Restenosis rate after intravascular ultrasound-guided coronary stent implantation

This study was designed to test the hypothesis that patients fulfilling intravascular ultrasound (IVUS) criteria for optimal coronary stent implantation show a reduction in the restenosis rate at 6 months. IVUS guidance for stent dilation may be associated with faciliated stent implantation and an increased acute luminal gain, but it has not yet been determined, whether and to what extent this procedure is associated with a reduction in the restenosis rate. IVUS-guided optimization of Palmaz-Schatz stent placement was performed in 125 consecutive patients, 64 of whom fulfilled IVUS-criteria for optimal stent placement. Another 125 patients served as the non-IVUS control group. In 107 patients (86%) of the non-IVUS control group and 105 patients (84 %) of the IVUS group, angiographic follow-up was performed. The IVUS group of patients revealed a significantly lower restenosis rate of 20.9% as compared with 29.9% in the control group (P = 0.033). Patients that met IVUS criteria for optimal stent placement had a larger minimal lumen diameter immediately after stent implantation (3.13 ± 0.44 vs. 2.95 ± 0.47 mm; P = 0.045) and at 6-month follow-up (2.23 ± 0.78 vs. 1.87 ± 0.76 mm; P = 0.019) as well as a significantly lower restenosis rate (13.5% vs. 28.3%; P = 0.038) as compared with patients that did not fulfil these criteria. Our data suggest that patients fulfilling IVUS criteria for optimal stent placement demonstrate a reduced risk for the development of restenosis. Thus, IVUS investigation identifies factors predictive of restenosis after coronary stent placement. Cathet. Cardiovasc. Diagn. 44:380–386, 1998. © 1998 Wiley-Liss, Inc.     

Impact of intravascular ultrasound‐guided percutaneous coronary intervention on long‐term clinical outcomes in a real world population

Objectives : To compare long‐term clinical outcomes between intravascular ultrasound (IVUS)‐guided and angiography‐guided percutaneous coronary intervention (PCI) in a large “real world” registry. Background : The impact of IVUS‐guided PCI on clinical outcomes remains unclear. Methods : Between January 1998 and February 2006, 8,371 patients who underwent IVUS‐ (n = 4,627) or angiography‐ (n = 3,744) guided PCI were consecutively enrolled. Three‐year clinical outcomes were compared after adjustment for inverse‐probability‐of‐treatment weighting (IPTW) in the overall population and in separate populations according to stent type. Results : A crude analysis of the overall population showed that the 3‐year mortality rate was significantly lower in the IVUS‐guided group than in the angiography‐guided group (96.4% ± 0.3% vs. 93.6% ± 0.4%, log‐rank P < 0.001). When adjusted by IPTW, patients undergoing IVUS‐guided PCI remained at lower risk of mortality (hazard ratio [HR] 0.627; 95% CI 0.50–0.79, P < 0.001). Similarly, in the drug‐eluting stent (DES) population, the 3‐year risk of mortality was significantly lower in patients undergoing IVUS‐guided PCI (HR 0.46; 95% CI 0.33–0.66, P < 0.001). In contrast, IVUS‐guided PCI did not reduce the risk of mortality in the bare metal stent population (HR 0.82; 95% CI 0.60–1.10, P = 0.185). However, the risks of myocardial infarction (HR 0.95; 95% CI 0.63–1.44, P = 0.810), target vessel revascularization (HR 1.00; 95% CI 0.86–1.15, P = 0.944), and stent thrombosis (HR 0.82; 95% CI 0.53–1.07, P = 0.109) were not associated with IVUS guidance. Conclusions : IVUS‐guided PCI may reduce long‐term mortality when compared with conventional angiography‐guided PCI. This may encourage the routine use of IVUS for PCI in patients undergoing DES implantation. © 2012 Wiley Periodicals, Inc.     

