Ischemia Time Research Articles

326.3: Is it worth using hearts with more than 4 hours ischemic time? Results from 528 consecutive heart transplants at a reference center in Brazil.

326.3: Is it worth using hearts with more than 4 hours ischemic time? Results from 528 consecutive heart transplants at a reference center in Brazil.

Outcomes of single vs double lung retransplantation in patients with cystic fibrosis

ObjectivePatients requiring lung transplant for cystic fibrosis (CF) may require retransplant due to limited graft survival and otherwise excellent life expectancy. Optimal transplant strategy for this population, including single vs. double lung retransplant, has not been established. MethodsWe performed a retrospective analysis of the UNOS/OPTN database to identify adult lung retransplant recipients from 2005-2021 with a primary diagnosis of CF. Patients were stratified by retransplant type (single lung [re-SLTx] vs. double lung [re-DLTx] retransplant). Descriptive statistics, Kaplan-Meier survival analysis, and multivariable Cox regression were performed. ResultsFrom 2005-2021, 384 recipients underwent retransplant after an initial transplant for an indication of CF; more recipients underwent re-DLTx (N=337 [87.8%]) than re-SLTx (N=47 [12.2%]). The median (IQR) time from initial transplant to retransplant was similar between re-SLTx and re-DLTx recipients (4.4 [2.9-8.6] vs. 4.6 [2.6-7.4] years, p=0.73). Ischemic time was shorter and lung allocation score was lower for re-SLTx than re-DLTx recipients. Median survival after retransplant was significantly shorter for re-SLTx vs. re-DLTx recipients (2.0 [95% CI 1.2-3.5] vs. 4.3 [95% CI 3.5-6.1] years post-retransplant, p=0.008). Median survival for adults with CF undergoing primary transplant for CF in the same period was 9.1 (8.5-9.9) years. After adjusting for donor and recipient characteristics, re-SLTx in patients with CF was associated with 88% higher hazard of mortality than re-DLTx (aHR=1.88 [95% CI 1.28-2.78], p=0.001). ConclusionsIn this analysis of lung retransplant in recipients with CF, re-SLTx was associated with a higher hazard of mortality compared to re-DLTx, supporting re-DLTx as treatment for this population.

Severe early graft dysfunction post-heart transplantation: Two clinical trajectories and diastolic perfusion pressure as a predictor of mechanical circulatory support

BackgroundSevere early graft dysfunction (EGD) is defined by mechanical circulatory support (MCS) <24 hours of heart transplantation (HT). We classified severe EGD based on timing of post-HT MCS: ‘Immediate’ intra-operative vs ‘Delayed’ post-operative MCS (after admission into intensive care unit (ICU) from operating theatre). We hypothesised that (i) risk factors and clinical course differ between ‘Immediate’ and ‘Delayed’ MCS; and (ii) diastolic perfusion pressure (DPP=diastolic blood pressure-central venous pressure) and Norepinephrine equivalents (NE=sum of vasopressor doses), as measures of vasoplegia are related to ‘Delayed’ MCS. MethodsTwo-centre study of 216 consecutive patients who underwent HT. Recipient, donor, vasopressor doses and hemodynamic data at T0 and T6 (on admission and 6 hours after admission into ICU) were collected. ResultsOf the 216 patients, 67 patients had severe EGD (‘Immediate’ MCS: n=43, ‘Delayed’ MCS: n=24). The likelihood of ‘immediate’ MCS but not 'delayed' MCS increased with increasing warm ischemic and cardiopulmonary bypass times on multinomial regression analysis with ‘no MCS’ as the referent group. One-year mortality was highest in ’Immediate’ MCS vs ’no MCS’ and ‘delayed’ MCS (34.9% vs 3.4% and 8% respectively, P<0.001). Of the patients who had no immediate post-transplant MCS, DPP and NE at T6 were independently associated with subsequent 'delayed' MCS’. Sensitivity and specificity of NE ≥0.2mcg/kg/min for ‘Delayed’ MCS were 71% and 81%. Sensitivity and specificity of DPP of ≥40mmHg for No MCS were 83% and 74%. The discriminatory value of systemic vascular resistance for ‘Delayed’ MCS was poor. ConclusionRisk factors and one-year survival differed significantly between ‘Immediate’ and ‘Delayed’ post-HT MCS. The latter is related to lower DPP and higher NE, which is consistent with vasoplegia as the dominant pathophysiology.

