MO1003: Role of Tacrolimus Trough Levels on Intra-Abdominal Pressure After Kidney Transplantation

BACKGROUND AND AIMS

Increased intra-abdominal pressure (IAP) is common after kidney transplantation (KT). However, the role of potential transplant-specific predictors of this complication, such as tacrolimus-associated endothelial dysfunction, remains unclear. We aimed to describe the relationship between tacrolimus trough levels and IAP in a sample of incident KT patients.

METHOD

Single-centre prospective cohort of deceased-donor KTs. Anesthesia, surgical technique and immunosuppression induction therapy were the same in all cases. IAP monitoring was performed according to WSACS guidelines using the urinary bladder technique (UnoMeter Abdo-Pressure kit). IAP values were registered every 8h during the first 72 h after surgery or until reoperation. Mean IAP values during the first 7 2h (72 h-IAP) were used in this analysis. The first measured tacrolimus trough levels after transplantation were included as a potential predictor of IAP. Patients without recorded tacrolimus trough levels during the first 7 days after surgery were excluded. The study was approved by the local ethics committee.

RESULTS

A total of 192 patients were enrolled in the study. Table 1A summarizes relevant patient and haemodynamic variables. Subjects with more severe intra-abdominal hypertension were more commonly males, with longer dialysis vintage, higher BMI and suffered diabetes more frequently. Multivariate linear regression analysis was used to examine potential predictors of 72 h-IAP, including male sex, months on dialysis, body mass index (BMI) (Table 1B), 72 h-fluid balance and tacrolimus trough levels. Recipient age, months on dialysis, BMI and tacrolimus trough levels were independent predictors of 72 h-IAP.

CONCLUSION

Tacrolimus-associated endothelial dysfunction may play a role in the increase of IAP after transplantation. In contrast, accumulated fluid balance, one of the strongest predictors of IAP in the ICU setting, failed to predict IAP values in our sample. These results offer new insight both into the pathophysiology of increased IAP and into the complex mechanisms of tacrolimus-associated nephrotoxicity in the early post-transplant period.

MO335: Reaching SCR 4.0 mg/dL, the Magical Number for KDIGO-2012 AKI Stage 3. Is it Adequate for Stratifying Severity of Acute on Chronic Kidney Disease?

BACKGROUND AND AIMS

Reaching a SCr ≥ 4 is one criterion of classification for stage 3 in the KDIGO-2012 AKI guidelines. No previous study has challenged this arbitrary cut point by comparing its performance on how patients with pure AKI (pAKI) versus acute on chronic kidney disease (AoCKD) reach that ‘magical number’, and how it affects the prognosis.

METHOD

Retrospective study of patients with AKI, classified according to the KDIGO-2012 guidelines. We analysed a sub-group of patients that reached a maximum SCr ≥ 4 and divided them in pAKI (basal eGFR ≥ 60) and AoCKD (≥15–≤59). We evaluated epidemiological and clinical variables, and compared the clinical outcomes needed for HD, in-hospital mortality and HD dependence at discharge. As 21 (6%) of AoCKD individuals already had a basal SCr ≥ 4.0, they were excluded in the analysis.

RESULTS

A total of 492 individuals met the inclusion criteria: 341 (69%) in the AoCKD group. Individuals in this group were older and had a higher Charlson's index. Table 1A summarizes the comparison of clinical characteristics, all patients in the pAKI group reached a four SCr with a rate of SCr increments ≥ 3×. We found no statistically significant difference in in-hospital mortality and the need for HD. The AoCKD group was more dependent on HD at discharge (Table 1B). Figure 1 shows the rate of SCr increments by which individuals reached > 4.0 mg/dL.

CONCLUSION

We found that individuals in the AoCKD group differ in their basal characteristics from the pAKI group and need lesser increments in SCr to reach the magical number of 4.0 mg/dL to be classified in stage 3. May be, one size does not fit all, and individuals with prior CKD may benefit from a lower rate of SCr increase to stratify AKI severity. We consider that a pitfall in this staging criterion consists in the small portion of patients in the AoCKD group that have a basal SCr ≥ 4.0, with a skew to AKI-KDIGO stage 3.

