The Importance of Segment 4 Anatomy on Outcomes Following Living Donor Left Lateral Segmentectomy.

BACKGROUND: During left lateral section (LLS) resection for live liver donation, the vascular inflow and the bile drainage of segment 4 (S4) are compromised. We investigated the long-term changes of S4 after donation and their potential prognostic impact on living liver donors. MATERIALS AND METHODS: This was a retrospective analysis of 42 consecutive left lateral (LLS, S2/3) liver resections for living donation. RESULTS: There were 25 female and 17 male donors. Median age was 33 y and median body mass index was 26. Median LLS, S2/3, volume was 262 cc, and median sS4 volume was 160 cc. Complications were encountered in three donors (7%). An independent extrahepatic S4 artery (S4A) (with a proximal left heptic artery or a right hepatic artery origin) was identified in 41% of the donors. Ligation of the independent S4A was not associated with the rate of post resection liver dysfunction, complications, or the degree of S4 atrophy. Having a dominant S4 portal triad pedicle feeding the right anterior sectors, segment 5/8, of the liver was associated with increased parenchymal damage as evidenced by a higher peak of alanine aminotransferase but was not associated with postoperative complications. The median degree of atrophy of S4 at 1 y post donation as noted on imaging was 66%. The presence of a dominant S4 portal triad pedicle and the peak alanine aminotransferase early postoperatively were both predictors of the degree of S4 atrophy post donation. CONCLUSIONS: The presence of an independent S4A or dominant S4 portal triad pedicle feeding the liver right anterior sectors, segment 5/8, should not be a contraindication for left lateral segment living donation.

Impact of the donor hepatectomy time on short-term outcomes in liver transplantation using donation after circulatory death: A review of the US national registry.

BACKGROUND: During the donor hepatectomy time (dHT), defined as the time from the start of cold perfusion to the end of the hepatectomy, liver grafts have a suboptimal temperature. The aim of this study was to analyze the impact of prolonged dHT on outcomes in donation after circulatory death (DCD) liver transplantation (LT). METHODS: Using the US national registry data between 2012 and 2020, DCD LT patients were separated into two groups based on their dHT: standard dHT (< 42 min) and prolonged dHT (≥42 min). RESULTS: There were 3810 DCD LTs during the study period. Median dHT was 32 min (interquartile range 25-41 min). Kaplan-Meier graft survival curves demonstrated inferior outcomes in the prolonged dHT group at 1-year after DCD LT compared to those in the standard dHT group (85.3% vs 89.9%; P < .01). Multivariate Cox proportional hazards models for 1-year graft survival identified that prolonged dHT [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.19 - 1.79], recipient age ≥ 64 years (HR 1.40, 95% CI 1.14 - 1.72), and MELD score ≥ 24 (HR 1.43, 95% CI 1.16 - 1.76) were significant predictors of 1-year graft loss. Spline analysis shows that the dHT effects on the risk for 1-year graft loss with an increase in the slope after median dHT of 32 min. CONCLUSION: Prolonged dHTs significantly reduced graft and patient survival after DCD LT. Because dHT is a modifiable factor, donor surgeons should take on cases with caution by setting the dHT target of < 32 min.

Torsion Does Not Affect Early Vein Graft Patency in the Rat Femoral Artery Model.

BACKGROUND: Torsion of vein grafts is a commonly cited reason for graft failure in clinical setting. Many microsurgery training courses have incorporated vein graft procedures in their curricula, and vein graft torsion is a common technical error made by the surgeons in these courses. To improve our understanding of the clinical reproducibility of practicing vein graft procedures in microsurgery training courses, this study aims to determine if torsion can lead to early vein graft failure in nonsurvival surgery rat models. METHODS: Sprague-Dawley rats were divided into five cohorts with five rats per cohort for a total of 25 rats. Cohorts were labeled based on degree of vein graft torsion (0, 45, 90, 135, and 180 degrees). Torsion was created in the vein grafts at the distal arterial end by mismatching sutures placed between the proximal end of the vein graft and the distal arterial end. Vein graft patency was then verified 2 and 24 hours postoperation. RESULTS: All vein grafts were patent 2 and 24 hours postoperation. At 2 hours, the average blood flow rate measurements for 0, 45, 90, 135, and 180 degrees of torsion were 0.37 ± 0.02, 0.38 ± 0.04, 0.34 ± 0.01, 0.33 ± 0.01, and 0.29 ± 0.02 mL/min, respectively. At 24 hours, they were 0.94 ± 0.07, 1.03 ± 0.15, 1.26 ± 0.22, 1.41 ± 0.11, and 0.89 ± 0.15 mL/min, respectively. CONCLUSION: Torsion of up to 180 degrees does not affect early vein graft patency in rat models. To improve the clinical reproducibility of practicing vein graft procedures in rat models, we suggest that microsurgery instructors assess vein graft torsion prior to clamp release, as vessel torsion does not seem to affect graft patency once the clamps are removed.

DCD Hepatitis C Virus-positive Donor Livers Can Achieve Favorable Outcomes With Liver Transplantation and Are Underutilized.

