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.

Comparison of angiographic and clinical outcomes of coronary stenting of chronic total occlusions versus subtotal occlusions.

The objective of this study was to assess the short- and long-term outcome of patients undergoing coronary stenting for chronic total occlusions compared with a control patient population with nonocclusive stenoses. A total of 789 consecutive patients (1,043 lesions) underwent coronary stenting using a high-pressure stent optimization technique. The study population was divided into total occlusion group (94 consecutive patients [95 lesions] with chronic total occlusions) and subtotal occlusion group (695 consecutive patients [948 lesions] with nonocclusive stenoses). There was no difference in post-procedure angiographic minimum lumen diameter (3.13 +/- 0.48 vs 3.15 +/- 0.57 mm, p = 0.72) and minimum intrastent cross-sectional area by intravascular ultrasound (7.31 +/- 2.06 vs 7.64 +/- 2.53 mm2, p = 0.26) between the total and subtotal groups, respectively. Subacute thrombosis occurred in 2 patients (2.1%) in the total group compared with 9 patients (1.3%) in the subtotal group (p = 0.63). Angiographic restenosis occurred in 27% vs 22% (p = 0.40) and repeat angioplasty in 15% vs 13% (p = 0.62) in the total and subtotal groups, respectively. Thus, coronary stenting of chronic total occlusions after successful recanalization could be performed with a high success rate. In addition, the incidence of stent thrombosis, angiographic restenosis, and the need for target lesion revascularization is comparable to that of an unselected cohort of patients with nonocclusive stenoses.

Long-term clinical follow-up after successful repeat percutaneous intervention for stent restenosis.

OBJECTIVES: This study evaluated the long-term clinical outcome of successful repeat percutaneous intervention after in-stent restenosis. BACKGROUND: Recurrence of symptoms and angiographic restenosis after stent implantation are observed in 15% to 35% of cases. Repeat percutaneous treatment for in-stent restenosis has been shown to be safe, with high immediate success, but little is known about the long-term clinical outcome. METHODS: Clinical follow-up (minimum 9 months) was obtained in a consecutive series of 124 patients (127 vessels) presenting with stent restenosis who were successfully treated with repeat percutaneous intervention. RESULTS: Clinical follow-up was obtained in all 124 patients at a mean [+/-SD] of 27.4 +/- 14.7 months (range 9 to 66); a stress test was available in 88 patients (71%). Recurrence of clinical events occurred in 25 patients (20%) and included death from any cause in 2 patients (2%), target vessel revascularization in 14 (11%), myocardial infarction in 1 (1%) and positive stress test results or recurrence of symptoms (Canadian Cardiovascular Society class I to IV) treated medically in 8 (6%). Cumulative event-free survival at 12 and 24 months was 86.2% and 80.7%, respectively. Significant predictive factors of recurrence of clinical events were repeat intervention in saphenous vein grafts, multivessel disease, low ejection fraction and a < or = 3-month interval between stent implantation and repeat intervention. CONCLUSIONS: In-stent balloon angioplasty for stent restenosis in native vessels seems to be an effective method in terms of a low long-term clinical event rate.

Transcatheter repair of a large coronary pseudoaneurysm using ultrasound guidance and vein-covered stents.

This case-report describes a large pseudoaneurysm of the proximal left anterior descending coronary artery, fissured in the pericardium, developed 4 days after rotational and directional atherectomy followed by stent implantation. A successful percutaneous repair was obtained with 2 vein-covered stents implanted and expanded under ultrasound guidance.

New approach to quantitative angiographic assessment after stent implantation.

The new generation quantitative angiographic systems apply the interpolated technique to calculate the reference diameter at the site of the stenosis by integrating measurements of the segments proximal and distal to the stenosis. After stent implantation these measurements can be misleading as the treated segment, which is frequently larger than the adjacent not stented segments, is included in the measurements. The consequence is an overestimation of the reference diameter and the residual diameter stenosis. The present study was performed to compare this conventional technique of measurement with a new method which excludes the stented segment for the calculation of the reference diameter. Fifty-two lesions treated with poorly radiopaque stents (56% Palmaz-Schatz, 28% NIR, 10% Gianturco-Roubin, 6% Wallstent) expanded at high pressure (> = or 16 atm) were analyzed according to the conventional and stent excluded method. After stent implantation the reference diameter was 3.39 +/- 0.48 mm with conventional measurements and 3.02 +/- 0.45 mm with the stent excluded method (P < 0.05). The corresponding % diameter stenosis was 13 +/- 9 for the conventional technique and 1 +/- 13 for the stent excluded analysis (P < 0.05). The new approach to quantitative coronary analysis after stenting provides higher accuracy in reference diameter calculations and allows a more appropriate matching of stented segments with adjacent normal segments.