Analyzing the Impact of CIT on the Largest Reported Cohort of Robotic Kidney Transplantation From the Deceased Donors.

Robotic-assisted kidney transplant (RAKT) has proven to be a successful approach for patients with morbid obesity and more centers are encouraged to apply robotic approach also for deceased donor kidney transplantation. Prolonged cold ischemia time (CIT) is accompanied by delayed graft function (DGF) and early graft loss after traditional open kidney transplant (OKT). This study examines the impact of CIT after robotic kidney transplantation on settings of deceased donation. We present a single-center retrospective analysis of 115 cases of RAKT and 128 cases of OKT from deceased donors performed from deceased donor from 2009 to July 2022. Cohort was divided in 3 groups based on CIT ("high" CIT > 15 h, n = 43; "medium" CIT 11-15 h, n = 38; "low" CIT< 11 h, n = 40). The subgroup analysis of DGF and CIT was performed. The median CIT in the cohort was 13.46 (7) h, and overall rate of DGF was 30.6%. The correlation between CIT and DGF was statistically significant (P = 0.008), and DGF negatively correlated with 1-y graft survival (P = 0.04). The rate of DGF was significantly different between the groups (P = 0.05). Results from our study demonstrate that the effect of CIT on DGF in settings of RAKT follows a similar pattern as in traditional OKT.

A novel arterial coupler with non-return snap-fit connection approach optimized arterial end-to-end anastomotic technique: An experimental study

PurposeHand-sewn anastomosis as the gold standard of vascular anastomosis cannot fully meet the requirements of vascular anastomosis in speed and quality. Various vascular couplers have been developed to ameliorate this situation. Most of them are mainly used for venous anastomosis rather than arterial anastomosis, even though it is generally acknowledged that in almost all operations involving vascular reconstruction, it is the arteries that need to be anastomosed faster and more accurately and not the veins. A dedicated device is needed for creating arterial anastomosis in an easy, timesaving, less damaging but reliable procedure. Therefore, we plan to develop a novel arterial coupler device and test pre-clinical safety and effectiveness. MethodsIn this cohort study, the rationality of this novel arterial coupler was preliminarily tested by finite element analysis before it was manufactured. Several factors restrict the use of vascular couplers in arterial anastomosis, such as arterial eversion, fixation, etc. The manufactured arterial couplers underwent in vitro and in vivo experiments. In vitro, isolated arteries of beagles were anastomosed with the assistance of an arterial coupler, and the anastomosed arteries were evaluated through anti-traction tests. In animal experiments, the bilateral femoral arteries of 5 beagles served as a control group. After dissection, the femoral artery on one side was randomly selected to be anastomosed with a quick arterial coupler (QAC) (QAC group), and the femoral artery on the other side was anastomosed by the same person using an end-to-end suture technique with a 6-0 Prolene suture (suture group). The bilateral femoral arteries of 5 beagles were used for coupler-assisted anastomosis and hand-sewn anastomosis in vivo, respectively. Success rate, blood loss, anastomotic time, clamp time, total operation time, and patency rate were recorded. The patency of anastomosed arteries was assessed using vascular Doppler ultrasound, electromagnetic flowmeter, and pathological examination (6 weeks after surgery). ResultsAs a novel arterial coupler, QAC was successfully designed and manufactured by using poly lactic-co-glycolic acid raw materials and 3-dimensions printing technology. Its rationality was preliminarily tested through finite element analysis and related mechanical analysis methods. The isolated arteries were successfully anastomosed with the assistance of QAC in vitro testing, which showed good anti-traction properties. In animal studies, QAC-assisted arterial anastomosis has superior profiles compared to hand-sewn anastomosis in anastomotic time (7.80 ± 1.41 vs. 16.38 ± 1.04 min), clamp time (8.80 ± 1.41 vs. 14.14 ± 1.57 min), and total operation time (46.64 ± 2.38 vs. 51.96 ± 3.65 min). The results of electromagnetic flowmeter, vascular Doppler ultrasound, and pathological examination showed that QAC-assisted anastomotic arteries were superior to hand-sewn arteries in terms of postoperative blood flow (16.86 ± 3.93 vs. 10.36 ± 0.92 mL/min) and vascular patency in 6 weeks after surgery. ConclusionQAC is a well-designed and easily maneuverable device specialized for end-to-end arterial anastomosis. Application of this device may decrease thermal ischemia time and improve the patency of anastomotic arteries, thus, improving outcomes.

