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Percutaneous coronary interventions (PCI) performed on large-scale basis in routine practice with documented long-term clinical benefit for the patient are balloon angioplasty introduced in 1977 and coronary stenting since 1986. Other coronary devices, so-called 'adjunctive', have triggered a great admiration at the time of its initial clinical application but showed to be less successful at the long-term follow-up. However, many adjunctive devices are still necessary in 1-2% of all PCI procedures for complex cases. This article is a short, comprehensive review retracing the conception and destiny of these devices. Coronary balloon catheters, a standard device with advance 'therapeutic' features comprise: cutting, drug eluting and high pressure non-compliant balloon catheters. Atherectomy devices can be directional for lesions 'debulking', rotational (Rotablator) for calcified, long lesions and recently Orbitral supposed to have less no-reflow phenomenon. Excimer Laser angioplasty for treatment of 'uncrossable' lesion was claimed much in the past. Brachytherapy is used almost exclusively for in-stent restenosis. A numerous thrombectomy and embolic protection devices exist but none has shown a proven clinical benefit in randomized studies. With an advancement in medical technology adjunctive devices will play more important role in the future, especially for recanalization of chronic total occlusion and during acute myocardial infarction.

We sought to determine the incidence of coronary perforations, predisposing factors, and in-hospital and late outcome of patients with coronary perforations. Perforations occurred in 0.84% of treated lesions and more frequently in patients with complex lesions after atheroablative procedures and who underwent intravascular ultrasound guided lumen optimization. The incidence of adverse events, emergency coronary artery bypass grafting and death significantly decreased over time.

Background — The safety and efficacy of percutaneous coronary intervention of de novo lesions in unprotected left main coronary arteries remains an unresolved issue. Methods and Results — We analyzed 67 consecutive patients treated with the following devices: 39 with stents, 12 with rotational atherectomy plus stents, 13 with directional coronary atherectomy plus stents (a total of 64 patients were treated with stents), and 3 patients with directional coronary atherectomy only. The reference vessel size was 3.78±0.73 mm and lesion length was 6.6±3.0 mm. In-hospital complications were 2 coronary artery bypass grafts (CABGs) (3.0%), 2 Q-wave myocardial infarctions (MIs) (3.0%), and 3 non-Q-wave MIs (4.5%); there were no deaths. The estimated cardiac survival at 3 years was 91%. The cardiac mortality rate was higher in patients with Parsonnet score >15 versus ≤15 (21.4% versus 4.2%, P =0.02) at 3 years. The independent covariate of cardiac death was preserved left ventricular ejection fraction; for combined cardiac events (cardiac death, MI, repeat revascularization) it was large reference vessel size. Follow-up angiography at 5±2 months in 85% of eligible patients revealed 31.4% restenosis. Extending the follow-up to 31±23 months (19 patients with follow-up beyond 3 years) the cumulative event rates were 11 deaths (16.4%), 8 of them cardiac (11.9%), 2 (3.0%) MI, and 16 (23.9%) repeat revascularizations (CABG in 5 patients). Conclusions — Elective percutaneous coronary intervention of de novo lesions in left main coronary arteries is feasible, with low procedural risk. The long-term follow-up revealed a high rate of angiographic restenosis and repeat revascularization, with a relatively high incidence of cardiac death. Reference vessel size and left ventricular function are the most important predictors of favorable follow-up.

OBJECTIVESThe purpose of this study was to evaluate the approach of intravascular ultrasound (IVUS)-guided percutaneous transluminal coronary angioplasty (PTCA) with spot stenting (SS) for the treatment of long coronary lesions.BACKGROUNDTreating long coronary lesions with balloon angioplasty results in suboptimal short- and long-term outcomes. Full lesion coverage with traditional stenting (TS) has been associated with a high restenosis rate.METHODSWe prospectively evaluated a consecutive series of 130 long lesions (>15 mm) in 101 patients treated with IVUS-guided PTCA and SS. The results were compared with those of TS in a matched group of patients. Coronary angioplasty was performed with a balloon to vessel ratio of 1:1, according to the IVUS media-to-media diameter of the vessel at the lesion site, to achieve prespecified IVUS criteria: lumen cross-sectional area (CSA) ≥5.5 mm2or ≥50% of the vessel CSA at the lesion site. The stents were implanted only in the vessel segment where the criteria were not met.RESULTSIn the SS group, stents were implanted in 67 of 130 lesions, and the mean stent length was shorter than that of lesions in the matched TS group (10.4 ± 13 mm vs. 32.4 ± 13 mm, p < 0.005). The 30-day major adverse cardiac event (MACE) rate was similar (5%) for both groups. Angiographic restenosis was 25% with IVUS-guided SS, as compared with 39% in the TS group (p < 0.05). Follow-up MACE and target lesion revascularization rates were lower in the SS group than in the TS group (22% vs. 38% [p < 0.05] and 19% vs. 34% [p < 0.05], respectively).CONCLUSIONSIntravascular ultrasound-guided SS for the treatment of long coronary lesions is associated with good acute outcome. Angiographic restenosis and follow-up MACE rates were significantly lower than those with TS.

OBJECTIVESWe sought to evaluate the relation between stented segment length and restenosis.BACKGROUNDMultiple or long coronary stents are now being implanted in long lesions or in tandem lesions. A longer stented segment might result in a higher probability of restenosis. However, there is little information available on the relation between stented segment length and restenosis.METHODSBetween April 1995 and December 1996, 725 patients with 1,090 lesions underwent stenting. Lesions were divided into three groups according to the length of the stented segment: 1) group I (n = 565): stented segment length ≤20 mm; 2) group II (n = 278): stented segment length >20 but ≤35 mm; and 3) group III (n = 247): stented segment length >35 mm.RESULTSThere was no significant difference in the incidence of subacute stent thrombosis among the three groups (0.4% in group I, 0.4% in group II, 1.2% in group III; p = NS). The minimal lumen diameter (MLD) after stenting was greater in group I than in group III (3.04 ± 0.60 mm in group I, 3.01 ± 0.54 mm in group II, 2.91 ± 0.58 mm in group III; p < 0.05). At follow up, a smaller MLD was observed in group III as compared with group I and group II (2.04 ± 0.93 mm in group I, 1.92 ± 1.00 mm in group II, 1.47 ± 0.97 mm in group III; p < 0.01). The restenosis rates were 23.9% in group I, 34.6% in group II and 47.2% in group III (p < 0.01). Using multivariate analysis, the longer stented segment, the angiographic reference vessel diameter and the percent diameter stenosis after stenting were independent predictors of restenosis.CONCLUSIONSThe present study shows that a longer stented segment is an independent predictor of restenosis without an influence on the risk of subacute thrombosis.

