Predictors of thrombotic complications after placement of the flexible coil stent

Long-term serial changes in platelet activation indices following sirolimus elution and bare metal stent implantation in patients with stable coronary artery disease

BACKGROUND

Platelet activation is crucial in the development of stent thrombosis following percutaneous coronary intervention (PCI). We carried out a long-term assessment of multiple factors implicated in the thrombotic process and monitored markers of platelet activation after the implantation of sirolimus-eluting stents (SES) in patients with stable coronary artery disease (CAD). Additionally, we compared these findings with those after bare-metal stent (BMS) implantation.

METHODS

A cohort of 47 consecutive patients, aged <70 years, with severe stenosis (>70% narrowing of the lumen) of one major epicardial coronary artery and stable CAD underwent successful elective PCI. Patients were randomly allocated to SES (n = 25) or BMS (n = 22). Venous blood was obtained 24 hours before and 24 hours, 48 hours, 1 month, and 6 months after PCI for measurements of plasma levels of sP-selectin, von Willebrand Factor (vWF), fibrinogen, d-dimer, sCD40, factor VIII, b-thromboglobulin (b-TG) and platelet factor 4 (PF-4).

RESULTS

There were no significant differences between the two groups in levels of fibrinogen or d-dimers in peripheral blood. However, we observed a significant kinetic effect (p<0.001) and stent-effect (p<0.015) on vWF levels and a significant kinetic effect (p = 0.012) on factor VIII, sP-selectin (p = 0.04), b-TG (p<0.001), and PF4 (p = 0.016). A trend towards a significant stent effect on sCD40 was also detected (p = 0.06).

CONCLUSIONS

SES and BMS did not show significant differences in relationship to markers of platelet activation and coagulation in patients with stable CAD. Although some markers showed an increase after stent implantation, they returned to the initial levels 6 months later.

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.

The impact of gender on vessel size in patients with angiographically normal coronary arteries

INTRODUCTION

Female gender has been associated with worse clinical outcomes following coronary revascularization. Whether a gender-specific difference in vessel size is contributing to this finding remains controversial. We sought to better define the relationship between gender and coronary artery size.

METHODS

Baseline characteristics were obtained and quantitative coronary angiography was performed on 145 consecutive patients with angiographically normal (smooth luminal surface with no evidence of any irregularity in the coronary tree) coronary arteries. Two separate orthogonal measurements each were taken of the left main, proximal left anterior descending, proximal circumflex, proximal right coronary artery, and ostial posterior descending arteries. An average coronary size, derived from five separate coronary artery measurements, was tabulated for each patient.

RESULTS

After correcting for confounding variables, including BSA, height, diabetes, and left ventricular hypertrophy using multivariate linear regression, female gender remained a strong independent predictor of coronary vessel size (Beta =-0.30, P = 0.004). Female gender was associated with a 0.30 mm decrease in average coronary size.

CONCLUSION

Gender is a strong, independent predictor of coronary artery size even when taking into account differences in body size. This difference may contribute to worse outcomes of women undergoing coronary revascularization.

New approaches to long lesions

Long coronary lesions, comprising up to 20% of the interventional practice, pose a significant challenge to the interventionalist. Several approaches have been described to treat long coronary lesions with long-term suboptimal outcomes. Atherectomy and laser treatments with or without adjunctive balloon angioplasty have not been shown to be superior to conventional balloon angioplasty alone. Preliminary data with the use of drug-eluting stents in the treatment of long coronary lesions appears to be promising even in small vessels and may eventually become the mainstay treatment of long lesions.

Intracoronary brachytherapy with ??-radiation for the treatment of long diffuse in-stent restenosis

OBJECTIVE

To assess the efficacy of intracoronary brachytherapy with beta-radiation (Sr/Y) for the treatment of long diffuse in-stent restenosis (ISR).

METHODS

As recurrent ISR depends on intimal injury after coronary angioplasty, long in-stent restenotic lesions were defined as lesions with a treatment length >26 mm (lesion length >20 mm plus a treatment margin of 3 mm at each end). Seventy-eight patients with long ISR were treated at our institution with beta-brachytherapy after coronary angioplasty. Patients were irradiated with either an approximate dose of 12 Gy at 1 mm vessel wall depth or with 18 Gy at 1 mm vessel wall depth. Clinical follow-up was available for 69 patients and angiographic follow-up for 65 patients. Late lumen loss (LLL), binary restenosis (stenosis >50%), target lesion revascularization (TLR) and major adverse cardiac events (MACE) were assessed for a follow-up time of 6.6+/-2.2 months.

RESULTS

Mean interventional treatment length was 46+/-18 mm. TLR was performed in all 23 patients with binary restenosis (33%). Death of cardiac cause was reported for two patients, one of whom did not undergo TLR. Thus, overall MACE rate was 35%. Recurrent ISR was significantly more frequent in patients with geographic miss. Comparison of the different radiation dose regimens revealed significantly lower LLL in patients irradiated with the higher dose (0.20+/-0.68 mm compared with 0.65+/-0.96 mm, P=0.03).

CONCLUSION

Intracoronary brachytherapy with beta-radiation (Sr/Y) is a safe and effective therapeutic option for the reduction of recurrent ISR in long diffuse lesions. We recommend a high-dose irradiation with 18 Gy at 1 mm vessel wall depth.

Clinical impact of stent construction and design in percutaneous coronary intervention

Convincing end point data demonstrating the anatomic and clinical superiority of stent placement compared with balloon angioplasty together with significant improvement in stenting technique and poststent management have resulted in an explosion in stenting procedures and the emergence of more than 40 stent types with disparate designs and material composition in clinical use. Structural nuances in design, composition, and coating of different stent models, however, have been shown to have a major influence on the risk of stent thrombosis, the degree of vessel wall injury, and subsequent intimal proliferation in the experimental model. There is now substantial amount of evidence to indicate that the same relationship between stent structural characteristics and vessel wall outcome holds true in humans. This article provides an up-to-date overview of the clinical impact of stent construction and design, including the clinical performance of drug-eluting stents.

