Novel indications for referral and care for simultaneous liver kidney transplant recipients.

PURPOSE OF REVIEW: Kidney dysfunction is challenging in liver transplant candidates to determine whether it is reversible or not. This review focuses on the pertinent data on how to best approach liver transplant candidates with kidney dysfunction in the current era after implementing the simultaneous liver kidney (SLK) allocation policy and safety net. RECENT FINDINGS: The implementation of the SLK policy inverted the steady rise in SLK transplants and improved the utilization of high-quality kidneys. Access to kidney transplantation following liver transplant alone (LTA) increased with favorable outcomes. Estimating GFR in liver transplant candidates remains challenging, and innovative methods are needed. SLK provided superior patient and graft survival compared to LTA only for patients with advanced CKD and dialysis at least 3 months. SLK can provide immunological protection against kidney rejection in highly sensitized candidates. Post-SLK transplant care is complex, with an increased risk of complications and hospitalization. SUMMARY: The SLK policy improved kidney access and utilization. Transplant centers are encouraged, under the safety net, to reserve SLK for liver transplant candidates with advanced CKD or dialysis at least 3 months while allowing lower thresholds for highly sensitized patients. Herein, we propose a practical approach to liver transplant candidates with kidney dysfunction.

A paradigm shift from office to home-based blood pressure measurement approaches in kidney transplant recipients.

PURPOSE OF REVIEW: The unattended blood pressure (BP) readings from home blood pressure (HBP) monitoring should provide more accurate BP readings than attended BP obtained from office blood pressure (OBP). Here, we review evidence supporting the clinical utility of HBP and automatic remote monitoring of blood pressure (ARM-BP) in kidney transplant recipients (KTR). RECENT FINDINGS: BP from 24-h ambulatory blood pressure monitoring (24-h ABPM) is higher than but better associated with kidney and cardiovascular outcomes compared to OBP and HBP. While there is discordance of BP readings across different BP measurement methods causing BP misclassification, HBP provides BP readings closer to the readings from the 24-h ABPM than those from OBP. Systolic and diastolic BP is better controlled within 30 days after utilizing ARM-BP. SUMMARY: Compared to OBP, HBP minimizes the attended effect of OBP, and its readings are closer to the gold standard 24-h ABPM. ARM-BP improves BP control in the short term and trials of longer follow-up duration are required to evaluate sustained clinical benefits in KTR. The paradigm of BP monitoring may shift toward HBP, while OBP may be utilized primarily for KTR who cannot perform HBP for hypertension diagnosis and management.

Changing landscape of living kidney donation and the role of telemedicine.

PURPOSE OF REVIEW: There has been a decline in living kidney donation over the last two decades. Donors from low-income families or racial/ethnic minorities face greater disproportionate geographic, financial, and logistical barriers to completing lengthy and complex evaluations. This has contributed to the decreased proportion of these subgroups. The authors view telemedicine as a potential solution to this problem. RECENT FINDINGS: Since the initial decline of donors in 2005, biologically related donors have experienced a lack of growth across race/ethnicity. Conversely, unrelated donors have emerged as the majority of donors in recent years across race/ethnicity, except for unrelated black donors. Disparities in access to living kidney donation persist. Telemedicine using live-video visits can overcome barriers to access transplant centers and facilitate care coordination. In a U.S. survey, nephrologists, surgeons, coordinators, social workers, and psychologists/psychologists across transplant centers are favorably disposed to use telemedicine for donor evaluation/follow-up beyond the coronavirus disease 2019 pandemic. However, with the waning of relaxed telemedicine regulations under the Public Health Emergency, providers perceive payor policy and out-of-state licensing as major factors hindering telemedicine growth prospects. SUMMARY: Permanent federal and state policies that support telemedicine services for living kidney donation can enhance access to transplant centers and help overcome barriers to donor evaluation.

Novel therapeutic approaches for COVID-19 in chronic kidney disease and transplant.

PURPOSE OF REVIEW: Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is the novel virus responsible for the current worldwide pandemic. The scientific and healthcare communities have made every effort to discover and implement treatment options at a historic pace. Patients with kidney disease are uniquely vulnerable to an infectious pandemic because of their need to be in frequent contact with the healthcare system for life-sustaining renal replacement therapy whether it be by dialysis or transplant. RECENT FINDINGS: The use of targeted viral therapies, extracorporeal therapies, immunosuppressive therapy and public health interventions are important in the management of patients with COVID-19 but require special consideration in patients with kidney disease because of the complexity of their condition. SUMMARY: Here, we discuss some of the major efforts made to prevent spread and emerging treatment options for this virus, as they pertain to patients with kidney disease.

