 0.79-1.61; P = 0.5) for patients with IVUS-guided stenting. However, patients with IVUS-guided stenting had less target vessel revascularizations (OR = 0.62; 95% CI = 0.49-0.78; P = 0.00003) and MACEs (OR = 0.79; 95% CI = 0.64-0.98; P = 0.03) compared to angiographically guided stenting. In addition, subjects treated with IVUS-guided stenting had significantly less binary restenosis (OR = 0.75; 95% CI = 0.60-0.94; P = 0.01). The present meta-analysis demonstrates that IVUS-guided stenting implantation has a neutral effect on long-term death and nonfatal MI compared to an angiographic optimization. However, IVUS-guided stenting significantly lowers 6-month angiographic restenosis and target vessel revascularizations. Whether these benefits could be very helpful when dealing with lesions at high risk for restenosis is still an issue.

Is adjunctive balloon postdilatation necessary after coronary stent deployment? Final results from the POSTIT trial

Early-generation balloon-expandable stents required postdilatation with noncompliant balloons at high pressure to optimize stent deployment. The need for adjunctive balloon postdilatation with modern stent delivery systems is unknown. Patients undergoing elective stenting were randomized to Boston Scientific NIR, Guidant Tri-Star/Tetra, and Medtronic AVE S670 stents. The primary endpoint was optimum stent deployment defined as a minimal stent diameter (MSD) >/= 90% of the average reference lumen diameter assessed by intravascular ultrasound (IVUS) performed immediately following stent deployment. If, by operator assessment, the primary endpoint was not achieved with the stent delivery system, adjunctive postdilatation with noncompliant balloons was performed. Of 256 patients with IVUS studies adequate for core laboratory analysis, only 29% achieved optimum stent deployment with the stent delivery system. None of the baseline clinical or angiographic variables predicted optimum stent deployment. Of the procedural variables, the type of stent and nominal stent size were not predictors, but higher deployment pressures were associated with a higher frequency of optimum stent deployment (< 12 atm 14% vs. >/= 12 atm 36%; P = 0.007). The inability to achieve optimum stent deployment was not due to undersizing the stent delivery balloon, but rather to an inability of the stent delivery balloon to expand fully the stent to nominal size. In patients who underwent postdilatation, the frequency of achieving optimum stent deployment increased from 21% to 42%, minimal stent area increased from 6.6 +/- 2.2 to 7.8 +/- 2.3 mm(2), and MSD increased from 2.6 +/- 0.5 to 2.8 +/- 0.4 mm. These data stress the continued need for adjunctive balloon postdilatation with modern stent delivery systems. Cathet Cardiovasc Intervent 2003;59:184-192.

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.

Angiography-guided routine coronary stent implantation results in suboptimal dilatation

The resistance of the atherosclerotic lesion counteracts the expansion of the stent, resulting in suboptimal stent expansion. Intravascular ultrasound provides more precise information on stent expansion than coronary angiography but adds cost and time to the percutaneous transluminal coronary angiography procedure. The aim of this study was to evaluate the need for intravascular ultrasound at routine angiography-guided high pressure stent implantation by comparing stent expansion with predefined intracoronary ultrasound criteria for optimal stent implantation. In 32 patients, 48 stents (35 NIR, 12 AVE, and 1 Cordis) were implanted in A, B, and C stenoses using a high-pressure inflation technique until an optimal result was achieved according to angiography. Stent expansion was then evaluated by intravascular ultrasound as minimal lumen diameter, minimal lumen area, proximal and distal stent area, and a minimal lumen area symmetry index. These variables were then compared with the nominal stent size in vitro. Finally the stents were also evaluated with respect to the MUSIC criteria, ie, strict criteria regarding symmetry, apposition, and vessel geometry according to intravascular ultrasound after stent expansion. Forty-five stents could be completely analyzed. The mean balloon inflation pressure was 12.8 (range, 10-17) atm. The nominal stent size was not achieved in any patient. Minimal lumen diameter attained 77% and minimal lumen area 78% of expected nominal values (p<0.0001), distal stent area 88% (p < 0.001), and proximal stent area 92% (ns). Application of the MUSIC criteria showed that almost all stents (96%) had good stent apposition and symmetry index. Optimal proximal stent entrance was found in 70%. Optimal minimal lumen area in comparison to the reference areas was present in 41%. This lead to fulfilling of all MUSIC criteria in 47% of the stents. If nominal stent size had been achieved, symmetry index and apposition would have been fulfilled in all cases and optimal minimal lumen area increased to 75%. Acceptable proximal entrance however would have decreased to 55% and the fulfillment of all MUSIC criteria would increase only to 52%. In routine angiography-guided stent implantation in stenoses with a wide range of severities using modern stents and high pressure inflation technique to reach a visually optimal result, the nominal stent size was never achieved mainly due to residual intrastent stenosis. If nominal stent size had been achieved, the results would have improved only marginally and would still be suboptimal in almost half of the stents. These results highlight the shortcoming of angiography and the need for intravascular ultrasound in choosing correct stent size.

Efficacy of postdeployment balloon dilatation for current generation stents as assessed by intravascular ultrasound

Adjunctive balloon dilatation strategy has been shown to improve optimal stent deployment. As improvements in current stent designs evolve, less adjunctive balloon dilatation may be needed. However, few data currently exist to support this practice. We evaluated 88 native coronary lesions treated with single stent implantation (Nir, Tristar or S670). Serial intravascular ultrasound was performed after successful stent deployment and again after adjunctive balloon dilatation. To investigate further the precise expansion characteristics of the stents, serial volumetric intravascular ultrasound analyses were performed in 40 patients with automated pullback. After adjunctive balloon dilatation, minimal stent area increased significantly, from 6.4 +/- 2.1 to 7.4 +/- 2.2 mm(2) (p <0.001). Volumetric analysis showed a corresponding increase in stent volume index (6.6 +/- 1.8 to 7.5 +/- 2.0 mm(3)/mm, p <0.001). In the analysis of cross sections at 0.5-mm axial intervals, the percentage of cross sections, where stent area was > or =80% of the average reference lumen area, increased from 51% to 78% (p <0.001). Similarly, the percentage of cross sections, where stent area was > or =90% of the average reference lumen area, increased from 29% to 56% (p <0.001) with postdilatation. Postdeployment high- pressure balloon dilatation improved minimal stent area and volumetric expansion throughout the stented segment.

