Comparison of vascular response to the everolimus-eluting stent versus the paclitaxel-eluting stent: intravascular ultrasound results from the SPIRIT III trial

Effect of Hinge Motion on Stent Edge-Related Restenosis After Right Coronary Artery Treatment in the Current Drug-Eluting Stent Era

BACKGROUND

Stent edge-related restenosis (SER) remains a potential limitation of drug-eluting stent (DES). Hinge motion at the stent edge could lead to mechanical stress and contribute to incidents of SER. We investigated the effect of hinge motion on SER after implantation of current-generation DES in the right coronary artery (RCA), where excessive vessel movement is commonly observed.Methods and Results:Of 647 consecutive lesions in the RCA treated with second-generation or later DESs, 426 with follow-up angiography were included in this study. Intravascular imaging analysis was performed for 584 stent edges and reference segments. Binary restenosis occurred in 42 lesions (9.9%), and 55% were SERs. The hinge angle was significantly larger in the SER group than in the other restenosis or the no-restenosis group (17.9° vs. 11.6° and 10.6°, respectively; P<0.001). Lesions with an excessive hinge angle (>11.5°) had an increased rate of target lesion revascularization (19.1% vs. 7.2%; P<0.001) during the median follow-up period of 1,578 days. In per-edge analysis, hinge angle and residual plaque burden were independent predictors of SER. The coexistence of excessive hinge motion and residual plaque burden had a synergistic effect on stenotic progression in quantitative angiographic analysis (P_interaction<0.001) at follow-up angiography.

CONCLUSIONS

Substantial stress determined by angulation at a stent edge and its interaction with residual plaque can be considered as one plausible mechanism for SER.

Incidence of late-acquired stent malapposition of drug eluting stents with second generation permanent and biodegradable polymer coatings-A prospective, randomized comparison using optical coherence tomography

OBJECTIVES AND BACKGROUND

Polymer coatings of drug-eluting stents (DES) may induce allergic reactions and inflammation, resulting in late-acquired stent malapposition (LASM) with the risk of stent thrombosis. This study evaluated, if biodegradable polymer (BP) reduces the incidence of LASM compared to permanent polymer (PP) after treatment with newer generation DES.

METHODS AND RESULTS

Fifty patients with 59 lesions were randomized (2:1) to elective treatment with second generation PP-DES (n = 32, 39 stents), either Everolimus-eluting or Zotarolimus-eluting stents, or with BP-DES (Biolimus-eluting stents [BES]; n = 18, 20 stents) and underwent optical coherence tomography directly after implantation and after 1 year. After implantation acute stent malappositions (ASM) were documented in 30 stents (51%) distributed to 22 stents treated with PP-DES (56%) and 8 with BP-DES (40%; n.s.). After 1 year, late stent malappositions (LSM) were detected in 14 stents (24 %); ASM persisted (APSM) in 9 stents after one year (7 PP-DES-18%, 2 BES-10%), whereas ASM resolved in 21 stents. In addition, LASM was documented in nine stents including five stents without and four stents with additional APSM. All LASM were located in PP-DES (n = 9; 23%), none in BP-DES (P = 0.022). Compared to the reference lumen area, in-stent lumen area of stents without LASM was smaller due to neointimal hyperplasia (P = 0.021), whereas in-stent lumen area at maximum LASM of stents with LASM was larger due to positive remodeling (P = 0.002).

CONCLUSIONS

In conclusion the use of BP-DES reduced the occurrence of LASM due to positive remodeling compared to second generation PP-DES.

Late-acquired incomplete stent apposition after everolimus-eluting stent versus sirolimus-eluting stent implantation in patients with non-ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction

AIMS

Our aim was to evaluate the incidence and clinical outcomes of late-acquired incomplete stent apposition (LAISA) after implantation of first- and second-generation drug-eluting stents in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

Late-Acquired incomplete stent aPPOsition after everolimus-eluting stent versus sirolimus-eluting Stent ImplanTatION in pAtients with non ST-segment elevation Myocardial Infarction and ST-segment elevation myocardial infarction (APPOSITION-AMI) was a prospective, randomised study comparing LAISA after everolimus-eluting stent (EES) and sirolimus-eluting stent (SES) implantation in AMI patients. Intravascular ultrasound examination was serially performed post-procedurally and at eight-month follow-up in 195 AMI patients (205 native coronary lesions: 100 EES; 105 SES). LAISA was observed in 6.0% and 16.2% of EES- vs. SES-treated lesions (p=0.021), respectively. In 64.7% of SES-treated lesions, LAISA was caused by positive remodelling, whereas thrombus dissolution or plaque reduction was observed in 66.7% of EES-treated lesions. Among patients with LAISA, MACE developed in one (4.5%) in the SES group with no ST in either group up to one year.

