“Hopefully, our paper will trigger a re-evaluation of these practices and lead to a more measured and valid approach to inform transplant decisions,” said Dr Reed. “Relying on a BODE score threshold for physicians to make the decision to refer for consideration for lung transplantation may still be good practice, but a more sophisticated approach should be taken [into account] by the transplant physicians responsible for counseling the patients and deciding when to actively list [them] for the surgery.”

Single vs Double Lung Transplants


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Despite improvements in survival for single lung transplantation for COPD, double lung transplants remain the rule for more than 57% of all COPD lung transplants.1 Single lung transplants in the 1970s often resulted in a mismatch of perfusion and ventilation with the native lung.1

Today’s surgeons, however, could be misguided by outdated evidence on single vs double transplants because many studies that demonstrated a greater survival with double vs single lung transplants were from single-center studies.1

In a more recent study of 3174 patients, Justin M. Schaffer, MD, and colleagues found that survival rates were in fact comparable between single and double lung transplant surgeries.5 In patients who had lung transplants between May 2005 and December 2012, the median survival for single lung transplant was 64.0 months (interquartile range, 25.2-88.7 months) vs 67.7 months for double lung transplant (interquartile range, 25.2-89.6 months; P =.23).5

Optimizing Outcomes Before, During, and After Transplant

One of the major factors in determining the success of transplant surgery is allograft ischemic time, or the time organs spend outside the donor before they are transplanted.6 Two notable advances in lung transplantation have been donation after circulatory death and ex vivo organ perfusion. The former allows for swifter donation, and the latter maintains organ function in transit, allowing for longer transit times.6 The latest lung transplant data from the ISHLT Registry based on 60,107 adult lung transplants recorded a median allograft ischemic time of 5.5 hours for bilateral lung transplants and 4.2 hours for single lung transplants.6

“Although lung transplant candidates with long ischemic times had higher unadjusted 30-day mortality, unadjusted long-term mortality was favorable,” explained lead author of the ISHLT registry report Daniel Chambers, MD, associate professor at the University of Queensland in Brisbane, Australia. “Whilst there may be many reasons for these differences, the overall message was that those patients receiving organs where the ischemic time is long (more than 6 hours) should not expect inferior long-term outcomes.”

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Despite the challenges facing patients with COPD and their pulmonologists, there are some ways clinicians can enhance their decision making on treatment and outcomes. “Identifying COPD for transplant referral and consideration requires multiple steps: 1) a patient with objectively severe disease based on imaging and spirometry, and 2) a patient whose quality of life is severely affected by their pulmonary symptoms,” advised Dr Diamond. “The added layer…for pulmonologists is understanding the complexities inherent in the lung allocation system, a system made more complex by the recent changes in donor allocation that may limit transplant opportunities for patients with lower lung allocation scores, a group that includes many COPD patients because of the lack of proven mortality benefit.”

Summary & Clinical Applicability

Although COPD is the leading indication for lung transplantation in the world, and second in the United States, there is a lack of consensus regarding the timing and type of transplant surgery. Even with the scant evidence available, clinicians need to educate patients with COPD about the benefits and risks of transplant surgery.

Limitations & Disclosures

Dr Chambers received travel support from Astellas Pharma, Inc. and serves as a consultant and speaker for Roche Ltd.

References

1. Siddiqui FM, Diamond JM. Lung transplantation for chronic obstructive pulmonary disease: past, present, and future directions. Curr Opin Pulm Med. 2018;24(2):199-204.

2. US Department of Health and Human Services. Organ Procurement and Transplantation Network Lung Allocation Score Calculator. https://optn.transplant.hrsa.gov/resources/allocation-calculators/las-calculator/. Accessed February 12, 2018.

3. Layton AM, Armstrong HF, Baldwin MR, et al. Frailty and maximal exercise capacity in adult lung transplant candidates. Respir Med. 2017;131:70-76.

4. Reed RM, Cabral HJ, Dransfield MT, et al. Survival of lung transplant candidates with COPD: BODE score reconsidered [published online October 17, 2017]. Chest. doi:10.1016/j.chest.2017.10.008

5. Schaffer JM, Singh SK, Reitz BA, Zamanian RT, Mallidi HR. Single- vs double-lung transplantation in patients with chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis since the implementation of lung allocation based on medical need. JAMA. 2015;313(9):936-948.

6. Chambers DC, Yusen RD, Cherikh WS, et al; for the International Society for Heart and Lung Transplantation. The Registry of the International Society for Heart and Lung Transplantation: Thirty-fourth Adult Lung And Heart-Lung Transplantation Report-2017; focus theme: allograft ischemic time. J Heart Lung Transplant. 2017;36(10):1047-1059.