Drs. Andrew Sage, Shaf Keshavjee and Bo Wang
The study was led by, (L to R), Dr. Andrew Sage, lead author, and Drs. Shaf Keshavjee and Bo Wang, co-senior authors. (Photos: UHN StRIDe Team)​

A new study from researchers at Toronto General Hospital Research Institute (TGHRI) has identified a way to predict and guide transplant physicians on donor lung suitability and transplant outcomes using artificial intelligence (AI) and machine learning tools.

Ex vivo lung perfusion (EVLP) is a medical technique, invented at UHN, in which a donated lung is preserved outside of the body so that it can be assessed and treated prior to transplant. This process helps to ensure that the lung is healthy and functioning properly before being transplanted into a patient.

"Although EVLP has improved the number of transplant procedures conducted, this increase still falls significantly short of the growing number of individuals added to the transplant waiting list each year – a problem that has been compounded by the pandemic," says Dr. Shaf Keshavjee, Director of the Latner Thoracic Surgery Research Laboratories and Director of the Toronto Lung Transplant Program within UHN's Ajmera Transplant Centre and UHN's Sprott Department of Surgery.

"Additionally, the assessment of lungs undergoing EVLP is largely subjective," says Dr. Keshavjee, who is also a Senior Scientist at TGHRI, Chief of Innovation at UHN and a professor at the University of Toronto (U of T). "There are no standardized guidelines that can accurately determine which organs are suitable for transplant."

While AI and machine learning tools have begun to make an impact on clinical decision-making, the use of AI for organ transplantation has not yet been studied.

"We wanted to understand whether AI could aid clinicians in determining whether a donor lung was suitable for transplant," says Dr. Bo Wang, Chief AI Scientist at UHN and a scientist at TGHRI.

"To do this, we utilized a machine learning program called Extreme Gradient Boosting (XGBoost), which studies large sets of data to make predictions using an ensemble of decision trees – a series of questions that the model asks about the data," says Dr. Wang, who is also a Tier 2 Canada Research Chair in Artificial Intelligence for Medicine and assistant professor at U of T.

concept image of information flow
InsighTx uses data from EVLP and donors in order to make a decision on suitability for transplant. Data types include airway pressure, biomarkers of inflammation, donor body mass index and more. (Image created with BioRender.com)

"We analyzed data from 725 EVLP cases using InsighTx," says Dr. Andrew Sage, assistant scientist within the Toronto Lung Transplant Program, UHN's Ajmera Transplant Centre and TGHRI. "We showed that the InsighTx AI model learned from this EVLP data and was able to predict which lungs were unsuitable for transplant and which transplants would have good outcomes for patients."

Additionally, in a real-world evaluation of surgical decision-making​, lung suitability assessments made by a group of trained clinicians were compared with or without the aid of InsighTx. The results of this evaluation demonstrated that InsighTx increased the likelihood of getting it right – that is transplanting suitable donor lungs and not transplanting unsuitable donor lungs.

This study suggests that the impact of AI on transplantation rates could be dramatic and that an overall increase in safe organ utilization and transplant activity is plausible.

"This is the first evidence that an AI-guided approach could lead to a safe increase in the number of transplants performed following EVLP," says Dr. Sage, who is also an assistant professor at U of T. "As the need for viable organs continues to grow, this knowledge would be a significant step forward in the field of organ transplantation."

This work was supported by UHN's Ajmera Transplant Centre, the Canadian Institutes of Health Research and UHN Foundation.

Dr. Keshavjee serves as Chief Medical Officer of Traferox Technologies and receives personal fees from Lung Bioengineering, outside of this published work. Drs. Sage, Valero, Liu, Cypel, Wang and Keshavjee are inventors of patents related to this work.

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