旋磨术联合切割球囊成形术治疗冠状动脉重度钙化病变

目的血管内超声评价旋磨术联合切割球囊成形术治疗冠状动脉重度钙化病变的安全性及有效性。方法收集冠状动脉造影及血管内超声检查确认至少1处病变为高度钙化,并行旋磨术处理的冠心病患者80例,根据是否使用切割球囊分为单纯旋磨组34例和旋磨联合切割组46例。患者在支架置入前及置入后均行血管内超声检查,评价支架置入效果。结果单纯旋磨组与旋磨联合切割组最大钙化弧度分别为(215.88±21.81)°vs(226.55±21.59)°,钙化长度比为(0.72±0.06)vs(0.78±0.05),支架置入前最小管腔面积为(2.52±0.07)mm2 vs(2.46±0.09)mm2,2组比较差异无统计学意义(P>0.05)。支架置入后,旋磨联合切割组最小支架面积(6.12±0.37)mm2和即刻管腔获得面积(3.66±0.34)mm2,单纯旋磨组分别为(5.42±0.24)mm2和(2.90±0.24)mm2,2组比较差异有统计学意义(P=0.016)。2组术中并发症的发生比例比较,差异无统计学意义(P>0.05)。结论在冠状动脉重度钙化病变中,使用旋磨术联合切割球囊成形术可以获得更好的支架置入后效果。     

Stepwise intravascular ultrasound (IVUS) guidance of high-pressure coronary stenting does not result in an improved acute or long-term outcome: A randomized comparison to “final-look” IVUS assessment

The objective of this study was to evaluate the potential benefit of stepwise intravascular ultrasound (IVUS)-guided coronary stent deployment compared to angiographic stent implantation with final IVUS assessment only. Acute procedural success and 6-month angiographic follow-up were compared in both groups. Intravascular ultrasound was performed using a 20- or 30-MHz mechanically rotated catheter in 85 patients who were prospectively randomized to group A (n = 42; IVUS-guided) and group B (n = 43; angiography + final IVUS assessment). There was no difference in the number of stents implanted (1.5 ± 0.9 stents/lesion in group A and 1.3 ± 0.6 stents/lesion in group B), the duration of the procedure, or the amount of contrast medium used. Defined criteria of optimal stent deployment (stent apposition, stent symmetry, complete coverage of dissections, >90% in-stent lumen area/reference lumen area) were achieved in 54.2% in group A and 56.6% in group B (NS). Angiographic follow-up was 87.1% at 6 ± 2 months, and clinical follow-up was 100% at 8 ± 1 months. There was no significant difference in restenosis rate (33.3% vs. 34.9%) applying a binary >50% diameter stenosis criterion for both groups. There was no significant difference in minimal in-stent lumen area at both baseline (7.91 ± 2.64 mm² vs. 7.76 ± 2.21 mm²) and follow-up (5.84 ± 2 mm² vs. 5.52 ± 1.87 mm²). With regard to immediate procedural lumen gain and rate of restenosis, multiple IVUS examinations during the procedure showed no advantage compared to final IVUS assessment only. Cathet. Cardiovasc. Intervent. 46:135–141, 1999. © 1999 Wiley-Liss, Inc.     

Optical coherence tomography and intravascular ultrasound imaging of bioabsorbable magnesium stent degradation in porcine coronary arteries

BackgroundAbsorbable metallic stents (AMS) composed of magnesium alloy were designed to complete degradation within 90–120 days. Among the potential advantages of these stents, when compared to conventional stents, are the elimination of late stent thrombosis, chronic inflammation, and artifacts during noninvasive imaging.MethodsMagnesium-based AMS were deployed in juvenile domestic pig coronary arteries. Angiography, optical coherence tomography (OCT), and intravascular ultrasound (IVUS) were performed before and after implant and then at 28 days and 3 months following stenting. The animals were sacrificed at 28 days or 3 months following stent implantation. Stented vessels were harvested and analyzed by histomorphometry.ResultsOver time, OCT, IVUS, and histologic images revealed a progressive degradation of the stents. Mean stent strut width in the OCT images after implantation was 0.24±0.032 mm, then decreased to 0.12±0.007 mm (P<.0001) at 28 days and to 0.151±0.032 mm at 3 months (P<.0001 vs. implant, P=.078 vs. 28 days).ConclusionMagnesium-based AMS degrade over a 3-month time period in a porcine model. Its structure is not apparent by angiography but is well-visualized by OCT and IVUS. OCT allowed quantitative assessment of stent degradation.     