PJY17 Impact of clinical risk factors, tumor characteristics, PADUA and RENAL scores on warm ischemia time during robot-assisted laparoscopic partial nephrectomy

PJY17 Impact of clinical risk factors, tumor characteristics, PADUA and RENAL scores on warm ischemia time during robot-assisted laparoscopic partial nephrectomy

Ischemia‐Free Liver Implantation Versus Normothermic Machine Perfusion: Evaluation of Feasibility and Security

ABSTRACTBackgroundFurther optimization and improvement of normothermic machine perfusion (NMP) is necessary, as it can still lead to ischemia injury in transplanted livers. We propose a novel method, termed ischemia‐free liver implantation (IFLI), which maintains a constant blood supply throughout both the preservation and implantation processes. This study aimed to evaluate the feasibility and safety of IFLI compared to NMP.MethodsThirty‐four recipients of IFLI and 17 recipients of NMP were enrolled. The recovery of liver function, complication rates, and survival outcomes were compared between the groups.ResultsThe mean cold ischemia time (CIT), anhepatic time, and surgical duration were 5.94 ± 0.41 h, 50.59 ± 2.10 min, and 439.32 ± 13.25 min for the IFLI group, and 6.29 ± 0.52 h, 54.65 ± 4.32 min, and 428.06 ± 22.04 min for the NMP group (p = 0.333, 0.086, and 0.135, respectively). The IFLI group had a significantly lower incidence of post‐reperfusion syndrome compared to the NMP group (8% vs. 58.8%, p &lt; 0.001), and the incidence rate of PNF was higher in the NMP group (p = 0.041).ConclusionIFLI, by maintaining constant blood supply during implantation, avoids re‐ischemia‐reperfusion injury (re‐IRI) and demonstrates improved postoperative liver function recovery, fewer complications, and greater safety compared to standard NMP.

Long-term Results of Valve-Sparing Aortic Root Replacement in Acute Type A Aortic Dissection

BackgroundValve preservation in acute type A aortic dissection (ATAAD) can be accomplished with root repair or replacement. Long-term valve durability with root repair has been established, but limited data exist regarding long-term durability of valve-sparing root replacement (VSRR). In this study, long-term results of VSRR were compared with root repair in ATAAD. MethodsFrom 2005 to 2023, 866 patients underwent ATAAD repair, of which 675 underwent root repair and 191 underwent root replacement (VSRR, n = 65; Bentall, n =126). VSRR patients were compared with 123 patients who underwent valve resuspension and root repair with postoperative echocardiograms ≥1 year. ResultsVSRR patients were younger (VSRR, 44 ± 11 years vs root repair, 55 ± 13 years; P < .001). Preoperatively, 57% of VSRR and 35% of root repair patients had moderate or more aortic insufficiency. Cardiopulmonary bypass and myocardial ischemia times were significantly longer in VSRR (P < .001). Postoperative echocardiograms with ≥1 year follow-up were analyzed in 58 VSRR patients with median follow-up of 4.8 years (interquartile range, 3-12 years) and in 123 root repair patients with median follow-up of 3.6 years (interquartile range, 3-8 years). At 10 years, VSRR patients had superior freedom from more than mild aortic insufficiency (VSRR, 91% vs root repair, 49%; P < .001). At 10 years, freedom from aortic valve replacement was equivalent (VSRR, 98% vs root repair, 92%; P = .269). ConclusionsVSRR provides equivalent long-term valve durability as root repair in ATAAD, even in patients with moderate or severe aortic insufficiency. In select young patients who require root replacement during ATAAD repair, VSRR represents an ideal therapy.

