Editorial comment: Merits of cadaveric lobar lung transplantation.

Potential lung transplant recipients of small stature and those with reduced pleural space, for example, with pulmonary fibrosis, typically have a longer waiting time for donor lungs of suitable size. Cadaveric lobar lung transplantation (CLLT) has been increasingly employed to expand the donor pool for such patients who might not survive the lengthy wait for a whole lung donor. Subsequent to the initial reports of successful lobar transplantation by Bisson et al. [1, 2] two decades ago, centres including Vienna [3], Spain [4], France [5] and more recently Australia [6] have reported their experience. The present series from the University Hospital, Zurich [7] is a valuable addition to the existing literature. These studies suggest that CLLT has a long-term survival comparable with lung transplantation. We have selectively performed more than 20 CLLT at our institution in the adult lung transplant programme and have also found favourable results (unpublished data). Strategies to downsize donor lungs in the presence of donor– recipient (D–R) size discordance include either parenchymal wedge resection or anatomical lobectomy. Lobectomy can either be performed before (back table) or after implantation. CLLT, in the true sense, refers to the strategy of back-table lobectomy and implantation of a single lobe of the donor left lung or one or two lobes of the donor right lung. The initial reported experience of CLLT was described using the split donor left lung as it was felt to be technically easier. The donor left lower lobe was placed in the recipient’s left side and donor left upper lobe in the recipient’s right side. Ideally, in such a situation, the right lung can go to a different recipient. However, this requires tremendous co-ordination between the organ procurement organizations and availability of appropriate recipients. More commonly, the decision to downsize lungs is made intraoperatively after both lungs are received by the recipient centre. Nevertheless, knowing that CLLT is a viable option makes it easier to accept lungs from larger donors for small-statured recipients with higher acuity. Unfortunately, due to the relative urgency of transplant, recipients deemed candidates of CLLT may be at higher risk and have more haemodynamic instability during the reperfusion phase. Hence, the decision to downsize donor lungs in these patients is always challenging. One dilemma is whether to perform parenchymal wedge resection or anatomical lobectomy. Another is whether to do the downsizing prior to transplant or after reperfusion. For mild-to-moderate size discordance, peripheral wedge resection following reperfusion is preferable. Most of the middle lobe and lingula can easily be removed by stapled wedge resection. If the lungs are still too big, lower lobe wedge resections can be further performed. If the patient is unstable, the skeletal chest can be left open and the skin closed while deferring downsizing of the donor lung until a later time when the condition of the recipient has improved. Hence, postimplantation downsizing has the advantage of establishing respiratory stability prior to removing lung allograft tissue. Removing a large portion of the donor lung tissue prior to implantation does increase the chances of post-transplant respiratory failure, particularly in the setting of primary graft dysfunction transplantation [8]. Factors such as ischaemia time, distance from procurement centre, highrisk donor and recipient stability should all be taken into account when considering downsizing at the time of the initial procedure. CLLT is a good option for severe D–R discordance, because having long deep staple lines from multiple wedge resections adds the risk of prolonged air leakage or breakdown. Furthermore, CLLT has the same technical principles and anastomoses as whole lung transplant. Although a lobectomy on a collapsed lung performed on the back table is challenging and requires the presence of another surgeon to prevent cold ischaemia time, it is still preferable to a lobectomy following reperfusion. With this strategy, the anastomosis is performed between the donor lobar bronchus and recipient main bronchus and avoids the additional bronchial staple line that is created if a lobectomy is performed after the implantation. In addition, due to the much smaller recipient size, the recipient’s main bronchus has a reasonable size match to the donor lobar bronchus. It is noteworthy that there were no anastomotic complications in this current series. This is likely due to the fact that all anastomoses were performed to the short donor lobar bronchus. In the recent report by Marasco et al .[ 6], the authors describe some anastomotic complications, including a lower lobe stump fistula, when a main donor bronchial anastomotic technique was employed. We have had the same experience and we agree with the technique in this report. Also, transplanting an oversized lung in a small chest impairs visualization and, therefore, back-table lobectomy makes the implantation easier. Although lobar bronchi have more tenuous blood supply, the published series do not reveal this to be a major problem.