Comparison of definitions of coronary artery reference sizes and effects on stent selection and evaluation of stent expansion

Accurate determination of coronary reference size is essential for optimal stent selection and evaluation of stent expansion during percutaneous coronary intervention (PCI). Several approaches for reference size estimation have been published with no universal agreement. The aim of this study was to investigate if potential differences in coronary reference size estimation lead to differences in stent and balloon selection and in detection of stent under expansion. Definitions for coronary reference size estimation, stent size selection, and stent expansion were identified in 17 randomized controlled trials. The identified methods were applied in a population of 32 clinical cases. Reference size estimates ranged up to 1.35mm, and indicated nominal stent size ranged up to 1.0 mm in the same case depending on method. Mean relative stent expansion ranged from 54±12% to mean 100±29% depending on the applied reference method. Choice of method for reference size estimation using intravascular imaging may influence stent selection and greatly affects evaluation of post-PCI stent expansion.

Early healing after treatment of coronary lesions by thin strut everolimus, or thicker strut biolimus eluting bioabsorbable polymer stents: The SORT-OUT VIII OCT study

AIMS

Early healing after drug-eluting stent (DES) implantation may reduce the risk of stent thrombosis. The aim of this study was to compare patterns of early healing after implantation of the thin strut everolimus-eluting Synergy DES (Boston Scientific) or the biolimus-eluting Biomatix Neoflex DES (Biosensors).

METHODS AND RESULTS

A total of 160 patients with the chronic or acute coronary syndrome were randomized 1:1 to Synergy or Biomatrix DES. Optical coherence tomography (OCT) was performed at baseline and at either 1- or 3-month follow-up. The primary endpoint was a coronary stent healing index (CSHI), a weighted index of strut coverage, neointimal hyperplasia, malapposition, and extrastent lumen. A total of 133 cases had OCT follow-up and 119 qualified for matched OCT analysis. The median CSHI score did neither differ significantly between the groups at 1 month: Synergy 8.0 (interquartile range [IQR]: 3.0; 14.0) versus Biomatrix 8.5 (IQR: 4.0; 15.0) (p = 0.47) nor at 3 months: Synergy 6.5 (IQR: 2.0; 13.0) versus Biomatrix 6.0 (IQR: 4.0; 11.0) (p = 0.83). Strut coverage was 84.6% (IQR: 72.0; 97.9) for Synergy versus 77.6% (IQR: 70.1; 90.3) for Biomatrix (p = 0.15) at 1 month and 90.3% (IQR 79.0; 98.8) (Synergy) versus 83.9% (IQR: 77.5; 92.6) (Biomatrix) (p = 0.068) at 3 months. Pooled 1- and 3-month coverage was 88.6% (IQR: 74.4; 98.4) for Synergy compared with 80.7% (IQR: 73.2; 90.8) for Biomatrix (p = 0.02).

CONCLUSIONS

The early healing response after treatment with the Synergy or Biomatrix DES did not differ significantly as determined by a healing index. The Synergy DES showed overall better early stent strut coverage.

Five-Year Clinical Outcome of the Biodegradable Polymer Ultrathin Strut Sirolimus-Eluting Stent Compared to the Biodegradable Polymer Biolimus-Eluting Stent in Patients Treated With Percutaneous Coronary Intervention: From the SORT OUT VII Trial

BACKGROUND

Biodegradable polymer drug-eluting stents were developed to improve safety and efficacy outcomes for patients undergoing percutaneous coronary intervention. However, few long-term follow-up efficacy studies are available. The study sought to investigate 5-year results from the SORT OUT VII trial (Scandinavian Organization for Randomized Trials With Clinical Outcome) comparing the biodegradable polymer ultrathin-strut sirolimus-eluting Orsiro stent (O-SES) versus the biodegradable polymer biolimus-eluting Nobori stent (N-BES).

METHODS

This registry-based, randomized, multicenter, single-blinded, noninferiority trial compared O-SES and N-BES in an all-comer population. The composite primary end point, target lesion failure, consisted of cardiac death, myocardial infarction related to the target lesion, or target lesion revascularization within 1 year. Follow-up was extended to 5 years.

RESULTS

Five-year follow-up was completed for 2521 patients (99.8%). Five-year target lesion failure did not differ between O-SES (12.4%) and N-BES (13.1%; rate ratio [RR], 0.94 [95% CI, 0.75-1.18]). Cardiac death (RR, 0.95 [95% CI, 0.67-1.34]), target myocardial infarction (RR, 1.14 [95% CI, 0.76-1.71]), target lesion revascularization (RR, 0.90 [95% CI, 0.67-1.21]), and definite stent thrombosis rates (RR, 0.73 [95% CI, 0.41-1.33]) did not differ significantly between the 2 stents. Within the first year, definite ST was significantly lower for O-SES (0.4%) compared to N-BES (1.2%; RR, 0.33 [95% CI, 0.12-0.92]), but no difference was from 1 through 5 years: O-SES 1.2% and N-BES 0.9% (RR, 1.28 [95% CI, 0.58-2.82]).

CONCLUSIONS

Five years after treatment with biodegradable polymer stents, target lesion failure did not differ among O-SES and N-BES. Definite stent thrombosis was less often seen within the first year in the O-SES but the difference was not maintained after 5 years.

REGISTRATION

URL: https://clinicaltrials.gov; Unique identifier: NCT01879358.

Early vascular healing after implantation of the polymer-free biolimus-eluting stent or the ultrathin strut biodegradable polymer sirolimus-eluting stent in patients with ST-segment elevation myocardial infarction

OBJECTIVE

To evaluate the difference in early vascular healing between the ultrathin-strut biodegradable-polymer sirolimus-eluting Orsiro stent (O-SES) and the polymer-free biolimus-A9-eluting BioFreedom stent (BF-BES), assessed with optical coherence tomography (OCT) after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarctions (STEMIs).

METHODS

Eighty patients with STEMI who underwent primary PCI were randomly allocated 1:1 to treatment with BF-BES or O-SES. OCT was acquired after PCI and at 1-month follow-up. The primary endpoint was 1-month OCT-assessed vascular healing index based on the presence of uncovered and malapposed stent struts and intraluminal filling defects where low vascular healing index indicated favorable vascular healing.

RESULTS

At 1-month, the vascular healing index was similar in O-SES 11.5 [interquartile range (IQR) 9.5-17.5], compared to BF-BES 11.5 (IQR 7.1-12.5; P = 0.14). Percentage of uncovered struts [O-SES 31.5% (IQR 20.7-41.9), P = 0.43] vs. BF-BES 27.8% (IQR 19.4-41.9; P = 0.44), and median volume of neointimal hyperplasia [O-SES 4.9 mm3 (IQR 1.4-13.1) vs. BF-BES 7.1 mm3 (IQR 2.8-17.0), P = 0.18] did not differ significantly between the two stent groups. Complete coverage was not observed in any of the stents. The percentages of stents with malapposition did not differ significantly (O-SES 87.1% vs. BF-BES 71.4%, P = 0.14) whereas percentage of malapposed struts [O-SES 3.5% (IQR 0.8-5.5) vs. BF-BES 0.8% (IQR 0.0-1.8), P = 0.003] was lower in the BF-BES group.

CONCLUSION

In patients with STEMI, the drug-coated BF-BES and the thin strut O-SES had similar vascular healing index at 1-month. However, the thin O-SES struts were more often malapposed.