261.4: Pilot, open, randomized, multicenter trial for the comparison of hypothermic versus normothermic ex-situ liver preservation in DCD liver transplantation with extended ischemia time (DCDNet trial).

261.4: Pilot, open, randomized, multicenter trial for the comparison of hypothermic versus normothermic ex-situ liver preservation in DCD liver transplantation with extended ischemia time (DCDNet trial).

The evolution of tumor enucleation partial nephrectomy: A comparison of perioperative outcomes for sutureless hemostatic bandage as an alternative to standard renorrhaphy.

The standard approach to hemostasis during partial nephrectomy (PN) is to perform suture renorrhaphy (SR). Application of a hemostatic bandage (HB) is an alternative to minimize blood loss and devitalized renal parenchyma. We aim to evaluate perioperative outcomes of PN with tumor enucleation (TE) comparing SR to HB. We analyzed a retrospective cohort of 195 patients undergoing robot-assisted laparoscopic PN with TE performed at a tertiary referral center (2012-2022). Hemostasis was obtained with SR in 54 patients while 141 patients underwent application of HB consisting of Surgicel®, Gelfoam® soaked in thrombin, and Floseal®. SR patients had tumors of greater complexity by RENAL nephrometry score compared to HB patients (p < 0.001). Operative time (141 vs. 183 min, p < 0.001), warm ischemia time (11.6 vs. 24.2 min, p < 0.001), estimated blood loss (37 vs. 214 mL, p < 0.001), and length of stay (1.2 vs. 1.8 days, p < 0.001) favored HB. There was no significant difference in Clavien-Dindo grade ≥3 complications (p = 0.22). Renal function was comparable with mean estimated glomerular filtration rate decrease of 0.66 and 0.54 mL/min/1.73 m2 at 3 months postoperatively for HB and SR, respectively (p = 0.93). Application of an HB is a safe alternative to SR for hemostasis following PN with TE in appropriately selected patients.

448.3: Benefit of hypothermic perfusion on kidney graft survival while adding cold ischemia time.

448.3: Benefit of hypothermic perfusion on kidney graft survival while adding cold ischemia time.

P.308: Insulating effect of thermal barrier bag (OrganPocket ®) on second warm ischemic time during living renal transplantation: Comparison with direct cooling cases.

P.308: Insulating effect of thermal barrier bag (OrganPocket ®) on second warm ischemic time during living renal transplantation: Comparison with direct cooling cases.

The Mayo Adhesive Probability Score as a Predictor of Postoperative Renal Function in Robot-assisted Partial Nephrectomy.

The aim of this study was to evaluate the Mayo Adhesive Probability (MAP) score as a predictor of split renal function deterioration after robot-assisted partial nephrectomy (RAPN). A total of 30 patients who underwent RAPN were identified retrospectively. The parameters evaluated included patient characteristics, tumor diameter, MAP score, warm ischemic time (WIT), and renal function. Split renal function was evaluated using Tc-99m DTPA renal scintigraphy before and six months after surgery. Univariate and multivariate logistic regression analyses were performed. Nine patients (30.0%) showed more than 90% preservation of split renal function on the operated side. The MAP score (p=0.015), cT1b tumor (p=0.0002), and WIT (p=0.044) were associated with preservation of split renal function six months after surgery on univariate analysis. The MAP score was the strongest predictor of preservation of split renal function six months after surgery on multivariable analysis (p=0.007). On receiver-operating characteristic (ROC) curve analysis, the MAP score (cutoff value 3.0; p=0.01) was a significant predictor of split renal function six months after surgery. The MAP score was significantly associated with postoperative split renal function six months after RAPN on the operated kidney side. The MAP score is useful for predicting split renal function after RAPN.

