Coronary artery stent restenosis responds favorably to repeat interventions

Drug-eluting stents: new era and new concerns

At present there is much excitement about drug-eluting stents, which hold promise for the treatment of coronary artery disease. This ingenious therapy involves coating the outside of a standard coronary stent with a thin polymer containing medication that can prevent scarring at the site of coronary intervention. Early trials with sirolimus coated stents showed that they might prevent coronary artery restenosis, but later studies, involving more complex coronary lesions, did not show a complete absence of restenosis. Recent studies have demonstrated the long term cost effectiveness of drug-eluting stents as they have reduced the need for revascularisation procedures. At present there are few data on the safety and effectiveness of stents over follow up periods exceeding two years, and data obtained from animal models of stenting might not be completely applicable to humans. There are concerns that drug-eluting stents might delay, rather than inhibit, restenosis. Also there is concern regarding the inflammation caused by the polymer substrate. This article reviews the present data on drug-eluting stents and their benefits, shortcomings, and concerns.

Cutting balloon versus conventional balloon angioplasty for the treatment of in-stent restenosis: results of the restenosis cutting balloon evaluation trial (RESCUT)

OBJECTIVES

The aim of this trial was to compare cutting balloon angioplasty (CBA) with conventional balloon angioplasty (i.e., percutaneous transluminal coronary angioplasty [PTCA]) for the treatment of patients with coronary in-stent restenosis (ISR).

BACKGROUND

Retrospective studies suggest CBA might be superior to conventional PTCA in the treatment of ISR.

METHODS

The Restenosis Cutting Balloon Evaluation Trial (RESCUT) is a multicenter, randomized, prospective European trial including 428 patients with all types of ISR (e.g., focal, multifocal, diffuse, proliferative).

RESULTS

In both groups, the majority of ISR lesions were shorter than 20 mm. The length of restenotic stents was similar (CBA: 18.6 +/- 9.7 mm; PTCA: 18.3 +/- 8.7 mm). The number of balloons used to treat ISR was lower in the CBA group: only one balloon was used in 82.3% of CBA cases, compared with 75% of PTCA procedures (p = 0.03). Balloon slippage was less frequent in the CBA group (CBA 6.5%, PTCA 25%; p < 0.01). There was a trend toward a lower need for additional stenting in the CBA group (CBA 3.9%, PTCA 8.0%; p = 0.07). At seven-month angiographic follow-up, the binary restenosis rate was not different between the groups (CBA 29.8%, PTCA 31.4%; p = 0.82), with a similar pattern of recurrent restenosis. Clinical events at seven months were also similar.

CONCLUSIONS

Cutting balloon angioplasty did not reduce recurrent ISR and major adverse cardiac events, as compared with conventional PTCA. However, CBA was associated with some procedural advantages, such as use of fewer balloons, less requirement for additional stenting, and a lower incidence of balloon slippage.

Abciximab administration and clinical outcomes after percutaneous intervention for in-stent restenosis

Abciximab therapy improves clinical outcomes after percutaneous interventions for de novo coronary artery disease. We sought to determine whether clinical outcomes after percutaneous intervention for in-stent restenosis are affected by abciximab administration. Between January 1996 and July 1999, 322 consecutive patients underwent percutaneous intervention for in-stent restenosis; 157 patients received abciximab and 165 patients were treated without abciximab based on operator discretion. Baseline clinical and angiographic variables and type of percutaneous intervention were recorded. Follow-up information was obtained and clinical endpoints were recorded. A multivariate analysis was performed to determine the independent variables associated with adverse clinical outcomes. Baseline clinical and angiographic variables were similar in both groups. Patients who received abciximab were more likely to be treated with rotational atherectomy and less likely to have only balloon angioplasty or repeat stenting. Mean follow-up duration was 19 +/- 12 months. There were no significant differences in the incidence of angina/myocardial infarction (29% vs. 30%; P = 0.9), target vessel revascularization (18% vs. 21%; P = 0.5), death (8% vs. 7%; P = 0.4), or major adverse cardiovascular events (38% vs. 39%; P = 0.9) in both groups. Abciximab administration was not an independent variable associated with adverse outcomes. In this observational study, clinical outcomes after percutaneous intervention for in-stent restenosis did not seem to be affected by abciximab administration. Randomized trials are needed to identify the role of platelet glycoprotein IIb/IIIa inhibitors in the management of in-stent restenosis.

The initial course of in-stent restenosis influences the response to vascular brachytherapy

BACKGROUND

Vascular brachytherapy (VBT) reduces the rate of recurrence of in-stent restenosis (ISR) by inhibiting intimal proliferation. However, the rate of cell proliferation, reflected by the speed of ISR development, is variable in ISR lesions and might influence the responsiveness of ISR to radiation. The aim of this study was to determine the influence of the initial ISR course on the clinical outcome of patients undergoing VBT.

METHODS

In 1165 patients treated for ISR with VBT in the WRIST studies, we determined the time for ISR (time between initial stent implantation and restenosis), the time for VBT treatment (time between stent implantation and VBT), and previous ISR treatment with conventional strategies. Target lesion revascularization (TLR) at 6 months was available in all patients.

