Stenting for coronary dissection after balloon dilation of in-stent restenosis: stenting a previously stented site

Current Role of Laser Angioplasty of Restenotic Coronary Stents

Treatment of in-stent restenosis (ISR) with conventional percutaneous transluminal coronary angioplasty (PTCA) causes significant recurrent neointimal tissue growth in 30-85%. Therefore, laser ablation of intrastent neointimal hyperplasia before balloon dilation can be an attractive alternative. However, the long-term outcomes of such treatment have not been studied thoroughly enough. This prospective case-control study evaluated angiographic and clinical outcomes of PTCA alone and a combination of excimer laser coronary angioplasty (ELCA) and adjunct PTCA in 125 patients with ISR. ELCA was performed before balloon dilation in 67 patients, PTCA alone was performed in 58 patients. Basic demographic and clinical data were comparable in both groups. Lesions included in ELCA group were longer (17.1 ±9.9 vs 13.6 ±9.1 mm; p=0.034), more complex (36.5% type C stenoses vs 14.3%; p=0.006), and more frequently had reduced distal blood flow (TIMI <3: 18.9% vs 4.8%; p=0.025) compared to lesions in the PTCA group. Immediate angiographic results of PTCA and ELCA + PTCA appeared to be comparable. PTCA alone was successful in 57 patients (98.3%), ELCA + PTCA, in 66 patients (98.5%). The rates of hospital complications were comparable (3.0% in ELCA group vs 8.6% in PTCA group). The 1-year follow-up showed that the rates of major adverse cardiac events (MACE) were comparable in the 2 groups (37.3% in ELCA group vs 46.6% in PTCA group). The rates of target vessel revascularization (TVR) within 1 year after the intervention were also similar in the 2 groups (32.8% vs 34.5%). The data mean that ELCA in patients with complex ISR is efficient and safe. Despite a higher complexity of lesions in the ELCA group, no increase in the rate of complications was registered.

Current treatment of in-stent restenosis

Management of patients with in-stent restenosis (ISR) remains an important clinical problem. Although drug-eluting stents (DES) have drastically reduced the incidence of ISR, treatment of DES-ISR is particularly challenging. ISR mainly results from aggressive neointimal proliferation, but recent data also suggest that neoatherosclerosis may play an important pathophysiological role. Intracoronary imaging provides unique insights to unravel the underlying substrate of ISR and may be used to guide repeated interventions. In this paper, we systematically reviewed clinical trial data with currently available therapeutic modalities, including DES and drug-coated balloons, in patients presenting with ISR within bare-metal stents or DES.

A randomized comparison of repeat stenting with balloon angioplasty in patients with in-stent restenosis

OBJECTIVES

This randomized trial compared repeat stenting with balloon angioplasty (BA) in patients with in-stent restenosis (ISR).

BACKGROUND

Stent restenosis constitutes a therapeutic challenge. Repeat coronary interventions are currently used in this setting, but the recurrence risk remains high.

METHODS

We randomly assigned 450 patients with ISR to elective stent implantation (224 patients) or conventional BA (226 patients). Primary end point was recurrent restenosis rate at six months. Secondary end points included minimal lumen diameter (MLD), prespecified subgroup analyses, and a composite of major adverse events.

RESULTS

Procedural success was similar in both groups, but in-hospital complications were more frequent in the balloon group. After the procedure MLD was larger in the stent group (2.77 +/- 0.4 vs. 2.25 +/- 0.5 mm, p < 0.001). At follow-up, MLD was larger after stenting when the in-lesion site was considered (1.69 +/- 0.8 vs. 1.54 +/- 0.7 mm, p = 0.046). However, the binary restenosis rate (38% stent group, 39% balloon group) was similar with the two strategies. One-year event-free survival (follow-up 100%) was also similar in both groups (77% stent vs. 71% balloon, p = 0.19). Nevertheless, in the prespecified subgroup of patients with large vessels (> or =3 mm) the restenosis rate (27% vs. 49%, p = 0.007) and the event-free survival (84% vs. 62%, p = 0.002) were better after repeat stenting.

CONCLUSIONS

In patients with ISR, repeat coronary stenting provided better initial angiographic results but failed to improve restenosis rate and clinical outcome when compared with BA. However, in patients with large vessels coronary stenting improved the long-term clinical and angiographic outcome.