Prognostic value of absolute versus relative measures of the procedural result after successful coronary stenting: importance of vessel size in predicting long-term freedom from target vessel revascularization

BACKGROUND

The procedural result is a major determinant of the incidence of 6-month target vessel revascularization (TVR) after successful coronary stenting. However, the prognostic implications of the different measures of the procedural result or procedural end points have not been directly compared. In this study, we sought to assess and compare the impact of achieving different procedural end points on the long-term (2-year) incidence of TVR.

METHODS AND RESULTS

We studied 234 patients in whom 1 or 2 stents were successfully deployed and ultrasound imaging performed after angiographic optimization. End points included a visually estimated angiographic residual stenosis <10% and ultrasound stent-to-mean reference lumen area > or = 80%. After 2 years, TVR was required in 48 (20.5%) patients. Qualitative predictors of TVR were vein graft lesions, 3-vessel disease, and baseline TIMI flow grade < 3. Quantitatively, reference diameter by quantitative coronary angiography (QCA), final minimum lumen diameter (MLD) by QCA, and in-stent minimum lumen area (MLA) by ultrasound were predictive of TVR. Stent-to-reference ratios were not significantly predictive of TVR. By multivariable analysis, vein graft location and MLA by ultrasound were the only significant predictors of TVR (relative risk, 2.9 [1.5, 5.4] and 0.72 [0.6, 0.9], respectively). Receiver operator curves for MLD by QCA and MLA by ultrasound were similar in predicting TVR. Neither was significantly superior to reference vessel diameter.

CONCLUSIONS

Commonly used angiographic and ultrasound stent-to-reference ratios do not predict the incidence of TVR. Absolute measures of the lumen size (MLA by ultrasound and MLD by QCA) were the most important quantitative predictors of TVR within 2 years. This emphasizes the role of the vessel size as the limiting factor in determining the long-term outcome of coronary stenting.

Early and mid-term angiographic and clinical results after intracoronary duet stent placement

The Duet stent (Guidant/Advanced Cardiovascular Systems) is a new stent with a corrugated ring design and very limited data on its short- and mid-term performance. Accordingly, in this study we sought to determine the early and mid-term clinical and angiographic outcomes in a moderate-sized series of 86 consecutive patients who underwent placement of 108 premounted Duet stents in 98 coronary lesions. Procedural success, accomplished in all patients, was accompanied by a significant reduction in lesion severity from 89% +/- 11% before to 5% +/- 3% diameter stenosis after the procedure (P = 0.0001) and a 0.9% incidence of subacute stent thrombosis. Angiographic restudy at 5.7 months in 89% of eligible patients revealed a binary in-stent restenosis rate of 26%. Coronary stenting with the new Duet stent confers a low risk of stent thrombosis and a favorable mid-term clinical and angiographic outcome despite the presence of a large proportion of patients at high risk of in-stent restenosis.

Detection of a coronary arterial thrombus by indium-111-oxine-labeled platelet scintigraphy

Coronary arteriography revealed significant left anterior descending coronary artery stenosis in a 72-year-old man with a history of myocardial infarction. Stenting of the stenotic vessel was performed. Twelve hours after stenting the patient complained of chest pain but emergent coronary arteriography did not show sign of any coronary arterial stenosis. Under suspicion of coronary thrombus formation, indium-111-oxine-labeled platelet scintigraphy was performed 5 days after stenting, and revealed accumulation of indium-111-oxine in the area corresponding to the stent implantation site.

Ticlopidine versus oral anticoagulation for coronary stenting

BACKGROUND

A 2-4 week course of ticlopidine plus aspirin following coronary stenting is considered effective in preventing thrombotic occlusion of the stented vessel and safe in regards to bleeding and peripheral vascular complications. However, rare, although potentially life-threatening haematological complications have been reported with this drug regimen.

OBJECTIVES

To evaluate the efficacy and safety of ticlopidine plus aspirin versus oral anticoagulants after coronary stenting

SEARCH STRATEGY

Electronic search of the Cochrane Library, Medline, Embase from 1991 to June 1999; references from trials and experts.

SELECTION CRITERIA

Randomised controlled trials comparing ticlopidine plus aspirin versus oral anticoagulants (either with or without aspirin) after elective or bail out coronary stenting.

DATA COLLECTION AND ANALYSIS

Three reviewers assessed trial quality and compiled data on outcomes including: total mortality, non fatal myocardial infarction and revascularization occurring within the first 30 days after hospitalization, stent thrombosis on angiography, major and minor bleeding, neutropenia, thrombocytopenia, thrombotic thrombocytopenic purpura.

MAIN RESULTS

Four trials (n=2436 patients) were included. Ticlopidine plus aspirin compared to oral anticoagulants significantly reduced the risk of non-fatal acute myocardial infarction and revascularization at 30 days, combined negative events (mortality, myocardial infarction, revascularization at 30 days) (RR: 0.41; 95% CI: 0.25-0.69; NNT for 30 days: 22; 95% CI: 14-45), and major bleeding (RR in high quality studies: 0.24; 95% CI: 0.07-0.79). Ticlopidine plus aspirin compared to oral anticoagulants significantly increased the risk of eutropenia, thrombocytopenia and neutropenia (RR 5; 95% CI: 1.08-13.07; NNT for 30 days: 142; 95% CI: 76-1000). Ticlopidine plus aspirin vs oral anticoagulation did not affect all cause mortality. Ticlopidine plus aspirin significantly reduced the risk of stent thrombosis (angiography) which was seen only on studies with blinded outcome assessment (RR: 0.14; 95% CI: 0.03-0.60; NNT for 30 days: 33; 95% CI:16-166). Minor bleeding was reported only in one study and no studies recorded thrombotic thrombocytopenic purpura (TTP).