Effect of balloon inflation time on expansion of sirolimus-eluting stent

There is little information about the relationship between balloon inflation time and sirolimus-eluting stent (SES) expansion. In this randomized intravascular ultrasound (IVUS) study, 92 de novo lesions in native coronary arteries that underwent SES implantation were enrolled. Sirolimus-eluting stent was implanted using an inflation pressure of 14 atm. Stent balloon was gradually inflated until 14 atm in 10 s. In the short inflation group, it was deflated immediately after an image of the balloon inflated at 14 atm was taken. Stent balloon inflation lasted 60 s in the long inflation group. Intravascular ultrasound was then performed. The long balloon inflation resulted in a larger stent cross-sectional area (4.9 ± 1.6 mm² vs 4.3 ± 1.4 mm², P < 0.05) and expansion (71% ± 13% vs 60% ± 13%, P < 0.001) compared to the short balloon inflation, although stent expansion was relatively low in both groups. The relatively longer balloon inflation time using an inflation pressure of 14 atm results in better SES expansion. However, in the majority of lesions, adequate stent expansion is not achieved even using long balloon inflation, if it is inflated at 14 atm.     

Intracoronary ultrasound before coronary interventions: A prospective comparison of two different catheters

Intravascular ultrasound (IVUS) provides unique information about the coronary arterial wall that can be used to guide transcatheter therapy. In this prospective study, two different IVUS systems were compared with respect to feasibility of imaging before intervention and angiographic changes induced by the simple advancement of the catheter across the lesion. Eighty-five patients (mean age 59 ± 10 yr, 11 female) were studied with IVUS before intervention. In 34 patients, a 4.8F (1.6-mm) IVUS catheter was used (Group I), whereas in the remaining 51 patients a 3.5F (1.2-mm) IVUS catheter was used (Group II). Quantitative angiography was performed before and after the IVUS study to determine potential changes in lumen diameter. Clinical and angiographic characteristics were similar in the two groups. A successful IVUS interrogation of the target lesion was obtained more frequently in Group II (45/51 (88%) vs. 19/34 (56%) patients, P < 0.01). After the IVUS study, a change in minimal lumen diameter was seen in Group I (baseline 0.84 ± 0.2 vs. Final 1.17 ± 0.2 mm, P < 0.001) and Group II patients (baseline 0.80 ± 0.3 vs. final 1.03 ± 0.4 mm, P < 0.01). In the 64 lesions successfully crossed, the absolute gain in lumen diameter was significantly higher in Group I (0.40 + 0.2 vs. 0.23 ± 0.2 mm, P < 0.05). In addition, an inverse correlation was found between baseline minimal lumen diameter and the absolute lumen gain induced by the IVUS study in Group I (r = −0.47, P < 0.05) but not in Group II patients (r = −0.16, NS). Neither angiographic nor echogenic lesion characteristics were associated with the change in lumen diameter. When multivariate analysis was applied, catheter size was the only independent predictor of lumen gain induced by IVUS after adjustment. Thus, the advancement of IVUS catheters across severe coronary lesions induces significant angiographic changes consistent with plaque remodeling and a Dotter effect. The use of smaller catheters not only allows a higher number of lesions to be studied before intervention, but also lessens the mechanical disruption of the plaque, yielding a more accurate and veracious picture of baseline plaque characteristics. Cathet Cardiovasc Diagn 40:33–39, 1997. © 1997 Wiley-Liss, Inc.     

Temporary arterial stenting: Comparison to permanent stenting and conventional balloon injury in a rabbit carotid artery model