To determine if vessel wall overstretching during coronary stenting is associated with a higher restenosis rate, the intravascular ultrasound morphological evaluation was performed following ultrasound criteria. A total of 468 lesions with successful coronary Palmaz-Schatz stenting guided by intravascular ultrasound were classified into the no overstretching group (n = 295) and the overstretching group (n = 147). There were 26 lesions not classifiable due to the poststent morphology. Balloon-to-vessel ratio was 1.12 ± 0.17 in the no focal overstretching group and 1.20 ± 0.20 in the overstretching group (P < 0.0002). Follow-up angiogram was performed in 77% of no focal overstretching group and in 75% of the focal overstretching group. The restenosis rate of the no focal overstretching group was 19.8% and 20.9% in the focal overstretching group, respectively (P = 0.65). Focal overstretching was more frequent following balloon oversizing. No increase in restenosis rate, found in focal overstretched stented lesions, leads us to the hypothesis of a regulation of smooth-muscle-cell proliferation activated by the normalization of blood flow and of shear stress, when stent implantation succeeds in optimally improving the lumen. Cathet. Cardiovasc. Intervent. 48:24–30, 1999. © 1999 Wiley-Liss, Inc.

The present study evaluated the acute and follow-up results of stenting following aggressive rotational atherectomy compared with stenting following less aggressive rotational atherectomy. Recent work has demonstrated that stenting following rotational atherectomy is a promising strategy for complex and calcified lesions. However, there is little information available regarding the optimal procedural technique of rotational atherectomy to be employed before stent implantation. Between May 1995 and February 1997, 162 lesions in 126 patients were stented following rotational atherectomy because of the presence of severe calcification on fluoroscopy or intravascular ultrasound (95%). The lesions were divided as to whether aggressive rotational atherectomy was performed or not. Aggressive rotational atherectomy, defined as the use of a final burr size > or =2.25 mm and/or final burr/vessel ratio > or =0.8, was performed in 56 lesions. A less aggressive rotational atherectomy strategy was performed in 106 lesions. Procedural Q-wave (8.9% vs. 1.9%, P

The present study evaluated acute and late results with stenting following directional coronary atherectomy (DCA) for the lesions in the left anterior descending coronary artery (LAD). Between April 1995 and January 1997, 200 LAD lesions withor =3 mm reference vessel diameter were treated with coronary stents. The lesions were divided as to whether or not DCA was performed before stenting; 1) stenting alone (n = 163) and 2) debulking and stenting (n = 37). There were no significant differences in the incidences of complications except for non-Q-wave myocardial infarction that was more frequent in patients with debulking and stenting than in those with stenting alone (13.5% vs. 2.4%, P0.05). A greater acute lumen gain (2.85 +/- 0.66 vs. 2.25+/-0.60 mm, P0.01) and minimal lumen diameter (3.64+/-0.56 vs. 3.15+/-0.41 mm, P0.01) after stenting were observed in patients with debulking and stenting than in those with stenting alone. At follow-up patients with debulking and stenting continued to have a greater minimal lumen diameter (2.88+/-0.72 vs. 2.15+/-0.85 mm, P0.01) and had a lower restenosis rate (6.3% vs. 23.1%, P0.05) than those with stenting alone. Stenting following DCA appears to be advantageous in the LAD lesions withor =3 mm reference vessel diameter.

Objectives. This study sought to compare the short- and long-term outcomes of elderly patients undergoing coronary artery stenting with those of younger patients and to determine the long-term clinical outcome and survival of elderly patients post stent implantation.Background. Elderly patients undergoing coronary revascularization are considered a high-risk group. Few data exist that relate the results of stenting in treating coronary artery disease in the elderly population.Methods. All elderly patients ≥75 years of age who underwent coronary artery stenting between March 1993 and July 1997 (n = 137) at our center were compared to the patients

We report a patient with systemic sclerosis having implantation of a 35 mm beStent with immediate success but developing angina at follow-up. A focal stent collapse with focal hyperplasia in and outside the stent was documented by ultrasound after 2 mos. A 14mm Palmaz-Schatz stent was successfully deployed into the collapsed beStent, with good 6-mo angiographic result. The stent collapse was probably due to unequal distribution of radial forces and possibly reactive hyperplasia in this unique patient with systemic sclerosis.

The mechanical approach in the recanalization of total coronary occlusions consisted of the use of a new 0.014-inch standard coronary guide wire with jointless spring coil design that improves steering characteristics and tip stiffness. In addition, a 0.014-inch soft tip wire with hydrophilic coating and low-profile 1.5 mm over-the-wire balloons were used. The first wire was used selectively in 86 patients to treat 95 total occlusions, of which 51 (54%) were older than 3 months. Unfavorable angiographic characteristics were present in 79 (83%) of 95 lesions. Overall crossing success was 71% (67 of 95 lesions). Complications were one coronary perforation with cardiac tamponade necessitating emergency bypass surgery. In conclusion, the mechanical approach with the use of the standard coronary guide wire with jointless spring coil design provides a high success rate in the recanalization of unfavorable total occlusions.

Objective To analyze the results of implantation of six different intracoronary stents without the use of prolonged anticoagulation. Material and Methods Between Mar. 30, 1993, and Jun. 30,1995,889 patients with 1,194 coronary or vein graft lesions underwent implantation of one of six types of stents—Palmaz-Schatz, Gianturco-Roubin, Wiktor, Micro, Cordis, or Wallstent. The patients were classified into seven groups on the basis of the type of stent that was implanted, including one group with combined use of two or more types of stents. Among the 851 patients with successful stent delivery and without major complications, 801 received only antiplatelet therapy, and 50 received a standard anticoagulation regimen. One-month clinical follow-up data were obtained in all patients, and clinical events were investigated. Results The mean number of stents was 1.8 per lesion and 2.4 per patient. Procedural success was achieved in 93% of the lesions. The clinical success rate at 1 month was 90%. Intravascular ultrasound assessment was performed in 90% of the lesions. The final minimal luminal cross-sectional area of the stent increased from 6.8 to 7.8 mm 2 after intravascular ultrasound-guided optimization. Within 1 month, 16 stent thrombosis events (1.9%) occurred. No significant differences were noted in stent thrombosis rates among the various stent cohorts. Multivariate logistic regression analysis revealed that the final stent minimal luminal diameter measured by intravascular ultrasonography was the only variable associated with stent thrombosis. Conclusion This study showed that six different stents could possibly be inserted without subsequent anticoagulation if optimal stent expansion and total lesion coverage were achieved.

