A retrospective review of all sequential dual-organ living donors at the Ajmera Transplant Centre, Toronto General Hospital, University Health Network (UHN), Toronto, Ontario, Canada was performed. The study period began at program inception and extended through December 2025. All living donors provided written informed consent for data collection under protocols approved by the UHN Research Ethics Board.

This study was designed as a donor-focused analysis. Sequential dual-organ living donors were defined as individuals who completed two separate living donor operations: one living donor hepatectomy (left lateral segment, left lobe, or right lobe) and one living donor nephrectomy (left or right sided, laparoscopic or open). Outcomes of interest (detailed below) included donor demographic characteristics, the nature and sequence of each donation, the interval between them, participation in kidney paired donation, operative approach, perioperative complications, length of stay, and perioperative renal biochemistry. Recipient characteristics and post-transplant recipient outcomes were not collected as the focus of this study was to evaluate the perioperative outcomes of sequential dual donors in relation to their sequence of donation.

None of the donors in our cohort expressed a desire to donate two organs at the outset. The sequence of organ donation was therefore determined by individual donors without input from our team, and they were evaluated for either liver or kidney donation first based upon their initial presentation as willing liver or kidney donors, respectively. Evaluation for the subsequent living organ donation was conducted sequentially and independently of the first at the request of the donor. Evaluations for liver and kidney donation were conducted according to standard protocols, as previously described [11–13]. The medical, nursing, and psychosocial teams performing the evaluation of liver and kidney donors at our center are separate and distinct. The surgeons involved in living liver donation procedures and living kidney donation procedures are also distinct except for one surgeon who performs both.

Selection of which kidney to donate was driven by relative function. If function was symmetric, the anatomically less complex kidney was chosen. For liver donation, the type of hepatectomy was selected to maximize the donor’s functional liver remnant (FLR) and provide an adequate graft-to-recipient weight ratio (GRWR). If the left lobe (LL) or left lateral segment (LLS) anatomy was not favorable for donation, or if a suitable recipient for a LL/LLS graft was not available within the donor’s donation timeline, then right lobe donation was considered. Prior organ donation was not a factor in determining the laterality of liver or kidney donation.

Voluntary participation in Canada’s national kidney paired donation (KPD) program was offered to all anonymous nondirected kidney donors as well as directed living kidney donors who were found to be incompatible with their intended recipients.

All living donor hepatectomies were performed through an upper midline incision. Strict intravenous fluid restriction was implemented during all donor hepatectomy procedures to minimize central venous pressure, regardless of prior kidney donation status. Blood pressure targets were achieved with vasopressor administration until parenchymal transection was completed, after which resuscitation with intravenous crystalloids was initiated and vasopressors were rapidly weaned off. All living donor nephrectomies were performed laparoscopically, except in two in whom a planned open mini-incision was undertaken because of anticipated adhesions related to prior hepatectomies.

Variables included donor demographics and age at each donation, donor body mass index (BMI), comorbidities (presence of diabetes or hypertension), order of donation (liver-first vs. kidney-first), interval between donations, nature of each donation (directed vs. anonymous), participation in KPD, surgical approach and side/segment donated, length of stay, perioperative complications for each procedure, and perioperative renal biochemistry.

Descriptive statistics were used for demographics and operative characteristics. Continuous variables were summarized using medians and interquartile ranges as appropriate. Between-group comparisons were assessed using the Mann-Whitney U test. Statistical significance was defined a priori as p < 0.05.

We identified 24 sequential dual-organ living donors during the study period, representing approximately 0.5% of all living donors in our center. Donors were a median of 40.7 years old at the time of their first donation (IQR 29.9–48.2 years) and 44.0 years old at the time of their second donation (IQR 32.5–49.8 years). The median interval between donations was 2.0 years (IQR 1.1–4.2 years). A majority of the donors were female (67%). Median donor BMI was 24.3 (IQR 22.8–27.6). None of the donors had hypertension or diabetes mellitus. Detailed cohort characteristics are summarized in Tables 1, 2.

Of the cohort, 42% (10/24) underwent liver donation first followed by kidney donation. The remainder of the cohort (14/24) donated a kidney first and subsequently underwent living donor hepatectomy. A high proportion of donors (88%, n = 21) performed at least one donation anonymously. Twelve living donors donated both organs in an anonymous nondirected fashion, nine donated one organ anonymously and directed the other, and three directed both donations. Twelve of 24 kidney donations were anonymous nondirected while 21 of 24 liver donations were anonymous nondirected. Ten out of 24 donors (42%) participated in KPD, thereby enabling additional transplants. Ten donors underwent living kidney donation at another transplant center in Canada prior to seeking liver donation at our center; nine of ten sought anonymous nondirected liver donation, while one was directed. All liver donation procedures were performed at our center. No liver-first donors subsequently donated a kidney at another transplant center in Canada.

Liver donations included left lateral segment hepatectomy (n = 10), left lobe hepatectomy (n = 6), and right lobe hepatectomy (n = 8). All hepatectomies were performed through an upper midline incision. As discussed earlier, graft selection was individualized. In the kidney-first cohort (n = 14), five donated an RL graft, four donated an LLS graft, and five donated an LL graft. In the liver-first cohort (n = 10), three donated an RL graft, six donated an LLS graft, and one donated an LL graft.