MO442: COVID-19 Disease Severity and Risk of 12-Month CKD Progression

BACKGROUND AND AIMS

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been in our daily practice for almost 2 years now. Since the beginning of the pandemic, we have aimed to study its most immediate effects on patients to find the best line of treatment or, at least, mitigate its worst outcomes. Nevertheless, we also know some long-term health consequences such as fatigue, sleep difficulties, headache, among others, but its long-term kidney effects are not entirely clear yet. The aim of this study was to describe if coronavirus disease's (COVID-19) severity increases the risk of chronic kidney disease (CKD) progression after a previous hospitalization and observe if there are any additional risk factors that could help us predict this outcome.

METHOD

In this study, a sample of consecutive patients who required admission due to COVID-19 during the first wave of the pandemic (from March to May of 2020) was recruited. Patients were followed for 12 months since initial admission. The composite outcome of the study included either death or CKD progression. CKD progression was defined as incremental progression to a higher KDIGO CKD stage compared to baseline pre COVID-19 renal function [(in mL/min/1.73 m2): estimated glomerular filtration rate (eGFR) ≥60; stage 3a: 45–59; stage 3b: 30–44; stage 4: 15–29; stage 5: <15], or dialysis initiation. Cardiovascular disease was defined as a history of myocardial infarction, stroke, or peripheral vascular disease. Chronic lung diseases included asthma, chronic obstructive pulmonary disease and chronic bronchitis.

RESULTS

The sample was composed of 93 patients, of which 14 (15.1%) died during follow-up. Of those alive 12 months after initial admission, 17 (21.5%) suffered CKD progression. No patient required renal replacement therapy. Patients that suffered the composite outcome presented a higher prevalence of cancer, tended to be slightly older and suffered from additional comorbidities more frequently (Table). In multivariate logistic regression analysis, previous history of CKD [odds ratio (OR): 1.066 (0.433–2.624); P = 0.889], severe or critical COVID-19 on admission [OR: 0.657 (0.24–1.8); P =0.414] or ICU admission [OR: 0.986 (0.082–11.898); P = 0.991] failed to predict the composite outcome.

CONCLUSION

Our main hypothesis was that COVID-19 sequelae should be due to an exaggerated activation of the immune system against the virus. Thus, patients that suffered severe COVID-19 should be expected to develop more long-term health consequences of the infection when compared with those with milder disease. However, we failed to prove any link between COVID-19 severity and long-term CKD progression. History of CKD or ICU admission was also unable to predict the composite outcome.

Previous studies have described a relationship between COVID-19 severity and adverse renal outcomes, a relationship that we failed to observe. These discrepancies could be due to the small sample size of our study and the different definition of CKD progression applied. In addition, age could act as a potential modifier of CKD progression after admission due to COVID. More studies are required to further clarify the mechanisms and long-term renal consequences of COVID-19 and define potential lines of treatment.

MO334: Incidence of AKI Among Hospitalized COVID-19 Patients During the First and Sixth Waves of the Pandemic

BACKGROUND AND AIMS

During the last 2 years, we have witnessed several waves of the COVID-19 pandemic characterized by massive infections among the general population, sudden increases in the number of hospitalizations and variable rates of complications and mortality among patients.

Acute kidney injury (AKI) has been described as a common and serious complication of COVID-19. However, multiple factors that are involved in the development of this complication have been modified throughout these months, including the appearance of new variants of the virus, the modification of treatment protocols or the advancement of vaccination among the general population.

In this study, we aimed to compare the rates of AKI among patients who required admission due to COVID-19 in the first and current (sixth) waves of the pandemic.