The objective was to assess the arterial wall response to temporary stenting with a removable nitinol stent in comparison with permanent stenting and balloon injury at 28 days in the rabbit carotid artery. Restenosis remains an important limiting factor after the implantation of permanent metallic stents and balloon angioplasty. We have developed a temporary nitinol stent that uses a bolus injection of warmed saline to collapse the stent for percutaneous removal. Vascular changes related to the thermal saline bolus injection required to remove a nitinol implanted stent were assessed in 12 rabbit carotid arteries at 7 and 28 days postinjection. Nitinol stents, inflated to 3.0 mm diameter, were implanted for 3 days (n = 6) and histology and quantitative histomorphometry examined at 28 days. Results were compared with permanently implanted stents (n = 5) and balloon injury (n = 9). Dual bolus injection of 10 ml at 70°C created an acute necrotizing injury and chronic neointimal proliferation, whereas injections of 5 ml at 63°C were minimally injurious. Temporary stenting resulted in the least neointimal proliferation measured by the intima to media ratio (0.22 ± 0.10 vs. 1.59 ± 0.31 for permanent stenting and; 0.49 ± 0.14 for balloon injury; P < 0.001). Temporary stenting maintained a significantly larger lumen than balloon (1.53 ± 0.72 mm² vs. 0.64 ± 0.14 mm²; P < 0.001), which could not be explained by absolute changes in intimal cross sectional area (0.14 ± 0.07 mm² vs. 0.21 ± 0.06 mm² respectively; P = 0.33). Temporary stenting resulted in a relatively larger vessel area within the external elastic lamina than with balloon (2.28 ± 1.06 mm² vs. 1.30 ± 0.18 mm²; P = 0.007). The thermal stent recovery process can create necrotizing vascular injury and neointimal proliferation at higher temperatures and injectate volumes. Stent removal after 3 days using 63°C saline bolus injection results in less neointimal proliferation than with permanent stents or balloon injury. In comparison to balloon injury, temporary stenting also may have a long-lasting beneficial effect on vessel recoil and remodeling, resulting in larger lumen size after stent removal. Cathet. Cardiovasc. Diagn. 41:85–92, 1997. © 1997 Wiley-Liss, Inc.     

Impact of intravascular ultrasound guidance in stent deployment on 6-month restenosis rate: a multicenter,randomized study comparing two strategies—with and without intravascular ultrasound guidance

Objectives. We aimed to investigate the impact of intravascular ultrasound (IVUS)-guided stent implantation on the 6-month restenosis rate, which has not yet been fully established in randomized trials.Background. The 6-month angiographic restenosis rate was compared in patients with symptomatic ischemic heart disease who were randomly allocated to angioplasty and stent deployment, with versus without IVUS guidance.Methods. After successful stent implantation, patients were randomized into two groups: Group A had no further dilation, and Group B had additional balloon dilation until achievement of IVUS criterion for stent expansion. The study group consisted of 164 patients, assuming a 50% reduction of the restenosis rate in Group B (15% vs. 30%) (alpha = 10%, beta = 20%).Results. We enrolled 155 patients. Overdilation was carried out in 31 (39%) of 79 Group B patients, with the IVUS criterion being achieved in 63 (80%) of 79. No significant difference was observed in the minimal luminal diameter (MLD), but the stent lumen cross-sectional area (CSA) was significantly larger in Group B (mean ± SD) (7.16 ± 2.48 vs. 7.95 ± 2.21 mm², p = 0.04). At 6 months, there was no significant difference in the restenosis rate, (28.8% [21 of 73] in Group A vs. 22.5% [16 of 71] in Group B, p = 0.25), but according to the observed difference in the restenosis rate, the power of the study was only 40%. The difference in MLD was also nonsignificant (1.60 ± 0.65 mm in Group A vs. 1.70 ± 0.64 mm in Group B, p = 0.20), whereas the lumen CSA was 20% larger in the IVUS-guided group (4.47 ± 2.59 vs. 5.36 ± 2.81 mm², p = 0.03). Lumen CSA was the only predictor of restenosis by multivariate logistic regression analysis.Conclusions. A nonsignificant 6.3% absolute reduction in the restenosis rate and a nonsignificant difference in MLD were observed in this study. Nonetheless, we still cannot rule out a beneficial effect of IVUS guidance, although this may have gone undetected owing to a lack of statistical power. A significant increase was observed in immediate and 6-month lumen size, as detected by IVUS, indicating that ultrasound guidance in stent deployment may be beneficial.     

