Clinical implications

Over the last decade, Ex-Vivo Lung Perfusion (EVLP) has evolved from an experimental lab procedure to become an indispensable semi-elective clinical routine which is revolutionizing donor lung assessment at many leading lung transplant centers.

Initially developed to more reliably and objectively evaluate lung function and thereby assess the Reject/Accept status of donor lungs for transplantation, EVLP is now rapidly emerging as a means of further improving or treating sub-standard/marginal donor lungs to further expand the effective donor lung pool and reduce mortality on the lung transplant waiting list. Not surprisingly, as with most “revolutions-in-progress”, a number of controversies and caveats have arisen over the last few years as to how best to perform and interpret EVLP and associated lung preservation issues.

There are currently 3 principal variants of EVLP. The main differences in protocol are summarized in the following fig (from table 2 Munshi L, Keshavjee S, Cypel M, Lancet, 2013).

Supporting clinical data

After extensive experimental research, the use of EVLP has been successfully introduced into clinical practice. The first lung to be successfully transplanted after EVLP was in Lund, Sweden in 2001 and the protocol was later modified for long-term assessment by the group in Toronto, Canada. Centers worldwide have implemented EVLP in their clinical programs following the Toronto protocol either using the XPS™ or a manual approach. Published reports from a number of individual centers show favorable clinical outcomes and clinical trials confirm these results.

Landmark studies confirm long-term safety of EVLP

The HELP Study

The HELP study, completed 2010 in Toronto, published the results of their ongoing use of EVLP at their site in 2012(JCTVS. 2012 Nov;144(5):1200-6). Reviewing the results of 50 consecutive lung transplantations performed after warm EVLP by the Toronto group, the authors concluded that 4-hour normothermic acellular EVLP is safe and provides similar outcomes compared with conventionally selected and transplanted donor lungs.

Good interim results presented – The NOVEL Study
The NOVEL study was the first prospective, multicenter clinical trial designed to evaluate the safety of Ex Vivo Lung Perfusion (EVLP) as a method to evaluate and identify good quality grafts from lungs previously rejected for transplantation.The one-year follow up of the study showed that EVLP, using the integrated XPS™ circuit with STEEN Solution™ as perfusate, is a safe diagnostic tool to screen the unused donor pool in order to increase the percentage of lungs transplanted.

Allowing for standardization of EVLP

XPS™ was developed to provide transplantation teams with a consistent and easy-to-use method of performing EVLP in the hospital. The objective was to develop an automated perfusion system that would allow for standardization of EVLP, without interfering with the need for clinical flexibility.

The donor lungs are transported according to the individual standard protocol.