Early and late outcome of stenting in a consecutive series of patients with coronary lesions in vessels less than 2.8 mm in diameter

In an attempt to determine the early and late outcomes of small vessel stenting, we retrospectively evaluated our database on 51 consecutive patients (41 males, mean age, 57.1 +/- 10.1 years) who underwent stenting of at least one significant lesion in a coronary artery with a reference vessel diameter (RVD) <2.8 mm between March 1999 and March 2001. Sixty balloon expandable tubular stents were implanted in 57 lesions (29 Type B2/C, mean RVD: 2.54 +/- 0.16 mm) without intravascular ultrasound guidance under a heparin-aspirin-ticlopidine regimen. The mean diameter stenosis (DS) decreased from 75.8 +/- 13.6% to 4.2 +/- 1.9% (P<0.0001) with stenting at a mean deployment pressure of 13.6 +/- 1.7 atm and a final balloon to RVD ratio (FB/RVD) of 1.08 +/- 0.03. All stents were deployed successfully. Acute stent thrombosis occurred in 3 patients (6%), one died, and 2 developed non-Q-wave myocardial infarction (procedural success 94%). Clinical follow-up, available in 48 patients, revealed a 29% target lesion revascularization rate, a 2% myocardial infarction rate, and a 71% event-free survival at a mean of 11.6 months. Angiographic follow-up, available in 40 patients, showed a DS of 48.8 +/- 31.3% and a binary restenosis rate of 50% at a mean of 7.7 months. The FB/RVD ratio was significantly lower in the group with restenosis than in the group without (1.06 +/- 0.02 vs 1.1 +/- 0.05, P = 0.04). Subgroup analysis yielded a significantly greater rate of restenosis in diabetics with complex (Type B2/C) lesion morphology compared to nondiabetics with simple (Type A/B1) lesions (75% vs 21%, P < 0.05). In conclusion, stenting in vessels <2.8 mm was found to be associated with a high rate of acute stent thrombosis and in-stent restenosis. Further analysis detected a subgroup of patients without diabetes or complex lesions who could be stented with an acceptable in-stent restenosis rate.

Influence of stent treatment strategies in the long-term outcome of patients with long diffuse coronary lesions

Diffuse coronary lesions (length > 20 mm) are still considered high risk for percutaneous intervention even in the current stent era. We compared the 2-year outcome of patients with long diffuse stenosis treated by three different stent strategies. In addition, we also analyzed the possible factors influencing a favorable late outcome. Our series is constituted by 232 patients with 247 long lesions treated between May 1994 and April 1999; 82 patients received one single long stent (group 1), 71 patients were treated by overlapped multiple stents (group 2), and 79 with multiple nonoverlapped stents (group 3). The mean age was 59 +/- 11 years. There were not significant differences between groups in terms of age, risk factors, clinical presentation, type of lesion, or adjunctive medical therapy. Patients from group 1 had shorter lesions (29 +/- 10 mm) than patients from groups 2 (41 +/- 15 mm) and 3 (36 +/- 14; P < 0.05). Major cardiac events (death, acute myocardial infarction, or repeat revascularization) at 24 +/- 12 months follow-up took place in 39 patients (17%). The probabilities of being free of major events at follow-up were 71%, 78%, and 80% for group 1, 2, and 3 respectively (P = NS). Only three variables were identified as significant predictors of these late events: smaller vessel size, smaller minimal lumen diameter after stenting, and the type of lesion being restenotic as compared with native stenosis. Patients with diffuse lesions treated by single long stents did not have a better late outcome than those who received multiple stents. The best late outcome was observed in those patients who had bigger vessel size, larger poststent lumen dimensions and native lesions, regardless of the stent deployment strategy used.

The elective use of the seven-cell NIR stent in coronary arteries < 2.75 mm in diameter: clinical and angiographic results at 6-month follow-up

The outcome of interventional procedures has been improved by the use of coronary stents in vessels > 3.0 mm in diameter. We report a single-center prospective study of elective coronary stenting in 39 consecutive patients with de novo lesions and reference diameters < 2.75 mm. Seven-cell NIR stents were deployed with standard antiplatelet therapy, but without routine use of IIb/IIIa inhibitors or intravascular ultrasound. There was one case of acute stent thrombosis, but no cases of subacute thrombosis. The binary restenosis rate was 27.8% (10/36 lesions) and the target lesion revascularization rate was 19.4%. Symptoms improved markedly as judged by Canadian Cardiovascular Society and questionnaire scores and the use of antianginal therapy. This pilot study suggests that the elective use of coronary stents in vessels < 2.75 mm in diameter is safe with acceptable long-term results. A randomized trial comparing outcomes after stents and balloon angioplasty in small vessels is required.

Comparison of immediate and one-year outcome after coronary angioplasty of narrowing < 3 mm with those > or =3 mm ( the National Heart, Lung, and Blood Institute Dynamic Registry)

Balloon angioplasty of small coronary artery lesions has been associated with lower success and higher complication rates than large coronary artery lesions. This study evaluates the in-hospital and 1-year outcome of the treatment of small coronary artery lesions in the modern era of interventional cardiology and compares it with the outcome of treating large coronary artery lesions. Of 1,658 patients with a single lesion treated from July 1997 to February 1998 in the National Heart, Lung, and Blood Institute (NHLBI) Dynamic Registry, there were 587 patients with small coronary artery lesions (<3 mm) and 1,071 patients with large coronary artery lesions (> or =3 mm). Success, in-hospital, and 1-year outcomes between both groups were compared. Patients with lesions in small coronary arteries were more often women, insulin-treated diabetics, and had undergone more prior coronary bypass graft surgery. Conventional angioplasty alone was performed more often and angioplasty with stents was performed less often in the small coronary artery than in the large coronary artery group. Angiographic success was slightly lower in the small coronary artery group (94.2% vs 96.9%, p <0.05). Periprocedural and in-hospital complication rates were similar in both groups. Likewise, at 1-year follow-up, major adverse cardiac events including death, myocardial infarction, and coronary artery bypass graft surgery were relatively low and comparable between the 2 groups, although patients with small coronary arteries were more likely to undergo repeat revascularization (17.4% vs 13.6%, p <0.05). Treatment of lesions in small coronary arteries in the modern era is associated with high success and low complication rates, comparable to the treatment of large coronary artery lesions, although the incidence of repeat revascularization was significantly greater at follow-up even if stents were used.

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.

Immediate and one-year outcome of intracoronary stent implantation in small coronary arteries with 2.5-mm stents

BACKGROUND

The role of coronary stenting in the treatment of stenoses in small coronary arteries with use of 2.5-mm stents is not well defined.

METHODS AND RESULTS

Between January 1995 and August 1999, 651 patients with stenoses in small coronary arteries were treated with 2.5-mm stents (n = 108) or 2.5-mm conventional balloon angioplasty (BA) (n = 543). Patients who received treatment with both 2.5-mm and > or =3.0-mm stent placement or balloons were excluded. Procedural success and complication rates as well as 1-year follow-up outcomes were examined. Baseline clinical characteristics were similar between the two groups, except patients in the stent group were more likely to have hypertension and a family history of coronary artery disease and less likely to have prior myocardial infarction. Angiographic success rates were higher in the stent group (97.2% vs 90.2%, P =.02). In-hospital complication rates were comparable between the two groups. Among successfully treated patients, 1-year follow-up revealed no significant differences in the survival (96.2% vs 95.2%, P =.89) or the frequency of Q-wave myocardial infarction (0% vs 0.4%, P =.60) or coronary artery bypass grafting (8.4% vs 6.8%, P =.89) between the stent and BA groups, respectively. However, patients in the stent group were more likely to have adverse cardiac events (35.4% vs 22.1%, P =.05). Stent use after excluding GR II stent use, however, was not independently associated with reduced cardiac events at follow-up (relative risk 1. 3 [95% confidence interval 0.8-2.3], P =.30).