Results of a consecutive series of patients receiving only antiplatelet therapy after optimized stent implantation. Comparison of aspirin alone versus combined ticlopidine and aspirin therapy.

BACKGROUND: Previous studies have shown that stents can be inserted in coronary arteries of patients who are subsequently treated safely with antiplatelet therapy only (ticlopidine and/or aspirin) with a low incidence of stent thrombosis, provided that stent expansion is adequate and there are no other flow-limiting lesions present. However, it is unknown whether ticlopidine combined with aspirin is superior to aspirin alone in preventing stent thrombosis. METHODS AND RESULTS: From March 1993 through July 1995, 801 consecutive patients assigned to receive either aspirin therapy alone (ASA, 264 patients, 348 lesions) or a combination of ticlopidine and aspirin (TIC-ASA, 537 patients, 737 lesions) after a successful stent insertion, in most accomplished with intravascular ultrasound guidance, were evaluated retrospectively. At 1 month, there was no difference in the ASA group compared with the TIC-ASA group in the rate of any stent thrombosis (1.9% versus 1.9%; P = 1), subacute stent thrombosis (1.9% versus 1.3%; P = .5), cumulative major adverse clinical events (1.9% versus 2.0%; P = 1), and peripheral vascular complications (0.5% versus 0.2%; P = .3). Medication side effects that required termination of antiplatelet therapy occurred only in 1.9% of patients in the TIC-ASA group (P = .04). CONCLUSIONS: At 1-month clinical follow-up, stent thrombosis and other adverse clinical outcomes were not significantly different between the ASA and TIC-ASA groups. Medication side effects occurred only in patients treated with ticlopidine. These results provide further evidence of the safety of treatment with antiplatelet therapy only after optimal stent implantation and support the efficacy of aspirin alone in preventing stent thrombosis.

Intracoronary stent implantation in native coronary arteries and saphenous vein grafts: a consecutive experience with six types of stents without prolonged anticoagulation.

OBJECTIVE: To analyze the results of implantation of six different intracoronary stents without the use of prolonged anticoagulation. MATERIAL AND METHODS: Between Mar. 30, 1993, and Jun. 30, 1995, 889 patients with 1,194 coronary or vein graft lesions underwent implantation of one of six types of stents-Palmaz-Schatz, Gianturco-Roubin, Wiktor, Micro, Cordis, or Wallstent. The patients were classified into seven groups on the basis of the type of stent that was implanted, including one group with combined use of two or more types of stents. Among the 851 patients with successful stent delivery and without major complications, 801 received only antiplatelet therapy, and 50 received a standard anticoagulation regimen. One-month clinical followup data were obtained in all patients, and clinical events were investigated. RESULTS: The mean number of stents was 1.8 per lesion and 2.4 per patient. Procedural success was achieved in 93% of the lesions. The clinical success rate at 1 month was 90%. Intravascular ultrasound assessment was performed in 90% of the lesions. The final minimal luminal cross-sectional area of the stent increased from 6.8 to 7.8 mm2 after intravascular ultrasound-guided optimization. Within 1 month, 16 stent thrombosis events (1.9%) occurred. No significant differences were noted in stent thrombosis rates among the various stent cohorts. Multivariate logistic regression analysis revealed that the final stent minimal luminal diameter measured by intravascular ultrasonography was the only variable associated with stent thrombosis. CONCLUSION: This study showed that six different stents could possibly be inserted without subsequent anticoagulation if optimal stent expansion and total lesion coverage were achieved.

Coronary stenting in 1000 consecutive patients. Long-term clinical and angiographic results.

Coronary stent implantation has become an accepted treatment for selected patients but the long-term outcome after stent implantation has not been investigated in a large unselected population. This study reports clinical and angiographic results after coronary stent implantation in a consecutive group of 1000 patients treated between November 1989 and June 1994. A total of 2012 stents were implanted in 1216 lesions. The anticoagulation regimen after successful stenting was abolished in the last 499 patients, treated with aspirin and ticlopidina. Complex lesions (type B2, type C lesions and chronic total occlusions) were less frequent in the group with anticoagulation (67%, 355/529 lesions) than in the group without anticoagulation (76%, 485/641; p < 0.01). Vessel size was also significantly smaller in the group with no anticoagulation (3.21 +/- 0.50 mm vs 2.89 +/- 0.70 mm; p < 0.001). Procedural success was achieved in 96% of cases. Major complications occurred in 49 pts, including death (1%), emergency bypass surgery (2.7%), and myocardial infarction (2.1%). Subacute stent thrombosis, observed in 2.6% of the patients treated with anticoagulation, decreased to 1% in the last 499 patients receiving only antiplatelet drugs after high pressure stent expansion controlled with intravascular ultrasound (p < 0.05). Angiographic follow-up was obtained at a mean interval of 6.6 +/- 3.0 months in 718 patients (75% of the eligible candidates). The global restenosis rate (greater than 50% diameter stenosis) was 22%, with no statistically significant difference in patients with and without anticoagulation after stenting. Clinical follow-up was available in 890 patients at a mean interval of 14 +/- 17 months. Late cardiac events occurred in 251 patients and included: 159 repeat coronary angioplasties for restenosis (20%), 114 coronary angioplasties for de novo lesions (10%), 33 elective by-pass surgery operations (3.7%) and 42 late deaths (4.7%). At the most recent follow-up there were 719 pts (81%) free of anginal symptoms, including patients having repeat angioplasty for restenosis or disease progression. Coronary stenting has a low incidence of procedural complications and high-pressure ultrasound guided implantation has drastically reduced the risk of subacute thrombosis. Repeat procedures due to restenosis remain the most important limitation of the technique and do not seem to be affected by evolving technique and operator experience.