Novel options for failing allograft in kidney transplanted patients to avoid or defer dialysis therapy.

PURPOSE OF REVIEW: Despite improvement in short-term renal allograft survival in recent years, renal transplant recipients (RTR) have poorer long-term allograft outcomes. Allograft function slowly declines with periods of stable function similar to natural progression of chronic kidney disease in nontransplant population. Nearly all RTR transitions to failing renal allograft (FRG) period and require transition to dialysis. Conservative chronic kidney disease management before transition to end-stage renal disease is an increasingly important topic; however, there is limited data in RTR regarding how to delay dialysis initiation with conservative management. RECENT FINDINGS: Since immunological and nonimmunological factors unique to RTR contribute to decline in allograft function, therapies to slow progression of FRG should take both sets of factors into account. Renal replacement therapy either incremental dialysis or rekidney transplantation should be explored. This required taking benefits and risks of continuing immunosuppressive medications into account when allograft nephrectomy may be necessary. SUMMARY: FRG may benefit from various interventions to slow progression of worsening allograft function. Until there are stronger evidence to guide interventions to preserve renal function, extrapolating evidence from nontransplant patients and clinical judgment are necessary. The goal is to provide individualized care for conservative management of RTR with FRG.

A Case of Novel Coronavirus Disease 19 in a Chronic Hemodialysis Patient Presenting with Gastroenteritis and Developing Severe Pulmonary Disease.

Novel coronavirus disease 2019 (COVID-19) is a highly infectious, rapidly spreading viral disease with an alarming case fatality rate up to 5%. The risk factors for severe presentations are concentrated in patients with chronic kidney disease, particularly patients with end-stage renal disease (ESRD) who are dialysis dependent. We report the first US case of a 56-year-old nondiabetic male with ESRD secondary to IgA nephropathy undergoing thrice-weekly maintenance hemodialysis for 3 years, who developed COVID-19 infection. He has hypertension controlled with angiotensin receptor blocker losartan 100 mg/day and coronary artery disease status-post stent placement. During the first 5 days of his febrile disease, he presented to an urgent care, 3 emergency rooms, 1 cardiology clinic, and 2 dialysis centers in California and Utah. During this interval, he reported nausea, vomiting, diarrhea, and low-grade fevers but was not suspected of COVID-19 infection until he developed respiratory symptoms and was admitted to the hospital. Imaging studies upon admission were consistent with bilateral interstitial pneumonia. He was placed in droplet-eye precautions while awaiting COVID-19 test results. Within the first 24 h, he deteriorated quickly and developed acute respiratory distress syndrome (ARDS), requiring intubation and increasing respiratory support. Losartan was withheld due to hypotension and septic shock. COVID-19 was reported positive on hospital day 3. He remained in critical condition being treated with hydroxychloroquine and tocilizumab in addition to the standard medical management for septic shock and ARDS. Our case is unique in its atypical initial presentation and highlights the importance of early testing.

Association of age with risk of first and subsequent allograft failure and mortality among young kidney transplant recipients in the USA - a retrospective cohort study.

Adolescent age may be a high-risk period for kidney allograft failure. However, the knowledge on this topic is limited mostly to the first transplant. Among 20 960 patients aged ≤21 years at the first kidney transplantation from the US Renal Data System, we evaluated the association of age at the first kidney transplant with risk for the first and subsequent graft failures (1st, 2nd, and 3rd) using the conditional risk set model for recurrent time-to-event data. The median age was 15 (interquartile range: 9-18) years, and 18% received transplants twice or more during a median follow-up of 9.7 years. The risk for graft failures was highest in 16 to <18 years old with an adjusted hazard ratio (aHR) of 1.93 (95% CI, 1.73-2.15; reference: <3 years). When separately analyzed, the highest risk was observed in 17, 19, and 21 years old for the first, second, and third transplant, respectively. Those 16 to <18 years were also strongly associated with the highest risk for death after returning to dialysis (aHR, 4.01; 95% CI, 2.82-5.71). Adolescent recipients remain at high risk for allograft failure for a long time, which may result in high mortality risk, even though they surpass this high-risk period soon after the first transplant.

Hyponatremia: A possible immuno-neuroendocrine interface with COVID-19 in a kidney transplant recipient.