CONCLUSIONS

Intracoronary stent implantation of stenoses in small coronary arteries with 2.5-mm stents can be carried out with high success and acceptable complication rates. However, compared with BA alone, stent use was not associated with improved outcome through 1 year of follow-up.

[Intracoronary stents in small vessels: short- and long-term clinical results]

OBJECTIVE

To assess the clinical outcome of coronary stenting in small vessels (< 3 mm), using high pressure balloon inflation and antithrombotic therapy.

PATIENTS AND METHODS

Vessel size was evaluated as < or >= 3 mm at the time of procedure and measured at a level of maximum diameter. We studied 234 consecutive patients with placement of 300 stents in 279 lesions, comprising 84 stents implanted in 79 lesions located at small vessels (< 3 mm). The standard technique included high pressure balloon inflation (15.8 +/- 2.2 atm) and post-stenting therapy with ticlopidine and aspirin for one month. Mean clinical follow-up was 17.6 +/- 10 months.

RESULTS

Procedural success without in-hospital major events was similar between small and large vessels (93.7 in vessels of < 3 mm vs 93.5% in vessels of >= 3 mm; p = NS). Three small vessels presented subacute stent thrombosis, whereas no thrombotic occlusion occurred in large vessels (3.8 vs 0%; p = 0.006). At two years, small vessels had a lower target lesion revascularization free survival (73.6 vs 90.3%; p < 0.001). After adjustment for variables previously described as predictors of stent restenosis, in multivariate analysis, a small vessel of < 3 mm was an independent predictor of target lesion revascularization (p = 0.001). Although patients with stenting in small vessels did not differ significantly in terms of any cause death (4.6 vs 3.8%; p = 0.7) nor acute myocardial infarction (2.9 vs 1.1%; p = 0.3), event-free survival was significantly lower after two years (69.1 vs 86.6%; p < 0.001).

CONCLUSIONS

As compared to large vessels, coronary stenting in small vessels was performed with similar rates of initial success, however they had a significantly worse clinical long-term outcome in terms of subacute stent thrombosis and target lesion revascularization at follow-up.

A comparison of systematic stenting and conventional balloon angioplasty during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction. STENTIM-2 Investigators

OBJECTIVES

In a multicenter, randomized trial, systematic stenting using the Wiktor stent was compared to conventional balloon angioplasty with provisional stenting for the treatment of acute myocardial infarction (AMI).

BACKGROUND

Primary angioplasty in AMI is limited by in-hospital recurrent ischemia and a high restenosis rate.

METHODS

A total of 211 patients with AMI <12 h from symptom onset, with an occluded native coronary artery, were randomly assigned to systematic stenting (n = 101) or balloon angioplasty (n = 110). The primary end point was the binary six-month restenosis rate determined by core laboratory quantitative angiographic analysis.

RESULTS

Angiographic success (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3 and residual diameter stenosis <50%) was achieved in 86% of the patients in the stent group and in 82.7% of those in the balloon angioplasty group (p = 0.5). Compared with the 3% cross-over in the stent group, cross-over to stenting was required in 36.4% of patients in the balloon angioplasty group (p = 0.0001). Six-month binary restenosis (> or = 50% residual stenosis) rates were 25.3% in the stent group and 39.6% in the balloon angioplasty group (p = 0.04). At six months, the event-free survival rates were 81.2% in the stent group and 72.7% in the balloon angioplasty group (p = 0.14), and the repeat revascularization rates were 16.8% and 26.4%, respectively (p = 0.1). At one year, the event-free survival rates were 80.2% in the stent group and 71.8% in the balloon angioplasty group (p = 0.16), and the repeat revascularization rates were 17.8% and 28.2%, respectively (p = 0.1).

CONCLUSIONS

In the setting of primary angioplasty for AMI, as compared with a strategy of conventional balloon angioplasty, systematic stenting using the Wiktor stent results in lower rates of angiographic restenosis.

[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.

Clinical and angiographic outcome after angiography-guided stent placement in small coronary vessels

BACKGROUND

Although it is widely accepted that stenting confers favorable angiographic and clinical results in coronary arteries >/=3.0 mm in diameter, the outcome of stent placement in smaller vessels remains largely unclear.

METHODS AND RESULTS

We sought to specifically determine the early and long-term clinical outcomes in a large series of 197 consecutive patients who underwent stent placement in 207 vessels <3.0 mm in diameter. Procedural success, accomplished in 97.3%, was accompanied by a significant reduction in lesion severity from 85% +/- 9% before to 3% +/- 7% diameter stenosis after the procedure (P =.0001) and a 0.5% incidence of subacute stent thrombosis. At 1 and 2 years of follow-up, survival rate without major target lesion-driven events was observed in 77.3% and 73.9% of patients, respectively. Repeat revascularization procedures accounted for most of these events; cardiac deaths (including those related to subacute stent thrombosis) and late (>30 days) myocardial infarctions were infrequent (2.4% and 1.0%, respectively). The 6-month angiographic binary instent restenosis rate was 30.1%. On multivariate analysis, diabetes mellitus (P =. 0275), small baseline reference vessel size (P =.0300), and stent size </=2.7 mm (P =.0111) were independently associated with an increased instent restenosis rate.

CONCLUSIONS

Optimal angiography-guided coronary stenting of vessels <3.0 mm in diameter in association with the stringent use of a poststent combined aspirin-ticlopidine antiplatelet regimen confers a low risk of stent thrombosis, an acceptable incidence of angiographic instent restenosis, and a favorable long-term clinical outcome.

Triage of patients for short term observation after elective coronary angioplasty

OBJECTIVE

To evaluate triage of patients for short term observation after elective percutaneous transluminal coronary angioplasty (PTCA), as appropriate selection of patients for short term observation after angioplasty may facilitate early discharge.

METHODS

1015 consecutive patients scheduled for elective PTCA were prospectively included for short term observation. Patients with unstable angina Braunwald class III were excluded. There were no angiographic exclusion criteria. Patients were discharged from the interventional centre when considered stable during 4 hours of observation after PTCA. It was left to the operator's discretion whether to prolong the observation period. Procedural complications were defined as death, coronary bypass surgery, early repeat PTCA, and myocardial infarction.

OUTCOME MEASURES

The need for prolonged observation (> 4 hours) and the occurrence of complications. Predictors for prolonged observation and the occurrence of complications after the 4 hours observation were assessed by univariate and multivariate analysis.

