Two-year follow-up intravascular ultrasound analysis after bare metal stent implantation in 120 lesions.

The objective of this study was to examine long-term changes after bare metal stent implantation in a relatively large number of patients. There are few reports of intravascular ultrasound (IVUS) studies performed on stented and nonstented (reference) segments beyond 6 months after bare metal stenting. Using IVUS, we evaluated serial changes in stented and reference segments between 6 and 24 months after stent implantation in 110 patients with 120 lesions. Serial IVUS images were acquired at five equidistant intrastent sites and at two different reference segment sites. Measurements were made of the external elastic membrane (EEM), stent, lumen, and intimal hyperplasia (IH = stent - lumen) area. For the whole patient group, between 6 and 24 months, the mean IH area in stented segments decreased from 2.6 +/- 1.0 to 2.3 36+/- 0.9 mm2 (P < 0.001), and the mean lumen area increased from 6.2 +/- 2.0 to 6.5 +/- 1.9 mm2 (P < 0.001). The mean IH area decreased in 91 lesions (76%) and increased in 29 lesions (24%) between 6 and 24 months. There were no significant changes in EEM or lumen area in the reference segments. Late angiographic restenosis (diameter stenosis > or = 50%) occurred in three lesions between 6 and 24 months. A late target lesion revascularization was performed for one lesion. In the period of time between 6 and 24 months after stenting, IH regression occurred in most (76%) stent lesions, resulting in late lumen increase. However, IH progression was observed in 24% of in-stent lesions. No significant changes of EEM or lumen area occurred in the reference segments.     

Late incomplete stent apposition after sirolimus-eluting stent implantation: a serial intravascular ultrasound analysis.

OBJECTIVES: We sought to identify the frequency of incomplete stent apposition (ISA) in sirolimus-eluting stents (SES) and clarify its findings and clinical sequelae. BACKGROUND: Late-acquired ISA has been reported in bare-metal stents (BMS) and brachytherapy and recently in drug-eluting stents. However, the characteristics of late ISA in SES have not been clarified. METHODS: From the SIRIUS trial, a randomized, multicenter study comparing SES and BMS, serial qualitative intravascular ultrasound (IVUS; at stent implantation and eight-month follow-up) was available in 141 patients (BMS: n = 61; SES: n = 80). The IVUS images were reviewed for the presence of ISA. RESULTS: Incomplete stent apposition at follow-up was observed in 19 patients (BMS: n = 6 [9.8%]; SES: n = 13 [16.3%]; p = NS). Among these, 12 had ISA after intervention and at follow-up (persistent ISA). Late-acquired ISA was seen in the remaining seven cases, all from the SES group (BMS: n = 0; SES: n = 7 [8.7%]; p < 0.05). In late-acquired ISA, there was an increase in external elastic membrane area (after intervention: 16.2 +/- 2.7 m2; follow-up: 18.9 +/- 3.6 mm2; p < 0.05). The location of stent-vessel wall separation was primarily at the stent edges in persistent ISA cases, whereas late-acquired ISA in SES occurred mostly in the mid portion of the stent. There were no negative clinical events reported for any ISA cases at 12-month clinical follow-up. CONCLUSIONS: Late ISA was observed in 8.7% of patients after SES implantation. There were no negative clinical events associated with this IVUS finding at 12-month clinical follow-up; however, careful long-term follow-up will be necessary.     