Association Between Patient and System Delays and In-Hospital Mortality in Primary PCI for STEMI: Findings from a Large, Nationwide Inpatients Sample

PurposeSystem delay is associated with mortality in patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). However, the influence of patient delay has been relatively overlooked. We aimed to evaluate the influence of patient and system delays on STEMI patients undergoing primary PCI in China. MethodsSTEMI patients registered at the Nationwide Chinese Cardiovascular Association Database-Chest Pain Center from January 2017 to September 2021 were screened. The exposures were total ischemic time (TIT), system delay and patient delay. The primary outcome was in-hospital mortality. ResultsAmong 458,260 patients from 2529 centers, median TIT, system delay and patient delay were 4.1, 1.5 and 2.1 hours, respectively. The adjusted odds ratio of in-hospital mortality increased by 2.2% (odds ratio [OR], 1.022, 95% confidence interval [CI], 1.017-1.027), 2.3% (1.023, 1.006-1.040) and 2.2% (1.022, 1.017-1.027) for every one-hour increase in TIT, system delay and patient delay, respectively. ConclusionsPatient delay demonstrated a comparable impact to system delay on in-hospital mortality among STEMI patients undergoing primary PCI. Widespread primary PCI-capable center, improved awareness about myocardial infarction and regional transfer system are essential to shorten patient delay.

Mechanical circulatory support early after pediatric heart transplantation—an analysis from the Pediatric Heart Transplant Society

BackgroundThe use of early Mechanical Circulatory Support (MCS) following pediatric heart transplantation is not well-published. This paper attempts to uncover the incidence, predisposing factors and outcomes of MCS in a large, international cohort. MethodsThe Pediatric Heart Transplant Society Database (an international, prospective, event-driven database) was retrospectively analyzed for all cases of primary heart transplant over an 11-year period (2010-2020), dividing the cohort based on need for MCS within 30 days of transplantation. ResultsOf 4321 primary transplants, 249 (5.8%) required MCS (230 ECMO, 19 VAD). In a Cox proportional hazard model, congenital heart disease (p = 0.0002), older donor age (p < 0.0001), and longer ischemic time (p = 0.018) were each related to an increased need for MCS; increasing recipient body surface area (p < 0.0001) and increasing donor left ventricular ejection fraction (p = 0.016) were both correlated with less MCS use. 1-year survival in those requiring MCS was 54.2%, compared with 94.8% in those who did not need MCS (p < 0.0001). Later survival in patients surviving to one year was similar between the groups. ConclusionsMCS is used infrequently following pediatric heart transplant, and is related to donor, recipient and transplant factors. Although mortality is high, those surviving the first year post-transplant have excellent outcomes. Judicious use in those patients who would otherwise perish is therefore justified.

Risk and Reward: Nationwide Analysis of Cardiac Transplant Center Variation in Organ Travel Distance and the Effects on Outcomes.