Results of coronary stenting for restenosis.

OBJECTIVES: This study attempted to analyze immediate and long-term angiographic and clinical results of coronary stent implantation for restenosis in a consecutive group of patients. BACKGROUND: The rate of stent utilization in patients with coronary artery disease has increased exponentially in recent years. There are many unanswered questions about the use of stenting in patients with restenosis, particularly with respect to late clinical and angiographic results. METHODS: A total of 159 stents were implanted in 128 consecutive patients with 139 lesions (mean 1.3 stents/patient). A technique of optimal stent expansion was used in all patients, and intravascular ultrasound guidance with no subsequent anticoagulation was performed in 41 patients. RESULTS: Stent implantation was successful in 126 patients (98%). Four patients (3.1%) had complications (in two after successful stenting): death in one, emergency bypass surgery operation in two and subacute stent thrombosis in one. Stents were implanted with a final balloon size (mean +/- SD) of 3.5 +/- 0.5 mm and a mean maximal pressure of 11 +/- 4 atm (range 8 to 20). Angiographic restenosis occurred in 27 patients (25%). Regression analysis on clinical and angiographic variables for prediction of restenosis showed no statistical significance for any variable. Late events occurred in 23 patients (19%). The actuarial survival rate was 98% at 1 year and at 3 years, and the event-free survival rate including freedom from repeat angioplasty for restenosis was 95% and 76%, respectively. CONCLUSIONS: The late angiographic outcome, restenosis rate and total clinical events are favorable for selected patients undergoing stent implantation for the indication of restenosis.

Subacute stent thrombosis and the anticoagulation controversy: changes in drug therapy, operator technique, and the impact of intravascular ultrasound.

Clinical trials have shown that stents are superior to other catheter-based coronary interventions in terms of reduced complications and improved long-term efficacy. With utilization of high-pressure balloon inflation and intravascular ultrasound (IVUS) guidance, stent implantation can now be performed safely without anticoagulation (i.e., with lower rates of stent thrombosis and vascular complications). In 2 recent prospective clinical trials, stent thrombosis occurred in 3.5% of cases despite anticoagulant therapy, which resulted in an average of 7% vascular and bleeding complications. Initial use of IVUS during traditional stent deployment showed that 80% of stents were underexpanded and led to the hypothesis that stent thrombosis might be decreased as a result of optimal stent placement under IVUS guidance without the need for anticoagulation. In a prospective clinical trial to test this hypothesis, three factors were found to reduce stent thrombosis: full stent expansion, complete apposition to the vessel wall, and full lesion coverage. Predictors of thrombotic risk in this era of high-pressure stent deployment without anticoagulation include low ejection fraction, residual dissections, slow flow, multiple stents per lesion, and smaller postprocedure stent luminal diameter. To optimize stent expansion, stent dilation should be performed using a mean inflation pressure of 18 atm with a noncompliant or minimally compliant balloon sized to the vessel being treated (B/V ratio = 1.1). Controversy still remains about the best poststent antiplatelet regimen, and results of a recent trial should indicate whether heparin coating provides additional protection from stent thrombosis.

Successful closure of a coronary vessel rupture with a vein graft stent: case report.

We report a successfully percutaneous closure of a brisk coronary artery rupture with a custom-made "vein graft stent," a Palmaz-Schatz stent covered with a vein graft. This method is an elegant and effective alternative to the traditional surgical approach and should be considered whenever technically and clinically feasible.

Implantation of the peripheral Wallstent for diffuse lesions in coronary arteries and vein grafts.