REVIEWER'S CONCLUSIONS

Ticlopidine plus aspirin after coronary stenting is effective in reducing the risk of the revascularization, non fatal myocardial infarction and bleeding complications when compared with oral anticoagulants. No effect is observed on total mortality. However, the haematological side effects of ticlopidine are still a matter of concern, and strict monitoring of blood-cell counts is recommended. Physicians should also be aware of the possibility of rare although potentially life-threatening complications such as TTP

A prospective evaluation of angiography-guided coronary stent implantation with high versus very high balloon inflation pressure

BACKGROUND

High inflation pressure (HP) after coronary stent deployment has become a standard approach because it has been associated with a decreased subacute stent thrombosis (SAT) rate. However, the impact of HP on long-term outcomes is still unclear. We compared the long-term results of a strategy of increasing HP (>/=12 atm) until the achievement of angiographic success (<20% residual stenosis) with a prespecified very high inflation pressure (VHP) strategy of 20 atm without intermediate inflations.

METHODS AND RESULTS

We conducted a parallel-group, nonrandomized study to evaluate the short- and long-term results in 136 consecutive eligible patients who underwent successful single Palmaz-Schatz stent implantation in vessels >/=3 mm. Major adverse cardiac events (MACE), that is, death, myocardial infarction, and target lesion revascularization (TLR), were monitored for a minimum of 6 months. No significant differences were observed between the two strategies in terms of final minimal lumen diameter (HP, 3.0 +/- 0.5 vs VHP, 3. 1 +/- 0.5 mm) and acute gain (HP, 2.1 +/- 0.7 vs VHP, 2.2 +/- 0.6). The overall rate of subacute stent thrombosis was 0.7%. During a 405 +/- 148-day follow-up, 21 (28.8%) patients in the VHP group and 6 (9. 5%) in the HP group (P =.005) had MACE, with a TLR rate of 27.4% versus 7.9% (P =.009), respectively. By multivariate analysis, the use of VHP increased the odds of long-term MACE by a factor of 3.48 (P =.009). Among patients undergoing TLR, those treated with VHP had a greater lumen loss (HP, 1.83 +/- 0.57 vs VHP, 2.15 +/- 0.36 mm, P =.02) and a more frequent pattern of diffuse restenosis (71% vs 16%, P =.06).

CONCLUSIONS

In our study, the two strategies had similar acute and short-term results, but VHP was associated with a poorer long-term outcome. These data provide a rationale for a less aggressive strategy for stent deployment by optimizing rather than attempting to maximize inflation pressure and stent expansion.

[Subacute thrombosis with antiplatelet treatment in a non-selected population of intracoronary stents: incidence and predictors]

INTRODUCTION

After coronary stenting, the incidence of subacute stent thrombosis have been reduced to 0% using aspirin and ticlopidine, in studies with selected populations and intracoronary ultrasounds.

OBJECTIVE

To evaluate the incidence and predictors of subacute stent thrombosis in a nonselected population, using antithrombotic therapy.

METHODS

We studied 285 stents, consecutively and successfully implanted in 268 lesions of 226 patients. We used high pressure balloon inflation without intracoronary ultrasound. Post-stenting protocol included aspirin and ticlopidine during four weeks with no anticoagulation. We defined subacute stent thrombosis as death, acute myocardial infarction myocardial infarction or angiographic occlusion of stent, with TIMI flow 0-1, after the first 24 hours and during the first month.

RESULTS

Four patients presented events (1.7%): Three nonfatal myocardial infarction after discharge, with documented angiographic thrombosis of stent, and one death due to in-hospital myocardial infarction. All three non-fatal AMI, occurred in vessels less than 3 mm (p = 0.07) and in patients taking aspirin without ticlopidine (p < 0.001). After discharge, three (17%) of 18 patients with inadvertent discontinuation of ticlopidine presented subacute stent thrombosis, in contrast to none of 25 patients taking ticlopidine without aspirin. Excluded patients with discontinuation of ticlopidine, the incidence of subacute stent thrombosis was 0.5%.

CONCLUSION

After intracoronary stenting in a nonselected population, using antithrombotic treatment with aspirin and ticlopidine, we may expect a rate of subacute stent thrombosis about 1%. Ticlopidine seems to have the main role in preventing subacute stent thrombosis, above all in predisposing circumstances as small vessels.

Angiographic and clinical outcome of a new self-expanding intracoronary stent (RADIUS): results from multicenter experience in Japan

The RADIUS coronary stent featuring a multisegmented slotted tube design and self-expanding nitinol delivery system has a high radial force and flexibility, uniform expansion, and contours to the shape of the vessel. Successful stent deployment was achieved in 104 stable angina patients (106 lesions; 44% LAD, 19% circumflex, and 37% RCA). Mean minimal lumen diameter (MLD) increased from 0.77 +/- 0.46 mm to 2.88 +/- 0.61 mm and mean percent diameter stenosis (% DS) decreased from 73 +/- 14% to 6 +/- 13% immediately after the procedure. At 6-month follow-up, two patients (2%) underwent urgent target revascularization, and cerebral bleeding occurred in one patient (1%). Angiographic follow-up was performed in 94 lesions (89%) and mean MLD and mean % DS were 2.08 +/- 0.92 mm and 30% +/- 24%, respectively. Stent restenosis (>50% diameter stenosis at follow-up) was observed in 16 (17%) of all lesions. The high success rate for stent deployment, low incidence of major adverse cardiac event, and lower restenosis rate after stent implantation indicate that the RADIUS stent is useful for coronary intervention.