The 2018 UNOS allocation policy change deprioritized geographic boundaries to organ distribution, and the effects of this change have been widespread. The aim of this investigation was to analyze changes in donor transplant center distance for organ travel and corresponding outcomes before and after the allocation policy change. The UNOS database was utilized to identify all adult patients waitlisted for heart transplants from 2016 to 2021. Transplant centers were grouped by average donor heart travel distance based on whether they received more or less than 50% of organs from >250 miles away. Descriptive statistics were provided for waitlisted and transplanted patients. Regression analyses modeled waitlist mortality, incidence of transplant, overall survival, and graft survival. Centers with a longer average travel distance had a higher mean annual transplant volume with a reduction in total days on a waitlist (86.6 vs. 149.2 days), an increased cold ischemic time (3.6 vs. 3.2 h), with no significant difference in post-transplant overall survival or graft survival. The benefits of reducing waitlist time while preserving post-transplant outcomes extend broadly. The trends observed in this investigation will be useful as we revise organ transplant policy in the era of new organ procurement and preservation techniques.

Outcome-Orientated Organ Allocation-A Composite Risk Model for Pancreas Graft Evaluation and Acceptance.

Background: Pancreas transplantation (PTX) remains the most effective treatment to prevent long-term complications and provide consistent euglycemia in patients with endocrine pancreatic insufficiency, mainly in type I diabetic patients. Considering early graft loss (EGL) and the perioperative complication rate, an optimal risk stratification based on donor risk factors is paramount. Methods: In our single-center study, we retrospectively assessed the risk factors for EGL and reduced graft survival in 97 PTXs (82 simultaneous pancreas and kidney [SPK], 11 pancreases transplanted after kidney [PAK] and 4 pancreases transplanted alone [PTA]) between 2010 and 2021. By statistically analyzing the incorporation of different donor risk factors using the Kaplan-Meier method and a log-rank test, we introduced a composite risk model for the evaluation of offered pancreas grafts. Results: The overall EGL rate was 6.5%. In the univariate analysis of donor characteristics, age > 45 years, BMI > 25 kg/m2, lipase > 60 U/L, cerebrovascular accident (CVA) as the cause of death, mechanical cardiopulmonary resuscitation (mCPR), cold ischemia time (CIT) > 600 min and retrieval by another center were identified as potential risk factors; however, they lacked statistical significance. In a multivariate model, age > 45 years (HR 2.05, p = 0.355), BMI > 25 kg/m2 (HR 3.18, p = 0.051), lipase > 60 U/L (HR 2.32, p = 0.148), mCPR (HR 8.62, p < 0.0001) and CIT > 600 min (HR 1.89, p = 0.142) had the greatest impact on pancreas graft survival. We subsumed these factors in a composite risk model. The combination of three risk factors increased the rate of EGL significantly (p = 0.003). Comparing the pancreas graft survival curves for ≥3 risk factors to <3 risk factors in a Kaplan-Meier model revealed significant inferiority in the pancreas graft survival rate (p = 0.029). Conclusions: When evaluating a potential donor organ, grafts with a combination of three or more risk factors should only be accepted after careful consideration to reduce the risk of EGL and to significantly improve outcomes after PTX.

Risk factors and prognostic modeling in bridging extracorporeal membrane oxygenation patients before lung transplantation.

The increased use of preoperative extracorporeal membrane oxygenation (ECMO) as a life support system before lung transplantation demands a better understanding of the associated prognostic factors. This study aims to discern the critical factors influencing the survival outcomes of ECMO patients and design a prognostic model tailored to this patient group. We retrospectively gathered and analyzed baseline and clinical data of patients who underwent preoperative bridging ECMO before lung transplantation from the United Network for Organ Sharing (UNOS) database. Univariate and multivariate Cox regression analyses were conducted and a prognostic model was generated to identify the independent factors influencing survival outcomes in these patients. The predictive model was cross-validated using the k-fold method where k=5. Our study included 1,202 patients. Both single and multiple analyses showed that age over 51 years, high body mass index (BMI), a history of dialysis before transplantation, donor hypertension, prolonged cold ischemia time, and high serum total bilirubin are adverse prognostic factors for the survival of ECMO-bridged lung transplant patients. Using the multivariate analysis, we created a prognosis model and a nomogram to predict 1-year post-transplant survival, with a receiver operating characteristic (ROC) curve area of 0.760 in internal validation. The 1-year survival rate calibration curve supported the nomogram's accuracy. This study involved the development of a survival prognosis model for patients undergoing lung transplantation with preoperative ECMO bridging, which was validated through extensive data analysis. The prognosis model exhibited high accuracy and predictive capability, effectively predicting the survival outcomes of patients both pre- and post-surgery.