There is fast-emerging, cumulative clinical data on coronavirus disease 2019 (COVID-19) in kidney transplant recipients. Although respiratory tract symptoms are often the initial presentation among kidney transplant recipients who contract COVID-19, other clinical features which may indicate underlying SARS-CoV-2-related inflammation, such as gastrointestinal symptoms, are not uncommon. Hyponatremia can develop and may reflect underlying inflammation. Interferon-6 is an important pro-inflammatory cytokine involved in the pathogenesis of severe COVID-19 complications and may play a role in the inappropriately higher secretion of antidiuretic hormone leading to hyponatremia. This pathway is the so-called immuno-neuroendocrine interface. Hyponatremia in COVID-19 has been reported in a few case series of non-kidney transplant patients and only one reported kidney transplant recipient. However, the clinical course and prognostic value of hyponatremia in this population are not described in detail. We report a kidney transplant recipient who was infected with COVID-19 and exhibited severe hyponatremia secondary to the syndrome of inappropriate antidiuretic hormone secretion. Hyponatremia is one of the clinical presentations of COVID-19, although less common, and may occur more frequently in kidney transplant recipients. Thus, the possible underlying immuno-neuroendocrine relationship related to the inflammatory process of COVID-19 leading to hyponatremia and its prognostic value are reviewed.

Utilization of Carbon Dioxide Angiography and Percutaneous Balloon Angioplasty for Treatment of Transplant Renal Artery Stenosis.

BACKGROUND: Transplant renal artery stenosis (TRAS) may lead to graft dysfunction and failure. Progressive deterioration of renal allograft function may be exacerbated by contrast-induced nephrotoxicity during iodine contrast administration for renovascular imaging of allografts. We present our institutional experience of endovascular management for TRAS using CO2 digital subtraction angiography (CO2-DSA) and balloon angioplasty to manage failing renal transplants. METHODS: Four patients with renal allografts from March 2017-May 2018 were referred for graft dysfunction and pending renal transplant failure. Indications for referral included refractory hypertension, decreasing renal functioning, and elevated renovascular systolic velocities. RESULTS: Median age of the four patients was 41.5 years (22-60 years). There were two male and female patients. Chronic hypertension and type 2 diabetes mellitus were the most common comorbidities. An average total of 75 mL of CO2 was used, supplemented with 17.4 mL of iodinated contrast. All patients had improvements in renal function following intervention with a mean decrease in systolic and diastolic blood pressure of 25.8% and 21.4%, respectively. We also observed a mean decrease of BUN by 13.6% and creatinine by 37.4%. Additionally, eGFR increased by 37.7%. All allografts survived after surgery, and only one patient required repeat angioplasty for recurrence. CONCLUSIONS: CO2-DSA with balloon angioplasty can be successfully utilized to salvage deteriorating kidney allograft function in patients with TRAS.

Association of Citizenship Status With Kidney Transplantation in Medicaid Patients.

BACKGROUND: Although individuals classified as nonresident aliens, including undocumented immigrants, are entitled to receive emergency dialysis in the United States regardless of their ability to pay, most states do not provide them with subsidized care for maintenance dialysis or kidney transplantation. We explored whether nonresident aliens have similar outcomes to US citizens after receiving kidney transplants covered by Medicaid, a joint federal and state health insurance program. STUDY DESIGN: Retrospective observational cohort study. SETTING & PARTICIPANTS: All adult Medicaid patients in the US Renal Data System who received their first kidney transplant from 1990 to 2011. PREDICTOR: Citizenship status, categorized as US citizen, nonresident alien, or permanent resident. OUTCOME: All-cause transplant loss. MEASUREMENTS: HRs and 95% CIs estimated by applying Cox proportional hazards frailty models with transplantation center as a random effect. RESULTS: Of 10,495 patients, 8,660 (82%) were US citizens, 1,489 (14%) were permanent residents, and 346 (3%) were nonresident aliens, whom we assumed were undocumented immigrants. Nonresident aliens were younger, healthier, receiving dialysis longer, and more likely to have had a living donor. 71% underwent transplantation in California, and 61% underwent transplantation after 2005. Nonresident aliens had a lower unadjusted risk for transplant loss compared with US citizens (HR, 0.48; 95% CI, 0.35-0.65). Results were attenuated but still significant when adjusted for demographics, comorbid conditions, dialysis, and transplant-related factors (HR, 0.67; 95% CI, 0.46-0.94). LIMITATIONS: Citizenship status was self-reported, possible residual confounding. CONCLUSIONS: Our study suggests that the select group of insured nonresident aliens who undergo transplantation with Medicaid do just as well as US citizens with Medicaid. Policymakers should consider expanding coverage for kidney transplantation in nonresident aliens, including undocumented immigrants, given the associated high-quality outcomes in these patients.