Mid-term clinical and angiographic follow-up outcome after placement of a new balloon expandable stent in native coronary arteries

The widely disparate characteristics that exist among the different stent designs currently available for clinical use may impact on their acute and late angiographic and clinical results. The BeStent (Medtronic Instent, MN) is a relatively new stainless steel, laser-cut, serpentine stent design with only very limited data regarding its performance. In this report, we examined the results of 74 consecutive patients (54 men, 20 women; mean age, 58 years) treated with 76 BeStents in 75 native coronary arteries with a mean reference size of 2.8 mm. Successful stenting without 30-day major adverse cardiac complications was achieved in 97.3% of procedures, resulting in a significant improvement in diameter stenosis from 85% to 2% (P = 0.0001). Six-month angiographic restudy in 88% of patients revealed a per-lesion in-stent restenosis rate of 27%. At a mean follow-up period of 9.3 months, there were no deaths or myocardial infarctions. In summary, the present study demonstrates that the BeStent has an excellent performance profile, is associated with a low risk of stent thrombosis, and yields an acceptable restenosis rate despite the inclusion of a high proportion of patients with diabetes (41%) and small vessels (< 3.0 mm in diameter; 77%).

Biocompatibility of phosphorylcholine coated stents in normal porcine coronary arteries

OBJECTIVE

To improve the biocompatibility of stents using a phosphorylcholine coated stent as a form of biomimicry.

INTERVENTIONS

Implantation of phosphorylcholine coated (n = 20) and non-coated (n = 21) stents was performed in the coronary arteries of 25 pigs. The animals were killed after five days (n = 6), four weeks (n = 7), and 12 weeks (n = 8), and the vessels harvested for histology, scanning electron microscopy, and morphometry.

MAIN OUTCOME MEASURES

Stent performance was assessed by studying early endothelialization, neointima formation, and vessel wall reaction to the synthetic coating.

RESULTS

Stent thrombosis did not occur in either group. Morphometry showed no significant differences between the two study groups at any time point. At five days both the coated and non-coated stents were equally well endothelialised (91% v 92%, respectively). At four and 12 weeks there was no difference in intimal thickness between the coated and non-coated stents. Up to 12 weeks postimplant the phosphorylcholine coating was still discernible in the stent strut voids, and did not appear to elicit an adverse inflammatory response.

CONCLUSION

In this animal model the phosphorylcholine coating showed excellent blood and tissue compatibility, unlike a number of other polymers tested in a similar setting. Given that the coating was present up to 12 weeks postimplant with no adverse tissue reaction, it may be a potential candidate polymer for local drug delivery.

Intravascular ultrasonography in the evaluation of results of coronary angioplasty and stenting

The main advantage of intravascular ultrasonography (IVUS) over angiography in assessing the effect of coronary interventions is the ability of IVUS to directly visualize the vessel wall. IVUS often reveals a high residual plaque burden after angiographically successful angioplasty, and this can motivate the operator to use additional, more aggressive measures in an attempt to increase lumen dimensions. Studies using IVUS imaging before and after balloon angioplasty have shown that luminal gain after percutaneous transluminal coronary angioplasty (PTCA) results from a combination of plaque reduction and vessel wall stretch. Minimal luminal area and residual area stenosis after PTCA and stent deployment, as measured by IVUS, have been shown to be predictors of restenosis. IVUS studies have pointed to vessel shrinkage, not intimal hyperplasia, as the main mechanism of restenosis after PTCA. IVUS guidance of stent deployment has often revealed inadequate stent expansion despite optimal results on angiography, leading to high-pressure stent deployment with significant additional luminal gain. Restenosis rates may be lower with IVUS-guided stent deployment.

Short- and long-term outcomes of Wiktor stent implantation at low versus high pressures. Austrian Wiktor Stent Study Group

A prospective, randomized, multicenter trial was conducted to evaluate whether high-pressure postdilation of the Wiktor stent provides short- and long-term benefits compared with the conventional low-pressure implantation technique. From June 1995 through May 1996, 181 patients were randomly assigned to either low-pressure (6 to 12 atm, group A, n = 94) Wiktor stent placement or to high-pressure postdilation (> or = 13 atm, group B, n = 87) after stent deployment. All patients were followed up clinically for 7 +/- 3 months, with an angiographic follow-up in 154 patients (85%). After stent implantation, neither minimal lumen diameter (MLD) nor percent diameter stenosis (%DS) differed significantly between the 2 groups (MLD, 2.8 +/- 0.5 vs 2.9 +/- 0.5 mm; %DS, 17 +/- 8% vs 16 +/- 9% for groups A and B, respectively). However, a trend toward a larger mean lumen diameter within the stent was observed in group B (3.3 +/- 0.6 vs 3.5 +/- 0.5 mm for groups A and B, respectively; difference between means 0.14 mm, 95% confidence interval -0.01 to 0.29, p = 0.08). Angiographic follow-up revealed similar MLD and %DS in both treatment groups (MLD, 2.1 +/- 0.7 vs 2.2 +/- 0.8 mm; %DS, 31 +/- 17% vs 30 +/- 24% for groups A and B, respectively, p = NS). Acute stent thrombosis occurred in 2 patients (1%) (1 patient in each group), and subacute thrombosis in 1 patient (0.6%) in group A. There was 1 death in group A, and target lesion restenosis (> or = 50% DS) was observed in 15% of patients with no differences between the groups. In conclusion, this study demonstrated favorable short- and long-term results of Wiktor stent implantation. Despite a trend toward additional initial lumen gain by high-pressure postdilation, this did not translate into a measurable improvement in long-term outcome.