METHOD

Consecutive patients that required admission due to COVID-19 in a tertiary referral hospital during the first (March to May 2020) and current (December 2021) waves of the pandemic were enrolled in the study. Patient characteristics, rates of AKI incidence, 28-day mortality and in-hospital length of stay were compared between groups. Viral infection was confirmed by real-time RT-qPCR in all cases. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines using peak serum creatinine and acute dialysis criteria. Multivariate logistic regression was performed to define potential predictors of AKI.

RESULTS

Table 1 summarizes demographic and clinical characteristics among enrolled patients. Compared with the current wave, patients admitted during the first wave were older, had higher baseline serum creatinine and lower baseline eGFR. During the first wave, patients presented higher peak serum creatinine values and a higher incidence of in-hospital AKI. Age, male sex, hypertension, diabetes, CKD and pandemic wave were included in multivariate logistic regression analysis as potential predictors of AKI. Only past history of hypertension [OR 2.867; 95% confidence interval (95% CI) 1.279–6.424; P-value: .011] and CKD (OR 2.418; 95% CI 1.237–4.73; P-value: .01) independently predicted AKI in the sample.

CONCLUSION

Despite multiple changes that have occurred throughout the pandemic, including new treatment protocols, the appearance of new variants of the virus with different clinical profiles or the extensive application of vaccines, these changes have not translated into a significant decrease in the risk of AKI among patients admitted due to COVID-19, which appears to still be conditioned mainly by comorbidities of each patient, including past history of CKD.

Impact of intra-abdominal pressure on early kidney transplant outcomes

Increased intra-abdominal pressure (IAP) is common among post-surgical patients and may cause organ dysfunction. However, its impact after kidney transplantation on early postoperative complications and graft recovery remains unclear. We designed a prospective, observational cohort study to describe the prevalence and determinants of IAP, as well as its effect on delayed graft function, postoperative complications, and graft recovery. IAP was measured in 205 kidney transplant recipients every 8 h during the first 72 h after surgery using the urinary bladder technique. Intra-abdominal hypertension was defined as IAP ≥ 12 mmHg. Patients were followed for 6 months or until graft failure/death. Mean IAP was 12 ± 3.3 mmHg within the first 24 h. 78% of subjects presented with intra-abdominal hypertension during the first 72 h. Increased IAP was associated with higher renal resistive index [r = 0.213; P = 0.003] and lower urine output [r =  - 0.237; P < 0.001]. 72 h mean IAP was an independent risk factor for delayed graft function [OR: 1.31; 95% CI: 1.13-1.51], postoperative complications [OR: 1.17; 95% CI: 1.03-1.33], and absence of graft function recovery [HR for graft function recovery: 0.94; 95% CI: 0.88-0.99]. Increased IAP was highly prevalent after transplantation and was independently associated with delayed graft function, postoperative complications, and absence of graft function recovery. Routine IAP monitoring should be considered post-transplantation to facilitate early recognition of relevant complications.

MO206MALE SEX IS ASSOCIATED WITH IN-HOSPITAL DEATH IN NON-DIALYSIS CKD PATIENTS WITH COVID-19

Background and Aims

Coronavirus disease (COVID-19), caused by Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) can lead to significant organ injury. CKD has been associated with increased mortality in previous epidemics, and male sex has been correlated with worse outcomes during COVID-19 in the general population. Our aim was to describe the differential effect of sex as a risk factor for in-hospital mortality among non-dialysis CKD subjects.

Method

Multicenter, observational cohort study including 136 adult patients with CKD and 136 age- and sex-matched controls who required admission for COVID-19 in three academic hospitals in Spain. Viral infection was confirmed by real-time RT-qPCR and/or serologic testing in all cases. Disease severity on admission was classified according to the WHO—China Joint Mission Report on COVID-19. The presence of CKD was defined as sustained eGFR <60 and >15 ml/min/1.73m2 within the 6 months prior to COVID-19 hospitalization. Demographic and clinical data were gathered from medical records. Outcomes were recorded during the following 28 days after admission. We applied Cox proportional hazards models, adjusted for age, sex, hypertension, diabetes and severe or critical disease at presentation.