RESULTS

Two patients died, including one of six patients who underwent emergency bypass surgery. In all, 922 patients (90.8%) were triaged to short term observation and had an uncomplicated three day follow up. Observation was prolonged in 87 patients (8.6%), and 40 patients had a complicated course. Independent predictors of procedural complications were acute closure (odds ratio (OR) 9.7; 95% confidence interval 4.4 to 21.4), side branch occlusion (OR 8.9; 3.4 to 23.7), no angiographic success (OR 5.1; 2.4 to 11.0), female sex (OR 3.1, 1.7 to 5.7), any unplanned stent (OR 2.8, 1.4 to 5.9), and ostial lesion (OR 2.2, 1.0 to 4.7).

CONCLUSIONS

A 4 hour observation period is safe after elective coronary angioplasty. As procedural variables are the strongest predictors of postprocedural complications, the immediate procedural results allow effective triage of patients for short term or prolonged observation in order to anticipate complications.

Long-term follow-up of primary stenting with coil stent in acute myocardial infarction

The authors evaluated clinical and angiographic outcomes for 1 year after primary stenting using coil stent for acute myocardial infarction. Twenty-eight patients underwent primary stenting with coil stent. Follow-up coronary arteriography at 3 months and 1 year was planned in all patients. Procedural success was achieved in 96%. There was no acute or subacute thrombosis. Minimal lumen diameter (MLD) was increased from 0.08 +/- 0.19 to 2.73 +/- 0.49 mm after stenting. MLD had decreased significantly for 3 months (MLD at 3 months: 2.03 +/- 0.86 mm, p = 0.001). On the other hand, MLD did not differ between 3-month; and 1-year follow-up (MLD at 1 year: 2.26 +/- 0.73 mm, p = NS). Only one patient manifested reocclusion at 3-month follow-up. The cumulative restenosis rate and target lesion revascularization rate at 1-year follow-up were 25.9% (7/27) and 11.1% (3/27). Primary stenting using coil stent is safe and feasible in patients with acute myocardial infarction and may improve clinical outcome and decrease restenosis and target lesion revascularization rate.

Acute and late outcome after use of 2.5-mm intracoronary stents in small (< 2.5 mm) coronary arteries

We describe the high-pressure deployment of 2.5-mm stents in small (< 2.5 mm) coronary vessels. Forty-three lesions in 40 patients were treated. The mean reference vessel diameter was 2.3 +/- 0.2 mm. The mean % luminal stenosis was 90 +/- 9. The mean lesion length was 11. 7 +/- 9.1 mm. Sixteen lesions were pretreated with rotational atherectomy, and the remainder with PTCA. The rate of successful stent deployment was 41/43 (95%). The mean postintervention % stenosis was -1 +/- 10. There were no in-hospital deaths or procedure-related Q-wave MI. The patients were followed for a mean of 18 months. Eight patients (or 21%) developed recurrent chest pain and/or angiographically proven restenosis. One patient (3%) developed intermediate restenosis. Twenty-nine patients (or 76%) either remain symptom-free or have patent target sites on repeat angiography. It appears that reasonable acute and long-term results can be achieved with 2.5-mm stents in small coronary arteries using high-pressure deployment techniques. Cathet. Cardiovasc. Intervent. 49:121-126, 2000.

[Results of coronary stenting in acute myocardial infarction]

OBJECTIVE

To describe the angiographic results and the in-hospital clinical outcome of patients with an acute phase of myocardial infarction treated with coronary angioplasty and stent placement.

METHODS

268 patients with myocardial infarction were treated with angioplasty and coronary stenting within in our center 12 hours after the onset of symptoms from January in 1992 to March 1998. 366 stents were placed (1.4 +/- 0.7 per patient), 35% being Palmaz-Schatz, 26% Wiktor, 21% Multi-Link and 18% others. Stenting was elective in 171 patients (64%), and the majority of patients (91%) were treated with aspirin plus ticlopidine.

RESULTS

A successful angiographic result was achieved in 258 patients (96%). Minimum lumen diameter was increased from 0.2 +/- 0.3 to 2.7 +/- 0.7 mm (p < 0.001), and stenosis decreased from 94 +/- 8% to 13 +/- 11% (p < 0.001). Mortality was 15.3% (3.2%, 24.4% and 67.7% in patients in Killip class I, II-III and IV, respectively). Nonfatal reinfarction and recurrent ischemia rates were 2.6% and 9%, respectively. Stent thrombosis occurred in 8 patients (3.0%), and new target vessel revascularization was needed in 12 (4.5%).

CONCLUSIONS

Stent placement in acute myocardial infarction is associated with high angiographic success rate, as well as a good in-hospital outcome. Mortality is localized, especially in patients with cardiac failure at the beginning of the procedure.

Primary stent implantation is superior to balloon angioplasty in acute myocardial infarction: final results of the primary angioplasty versus stent implantation in acute myocardial infarction (PASTA) trial. PASTA Trial Investigators

Several studies have shown that stent implantations in acute myocardial infarction (AMI) result in better short- and long-term outcomes than primary balloon angioplasty. These results, however, have not been ascertained in randomized trials. We randomized 136 patients out of 208 patients with AMI within 12 hr from onset into two groups: 69 patients with primary balloon angioplasty (POBA group) and 67 patients with primary stent implantation (STENT group). We compared the incidences of major cardiac events (repeat MI, target lesion revascularization, and cardiac death) and angiographic parameters during hospitalization and follow-up periods up to 12 months in these two groups. There was no significant difference in the reperfusion success rates. The incidences of major cardiac events were lower in the STENT group than in the POBA group during hospitalization, the first 6 months and 12 months (6% vs. 19%, P = 0.023; 21% vs. 46%, P < 0.0001; 22% vs. 49%, P = 0.0011). Minimum lumen diameters were significantly bigger in the STENT group than the POBA group at predischarge angiogram and 6-month follow-up (2.85 +/- 0.62 vs. 2.08 +/- 0.82 mm, P < 0.0001; 2.24 +/- 0.64 vs. 1.72 +/- 0.76, P = 0.002). Restenosis rates at 6-month follow-up were significantly lower in the STENT group than in the POBA group (17% vs. 37.5%, P = 0.02). In selected patients with AMI, primary stent implantation results in a lower incidence of major cardiac events during the first 12 months, postprocedure, and less frequent 6-month restenosis than primary balloon angioplasty.

The role of coronary angioplasty and stenting in acute myocardial infarction

Despite the improvements in the pharmacological treatment of acute myocardial infarction, it is recognised that thrombolysis fails to reproduce reperfusion in a significant proportion of patients. Coronary interventional techniques have been shown to offer an alternative reperfusion strategy. There is increasing evidence that mechanical reperfusion may offer significant advantages over established thrombolytic therapy.

Stented segment length as an independent predictor of restenosis

OBJECTIVES

We sought to evaluate the relation between stented segment length and restenosis.

BACKGROUND

Multiple or long coronary stents are now being implanted in long lesions or in tandem lesions. A longer stented segment might result in a higher probability of restenosis. However, there is little information available on the relation between stented segment length and restenosis.