Clinical and angiographic outcome in the laser angioplasty for restenotic stents (LARS) multicenter registry

In-stent restenosis (ISR), when treated with balloon angioplasty (PTCA) alone, has an angiographic recurrence rate of 30%-85%. Ablating the hypertrophic neointimal tissue prior to PTCA is an attractive alternative, yet the late outcomes of such treatment have not been fully determined. This multicenter case control study assessed the angiographic and clinical outcomes of 157 consecutive procedures in 146 patients with ISR at nine institutions treated with either PTCA alone (n = 64) or excimer laser assisted coronary angioplasty (ELCA, n = 93)) for ISR. Demographics were similar except more unstable angina at presentation in ELCA-treated patients (74.5% vs. 63.5%; P = 0.141). Lesions selected for ELCA were longer (16.8 +/- 11.2 mm vs. 11.2 +/- 8.6 mm; P < 0.001), more complex (ACC/AHA type C: 35.1% vs. 13.6%; P < 0.001), and with compromised antegrade flow (TIMI flow < 3: 18.9% vs. 4.5%; P = 0.008) compared to PTCA-treated patients. ELCA-treated patients had similar rate of procedural success [93 (98.9% vs. 62 (98.4%); P = 1.0] and major clinical complications [1 (1.1%) vs. 1 (1.6%); P = 1.0]. At 30 days, repeat target site coronary intervention was lower in ELCA-treated patients (1.1% vs. 6.4% in PTCA-treated patients; P = 0.158), but not significantly so. At 1 year, ELCA-treated patients had similar rate of major cardiac events (39.1% vs. 45.2%; P = 0.456) and target lesion revascularization (30.0% vs. 32.3%; P = 0.646). These data suggest that ELCA in patients with complex in-stent restenosis is as safe and effective as balloon angioplasty alone. Despite higher lesion complexity in ELCA-treated patients, no increase in event rates was observed. Future studies should evaluate the relative benefit of ELCA over PTCA alone for the prevention of symptom recurrence specifically in patients with complex in-stent restenosis.

Stenting the stent: initial results and long-term clinical and angiographic outcome of coronary stenting for patients with in-stent restenosis

Stent restenosis constitutes a therapeutic challenge affecting an increasing number of patients. Conventional angioplasty and debulking techniques are currently used in these patients. However, the potential role of a second stent implantation in this setting (stenting the stent) remains unknown. Therefore, 65 consecutive patients (12 women, aged 62 +/- 11 years) undergoing stent implantation (42 elective and 23 unplanned) for the treatment of in-stent restenosis (diffuse [> 10 mm] in 39 [60%]) were studied. Angiographic success was obtained in all patients. Three patients developed hospital complications: 1 died from refractory heart failure and 2 suffered non-Q-wave myocardial infarctions. During follow-up (mean 17 +/- 11 months) 1 patient died (noncardiac cause) and only 9 (14%) required target vessel revascularization. Kaplan-Meier event-free survival (freedom from death, myocardial infarction, and target vessel revascularization) at 1 year was 84%. Using Cox analysis, patients with unstable symptoms, a short time to stent restenosis, nonelective stenting, and B2-C lesions tended to have poorer prognosis. After adjustment, nonelective stenting was associated (adjusted RR 2.9, 95% confidence interval [CI] 0.82 to 10.3, p = 0.09) with an adverse clinical outcome. On quantitative angiography (core lab) restenosis was found in 13 of 43 patients (30%) (75% of those eligible). Logistic regression analysis identify restenosis length (adjusted RR 1.43, 95% CI 1.04 to 2.14, p = 0.04), and time to restenosis (adjusted RR 0.67, 95% CI 0.47 to 0.94, p = 0.01) as the only independent predictors of recurrent restenosis. Thus, repeat coronary stenting is a safe and efficacious strategy for the treatment of patients with in-stent restenosis. Both elective and nonelective stenting provide excellent initial results. The long-term clinical and angiographic outcome of these patients is also favorable.

Clinical and angiographic follow-up after balloon angioplasty with provisional stenting for coronary in-stent restenosis

The objective of this study was to assess the angiographic and clinical outcome of patients with coronary in-stent restenosis treated with balloon angioplasty with provisional stenting. The study included 375 consecutive patients with in-stent restenosis managed with balloon angioplasty alone or combined with stenting. Clinical events were recorded during a 1-year follow-up period and quantitative analysis was performed on 6-month angiographic data. Of the 373 patients (451 lesions) with a successful procedure, 273 were treated with angioplasty alone and 100 with additional stenting. Target lesion revascularization was required in 23.7% of the patients: 20.7% in patients with angioplasty and 31.0% in patients with stenting. Angiographic restenosis rate was 38.9%: 35.8% in the angioplasty group and 47.7% in the stent group. Stenting in small vessels was associated with a much higher restenosis rate than in larger vessels (65.6% vs. 37.5%, respectively; P = 0.01). Thus, repeat balloon angioplasty with provisional stenting for in-stent restenosis is a safe treatment strategy associated with a relatively favorable long-term outcome. However, the long-term results might be improved if additional stenting is avoided especially in small vessels. Cathet. Cardiovasc. Intervent. 48:151-156, 1999.