Kidney donations were predominantly left-sided (88%). The laparoscopic approach was used in all except two donors. The first kidney-after-liver donor in our series underwent a planned open left nephrectomy due to anticipated adhesions from prior left lateral hepatectomy and lack of confidence about attempting a laparoscopic nephrectomy at an early stage in the evolution of our program. The only individual to donate a right kidney after right hepatectomy underwent a planned open right nephrectomy due to anticipated adhesions to the cut surface of the liver in the right upper quadrant that could complicate a laparoscopic approach.

None of the donors experienced a perioperative complication in either of their two procedures. The median LOS after living donation of a liver graft was 5.5 days (IQR 4.0–6.0) in the liver-first cohort and 5.0 days (IQR 4.0–5.0) in the liver-second cohort (Figure 1A). The LOS did not differ significantly (p = 0.42). The median length of stay (LOS) after living donation of a kidney graft was 2.5 days (IQR 2.0–3.0) in the kidney-first cohort and 3.5 days (IQR 2.3–4.0) in the kidney-second cohort (Figure 1B). This finding was not statistically significant (p = 0.07). None of the donors experienced acute kidney injury post donation (Figure 2). The type of donor hepatectomy performed did not impact renal function in prior kidney donors.

This is the largest single-center series of 24 sequential dual-organ living donors reported to date. Our granular series describes a donor population that is young, predominantly female, uniformly free of hypertension and diabetes, and characterized by a high prevalence of anonymous donation.

Twenty-one of 24 donors (88%) performed at least one donation anonymously and 12 donated both organs anonymously. This reflects the systematic development of anonymous living liver donation at our center [14–16]. As such, this led a substantial proportion of our cohort to seek liver donation here after donating a kidney elsewhere.

Across 48 donor operations there were no perioperative complications, length of stay did not differ significantly by donation sequence, and none of the liver-after-kidney donors developed acute kidney injury. Five liver-after-kidney donors underwent right lobe donation without perioperative renal impairment despite highly restrictive intraoperative fluid administration, consistent with earlier reports of preserved renal function in this sequence [5, 10]. This does not support the suggestion that the volume of liver resected should be constrained in prior kidney donors [10]. However, the small sample size precludes an accurate estimation of risk, and these findings should be cautiously extrapolated to the broader population of prior living kidney donors.

These uniformly favorable outcomes should be interpreted in the context of an exceptionally healthy and highly selected donor cohort. All donors were fit and free of comorbidities. In donors returning for a second donation, more stringent thresholds for fitness and risk should apply.

Prior donor surgery rarely altered the operative approach to the second donation (kidney-first, n = 14; liver-first, n = 10). Laparoscopic nephrectomy was feasible in all prior liver donors except two, early in our experience, in whom a planned open mini-incision was undertaken for anticipated adhesions from ipsilateral prior hepatectomy with an unsuitable contralateral kidney.

Conversely, prior kidney donation did not influence the type of hepatectomy performed. Graft selection followed the usual principles of maximizing the donor’s FLR while providing a graft of adequate graft-to-recipient weight ratio. Prior donation should therefore inform operative planning and consent rather than constrain graft type or laterality.

No donor identified dual donation as an objective at first presentation. Each returned of their own accord. As such, the sequence observed reflects the order of presentation rather than the design of our program. For a candidate presenting with dual donation as an objective, our data do not support a prescriptive pathway.

Each sequence carries theoretical trade-offs: kidney-first places the lower-risk operation first, whereas liver-first avoids a complex hepatectomy in a donor with a solitary kidney. Sequence selection is best grounded in donor wishes, anatomy and physiologic reserve, recipient urgency, and center experience, with equipoise maintained across both options.

A median interval between donations of 2.0 years was observed in our cohort. Our current data at this point are insufficient to define a minimum interval policy between donations. However, a minimum interval of 6 months was considered appropriate to allow adequate physiological recovery and reassessment of psychosocial stability before a second donation.

Ten of 24 donors (42%) participated in kidney paired donation, so the yield from one individual’s decision may extend beyond two transplants, and integration of living liver donors into liver-paired exchange could extend it further [17]. No consensus guidance exists for donors who return, and we would support standards addressing selection, minimum interval, consent for cumulative risk, and a registry able to audit the sequential donation journey.

Limitations include the retrospective design, modest sample size, and the lack of long-term quality of life and functional outcomes. Follow-up was confined to the perioperative period, so long-term renal and hepatic function and the cumulative long-term risk of two donor operations remain unaddressed. We did not examine psychosocial drivers, donor identity, or health-related quality of life, all of which shape attitudes to donation [18], and our observations regarding anonymous donation are therefore descriptive rather than explanatory. This study was designed as a donor-specific analysis; therefore, recipient characteristics and post-transplant outcomes were not examined, nor was a comparator cohort of single-organ donors included. All of the above would be valuable in future multicenter studies to better contextualize the outcomes of sequential dual-organ donation.