RETRACTION: Biological effect of microengineered grooved stents on strut healing: a randomised OCT-based comparative study in humans

This article¹ is retracted by the journal.

What happened after publication

The journal was alerted to issues in this content regarding the design, conduct or reporting of the work. These include:

• A discrepancy in the number of participants following a problem with randomisation: The authors agree that the numbers in the registry and paper are mismatched; seven participants are missing from the paper. They attribute this to an initial problem with randomisation. The first seven patients were excluded from the paper.

• Confusion about the type of stents used in the control arm: The authors say that the paper is correct and that the stents are made by Abbott, and that the registry is inaccurate.

• An additional 3 week outcome appears in the paper, but not in the study registry. The authors say this was planned, but did not appear in the registry in error.

• The death of one participant outside of the follow-up period. The authors say this was reported to the IRB board but not reported in the paper or included in the registry.

• Retrospective trial registration: The authors clarified that this was an administrative error on their part.

There are additional concerns regarding

• Possible undisclosed financial competing interests between Juan Granada and the study’s funder,² Palmaz Scientific. Granada has told the journal that he was unaware that Palmaz Scientific allegedly awarded him restrictive stock in 2013, and did not receive this stock before the company was dissolved in 2016.

• Ambiguity about the funder's role in the work. The authors told the journal that Palmaz Scientific and Abbott Vascular Systems provided funding for the study and approved the protocol design. They said that the collection, auditing, safekeeping, sorting, interpretation and analysis of the data was not completed by the funder, and that Palmaz Scientific and Abbott Vascular Systems had no input in the writing of the paper. However, two authors are employed by the funder, Palmaz Scientific, or by the provider of the stents, Abbott Vascular Systems.

Some of these issues were discussed with the authors and rapid responses were posted in 2018.² Further correspondence took place between 2024–2025. The authors have not responded adequately and after being notified of the journal’s continuing concerns on 30 October 2025, became unresponsive.

Reasons for retraction

This article is retracted because the authors have not adequately responded to concerns which could impact the reliability and integrity of the work.

Further action

The journal could not identify an organisation that could investigate the work.