Stent implantation for relief of pulmonary artery stenosis: Immediate and short-term results

Our objective was to assess the immediate and short-term results of stent implantation to relieve pulmonary artery stenosis (PAS). Thirty-seven patients underwent an attempt at stent implantation at a median age of 7.0 years (range, 0.8–31.4 years) and a median weight of 20.5 kg (range, 7.4–85 kg). Twenty-two patients had previous tetralogy of Fallot repair. A total of 55 stents were implanted successfully in 36 patients. The peak systolic gradient across the stenotic segment decreased from a mean of 43 ± 20.4 mmHg prestent to 13 ± 13.9 mmHg (P < 0.001) poststent. The diameter of the narrowest segment increased from a mean of 4.8 ± 1.6 mm to 10.5 ± 2.6 mm (P < 0.001). The right ventricular-to-aortic mean systolic pressure ratio decreased from 0.74 ± 0.2 to 0.52 ± 0.19 (P < 0.001). Complications included balloon rupture prior to full stent expansion in 4 patients (in 2 patients the stent was positioned in the superior vena cava, and in 2 in the inferior vena cava), distal migration of a stent which was successfully retrieved at surgery 1 mo later in 1 patient, and tethering of the stent to the balloon requiring surgical removal in 1 patient. One patient died several hours after stent placement. Sixteen patients underwent repeat catheterization at a mean follow-up interval of 0.9 ± 0.5 years (range, 0.2–2.0 years). The mean gradient across the stent for these 16 patients was 26.7 ± 19.8 mmHg, and there was no change in the mean diameter (9.4 ± 3.2 mm). Two patients developed stenosis related to neointimal proliferation at the stent site which was redilated successfully. In conclusion, stent implantation is generally safe and effective in relieving PAS. © 1996 Wiley-Liss, Inc.     

Improving results of bailout coronary stenting after failed balloon angioplasty

Stent implantation can be a valuable alternative to emergent bypass surgery to treat established or threatening abrupt closure following coronary balloon angioplasty. To evaluate several sequentially introduced changes in our practice of bail-out stenting, we compared the first (group I) and second half (group II) of our single center experience (n = 88). Use of bailout stenting increased over time (2% of all angioplasty procedures in group I vs. 6% in group II, P < 0.001), more often to prevent rather than to reverse abrupt closure. Technical success of stent implantation was unchanged (95% vs. 93%), and there was a decreasing trend for stent thrombosis (14% vs. 5%), in-hospital death (5% vs. 2%), Q-wave myocardial infarction (9% vs. 7%), and requirement for surgery (9% vs. 7%). The incidence of non-Q-wave myocardial infarction (29% vs. 7% P < 0.01), bleeding complications (27% vs. 7% P < 0.01), and hospital stay duration (11 ± 11 vs. 8 ± 5 days P < 0.05) decreased. Our data suggest that coronary stent implantation is currently an effective stand-alone bailout procedure for a large majority of failed angioplasty procedures. © 1994 Wiley-Liss,Inc..     

Systemic rapamycin without loading dose for restenosis prevention after coronary bare metal stent implantation

Objectives : The aim of this study was to assess the role of short oral administration of rapamycin, without loading dose, in the reduction of restenosis rate after bare metal stent implantation. Background : Previous studies suggest that the administration of oral rapamycin reduces angiographic restenosis after bare metal stent implantation. Methods : This was prospective, open‐label study of 80 patients randomized to either oral rapamycin (2 mg/day for 30 days, starting within 24 hr of stent implantation) or no therapy after implantation of a coronary bare metal stent. The primary study end point was incidence of angiographic binary restenosis and late loss at six months. The secondary end points were target lesion revascularization (TLR), target vessel revascularization (TVR), and incidence of major adverse cardiovascular events (MACE) at 6 months. Results : Angiographic follow up was completed in 72/80 (90%) of patients. In the rapamycin group, the drug was well tolerated (22.5% minor side effects) and was maintained in 100% of patients. At six months, the in‐segment binary restenosis was 10.5% in rapamycin group vs. 51.4% in no‐therapy group, P < 0.001) and the in‐stent binary restenosis was 7.9% in rapamycin group vs. 48.7% in no‐therapy group, P < 0.001. The in‐segment late loss was also significantly reduced with oral therapy (0.29 ± 0.39 vs. 0.86 ± 0.64 mm, respectively, P < 0.001). Similarly, after six months, patients in the oral rapamycin group also showed a significantly lower incidence of TLR and TVR (7% vs. 22.7%, respectively, P = 0.039) and MACE (7% vs. 22.7%, respectively, P = 0.039). Conclusions : This study showed that the administration of oral rapamycin (2 mg/day, without loading dose) during 30 days after stent implantation significantly reduces angiographic and clinical parameters of restenosis. © 2009 Wiley‐Liss, Inc.     