Results

Due to the matched design, no differences were found regarding age and sex between cohorts. CKD patients suffered more frequently from hypertension and diabetes and presented higher 28-day mortality after hospital admission due to COVID-19 compared with age- and sex-matched controls (40.4 vs. 24.3%; P=0.004). In adjusted Cox regression analysis among CKD patients, only age (HR: 1.087, 95% CI: 1.047-1.128) and male sex (HR: 1.883, 95% CI: 1.045-3.391) were independent predictors of 28-day mortality. Comparatively, among patients without CKD, only age acted as an independent predictor for 28-day mortality (HR: 1.082, 95% CI: 1.033-1.133). None of the variables included in adjusted regression was able to predict ICU admission in any of the cohorts.

Conclusion

Male sex is associated with increased mortality, but not with ICU admission, after hospitalization due to COVID-19 among non-dialysis CKD patients. That effect was not observed among hospitalized controls without CKD.

MO381RISK FACTORS FOR AKI DURING COVID-19 AMONG NON-DIALYSIS CKD PATIENTS

Background and Aims

AKI is a strong risk factor for adverse outcomes during Coronavirus disease (COVID-19) in the general population. CKD has been correlated with increased risk of AKI both in the outpatient and inpatient settings. We aimed to define potential risk factors for AKI among patients with non-dialysis CKD admitted due to COVID-19.

Method

Multicenter, observational cohort study including 136 adult patients with CKDand 136 age- and sex-matched controls who required admission for COVID-19 in three academic hospitals. Viral infection was confirmed by real-time RT-qPCR and/or serologic testing in all cases. Disease severity on admission was classified according to the WHO—China Joint Mission Report on COVID-19; briefly subjects with COVID-19 were divided into mild (laboratory confirmed, without pneumonia), moderate (laboratory confirmed with pneumonia), severe (dyspnea and/or lung infiltrates >50% of the lung field within 24–48 h) and critical (respiratory failure requiring mechanical ventilation, shock, or other organ failure that requires intensive care). AKI was defined using the 2012 KDIGO classification. CKD was defined as sustained eGFR <60 and >15 ml/min/1.73m2 within the 6 months prior to COVID-19 hospitalization. Baseline eGFR was calculated using the CKD-EPI equation. Demographic and clinical data were gathered from medical records. Outcomes were recorded during the following 28 days after admission. We applied logistic regression analysis to describe potential predictors for AKI.

Results

Median age was 80 years (IQR: 70-86). 58.8% of patients were males. The most common symptom on admission was fever (68.8%), followed by cough (57.7%). The majority of subjects presented with severe COVID-19 on admission (75.7%). During 28-day follow-up, 87 patients (32%) developed Stage 1 AKI, 17 subjects (6.3%) developed Stage 2 AKI and 12 patients (4.4%) developed Stage 3 AKI.

AKI was more frequent (61 vs 24.3%) and more severe (Stage 2 AKI: 10.3 vs 2.2%; Stage 3 AKI: 6.6 vs 2.2%) among CKD patients. In adjusted logistic regression analysis, only disease severity and baseline eGFR were independent predictors for AKI in COVID-19 patients that required hospitalization.

Conclusion

CKD patients suffer AKI more frequently and of higher severity during COVID-19. Baseline eGFR, along with COVID-19 severity, are strong predictor factors of AKI in this setting.

Validation of a survival benefit estimator tool in a cohort of European kidney transplant recipients

