BACKGROUND: Several stents are now available for the treatment of failed or suboptimal angioplasty. However, one of the limitations of stents is difficult to deploy especially in tortuous vessels, lesions at a bend, and distal to previously deployed stents. The AVE Micro-II stent has a very low profile(1.65mm), optimum radio-opacity, and highly flexible properties. It is mounted on a semi-compliant balloon with a monorail delivery system. Therefore, it is easy to operate and feasible in tortuous, distal lesions and variety of lesion lengths. We report clinical outcomes and angiographic follow up results of AVE Micro-II stent. METHODS: Between January 1996 and September 1996, 77 patients were stented with the AVE Micro-II stent. Six-months follow-up angiogram was performed in 57 patients(64 lesions, follow-up rate : 74%). RESULTS: The overall angiographic restenosis rate was 26.6%. By univariable analysis, the rate of restenosis was significantly higher for stents in angulated lesions, in smaller post-stent luminal diameter, in the left anterior descending artery lesion than the right coronary artery, in ostial lesion(p=0.02), in peristent dissecting lesions(p=0.02), in tortuous proximal vessels(p=0.03). Stenting of angulated lesions(p=0.0001, Odds ratio=54.64), small post-stent luminal diameter(p=0.01, Odds ratio=5.46), and the left anterior descending artery than the right coronary artery(p=0.03, Odds ratio=17.2) were the strong independent predictors of restenosis in a multiple logistic regression analysis. Event-free survival(freedom from death, myocardial infarction or revascularization) was 80.7% at 6 months. CONCLUSIONS: 1) The AVE Micro-II stent can be placed safely and efficiently. 2) The angiographic restenosis rate was 26.6%, and 80.7% of patients remained free of cardiovascular events at 6 months. 3) Stenting of angulated lesions, small post-stent luminal diameter, and the left anterior descending artery than the right coronary artery are associated with higher rates of restenosis.
Angioplasty ; Arteries ; Coronary Vessels ; Disease-Free Survival ; Follow-Up Studies* ; Humans ; Logistic Models ; Myocardial Infarction ; Phenobarbital ; Stents*

BACKGROUND: Despite of the first coronary wallstent implantation ushered in the new era in interventional cardiology with the purpose of circumventing the two major limitation of coronary balloon angioplasty, early acute occlusion and late restenosis, however, previous investigators suggested the high rate of subacute occlusion after original wallstent implantation. Recently the low incidence of the subacute closure and restenosis rate with the newely modified less shortening coronary wallstent in native coronary artery and in aortocoronary vein grafts were reported. In this study we report the acute and 6 months follow up results with less shortening coronary wall stent in 32 patients. METHODS: Thirty two patients were enrolled from March 1996 through February 1997 at the Yonsei cardiovascular center of Yonsei University. The specific angiographic criteria for enrollment included at least 70% stenosis and a lesion that was 20mm or more in length and a vessel diameter of at least 2.5mm. Enteric coated aspirin(100mg daily) and ticlopidine(500mg daily) at least 3 days before the procedure and received continuous infusion of 24,000U of heparin for 1day after the procedure. Angiography was performed in two orthogonal views at pre, post procedure and 6months later. Quantitative analysis was performed with the use of the electronic caliper comparing to the empty catheter. All continuous variables were expressed as mean SD and analyzed with the t-test. Differences between groups were analyzed with Chi-square analysis and Fishers Exact test where appropriate. RESULTS: The newly modified Coronary Less Shortening Wallstents were successfully implanted in all the 35 diffuse coronary lesions(more than 20mm in length) of the 32 patients, including 15 pts of acute myocardial infarction, 14 pts of unstable angina, and 3 pts of stable angina. Average 6 months follow up angiography was performed in 26 patients. Immediate angiographic results with Less Shortening Wallstent comparing with 6 months follow up were 3.0+/-0.4mm and 1.7+/-0.9mm in minimal luminal diameter(MLD), 5.1+/-9.1% and 46.8+/-25.8% in diameter stenosis(DS). During the in-hospital phase, no major cardiac event occurred except 2 cases of transmural myocardial infarction, including one of stent thrombosis(3.1%) and one of side branch occlusion, despite of inclusion of 7 cases of threatened occlusion in the long lesion. The restenosis rate at follow up angiography was 30.7%(8/26 pts). The restenosis rate was higher in patients with stent insertion into right coronary artery or adjuvant high pressure oversize ballooning after stent insertion but not statistically significant. CONCLUSIONS: The results of this study suggested that new Less Shortening Wallstent might reduce the requirement of multiple stent in the long lesion and a lower rate of subacute thrombotic occlusion in comparison to the reports with its prototype. Restenosis rate was not significantly different from other types of stents. Althouth the restenosis rate was high in patients with stent insertion, there was no statistical significance probably due to small sample size. But further large scale long term follow-up study is needed to evaluate the role of new Less Shortening Wallstent.
Angina, Stable ; Angina, Unstable ; Angiography ; Angioplasty, Balloon, Coronary ; Cardiology ; Catheters ; Constriction, Pathologic ; Coronary Artery Disease* ; Coronary Vessels* ; Follow-Up Studies* ; Heparin ; Humans ; Incidence ; Myocardial Infarction ; Phenobarbital ; Research Personnel ; Sample Size ; Stents ; Transplants ; Veins

BACKGROUND: Coronary stenting is known to reduce the rates of restenosis in focal lesions, but the efficacy of stents for long lesions have not been thoroughly defined. To evaluate the immediate and follow-up results of three different types of stents in lesions longer than 20mm, consecutive series of patients (pts) were reviewed. METHODS: Between February 1996 and January 1997, 123 patients (male 68.3%, mean age 57+/-10 years) with a total of 130 lesions underwent long stent : stenting. Excluding multiple stents and unplanned use for acute closure fifty-three pts (56 lesions) were treated with the Microstent II (M-II):30 pts (31 lesions) received the Less Shortening Wallstent (WA):and 40 pts (43 lesions) were treated by the Gianturco-Roubin II stent (GR-II). RESULTS: With the clinical success defined as <30% residual stenosis without death, CABG, Q-wave MI was achieved in 93% with the M-II, 94% with the WA and 95% with the GR-II. Stent thrombosis occurred 0% in M-II, 1.5% in WA and 2.3% in GR-II. Clinical success and stent thrombosis rates were not different between the three types of stents. Follow-up (FU) quantitative angiography was obtained from 34 pts (64%) in M-II, 25 lesions (83%) in WA and 26 pts (65%) in GR-II after 6 months. Restenosis rate defined as <0A65B>50% diameter stenosis at FU was 26% in M-II, 32% in WA and 38% in GR-II:there was no significant difference between the three stents. Target lesion revascularization (TLR) defined as CABG or target lesion PTCA at FU was 17.6% in M-II, 12% in WA and 23.1% in GR-II. Restenosis rate correlated closely with lesion length (p-value-0.03, Odds ratio-1.096) and small post-stent luminal diameter (p-value-0.002, Odds ratio-0.063) in a mu-ltivariable analysis. CONCLUSION: Coronary stenting for long lesions can be safely performed with acceptable complication rates using any of the three types of stents. Restenosis and late outcome was not related to type of stent.
Angiography ; Constriction, Pathologic ; Follow-Up Studies ; Humans ; Phenobarbital ; Stents* ; Thrombosis