METHODS

Between April 1995 and December 1996, 725 patients with 1,090 lesions underwent stenting. Lesions were divided into three groups according to the length of the stented segment: 1) group I (n = 565): stented segment length < or =20 mm; 2) group II (n = 278): stented segment length >20 but < or =35 mm; and 3) group III (n = 247): stented segment length >35 mm.

RESULTS

There was no significant difference in the incidence of subacute stent thrombosis among the three groups (0.4% in group I, 0.4% in group II, 1.2% in group III; p = NS). The minimal lumen diameter (MLD) after stenting was greater in group I than in group III (3.04 +/- 0.60 mm in group I, 3.01 +/- 0.54 mm in group II, 2.91 +/- 0.58 mm in group III; p < 0.05). At follow up, a smaller MLD was observed in group III as compared with group I and group II (2.04 +/- 0.93 mm in group I, 1.92 +/- 1.00 mm in group II, 1.47 +/- 0.97 mm in group III; p < 0.01). The restenosis rates were 23.9% in group I, 34.6% in group II and 47.2% in group III (p < 0.01). Using multivariate analysis, the longer stented segment, the angiographic reference vessel diameter and the percent diameter stenosis after stenting were independent predictors of restenosis.

CONCLUSIONS

The present study shows that a longer stented segment is an independent predictor of restenosis without an influence on the risk of subacute thrombosis.

Coronary stenting during rescue angioplasty after failed thrombolysis

Compared with primary angioplasty [percutaneous transluminal coronary angioplasty (PTCA)], rescue PTCA is associated with lower angiographic success and higher reocclusion rates, especially after thrombolysis with tissue-type plasminogen activator (tPA). Although stent placement during primary PTCA has been demonstrated to be safe and even to improve the angiographic results achieved by balloon-alone PTCA, there are few data on stent placement during rescue PTCA after failed thrombolysis. This study sought to assess the feasibility and safety of stent implantation during rescue angioplasty in myocardial infarction after failed thrombolysis. The study population consisted of 20 patients with acute myocardial infarction referred for rescue PTCA after failed thrombolysis consecutively treated with coronary stenting. The thrombolytic agent was tPA in 15 patients (75%), streptokinase in 1 (5%), and anisoylated streptokinase plasminogen activator complex (APSAC) in 1 (5%); 3 patients (15%) were included in the INTIME II study (tPA vs. lanoteplase). After stenting, aspirin 200 mg daily plus ticlopidine 250 mg b.i.d. were administered. Thirty stents (1.5+/-1.0 per patient) were implanted. Angiographic success was achieved in 19 patients (95%). Two patients (10%) died, both because of severe bleeding complications. One patient (5%) suffered a reinfarction, but no patients suffered postinfarction angina or needed new target vessel revascularization. Eighteen patients (90%) were discharged alive and free of events. All these patients remained asymptomatic and free of target vessel revascularization at 6-month follow-up. Stent placement during rescue PTCA after failed thrombolysis is feasible and safe and is associated with a good angiographic result and clinical outcome. Bleeding complications seem to be, however, the main limitation of this reperfusion strategy.

Does platelet glycoprotein IIb/IIIa receptor antibody improve in-hospital outcome of coronary stenting in high-risk thrombus containing lesions?

Coronary stenting in acute coronary syndromes probably increases the risk of acute stent thrombosis. Recently, use of platelet glycoprotein IIb/IIIa receptor antibody has been shown to improve percutaneous transluminal coronary angioplasty (PTCA) outcomes in high risk lesions. The purpose of this analysis was to determine safety and efficacy of platelet glycoprotein IIb/IIIa receptor antibody administration in patients receiving coronary stents in high-risk lesions. Between October 1995 and November 1996, 282 patients with acute ischemic syndromes received coronary stents at our center: 73 had thrombus containing lesions--40 presented with AMI and 33 with unstable angina and make up the study population. The mean age of these patients was 61+/-13 years, 56 were male, 35 had a history of myocardial infarctions (MI), 21 had prior coronary artery bypass graft (CABG), and 21 had prior PTCA. Coronary stenting was used for suboptimal result in 46 patients (63%), threatened closure in 25 patients (34%), and acute closure in 2 patients (3%). Platelet glycoprotein IIb/IIIa receptor antibody was administered during the procedure in 74% and after the procedure in 26%. A total of 115 stents were deployed (Gianturco-Roubin 80, Palmaz-Schatz 29, and Wallstent 6) in 24 LAD, 21 RCA, 15 LCX, and 13 saphenous vein graft (SVG) lesions. Procedural success was 100%. The mean diameter stenosis before and after intervention was 60%+/-31% and 4%+/-14%, respectively. In-hospital events included 1 Q-wave MI (1.4%), 13 non-Q-wave MI (18%), and 1 death (1.4%). There was no subacute stent thrombosis, emergency CABG, or repeat PTCA. Significant in-hospital bleeding complications were noted in seven (10%) patients, with five patients (6.8%) requiring blood transfusions. In this series of patients with acute ischemic syndromes associated with angiographic evidence of thrombus, combined use of platelet glycoprotein IIb/IIIa receptor antibody and stenting resulted in a very low incidence of subacute stent thrombosis and emergency target lesion revascularization. However, bleeding complications were higher than expected with conventional antiplatelet therapy following routine stenting.

Pathology of bailout coronary stenting in human beings

OBJECTIVES

The aim of this study was to perform detailed postmortem analysis of bailout coronary stenting to gain insights into the mechanism of success or failure of the procedure. Bailout stenting is increasingly used for acute or threatened arterial closure after angioplasty. Few pathologic data from bailout stenting have been reported.

METHODS AND RESULTS

The coronary arteries from 6 cases of bailout stenting were analyzed at autopsy. All stents were placed for extensive coronary dissection or abrupt vessel closure after balloon angioplasty. Twenty stents (11 Palmaz-Schatz and 9 Gianturco-Roubin stents) were placed in 8 coronary arteries, ranging from 1 to 5 stents per artery. After stenting, angiography showed good coronary flow in 3 of 6 cases. All patients died secondary to acute myocardial infarction. Histologically, in all cases, the stents were well opposed to the coronary artery wall, with a focally widely patent lumen by compression of the dissection plane. However, in 4 of 6 cases, there was residual dissection present in the nonstented portion of the arteries proximal, proximal to, and between stents or distal to the stented segment, resulting in focal luminal compression or obstruction. In 2 cases, bailout stenting effectively covered the dissection and prevented luminal compression.

CONCLUSIONS

Bailout stenting for dissection after balloon angioplasty restores lumen patency in the stented segment. Residual dissection in nonstented segments adversely affects outcome and supports the need for continued development of new stents with increased trackability and tapering designs to more effectively treat major coronary dissections.

Angiographic and clinical outcome following coronary stenting of small vessels: a comparison with coronary stenting of large vessels

OBJECTIVES

Stent implantation reduces restenosis in vessels > or =3 mm compared with balloon angioplasty, but few data are available for stents implanted in vessels <3 mm. The aim of this study was to evaluate immediate and follow-up patient outcomes after stent implantation in vessels <3 mm compared to stent implantation in vessels > or =3 mm.