There's no place like home: 35-year patient survival on home hemodialysis.

The vast majority of maintenance dialysis patients suffer from poor long-term survival rates and lower levels of health-related quality of life. However, home hemodialysis is a historically significant dialysis modality that has been associated with favorable outcomes as well as greater patient autonomy and control, yet only represents a small minority of the total dialysis performed in the United States. Some potential disadvantages of home hemodialysis include vascular access complications, infection-related hospitalizations, patient fatigue, and attrition. In addition, current barriers and challenges in expanding the utilization of this modality include limited patient and provider education and technical expertise. Here we report a 65-year old male with end-stage renal disease due to Alport's syndrome who has undergone 35 years of uninterrupted thrice-weekly home hemodialysis (ie, every Sunday, Tuesday, and Thursday evening, each session lasting 3 to 3» hours in length) using a conventional hemodialysis machine who has maintained a high functional status allowing him to work 6-8 hours per day. The patient has been able to liberalize his dietary and fluid intake while only requiring 3-4 liters of ultrafiltration per treatment, despite having absence of residual kidney function. Through this case of extraordinary longevity and outcomes after 35 years of dialysis and a review of the literature, we illustrate the history of home hemodialysis, its significant clinical and psychosocial advantages, as well as the barriers that hinder its widespread adaptation.

Seasonal variations in transition, mortality and kidney transplantation among patients with end-stage renal disease in the USA.

BACKGROUND: Seasonal variations may exist in transitioning to dialysis, kidney transplantation and related outcomes among end-stage renal disease (ESRD) patients. Elucidating these variations may have major clinical and healthcare policy implications for better resource allocation across seasons. METHODS: Using the United States Renal Data System database from 1 January 2000 to 31 December 2013, we calculated monthly counts of transitioning to dialysis or first transplantation and deaths. Crude monthly transition fraction was defined as the number of new ESRD patients divided by all ESRD patients on the first day of each month. Similar fractions were calculated for all-cause and cause-specific mortality and transplantation. RESULTS: The increasing trend of the annual transition to ESRD plateaued during 2009-2012 (n = 126 264), and dropped drastically in 2013 (n = 117 372). Independent of secular trends, monthly transition to ESRD was lowest in July (1.65%) and highest in January (1.97%) of each year. All-cause, cardiovascular and infectious mortalities were lowest in July or August (1.32, 0.58 and 0.15%, respectively) and highest in January (1.56, 0.71 and 0.19%, respectively). Kidney transplantation was highest in June (0.33%), and this peak was mainly attributed to living kidney transplantation in summer months. Transplant failure showed a similar seasonal variation to naïve transition, peaking in January (0.65%) and nadiring in September (0.56%). CONCLUSIONS: Transitioning to ESRD and adverse events among ESRD people were more frequent in winter and less frequent in summer, whereas kidney transplantation showed the reverse trend. The potential causes and implications of these consistent seasonal variations warrant more investigation.

Incremental Hemodialysis: The University of California Irvine Experience.

Incremental hemodialysis has been examined as a viable hemodialysis regimen for selected end-stage renal disease (ESRD) patients. Preservation of residual kidney function (RKF) has been the driving impetus for this approach given its benefits upon the survival and quality of life of dialysis patients. While clinical practice guidelines recommend an incremental start of dialysis in peritoneal dialysis patients with substantial RKF, there remains little guidance with respect to incremental hemodialysis as an initial renal replacement therapy regimen. Indeed, several large population-based studies suggest that incremental twice-weekly vs. conventional thrice-weekly hemodialysis has favorable impact upon RKF trajectory and survival among patients with adequate renal urea clearance and/or urine output. In this report, we describe a case series of 13 ambulatory incident ESRD patients enrolled in a university-based center's Incremental Hemodialysis Program over the period of January 2015 to August 2016 and followed through December 2016. Among five patients who maintained a twice-weekly hemodialysis schedule vs. eight patients who transitioned to thrice-weekly hemodialysis, we describe and compare patients' longitudinal case-mix, laboratory, and dialysis treatment characteristics over time. The University of California Irvine Experience is the first systemically examined twice-weekly hemodialysis practice in North America. While future studies are needed to refine the optimal approaches and the ideal patient population for implementation of incremental hemodialysis, our case-series serves as a first report of this innovative management strategy among incident ESRD patients with substantial RKF, and a template for implementation of this regimen.

