Extracorporeal membrane oxygen support appears to be beneficial in patients with advanced interstitial lung disease (ILD), according to a new meta-analysis. Specifically, , although the confidence in the finding was low.
ECMO has been used increasingly in ILD patients over the past 10-15 years for acute decompensation as well as a bridge to lung transplant, according to Prasanth Balasubramanian, MD, but clinical evidence for its use is limited to case series or short-term retrospective studies. “We don’t have robust evidence on whether it really helps with the outcome, and which mode is better, so that’s why we decided to do a study on this,” said Dr. Balasubramanian, who is a fellow in pulmonary critical care at Mayo Clinic (Jacksonville, Fla.). He presented the new research at the annual meeting of the American College of Chest Physicians (CHEST).
The results were encouraging, according to the study’s lead author Pramod Guru, MD. “I think what we take from this analysis is that ECMO should not be considered as a contraindication for people you are considering for lung transplant. If we have this population of people who are very sick, but we have the opportunity to solve them with VA ECMO and then give the transplantation possibly, that may be the way,” said Dr. Guru, who is a critical care specialist at Mayo Clinic, Jacksonville, Fla. He acknowledged that more work needs to be done to determine whether VA or VV is best in specific patient populations.
The meta-analysis included 18 studies with a total of 1,341 patients, who were a mean age of 55.89 years and 61.08% of whom were male. Most procedures (75.3%) were VV. The overall mortality was 52.6%, including 59.7% for VV ECMO and 34.2% for VA ECMO. The survival difference did not reach statistical significance (odds ratio, 0.48; P = .11). There was also no significant difference in survival between patients who underwent ECMO and those who did not undergo ECMO (OR, 0.48; P = .43).
The researchers also analyzed 13 studies with 1,002 patients that looked at ECMO as a bridge to transplant (mean age, 52.1; 52.2% male; 49.3% VV, 31.1% VA, 32.4% cardiopulmonary bypass). Mortality was lower in the VA group than in the VV group (odds ratio, 0.62; P = .04).
“VA ECMO is generally for sicker patients, so it’s odd that the patients who are on the more aggressive support had lower mortality. But it’s good, it says it works,” said Chris Carroll, MD, an intensivist at the University of Florida, Jacksonville, who was asked to comment on the study.
The finding may also be an artifact of bias in the retrospective data, according to Joshua Diamond, MD, who comoderated the session where the study was presented. He noted age, physical function, and illness severity, among other factors can play a role in decision-making. “I have a feeling that what you’re seeing is a very carefully selected patient population as opposed to a true mortality benefit with VA versus VV ECMO,” said Dr. Diamond, who is associate medical director of the Penn Lung Transplant Program in Philadelphia.
Another weakness of the study is that ECMO techniques and devices have changed over time, making some of the older data less relevant to current practice. Overall Dr. Diamond described the study as interesting, but “I’d like to see a bit more granularity of data to figure out who makes or doesn’t make a good candidate,” said Dr. Diamond.
Patients with ILD undergoing ECMO as a bridge to transplant had a higher 1-year posttransplant mortality than patients with other causes for transplant (OR, 1.78; P<.01). However, this finding relied on two retrospective studies using the UNOS database at different time points (2001-2012 and 2015-2020), leading to potential confounders and risk of bias.
Dr. Balasubramanian recognized the limitations of the analysis. “We do think that further prospective studies comparing various modalities would be essential, although it would be challenging,” he said.
Nevertheless, Dr. Guru said that his own center is changing its patient selection criteria for ECMO and will begin to collect prospective data: “I would say that in 12 months we’ll have our own data to support what we are doing.”
The study can also inform patients and family who are trying to make a potential end-of-life decision about pursuing aggressive ECMO therapy. “This study says that if you choose to pursue that more aggressive therapy, you may still have a good outcome. A patient might say, ‘Why am I going to go through all this? Is it just prolonging my death, or is there a chance of saving my life? I think what this study shows is that it does have potential of saving their life,” said Dr. Carroll.
Dr. Balasubramanian, Dr. Guru, and Dr. Carroll have no relevant financial disclosures.