CONCLUSIONS

The incidence of LAISA was lower in AMI patients treated with EES as compared to SES, mainly secondary to positive remodelling in SES- but not EES-treated lesions. Patients with LAISA in both groups showed a very low MACE incidence at one-year follow-up.

Randomized comparison of acute stent malapposition between platinum-chromium versus cobalt-chromium everolimus-eluting stents

No randomized data exist regarding optical coherence tomography (OCT) evaluation immediately post-procedure and at the 3-month follow-up for platinum-chromium everolimus-eluting stents (PtCr-EES) versus cobalt-chromium everolimus-eluting stents (CoCr-EES). A total of 100 patients were randomly assigned to undergo PtCr-EES (n = 51) or CoCr-EES (n = 49) implantation. OCT was serially evaluated after stent deployment with nominal pressure and immediately post-procedure, and 3-month follow-up. The primary endpoint was the percentage of malapposed strut after nominal pressure and immediately post-procedure. Compared to the CoCr-EES, the PtCr-EES showed a lower tendency of percent malapposed strut at nominal pressure [median value (interquartile range); 4.1 % (0.5-11.7) vs. 7.6 % (2.9-13.7), p = 0.082] and immediately post-procedure [1.2 % (0-3.4) vs. 2.5 % (0.7-5.3), p = 0.051]. The percentage of cross sections with any malapposed struts was significantly lower with PtCr-EES at nominal pressure [15.0 % (5.6-39.0) vs. 23.8 % (18.2-44.4), p = 0.036] and immediately post-procedure [6.5 % (0-15.3) vs. 10.5 % (7.1-20.0), p = 0.026]. At the 3-month follow-up, both PtCr-EES and CoCr-EES showed comparable percentages of malapposed struts (0 vs. 0 %, respectively, p = 0.332) and uncovered struts (5.3 vs. 4.7 %, respectively, p = 0.829). We found a significant correlation between the immediate post-procedural percentage of malapposed struts versus the percentage of uncovered struts (r = 0.430, p < 0.001) at the 3-month follow-up. Compared to the CoCr-EES, the PtCr-EES shows a lower tendency toward a lower percentage of malapposed struts but no significant difference in strut coverage at the 3-month follow-up. The percentage of malapposed struts immediately post-procedure was correlated with strut coverage at the 3-month follow-up.

Clinical validation of a novel software for quantitative analysis of coronary intravascular ultrasound

PURPOSE

CAAS IntraVascular (CAAS-IV) is a recently released software that provides options for sophisticated quantitative coronary ultrasound (QCU) analysis. The aim of this study was to validate CAAS-IV for QCU in diseased human coronaries.

METHODS

Ten preprocedural and 5 postprocedural IVUS studies were derived from daily practice. Intraobserver, interobserver, intersoftware (CAAS-IV vs. Curad) and interplatform (CAAS-IV vs. Volcano console) variability were assessed for cross-sectional area (CSA) measurements. Interobserver and intersoftware comparisons were made for volume measurements.