Two-year serial coronary angiographic and intravascular ultrasound analysis of in-stent angiographic late lumen loss and ultrasonic neointimal volume from the TAXUS II trial

Late loss has been used as a reliable surrogate end point for evaluation and differentiation of short-term performance of drug-eluting stents. This study investigated the consistency between angiographic and intravascular ultrasound (IVUS) outcomes of late lumen loss (late loss) and neointimal growth to measure restenotic plaque load in TAXUS and bare metal stents. The randomized TAXUS II trial evaluates the polymer-based paclitaxel-eluting TAXUS stent in slow- and moderate-release formulations. Serial angiographic and IVUS analyses were available in 155 event-free patients (bare metal stent, 74; TAXUS stent, 81) after the procedure, at 6 months, and at 2 years. For this subanalysis, quantitative coronary angiographic (QCA) and IVUS measurements were used to derive late loss and neointimal volume. From after the procedure to 6 months, quantitative coronary angiography and IVUS showed matching results for the 2 groups with significant decreases in late loss and neointimal volume in the TAXUS versus the control group. From 6 months to 2 years, QCA and IVUS measurements also showed results similar to those in the control group, demonstrating neointimal compaction over time. However, in the TAXUS group, QCA late loss showed a nonsignificant decrease from 6 months to 2 years, whereas IVUS neointimal volume increased. In conclusion, although QCA and IVUS results were similar over the first 6 months, long-term assessment of changes in restenotic plaque load showed discrepant findings for the TAXUS. These findings suggest the need for critical reevaluation of current end points and the use of more precise techniques to detect lumen and stent boundaries.     

Late catch-up phenomenon associated with stent fracture after sirolimus-eluting stent implantation: incidence and outcome

Objective: To examine the long‐term outcome of the stent fracture (SF) and the potential predictive factors contributing to in‐stent restenosis (ISR) in the fractured stent. Background: The SF is thought to be a higher risk of ISR in drug‐eluting stent, although SF does not always develop ISR. Methods: The consecutive 1,228 de novo lesions in 1,079 patients who underwent sirolimus‐eluting stents implantation and assessed by 8 months follow‐up coronary angiography were retrospectively analyzed. Results: One hundred and seventeen SFs (9.5%) were identified in 100 patients and 22 (18.8%) SFs revealed ISR at the first follow‐up. In addition, 16 (13.7%) developed new ISRs from 95 residual SFs without ISR prior to the second follow‐up. Overall, 38 (32.5%) of all 117 SFs developed ISR, and 16 (42.1%) of 38 SFs occurred in a late phase beyond the first 8 months follow‐up. A higher risk of ISR in the SF site was associated with the chronic total occlusion (ISR vs. no ISR: 34.2% vs. 16.5%, P = 0.0304), calcified lesions (55.3% vs. 34.2%, P = 0.0299), and correspondence 89.5% versus 43.0%, P < 0.0001 (SF site occurring at the original target lesion site) in the univariate analysis. The correspondence was identified as the only strong predictive factor for ISR at the SF site according to a multivariate logistic regression analysis (odds ratio 12.6, 95% confidence interval 3.82–53.5, P < 0.0001). Conclusions: SF occurring at the site of the original target lesion was a strong independent predictor of ISR. This indicates the need for a careful, long‐term follow‐up in those situations, even when no significant ISR is initially detected. (J Interven Cardiol 2011;24:165–171)     

Angiographic and intravascular ultrasound findings of the late catch-up phenomenon after intracoronary beta-radiation for the treatment of in-stent restenosis

We report one-year angiographic and intravascular ultrasound (IVUS) outcomes of in-stent restenosis (ISR) patients treated with intravascular brachytherapy (IVBT). The benefit of IVBT for treating ISR is well documented. However, few data exist on significant angiographic and intravascular ultrasonic in-stent lumen deterioration beyond the habitual 6-month analysis after the index radiation procedure or so-called late catch-up process in the treatment of ISR. Twenty-five consecutive patients with ISR were treated with IVBT using the Beta-Cath System (a 40 mm 90 Sr per 90 gamma source). Quantitative angiographic and IVUS analysis was performed in all of them at 6 and 12 months. IVBT was successful in all patients. Four patients (16%) developed recurrent angiographic binary restenosis at 6-month follow-up, all located within the adjacent reference segments, with 2 being associated with geographical miss. An additional 4 patients (16%) presented with recurrent ISR at 12-month follow-up, all within the stented segment. Significant in-stent lumen loss (0.16 +/- 0.42 mm to 0.34 +/- 0.46 mm; p = 0.008) and in-stent intimal hyperplasia growth (+11.2 +/- 0.48 mm3; p = 0.03) was observed between 6 and 12 months. Intracoronary beta-radiation for the treatment of ISR was associated with significant luminal deterioration (late catch-up) within the stents between 6 and 12 months due to an important late progression of in-stent intimal hyperplasia.     