Racial-ethnic disparities in mortality and kidney transplant outcomes among pediatric dialysis patients.

BACKGROUND: Previous studies in adult hemodialysis patients have shown that African-American and Hispanic patients have a lower risk of mortality in addition to a lower likelihood of kidney transplantation. However, studies of the association between race and outcomes in pediatric dialysis are sparse and often do not examine outcomes in Hispanic children. The objective was to determine if racial-ethnic disparities in mortality and kidney transplantation outcomes exist in pediatric dialysis patients. METHODS: This was a retrospective cohort analysis of 2,697 pediatric dialysis patients (aged 0-20 years) from a large national dialysis organization (entry period 2001-2011) of non-Hispanic white, African-American, and Hispanic race-ethnicity. Associations between race-ethnicity with mortality and kidney transplantation outcomes were examined separately using competing risks methods. Logistic regression analyses were used to examine the association between race-ethnicity, with outcomes within 1 year of dialysis initiation. RESULTS: Of the 2,697 pediatric patients in this cohort, 895 were African-American, 778 were Hispanic, and 1,024 were non-Hispanic white. After adjusting for baseline demographics, competing risk survival analysis revealed that compared with non-Hispanic whites, African-Americans had a 64 % higher mortality risk (hazards ratio [HR] = 1.64; 95 % CI 1.24-2.17), whereas Hispanics had a 31 % lower mortality risk (HR = 0.69; 95 % CI 0.47-1.01) that did not reach statistical significance. African-Americans also had higher odds of 1-year mortality after starting dialysis (odds ratio [OR] = 2.08; 95 % CI 0.95-4.58), whereas both African-Americans and Hispanics had a lower odds of receiving a transplant within 1 year of starting dialysis (OR = 0.28; 95 % CI 0.19-0.41 and OR = 0.43; 95 % CI 0.31-0.59 respectively). CONCLUSION: In contrast to adults, African-American pediatric dialysis patients have worse survival than their non-Hispanic white counterparts, whereas Hispanics have a similar to lower mortality risk. Both African-American and Hispanic pediatric dialysis patients had a lower likelihood of kidney transplantation than non-Hispanic whites, similar to observations in the adult dialysis population.

Outcomes Among Undocumented Immigrant Kidney Transplant Recipients in California.

Importance: There are over 2 million undocumented immigrants (UI) in California, where currently, all individuals regardless of immigration status have access to kidney transplant. There is a medical perception that UI face a higher risk of transplant failure due to language barriers and lack of access to immunosuppressive medication and health care when compared with US residents (UR). Objective: To elucidate the kidney transplant outcomes of UI at an academic medical center in California. Design, Setting, and Participants: A retrospective cohort study was conducted from a single transplant center during an 8-year study period. Patients who received a kidney transplant at the University of California, Irvine, between January 1, 2012, and September 1, 2019, were included in this study. Data were analyzed from October 2020 to August 2021. Exposures: The primary exposure of this study was citizenship status. UI were defined as immigrants residing in the US without permission or legal documentation. Main Outcomes and Measures: The primary end point was all-cause graft loss defined as the return to dialysis, need for a second kidney transplant, or death. The secondary end points of this study were all-cause mortality and rejection. All-cause mortality between the 2 groups was compared using multiple Cox proportional hazard regression analysis. Other transplant outcomes, including all-cause graft loss and acute rejection, were examined by competing risks regressions with mortality and mortality plus graft loss serving as competing risks, respectively. Results: Of all 446 consecutive kidney transplant recipients, the mean (SD) age was 47 (13) years; 261 patients (59%) were male, and 114 (26%) were UI. During a median (IQR) follow-up time of 3.39 (0.04-8.11) years, 6 UI and 48 UR experienced all-cause graft loss. UR had a 192% (hazard ratio, 2.92; 95% CI, 1.21-6.85; P = .01) and 343% (hazard ratio, 4.34; 95% CI, 1.05-18.69; P = .04) significantly increased unadjusted risk for all-cause graft loss and all-cause mortality, respectively. These results became nonsignificant and were mostly attenuated when adjusted for age and ethnicity. Finally, there was no difference in incidence rate of kidney allograft rejection between the 2 groups (UR, 3.5 per 100 person-years vs UI, 2.4 per 100 person-years; rate ratio, 1.45; 95% CI, 0.90-5.05; P = .08). Conclusions and Relevance: This single-center cohort study found that kidney transplant outcomes of UI were not inferior to those of UR. Across the US, however, UI have consistently had unequal access to transplantation. These findings suggest that extending kidney transplants to UI is safe and does not portend worse outcomes. As a result, denying transplant according to immigration status not only results in higher costs but also worse end stage kidney disease outcomes for an already underserved population.