The Wallstent (Schneider, Bulach, Switzerland) is available in different lengths without much compromise in flexibility and radial support compared to some other stents. We treated 24 patients (26 vessels) with diffuse coronary lesions or vein graft lesions with intravascular ultrasound-guided peripheral Wallstent implantation. Average balloon pressure during stent optimization was 16.4 ± 2.7 atm. The stents could be successfully implanted in 24 vessels. Minimal lumen diameter and percent diameter stenosis after stenting were 3.60 ± 0.62 mm and −8 ± 13%, respectively. Average stent length was 63.7 ± 22.7 mm. There was one procedure-related complication. After stenting, all patients were treated only with antiplatelet agents. During 1-month follow-up, there was one subacute stent thrombosis due to incomplete coverage of a distal dissection. These preliminary results show the feasibility of this novel approach in selected lesions. © 1996 Wiley-Liss, Inc.

It is generally believed that the Palmaz-Schatz stent maintains a strong radial force, preventing stent recoil. However, the capacity to prevent recoil is largely governed by the hardness or resistance of the lesion. We report two cases of “acute Palmaz-Schatz stent recoil,” documented by intravascular ultrasound, and suggest a novel treatment of this unusual problem. © 1996 Wiley-Liss, Inc.

Objectives. The purpose of this study was to determine the immedite and long-term angiographic and clinical results of coronary stenting as a specific therapy for intracoronary dissection associated with acute or threatened closure complicating percutaneous transluminal coronary angioplasty. Background. Published reports contain conflicting results with regard to the benefit of stent insertion for coronary dissection. In particular, there is a wide range in the reported rates of subacute occlusion. Methods. Palmaz-Schatz stents were inserted in 56 patients who had significant dissections and acute or threatened closure complcating angioplasty. An attempt was made to cover the entire site of the dissection with short or standard or multiple Palmaz-Schatz stents. The use of the short stent allowed complete coverage of the dissection, specifically in situations such as marked vessel tortuosity or the need to place a stent distal to a deployed stent. Results. A single steel was implanted in 24 patients and multiple stents were implanted in 32 patients. A total of 138 stents (78 standard 60 short stents) were implanted, The primary clinical success rate was 88% (49 of 56 patients). Complications occured in seven patients (12.5%): Three patients (5%) required urgent bypass surgery; two patients (4%) had a myocardial infarction; and two patients (4%) died. Subacute occlusion occurred in one patient (2%). Clinical follow-up was available in all patients at a mean of 10 ± 4 months. Thirty-nine (80%) of 49 patients were clinically asymptomatic. Angiographic restenosis was found in 15 (36%) of 42 patients on angiographic follow-up performed a mean of 5 months (median 6) after the procedure in 86% of the eligible patients. Nine patients had successfull repeat angioplasty, and two had elective bypass surgery. Conclusions. The strategy of coronary stenting to completely cover the lesion is an effective treatement for large coronary dissection complicating angioplasty. A total major complication rate of 12.5% may be acceptable for this high risk group.

High speed coronary rotational ablation followed by adjunctive low pressure coronary balloon angioplasty was used in 166 patients. Complex lesions were present in 63% of patients. Clinical success was achieved in 157 patients (95%). Angiographic success rate was 10% in A lesions, 95% in B1 lesions, 98% in B2 lesions, and 93% in C lesions. Mean vessel lumen diameter has increased from 0.4 mm to 1.4 mm after rotational ablation and to 2.3 mm following adjunctive balloon angioplasty. Left ventricular dysfunction, the presence of total occlusion, and the severity of stenosis before theprocedure were predictive of clinical failure. There were three abrupt vessel closures (1.8%) with one Q wave myocardial infarction. Non-Q wave myocardial infarction occurred in 14 patients (8.4%) and three patients died during hospitalisation (1.8%). We conclude that rotational atherectomy followed by adjunctive low pressure balloon angioplasty gives comparable high success rates in different coronary lesions. © 1993 Wiiey-Liss, Inc.

We studied 32 patients (age 58 +/- 9 years) who had been treated with a Palmaz-Schatz stent after significant dissection complicating percutaneous transluminal coronary angioplasty (PTCA). We attempted to cover the entire site of dissection with prosthesis. The presence of dissection after PTCA was associated with Thrombolysis in Myocardial Infarction grade 0 to 1 flow in 19 patients and grade 2 flow in 13. The stented arteries were: left anterior descending artery in 19 patients, right coronary artery in seven, and left circumflex artery in five. A single stent was implanted in 11 and multiple stents in 21 patients. Angiographic success was achieved in 30 patients (94%). Two patients (6%) had urgent coronary artery bypass graft surgery, two (6%) had a myocardial infarction, and one (3%) patient died. Subacute occlusion occurred in one patient (3%). Angiographic restenosis was found in three of nine patients (33%) with a single stent and 11 of 17 (65%) with multiple stents. Clinical follow-up at 11 +/- 3 months showed the necessity of coronary artery bypass graft surgery in two patients and repeat PTCA in nine (31%). We conclude that coronary stenting is an effective treatment for significant coronary dissection after PTCA with an acceptable incidence of major cardiac events at follow-up.

In a retrospective study of 365 chronic total occlusions that were submitted for angioplasty, we studied the influence of 27 clinical, morphologic, and procedural variables as possible predictors of successful outcomes. Success rate was shown to be significantly influenced by the following variables: operator experience (41% in early patients, first 6 months; 73% in late patients, last 6 months of entire series; p less than 0.001), duration of occlusion (less than or equal to 1 month, 89%; 1 to 3 months 87%; greater than or equal to 3 months 45%; unknown 60%; p less than 0.001), morphology of occlusion (tapered, 83%; abrupt, 51%), length of occlusion (less than or equal to 15 mm, 71%; greater than 15 mm, 60%; p less than 0.001), and bridging collaterals (present, 29%; absent, 67%; p less than 0.001). None of the other clinical, angiographic, or procedural variables correlated with the success rate of coronary angioplasty. The calculated probability for an experienced operator (greater than 100 occlusions attempted) to successfully open an occlusion with favorable morphology (less than or equal to 1 month old, short, tapered, without bridging collaterals) is 99%. An attempt by the same operator to open an occlusion with unfavorable structure (greater than or equal to 3 months old, long, untapered) has only 47% probability of success. The probability increases to 84% when the occlusion is tapered. We concluded that in addition to the duration and the length of occlusion, tapered morphology, bridging collaterals, and operator experience can predict successful angioplasty in chronic total coronary occlusion.

