Histopathological findings of new in-stent lesions developed beyond five years.

We analyzed 14 cases of new lesions inside implanted bare-metal stents. In every case, there was no angiographic restenosis within 3 years, but a new lesion was observed inside a stented segment at long-term follow-up (>5 years). Fourteen cases were evaluated: 9 with Wiktor stents, 2 with Palmaz-Schatz stents, and 3 with ACS Multilink stents. The interval from stent implantation to follow-up angiography was 63-147 months (89 +/- 23). Thirteen lesions were treated by percutaneous coronary intervention (PCI) and stenotic tissue was obtained by directional coronary atherectomy (DCA) in 10 cases. All retrieved samples were composed of newly developed atherosclerosis facing the healed neointimal layer, and four samples showed histopathological findings of acute coronary syndrome. Stent struts were retrieved in four cases and no inflammation was observed surrounding them. Qualitative and quantitative analysis of stent struts was performed in two cases that showed no metal corrosion. These findings suggest that new atherosclerotic progression occurred inside the implanted stent without peristrut inflammation.

Serial angioscopic findings after successful intracoronary brachytherapy for in-stent restenosis.

The intracoronary changes that occur after brachytherapy for in-stent restenosis (ISR) have yet to be fully established. The purpose of this study in patients who had ISR was to examine the serial angioscopic changes in intracoronary lesions that occurred after brachytherapy. Forty-four patients who had ISR (49 lesions) underwent balloon angioplasty (n = 34) or directional atherectomy (n = 15), followed by intracoronary brachytherapy using a beta-emitting phosphorus-32 source wire. Angioscopic investigations were performed 3 and 9 months after brachytherapy. Uncovered stents were detected in 63.3% of lesions at 3 months. A significant decrease (p = 0.028) in this prevalence occurred over the next 6 months, with 36% of lesions having uncovered stents at 9 months. At 3 months, 33% of the lesions had visible erosion or ulceration and superficial thrombus. The prevalence of these characteristics was decreased at 9 months, although 17% of the lesions were still ulcerated or eroded at that time. Protruding thrombus was not observed in any lesion at 3 and 9 months. In conclusion, uncovered stents and intimal erosions or ulcerations were still present 9 months after brachytherapy in 36% and 17% of lesions, respectively. These results suggest that the healing process was not completed 9 months after brachytherapy in approximately 33% of lesions.

Lesion regression after percutaneous coronary intervention for unprotected left main trunk disease.

BACKGROUND: Although some studies have documented the six-month angiographic outcomes of percutaneous coronary intervention (PCI) with new devices for unprotected left main trunk disease (ULMTD), a long-term angiographic analysis is mandatory to evaluate the safety and effectiveness of this procedure. This study aims to assess a long-term (one year or more) angiographic analysis after PCI for this lesion. METHODS: PCI was performed for 225 ULMTD with de novo or restenotic lesions. There were 19 deaths and 12 repeat PCIs during the hospital stay. The remaining 194 lesions were followed, and 126 lesions showed no angiographic restenosis or target lesion revascularization within six months. Finally, long-term quantitative angiographic follow-up was completed in 78 lesions (mean 2.4 years, maximum 7.5 years after PCI). RESULTS: Minimal lumen diameter increased significantly from 2.46 +/- 0.59 mm to 2.72 +/- 0.65 mm (p < 0.0001) and percent diameter stenosis decreased significantly from 26 +/- 14% to 19 +/- 14% (p < 0.0001) between the six-month and the long-term follow-ups. No additional restenosis or new lesions were found at long-term follow-up, and significant lesion regression was ascertained in each procedure (directional coronary atherectomy, p < 0.005; ballooning, p < 0.005; stenting, p < 0.05). CONCLUSIONS: These findings support the safety and effectiveness of PCI for ULMTD during the long-term period.

New technique for superior guiding catheter support during advancement of a balloon in coronary angioplasty: the anchor technique.

To get superior guiding catheter support, we tried a new method called the anchor technique. By inflating a balloon in a nontarget vessel and holding its shaft with backward force while advancing another balloon, the anchor effect for the guiding catheter could be obtained and it appeared to be helpful for a balloon or a stent to cross the target lesion.

Biodegradable stents as a platform to drug loading.

Despite technical and mechanical improvement in coronary stents the incidence of restenosis caused by in-stent neointimal hyperplasia remains high. Oral administration of numerous pharmacological agents has failed to reduce restenosis after coronary stenting in humans, possibly owing to insufficient local drug concentration. Therefore, drug-eluting stents were developed as a vehicle for local drug administration. The authors developed a new drug-eluting polymer stent that is made of poly-l-lactic acid polymer mixed with tranilast, an anti-allergic drug that inhibits the migration and proliferation of vascular smooth muscle cells induced by platelet-derived growth factor and transforming growth factor->1. Polymer stents might be superior to polymer-coated metallic stents as local drug delivery stents in terms of biodegradation and the amount of loaded drug. Drug-mixed polymer stents can be loaded with a larger amount of drug than can drug-coated metallic stents because the polymer stent struts can contain the drug. Clinical application is required to assess the safety and efficacy of drug-eluting polymer stents against stent restenosis.

Comparison of the self-expanding Radius stent and the balloon-expandable Multilink stent for elective treatment of coronary stenoses: a serial analysis by intravascular ultrasound.

We compared the outcome of the self-expanding Radius stent and the balloon-expandable Multilink stent serially by angiography and intravascular ultrasound. Successful stent deployment was achieved in 66 lesions of 56 stable angina patients (34 lesions with Radius stents and 32 lesions with Multilink stents). At follow-up, there were no significant differences in minimal lumen diameter or percent diameter stenosis between the groups, nor in restenosis rates, although the Radius stent group rate was slightly lower (23.5% vs. 31.3%). In the Radius stent group, stent cross-sectional area (CSA) increased gradually after implantation until the 6-month follow-up (8.37 +/- 1.83 to 10.16 +/- 2.59 mm(2); n = 15), giving a larger CSA (P = 0.03) than the Multilink stent group, which decreased (9.00 +/- 2.05 to 8.27 +/- 2.15 mm(2); n = 17). The lumen CSA was also slightly larger (6.82 +/- 3.06 vs. 5.84 +/- 1.85 mm(2); P = 0.29) in the Radius stent group. These findings indicated that the Radius stent enlarged progressively after implantation, which might be useful for prevention of restenosis.

Biodegradable Polymeric Stents.

To overcome several problems of conventional metallic stents, there have been many attempts to manufacture stents made of biodegradable materials. Although some studies have noted various degrees of inflammatory responses after biodegradable stent implantation, stents made of poly-l-lactic acid (PLLA) showed high biocompatibility with minimal inflammatory response and neointimal formation in porcine coronary arteries. Therefore, PLLA materials are more likely to cover the specific need for human coronary arteries in terms of biodegradation period and scaffolding ability over 6 months. A clinical study of PLLA self-expanding stent implantation is underway in Japan. The initial and 6-month results are favorable and suggest the feasibility, safety, and efficacy of the PLLA biodegradable stent in humans. However, long-term follow-up with larger numbers of patients will be required to validate the long-term efficacy of PLLA stents.