Zonal organ allocation system and its impact on long-term outcomes after lung transplantation: a propensity score matched analysis†.
OBJECTIVE
Zonal organ allocation system comprises organ procurement by teams within a specific geographical area of each retrieval team. Therefore, in a substantial number of cases organs are retrieved by 'foreign' teams and are sent for transplantation to the implanting centre. The aim of this study was to assess the impact of zonal organ allocation system on early- and long-term outcomes after lung transplantation (LTx).


METHODS
Included were 331 consecutive patients who underwent LTx performed at Harefield Hospital between January 2007 and January 2015. Recipients were divided into two groups depending on the organ retrieval team: 204 (61.6%) patients were transplanted using lungs procured by our institutional team (institutional group), whereas 127 (38.4%) organs were retrieved by other teams (external group) from experienced transplant centres in the UK. To exclude selection bias and other confounders, a 1:1 propensity score-based matching procedure was performed resulting in a total number of 238 donors and recipients who were well matched for baseline characteristics. The primary end-points were overall survival after LTx and freedom from bronchiolitis obliterans syndrome (BOS). Secondary end-points were perioperative clinical characteristics as well as adverse events that occurred over the follow-up.


RESULTS
After propensity score matching all donor characteristics and all baseline recipient characteristics were statistically similar between the two groups. In terms of early postoperative results, both groups were statistically comparable. However, there was a trend towards higher incidence of primary graft dysfunction in the external group (P = 0.054). Regarding long-term results with up to 7 years of follow-up, the overall survival also appeared to be poorer in the external group; however, this difference did not reach statistical significance. The freedom from BOS over the long-term follow was significantly poorer in the external group (P = 0.040).


CONCLUSIONS
Despite excellent early outcomes the zonal allocation system might be associated with significantly poorer long-term outcomes in terms of freedom from BOS after bilateral LTx. Further research is needed to find the underlying factors leading to these results.
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.|Department of Cardiothoracic Surgery, University Hospital of Cologne, Cologne, Germany.
Mohamed
M
Zeriouh
Department of Cardiothoracic Surgery, University Hospital of Cologne, Cologne, Germany a.sabashnikov@gmail.com.
Anton
A
Sabashnikov
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Prashant N
PN
Mohite
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Bartlomiej
B
Zych
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Nikhil P
NP
Patil
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Diana
D
García-Sáez
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Achim
A
Koch
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Alexander
A
Weymann
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Simona
S
Soresi
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Jens
J
Wippermann
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Thorsten
T
Wahlers
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Fabio
F
De Robertis
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
Aron-Frederik
AF
Popov
Department of Cardiothoracic Transplantation and Mechanical Circulatory Support, Royal Brompton & Harefield NHS Foundation Trust, Harefield Hospital, Harefield, Middlesex, UK.
André R
AR
Simon
D000328:Adult; D001989:Bronchiolitis Obliterans / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival; D006801:Humans; D016040:Lung Transplantation / Q000379:methods; D008297:Male; D008875:Middle Aged; D055031:Primary Graft Dysfunction / Q000175:diagnosis* / Q000453:epidemiology; D057216:Propensity Score; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors; D014019:Tissue Donors; D009927:Tissue and Organ Procurement / Q000458:organization & administration*
Allocation system; Long-term outcomes; Lung transplantation; Mortality