Serial intravascular ultrasound analysis comparing double kissing and classical crush stenting for coronary bifurcation lesions

Background : Compared with the classical crush, double kissing (DK) crush improved outcomes in patients with coronary bifurcation lesions. However, there is no serial intravascular ultrasound (IVUS) comparisons between these two techniques. Objectives : This study aimed to analyze the mechanisms of the two crush stenting techniques using serial IVUS imaging. Methods : A total of 54 patients with IVUS images at baseline, post‐stenting and eight‐month follow‐up were classified into classical (n = 16) and DK (n = 38) groups. All patients underwent final kissing balloon inflation (FKBI). Unsatisfactory kissing (KUS) was defined as the presence of wrist or >20% stenosis during FKBI at the side branch (SB) ostium. The vessels at bifurcation lesions were divided into the proximal main vessel (MV) stent, the crushed segment, the distal MV stent, the SB ostium and the SB stent body. Results : KUS and incomplete crushing were commonly observed in the classical group (62.5%, 81.3%), compared with DK group (18.0%, 39.5%, P < 0.001 and P = 0.004). The post‐stenting stent symmetry in the classical group was 71.85 ± 7.69% relative to 85.93 ± 6.09% in DK group (P = 0.022), resulting in significant differences in neointimal hyperplasia (NIH, 1.60 ± 0.21 mm² vs. 0.85 ± 0.23 mm², P = 0.005), late lumen loss (1.31 ± 0.81 mm² vs. 0.55 ± 0.70 mm², P = 0.013), and minimal lumen area (MLA, 3.57 ± 1.52 mm² vs. 4.52 ± 1.40 mm^2, P = 0.042) at the SB ostium between two groups. KUS was positively correlated with the incomplete crush and was the only predictor of in‐stent‐restenosis (ISR) at the SB ostium. Conclusion : DK crush was associated with improved quality of the FKBI and larger MLA. KUS predicted the occurrence of ISR. © 2011 Wiley Periodicals, Inc.     

Impact of intravascular ultrasound findings on long-term patency after self-expanding nitinol stent implantation in the iliac artery lesion

Although intravascular ultrasound (IVUS) predictors of stent patency for the coronary artery lesion have been established, little is known about IVUS predictors of stent patency for the aorto-iliac artery lesion. We analyzed 154 lesions of 122 patients who underwent stent implantation for iliac artery lesions. Quantitative and qualitative IVUS analyses were performed for pre- and post-procedural IVUS imaging in all lesions. Target lesion revascularization (TLR) was defined as clinically driven revascularization with >50 % angiographic stenosis of the target lesion. The mean follow-up period was 39 ± 16 months. TLRs were performed in 13 lesions (8.4 %). Post-procedural minimum stent area (MSA) was significantly smaller in the TLR group compared to the no-TLR group (16.0 ± 5.8 vs. 25.6 ± 8.5 mm², p < 0.001). Stent edge dissection was frequently observed in the TLR group compared to the no-TLR group (53.8 vs. 24.1 %, p = 0.04). Multivariate analysis revealed that post-procedural MSA (OR = 0.76, p < 0.01) and stent edge dissection (OR = 10.4, p < 0.01) were independent IVUS predictors of TLR. Receiver-operating characteristic analysis identified post-procedural MSA <17.8 mm² as the optimal cut-point for the prediction of TLR (AUC = 0.846). Post-procedural MSA and stent edge dissection could predict long-term stent patency in the iliac artery lesion. Our results propose that adequate stent enlargement without edge dissection might be important to reduce TLR in the iliac artery lesion.     

Local delivery of a low molecular weight heparin following stent implantation in the pig coronary artery