[Stent restenosis: therapy concepts and possibilities for prevention]

BACKGROUND

In-stent restenosis has become a significant problem for interventional cardiologists. Due to different pathogenic causes it remains unclear whether a uniform therapeutic regimen is appropriate.

TREATMENT

Redilatation has predominantly been used for the treatment of instent restenosis, however, in long and diffuse restenotic stents, long-term results are reported to be poor. Therefore, tissue-debulking techniques may have beneficial effects in complex cases of in-stent restenosis. The therapeutic benefit of intracoronary radiation, local drug delivery or gene transfer has not been evaluated so far.

PREVENTION

Therefore, prevention of the iatrogenic entity in-stent restenosis has become more important.

[Pathophysiology and therapeutic concepts in coronary restenosis]

Demonstration of a reduced restenosis rate after stent implantation (Benestent, STRESS) has initiated rapid increase in stent implantation rates with widening indications. At present, the majority of stents are implanted in "none-Benestent/STRESS-lesions" with the consequence of a higher restenosis rate as previously expected. Stent restenosis has therefore become a relevant problem in interventional cardiology. In contrast to balloon angioplasty, where acute and subacute recoil represents the major mechanism of restenosis, stent restenosis is exclusively attributed to neointima proliferation. Morphological studies have demonstrated that neointima is caused by early smooth muscle cell ingrowth with a maximum after 7 days which is then gradually replaced by extracellular matrix. Systematic clinical, angiographic and intravascular ultrasound studies have identified several risk factors for increased stent restenosis such as: diabetes mellitus, treatment of restenosis, serial stent implantation, small and calcified vessels, ostial lesions, venous bypass grafts and complex stenosis morphology. In addition, there is increasing evidence that aggressive implantation techniques with high pressures and oversized balloons may also induce higher restenosis rates. Optimal treatment of instent restenosis has not been determined so far. Balloon angioplasty is at present considered the therapeutic option of choice. Several small studies have shown, that in short, discrete lesions (< 10 mm) results of simple PTCA are acceptable with re-restenosis rates between 15 and 35%. The intervention is considered safe with low complication rates. In 10 to 15% additional stent implantation is necessary, usually due to dissections proximal or distal to the treated stent. In long, diffuse stent restenosis (> or = 10 mm), however, PTCA results in high re-restenosis rates up to > 80%. This is most likely due to insufficient early balloon angioplasty results with minimal luminal diameters (MLD) significantly below the previous stent diameter. Therefore, debulking techniques have been used to reduce neointima burden within the stent. At present 3 techniques are available: directional coronary atherectomy (DCA), Excimerlaser angioplasty (ELCA) or high frequency rotablation. All of these techniques achieve a significant reduction in plaque volume within the stent and in combination with balloon angioplasty allow larger MLDs than PTCA alone. Limited experiences with ELCA and rotablation have shown that the techniques are safe without major periinterventional complications. DCA, however, has been accompanied with stent destruction and therefore should be considered with large care, especially in stents with coil design. At present, no randomized controlled trials for the comparison of debulking techniques with or without balloon angioplasty versus balloon angioplasty alone are available. Three multicenter trials have been initiated (LARS, ARTIST and TWISTER) to compare debulking techniques versus balloon angioplasty in diffuse stent restenosis. Adjunct medical treatment after interventions for stent restenosis is usually limited to ASS alone, indications for additional application of Ticlopidine have not been verified so far. Positive results are expected for the use of local radiation therapy either by radioactive stent implantation or afterloading techniques. With increasing stent implantation rates and indications, about 400,000 stents will be implanted in 1997 worldwide. Considering a low restenosis rate of 20%, 80,000 stent restenosis will occur within one year. Final recommendations for optimal treatment of these patients are not yet available.

Arterial perforation during optimization of coronary stents using high-pressure balloon inflations

Angiographic optimization of coronary stents, using high-pressure balloon inflation, was complicated by vessel rupture in 3 patients. The risk of this potentially life-threatening complication should be considered during stent optimization.