Long-term follow-up of the first 56 patients treated with intracoronary self-expanding stents (the Lausanne experience)

The Comparison between Self-Expanding and Balloon Expandable Stent Results in Left Anterior Descending Artery

The first Wallstent results had high thrombosis and death. It was reported that the left anterior descending (LAD) artery was the vessel implicated in major complications that occurred in patients who received a Wallstent. Subsequently, Wallstent applications were refrained from with LAD lesions. However, the promising results of second-generation self-expanding Magic Wallstent implantation have been reported recently. The purpose of this study is to assess the immediate and intermediate clinical outcomes of patients undergoing self-expanding Magic Wallstent implantation at the LAD site and to compare those outcomes with those of a similar group of patients undergoing balloon expandable stenting at the same site. Between 1995 and 1999, 255 consecutive patients underwent LAD stenting at our center. The study population was divided into two groups based on the mode of delivery (self-expanding versus balloon-expandable) of stent design. Group I included 97 patients in whom self-expanding Magic Wallstents were implanted. Group II included 158 patients in whom various types of balloon-expandable stents were implanted. Procedural success was defined as successful deployment of the stent in the absence of adverse cardiac events (death, acute myocardial infarction, emergency coronary bypass surgery). Clinical success was defined as the absence of adverse cardiac events (death, acute myocardial infarction, emergency coronary bypass surgery, repeat balloon angioplasty) within the first two weeks. The mean follow-up period was 8 +/- 5.3 months for Group I and 9.8 +/- 7.5 months for Group II. There was no difference in baseline characteristics between the two groups. Fourteen patients in Group I and 22 patients in Group II had bailout procedures. The number of patients with reference vessel diameter less than 3 mm was 37 in Group I and 60 in Group II. The stent length was greater in Group I than in Group II (p = 0.0003). In Group I, stenting improved minimal lumen diameter (MLD) from 0.65 +/- 0.4 mm to 2.35 +/- 0.4 and percent diameter stenosis (PDS) from 76.24 +/- 17.3 to 22.78 +/- 13.6. In Group II, stenting improved MLD from 0.73 +/- 0.4 mm to 2.49 +/- 0.5 and PDS from 76.71 +/- 15.5 to 18.99 +/- 9.6. Final MLD and final PDS improved more in Group II than Group I. Stent could not be delivered in three patients in Group I and nine in Group II. In Group II, six stents were dislocated from its delivery system. Procedural and clinical success and subacute stent thrombosis rates were 93.8%, 85.6%, and 7.2% in Group I, and 93%, 86.7%, and 5.1% in Group II, respectively. Within the first two weeks, death occurred in one patient in each group, acute myocardial infarction in four (Group I) and two (Group II) patients; coronary bypass surgery in three (Group I) and five (Group II) patients, and balloon angioplasty in two (Group I) and four (Group II) patients, respectively. In Group I, following the first two weeks, no patients died, two patients had nonfatal myocardial infarction, and coronary bypass surgery and target vessel repeat balloon angioplasty was required in five and ten patients, respectively. In Group II, one patient died in the follow-up period, there was no nonfatal myocardial infarction, and bypass surgery and target vessel repeat balloon angioplasties were required in three and eleven patients, respectively. None of these differences in clinical events was statically significant. We found that self-expanding Magic Wallstent implantation can be performed in LAD lesions and was associated with a rate of early clinical results and intermediate term clinical results similar to that of balloon-expandable stents in LAD arteries. In conclusion, the Magic Wallstent may confidently be used for LAD lesions. </hea

Angiographic and clinical restenosis following the use of long coronary Wallstents

This study assessed clinical and angiographic restenosis following the deployment of the long coronary Wallstent. Between May 1995 and June 1997, 182 Wallstents were deployed in 162 vessels in this unit. Forty-eight percent had an unstable coronary syndrome and 94% had AHA grade B or C lesions. The mean lesion length was 37 +/- 20 mm and the mean stent length was 48 +/- 20 mm. The procedural success rate was 99% and the primary success rate was 93%. Six in-patients suffered subacute stent thrombosis, the majority being in the era of anticoagulation rather than antiplatelet regimes. Seventy-three percent remained free of major adverse clinical events in the follow-up period, but 41% had angiographic restenosis. The Wallstent can be deployed in complex lesions with a high primary success rate and an acceptably low restenosis rate. The optimal management of in-stent restenosis remains to be defined.