Intravascular ultrasound predictors of angiographic restenosis after sirolimus-eluting stent implantation.

AIMS: In many countries, drug-eluting stent implantation is the dominant interventional strategy. We evaluated the clinical, angiographic, procedural, and intravascular ultrasound (IVUS) predictors of angiographic restenosis after sirolimus-eluting stent (SES) implantation. METHODS AND RESULTS: SES implantation was successfully performed in 550 patients with 670 native coronary lesions. Six-month follow-up angiography was performed in 449 patients (81.6%) with 543 lesions (81.1%). Clinical, angiographic, procedural, and IVUS predictors of restenosis were determined. Using multivariable logistic regression analysis, the only independent predictors of angiographic restenosis were post-procedural final minimum stent area by IVUS [odds ratio (OR)=0.586, 95% confidence interval (CI) 0.387-0.888, P=0.012] and IVUS-measured stent length (OR=1.029, 95% CI 1.002-1.056, P=0.035). Final minimum stent area by IVUS and IVUS-measured stent length that best separated restenosis from non-restenosis were 5.5 mm2 and 40 mm, respectively. Lesions with final minimum stent area<5.5 mm2 and stent length>40 mm had the highest rate of angiographic restenosis [17.7% (11/62)], P<0.001 compared with other groups. CONCLUSION: Independent predictors of angiographic restenosis after SES implantation were post-procedural final minimum stent area by IVUS and IVUS-measured stent length. The angiographic restenosis rate was highest in lesions with stent area<5.5 mm2 and stent length>40 mm.     

Intravascular ultrasound characterization of the "black hole" phenomenon after drug-eluting stent implantation

An intraluminal echolucent tissue, dubbed "black hole," has been identified by intravascular ultrasonography after intracoronary brachytherapy. This study reports the characteristics and incidence of the black hole in patients treated with drug-eluting stent implantation using a sirolimus-eluting stent (SES). We included intravascular ultrasound data from the Compassionate Use of Sirolimus-Eluting Stent (SECURE, n = 61 lesions) registry, a study involving patients in whom previous brachytherapy had failed, and the DIABETES trial (n = 165 lesions), a multicenter, randomized study comparing SES versus bare metal stents in diabetic patients. Intravascular ultrasound follow-up was scheduled at 8 months (SECURE trial, post-brachytherapy population) and 9 months (DIABETES trial). In the SECURE population, a black hole was observed in 10 patients (19.6%). Seven black hole segments had significant intimal hyperplasia (> 10%). A black hole accounted for 27% of total intraluminal tissue. In the DIABETES trial, 2 patients (2.5%) in the SES group and none in the bare metal stent group showed echolucent intimal hyperplasia. In conclusion, a black hole occurred frequently after implantation of a SES in patients in whom intracoronary brachytherapy had previously failed. Black holes were also identified in a nonirradiated population, although the incidence was lower than in the post-brachytherapy patients. Bare metal stents were not associated with this phenomenon.     

Simultaneous two-vessel very late stent thrombosis and coronary aneurysm formation after sirolimus-eluting stent implantation: an intravascular ultrasound evaluation

Very late stent thrombosis is a rare but devastating complication. Several factors are known to contribute to its occurrence, and are related to the patient, procedure, lesion and premature discontinuation of antiplatelet therapy. This report describes the case of a 49-year-old patient with simultaneous two-vessel stent thrombosis (left anterior descending and circumflex arteries) 24 months after sirolimus-eluting stent implantation. The importance of intravascular ultrasound is enhanced. The potential contributing factors to the stent thrombosis are analyzed.     

