Long-term follow-up after deferring angioplasty in asymptomatic patients with moderate noncritical in-stent restenosis

Impact of In-Stent Minimal Lumen Area at 9 Months Poststent Implantation on 3-Year Target Lesion Revascularization–Free Survival

Background— Intravascular ultrasound (IVUS) is used to assess intermediate lesions in native coronary arteries; minimum lumen area (MLA) <4.0 mm 2 is accepted as a cutoff for a significant stenosis. We evaluated the IVUS in-stent MLA at 9-month follow-up that best predicted subsequent target lesion revascularization (TLR)–free survival in patients from the TAXUS IV, V, and VI studies.

Methods and Results— In the combined TAXUS IV, V, and VI randomized trials, 9-month IVUS was available in 635 patients (331 treated with paclitaxel-eluting stents [PES] and 304 treated with bare-metal stents [BMS]) who did not require TLR in the first 9 months postintervention and who were followed for 3 years. The in-stent MLA that best predicted 3-year TLR-free survival was determined. At 9-months follow-up, IVUS-measured in-stent MLA was 5.7�2.3 mm 2 in the PES group and 4.8�2.3 mm 2 in the BMS group. Between 9 months and 3 years, TLR was required in 4.9% of patients who were treated with PES and 6.7% of patients who were treated with BMS. Multivariate analysis identified MLA at 9 months as a significant predictor of late TLR (hazard ratio, 0.63 [0.43–0.93]; P =0.02). The ability of MLA to predict late TLR was further assessed using receiver operating characteristic analysis. MLA was found to be an acceptable discriminator for both PES (c=0.7448) and BMS (c=0.7329). Finally, the optimal thresholds of MLA that best predicted subsequent TLR-free survival were determined to be 4.2 mm 2 for PES and 4.0 mm 2 for BMS.

Conclusion— In the combined IVUS analysis of TAXUS IV, V, and VI, patients who did not require TLR within the first 9 months had a high subsequent TLR-free survival rate whether treated with PES or BMS. MLA measured by IVUS at 9 months predicted subsequent TLR with a cutoff similar to intermediate, de novo lesions in native coronary arteries.

Success, safety, and efficacy of implantation of diamond-like carbon-coated stents

The aim of this study was to evaluate safety and clinically defined efficacy of the implantation of a new stent coated with diamond-like carbon (DLC stent), in a group of patients who underwent percutaneous transluminal coronary revascularization procedures in two hemodynamic centers. This study was an observational prospective nonrandomized study that included 196 patients with a total of 236 significant de novo atheromatous coronary lesions, in which 245 DLC stents were implanted. The primary end point of this study was a composite of major cardiovascular events (death or acute myocardial infarction with or without Q) and need for target lesion revascularization (TLR) or target vessel revascularization (TVR) procedure during the first 48 hours and at 6 months after the DLC stent implantation. All patients had a myocardial perfusion imaging study with Tl(201) at 6 months after DLC stent implantation. Only patients with a myocardial perfusion imaging study indicative of myocardial ischemia were then submitted for a new coronary angiogram. No major cardiovascular event or emergency TVR occurred during hospitalization. At 6-month follow-up no major cardiovascular event occurred either, whereas the rate for TLR was 5.6% and that for TVR was 7.65%. This preliminary study provides enough clinical evidence that implantation of intracoronary bare metal stents coated with diamond-like carbon is associated with high success rates, safety, and efficacy, both in the hospital and at the 6-month follow-up after the interventional procedure.

[Treatment of intrastent restenosis]

In-stent restenosis (ISR) remains an important limitation after stent implantation occurring in 20-30% of patients. Different techniques and treatments have been evaluated in this setting. Repeat balloon angioplasty alone has been rapidly followed by ablative techniques such as laser, rotational atherectomy or implantation of a second stent within the stent. Cutting balloon represents another alternative technique. None of these techniques has proven its superiority over plain balloon angioplasty alone. Brachytherapy is the only effective treatment for ISR by significantly decreasing recurrent restenosis rate at follow-up. However, its use is limited by cost and infrastructure associated with the risk of late thrombosis requiring prolonged antiplatelet therapy. Surgical treatment can be proposed in recurrent ISR as well as medical therapy alone in pauci-symptomatic patients. New drug-eluting stents are under evaluation in this indication.

Analysis of nonintervention strategy for in-stent restenosis in Pauci- or asymptomatic patients

Between January 1996 and May 2000, we retrospectively identified 66 patients (61 +/- 11 years) with in-stent restenosis who did not undergo percutaneous coronary intervention and/or bypass surgery and were maintained on medical treatment alone. In-stent restenosis was diffuse or proliferative in 86% of these patients. At 33 +/- 11 months, 2 patients died, none developed myocardial infarction, and 6 (9%) had target lesion revascularization only (repeat percutaneous transluminal coronary angioplasty). Medical treatment alone was associated with a good long-term clinical follow-up in selected patients with significant documented in-stent restenosis.

Patient care before and after percutaneous coronary artery interventions

Care of the patient before and after percutaneous coronary interventions has changed largely because of the increased use of stents. Important patient management issues include the evaluation of chest pain after the procedure, recognition of acute vessel closure during the periprocedural period, management of the vascular access site, and prevention of contrast-induced renal dysfunction. Risk factor modification and drug therapies are important interventions for the secondary prevention of coronary events. Functional testing has a meaningful role in the evaluation of some patients after coronary intervention. It is important for the specialist in internal medicine to have a firm working knowledge of the various aspects of patient care before and after these procedures because their role in the management of these patients is increasing.

A paclitaxel-eluting stent for the prevention of coronary restenosis

BACKGROUND

Intimal hyperplasia and resulting restenosis limit the efficacy of coronary stenting. We studied a coronary stent coated with the antiproliferative agent paclitaxel as a means of preventing restenosis.

METHODS

We conducted a multicenter, randomized, controlled, triple-blind study to evaluate the ability of a paclitaxel-eluting stent to inhibit restenosis. At three centers, 177 patients with discrete coronary lesions (<15 mm in length, 2.25 to 3.5 mm in diameter) underwent implantation of paclitaxel-eluting stents (low dose, 1.3 microg per square millimeter, or high dose, 3.1 microg per square millimeter) or control stents. Antiplatelet therapies included aspirin with ticlopidine (120 patients), clopidogrel (18 patients), or cilostazol (37 patients). Clinical follow-up was performed at one month and four to six months, and angiographic follow-up at four to six months.

RESULTS

Technical success was achieved in 99 percent of the patients (176 of 177). At follow-up, the high-dose group, as compared with the control group, had significantly better results for the degree of stenosis (mean [+/-SD], 14+/-21 percent vs. 39+/-27 percent; P<0.001), late loss of luminal diameter (0.29+/-0.72 mm vs. 1.04+/-0.83 mm, P<0.001), and restenosis of more than 50 percent (4 percent vs. 27 percent, P<0.001). Intravascular ultrasound analysis demonstrated a dose-dependent reduction in the volume of intimal hyperplasia (31, 18, and 13 mm3, in the high-dose, low-dose, and control groups, respectively). There was a higher rate of major cardiac events in patients receiving cilostazol than in those receiving ticlopidine or clopidogrel. Among patients receiving ticlopidine or clopidogrel, event-free survival was 98 percent and 100 percent in the high-dose and control groups, respectively, at one month, and 96 percent in both at four to six months.

CONCLUSIONS

Paclitaxel-eluting stents used with conventional antiplatelet therapy effectively inhibit restenosis and neointimal hyperplasia, with a safety profile similar to that of standard stents.