METHODS

Between March 1993 and May 1996, a total of 1,298 consecutive patients (1,673 lesions) underwent coronary stenting. The study population was divided into two groups based on angiographic vessel diameter. In case of multivessel stenting, patients were randomly assigned only one lesion. Group I included 696 patients (696 lesions) in whom stents were implanted in vessels > or =3 mm, and group II included 602 patients (602 lesions) in whom stents were implanted in vessels <3 mm.

RESULTS

There was no difference in procedural success (95.4% in group I and 95.9% in group II), or subsequent subacute stent thrombosis (1.5% in group I and 1.4% in group II, p=NS). The postprocedure residual diameter stenosis was 3.31+/-12.4% in group I and -2.45+/-16.2% in group II. Angiographic follow-up was performed in 75% of patients, restenosis occurred in 19.9% of patients in group I and 32.6% in group II (p <0.0001). Absolute lumen gain was significantly higher in group I compared to group II, but absolute late lumen loss was similar in the two groups (1.05+/-0.91 mm in group I vs. 1.11+/-0.85 mm in group II, p=NS). Subsequently, the loss index was more favorable in group I (0.45 vs. 0.56; p=0.0006). Independent predictors of freedom from restenosis by multivariate logistic regression in the total population were: larger baseline reference diameter (odds ratio 2.032 p=0.006), larger postprocedure minimal stent cross-sectional area (odds ratio 1.190, p=0.0001) and shorter lesions (odds ratio 1.037, p=0.01). At long-term clinical follow-up, patients with small vessels had a lower rate of event-free survival (63% vs. 71.3%, p=0.007).

CONCLUSIONS

Coronary stenting can be performed in small vessels with a high success rate and low incidence of stent thrombosis. However, the long-term angiographic and clinical outcome of patients undergoing stent implantation in small vessels is less favorable than that of patients with large vessels.

[Initial results with the Multi-Link coronary stent]

INTRODUCTION AND OBJECTIVES

The Multi-Link intracoronary stent is a balloon-expandable stainless steel stent with an interconnected ring structure designed to provide a high degree of compressive resistance while preserving longitudinal flexibility. We present the results of our initial experience with the implantation of this stent.

PATIENTS AND METHODS

From May 1996 to April 1997, 124 Multi-link stents were implanted in 97 patients. Mean age 62.2 +/- 11 years. All patients included had a coronary artery diameter > 2.7 mm. Clinical presentation includes stable angina in 20, unstable angina in 72, and myocardial infarction in 5 patients. According to the ACC/AHA classification 6 lesions were type A, 72 type B and 19 type C. The implantation of the stent was for "de novo" lesions in 85 patients and for restenosis in 12. Patients were treated after the procedure with a combination of aspirin and ticlopidine, except six of them who received aspirin and acenocumarol. 16 patients were treated additionally with Abciximab. The degree of stenosis was determined by quantitative angiography.

RESULTS

The delivery of the stent was successful in all patients. The degree of stenosis before the procedure was 79.6 +/- 13.1%, and after the stent deployment was 17.7 +/- 11.4%. Three patients presented a non-Q-wave myocardial infarction, two patients had a subacute stent thrombosis, one of them died due to heart failure. During a follow-up of 4.7 +/- 2.6 months five patients were readmitted with recurrent angina (4 due to restenosis and one for vessel occlusion) and one patient with heart failure after myocardial infarction died suddenly three weeks after the dilatation.

CONCLUSIONS

The Multi-Link stent was implanted successfully in all patients with a low incidence of complications, showing at the follow-up a reduced rate of clinical restenosis.

Risk factors for acute and subacute stent thrombosis after high-pressure stent implantation: a study by intracoronary ultrasound

BACKGROUND

In the era of coronary stenting with high-pressure expansion, stent thrombosis remains a major life-threatening risk. Because of its superior imaging mode, intracoronary ultrasound could provide insight into potential risk factors for stent thrombosis.

PATIENTS AND METHODS

In 215 patients with stent implantations controlled by intracoronary ultrasound, four occurrences of subacute stent thrombosis, two complete acute thrombotic occlusions, and four occurrences of incomplete acute thrombosis were observed. All stents were expanded with inflation pressures of at least 14 atm ( 17+/-3 atm). The clinical data and the qualitative and quantitative ultrasound information were compared between stents with thrombosis and stents without thrombosis. The luminal area and the plaque border of the reference segments, and of the smallest and largest site of the stented segment after the initial and final expansion, were measured.

RESULTS

Stents in the left anterior descending artery were more often involved in stent thrombosis than other vessels, but the vessel dimensions in this target vessel were smaller than in the right coronary artery. The plaque burden was considerably larger after stent implantation with subsequent thrombosis compared with no thrombosis (74.1+/-8.8% vs 63.6+/-8.0%; p < 0.001), and the stent area was smaller (4.80%+/-1.33 mm2 vs 6.86+/-2.08 mm2; p < 0.01 ). In stents with thrombosis the plaque burden of the stent site with the smallest and largest lumen differed by 15.2%, whereas the difference in plaque burden in stents without thrombosis was 2.7%. Intracoronary ultrasound showed that the best risk predictor of thrombosis was the residual plaque burden of the stented segment (odds ratio 15.7 [confidence interval 2.4 to 104.7]), and a small stent area after implantation (odds ratio 6.8 [confidence interval 1.9 to 24.3]).

CONCLUSION

In a multivariate risk analysis plaque burden was the strongest independent risk factor for stent thrombosis. The amount of residual plaque mass around the stent might be a potential trigger for thrombus formation.

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.

Clinical outcome at six months of coronary stenting followed by ticlopidine monotherapy

Antiplatelet therapy has been shown to be superior to oral anticoagulation after coronary stent implantation. Different regimens for postinterventional antiplatelet therapy have been proposed. A combination of ticlopidine and aspirin has gained the most widespread use. The relative merit of the different compounds in this combination remains unclear. There are several, partly conflicting, reports on coronary stent implantation followed by aspirin alone, but data on ticlopidine monotherapy are scarce. We conducted a prospective trial of elective coronary stenting followed by ticlopidine monotherapy in 263 consecutive, unselected patients. One-, 2-, and 3-vessel disease was present in 42.9%, 42.6%, and 14.5% of patients, respectively. We deployed a total of 322 stents. All patients received 250 mg of ticlopidine twice daily for up to 6 months. The clinical end points encountered during the hospital stay and at 5.9+/-2.9 months, respectively, were: death (2 [0.8%] and 2 [0.8%]); myocardial infarction (5 [1.9%] and 4 [1.5%]); target vessel occlusion (2 [0.8%] and 4 [1.5%]); bypass surgery (0 and 2 [0.8%]); and repeat angioplasty (2 [0.8%] and 52 [19.8%]). There was 1 vascular surgery (0.4%) and 4 (1.5%) non-procedure-related ischemic cerebrovascular events at follow-up. We conclude that coronary stent deployment followed by ticlopidine monotherapy is safe and effective in an unselected population. The overall clinical outcome at 6 months is good and comparable to that of patients treated with combined antiplatelet therapy. Ticlopidine monotherapy may be a safe alternative for patients with contraindications to aspirin.