Immediate and mid-term results after MultiLink stent implantation in native coronary arteries

Different stent designs have widely disparate characteristics that may exert a positive or negative impact on their early and mid-term outcomes. The MultiLink stent (Guidant/Advanced Cardiovascular Systems, Santa Clara, CA) is a new coronary stent with only very limited data. In this report, we examined the results of 50 consecutive patients treated with 57 premounted sheathless MultiLink stents in 53 native coronary arteries with reference diameter > or =2.7 mm. Successful stenting was achieved in 98% of patients, resulting in an improvement in diameter stenosis from 91%+/-11% to 1%+/-3% (P = 0.0001). At 1 month, there was no death, myocardial infarction, or stent thrombosis. Angiographic restudy at a mean of 5.0+/-1.8 months in 94% of patients revealed an in-stent restenosis rate of 20.7%. The restenosis rates for diabetic patients (vs. nondiabetic patients), type C lesions (vs. type A/B1 lesions), and the use of 35-mm-long stents (vs. 15-mm-long stents) were 45.4% (14.3%), 56% (< or =11%), and 80% (8.8%), respectively (P < 0.05). In conclusion, the present study demonstrates that the MultiLink stent has an excellent performance profile, is associated with a low risk of stent thrombosis in native coronary vessels, and yields a favorable restenosis rate, particularly after the use of short (15 mm) stents to treat simple lesions.

Stent thrombosis: incidence and related factors in the R.I.S.E. Registry(Registro Impianto Stent Endocoronarico)

Although stent thrombosis has been greatly reduced by adequate stent expansion with high-pressure balloon inflations and by the use of antiplatelet drugs, this event is still frightening, as it may lead to acute myocardial ischemia resulting in acute myocardial infarction or sudden death. Therefore, the definition of factors associated with stent thrombosis may provide a better understanding of the mechanisms underlying this phenomenon and may permit us to define therapeutic strategies to further reduce its occurrence. The purpose of this study was to assess factors responsible for the occurrence of stent thrombosis after coronary stent implantation in 939 consecutive patients enrolled in the Registro Impianto Stent Endocoronarico (R.I.S.E. Study Group). Consecutive patients undergoing coronary stent implantation at 16 medical centers in Italy were prospectively enrolled in the registry. Clinical data, and qualitative and quantitative angiographic findings were obtained from data collected in case report forms at each investigator site. The study group consisted of 781 men and 158 women with a mean age of 59 yr: 1,392 stents were implanted in 1,006 lesions and expanded at a maximal inflation pressure of 14.7 +/- 3 atm. The great majority of patients (92%) received only antiplatelet drugs after coronary stenting. During hospitalization there were 45 major ischemic complications in 39 patients (4.2%): 13 events were related to acute or subacute thrombosis (1.4%). Another stent thrombotic event occurred in the first month of follow-up. On multivariate logistic regression analysis, stent thrombosis was related to the following factors: unplanned stenting (OR 3.46, 95% CI 1.65-7.23), unstable angina (OR 3.37, 95% CI 1.11-10.14) and maximal inflation pressure (OR 0.83, 95% CI 0.75-0.93). In conclusion, this registry shows that in an unselected population of patients undergoing coronary stenting, stent thrombosis occurs in less than 2% of patients and is significantly related to unplanned stent implantation, unstable angina, and maximal inflation pressure. The incidence of this phenomenon is likely to be further reduced by the use of new potent antiplatelet drugs, such as platelet glycoprotein IIb/IIIa antagonists.

Primary stenting of de novo lesions in small coronary arteries: a prospective, pilot study

Technical advancement and new anti-thrombotic regimens have recently shown so much improvement in the results of coronary stenting that the conventional contra-indication for stenting in small coronary arteries (<3 mm) needs to be revised. We undertook a prospective pilot study of elective Palmaz-Schatz stenting in de novo lesions located in coronary arteries of less than 3 mm diameter. Fifty consecutive patients (63 +/- 9 years) with stable (n = 38) and unstable angina (n = 12) were included. Philips-DCI quantitative coronary analysis was used to measure reference diameter, minimal lumen diameter and percent diameter stenosis before PTCA, after stenting and at 6-month angiographic follow-up study. All measurements were performed after intracoronary injection of nitroglycerin (300 microg). All patients received ticlopidine (250 mg/day) and aspirin (100 mg/day). The mean lesion length was 9 +/- 3 mm. The balloon size used for stent delivery was 2.75 mm in 30 patients and 2.5 mm in 20 patients and the mean balloon inflation pressure used for stent deployment was 12 +/- 2 atm. All stents were deployed successfully. In-hospital complications occurred in two patients, diagonal branch occlusion at day 2 requiring emergency PTCA in one and a hematoma at the femoral puncture site requiring surgery in the other. Major adverse cardiac event (MACE) rate remained 2% (nonfatal infarct in one). Follow-up angiography (n = 46, 92%) at 6 +/- 3 months showed a 30% restenosis rate. Target vessel revascularization (TVR) rate was 13%. We conclude that elective stenting in small coronary arteries is feasible and involves an acceptable risk of restenosis.

Coronary stenting in the elderly: longitudinal results in a wide spectrum of patients treated with a new and more practical approach

One hundred-twelve intracoronary stents (83 Palmaz-Schatz, 25 biliary, and 4 Gianturco-Roubin) were placed in 87 (51.7% male) patients aged > or = 70 years (70-93; mean 76.1) during a 1-year period. All stents were deployed using high-pressure inflation (mean 17.4 +/- 2 atm) without intravascular ultrasound. All patients received antiplatelet therapy with aspirin and ticlopidine. Seven patients additionally received warfarin at the physician's discretion. No patient was excluded from analysis regardless of presentation (40% acute myocardial infarction and 12.6% bailout) or complication. There were four deaths and two target vessel reinterventions in-hospital. One reintervention (a bailout) developed a non-Q-wave myocardial infarction. Bleeding, vascular complications, and length of stay were all greater for the warfarin group. The event-free survival rate was 83.9%, at an average of 8.6 months follow-up. A wide range of elderly patients can thus undergo stenting without intravascular ultrasound, usually without warfarin, yielding results comparable to those with more standard therapy in select populations.

Early experience with the NIR intracoronary stent

Immediate and midterm results of 61 NIR stent placement attempts in 55 native coronary vessels in 52 patients demonstrate a high clinical success rate of 98%, no early stent thrombosis, and a 5-month angiographic restenosis rate of 23%. The frequency of in-stent restenosis was significantly heightened in small vessel sizes and in diabetic patients.