Preservation of Antiviral Immunologic Efficacy Without Alloimmunity After Switch to Belatacept in Calcineurin Inhibitor-Intolerant Patients.

Introduction: Belatacept has shown potential for prevention of rejection after kidney transplantation, given its demonstration of reduced nephrotoxicity in combination with absence of significant incidence of rejection. However, concerns have been raised regarding increased risk of viral infection. Methods: We set out to explore the impact of the switch to belatacept on alloimmune and antiviral immunity through the study of patients switched from calcineurin inhibitor (CNI) to belatacept within 3 months of kidney transplantation compared with a matched cohort of control patients on a CNI-based regimen. Results: After the switch to belatacept, immune phenotyping demonstrated a decrease in naive and an increase in terminally differentiated effector memory (TMRA) T cells, with no significant difference compared with control patients. Donor-specific immune response, measured by intracellular cytokine staining (ICS), did not change significantly either by single or double cytokine secretion, but it was associated with the appearance of donor-specific antibody (DSA) in the control but not the belatacept cohort (P = 0.039 for naive and P = 0.002 for TMRA subtypes). Increased incidence of de novo DSA development was observed in the control group (P = 0.035). Virus-specific immune response, as measured by ICS in response to cytomegalovirus (CMV) or Epstein-Barr virus (EBV), was similar in both groups and stable over time. Conclusion: We found that belatacept use was associated with an absence of alloreactivity without impact on immune phenotype, while preserving the antiviral immune response, for patients switched from a CNI-based regimen. In parallel, the antiviral immune response against CMV and EBV was preserved after the belatacept switch (clinicaltrials.gov: NCT01953120).

Is It Time to Utilize Genetic Testing for Living Kidney Donor Evaluation?

Living donor kidney transplantation is an effective strategy to mitigate the challenges of solid organ shortage. However, being a living kidney donor is not without risk, as donors may encounter short- and long-term complications including the risk of developing chronic kidney disease, end-stage kidney disease, hypertension, and possible pregnancy-related complications. Although the evaluation of potential living donors is a thorough and meticulous process with the intention of decreasing the chance of complications, particularly in donors who have lifetime risk projection, risk factors for kidney disease including genetic predispositions may be missed because they are not routinely investigated. This type of testing may not be offered to patients due to variability and decreased penetrance of symptoms and lack of availability of appropriate genetic testing and genetic specialists. We report a case of a middle-aged woman with a history of gestational diabetes and preeclampsia who underwent an uneventful living kidney donation. She developed postdonation nonnephrotic range proteinuria and microscopic hematuria. Given the risk of biopsy with a solitary kidney, genetic testing was performed and revealed autosomal dominant Alport syndrome. Our case underscores the utility of genetic testing. Hopefully, future research will examine the incorporation of predonation genetic testing into living kidney donor evaluation.

Intraoperative Near-Infrared Spectroscopy Monitoring of Renal Allograft Reperfusion in Kidney Transplant Recipients: A Feasibility and Proof-of-Concept Study.

Conventional renal function markers are unable to measure renal allograft perfusion intraoperatively, leading to delayed recognition of initial allograft function. A handheld near-infrared spectroscopy (NIRS) device that can provide real-time assessment of renal allograft perfusion by quantifying regional tissue oxygen saturation levels (rSO2) was approved by the FDA. This pilot study evaluated the feasibility of intraoperative NIRS monitoring of allograft reperfusion in renal transplant recipients (RTR). Intraoperative renal allograft rSO2 and perfusion rates were measured in living (LDRT, n = 3) and deceased donor RTR (DDRT, n = 4) during the first 50 min post-reperfusion and correlated with renal function markers 30 days post-transplantation. Intraoperative renal allograft rSO2 for the DDRT group remained significantly lower than the LDRT group throughout the 50 min. Reperfusion rates were significantly faster in the LDRT group during the first 5 min post-reperfusion but remained stable thereafter in both groups. Intraoperative rSO2 were similar among the upper pole, renal hilum, and lower pole, and strongly correlated with allograft function and hemodynamic parameters up to 14 days post-transplantation. NIRS successfully detected differences in intraoperative renal allograft rSO2, warranting future studies to evaluate it as an objective method to measure ischemic injury and perfusion for the optimization of preservation/reperfusion protocols and early prediction of allograft function.