We analyzed all coronary angioplasty procedures performed in patients aged > 70 yr since 1987. There were a total of 92 patients with a mean age of 74 ± 4 yr (range 70–82). The clinical diagnosis was unstable angina in 79%. Single-vessel disease was present in 41%, double-vessel in 29% and triple-vessel in 30% of patients. A left ventricular ejection fraction of Angiographic success was achieved in 96% of stenoses and in 53% of chronic total occlusions attempted. Complete revascularization was achieved in 56% of patients. Complications included three patients (3.2%) who underwent emergency coronary artery bypass grafting, 1 patient (1.1%) who sustained a myocardial infarction and 5 patients (5.4%) who died. During hospitalization, which averaged 3 ± 2 days, 1 patient sustained reversible renal failure and 5 patients required blood transfusion for a large groin hematoma. Clinical success at discharge was 83%. At a mean follow-up of 13 months (range 3–45 months), symptomatic improvement was observed in 59 of the 76 patients who had achieved clinical success, with 42 of these patients (55%) being asymptomatic. The following clinical events occurred: myocardial infarction in 1 patient, new percutaneous transluminal coronary angioplasty in 9 and 3 patients died of cardiac reasons. In conclusion, although the immediate mortality rate seems to be higher and asymptomatic status at follow-up lower than in the reported series of angioplasty in non-elderly patients, coronary angioplasty in the elderly is an effective modality of treatment of angina.

We developed an alternative method to stent suitable lesions located in anatomical settings considered to be too complex for regular Palmaz-Schatz stent placement. This method consists of using a disarticulated (one-half) Palmaz-Schatz stent. Eight patients underwent stenting utilizing this method. The left anterior descending was stented in five patients, the right coronary artery in one patient, the proximal and mid shaft of a vein graft in one patient, and a protected left main coronary artery in one patient. In all patients the stents were placed in addition to full stents. In four patients, 1 1/2 stents were placed; two patients had 2 1/2 stents; one patient had 3 1/2 stents and the last patient had a total of 5 stents placed (1 full stent and 8 half stents). One patient had 8 disarticulated stents placed. All half stents prepared for delivery were successfully deployed to the pre-designated angiographic site without complication.

Coronary collaterals demonstrated angiographically are expected to be usable both ways and to remain on standby even if they are no longer used after flow improvement through the physiological pathway. Evidence of these hypotheses is provided by two case reports, one showing spontaneous reversal of collaterals and one showing recruitable reversed collaterals.

In preparation for coronary bypass surgery, digital subtraction angiography (DSA) was used to assess the caliber of the left and right internal mammary arteries and to exclude stenoses of their feeding arteries. In 100 patients (86 males, mean age 56 ± 9 years) DSA was performed with a Siemens Digitron 2 device. A frontal projection was used in 18 patients, and a 10–20 degree right anterior oblique projection was used in 82 patients. The flow was 10 to 25 ml/sec; 20 ml was injected in 45 patients, 30 ml in 41, 40 ml in 5, 50ml in 8, and 60 ml in 1 patient, Judged on the proximal third, visualization of the left and the right internal mammary artery was good in 80 and 72, fair in 17 and 20, and bad in 3 and 8 arteries, respectively. The diameter (mm) was 2.7 ± 0.4 (range 1.8–3.4) and 2.7 ± 0.3 (range 2.0–3.5), and visible length (cm) was 8 ± 5 (range 1–24) and 9 ± 4 (range 2–22) for the two arteries, respectively. The 10–20 degree right anterior oblique view separated the left internal mammary artery better from the descending aorta than the frontal view. In more pronounced right anterior oblique views the ascending aorta interfered with the right internal mammary artery. The quality was not different with 20 ml or 30 ml injections. The feeding arteries could not be assessed in 4 patients. One left subclavian artery was found occluded at the orifice. Incidentally, 2 distal right subclavian stenoses and 2 carotid stenoses were detected. In conclusion, DSA with 20 ml (10 ml/sec) of contrast medium, injected into the ascending aorta in a 15 degree right anterior oblique view, sufficiently visualizes the internal mammary arteries and their feeding vessels before bypass surgery in most patients. Any catheter inserted for coronary or left ventricular angiography can be used.

Randomized trials have shown that implantation of sirolimus-eluting stents (SESs) and paclitaxel-eluting stents (PESs) reduce the incidence of major adverse cardiac events (MACEs) compared with bare metal stents. We compared the impact of SESs and PESs on clinical outcome in medically treated diabetic patients with multivessel stents. In this study, the in-hospital and 9-month clinical outcomes of 260 consecutive diabetic patients who underwent implantation of SESs (147 patients) or PESs (113 patients) were compared. MACEs were defined as death, nonfatal myocardial infarction, and clinically driven target vessel revascularization. The baseline demographic and angiographic characteristics were well matched. An average of 3.0 +/- 1.3 versus 2.8 +/- 1.2 lesions were treated in the SES and PES groups, respectively (p = 0.34), with a mean stented length per patient of 73 +/- 43 versus 61 +/- 36 mm (p = 0.08). No significant difference was observed between the SES and PES groups for in-hospital (6.1% vs 3.5%, p = 0.34) or 9-month MACE (24.5% vs 19.5%, p = 0.34) rates or for subacute (1.4% vs 0.9%, p = 0.72) or late (0.7% vs 0.9%, p = 0.85) stent thrombosis. Insulin-requiring diabetic patients treated with SESs and PESs also had similar demographic and angiographic characteristics and rates of in-hospital (4.7% vs 7.7%, p = 0.57) and 9-month (28.0% vs 38.4%, p = 0.44) MACEs. Insulin-dependent diabetes was the only independent predictor of MACEs (odds ratio 2.68, 95% confidence interval 1.46 to 4.89, p = 0.001). In conclusion, our results demonstrated a relatively high incidence of MACEs in a diabetic population with multivessel disease, despite treatment with drug-eluting stents. In addition, we could not find any clear advantage of 1 type of stent versus the other.