Frequency of adverse clinical events in the 12 months following successful intracoronary stent placement in patients treated with aspirin and ticlopidine (without warfarin)

Little is known about the frequency of adverse events in the year following stent placement in patients treated with aspirin and ticlopidine, without warfarin. We analyzed the first such 234 consecutive patients treated at our hospital between October 1994 and December 1995. Their mean age was 62+/-12 years; 40% had had a prior myocardial infarction, 22% had undergone coronary artery bypass surgery, and 65% had multivessel disease. The indication for stent placement was dissection or abrupt closure in 24% of patients and suboptimal balloon angioplasty results in 14%; placement was elective in 62% of patients. Three hundred forty-five coronary segments were treated in the 234 patients; 305 stents (1.3 stents/patient) were placed. Palmaz-Schatz coronary stents (75%), Gianturco-Roubin stents (21%), and Johnson & Johnson biliary stents (4%) were used. Mean nominal stent size was 3.4+/-0.4 mm. High-pressure inflations (> or = 14 atm, mean 17+/-2) were performed in all patients. The mean residual stenosis was 3+/-5% by visual estimate. Intravascular ultrasound was utilized to facilitate stent placement in 53% of patients. Mean follow-up was 1.6+/-0.5 years. There were no deaths, Q-wave myocardial infarctions, coronary artery bypass operations, or repeat angioplasty procedures required during the remainder of the hospitalization or in 30 days after stent placement; stent thrombosis did not occur. Kaplan-Meier analysis of adverse events in the 6 months following the procedure revealed a mortality rate of 0.9%; the rate of myocardial infarction (Q-wave or non-Q-wave) was 1.3%. Bypass surgery was performed in 0.9% and angioplasty for in-stent restenosis was performed in 9.5% of patients. Any 1 of these events occurred in 11.7% of patients in the 6 months after the procedure. The corresponding event rates at 1 year were 1.3%, 2.2%, 3.5%, and 12.2%, respectively; any 1 of these events occurred in 16.5% of patients. In patients receiving intracoronary stents of varying designs followed by high-pressure postdeployment inflations in whom an excellent visual angiographic result is achieved, antithrombotic therapy with aspirin and ticlopidine is associated with a very low frequency of adverse cardiovascular events in the 12 months following the procedure regardless of the indication for stent placement.

Wiktor stent for treatment of chronic total coronary artery occlusions: short- and long-term clinical and angiographic results from a large multicenter experience

OBJECTIVES

This study reports the first multicenter experience with the Wiktor coil stent for treatment of chronic total coronary artery occlusions (CTOs).

BACKGROUND

Percutaneous transluminal coronary angioplasty (PTCA) of CTO is associated with very high restenosis and reocclusion rates. Coronary stenting has been proposed as a means of improving outcome. However, the Wiktor device for CTOs has never been tested in a large patient sample.

METHODS

From January 1993 to December 1996, 89 patients with 91 CTOs underwent Wiktor stent implantation after successful PTCA. The post-stenting regimen consisted of warfarin (Coumadin) plus aspirin in the initial 49 patients (55%) and aspirin plus ticlopidine in 40 patients (45%).

RESULTS

Stenting was successful in 87 patients (98%). At 1 month, 6% of patients had subacute stent thrombosis, 3% had a major bleeding event, and 1% had access-site complications. Subacute stent thrombosis showed univariate association with warfarin therapy (p = 0.009). Angiographic follow-up was obtained in 76 (93%) of 82 eligible patients. The restenosis rate was 32%, including 4% reocclusions. By multiple logistic regression analysis, restenosis was independently associated with multiple stents (adjusted odds ratio [OR] 27.67, 95% confidence interval [CI] 4.25 to 79.95, p = 0.0008) and increasing values of occlusion length (adjusted OR 1.23, 95% CI 1.09 to 1.39, p = 0.001). Freedom from death, myocardial infarction or stented vessel revascularization was 87% and 72% at 1 and 3 years, respectively.

CONCLUSIONS

Short- and long-term clinical and angiographic outcomes are favorable in patients undergoing Wiktor stent implantation in CTO. Further technical improvement is needed to reduce the restenosis rate in patients with long lesions and multiple stents.

Early and intermediate term clinical outcome after multiple coronary stenting

OBJECTIVE

To examine the immediate and intermediate term clinical outcome of multiple coronary stenting.

DESIGN

Consecutive patients were prospectively entered on a dedicated database. Follow up information was obtained from outpatient and telephone interviews with patients and family physicians.

SETTING

A tertiary referral centre.

PATIENTS

140 consecutive patients underwent multiple coronary stenting between April 1994 and November 1996. Most patients had unstable coronary syndromes.

MAIN OUTCOME MEASURES

Death, cerebrovascular accidents, myocardial infarction (MI), coronary artery bypass surgery (CABG), and repeat angioplasty (PTCA).

RESULTS

The angiographic success rate was 100% and the clinical procedural success rate 93%. The mean (SD) follow up was 11.9 (7.2) months (range 2-32). The mean (SD) number of stents per patient was 2.4 (0.7). The mean (SD) number of lesions treated per patient was 1.4 (0.6). There were four in-hospital deaths (2.9%) and five patients (3.6%) had an MI before hospital discharge. All in-hospital deaths occurred in patients presenting with an acute MI and cardiogenic shock. Three patients (2.2%) had a late MI. One patient with stent thrombosis underwent emergency CABG. Three patients (2.2%) underwent late CABG. Eight patients (5.7%) had a repeat PTCA. Eighty three patients (61.5%) were asymptomatic at follow up and 121 (86.4%) were free from major clinical events.

CONCLUSION

In an era of increased operator experience, high pressure stent deployment, and reduced anticoagulation with antiplatelet treatment alone, multiple coronary stenting may be performed with a high procedural success rate and good intermediate term outcome.