Long term outcome after coronary stent implantation: a 10 year single centre experience of 1000 patients

OBJECTIVE

To describe the long term clinical outcome (up to 11 years) after coronary stenting.

DESIGN

A single centre observational study encompassing 1000 consecutive patients with a first stent implantation (1560 stents) between 1986 and 1996, who were followed for at least one year with a median follow up of 29 months (range 12-132 months).

RESULTS

Up to July 1997 the cumulative incidence of the major adverse cardiac events (MACE) of death, non-fatal acute myocardial infarction, coronary artery bypass grafting, and repeat percutaneous transluminal coronary angioplasty was 8.2%, 12.8%, 13.1%, and 22.4%, respectively. Survival at one, three, and five years was 95%, 91%, and 86%, respectively. Comparison of MACE incidence during the "anticoagulant era" and the "ticlopidine era" revealed significantly improved event free survival with ticlopidine (27% v 13%; p < 0.005). Multivariable analyses showed that ejection fraction < 50% (relative risk (RR) 4. 1), multivessel disease (RR 3.0), diabetes (RR 2.9), implantation in saphenous vein graft (RR 2.1), indication for unstable angina (RR 1. 9), and female sex (RR 1.7) were independent predictors of increased mortality after stenting. Independent predictors of any MACE were multivessel stenting (RR 2.0), implantation in saphenous bypass graft (RR 1.6), diabetes (RR 1.5), anticoagulant treatment (versus ticlopidine and aspirin) (RR 1.5), bailout stenting (RR 1.5), multivessel disease (RR 1.4), and multiple stent implantation (RR 1. 5).

CONCLUSIONS

Long term survival and infarct free survival was good, particularly in non-diabetic men with single vessel disease and good ventricular function, who had a single stent implanted in a native coronary artery. A dramatic improvement was observed in event free survival, both early and late, with the replacement of anticoagulation by ticlopidine. This, of course, cannot be separated from improved stent implantation techniques between 1986 and 1995. Ultimately, almost 40% of the patients experienced an adverse cardiac event (mainly repeat intervention) in the long term. New advances in restenosis treatments and in secondary prevention must be directed at this aspect of patient management after stenting.

Clinical and angiographic outcome after implantation of a home-made stent for complicated coronary angioplasty

To defray the escalating costs of coronary stenting, we handmade a balloon-expandable, stainless steel stent, which after experimental evaluation, was implanted in 156 patients undergoing PTCA complicated by a major dissection. The procedural success rate was 98%. The in-hospital course was characterized by a 1.3% cardiopulmonary mortality and a 4.5% nonfatal myocardial infarction rate, while emergency bypass surgery and early repeat PTCA were necessary in only one patient each (0.6%). Clinical 6-mo follow-up in 150 patients revealed no deaths and no myocardial infarctions, and the event-free survival rate was 82%. Six-month control angiography was performed in 93.3% of eligible patients and revealed a restenosis rate of 20%.

Stenting the stent: alternative strategy for treating in-stent restenosis

Several approaches have been taken to relieve restenosis inside a vascular stent. In a patient with a complicated history of coronary artery disease, a restenotic lesion inside a Gianturco-Roubin flex stent was relieved by angioplasty and deployment of three 10 mm Palmaz P-104 "biliary" stents, with urokinase and verapamil used to prevent thromboembolism and the no-reflow phenomenon. An angiographic study 6 months later showed a patient graft with no residual stenosis.