RESULTS

Previous ISR treatment did not influence the result of VBT (TLR was 17% vs. 16% without previous angioplasty). Time to ISR influences the outcome of patients undergoing VBT; TLR decreased when ISR occurred later. TLR was 18.2%, 16.7%, and 11.1% when time to ISR was <90, 90-2700, and >270 days, respectively, P=.03. Early ISR (time for ISR <90 days) is a factor for radiation failure (OR=2.1, P<.05). In patients with early ISR, TLR is lower when VBT is delayed; TLR was 11% if performed 90 days after stent implantation as compared to 22% if VBT is performed early (<90 days), P<.05.

CONCLUSION

The course of ISR development affects the long-term efficacy of VBT. Early restenosis remains a factor of treatment failure in the VBT era. Delaying VBT beyond 90 days after stent implantation reduces the rate of subsequent revascularization in these patients.

Percutaneous and surgical interventions for in-stent restenosis: long-term outcomes and effect of diabetes mellitus

OBJECTIVE

We examined long-term outcomes of patients with in-stent restenosis (ISR) who underwent different percutaneous interventions at the discretion of individual operators: balloon angioplasty (BA), repeat stent or rotational atherectomy (RA). We also examined long-term outcomes of patients with ISR who underwent coronary artery bypass surgery (CABG).

BACKGROUND

In-stent restenosis remains a challenging problem, and its optimal management is still unknown.

METHODS

Symptomatic patients (n = 510) with ISR were identified using cardiac catheterization laboratory data. Management for ISR included BA (169 patients), repeat stenting (117 patients), RA (107 patients) or CABG (117 patients). Clinical outcome events of interest included death, myocardial infarction, target vessel revascularization (TVR) and a combined end point of these major adverse cardiovascular events (MACE). Mean follow-up was 19+/-12 months (range = 6 to 61 months).

RESULTS

Patients with ISR treated with repeat stent had significantly larger average post-procedure minimal lumen diameter compared with BA or RA (3.3+/-0.4 mm vs. 3.0+/-0.4 vs. 2.9+/-0.5, respectively, p < 0.05). Incidence of TVR and MACE were similar in the BA, stent and RA groups (39%, 40%, 33% for TVR and 43%, 40%, 33% for MACE, p = NS). Patients with diabetes who underwent RA had similar outcomes as patients without diabetes, while patients with diabetes who underwent BA or stent had worse outcomes than patients without diabetes. Patients who underwent CABG for ISR, mainly because of the presence of multivessel disease, had significantly better outcomes than any percutaneous treatment (8% for TVR and 23% for MACE).

CONCLUSIONS

In this large cohort of patients with ISR and in the subset of patients without diabetes, long-term outcomes were similar in the BA, repeat stent and RA groups. Tissue debulking with RA yielded better results only in diabetic patients. Bypass surgery for patients with multivessel disease and ISR provided the best outcomes.

[In-hospital major complications associated with rotational atherectomy: experience with 800 patients at a single center]

INTRODUCTION

Rotational atherectomy is usually performed in patients with angiographically determined high risk coronary lesions. The aim of this study was to evaluate the rate of major adverse cardiac events (death, Q-wave infarction or new revascularization) after rotational atherectomy, as well as to identify the clinical characteristics associated with this incidence.

PATIENTS AND METHODS

The study population included 800 patients treated with rotational atherectomy from 1993 to 1999: 512 (64%), for de novo lesions, and 288 (36%) for restenosis. Balloon dilation and coronary stenting was performed in 95% and 34% of patients, respectively.

RESULTS

During hospitalization, 17 patients (2.1%) died, 16 (2%) had a Q-wave infarction, 30 (3.8%) a non-Q infarction, and new revascularization was performed in 28 (3.5%). The incidence of major adverse cardiac events was 6.5% (n = 52), this incidence being higher in the presence of diabetes (8.9 vs. 4.4%; p = 0.01), unstable angina or acute/recent myocardial infarction (7.6 vs. 3.3%; p = 0.02), multivessel disease (8.6 vs. 3.3%; p < 0.01), treated vessel other than right coronary (7.0 vs. 1.7%; p = 0.01), procedure in > 1 vessel (10.7 vs. 4.7%; p < 0.01), angiographic failure (62.5 vs. 5.5%; p < 0.001), and de novo lesions (8.4 vs. 2.5%; p < 0.01), with diabetes and treatment of de novo lesions being independent predictors of major adverse cardiac events. However, age, previous infarction, and left ventricular dysfunction, were not associated with the rate of events.

CONCLUSION

Some simple variables are associated with a higher incidence of major adverse cardiac events after rotational atherectomy. Advanced age, previous infarction and left ventricular dysfunction, however, do not necessarily imply a poorer prognosis in these patients.