BACKGROUND: Hepatitis C virus (HCV)-positive donors (antibody-positive [Ab + ] or nucleic acid test positive [NAT + ] donors) have been underutilized. The aim of this study was to evaluate the utilization of livers from HCV-positive with donation after circulatory death (DCD) and to assess outcomes in recipients of these grafts. METHODS: Data between 2015 and 2019 were obtained from the United Network for Organ Sharing database. The utilization rates and graft survival among 8455 DCD liver and nonliver donors and 2278 adult DCD liver transplantation (LT) recipients were reviewed on the basis of donor HCV Ab/NAT status. RESULTS: The utilization of Ab + /NAT - donors <40 y and Ab + /NAT + donors ≥40 y was low than utilization of HCV-negative donors ( P < 0.001). Multivariate analysis identified HCV status (odds ratio [OR], 1.62; 95% confidence interval [CI], 1.06-2.48 in Ab + /NAT - , and OR, 1.49; 95% CI, 1.09-2.05 in Ab + /NAT + ) as an independent predictor of nonutilization of liver grafts. The rate of significant liver fibrosis was comparable in Ab + /NAT - (3.5%; P = 0.84) but was higher in Ab + /NAT + (8.7%; P = 0.03) than that in Ab - /NAT - donors. Kaplan-Meier survival curves demonstrated comparable 3-y patient survival in recipients of HCV-positive grafts compared with recipients of HCV-negative grafts ( P = 0.63; 85.6% in Ab - /NAT - , 80.4% in Ab + /NAT - , and 88.7% in Ab + /NAT + ). CONCLUSIONS: Patient and graft survival rates are similar between HCV-positive and HCV-negative DCD LT. However, HCV-positive donors are particularly underutilized for DCD LT.

Reappraisal of Donor Age in Liver Transplantation: NASH as a Potential Target to Safely Utilize Old Liver Grafts.

BACKGROUND: With the chronic shortage of donated organs, expanding the indications for liver transplantation (LT) from older donors is critical. Nonalcoholic steatohepatitis (NASH) stands out because of its unique systemic pathogenesis and high recurrence rate, both of which might make donor selection less decisive. The present study aims to investigate the usefulness of old donors in LT for NASH patients. METHODS: The retrospective cohort study was conducted using the Scientific Registry Transplant Recipient database. The cohort was divided into 3 categories according to donor age: young (aged 16-35), middle-aged (36-59), and old donors (60-). Multivariable and Kaplan-Meier analyses were performed to compare the risk of donor age on graft survival (GS). RESULTS: A total of 67 973 primary adult donation-after-brain-death LTs (2002-2016) were eligible for analysis. The multivariable analysis showed a reduced impact of donor age on GS for the NASH cohort (adjusted hazard ratio = 1.13, 95% confidence interval, 1.00-1.27), comparing old to middle-aged donors. If the cohort was limited to NASH recipients plus 1 of the following, recipient age ≥60, body mass index <30, or Model of End Stage Liver Disease score <30, adjusted hazard ratios were even smaller (0.99 [0.84-1.15], 0.92 [0.75-1.13], or 1.04 [0.91-1.19], respectively). Kaplan-Meier analysis revealed no significant differences in overall GS between old- and middle-aged donors in these subgroups (P = 0.86, 0.28, and 0.11, respectively). CONCLUSIONS: Donor age was less influential for overall GS in NASH cohort. Remarkably, old donors were equivalent to middle-aged donors in subgroups of recipient age ≥60, recipient body mass index <30, or Model of End Stage Liver Disease score <30.

Two hundred and fifty-one right hepatectomies for living donation: Association between preoperative risk factors, hepatic dysfunction, and complications.

BACKGROUND: Donor safety is essential in living donor liver transplantation. In this study we assessed the association among perioperative factors, liver dysfunction, and complications in 251 consecutives right hepatectomies for living donation. METHODS: Retrospectively collected data from a prospectively assembled cohort of 251 consecutive living donors who underwent right hepatectomy between 1999 and 2020 were evaluated. RESULTS: Median age was 36 years; 54% were men. There was a statistically significant relationship between standardized liver volume by body surface area and the volumes calculated by imaging, weighting, and volume displacement. (r2 = 0.40, r2 = 0.34, and r2 = 0.34, respectively), with the relationship between standardized liver volume and liver volume by imaging being the strongest. The median remnant liver volume was 35%. Fifty-eight donors (23%) developed postoperative hepatic dysfunction, which was associated with increased length of stay (P = .04), and complications (P < .01). Men had a 2.5 times higher chance of developing postoperative hepatic dysfunction. Age >50 years was an independent predictor of increased bilirubin at postoperative day 4 (P < .01), and remnant liver volume was inversely associated with higher peak international normalized ratio (P < .01). Eighty-one donors (32%) experienced complications. Postoperative hepatic dysfunction was associated with 2.4 times higher chances of complications (odds ratio = 2.4, P < .01). CONCLUSION: Early postoperative hepatic dysfunction is associated with the development of post-live liver donor complications. A thoughtful balancing of preoperative risk factors for postoperative hepatic dysfunction may indeed and by association reduce postoperative complications.

The neural substrates of driving at a safe distance: a functional MRI study.

An important driving skill is the ability to maintain a safe distance from a preceding car. To determine the neural substrates of this skill we performed functional magnetic resonance imaging of simulated driving in 21 subjects. Subjects used a joystick to adjust their own driving speed in order to maintain a constant distance from a preceding car traveling at varying speeds. The task activated multiple brain regions. Activation of the cerebellum may reflect visual feedback during smooth tracking of the preceding car. Co-activation of the basal ganglia, thalamus and premotor cortex is related to movement selection. Activation of a premotor-parietal network is related to visuo-motor co-ordination. Task performance was negatively correlated with anterior cingulate activity, consistent with the role of this region in error detection and response selection.