Coronary artery stenting: indications and cost implications

The practice of coronary stenting is evolving rapidly, with new stent designs, deployment techniques, and adjunctive therapy. In many respects, clinical practice is changing in advance of the availability of supporting data. The consistent excellent angiographic result with stent deployment exceeds that achieved by any other previous interventional device, and the extent to which this accounts for the exponential increase in stent utilization cannot be accurately determined but is undoubtedly considerable. Controlled randomized trials have confirmed that stent deployment is superior to balloon angioplasty in certain lesion subsets or clinical scenarios. These include focal de novo native vessel lesions, lesions with late recoil after balloon angioplasty, acute closure after balloon angioplasty, and proximal left anterior descending coronary artery lesions. In addition, observational data is persuasive in focal coronary saphenous vein graft lesions and aorto-ostial lesions. On the other hand, the evidence supporting the use of stents strictly to improve on a suboptimal result, possibly the most frequent indication, is indirect and circumstantial. Stents are expensive, but it was anticipated that with the reduction in restenosis not only would they be cost-effective but also ultimately would reduce costs. This hope has not as yet been realized. However, there is little question that the introduction of intracoronary stents has been the most significant and exciting development since the introduction of percutaneous revascularization almost 20 years ago. It has revitalized the field.

Stents for intracoronary placement: current status and future directions

The technique of intracoronary stenting has achieved remarkable progress over the last few years. Improved stent deployment techniques and optimization of postprocedural management have dramatically improved the safety of intracoronary stent placement. At present, the incidence of early vessel closure after stenting is even lower than that after standard angioplasty and, as most operators no longer prescribe aggressive anticoagulation, bleeding complications are uncommon. Stenting has become an extremely effective treatment for abrupt or threatened vessel closure or for any suboptimal angiographic result during conventional angioplasty. Furthermore, large prospective trials have demonstrated that its efficacy is superior to that of conventional angioplasty for primary restenosis prevention in focal lesions of some native coronary arteries. Ongoing trials tend to extrapolate these conclusions to saphenous vein graft lesions. Mechanical support of the vessel wall explains the sustained angiographic benefit observed after stenting. Future developments may include the use of stents as a vehicle for local drug delivery in an attempt to further reduce the incidence of restenosis. In view of these results, coronary stents should be considered a new standard therapeutic modality in interventional cardiology.

The stenotic stent: mechanisms and revascularization options

As demonstrated by the two recent randomized studies of elective, single stent placement versus balloon angioplasty of de novo lesions in the coronary arteries, angiographic restenosis occurs significantly less after stent implantation. However, reported stent restenosis rate varies from 14% to more than 60%, depending on patient characteristics, stent design, number of stents implanted, vessel treated, location of the lesion, and acute luminal gain. The lowest rate of stenosis occurs in de novo lesions. The highest rate of stent restenosis is encountered in multiple stents and in ostial saphenous vein graft lesions. Stent restenosis can be treated with balloon angioplasty with very high success rates. This treatment is associated with remarkably low incidence of complications. Focal stenoses within the stent are more easily treated than are diffuse occlusions. Atherectomy of intrastent stenosis is not recommended. Excimer and holmium: YAG lasers can be applied for revascularization of intrastent lesions considered "not ideal" for balloon angioplasty. Unless thrombus is present or significant dissection detected or angioplasty performed within 2 months following stenting, patients do not require anticoagulants following balloon angioplasty of stent restenosis.

Comparison of the thrombogenicity of stainless steel and tantalum coronary stents

This study was designed to compare the thrombogenicity of stainless steel and tantalum coronary stents of the same design. Stainless steel and tantalum coronary stents are being evaluated for their utility in treating acute closure and restenosis. A major disadvantage of stainless steel stents is radiolucency. To determine whether radioopaque tantalum stents may be safely substituted for stainless steel stents, we compared the relative thrombogenicity of these materials in stents of identical design. Total platelet and fibrin deposition on the stents were determined from measurements of indium 111-labeled platelet and iodine 125-labeled fibrinogen accumulation after deployment into exteriorized chronic arteriovenous shunts in seven untreated baboons. In another series of experiments, 111In-platelet deposition was compared 2 hours after stent implantation in coronary arteries of pigs. In baboons, platelet thrombus formation on stainless steel and tantalum stents was equivalent and plateaued at approximately 2.5 x 10(9) platelets after 1 hour (p > 0.05). Fibrin deposition averaged approximately 1 mg/stent and did not differ between the stainless steel and tantalum stents (p > 0.05). In the porcine coronary model there was no significant difference in 111In-labeled platelet deposition between the stainless steel and tantalum stents (p > 0.05). This result was confirmed by scanning electron microscopic analysis of the coronary stents. Based on these two models, we conclude that there is no significant difference in the thrombogenicity of stainless steel and tantalum wire coil stents.