The novel device Frontrunner coronary catheter (FCC), dedicated to recanalization of chronic total occlusions (CTOs), relies on blunt microdissections inside the plaque, allowing passage of guidewire through the lesion and adjunctive angioplasty. In order to evaluate efficacy and safety of recanalization using the FCC device, we included patients with de novo or restenotic CTOs in a native coronary artery with prior failure using a guidewire or considered unsuitable for guidewire attempt in which the FCC was attempted first. Between October 2000 and June 2003, 50 patients with 50 CTOs were included in the study. Thirty-two patients had prior failure with a mechanical wire. Device and angiographic success were obtained in 25 (50%) occlusions: 53% in lesions with prior guidewire failure and 44% when FCCs were attempted first (P = 0.8). During the first year of experience, angiographic success was 42% (5 occlusions) and in the third year 75% (12 occlusions; P = 0.12). Coronary perforation occurred in nine (18.0%) patients, leading to tamponade in two (4%) patients. Perforations occurred in 5 out of 12 attempted patients during the first year and in 4 out of 38 patients in the following period (41.7% vs. 10.5%; P = 0.04). Serious adverse events occurred in five (10%) patients within 30-day follow-up. Four non-Q-wave myocardial infarctions occurred in hospital (clinical success 42%) and one death 7 days after the index procedure. The use of FCC increases the success to open chronic total occlusions refractory to mechanical guidewires or that were considered unsuitable for an attempt with a guidewire. The risk of coronary perforation due to FCC use is relatively high and it can decrease with experience.

We report the first clinical experience in eight patients with a new stent and delivery system specifically designed for the treatment of bifurcational lesions. The device (AST SLK-View system) consists of a premounted stent and a delivery system. The stent has a side aperture, which orients toward the ostium of the side branch. The system allows deployment of the stent while the access to both main and side branches is maintained by two wires. We evaluated this system in nine bifurcations. The location of bifurcations was left descending artery/diagonal branch in four lesions, left circumflex/obtuse marginal branch in three lesions, and postero-lateral branch/posterior descending artery in two lesions. Predilation was performed in six lesions of the main branches and in five lesions of the side branches. The stent was effectively delivered to all bifurcations except for one, in which the target lesion was located at a distal segment and the device could not be delivered. Following stent implantation in the main branch, two lesions at the side branches were treated by stent, while the other lesions were treated by balloon angioplasty without difficulty. Final kissing balloon was performed in four bifurcation lesions. No adverse event was observed during 1 month of clinical follow-up. Treatment of bifurcation lesions with this new dedicated device appears to be feasible. This new device may introduce a new approach for the treatment of coronary bifurcation lesions.

Background: Carotid artery stenting is now used as an alternative to surgical endarterectomy. The availability of cerebral protection systems has expanded the area of application of this procedure. Objective: To assess the feasibility, safety, and immediate and late clinical outcome in patients undergoing percutaneous carotid interventions. Methods: Between January 1999 and December 2000, 100 consecutive patients with 102 carotid artery stenoses were treated (71 men, 29 women, mean (SD) age 67 (8) years): 49 had coronary artery disease, 28 had previous stroke or transient ischaemic attack (TIA). On the basis of the Mayo Clinic carotid endarterectomy risk scale, 73 patients were grade III–IV and 13 grade VI. Results: Baseline diameter stenosis was 78.8 (10)%, with a mean lesion length of 12.6 (5.8) mm. Angiographic success was obtained in 99 lesions (97.0%) with a final diameter stenosis of 2.4 (3.5)%. Procedural success was obtained in 96 patients (96%). Selective cannulation of three carotid arteries was impossible owing to severe vessel tortuosity. Carotid stenting was performed in 97 of the treated lesions, and protection devices were used in 67 lesions. In-hospital complications occurred in seven patients (six TIA, one (category 1) minor stroke). No major stroke or death occurred. All patients were discharged from the hospital after an average of 2.5 days. At 12 (6.2) months of follow up restenosis occurred in three patients (3.4%) (one patient with carotid occlusion had TIA). Six patients had died: two from cerebrovascular events (5 and 11 months after the procedure) and four from cardiovascular causes. Conclusions: Carotid stenting appears feasible and safe, with few major complications. Long term follow up is affected by a high incidence of cardiovascular mortality.

The purpose of this study was to assess the outcome of nonobstructive (or non-flow-limiting) residual dissection (RD) after percutaneous coronary intervention. Results of 124 consecutive native coronary lesions with angiographic nonobstructive RD in 97 patients (RD group) were compared with outcomes of 124 lesions without RD in 100 patients (non-RD group), whose characteristics were matched with those of the RD group. RD occurred after stent implantation (81 of 124 lesions, 65%) or balloon angioplasty (43 of 124 lesions, 35%). Angiographic types of RD were type A in 8 lesions (6%), B in 101 (82%), and C in 15 (12%). Stents were implanted in 65% of the lesions in each group. Clinical success (94% in RD group vs 95% in non-RD group, p = 0.77) and the in-hospital major adverse cardiac event rates were found to be similar in the 2 groups (6% vs 3%, respectively; p = 0.33). The late angiographic and clinical outcomes were also comparable. By intravascular ultrasound (IVUS) evaluation of the dissections in the RD group, area stenosis correlated with the incidence of in-hospital major adverse cardiac events (p = 0.023), whereas the final minimal lumen area correlated inversely with the occurrence of restenosis (p = 0.011). An area stenosis > or =58% was the best predictor for the incidence of in-hospital major adverse cardiac events (sensitivity 0.68, specificity 0.68). Most nonobstructive RDs are "favorable" and do not need stent implantation. IVUS evaluation identifies "unfavorable" nonobstructive (or non-flow-limiting) dissections that might be prone to acute occlusion. Nonobstructive dissections can be left untreated when final IVUS reveals an area stenosis of < 60% at the site of a dissection.