Background: The low molecular weight heparin Reviparin reduces smooth muscle cell proliferation in cell culture experiments. Clinical studies with systemic application of the substance did not show a reduction of the incidence of restenosis following balloon angioplasty. Local delivery, by achieving higher local concentrations of the drug, may have the potential to decrease smooth muscle cell proliferation in the treated arterial segment. Objectives: The aim of this study was to investigate the effects of local delivery of reviparin following stent implantation in the pig coronary artery. Methods: A coronary stent was implanted in the LAD of 34 pigs. In the treatment group 5 ml reviparin was injected with the Infusasleeve catheter at a proximal pressure of 80 psi. After 28 days the animals were sacrificed. Quantitative morphometric analysis comprised the intimal area, medial area and the lumen. The extent of vessel injury and the intimal thickness were assessed separately for each stent strut region. The correlation of injury and neointimal thickness was analysed using linear regression. Results: There was no relevant difference in the extent of vessel injury (1.9 ± 0.7 vs. 1.6 ± 0.6), the neointimal areas (2.4 ± 0.9 vs. 2.4 ± 1.0 mm²) and the resulting stenosis (46 ± 18 vs. 47 ± 17%). The medial area was larger in the animals treated with local delivery (2.2 ± 0.4 vs. 1.6 ± 0.4 mm²; p < 0,01). The correlation of injury and neointimal thickness was comparable in both groups. In two animals the passage of the stent area with the delivery system resulted in stent dislocation and fatal subacute thrombosis. Conclusion: In this animal model, local delivery of reviparin with the Infusasleeve catheter did not result in a reduction of neointimal proliferation following stent implantation. Local delivery after stent implantation carries the risk of stent dislocation as a result of the passage with the delivery system. Received: 16 September 1999, Returned for revision: 14 October 1999, Revision received: 28 October 1999, Accepted: 14 December 1999     

Elective versus deferred stenting following subintimal recanalization of coronary chronic total occlusions

Subintimal tracking and re‐entry (STAR) technique has been described as a bailout strategy for coronary total occlusion (CTO) recanalization. However, the length of the dissected segment represents a major concern. The aim of this study is, to evaluate whether “deferred” stent implantation may limit the total stent length following STAR recanalization of CTO. All consecutive patients with CTO in a native coronary artery treated by successful STAR technique in our institution were included. In the first period (March 2004–December 2009) all procedures were completed with stent implantation (Elective Stent Group; n = 60). Thereafter (January 2010–June 2012) stent implantation was postponed until a scheduled (within 3 months) angiographic follow‐up (Deferred Stent Group; n = 69). The dissection length was 75 ± 37 mm in the Elective Stent Group and 83 ± 31 mm in the Deferred Stent Group (P = 0.22). In the Deferred Stent Group, at the angiographic follow‐up, the dissection length was significantly shorter than at the index procedure (40 ± 35 mm versus 83 ± 31 mm, P <0.001). The total stent length was significantly shorter in the Deferred Stent Group versus the Elective Stent Group (22 ± 33 mm versus 56 ± 28 mm; P < 0.001). At six‐month follow‐up, rate of cardiac death and myocardial infarction (6.7% vs 0; P = 0.049) and of stent thrombosis (5% vs 0%; P = 0.10) were higher in the Elective Stent Group. The present study suggests that deferring stenting implantation following STAR recanalization (1) limits the stent length and (2) is associated with a lower rate of objective endpoints. © 2014 Wiley Periodicals, Inc.     

Implantation of balloon-expandable stents for coarctation of the aorta: Implantation data and short-term results

We report the immediate results and the short-term follow-up in a group of selected patients with coarctation of the aorta who underwent endovascular stent implantation. Balloon-expandable stents were implanted in 6 patients (mean age 19.8 ± 5.1 years) with coarctation of the aorta (4 recurrent and 2 native) who underwent a total of 7 procedures (6 implantation and 1 further expansion). The systolic peak pressure gradient was decreased from 36.7 ± 16.9 to 13.3 ± 23.2 mm Hg (P < 0.005). There was a 66% increase in the mean coarctation diameter from 9.3 ± 1.7 to 15.6 ± 3.1 mm (P = 0.001) with the ratio of the coarctation to descending aorta diameter, measured at the level of the diaphragm, increasing from 0.49 ± 0.1 to 0.81 ± 0.2 (P < 0.005). The dilatation was successful in expanding the stent to an acceptable diameter in 5 of 6 patients. One patient underwent successful further expansion of a stent implanted 22 months previously. There were no immediate complications during balloon expansion and stent implantation. One patient suffered a femoral arterial bleed requiring surgical repair. There was one unrelated death. All patients were hypertensive (systolic blood pressure >140 mm Hg) prior to stent implantation. At mean follow-up of 8 months, 3 patients are normotensive. There was no recurrence of coarctation, aortic dissection, or aneurysm formation in the patients in whom stent implantation was successful. These findings indicate that balloon-expandable stent implantation for coarctation of the aorta in selected patients is a safe and effective alternative approach for relieving the obstruction with a low complication rate and no recoarctation at short-term follow-up. © 1996 Wiley-Liss, Inc.     