Four-year experience with Palmaz-Schatz stenting in coronary angioplasty complicated by dissection with threatened or present vessel closure

BACKGROUND

Abrupt vessel closure after percutaneous transluminal coronary angioplasty (PTCA) is associated with major adverse events. Different surgical and nonsurgical approaches have been advocated to treat or prevent this complication. This study summarizes our 4-year experience with Palmaz-Schatz stenting for the management of 339 patients with present or threatened occlusion after PTCA.

METHODS AND RESULTS

Stent implantation was attempted in a total of 339 and 4959 patients with PTCA during the study period and was successful in 327 (96.5%). During the follow-up, events like death, myocardial infarction, need for revascularization (bypass surgery and repeat in-stent angioplasty), and major vascular complications were recorded. Angiographic follow-up at 6 months was performed in 89.3% of the eligible patients. As part of an initial policy, stenting was intended as a bridge to nonemergency bypass surgery in 26 patients. In 301 patients for whom stenting was intended as permanent treatment, early clinical course (first 4 weeks) was characterized by a 1.3% cardiac mortality and a 4.0% nonfatal myocardial infarction rate; bypass surgery was necessary in 1%, and 6.3% required early repeat PTCA. Surgical repair for peripheral vascular complications was required in 5.6%, and major bleeding events were encountered in 9%. The incidence of subacute stent closure was 6.9%, with subsequent recanalization successful in 86%; subacute stent closure was predicted by presence of vessel occlusion before stenting and localization of the stent in a vessel other than the right coronary artery. Survival rate at 2 years was 95.4%, survival without myocardial infarction was 91.1%, and event-free survival was 70.7%. Survival at 2 years was lower for patients with stents in bypass vein grafts and with myocardial infarction after stenting. Six-month control angiography revealed a restenosis rate of 29.6%.

CONCLUSIONS

Patients with present or threatened occlusion after PTCA may benefit from Palmaz-Schatz stenting. It is associated with a low mortality and myocardial infarction rate and with a long-term event-free rate comparable to that of uncomplicated PTCA.

Self expanding stents in congenital heart disease

OBJECTIVES

To show potential indications for and clinical use of self expanding stents in patients with congenital heart disease.

DESIGN

Descriptive study of selected, non-randomised patients with balloon expandable but persistent stenoses in whom the use of a balloon expandable stent was considered suboptimal or impossible.

SETTING

A tertiary referral centre.

PATIENTS

10 patients, aged 15 days to 32 years. Six patients after atriopulmonary or cavopulmonary anastomosis, two with pulmonary atresia and multiple aortopulmonary collaterals, one with coarctation of the aorta, and one with congenital pulmonary venous stenosis.

RESULTS

Successful, uncomplicated, placement of 10 stents with the desired haemodynamic results, even in tortuous vessels with many stenoses.

CONCLUSIONS

Self expanding stents have a role in the treatment of patients with congenital heart disease. They should be considered when a smaller delivery system and flexibility would aid placement, or in the treatment of long or multiple sequential stenoses.

Self expanding stents for the management of aorto-ostial stenoses in saphenous vein bypass grafts

OBJECTIVE

To assess the early and follow up results of implantation of a self expanding stent in aorto-ostial stenoses of vein grafts.

DESIGN

Prospective, non-randomised, observational study.

SETTING

Tertiary referral centre for cardiac diseases.

PATIENTS

Nineteen patients with ostial stenoses of saphenous vein grafts.

MAIN OUTCOME MEASURES AND RESULTS

Stents were successfully deployed in all 19 patients with satisfactory angiographic results. In one patient this required two attempts. There were no deaths and no major procedural complications related to ostial stenting. Before discharge two (11%) patients had thrombosis of the ostial stent; one patient had a Q wave myocardial infarction. Femoral artery bleeding occurred in three (16%) patients. Angiographic follow up was performed in 18 patients at a mean of seven months. Restenosis within the ostial stent was detected in three (16%) patients. Twelve (63%) patients had an improved functional status at a mean follow up of nine months. One patient died suddenly at three months. Three (16%) patients required additional revascularisation procedures because of symptoms caused by restenosis within the ostial stent during follow up.