Clinical and angiographic outcome of Micro Stent II implantation in native coronary arteries

To evaluate immediate success and 6-month restenosis rate, 70 Micro Stents II were implanted for 65 stenoses in 63 patients (age 59+/-9 years). Stable angina pectoris was present in 47% of the patients (38% class I to III; 9% class IV), whereas 32% had postinfarction angina and 21% had unstable angina. Indications for stent implantation were elective in 62% and semi-elective in 38% of the patients. Sixty-two percent of the patients received ticlopidin and acetylsalicylic acid for 28 days, whereas 38% of the patients received only acetylsalicylic acid. All stents were deployed successfully at the target site. Subacute closure occurred in 2 patients (3%), both of whom were not treated with ticlopidin. Two other patients (3%) developed non-Q-wave infarction after side branch occlusion during the procedure. The minimum lumen diameter increased from 1.0+/-0.5 mm to 2.8+/-0.4 mm after stent implantation. At follow-up the loss in diameter was 0.9+/-0.6 mm, indicating a net gain of 0.9+/-0.8 mm. Late clinical events (4 weeks to 6 months) were coronary angioplasty of a stented segment (3%), coronary angioplasty of a nonstented segment (10%), and coronary artery bypass grafting (2%). No deaths or myocardial infarction occurred. The procedural success rate was 94% and the event-free survival at 6-month follow-up was 79%. Micro Stent II implantation can be done with a high rate of immediate success and good 6-month outcome. The Micro Stent II has proven to be a versatile device that can also be used in patients with less favorable coronary anatomy or lesion characteristics.

Stent implantation in patient with visible intracoronary thrombus and compromised left ventricular function, after local thrombolysis using the Dispatch catheter

The case of a patient with unstable angina and angiographic findings of significant (approximately 90%) right coronary artery stenosis with an intracoronary thrombus next to the lesion, total left anterior descending and circumflex occlusion and an ejection fraction of approximately 22% is described. The case was treated with stent implantation after local thrombolysis with the use of the Dispatch infusion catheter.

Multiple coronary stenting in unstable angina: early and late clinical outcomes

We examined clinical outcomes in 110 consecutive patients with unstable angina who underwent multiple coronary stenting over a 32-mo period. The main outcome measures were death, stroke, myocardial infarction, bypass surgery, and repeat angioplasty. The angiographic success rate was 100%, and the procedural success rate was 96%. There were no in-hospital deaths and five (4.5%) patients had a myocardial infarction prior to discharge. There were four (3.6%) stent thromboses with one (0.9%) patient requiring urgent bypass surgery and two (1.8%) requiring repeat angioplasty. At late follow-up (11.9+/-7.1 mo), there was (0.9%) death and three patients (2.8%) suffered myocardial infarction. Three (2.8%) patients underwent late bypass surgery and five (4.6%) had a repeat angioplasty. At follow-up, 86% of patients were event free. We conclude that multiple coronary stenting in unstable angina may be performed with a high procedural success rate and good long-term outcome.

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.

Prospective, multicenter study of the safety and feasibility of primary stenting in acute myocardial infarction: in-hospital and 30-day results of the PAMI stent pilot trial. Primary Angioplasty in Myocardial Infarction Stent Pilot Trial Investigators

OBJECTIVES

The goals of this study were to examine the safety and feasibility of a routine (primary) stent strategy in acute myocardial infarction (AMI).

BACKGROUND

Limitations of reperfusion by primary percutaneous transluminal coronary angioplasty (PTCA) in AMI include in-hospital recurrent ischemia or reinfarction in 10% to 15% of patients, restenosis in 37% to 49% and late infarct-related artery reocclusion in 9% to 14%. By lowering the residual stenosis and sealing dissection planes created by PTCA, primary stenting may further improve short- and long-term outcomes after mechanical reperfusion.

METHODS

Three hundred twelve consecutive patients treated with primary PTCA for AMI at nine international centers were prospectively enrolled. After PTCA, stenting was attempted in all eligible lesions (vessel size 3.0 to 4.0 mm; lesion length < or = 2 stents; and the absence of giant thrombus burden after PTCA, major side branch jeopardy or excessive proximal tortuosity or calcification). Patients with stents were treated with aspirin, ticlopidine and a 60-h tapering heparin regimen.

RESULTS

Stenting was attempted in 240 (77%) of 312 patients, successfully in 236 (98%), with Thrombolysis in Myocardial Infarction grade 3 flow restored in 230 patients (96%). Patients with stents had low rates of in-hospital death (0.8%), reinfarction (1.7%), recurrent ischemia (3.8%) and predischarge target vessel revascularization for ischemia (1.3%). At 30-day follow-up, no additional deaths or reinfarctions occurred among patients with stents, and target vessel revascularization was required in only one additional patient (0.4%).

CONCLUSIONS

Primary stenting is safe and feasible in the majority of patients with AMI and results in excellent short-term outcomes.

Clinical one-year outcomes after stenting in acute myocardial infarction

We retrospectively review our results of 96 stent placements in 64 patients identified from our data base who received stents acutely and within 48 hr of acute myocardial infarction. The average age was 60 years; 77% were male. The average length of stay was 6.75 days. Three patients needed coronary artery bypass grafting (CABG) before discharge: 2 for stent occlusion and 1 for papillary muscle rupture. Need for CABG, further percutaneous transluminal coronary angioplasty (PTCA), myocardial infarction, and death defined outcome. Mean patient follow-up was 10.3 (+/-5.3) months. Seventy-two percent of patients were free of outcome events at 1 year, 17% needed CABG, and 11% required further PTCA. There were 2 myocardial infarctions and 1 death. Presence of left bundle branch block on admission electrocardiogram and angina in hospital after stent placement predicted worse outcome (P < 0.01).

Clinical and angiographic implications of coronary stenting in thrombus-containing lesions

OBJECTIVES

This study sought to determine the results of coronary stenting in thrombus-laden lesions.

BACKGROUND

The angiographic evidence of intracoronary thrombus has classically been considered a formal contraindication to stent implantation. However, with increasing use of stenting, the indications for this technique have widened to include treatment of patients who have an acute coronary syndrome or lesions with adverse anatomic features.

METHODS

We studied 86 consecutive patients (mean age +/- SD 61 +/- 11 years, 14 women) undergoing coronary stenting of a thrombus-containing lesion; the procedure was performed electively in 39% and after angioplasty failure in 61%. Sixty-four patients (75%) were treated for unstable angina, and 19 (22%) underwent the procedure during an acute myocardial infarction. A specific protocol that included clinical and late angiographic follow-up was used.