OBJECTIVESThe purpose of this study was to evaluate two different techniques of stent placement in bifurcation lesions.BACKGROUNDAlthough stent placement with dedicated techniques has been suggested to be a useful therapeutic modality for bifurcation lesions, limited information is available if stent placement on the side branch and on the parent branch provides any advantage over a simpler strategy of stenting the parent vessel and balloon angioplasty of the side branch.METHODSBetween March 1993 and April 1999, we treated a total of 92 patients with bifurcation lesions with two strategies: stenting both vessels (group B, n = 53) or stenting the parent vessel and balloon angioplasty of the side branch (group P, n = 39). Paired angiograms were analyzed by quantitative angiography, and clinical follow-up was obtained.RESULTSStent placement on both branches resulted in a lower residual stenosis (7.4 ± 10.9% vs. 23.4% ± 18.7%, p < 0.001) in the side branch. Acute procedural success was similar in the two groups (group B: 87% vs. Group P: 92%). In-hospital major adverse cardiac events (MACE) occurred only in group B (13% vs. 0%, p < 0.05). At the six-month follow-up, the angiographic restenosis rate (group B: 62% vs. Group P: 48%) and the target lesion revascularization rate (38% vs. 36%, respectively) were similar in the two groups. There was no difference in the incidence of six-month total MACE (51% vs. 38%).CONCLUSIONSFor the treatment of true bifurcation lesions, a complex strategy of stenting both vessels provided no advantage in terms of procedural success and late outcome versus a simpler strategy of stenting only the parent vessel.

The intrinsic characteristics of a stent including stent length may affect both procedural success and long-term outcome. The present study evaluated the immediate and follow-up results after implantation of the short and long NIR stent and compared these results with the Palmaz-Schatz stent. Between July 1995 and December 1996, stenting with a 16-mm NIR stent (NIR-16), a 32-mm NIR stent (NIR-32), or a Palmaz-Schatz stent (PS) was performed in 68, 57, and 155 lesions, respectively. There were no significant differences in the incidences of delivery failure (PS, 2.6%: NIR-16, 4.4%; NIR-32, 5.3%; p = NS) and procedural success (PS, 92%; NIR-16, 93%; NIR-32, 93%; p = NS) among the 3 groups. The reference vessel diameter was smaller in lesions with a 32-mm NIR stent than in those with a Palmaz-Schatz stent (PS, 3.14 ± 0.58, NIR-16, 3.00 ± 0.50; NIR-32, 2.90 ± 0.47 mm; p

The results over a mean period of 2 years of successful percutaneous transluminal coronary angioplasty (PTCA) in 100 consecutive patients with chronic total coronary occlusion were compared with those in 100 consecutive patients whose PTCA was unsuccessful. The groups were comparable in terms of gender, age and arteries attempted. A control angiography in the group with successful PTCA was performed in 62 patients and showed a restenosis in 28 (45%). Repeat PTCA was performed in 21 versus 1 patient with failed PTCA (p less than 0.0001). At follow-up, in the group with successful PTCA, there were 57 symptom-free patients versus 26 patients in the group with failed PTCA (p less than 0.0001). Coronary artery bypass surgery was performed in 7 versus 37 patients (p less than 0.0001), and there were 5 versus 3 deaths (difference not significant), respectively. In the group with successful PTCA, 27 of 82 patients (33%) had positive stress test results, compared with 49 of 85 patients (58%) in the group with unsuccessful PTCA (p less than 0.001). The double product (beats/min x mm Hg/100) in patients with successful PTCA improved from 247 +/- 57 before PTCA to 277 +/- 61 (p less than 0.001) at follow-up, whereas it did not significantly change in patients with failed PTCA. The work load (W) in patients with successful PTCA improved from 95 +/- 34 before PTCA to 124 +/- 40 at follow-up (p less than 0.001). In patients with failed PTCA, work load improved less significantly, from 98 +/- 37 before PTCA to 108 +/- 34 at follow-up (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Objectives. This study attempted to analyze immediate and long-term angiographic and clinical results of coronary stent implantation for restenosis in a consecutive group of patients. Background. The rate of stent utilization in patients with coronary artery disease has increased exponentially in recent years. There are many unanswered questions about the use of stenting in patients with restenosis, particularly with respect to late clinical and angiographic results. Methods. A total of 159 stents were implanted in 128 consecutive patients with 139 lesions (mean 1.3 stents/patient). A technique of optimal stent expansion was used in all patients, and intravascular ultrasound guidance with no subsequent anticoagulation was performed in 41 patients. Results. Stent implantation was successful in 126 patients (98%). Four patients (3.1%) had complications (in two after successful stenting): death in one, emergency bypass surgery operation in two and subacute stent thrombosis in one. Stents were implanted with a final balloon size (mean ± SD) of 3.5 ± 0.5 mm and a mean maximal pressure of 11 ± 4 atm (range 8 to 20). Angiographic restenosis occurred in 27 patients (25%). Regression analysis on clinical and angiographic variables for prediction of restenosis showed no statistical significance for any variable. Late events occurred in 23 patients (19%). The actuarial survival rate was 98% at 1 year and at 3 years, and the event-free survival rate including freedom from repeat angioplasty for restenosis was 95% and 76%, respectively. Conclusions. The late angiographic outcome, restenosis rate and total clinical events are favorable for selected patients undergoing stent implantation for the indication of restenosis.

Recently, the safety of intravascular ultrasound (IVUS) guided stent implantation without subsequent anticoagulation has been established in 623 consecutive patients. The total incidence of stent thrombosis (l3 weeks) and bleeding complications is l1%. This new method (N) generally requires 2 days hospital stay. The traditional method (T) requires 7 days hospital stay to stabilize the anticoagulation regimen after stenting. Hospital charge for the (T) and (N) method was retrospectively analyzed for single Palmaz-Schatz coronary stent implantation. 20 consecutive patients with (T) before Jan 1, 1993 and 20 consecutive patient after Jan 1, 1994 with (N) were compared. Patient age, gender, procedure time, procedure cost, hospitalization duration (days), total charge (procedure, hospital and physician) and stent thrombosis (l1 month) were compared. Stenting Method Traditional New P value Age (Year) 58 ± 7 55 ± 7 0.44 Male (%) 19 (95%) 16 (80%) 0.18 Procedure Time (hr) 1.5 ± 0.5 1.3 ± 04 0.19 Procedure Cost ($) 8.513 ± 1.260 9.646 ± 3.129 0.18 Total Charge ($) 14.306 ± 2.494 11.733 ± 3.888 0.03 Hospitalization (days) 8 ± 2 2 ± 2 0.0001 Subacute Thrombosis 0 0 ns Conclusions The new method: (1) may increase the procedure cost because IVUS and, sometimes, an extra balloon were required to optimize stent expansion. (2) provided a significant reduction in the duration of hospitalization. 3) decreases hospital stay and eliminates the expense of monitoring for anticoagulation resulting in a significant reduction in total charges to the patient.