Stent redilation in canine models of congenital heart disease: Pulmonary artery stenosis and coarctation of the aorta

In a canine puppy model, pulmonary artery stenosis was created by banding the left pulmonary artery to 30–40% of its original diameter. Animals underwent right heart catheterization and angiography 1–2 mo later, and Palmaz P308 stents were implanted. Stent redilation was performed 3–5 mo later. One mo postredilation, the animals were restudied and sacrificed. Coarctations of the aorta were created by transverse aortic incision and longitudinal repair. P308 stent implantation was performed 2–3 mo later. Stent redilation was performed after 6–10 mo, and the animals were restudied and sacrificed 1–2 mo later. Stent implantation was performed in 6 puppies with pulmonary artery stenosis, as 2 animals developed postoperative pulmonary arterial hypoplasia, precluding stenting. The stenosis diameter increased from 4.8 ± 0.5 mm to 7.4 ± 0.6 mm (mean ± SE) following stenting (P = 0.005), and increased further to 9.2 ± 0.7 mm following redilation (P < 0.001). There were no significant vessel tears or ruptures. Coarctation stenting was performed in 8 animals. The coarctation was dilated from 5.8 ± 0.9 mm to 9.8 ± 0.6 mm (P < 0.001), and to 13.5 ± 0.5 mm at redilation (P = 0.002). Redilation could not be performed in 1 animal. Aortic rupture and death occurred in 2 of 7 animals at redilation. Stent implantation and redilation in experimental pulmonary artery stenosis appears safe and effective. Though stent implantation for coarctation of the aorta appears safe, there was a 28% aortic rupture rate at stent redilation in this model. © 1996 Wiley-Liss, Inc.     

Stent boost enhancement compared to intravascular ultrasound in the evaluation of stent expansion in elective percutaneous coronary interventions

Background

Stent underexpansion is a major risk factor for in-stent restenosis and acute in-stent thrombosis¹Intravascular ultrasound (IVUS) is one of the standards for detection of stent underexpansion (de Feyter et al. 1999; Mintz et al., 2001). StentBoost (SB) enhancement allows an improved angiographic visualization of the stent (Koolen et al., 2005).

Relation of stent overexpansion to the angiographic no-reflow phenomenon in intravascular ultrasound-guided stent implantation for acute myocardial infarction

The angiographic no-reflow phenomenon is observed in some patients during stent implantation for acute myocardial infarction (AMI). We attempted to clarify the influence of stent overexpansion and plaque morphology on the angiographic no-reflow phenomenon in AMI patients who underwent intravascular ultrasound (IVUS)-guided stent implantation. We assessed the thrombolysis in myocardial infarction (TIMI) flow grade in the coronary angiographic findings, and quantitative and qualitative IVUS findings, in a total of 90 patients who underwent IVUS-guided stenting for AMI. The patients were divided into two groups according to the stent-to-artery ratio: overexpansion group (ratio 1.2) and non-overexpansion group (ratio <1.2). Angiographic no-reflow (defined as TIMI flow grade <3) in stent implantation was observed in 15 patients (17%). Angiographic no-reflow was more frequently observed in the overexpansion group than in the non-overexpansion group (32% vs 11%, P = 0.0312). Patients with no-reflow had more lipid pool-like images or fissure/dissection than those without. In the overexpansion group, a lipid pool-like image and fissure/dissection were more frequently observed in patients with no-reflow. The rate of target lesion revascularization (TLR) in the overexpansion group was significantly lower than that in the non-overexpansion group during the follow-up period (10% vs 18%, P = 0.0476), but the incidence of pump failure in the overexpansion group was higher than that in the non-overexpansion group during the hospital course (28% vs 14%, P = 0.0358). Stent overexpansion in AMI patients is related to a higher incidence of angiographic no-reflow, especially if the lesion has a lipid pool-like image or fissure/dissection, although there is a tendency for lower TLR.