RESULTS

Measurements of lumen, EEM, plaque and stent CSA demonstrated small differences in the intraobserver (0.0±3.7%, -0.7±2.8%, -0.5±7.0% and -0.9±3.4%), interobserver (0.1±4.4%, 0.1±3.4%, -0.5±8.2% and -0.8±4.3%), intersoftware (-0.3±4.5%, 0.2±2.4%, 0.4±6.8% and -0.5±3.2%) and interplatform (0.7±7.9%, 0.9±4.0%, -1.1±12%, -1.8±3.6%) comparisons. For lumen, EEM, plaque and stent volume, the interobserver (-2.1±9.3%, 0.9±5.6%, 3.4±7.2% and -0.2±3.6%) and intersoftware (-2.2±6.2%, -2.6±6.1%, -2.7±12% and -4.1±3.2%) differences were substantially larger. Excluding large side-branches and calcifications, post-hoc measurements of lumen, EEM, plaque and stent volume showed small differences in the interobserver (-0.3±3.2%, 0.9±2.4%, 2.9±4.4% and -1.3±1.8%) and intersoftware (0.5±2.5%, -1.2±1.7%, -3.4±5.1% and -1.5±2.2%) comparisons. Analysis time for entire pullbacks was reduced by 19.2 [14.9-30.0]% using CAAS-IV (p<0.01).

CONCLUSIONS

CAAS-IV demonstrated reliable QCU with excellent agreement with previously validated software and the IVUS imaging console. Precision and reproducibility of measurements were high, proving CAAS-IV to be a valid option for QCU analysis in clinical practice and research. Interactive contour editing reduced analysis time by 20%.

Reproducibility of grayscale and radiofrequency IVUS data acquisition in stented coronary arteries

OBJECTIVES

Variability in data acquisition from intervened coronary arteries could represent a source of error that has implications for the design of serial stent studies. We assessed inter-pullback reproducibility of volumetric grayscale and radiofrequency intravascular ultrasound (IVUS) data in stented coronary arteries.

DESIGN

Fifteen patients with coronary artery lesions treated with stent implantation were included and examined with two separate pullbacks using the Eagle Eye Gold-phased array 20 MHz IVUS catheter (Volcano). The arteries were divided into five segments, giving a total of 150 sub-segments for analyses. Matching of frames was performed using landmarks that were clearly visible in coronary angiography and intravascular pullbacks. Data were analyzed off-line at an independent Corelab.

RESULTS

The inter-pullback reproducibility of geometrical data was very good for non-stented segments with relative differences less than 5% between pullbacks for lumen-, vessel-, and plaque volumes. For stented segments reproducibility was poorer with relative differences between pullbacks in the range of 5-10%. The inter-pullback reproducibility of compositional data demonstrated large standard deviations of relative differences, indicating a weaker agreement.

CONCLUSIONS

Agreements between pullbacks were weaker in stented than those in non-stented segments. Based on our data, future longitudinal IVUS studies in intervened vessels should account for a variability of 5-10% attributed to the acquisition of images.

Histopathological Comparison among Biolimus, Zotarolimus and Everolimus-Eluting Stents in Porcine Coronary Restenosis Model

Background and Objectives

The aim of this study was to examine the histolopathogical effects among the biolimus, zotarolimus, and everolimus eluting stent (EES) in the porcine coronary restenosis model.

Subjects and Methods

Pigs were randomized into three groups in which the coronary arteries (15 pigs, 10 coronaries in each group) had either a biolimus A9 eluting stent (BES, n=10), zotarolimus eluting stent (ZES, n=10) or an EES (n=10). Histopathologic analysis was performed at 28 days after stenting.

Results

There were no significant differences in the injury score among the three groups. There was a significant difference in the internal elastic lamina, lumen area, neointima area, percent area stenosis, and the fibrin and inflammation score among the three groups (4.3±0.53 mm², 2.5±0.93 mm², 1.8±1.03 mm², 40.7±20.80%, 1.7±0.41, 1.4±0.72 in the BES group vs. 5.1±0.55 mm², 2.3±1.14 mm², 2.8±1.00 mm², 55.4±21.23%, 2.0±0.39, 1.6±0.76 in the ZES group vs. 4.4±0.53 mm², 1.7±1.22 mm², 2.8±1.23 mm², 64.0±26.00%, 1.8±0.76, 2.1±0.90 in the EES group, respectively). BES is more effective in inhibiting neointimal hyperplasia compared to ZES and EES (p<0.0001). According to the fibrin and inflammation score, BES and EES are more effective in decreasing the fibrin deposition compared to ZES (p<0.001). Moreover, BES and ZES are more effective in reducing the inflammatory reaction compared to EES (p<0.001).

Conclusion

The result demonstrates that BES shows better histopathological characteristics than ZES and EES at one month after stenting in the porcine coronary restenosis model.