Intracoronary Ultrasound Observations During Stent Implantation Shigeru Nakamura, MD; Antonio Colombo, MD; Antonio Gaglione, MD; Yaron Almagor, MD; Steven L. Goldberg, MD; Luigi Maiello, MD; Leo Finci, MD; Jonathan M. Tobis, MD T he Palmaz-Schatz stent has been used success- fully to improve primary angioplasty results, to treat large coronary dissections, or to prevent impending closure of the lumen.-1-5 The determination of successful stent implantation is based on the angio- graphic appearance. However, angiographic projection imaging may not reveal the three-dimensional geometry that is necessary to appreciate full expansion of a cylindrical meshwork device such as the intracoronary stent. Intravascular ultrasound (IVUS) imaging has the advantage of providing detailed cross-sectional images from within the vessel lumen, allowing better evaluation of stent expansion.16-21 Based on angiographic assess- ment, it has been recommended to overdilate the ste- nosis about 10% greater than the reference vessel diameter.1 There is no quantitative guideline for IVUS assessment of successful stent implantation. The pur- pose of this study was to compare the observations of IVUS with standard angiography after stent implanta- tion and to develop recommendations for guiding stent implantation by IVUS. Methods Population and Stent Type The study population consisted of 63 consecutive patients who underwent Palmaz-Schatz stent insertion for native cor- onary arteries and received IVUS imaging at two institutions from January 1, 1993, to April 16, 1993. There were 55 men and 8 women. The mean patient age was 58.6±9.6 years. All patients had coronary artery stenosis with objective evidence of ischemia. Of the 65 lesions treated, the indications for stent insertion were elective implantation in 60 (92%) and emer- gency implantation in 5 (8%). Emergency stent deployment was defined as the presence of a large dissection with threat- ened closure after coronary angioplasty, as evidenced by chest pain and ischemic ECG changes. The target lesion was in the left anterior descending coronary artery (LAD) in 40 lesions, the left circumflex artery (LCx) in 10 lesions, the right coronary artery (RCA) in 14 lesions, and the left main artery in 1 lesion. A standard-length (15 mm) Palmaz-Schatz stent (Johnson and Johnson Interventional Systems) was used in 12 lesions (18%). A short version (7 mm) of the Palmaz-Schatz stent was made by cutting the articulation site22 and was used in 48 lesions (74%). A 10-mm-long biliary Palmaz stent was Received October 8, 1993; revision accepted November 16, From Centro Cuore Columbus (A.C., Y.A., L.M., L.F.), Milan, Italy; Villa Bianca and University of Bari (A.G.), School of Medicine, Bari, Italy; and the Division of Cardiology (S.N., S.L.G., J.M.T.), University of California Irvine. Correspondence to Antonio Colombo, MD, Centro Cuore Co- lumbus, Via Buonarotti 48, 20145 Milan, Italy. inserted in 10 lesions (15%). One stenosis was treated with a 10-mm renal Palmaz stent. The biliary and renal stents were used in heavily calcified lesions because of the additional strength of these larger devices. A single stent was implanted in 18 lesions (28%), and multiple stents were used in 47 lesions (72%). Anticoagulation All patients received aspirin 325 mg and a calcium channel antagonist before stent implantation. Heparin (10 000 U) was administrated intra-arterially at the beginning of the proce- dure and was followed by intravenous infusion to maintain the activated clotting time .300 seconds. Low-molecular-weight dextran 40 (10%) was administrated (100 mLIhr for 2 hours) and continued at 50 mIlhr for a total dose of 1 L. The sheaths were pulled 1 day after the procedure. Patients were main- tained on a heparin infusion for 4 to 5 days until a therapeutic warfarin dose was achieved with a prothrombin time between 16 and 18 seconds. Patients stayed in the hospital for 7 days after the procedure. Dipyridamole and sodium warfarin were continued for 2 months. Insertion Procedure When the lesion was severe, predilatation was performed with a 2.0-mm balloon using standard percutaneous coronary angioplasty techniques. All stents were manually mounted on a balloon that matched the angiographic reference lumen diameter. The stent was then overdilated with a balloon approximately 0.5 mm larger than the reference lumen diam- eter. To avoid balloon inflation outside of the stented segment of the vessel, a 9-mm-long balloon (Short Speedy, Schneider Europe) was used for final dilatation. The final dilatation was performed at higher pressures, if necessary. The procedure end point was achieved when the operator determined that maximal stent expansion had occurred based on the angiographic evidence of a step up into the stented area and a step down into the distal unstented segment. Ordinarily, the procedure would be terminated at this point, but for the purpose of this study, IVUS imaging was then performed using a 3.9-F monorail system with a 25-MHz ultrasound transducer (Interpret Catheter, InterTherapy/CVIS). The imaging cathe- ter was positioned under fluoroscopic guidance distal to the stent, and images were recorded continuously as the catheter was withdrawn manually through the stented segment. After the stented area was interrogated with a single pullback, the catheter was repositioned to identify the tightest segments within the stented portion. If the operator and ultrasound reviewer believed that there was a possibility to improve stent expansion, further balloon dilatations were performed using a larger balloon or higher pressure. The initial concept was to obtain a lumen cross-sectional area (CSA) approximately 70% of the expected CSA of the chosen balloon. IVUS imaging and balloon dilatation were repeated until a satisfactory lumen area and uniform expansion were achieved or no further improvement could be obtained. Downloaded from http://circ.ahajournals.org/ at CONS CALIFORNIA DIG LIB on October 10, 2015

To assess the effects of coronary angioplasty in patients with severe left ventricular dysfunction, the results of procedures, performed between 1987 and 1991, in 100 patients (90 male) with left ventricular functionor = 0.35 (range, 0.20 to 0.35) and anginal symptoms were analyzed. Mean age was 62 +/- 10 years (range, 38 to 85 years). Ninety-five patients had previous myocardial infarction and 27 patients had previous coronary artery bypass grafting. Unstable angina was present in 81 percent of patients. Single-vessel disease was present in 6 patients, double vessel was present in 31 patients, and triple-vessel disease was present in 63 patients. Percutaneous transluminal coronary angioplasty (PTCA) was attempted on 164 vessels, 27 of these with chronic total occlusion. The overall angiographic success rate was 84 percent. Myocardial infarction occurred in four patients, six patients underwent urgent coronary bypass surgery, and seven patients died of cardiac causes. There was a 9 percent incidence of total in hospital mortality. Major complications were significantly more frequent in patients with triple-vessel disease. Clinical success was achieved in 75 patients, 55 of these with incomplete revascularization. Long-term follow-up (mean, 19 +/- 7 months) was available in all patients with clinical success. Thirteen patients had repeated PTCA, 8 patients had coronary surgery, and 13 patients died. In conclusion, in patients with severe left ventricular dysfunction, acute complications and late mortality rate are high. Patients with triple-vessel disease are a higher risk subset and have no long-term benefits by PTCA.