Comparison of quantitative angiographic parameters with the magnitude of neointimal hyperplasia measured by volumetric intravascular ultrasound in patients treated with bare metal and nonpolymeric paclitaxel-coated stents

We used data from the ASian Paclitaxel-Eluting Stent Clinical Trial (a 3-center, randomized, placebo-controlled trial of nonpolymeric paclitaxel-coated stents with a single-center intravascular ultrasound substudy) to compare angiographic indexes of drug-eluting stent efficacy with the magnitude of intimal hyperplasia (IH) assessed by intravascular ultrasound. Overall, percent IH (IH volume divided by stent volume) was larger in restenotic lesions than in nonrestenotic lesions (46 +/- 19% vs 15 +/- 13%, p <0.0001); angiographic late loss and follow-up diameter stenoses correlated strongly with percent IH.     

Clinical and angiographic follow-up after single long GFX coronary stent implantation.

In order to identify predictors of late restenosis after GFX stent implantation, procedural and 6-month clinical and angiographic follow-up data of prospectively entered 141 consecutive lesions treated with a single long (24 or 30 mm) GFX stent were compared to 66 consecutive lesions requiring a single short (12 or 18 mm) stent. The initial clinical success rate of 97% and thrombosis rate of 1.4% with long stents were similar to 97% and 0% with short stents (P = NS). Their respective binary restenosis rates were 34.7% and 23.3% for long and short stents as a whole (P = NS), but being 10.0% for 12 mm, 26.0% for 18 mm, 31.3% for 24 mm, and 39.2% for 30 mm. When proximal and distal reference diameters at baseline were compared between the lesions with and without restenosis, proximal reference diameters were not statistically different (3.02+/-0.42 mm vs. 3.18+/-0.62 mm) and the restenosis group had significantly smaller distal reference diameters (2.15+/-0.48 mm vs. 2.55+/-0.53 mm, P<0.0001). The treatment of long lesions with single long-stent implantation can be accomplished with high success and low complication rates. Single long-stent implantation may be effective, if the distal reference size of the long narrowing is big enough to accept the stent.     

Relationship between fractional flow reserve and residual plaque volume and clinical outcomes after optimal drug-eluting stent implantation: Insight from intravascular ultrasound volumetric analysis

Background

The underlying cause of FFR reduction and prognostic impact of FFR after optimal DES implantation remain unknown. The study aims were to use intravascular ultrasound (IVUS) to investigate the mechanism responsible for reduced fractional flow reserve (FFR) after optimal drug-eluting stent (DES) implantation and to evaluate FFR effect on clinical outcomes after optimal percutaneous coronary intervention with DES.

Methods

Ninety-seven patients treated with optimal DES implantation under IVUS and pullback FFR guidance were followed clinically (median 17.8 months). Post-stenting IVUS examination and pullback FFR recording were performed, and angiographic and IVUS parameters associated with reduced FFR were evaluated. The composite of major adverse cardiac events (MACE), including cardiac death, myocardial infarction, stent thrombosis, and target vessel revascularization, was analyzed.

Results

Regression analysis showed inverse correlations between post-stent FFR and residual plaque volume index (r = − 0.40, p < 0.01) and residual percent plaque volume (r = − 0.68, p < 0.01) in IVUS but no correlation of minimal lesion diameter with quantitative coronary angiography (r = 0.07, p = 0.50) or IVUS-derived minimal stent area (r = 0.02, p = 0.84). MACE was observed in 10 patients (10.3%), and FFR after optimal stenting was significantly lower in this group (0.86 ± 0.04 vs 0.91 ± 0.04, p < 0.01). The optimal FFR threshold for predicting MACE was 0.90, identified by the receiver operating characteristic curve.

Conclusions

Reduced FFR after optimal DES implantation was associated with residual plaque volume identified by IVUS and future adverse cardiac events.     