The Wallstent (Schneider, Bulach, Switzerland) is available in different lengths without much compromise in flexibility and radial support compared to some other stents. We treated 24 patients (26 vessels) with diffuse coronary lesions or vein graft lesions with intravascular ultrasound-guided peripheral Wallstent implantation. Average balloon pressure during stent optimization was 16.4 +/- 2.7 atm. The stents could be successfully implanted in 24 vessels. Minimal lumen diameter and percent diameter stenosis after stenting were 3.60 +/- 0.62 mm and -8 +/- 13%, respectively. Average stent length was 63.7 +/- 22.7 mm. There was one procedure-related complication. After stenting, all patients were treated only with antiplatelet agents. During 1-month follow-up, there was one subacute stent thrombosis due to incomplete coverage of a distal dissection. These preliminary results show the feasibility of this novel approach in selected lesions.

Acute recoil of Palmaz-Schatz stent: a rare cause of suboptimal stent implantation--report of two cases with intravascular ultrasound findings.

It is generally believed that the Palmaz-Schatz stent maintains a strong radial force, preventing stent recoil. However, the capacity to prevent recoil is largely governed by the hardness or resistance of the lesion. We report two cases of "acute Palmaz-Schatz stent recoil," documented by intravascular ultrasound, and suggest a novel treatment of this unusual problem.

A randomized comparison of combined ticlopidine and aspirin therapy versus aspirin therapy alone after successful intravascular ultrasound-guided stent implantation.

BACKGROUND: Previous studies have shown that it is feasible to withhold anticoagulation after a successful intracoronary stent procedure with a low incidence of stent thrombosis. The importance of specific antiplatelet agents when stenting is performed without anticoagulation is unknown. METHODS AND RESULTS: After successful intravascular ultrasound-guided stenting, 226 patients were randomly assigned to receive either aspirin therapy alone (n = 103) or a combination of ticlopidine and short-term aspirin therapy (n = 123). Primary angiographic and clinical end points were stent thrombosis, death, myocardial infarction, the need for postprocedure coronary artery bypass surgery or repeated angioplasty, and significant medication side effects requiring termination of the medication within the first month of a successful procedure. At 1 month, the rate of stent thrombosis was 2.9% in the aspirin only group and 0.8% in the ticlopidine-aspirin group (P = .2). Cumulative major clinical events after successful stenting occurred in 3.9% of the patients in the aspirin group and in 0.8% in the ticlopidine-aspirin group (P = .1). There were no medication side effects in the aspirin group; in the combined ticlopidine-aspirin group, medication side effects occurred in 3 patients (P = .2). CONCLUSIONS: At 1 month, there was no difference in the incidence of stent thrombosis or other clinical end points between the two poststent antiplatelet regimens. However, the relatively small size of the study and the low incidence of thrombosis events may have contributed to the failure to detect differences in angiographic and clinical end points between the two groups.

[Clinical results and modification of left ventricular function after emergency revascularization for acute myocardial infarction]. / Risultati clinici e modificazioni della funzione ventricolare sinistra dopo rivascolarizzazione d'emergenza per infarto miocardico acuto.

Results of emergency revascularization for evolving myocardial infarction have been evaluated in 43 consecutive patients operated between January 1985 and March 1988. Time interval between onset of symptoms and coronary bypass averaged 6.7 +/- 0.5 hours (0.75-48). Intravenous or intracoronary thrombolysis was attempted pre-operatively in 26 cases. Overall hospital mortality was 6.9% (3/43) but this decreased to only 2.7% if patients in cardiogenic shock were excluded. Follow-up averaged 20.6 +/- 9.5 months (4-42). Actuarial survival was 82.9 +/- 7.3% at 36 months. Of the 36 survivors, 28 were free from angina and reinfarction at control. Nineteen patients were evaluated with angiography at follow-up (averaging 10.1 +/- 5.7 months). Left ventricular and regional ejection fraction were calculated on pre- and post-operative angiograms; regional ejection fraction was determined with the centerline method. Left ventricular ejection fraction increased from 0.49 +/- 0.15 to 0.52 +/- 0.19 (NS), regional ejection fraction improved from 0.20 +/- 0.1 to 0.27 +/- 0.16 (35% increment, p less than 0.05). The analysis of left ventricular and regional ejection fraction variations with the time elapsed from the onset of symptoms to surgery identified two subgroups of patients: those operated within and after six hours. In the first subgroup, left ventricular ejection fraction increased from 0.52 +/- 0.16 to 0.62 +/- 0.13 (p less than 0.005) and regional ejection fraction from 0.19 +/- 0.08 to 0.36 +/- 0.14 (89% increment, p less than 0.0005). In the second subgroup, both left ventricular and regional ejection fractions decreased from 0.44 +/- 0.13 to 0.36 +/- 0.11 (NS) and from 0.20 +/- 0.13 to 0.12 +/- 0.08 (NS), respectively. These results lead to the conclusion that improved left ventricular performance may be achieved in selected groups of patients if they undergo surgery within six hours of the onset of pain.