CONCLUSIONS

Intracoronary stenting is an attractive treatment for the management of patients with vein graft ostial stenoses.

Balloon angioplasty for treatment of in-stent restenosis: feasibility, safety, and efficacy

Sixty patients with 1 or 2 stainless steel intracoronary stents (Cook, Inc.) underwent balloon angioplasty for in-stent restenosis 1.5-13.5 months after stenting. Seventy-five in-stent redilatation procedures were performed. Seventy-three restenotic lesions (97%) were successfully recrossed and dilated, reducing the mean pre-angioplasty intrastent diameter stenosis from 77 +/- 12% to 20 +/- 11% residual. Although one angioplasty (1.3%) was complicated by non-Q-wave infarction, no angioplasty-related death, acute closure, need for additional stenting, emergent coronary bypass surgery, side branch occlusion, or vascular sequelae occurred. Post-procedure heparin was not used in 83% of successful cases. Most patients were discharged the day following redilatation (mean in-hospital stay 1.7 +/- 1.3 days). At 5.4 +/- 3.4 months following in-stent angioplasty, 84% of patients were in Canadian Cardiovascular Society class 0 or I. In conclusion, balloon dilatation in this stent for restenosis appears simple and efficacious in the short term, and may entail less risk than dilatation of unprotected coronary vessels.

Stent shortening and elongation: pitfalls with the Wiktor coronary endoprosthesis

This report demonstrates two specific complications that occurred during implantation of a Wiktor (Medtronic, Inc., Minneapolis, MN) coronary stent: stent shortening and elongation were observed and attributed to the unique coil structure of the device. Major cardiac events occurred during follow-up as a consequence of this stent deformation. Therefore, semiurgent bypass surgery should be considered to treat this complication.

Comparison of results of intracoronary stenting in patients with unstable vs. stable angina

Percutaneous transluminal coronary angioplasty (PTCA) has higher complication and restenosis rates when performed in the setting of unstable angina. Balloon-expandable intracoronary stenting is a new technique with the potential to improve the results of PTCA. In order to determine whether stenting is associated with a poorer outcome in patients with unstable angina, we retrospectively examined our experience with the Palmaz-Schatz balloon-expandable intracoronary stent in 105 patients. Patients were divided into 2 groups on the basis of symptoms at the time of stent insertion: group I (n = 57) had stable angina pectoris, and group II (n = 48) had unstable angina defined as pain at rest despite antianginal therapy (Braunwald class II, III). Initial (30-d) and final (6-mo) success rates were defined as stent insertion without myocardial infarction, need for bypass surgery, death, and significant angina. Baseline characteristics were similar, although the patients with unstable symptoms were older, more likely to be female, and had a higher incidence of postinfarction angina. A total of 136 stents were successfully delivered to 97 target sites in 92% of patients. Major complications occurred in 4 patients (4%) and were due to subacute thrombosis in 3 of them. There were no differences in complication rates between patients receiving stents electively with stable vs. unstable symptoms (2% vs. 6%, p = NS). Six-mo. follow-up status was ascertained in 96% of patients and revealed overall clinical success in 83% with angiographic restenosis (> or = 50% stenosis) in 28% of patients. There were no significant differences between groups in rates of restenosis, follow-up angina class, or overall clinical success.(ABSTRACT TRUNCATED AT 250 WORDS)

Complications and follow-up after intracoronary stenting: critical analysis of a 6-year single-center experience