Characterization of plaque prolapse after drug-eluting stent implantation in diabetic patients: a three-dimensional volumetric intravascular ultrasound outcome study.

OBJECTIVES: The aim of this research was to evaluate the plaque prolapse (PP) phenomenon after bare-metal (BMS) and drug-eluting stent (DES) implantation in patients with diabetes mellitus using 3-dimensional volumetric intravascular ultrasound (IVUS). BACKGROUND: Plaque prolapse has been observed in up to 22% of patients treated with BMS. Diabetic patients have a larger atherothrombotic burden and may be more prone to have PP. However, the incidence of PP and its clinical impact after DES implantation is unknown. METHODS: Three-dimensional IVUS was performed after intervention and at 9-month follow-up in 168 patients with diabetes (205 lesions) treated with bare BX Velocity stents ((BX Velocity/Sonic, Cordis, Johnson & Johnson) (BMS, n = 65), sirolimus-eluting stents (Cypher, Cordis) (SES, n = 69), and paclitaxel-eluting stents (Taxus, Boston Scientific, Natick, Massachusetts) (PES, n = 71). Intravascular ultrasound data at the sites of PP were compared with stented segments without PP in each lesion. Outcomes were evaluated at 9- and 12-month follow-up. RESULTS: There were 42 sites of PP (BMS = 11, SES = 11, PES = 20, p = NS) in 34 stented segments of 205 (16.6%) lesions. Plaque prolapse was more frequent in the right coronary artery and in chronic total occlusion lesions. Post-procedure PP volume was 1.95 mm3 in BMS, 2.96 mm3 in SES, and 4.53 mm3 in PES. At follow-up, tissue volume increased at PP sites in both BMS and PES, but not after SES. Neointimal proliferation was similar between PP and non-PP sites. Stent thrombosis and restenosis rates were similar between PP and non-PP lesions. CONCLUSIONS: The incidence of PP after implantation of new generation tubular stents in patients with diabetes remains high. Drug-eluting stent implantation was not associated with increased risk of PP. Plaque prolapse was not associated with stent thrombosis or increased neointimal proliferation.     

Significance of angiographic haziness at the distal stent edge: analysis by intravascular ultrasound and quantitative coronary angiography]

Haziness on coronary angiograms has been interpreted as thrombogenic morphologies such as dissection or thrombus. Haziness is often seen at distal sites following stent deployment. To clarify the pathophysiology of distal haziness of coronary stenting, we performed intravascular ultrasonography (3.5F, 30 MHz) after implantation of 48 Palmaz-Schatz stents in 45 patients. Haziness was defined visually as a reduction in contrast density or an indistinct vessel border. The luminal diameter and videodensitometry score were measured at the distal edge of the stent and distal adjacent segment by quantitative coronary angiography. Luminal diameter and lumen area were measured by intravascular ultrasound. The distal/in-stent ratio was calculated for each measurement to assess the magnitude of the vessel tapering and the reduction in contrast density. Haziness was found in 18 vessels. Qualitative intravascular ultrasound determined dissections (n = 5) and irregular shapes of the lumen compressed by heavy calcium (n = 3) in the hazy vessels. There were no specific morphologies in the other 10 cases. Distal/in-stent ratio of the videodensitometry score was significantly smaller in hazy vessels, but quantitative coronary angiography could not distinguish hazy arteries with dissection or calcium from arteries without specific morphologies. The distal/in-stent ratio of the lumen area (< 0.8) and lumen area at the distal segment (< 5 mm2) were markedly smaller in the 'hazy' group without specific morphologies. Dissection, heavy calcium, and luminal reduction can cause a hazy appearance at the distal stent edge. Quantitative coronary angiography could quantify the haziness, but could not distinguish the morphologies of the vessel wall. Only intravascular ultrasound could assess the pathophysiology of hazy vessels after coronary stenting.