Pre-transplant prognostic scores help to optimize donor/recipient allocation and to minimize organ discard rates. Since most of these scores come from the US, direct application in non-US populations is not advisable. The Survival Benefit Estimator (SBE), built upon the Estimated Post-Transplant Survival (EPTS) and the Kidney Donor Profile Index (KDPI), has not been externally validated. We aimed to examine SBE in a cohort of Spanish kidney transplant recipients. We designed a retrospective cohort-based study of deceased-donor kidney transplants carried out in two different Spanish hospitals. Unadjusted and adjusted Cox models were applied for patient survival. Predictive models were compared using Harrell’s C statistics. SBE, EPTS and KDPI were independently associated with patient survival (p ≤ 0.01 in all models). Model discrimination measured with Harrell’s C statistics ranged from 0.57 (KDPI) to 0.69 (SBE) and 0.71 (EPTS). After adjustment, SBE presented similar calibration and discrimination power to that of EPTS. SBE tended to underestimate actual survival, mainly among high EPTS recipients/high KDPI donors. SBE performed acceptably well at discriminating post-transplant survival in a cohort of Spanish deceased-donor kidney transplant recipients, although its use as the main allocation guide, especially for high KDPI donors or high EPTS recipients requires further testing.

P1714INTRA-ABDOMINAL PRESSURE IS ASSOCIATED WITH HIGHER RENAL RESISTIVE INDEX AFTER RENAL TRANSPLANTATION

Background and Aims

The renal arterial resistive index (RRI) reflects renal hemodynamics non-invasively using Doppler arterial waveforms. RRI is defined by factors such as age, sex, weight, height or mean arterial pressure. Intra-abdominal hypertension (IAH) is a common complication among post-surgical patients that can affect renal blood flow. We aimed to determine the relationship between intra-abdominal pressure (IAP) and RRI in a sample of incident kidney transplant patients (KTs).

Method

Single-center prospective cohort of deceased-donor KTs. Anesthesia, surgical technique and immunosuppression induction therapy was the same in all cases. IAP monitoring was performed according to WSACS guidelines using the urinary bladder technique (UnoMeter Abdo-Pressure kit). IAP values were registered every 8h during the first 72h after surgery or until reoperation. Mean IAP values during the first 24h (24h-IAP) were used in this analysis. Doppler ultrasonography was performed 24h after surgery. RRI was calculated using the following formula: (peak systolic velocity – end-diastolic velocity)/peak systolic velocity. The study was approved by the local ethics committee and written informed consent was obtained in all cases.

Results

137 patients were enrolled. Table 1 summarizes relevant patient and hemodynamic variables. Stepwise multivariate linear regression analysis was used to examine independent predictors of RRI in this sample, including all variables in Table 1. Age (β=0.005, std.error=0.001, P&lt;0.001), dialysis vintage (β=0.001, std.error&lt;0.001, P=0.02) and 24h-IAP (β=0.005, std.error=0.003, P=0.041) were independent predictors of RRI.

Conclusion

Increased IAP in the first 24h after surgery is common in KTs and is correlated with higher RRI, which is associated with increased risk of graft loss and death.

P0575TIME TO NEPHROLOGY CONSULTATION AND MORTALITY RISK IN COMMMUNITY ACQUIRED AKI

Background and Aims

Acute Kidney Injury (AKI) is the most frequent cause of Nephrology consultation. Although time to nephrology consultation (TNC) has been object of study, few works focus on its influence on in-hospital mortality in patients with community acquired AKI (CA-AKI).

Method

We picked cases of CA-AKI, and divided individuals in dead in-hospital and survivors. We analyzed clinical and epidemiological variables, and categorized AKI with the KDIGO-2012 stages. We compared clinical outcomes and influence of TNC in mortality.

Results

We included 420 patients, 92 (22%) in the mortality group. These individuals were older, had higher Charlson’s Index, were hospitalized in critical care units, and were classified in KDIGO-2012 Stage 3 more frequently (Table 1). TNC was higher in the dead patients and was significantly associated with mortality HR 1.28 (CI 95% 1.03-1.55, P=0,009). In KDIGO Stages 1 and 2 TNC was shorter in the survivors group, and in Stage 3 we found no differences. In general wards (medical and surgical), TNC was higher in the mortality group, with no differences in the consults from critical units (Table 1). In the survival curves we observe a decline in survival in patients with TNC ≥2 days since admission (Figure 1).

