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Donor lungs from smokers led to transplant outcomes similar to those involving lungs of nonsmokers, British transplant specialists reported.
Survival without bronchiolitis obliterans syndrome (BOS) ranged from 89% to 94% at 1 year and from 73.5% to 79% at 3 years in patients who received donor lungs from nonsmokers or smokers, including heavy smokers. Kaplan-Meier survival estimates also did not differ significantly by donor lung during follow-up to 5 years.
The results have implications for expanding the donor pool for lung transplantation, Anton Sabashnikov, MD, of the Royal Brompton and Harefield hospitals in Middlesex, England, reported in Annals of Thoracic Surgery.
"In our experience, history and extent of donor smoking do not significantly affect early and midterm outcomes after lung transplantation," the authors concluded. "Although this finding does not obviate the need for longer-term observation, donor lungs from even heavy smokers may not per se contraindicate lung transplantation and may provide a valuable avenue for expanding donor organ availability."
A shortage of organ donors for lung transplantation leads to significant mortality among patients on the wait list. Data from the UK Transplant Registry have shown that 20% of wait-listed patients receive donor lungs within 6 months, increasing to 51% by 3 years. However, about 30% of patients die while awaiting donor lungs, the authors noted.
To deal with the shortage of donor lungs, transplantation specialists have turned to multiple strategies, including use of lungs from extended-criteria donors, such as smokers.
A smoking history of <20 pack-years traditionally has been accepted as a criterion for an ideal donor, the authors continued. A smoking history beyond that cutoff puts a donor into the extended-criteria category. Overall survival in the current study ranged between 78% and 95% and 3-year survival from 68.2% to 82.1%. None of the differences achieved statistical significance.
Use of extended-criteria donor lungs creates a conundrum of sorts.
"Given the prevalence of smoking in the general population, and consequently in the organ donation pool, a policy of refusal to use lung allografts from smokers would have a profound impact on the number of available organs," the authors said. "Conversely, the risk that a positive smoking history in lung donors could adversely affect transplant outcomes causes concern."
To examine both sides of the conundrum, Sabashnikov and colleagues reviewed data for all lung transplantations performed at their center from 2007 to 2012. In particular, they explored the relationship between donor smoking history and several key transplantation outcomes.
The analysis comprised 237 lung transplantation procedures. Investigators separated donors into three categories: nonsmokers (N=123), smokers (N=68), and heavy smokers (N=41). Heavy smoking was defined as >20 pack-years (20 cigarettes a day for more than 20 years). Five donors were excluded because of missing information about smoking history.
The primary endpoints were overall survival after transplantation and survival free of BOS, a life-threatening inflammatory/fibrotic condition that can occur in transplanted lungs.
Secondary outcomes included oxygenation status (paO2/FiO2) at the end of transplant and at 24, 48, and 72 hours; duration of mechanical ventilation, intensive care unit (ICU) and total hospital stay; and need for postoperative extracorporeal membrane oxygenation.
The most notable difference among the three donor groups was the older age of heavy smokers (47.9 years versus 42.5 and 37.8 for nonsmokers and less-than-heavy smokers, P<0.001). Transplant recipients did not differ with respect to age, height, weight, total lung capacity, or preoperative use of extracorporeal membrane oxygenation.
Women accounted for a higher proportion of patients who received lungs from nonsmokers (54.5%).
The paO2/FiO2 ratio did not differ by the source of donor lungs at any time point. Postoperative BOS occurred in a similar proportion of patients who received donor lungs from the three categories of smoking history: 14% in nonsmoker group, 19% in the smoker group, and 21% in the heavy-smoker group.
Lung transplantation criteria in the U.S. also allow for donor lungs from smokers, including heavy smokers, said Dan Kreisel, MD, PhD, of Washington University in St. Louis.
"In light of the severe shortage of donor organs, I think more and more centers are considering organs that traditionally one would not have considered, especially in cases where death is the certain outcome of the recipient if he or she does not get a donor organ," Kreisel told MedPage Today.
The possibility that cancer or another serious disease could evolve in a donor lung from a smoker is a concern but has rarely occurred. Considering that lung transplantation is a life-saving procedure for patients, most are willing to take any risks associated with donor lungs from smokers, said Sasha Krupnik, MD, also of Washington University.
"It has been our policy at our institution, and I think at other places, that we'll generally avoid using lungs from patients with a heavy smoking history for our younger patients, such as those with cystic fibrosis," said Krupnik. "But if you have someone who is in the late 60s, who is getting transplanted for emphysema due to smoking or due to idiopathic pulmonary fibrosis, our threshold for using lungs with a heavy smoking history is a little lower."
Donor lungs from heavy smokers undergo a more extensive evaluation for the presence of abnormalities or diseases, including a CT scan, Kreisel added.
The study has a lot of relevance for lung transplantation in the U.S., which increasingly involves use of lungs from smokers, according to Christian Bermudez, MD, of the University of Pittsburgh. In an article published last year, Bermudez and colleagues reported that more than half of lung donors at their center had some smoking history, ranging from minimal to heavy.
"It has been well documented that lungs from donors who are smokers with a history of less than 2o pack-years can be used safely," said Bermudez. "Occasionally, we explore use of lungs from donors who have a heavy smoking history, more than 20 pack-years.
"As we reported last year, outcomes with donor lungs from patients with a smoking history of less than 20 pack-years or between 20 and 40 pack-years were similar to those we observed with lungs from nonsmokers. Eventually, we could detect some beneficial effect in terms of preventing primary lung dysfunction."
A small number of cases involved lungs from smokers with more than 40 pack-years of smoking. Those procedures were associated with a significantly higher incidence of severe lung dysfunction and significantly higher mortality at 1 and 3 years, Bermudez added.
The authors disclosed no relevant relationships.
- Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner
Annals of Thoracic SurgerySource Reference: Sabashnikov A, et al "Influence of donor smoking on midterm outcomes after lung transplantation" Ann Thorac Surg 2014; 97: 1015-1021.