Coronary artery stenting without anticoagulation, aspirin, ultrasound guidance, or high balloon pressure: prospective study of 1,051 consecutive patients

Between March 1994 and November 1995, 1,212 coronary stents were implanted in 1,051 consecutive patients at our institution with the following protocol: daily pre- and poststenting treatment with ticlopidine 500 mg without aspirin, implantation under angiographic guidance, without ultrasound, with semi-compliant balloons inflated at 10 bars. Stenting was indicated after failure of balloon angioplasty (bail-out, dissection, elastic recoil) in 27% of the patients and considered as elective (de novo, restenosis, chronic occlusion, saphenous vein grafts) in 73% of the cases. During the 30-day follow-up period, stent thrombosis occurred in 11 patients (1.0%) and vascular access-site complications in three patients (0.3%). Thirteen patients (1.1%) died, 10 from previous left ventricular failure, 3 (0.3%) from subacute thrombosis. Multivariate analysis revealed that the size of the last balloon used was associated with subacute stent thrombosis Thus, in nonselected patients, placement of coronary stents may be safely achieved without use of warfarin, post procedural heparin, high balloon pressure, or ultrasound guidance. Antiplatelet therapy with ticlopidine and angiographic guidance result in a stent thrombosis rate of 1% and a vascular complication rate of 0.3%.

The use of the Gianturco-Roubin intracoronary stent: the New Approaches to Coronary Intervention (NACI) registry experience

The objective of this study is to compare the in-hospital and follow-up outcome in patients receiving the Gianturco-Roubin stent (GRS) who were enrolled in the New Approaches to Coronary Intervention (NACI) registry. The GRS was approved by the US Food and Drug Administration (FDA) in August 1992 for the treatment of acute or threatened closure after a percutaneous intervention. The application of intracoronary stenting has broadened substantially in the last few years, but less is known about the use of this device for other indications. Since the NACI registry includes patients stented for other indications, a comparison of these groups with patients being stented for acute or threatened closure was undertaken. A GRS was deployed in 497 NACI registry patients. Of these, 466 patients received a GRS in 1 of 3 of the following ways: (1) 351 unplanned stenting after conventional angioplasty of the same lesion; (2) 54 after failed/suboptimal use of a new device in the same lesion; and (3) 61 in planned stenting procedures. This analysis focuses on these 3 patient subgroups and compares their in-hospital outcome and subsequent follow-up to 1 year. There were 520 stented segments in the 466 patients. The group with stenting after failed/suboptimal new-device use had a higher incidence of myocardial infarction (MI) and cardiogenic shock than either the patients with unplanned stenting after percutaneous transluminal coronary angioplasty (PTCA) or planned stenting (MI 22.2% vs 12.0% vs 0%, respectively, and cardiogenic shock 5.6% vs 0.9% vs 0%, respectively; p < 0.05). This group also had significantly lower procedural success (58.7% vs 75.3% vs 81.5%, respectively; p < 0.05). Although not statistically significant, the requirement for transfusion was higher in the unplanned and new-device stented groups than in the planned group (10.5% vs 16.7% vs 1.6%, respectively). Likewise, the incidence of Q-wave MI was higher in the new-device group (22.2% vs 12% vs 0%, respectively; p < 0.05). Despite a higher, in-hospital complication rate in the unplanned groups, follow-up from discharge to 1 year showed similar outcome. In particular, percutaneous reintervention of the stented segment occurred in: 13.0% in the unplanned after new device; 17.4% in the unplanned after PTCA; and 26.2% in the planned group. Although not statistically significant, the higher incidence of percutaneous target lesion revascularization in the planned group probably represents the greater incidence of restenotic lesions in this cohort. In this very heterogeneous group of patients, including those with failure of another new device, the use of the GRS is associated with acceptable in-hospital and follow-up complication rates, although complications were clearly greater when unplanned use of the stent was needed, particularly after failure of another new device. Although the experience is small, patients having the GRS placed in an elective fashion, i.e., the planned group, appear to experience lower in-hospital complication rates, although they have a higher rate of subsequent target lesion revascularization, in this group of predominantly restenotic lesions.

Early versus late coronary stenting following acute myocardial infarction: results of the STENTIM I Study (French Registry of Stenting in Acute Myocardial Infarction)

This study was undertaken to determine the feasibility and safety of coronary stenting in acute myocardial infarction (AMI). In AMI, primary percutaneous transluminal coronary angioplasty (PTCA) is accepted as the preferred method of reperfusion for patients presenting at highly experienced centres. Until recently, however, stenting has been avoided during AMI because of a potential high risk of thrombosis. This prospective observational study carried out in 20 centres and included 648 consecutive patients who underwent PTCA with stent implantation for AMI. Of these 648 patients, 269 (41.5%, Group 1) were dilated early (< 24 hr) after the onset of the symptoms (75% treated by direct PTCA) and 379 (58.5%, Group 2) were dilated between 24 hr and 14 days after AMI. Combined therapy with ticlopidin and aspirin was used after the procedure. Bailout stenting occurred more often in Group 1 than in Group 2 (17% vs. 9.5%)(P < 0.05). Angiographic successful stenting was similar in both groups of patients (96% vs. 97%). During the hospital follow-up period, stent thrombosis occurred in eight patients (3%) in Group 1 and in six patients (1.6%) in Group 2 (NS). There was 14 deaths (5.2%) in Group 1 and 11 deaths (3.9%) in Group 2 (NS). After multivariate analysis bailout stenting was identified as the sole predictor of stent thrombosis (P < 0.0001). Vascular access-site complications occurred in six patients (1%) with no difference between the two groups. This study indicates that patients who receive a coronary stent in AMI can be managed safely with antiplatelet therapy. Randomized studies are needed to determine the precise indication for coronary stenting as an adjunct to primary PTCA.