The coronary stents implantation into each vessel of a bifurcational lesion (“kissing” stents) in two patients is reported. The first patient had two short “kissing” stents implanted in an ostial lesion of the left anterior descending and the intermediate branch. The second patient had successful “kissing” stents implantation in the bifurcational lesion of the left main coronary artery.© 1993 Wlley-Liss, Inc

The aim of this study was to determine feasibility, safety and yield of early stress tests after successful coronary angioplasty. In 351 consecutive patients with an early stress test performed within 3 days after successful coronary angioplasty, no cardiac or puncture site complications occurred. Seventeen percent of the stress tests remained positive after successful coronary angioplasty. An angiographic explanation, based on the data collected at the time of the angioplasty procedure, was present in 82% of the cases. Positive early stress tests typically only prompted modifications of the drug regimen.

We studied a group of 47 patients greater than or equal to 75 years old. The mean age was 77 +/- 1.5 years and there were 28 (60 percent) male patients. Multivessel disease was present in 72 percent. Angioplasty was successful in 93 percent of 90 stenoses and in 30 percent of ten total occlusions. Single vessel angioplasty was done in 53 percent of patients, double vessel in 28 percent and triple vessel in 19 percent. Incomplete or absent revascularization was present in 47 percent and 9 percent, respectively. Primary clinical success was accomplished in all patients with single vessel disease; in 85 percent of patients with double vessel disease, and in only 52 percent of patients with triple vessel disease. Complications were highest in patients with triple vessel disease: 14 percent mortality and 5 percent emergency CABG. The follow-up at one year showed 91 percent survival. The PTCA is a valid alternative method of revascularization in elderly patients with single and double vessel disease. The results in triple vessel disease are less encouraging.

We studied 100 patients who had coronary implantation of Palmaz-Schatz stents in our institution from November 1989 until March 1991. A total of 126 standard and 6 short stents were implanted. The patients' mean age was 58 ± 5 years, and 97 were males. The indications were lesions with high risk of restenosis (29 patients), restenosis (27 patients), suboptimal result of angioplasty (24 patients), dissection (16 patients), and recanalized chronic total occlusion (6 patients). In 17 patients a brachial cut-down approach was used. Stents were correctly placed in 98 patients. Stent related complications occurred in 9 patients: major ischemic complications in 7 patients (acute myocardial infarction in 2 patients, emergency bypass surgery in 3 patients and emergency angio-plasty in 2 patients); in 3 of these patients there was a subacute closure of the stent and in 2 patients there were delivery problems. Vascular complications at the site of arterial puncture occured in 3 patients (some patients had more than one complication). A learning curve was observed. There was a decrease in the complication rate with the higher number of patients treated: 28% for the first 50 patients and 6% for the last 50 patients. Clinical follow-up was available in all patients. Of the 92 patients eligible for follow-up (7 ± 2 months), 69 patients were asymptomatic and 23 had recurrence of angina: 19 patients for stent restenosis and 4 patients for coronary artery disease progression. Follow-up angiogram was done in 79/92 (86%) patients: 21 had restenosis (27%). Restenosis rate was higher in patients with multiple stents 40% (6/15) than with the single stent 23% (15/64), and when the indications were for dissection 35% (6/17). These differences did not reach statistical significance. The global incidence of restenosis appears to be lower when compared to balloon coronary angloplasty, although there is no garantee these populations are comparable. Stenting seems to be a good alternative to coronary angioplasty in lesions which are not considered ideal for the balloon dilatation and to treat occlusive dissections. The use of multiple and partial overlapping stents is associated with a high restenosis rate. These impressions need to be tested in a large, randomized, multicenter study. © 1992 Wiley-Liss, Inc.

The Wiktor coronary stent has been implanted in 82 lesions in 68 patients. The indication for stent implantation was 49 elective (57%), 10 threatened closure (12%), 9 SUboptimal PTCA (11%), 7 chronic total occlusion (9%), 4 restenosis (5%), and 3 acute occlusion (4%). Vessel distribution was 39 RCA (48%), 31 LAD (37%) and 12 LCX (15%). Successful stent implantation was achieved in 77 lesions (94%). Average Wiktor stent per lesion was 1.4 ± 0.8 (range 1 to 4). More than one stent was used in 53 patients (69%). Lesion length was 14.8 ± 9.7 mm. Final balloon/vessel ratio was 1.03 ± 0.15. Maximum inflation pressure was 16 ± 3 atmospheres. There were 5 lesions that required an additional Palmaz-Schatz stent inside the Wiktor to reinforce the lumen support. Mild stent structural deformity (expanded strut gap) was seen in 8 lesions. There were 5 stents with severe stent deformity due to shrinkage (n = 3) or uncoiling (n = 2). 59 patients (93%) with 72 lesions (88%) of were treated with only antiplatelet therapy after stent implantation with intravascular ultrasound guidance. There were 2 CABG due to stent severe stent deformity. One death was due to femoral artery occlusion with multiple organ failure. To date, 35 of an eligible 59 lesions (59%) received 4–6 months angiographic follow up (F/U). AG results Reference (mm) Lesion (mm) % stenosis Baseline 3.18 ± 0.42 0.73 ± 0.49 73 ± 16 Post stent 3.20 ± 0.36 2.98 ± 0.39 6 ± 10 F/U 297 ± 0.49 2.02 ± 0.73 28 ± 26 There was one stent thrombosis that occurred 8 days after the stent procedure and 5 days after antiplatelet therapy was inadvertently stopped. Wiktor stent restenosis by ≥ 50% diameter stenosis was present in 8 patients (23%). Conclusions (1) Short term results and restenosis rate after Wiktor stent implantation without subsequent anticoagultion is encouraging. (2) Mild or significant structural deformity was found in 13 (16%) of stents.