‘Side-Mismatched’ Single Lung Transplantation Does Not Compromise the Transplant Outcomes

Abstract

Purpose There are controversies regarding which side of the lungs, under-perfused versus over-perfused to be replaced when performing single lung transplantation (LTx). Theoretically, under-perfused lung appears to be better replaced rather than over-perfused lung; however, occasionally over-perfused lung is chosen due to limited organ availability, size discrepancy between the sides, or anatomical complexity, and this is recognized as ‘side-mismatching’ in single LTx. This study aims at evaluating the impact of side-mismatching on transplant outcomes. Methods Graft side-mismatching was defined with a prospectively designed formula using baseline quantitative lung perfusion scan data, and the patients who underwent single LTx between January 2016 and June 2018 were stratified as either side-matched or side-mismatched. A retrospective review of the LTx database was used to obtain short- and mid-term outcomes as well as complications for those patients. Results Two hundred eighteen patients received single LTx between January 2016 and June 2018. Out of these, there were a total of 18 patients had a side-mismatched graft while those with a side-matched graft over the same time period were used as controls. There were no significant differences between the groups in their patients’ characteristics except more patients with age above 70 years old and less patients with secondary pulmonary hypertension noted in the side-mismatched group. While the size-mismatched group consisted of more patients who underwent right single than left single LTx and required more intraoperative cardiopulmonary support (25% vs. 8.2%, p<0.05), there were no significant differences in most postoperative major complications including duration mechanical ventilation and incidences of severe primary graft dysfunction. Actual survival at 1 year was not significantly different among the groups (86% vs. 88%). Conclusion Our data suggest that there is no evident increased risk or compromised post-transplant outcomes in performing side-mismatched single LTx when appropriate lung graft as well as intraoperative cardiopulmonary support is chosen. This strategy could optimize organ utilization increasing effective organ supply and decreasing waitlist mortality. In addition, this may contribute to avoiding the surgical or anatomical complexity leading to improved transplant outcomes. There are controversies regarding which side of the lungs, under-perfused versus over-perfused to be replaced when performing single lung transplantation (LTx). Theoretically, under-perfused lung appears to be better replaced rather than over-perfused lung; however, occasionally over-perfused lung is chosen due to limited organ availability, size discrepancy between the sides, or anatomical complexity, and this is recognized as ‘side-mismatching’ in single LTx. This study aims at evaluating the impact of side-mismatching on transplant outcomes. Graft side-mismatching was defined with a prospectively designed formula using baseline quantitative lung perfusion scan data, and the patients who underwent single LTx between January 2016 and June 2018 were stratified as either side-matched or side-mismatched. A retrospective review of the LTx database was used to obtain short- and mid-term outcomes as well as complications for those patients. Two hundred eighteen patients received single LTx between January 2016 and June 2018. Out of these, there were a total of 18 patients had a side-mismatched graft while those with a side-matched graft over the same time period were used as controls. There were no significant differences between the groups in their patients’ characteristics except more patients with age above 70 years old and less patients with secondary pulmonary hypertension noted in the side-mismatched group. While the size-mismatched group consisted of more patients who underwent right single than left single LTx and required more intraoperative cardiopulmonary support (25% vs. 8.2%, p<0.05), there were no significant differences in most postoperative major complications including duration mechanical ventilation and incidences of severe primary graft dysfunction. Actual survival at 1 year was not significantly different among the groups (86% vs. 88%). Our data suggest that there is no evident increased risk or compromised post-transplant outcomes in performing side-mismatched single LTx when appropriate lung graft as well as intraoperative cardiopulmonary support is chosen. This strategy could optimize organ utilization increasing effective organ supply and decreasing waitlist mortality. In addition, this may contribute to avoiding the surgical or anatomical complexity leading to improved transplant outcomes.