Conclusion

We found that a longer TNC was associated with a poorer survival. This finding would indicate that earlier nephrology attention could impact in-hospital mortality. We interpret the longer TNC in less severe AKI stages as a warning of the unawareness and late recognition of AKI in other specialties. More well designed and larger studies are needed to prove that electronic alerts offer a survival benefit.

P1717OUTCOMES OF INCREASED INTRA-ABDOMINAL PRESSURE AFTER KIDNEY TRANSPLANTATION

Background and Aims

Increased intra-abdominal pressure (IAP) is commonly found among post-surgical patients and can induce organ dysfunction. However, its prevalence and impact after kidney transplantation have not been adequately described. We aimed to study the prevalence of increased IAP after kidney transplantation and its consequences on transplant outcomes.

Method

IAP was prospectively measured in 121 kidney transplant recipients every 8h during the first 72h after surgery using the urinary bladder technique (UnoMeter Abdo-Pressure kit). Mean IAP values during the first 24h (24h-IAP) were used in this analysis. Grading of intra-abdominal hypertension was defined according to WSACS guidelines. Patients were followed for at least 12 months or until graft failure or death. The study was approved by the local ethics committee and informed consent was obtained in all cases.

Results

24h-IAP was 12.6±3.5 mmHg. 84.2% of subjects presented with intra-abdominal hypertension during the first 72h after kidney transplantation. Body mass index (OR: 1.35, 95% CI 1.12-1.63; P=0.002), male sex (OR: 3.34, 95% CI 1.1-10.3; P=0.032) and hemodialysis as renal replacement therapy before transplantation (OR: 4.35, 95% CI 1.32-14.4; P=0.016) were independent determinants of intra-abdominal hypertension. IAP was an independent risk factor for delayed graft function (*model adjusted for recipient age, sex, history of previous kidney transplants, recipient comorbidities, donor terminal serum creatinine and comorbidities, number of HLA mismatches &gt;4, cold ischemia time and donation after cardiac death status), graft failure and death (**model adjusted for all variables included in the previous model plus delayed graft failure) (Figure).

Conclusion

Increased IAP was highly common after transplant surgery and was associated with higher rates of delayed graft function, graft failure and death. Routine IAP monitoring should be considered after transplantation to facilitate early identification of complications and initiation of the appropriate treatment to stop its effects.

P0208DIFFERENTIAL ADAPTATION OF RENAL FUNCTION IN TWO TYPES OF INTENSE PHYSICAL EXERCISE

Background and Aims

Marathon running induces AKI even in adequately prepared and healthy athletes. Heat stress, maintained during more than 2h, has been proposed as one of the leading causes of AKI in marathons runners. Other possible explanations of AKI in this setting could be associated with a reduction of blood supply to the kidneys during the exercise, inadequate hydration or actual structural damage due to microtraumatisms. However, the effect of vigorous exercise of shorter duration on renal function has not been previously described although most risk factors described could also affect kidney function in this type of physical activity.

Method

40 volunteer healthy athletes were enrolled in this study. Subjects participated in two physical tests (10km running, 1.5km swimming) which were separated by at least two weeks from each other. These tests were chosen because of their similar oxygen consumption rate and metabolic load. Vitals, blood and urine samples were collected immediately before and after each test. Informed consent was obtained from all participants. The project was funded by Consejería de Sanidad, Junta de Castilla y León (GRS1732/A/18).

Results

Athletes ranged from 23 to 53 years old. 35% were female. A comparison of hemodynamic and analytical parameters is summarized in Table 1. Running induced a significantly higher rise of serum creatinine and inflammatory markers compared to swimming. Additionally, running caused an increment of serum phosphorus and uric acid levels. Both types of exercise caused a mild increase of urinary albumin/creatinine ratio.

Conclusion

Compared to swimming, running was associated with a greater rise of serum creatinine, possibly linked to a higher degree of acute inflammation and blood flow redistribution to the muscles. The rise of serum uric acid levels may be associated with increased metabolism and reduced elimination of this molecule while running.