Lobar lung transplantation from deceased donors: A systematic review

AIM To systematically review reports on deceased-donor-lobar lung transplantation(dd LLTx) and uniformly describe sizematching using the donor-to-recipient predicted-total lung-capacity(pT LC) ratio. METHODS We set out to systematically review reports on ddL LTx and uniformly describe size matching using the donorto-recipient pT LC ratio and to summarize reported oneyear survival data of ddL LTx and conventional-LTx. We searched in Pub Med, CINAHL via EBSCO, Cochrane Database of Systematic Reviews via Wiley(CDSR),Database of Abstracts of Reviews of Effects via Wiley(DARE), Cochrane Central Register of Controlled Trials via Wiley(CENTRAL), Scopus(which includes EMBASE abstracts), and Web of Science for original reports on ddL LTx. RESULTS Nine observational cohort studies reporting on 301 ddL LTx met our inclusion criteria for systematic review of size matching, and eight for describing one-year-survival. The dd LLTx-group was often characterized by high acuity;however there was heterogeneity in transplant indications and pre-operative characteristics between studies. Data to calculate the pT LC ratio was available for 242 ddL LTx(80%). The mean pT LCratio before lobar resection was1.25 ± 0.3 and the transplanted pT LCratio after lobar resection was 0.76 ± 0.2. One-year survival in the ddL LTxgroup ranged from 50%-100%, compared to 72%-88%in the conventional-LTx group. In the largest study ddL LTx(n = 138) was associated with a lower one-year-survival compared to conventional-LTx(n = 539)(65.1% vs84.1%, P < 0.001). CONCLUSION Further investigations of optimal donor-to-recipient size matching parameters for ddL LTx could improve outcomes of this important surgical option.

Donor to recipient sizing in thoracic organ transplantation

Donor-to-recipient organ size matching is a critical aspect of thoracic transplantation. In the United States potential recipients for lung transplant and heart transplant are listed with limitations on donor height and weight ranges, respectively. Height is used as a surrogate for lung size and weight is used as a surrogate for heart size. While these measures are important predictors of organ size, they are crude surrogates that fail to incorporate the influence of sex on organ size. Independent of other measures, a man's thoracic organs are approximately 20% larger than a woman's. Lung size can be better estimated using the predicted total lung capacity, which is derived from regression equations correcting for height, sex and age. Similarly, heart size can be better estimated using the predicted heart mass, which adjusts for sex, age, height, and weight. These refined organ sizing measures perform better than current sizing practice for the prediction of outcomes after transplantation, and largely explain the outcome differences observed after sex-mismatch transplantation. An undersized allograft is associated with worse outcomes. In this review we examine current data pertaining to size-matching in thoracic transplantation. We advocate for a change in the thoracic allocation mechanism from a height-or-weightbased strategy to a size-matching process that utilizes refined estimates of organ size. We believe that a size-matching approach based on refined estimates of organ size would optimize outcomes in thoracic transplantation without restricting or precluding patients from thoracic transplantation.