Contrasting predictors of severe primary graft dysfunction following transplant for chronic and acute respiratory failure.

Lung transplantation represents a pivotal intervention for individuals grappling with end-stage lung diseases, and the role of lung transplantation in acute respiratory distress syndrome (ARDS) patients has garnered increased attention especially after the coronavirus disease 2019 (COVID-19) pandemic. Multiple studies have demonstrated a high incidence of primary graft dysfunction (PGD) in patients with ARDS compared to contemporaneous controls undergoing transplantation for chronic end-stage lung diseases although underlying mechanisms or risk factors remain unknown. This retrospective study investigates the contrasting risk factors for PGD grade 3 in patients with ARDS and chronic respiratory failure undergoing lung transplantation. The study included 293 patients who underwent lung transplantation from January 2018 through June 2023. We performed a multivariate logistic regression analysis using variables from the univariate logistic regression analyses to predict PGD grade 3. Our findings reveal distinct predictors for PGD grade 3 in the two cohorts. ARDS patients had higher incidence of PGD grade 3 than non-ARDS patients (30.2% vs. 9.6%, P<0.001). Multivariate logistic regression analysis showed ischemic time [odds ratio (OR) =0.60; 95% confidence interval (CI): 0.40-0.90; P=0.01] as predictor of PGD grade 3 for non-ARDS patients, and age (OR =0.72; 95% CI: 0.52-0.99; P=0.048), pre-operative albumin (OR <0.01; 95% CI: <0.01-0.74; P=0.042) for ARDS patients. Interestingly, there was no notable difference in post-transplant survival between the two groups. This study highlights differing risk profiles for severe PGD in ARDS and non-ARDS lung transplant recipients, underscoring the need for tailored approaches in managing these patients. It paves the way for further research to refine strategies aimed at reducing PGD incidence and enhancing transplant outcomes in these distinct populations.

Determinants of Long Waiting Time to Kidney Transplantation

BackgroundDisparity in waiting time to kidney transplantation led to new policy (KAS250). Our aims were to identify variables associated with long wait time (LWT); assess the impact of KAS250 on WT; and analyze modifiable transplant center behaviors correlated with WT. MethodsSRTR data for adult deceased donor kidney transplants were analyzed. Time-periods from 8/1/2018-7/31/2019 and 5/1/2021-4/30/2022 were chosen for pre- and post-KAS250 analyses. Transplant centers were categorized as LWT or SWT centers depending on whether pre-KAS250 median center waiting times were greater or less than the national pre-KAS250 median waiting time of 57.8 months. ResultsIn multivariate analysis, transplantation with HCV NAT negative kidneys was associated with an additional 21.3 months of WT (CI: 18.5-24.2, P < .0001), and transplantation with KDPI <85% kidneys was associated with an additional 10.8 months (CI: 8.2-13.3, P < .0001). Post-KAS250 national kidney transplant waiting time decreased from 61-58 months (P < .0001) and waiting time at LWT centers decreased from 74-69 months (P < .0001). Cold ischemic times (CIT) increased (20.2 hours vs 18.3 hours, P < .0001) and DGF rates also increased (32.7% vs 31.0%, P < .0001). Centers generally displayed more aggressive transplantation practices post-KAS250 however significant differences in DCD utilization, organ offer acceptance ratios and tolerance for long CIT persist between SWT and LWT centers. ConclusionKAS250 has reduced waiting time disparities between SWT and LWT centers at the cost of increased CIT and DGF and reduced allocation efficiency. Significant differences in transplant practice persist between SWT and LWT centers.