Long-term outcome of patients with proximal left anterior descending coronary artery in-stent restenosis treated with rotational atherectomy

Once a first interventional procedure has failed, patients with proximal left anterior descending in-stent restenosis are frequently sent for surgical revascularization. Data on long-term outcome in selected patients with proximal left anterior descending in-stent restenosis treated with RA are lacking. The study's objective was to evaluate the long-term outcome of patients with proximal left anterior descending artery in-stent restenosis treated with rotational atherectomy. The study population is constituted by 42 patients with proximal left anterior descending in-stent restenosis treated with rotational atherectomy. Patients were followed up for 2.1 +/- 0.9 years (range, 6--54). Restenosis length was 16.5 +/- 9.2 mm, and restenosis was diffuse (> 10 mm in length) in 30 (71.4%). The rotational atherectomy procedure was guided by intravascular ultrasound in 18 patients (42.9%). Maximum burr/artery ratio was > 0.7 in 24 (57.1%) patients. One patient suffered a periprocedural non--Q-wave infarction, but no deaths, Q-wave infarction, or new target vessel revascularization occurred during hospitalization. There were no deaths or myocardial infarctions after discharge. Sixteen patients (38.1%) needed a new revascularization, but only five (11.9%) underwent coronary bypass grafting at the end of the follow-up (2.1 +/- 0.9 years). The rate of surgical revascularization at 6 months, 1 year, and 3 years was 4.8%, 7.4%, and 18.4%, respectively. The rate of new target vessel revascularization at 6 months, 1 year, and 3 years was 16.7%, 36.5%, and 40.5%, respectively. Patients with < or = 5 months since stent implantation had a significantly higher rate of new target vessel revascularization. Patients with proximal left anterior descending in-stent restenosis may be safely treated with rotational atherectomy. This strategy is associated with a very good long-term outcome, with few patients undergoing surgical revascularization.

Localized intracoronary gamma-radiation therapy to inhibit the recurrence of restenosis after stenting

BACKGROUND

Although the frequency of restenosis after coronary angioplasty is reduced by stenting, when restenosis develops within a stent, the risk of subsequent restenosis is greater than 50 percent. We report on a multicenter, double-blind, randomized trial of intracoronary radiation therapy for the treatment of in-stent restenosis.

METHODS

Of 252 eligible patients in whom in-stent restenosis had developed, 131 were randomly assigned to receive an indwelling intracoronary ribbon containing a sealed source of iridium-192, and 121 were assigned to receive a similar-appearing nonradioactive ribbon (placebo).

RESULTS

The primary end point, a composite of death, myocardial infarction, and the need for repeated revascularization of the target lesion during nine months of follow-up, occurred in 53 patients assigned to placebo (43.8 percent) and 37 patients assigned to iridium-192 (28.2 percent, P=0.02). However, the reduction in the incidence of major adverse cardiac events was determined solely by a diminished need for revascularization of the target lesion, not by reductions in the incidence of death or myocardial infarction. Late thrombosis occurred in 5.3 percent of the iridium-192 group, as compared with 0.8 percent of the placebo group (P=0.07), resulting in more late myocardial infarctions in the iridium-192 group (9.9 percent vs. 4.1 percent, P=0.09). Late thrombosis occurred in irradiated patients only after the discontinuation of oral antiplatelet therapy (with ticlopidine or clopidogrel) and only in patients who had received new stents at the time of radiation treatment.

CONCLUSIONS

Intracoronary irradiation with iridium-192 resulted in lower rates of clinical and angiographic restenosis, although it was also associated with a higher rate of late thrombosis, resulting in an increased risk of myocardial infarction. If the problem of late thrombosis within the stent can be overcome, intracoronary irradiation with iridium-192 may become a useful approach to the treatment of in-stent restenosis.

Predictors of clinical outcome following percutaneous intervention for in-stent restenosis

Percutaneous intervention for the first episode of in-stent restenosis was performed in 177 patients 5.4 +/- 0.3 months after native coronary stent implantation. Medical records were reviewed and patients contacted 13.3 +/- 1.2 months after in-stent intervention to ascertain the subsequent clinical course. The effects of demographic, procedural, and angiographic variables on clinical outcomes were determined. At 2 years, Kaplan-Meier estimated survival was 93 +/- 3% and freedom from death, myocardial infarction, and a third target artery revascularization (TAR) was 67 +/- 4%. The actuarial frequency of a third TAR was 26 +/- 4% at 1 year. Stratification of outcomes according to timing of in-stent intervention revealed an approximate twofold higher frequency of adverse events among patients with early (</=3 months) in-stent restenosis. Advanced age (p = 0.019), prior coronary bypass (p = 0. 017), and early in-stent intervention (p = 0.006) independently predicted increased mortality at follow-up. Systemic hypertension (p = 0.004), diabetes mellitus (p = 0.044), and early in-stent intervention (p <0.0001) independently predicted a third TAR. These variables (p = 0.007, p = 0.027, and p <0.0001, respectively) also independently predicted a composite end point consisting of death, myocardial infarction, and a third TAR. No angiographic variable predicted outcome after in-stent intervention. Thus, long-term outcome following in-stent intervention was favorable. Early in-stent intervention, advanced age, hypertension, and diabetes predicted adverse outcomes.