From April 1986 through April 1992, 123 patients received 153 intracoronary stents (131 Medinvent, 13 Palmaz-Schatz, 9 Wiktor) during 131 procedures. The indication was bail-out treatment in 39, restenosis in 59 native coronary arteries, and stenosis or restenosis in 33 vein grafts. Stent-related events were studied during the in-hospital stay and on follow-up and included closure, stent restenosis, myocardial infarction, death, and the need for coronary bypass surgery. A Kaplan-Meier estimate extended to 6 years showed different short- and long-term outcomes for the distinct treatment groups (p < 0.05): right coronary artery stenting (more particularly, stenting for restenosis after angioplasty) had the lowest and vein graft stenting had the highest stent-related complication rate. The complication rate was similar (p > 0.25) (1) in the case of multiple nontandem stent implantation during the same procedure; (2) for the different endoprosthesis sizes; and (3) during the different procedural years. In native coronary arteries, restenosis after angioplasty of the right coronary artery could be a preferential indication for coronary artery stenting. Despite a favorable short-term outcome, vein graft stenting has a high incidence of events on long-term follow-up, mainly because of late restenosis. Multiple nontandem stenting during the same procedure is not associated with a higher incidence of complications, in particular, the restenosis rate is not appreciably higher. Finally, only a minor benefit for the learning curve is apparent from this single-center experience with continual unchanged postprocedural management.

Brachial approach for intracoronary stent implantation: a feasibility study

Implantation of coronary artery stents via the percutaneous femoral approach is associated with a high rate of vascular complications at the access site related to the size of the entry hole and the intense anticoagulation required to prevent stent thrombosis. Therefore we studied the feasibility of using the left brachial approach utilizing open arterial repair for implantation of coronary artery stents. Intracoronary stent implantation via the femoral approach in 24 patients (group A) was compared with implantation via the brachial approach in 16 patients (group B). Baseline lesion characteristics were similar in the two groups. All stents in group A (n = 27 stents) were successfully delivered to their target vessel. One stent in group B (n = 18 stents) could not be delivered because of an inability to engage the coronary artery from the brachial approach. There were no significant differences in the angiographic outcome between the two groups. Complications including hematomas, hemorrhage requiring blood transfusion, vascular injury requiring surgery, and pseudoaneurysm formation were significantly more common in group A than in group B (8/24 [33%] versus 1/16 [6%], respectively; p < 0.05). In addition, the length of hospital stay was significantly longer for the femoral approach than the brachial approach (9.4 vs 6.5 days, respectively; p < 0.05). Thus the left brachial approach for intracoronary stent implantation is technically feasible, safe, and associated with fewer local vascular complications and a shorter hospitalization than the femoral approach.

Endovascular stents: preliminary clinical results and future developments

At present, there is an exponential use of new interventional techniques whose proper role and value have not yet been defined. The intracoronary stent is just one example. There is no doubt that stents can be implanted with a high technical success rate associated with highly predictable immediate angiographic results and that they appear to be superior to all other interventional techniques. However, the intrinsic thrombogenicity of all devices currently available for clinical use warrants a vigorous anticoagulation, exposing the patient either to the risk of (sub)acute stent thrombosis or to the risk of hemorrhage and vascular complications. It remains to be determined whether stent implantation will reduce the incidence of restenosis and whether this results in an improved long-term event and symptom-free survival. Experimental studies indicate that the thrombogenic nature of stents may be controlled by coating the struts with endothelial cells or polymers. With respect to restenosis, it is evident that as long as mechanical injury is applied to the vessel wall, the vessel wall will respond with neointimal thickening. The intracoronary stent has the potential to control this tissue response by serving as a carrier for local antiproliferative drug delivery or eventually for genetic manipulation. The intensive research which is now going on in combination with experimental animal data, human postmortem pathologic observations, and angiographic studies is yielding clear insights and future directions to address these issues.

Thrombosis of a flexible coil coronary stent: frequency, predictors and clinical outcome

OBJECTIVES

The aim of this study was to evaluate the predictors and clinical sequelae of stent thrombosis.

BACKGROUND

Although coronary artery stenting is being increasingly applied, the major unique complication of stent thrombosis is not well characterized.

METHODS

We studied 145 patients who underwent coronary artery stenting with the Gianturco-Roubin flexible coil design for abrupt vessel closure or to prevent restenosis. There were 17 stented vessel closures (11.7%), 7 as a result of acute (< 24 h) and 10 of subacute (days 1 to 21) thrombosis.