Comparison of balloon angioplasty versus debulking devices versus stenting in right coronary ostial lesions

Angioplasty of aorto-ostial stenosis is associated with lower procedural success and a higher complication rate. The aim of the present study was to compare the acute and long-term results of balloon and new device angioplasty in 110 consecutive patients with right coronary ostial lesions. Patients were divided into 3 groups according to the angioplasty device used: group I (balloon only, n = 26), group II (debulking devices including excimer laser, directional and rotational atherectomy, n = 26), group III (stent, n = 58). Procedural success was highest in group III (96%) followed by group I (88%), and group II (77%). In-hospital complications were similar among the groups (p = NS). Patients in group III achieved the highest acute gain (2.61 mm) followed by groups II (1.92 mm), and I (1.39 mm, p <0.05). During follow up, target lesion revascularization and/or bypass surgery was required in 24% of patients in group III compared with 47% and 40% in groups I and II, respectively (p <0.05). Cardiac-event free survival was highest in the stent group (74%, p <0.005) and was similar between the balloon (39%) and debulking device groups (45%). Thus, among the currently available technologies, stenting of right coronary ostial lesions appears to provide excellent angiographic and long-term results.

Ultrasound-guided stent placement

IVUS imaging has dramatically increased understanding of the process of coronary stent placement. Preintervention or diagnostic IVUS has been shown to be of value before stent placement to assess lesion severity and length as well as the degree and location of calcification. Before stent placement, ultrasound dimensions may also be used to select the appropriate type and size of device. Although studies are in progress to define the role of prestent ultrasound imaging, much interest centers around the use of IVUS to detect significant superficial coronary calcium and direct rotational atherectomy before stent placement. Clinical trials have demonstrated the feasibility and safety of IVUS-guided coronary stent placement without postprocedure warfarin anticoagulation. Although it has been established subsequently that reduced anticoagulation may be administered to low-risk patients without IVUS guidance, three important points have been established by these trials. First, IVUS is superior to angiography for assessment of adequate stent expansion and apposition. As noted in several studies, angiography frequently overestimates lumen dimensions after stent placement. Second, IVUS-guided stent implantation yields larger acute stent dimensions. Third, IVUS-guided therapy in the form of additional stent placement or use of a larger balloon does not increase stent procedure complication rates when appropriate criteria for optimal stent placement are used. A randomized clinical trial (AVID) of angiography-directed versus IVUS-directed coronary stent placement is in progress (with a second soon to begin enrollment). In this trial, ultrasound guidance has been shown to improve acute procedural results, providing larger lumen dimensions without an increase in complication rates. IVUS guidance, however does not appear to affect the incidence of stent thrombosis within 30 days in the present era of high-pressure balloon inflations and aggressive antiplatelet therapy. Results concerning the effect of ultrasound-guided therapy on long-term target lesion revascularization rates are pending. To date, IVUS imaging has greatly contributed to advancements in coronary stent placement techniques. The future of IVUS-guided coronary stent placement will, of course, depend on the results of several ongoing clinical trials.

Intracoronary stenting using slotted tubular stents with intravascular ultrasound and anticoagulation

Intravascular ultrasound guidance has been suggested as a prerequisite before managing patients receiving slotted tubular stents without anticoagulation. The purpose of this prospective observational study was to determine if patients receiving this stent can be similarly managed following angiographic guided stent deployment without intravascular ultrasound assistance. A total of 137 patients receiving slotted tubular stents were selected to receive a protocol of aspirin 325 mg and ticlopidine 250 mg for 30 days following the satisfaction of certain angiographic criteria. These criteria were: adequate coverage of intimal dissections, absence of residual filling defects, and normal (TIMI III) flow in the stented vessel at the end of the procedure. The stenting procedure was planned in 68% of patients and unplanned in 32% of patients. During the 30 day clinical follow period there were no stent thrombosis events, no Q-wave myocardial infarctions, and no deaths. Non-Q-wave myocardial infarction occurred in 3 patients (2.2%), hemorrhage requiring blood transfusion in 3 patients (2.2%), and 1 patient (0.7%) developed a pseudo-aneurysm of the cannulated femoral artery. These data indicate that patients receiving slotted tubular stents with optimal angiographic results can be safely managed with the combination of aspirin and ticlopidine without anticoagulation or the need for intravascular ultrasound guidance.

Comparison of aspirin alone versus aspirin plus ticlopidine after coronary artery stenting

This prospective nonrandomized study was performed comparing aspirin alone (n = 46) versus aspirin and ticlopidine (p = 338) following native coronary artery stenting. There were significantly more stent thrombosis events in the aspirin-only group than in the aspirin and ticlopidine group (6.5% vs 0.9%, p = 0.02) and significantly more Q-wave myocardial infarctions and cardiac-related deaths in the aspirin-only group than in the aspirin and ticlopidine group (6.5% vs 0%, p = 0.002 and 4.4% vs 0.3% p = 0.02, respectively).

Placement of multiple and different stent types for very long dissections during coronary angioplasty

We have been investigating the safety and efficacy of multiple and different stent types placed in the unfavorable situation of a very long dissection (> 20 mm) after coronary angioplasty. We report our preliminary experience in 20 patients who were treated by the following combinations: Palmaz-Schatz and Micro stent (14 patients). Wallstent and Micro stent (4 patients); Wiktor and Micro stent (1 patient); and Palmaz-Schatz, Micro and Wallstent (1 patient). Normal distal flow was restored in all except one (no reflow phenomenon) patient and complete covering of the dissection was obtained in all but two patients. Event-free survival at 30 days was 90% (18 of 20 patients). During follow-up (mean period: 8 +/- 3 months), two patients died. Of the 18 other patients, 16 remained asymptomatic and free of complications. Symptomatic restenosis was treated by standard angioplasty in the two remaining patients. In conclusion, placement of different stent types seems a feasible, safe, and efficient treatment for very long dissections caused by standard angioplasty.

A cost analysis of coronary stenting without anticoagulation versus stenting with anticoagulation using warfarin

A case-controlled study was performed comparing hospitalization costs and length of hospital stay in a group of patients managed with antiplatelet therapy only, versus a group treated with anticoagulation using warfarin after coronary artery stenting. The patients managed with antiplatelet therapy alone had significantly reduced total hospitalization costs and a significantly reduced average hospital stay than patients managed with anticoagulation.