In a 16-page report, Dr. Hamsten rejected the findings of an independent investigator whom the institute had hired. Bengt Gerdin, an emeritus professor at Uppsala University Hospital, had concluded that Dr. Macchiarini omitted or falsified information about the conditions of the three patients in the papers, including one published in December 2011 by the British journal The Lancet.

But Dr. Hamsten said that since the investigator’s report was released in May, Dr. Macchiarini and others had provided new information “that is critical to how the complaint is assessed.” Among other things, Dr. Hamsten wrote, newly submitted statements from doctors had given a clearer picture of how one patient, an Eritrean man living in Iceland whose case is the focus of the Lancet paper, was evaluated. He said it could be appropriate for Dr. Macchiarini to submit corrections for some of the published papers.

Dr. Hamsten said that Dr. Macchiarini had also obtained approvals for the operations from a local ethics committee, a subject that had been in dispute. But he said that other ethics accusations against the surgeon, regarding whether he had obtained other permits and clearances for the research, were not included in the decision, and that a prosecutor was conducting a preliminary inquiry on those issues.

In an interview, Dr. Hamsten said it was “regrettable” that all the information about the patients had not been available to the investigator. He said Dr. Macchiarini had not had all the patient information assembled in one place, as is called for by good clinical practice. “That’s why we have ruled that Macchiarini did not act with due care in certain areas of his work,” Dr. Hamsten said.

As a visiting professor at Karolinska, Dr. Macchiarini leads a laboratory that researches ways to create human tissues inside or outside the body. His work, one of many efforts around the world to make human tissues as an eventual way to fight diseases and ease transplant shortages, was the subject of a front-page article in The New York Times in 2012.