Rationale and design of the East-West late lumen loss study: Comparison of late lumen loss between Eastern and Western drug-eluting stent study cohorts

Inter- and intra-core laboratory variability in the quantitative coronary angiography analysis for drug-eluting stent treatment and follow up

AIM

To evaluate inter-core laboratory variability of quantitative coronary angiography (QCA) parameters in comparison with intra-core laboratory variability in a randomized controlled trial evaluating drug-eluting stents.

METHODS

A total of 50 patients with 62 coronary lesions were analyzed by four analysis experts belonging to an Angiographic Core Laboratory (ACL: 1 expert) and a Cardiovascular Imaging Core Laboratory (CICL: 3 experts). QCA was based on the same standard operating procedure, but selections of projection and cine frames were at the discretion of each analyst. Inter- and intra-core laboratory variabilities were evaluated by accuracy, precision, Bland Altman analysis, and coefficient of variation.

RESULTS

Pre-MLD (minimal lumen diameter) was significantly smaller in results from ACL than those from all CICL experts. Number of analyzed projections did not affect pre-MLD results. Acute gain was larger in ACL than in CICL2. No significant difference was observed in late loss and loss index between inter-core laboratories. Agreement between core labs in the Bland-Altman analysis for each QCA parameter was as follows (mean difference, 95% limits of agreement): pre-MLD (-0.32, -0.74 to 0.10), stent MLD (0.08, -0.28 to 0.44), acute gain (0.22, -0.44 to 0.88), and late loss (-0.07, -0.69 to 0.55). Agreement between analysts in CICL (mean difference, 95% limits of agreement) was: pre MLD (-0.03, -0.37 to 0.31), stent MLD (0.15, -0.15 to 0.45), acute gain (0.05, -0.45 to 0.55), and late loss (0.04, -0.52 to 0.60). The widest limits of agreement among three analyses were shown in both analyses. Width of limited agreement in the intra-core laboratory analysis tended to be smaller than the inter-core laboratory analysis with these parameters. Coefficient of variation tended to be larger in lesion length (LL), acute gain, late loss, and loss index in inter- and in intra- core laboratory comparisons.

CONCLUSION

Inter-core laboratory QCA variability in late loss and loss index analysis could be similar to intra-core laboratory variability, but more strict alignment between core laboratories would be necessary for initial procedural data analysis.

The East-West late lumen loss study: Comparison of angiographic late lumen loss between Eastern and Western drug-eluting stent study cohorts

BACKGROUND

Regulatory decisions approving new coronary drug-eluting stent (DES) require mechanistic observations of angiographic late lumen loss (LLL). Patient safety and device approval times could be enhanced if angiographic follow-up data were found to be generalizable across jurisdictions and geographies. The objectives were to assess the comparability of in-segment LLL in Eastern and Western DES populations using the world's largest compilation of follow-up quantitative coronary angiography data.

METHODS

Data from 4 manufacturers involving 29 DES clinical trials in Eastern and Western hemispheres were compiled. "East" and "West" cohorts were defined by trial location. Independent core laboratories quantified in-segment LLL for all studies. East and West were compared before and after adjustment for clinical and anatomic covariates known to correlate with LLL via conditioning on propensity score quintiles. An international panel of experts and regulators prospectively established a clinically meaningful difference between East and West mean in-segment LLL of ±0.40 mm.

RESULTS

The data set comprised 2,047 East and 4,456 West patients. Unadjusted mean ± SD for West and East in-segment LLL (mm) was 0.25 ± 0.46 and 0.12 ± 0.42, respectively (difference 0.13 mm; 95% CI 0.11-0.16). Propensity score-adjusted in-segment LLL East and West least squares means were 0.11 and 0.26 mm, respectively (difference 0.15 mm; 95% CI 0.13-0.18).

CONCLUSIONS

In the world's largest compilation of DES protocol 8- to 13-month angiographic follow-up data, clinically meaningful comparability of in-segment LLL by independent core laboratory quantitative coronary angiography in East and West cohorts was demonstrated in both unadjusted and adjusted comparisons. These findings suggest that DES LLL, once characterized, could be generalized across regulatory jurisdictions over the course of global registration efforts.

Methods to assess bioresorbable vascular scaffold devices behaviour after implantation

Bioresorbable vascular scaffolds (BRS) represent a novel approach for coronary revascularization offering several advantages as compared to current generation DES, potentially reducing rate of late adverse events and avoiding permanent vessel caging. Nevertheless, safety concerns have been raised for an increased risk of scaffold thrombosis (ScT) in both early and late phases, probably related to a suboptimal scaffold implantation. In this context, the use of different imaging methodologies has been strongly suggested in order to guarantee an optimal implantation. We herein analyze the different imaging methodologies available to assess BRS after implantation and at follow-up.