RESULTS

In seven patients successful coronary recanalization was achieved with thrombolytic agents and balloon angioplasty. Creatine kinase was significantly elevated in 13 patients, with a Q wave myocardial infarction in 11 and emergency coronary artery bypass grafting in 8. Comparisons (multivariate analysis) with a control cohort (n = 33) of patients without thrombosis matched for age, gender and vessel stented revealed lesion eccentricity (p = 0.003), unstable angina (p = 0.048) and indication for stent implantation (abrupt closure versus restenosis) (p = 0.002), as predictors of thrombotic occlusion of stented vessels. Subtherapeutic anticoagulation (activated partial thromboplastin time < 2 times control value, prothrombin time < 1.4 control value) occurred at least once during the hospital stay in all 10 patients with subacute thrombosis and in 20 of 33 control patients (p = 0.047). In 2 patients with subacute thrombosis and 11 control subjects, subtherapeutic anticoagulation was necessitated by bleeding.

CONCLUSIONS

Early thrombosis after coronary stenting was relatively common (> 10%), occurring predominantly in eccentric lesions and in patients with unstable angina pectoris. This complication is associated with significant adverse clinical outcomes and may be reduced by more intensive anticoagulation yet, in a delicate balance, can be precipitated by inadequate heparin therapy.

Assessment of coronary stent by intravascular ultrasound

The use of intravascular ultrasound to assess the adequacy of the deployment of an intracoronary stent is described. Although angiographically a good result was suggested, intravascular ultrasound showed this to be misleading.

Long-term clinical and angiographic follow-up of patients treated with the self-expanding coronary stent for acute occlusion during balloon angioplasty of the right coronary artery

A self-expanding coronary stent was implanted in 17 patients to treat acute occlusion of the right coronary artery after percutaneous transluminal angioplasty. There were 2 women and 15 men, with a mean age of 59 +/- 8 years. All patients underwent at least one follow-up angiographic examination 4 to 6 months after implantation and six patients had additional follow-up angiography. During a mean follow-up interval of 32 +/- 10 months no patient died or had a myocardial infarction. Restenosis within the stent did not occur. Two patients had a new stenosis adjacent to the stent. Stent occlusion was found on follow-up angiography in one patient who had not been treated with an antiplatelet agent. The mean intraluminal diameter was 2.77 +/- 0.5 mm after implantation and 2.67 +/- 0.5 mm on follow-up angiography. It is concluded that coronary stenting is effective in treating right coronary artery occlusion after balloon angioplasty. Immediate and long-term outcome suggest that the right coronary artery may be a particularly favorable site for stent implantation.

Stenting of venous bypass grafts: a new treatment modality for patients who are poor candidates for reintervention

During a 2-year period, 136 self-expanding Wallstents were implanted in saphenous vein bypass grafts in 69 patients with end-stage coronary artery disease. All patients had severe symptoms and the majority were poor candidates for either repeat surgery or conventional bypass coronary angioplasty because of unfavorable native anatomy, impaired left ventricular function, or a high-risk bypass lesion anatomy for coronary angioplasty. All procedures were technically successful without major complications and a need for emergency bypass surgery. However, during the hospital stay acute thrombotic complications occurred in seven patients (10%) resulting in one death and acute myocardial infarction in five patients and necessitating emergency repeat PTCA in two patients and repeat CABG in four. Twenty-three patients had serious hemorrhagic complications directly related to the rigorous anticoagulation schedule. Two patients died of fatal cerebral bleeding. During follow-up, another five patients died accounting for a total mortality rate of 12%. At late angiographic follow-up (4.9 +/- 3.4 months, n = 53), 25 patients (47%) had a restenosis (greater than or equal to 50% DS) within or immediately adjacent to the stent, necessitating reintervention in 19 patients (PTCA, n = 12; repeat CABG, n = 7). In the group without stent-related restenosis (n = 28), 15 patients had progression of disease in either the native or bypass vessels leading to recurrence of major anginal symptoms within 1 to 24 months. Ten of these patients required further intervention (stent, n = 6; PTCA, n = 3; repeat CABG, n = 1). Stenting in saphenous coronary bypass grafts can be performed safely with excellent immediate angiographic and clinical results.(ABSTRACT TRUNCATED AT 250 WORDS)