RESULTS

Angiographic success was obtained in 83 patients (96%). Five patients (6%) died during the hospital stay despite angiographic success; four of these had cardiogenic shock, and one (1%) had subacute stent thrombosis. Non-Q wave myocardial infarction developed in five additional patients (6%), and four of these five had data consistent with distal embolization. Of the 78 patients discharged with angiographic success, 67 (86%) were event-free and clinically improved at last follow-up visit (12 +/- 11 months). During the follow-up period, eight patients required repeat angioplasty, one patient required heart transplantation, and two patients died. Quantitative angiography demonstrated excellent angiographic results after stenting (minimal lumen diameter 0.31 +/- 0.4 vs. 2.77 +/- 0.6 mm). Late angiographic follow-up (5.5 +/- 1 months) was obtained in 50 patients with 54 lesions (93% of eligible), revealing a minimal lumen diameter of 2.0 +/- 1 mm and restenosis (lumen narrowing > 50%) in 18 lesions (33%).

CONCLUSIONS

Coronary stenting constitutes an effective therapeutic strategy for patients with thrombus-containing lesions, either after failure of initial angioplasty or electively as the primary procedure. Coronary stenting in this adverse anatomic setting results in a high degree of angiographic success, a low incidence of subacute thrombosis and an acceptable restenosis rate.

Early and late assessment of the Micro Stent PL coronary stent for restenosis and suboptimal balloon angioplasty

This prospective study represents the initial assessment of the Micro Stent PL (Arterial Vascular Engineering, Inc.) coronary stent. From one to three radiopaque stainless steel stents, each measuring 4 mm long, were premounted onto specially designed balloon catheters. A total of 123 stents were implanted in 41 patients without procedural failure or complications. Stent dislodgment proved a concern, with 7 of 123 stents (5.7%) moving > 3 mm from the site of placement and late downstream migration occurring in an additional patient. Subacute stent thrombosis occurred in two patients (5%). Six-month angiographic follow-up was available in 37 of 41 patients (90%). Minimal lumen diameter at baseline was 0.93 +/- 0.51 mm, increasing to 2.74 +/- 0.49 mm after stenting, and falling to 1.66 +/- 0.89 mm at 6 months; this represents a late loss of 60% of the initial gain. Restenosis, based on a binary definition of > 50% diameter stenosis, was documented in 18 patients (49%). Advantages of the Micro Stent PL include its radiopacity and marked ease of distal delivery. The potential for stent dislodgment has implications for future stent designs. The role of the Micro Stent PL in managing restenosis is unclear, but it appears useful in the management of dissection and threatened closure after balloon angioplasty.

Subacute stent thrombosis in the era of intravascular ultrasound-guided coronary stenting without anticoagulation: frequency, predictors and clinical outcome

OBJECTIVES

This study was performed to determine predictors of subacute stent thrombosis (SST) in the era of intravascular ultrasound (IVUS)-guided coronary stenting without anticoagulation.

BACKGROUND

The incidence of stent thrombosis has declined with the application of high pressure stent deployment with only antiplatelet therapy. However, no data are available on predictors of stent thrombosis in this era.

METHODS

Between March 30, 1993 and July 31, 1995, 1,042 consecutive patients underwent coronary stenting without anticoagulation. For this analysis, we excluded patients who underwent coronary artery bypass surgery, died or had acute stent thrombosis within the 1st 24 h after stenting (41 patients). A total of 1,001 patients (1,334 lesions) were included; 982 patients (1,315 lesions) without SST and 19 patients (19 lesions) with SST.

RESULTS

The rate of SST was 1.9% (per patient). There was no difference between the SST and No SST groups in rescue stenting (12% vs. 13.5%, p = 1.0) or mean +/- SD reference diameter (3.11 +/- 0.58 vs. 3.19 +/- 0.53 mm, p = 0.54). A preexisting thrombus was present in 12% of the SST group and in 4.5% of the No SST group (p = 0.19). Predictors of SST by univariate analysis were low ejection fraction (p = 0.004), more stents per lesion (p = 0.049), use of combination of different stents (p = 0.012), smaller balloon size (p = 0.012) and suboptimal result in terms of smaller lumen dimensions by angiography (p = 0.016) and IVUS (p = 0.004), residual dissections (p = 0.027) and slow flow (p = 0.0001). In stepwise logistic regression analysis, ejection fraction (p = 0.019), use of a combination of different stents (p = 0.013) and postprocedure dissections (p = 0.014) and slow flow (p = 0.0001) were predictive of SST.

CONCLUSIONS

In the present era of stent implantation, factors that may predispose to SST are low ejection fraction, intraprocedural complications leading to utilization of more stents, particularly with different stent designs, and suboptimal final result in terms of smaller lumen dimensions and persistent slow flow and dissections.

Early clinical experience with the Multi-Link coronary stent

The Multi-Link coronary stent (Advanced Cardiovascular Systems, Santa Clara, CA) is a balloon expandable stent carved from a stainless steel cylinder and is composed of 12 corrugated rings connected by multiple links. This design gives the stent great flexibility and conformity as well as radial strength. For the 3 month period from November 1995 to January 1996, all patients undergoing stent implantation in our institution were treated with this device, except for vessels smaller than 2.7 mm or larger than 3.7 mm in diameter, left main disease, or those who could not tolerate anticoagulation therapy. Forty patients, with a total of 42 arteries or 44 lesions, were treated with 56 stents, or 1.33 stents per artery. Clinical presentation included stable angina in 13 (32.5%), unstable angina in 24 (60%), acute myocardial infarction in 2 (5%), of whom 1 was in cardiogenic shock, and atypical symptoms with an abnormal thallium stress test in 1 (2.5%). According to the American College of Cardiology/ American Heart Association (ACC/AHA) classification, 8 lesions (18%) were type A, 14 (32%) type B1, 11 (25%) type B2, and 11 (25%) type C. Forty-three lesions (97.7%) were de novo and 1 (2.3%) restenotic. Stent delivery was successful in all patients. Complications included 1 balloon rupture at 7 atm but without sequelae, and 2 patients in whom the coronary guide wire became kinked and locked inside the catheter shaft of the stent delivery system but stent delivery was eventually successful. Mean diameter stenosis was reduced from 76 +/- 13% presenting to 2 +/- 9% poststenting and minimal lumen diameter increased from 0.87 +/- 0.38 to 2.82 +/- 0.34 mm. There were no acute-subacute stent thromboses, bleeding/vascular complications, or major cardiac events such as myocardial infarction, coronary artery bypass surgery, or death during a follow-up period of 2-5 months (mean 3.6 months). In conclusion, our early clinical experience with the Multi-Link stent is very encouraging, with a very high rate of successful delivery and minimal complications.