Francisco Javier Rubio Castañeda

Introduction: Postoperative isometric exercises promote the maturation of native arteriovenous fistulas.Objective: To determine whether the use of a handgrip influences arteriovenous fistula maturation and to analyse its relationship with sex.Material and Method: Prospective observational study. Population: patients with mature radiocephalic fistulas who performed handgrip exercises. Exercise protocol: initiation 15 days after surgery. A total of 20 repetitions were performed 5 times per day with progressive increase in resistance every 15 days. Ultrasound measurements: at 30 and 75 days.Results: The sample included a total of 21 patients, 66.7% men. Men achieved significantly higher radial artery peak systolic velocity and venous diameter in all ultrasound measurements (P<0.05). At 75 days, those who used a maximum resistance of 40 kg showed greater radial artery peak systolic velocity (114.1 vs 85.3; P=0.049), venous diameter (6.87 vs 5.83; P=0.021), and vascular access flow (1465 vs 795; P=0.002) vs those who used 24 kg. In addition, they showed greater radial artery peak systolic velocity (114.1 vs 98.2; P=0.032) and venous diameter (6.87 vs 6.24; P=0.046) vs those who used 32 kg. The maximum resistance used was significantly correlated with radial artery peak systolic velocity (r=0.5; P=0.004), venous diameter (r= 0.57; P=0.006), and vascular access flow (r=0.58; P=0.027). When stratified by sex, a significant correlation was observed only in men.Conclusions: Men use higher resistance levels than women in handgrip isometric exercises. Furthermore, men achieve better morphological and haemodynamic parameters in all ultrasound measurements.

Objective: To determine the preoperative and postoperative inflammatory, biochemical, and haematological factors that influence the maturation of native arteriovenous fistulas. Material and Method: We conducted a retrospective observational study. Two blood tests were performed—pre- and postoperative—analysing biochemical, haematological, and inflammatory parameters. Statistical analysis included descriptive statistics, Student’s t test, Mann–Whitney U test, chi-square test, Wilcoxon test, and binomial logistic regression. Results: The sample comprised 130 patients with a mean age of 68.3 years; 75.3% were men. Overall, 75.3% of fistulas matured. When comparing mature versus non-mature fistulas, the following findings were observed: Preoperative analysis: albumin (p=0.012) and PO2 (p=0.007) were significantly higher, and C-reactive protein (CRP) (p=0.006) was significantly lower in mature fistulas. Postoperative analysis: CRP (p=0.004) and creatinine (p=0.002) were significantly lower in mature fistulas. Paired-sample analysis: in mature fistulas, there was a significant postoperative increase in PO2 (p=0.049), leukocytes (p=0.021), and neutrophils (p=0.011), and a significant postoperative decrease in PCO2 (p=0.042) and creatinine (p<0.001). In non-mature fistulas, a significant decrease in preoperative albumin was observed (p<0.001). Logistic regression: higher preoperative albumin (OR, 0.15; p=0.003) and PO2 (OR, 0.54; p=0.002) were associated with a lower risk of maturation failure. Higher preoperative uric acid (OR, 1.58; p=0.005), and higher postoperative CRP (OR, 1.31; p=0.047) and creatinine (OR, 1.22; p=0.006) were associated with a greater risk of maturation failure. Conclusions: Elevated uric acid, creatinine, and CRP levels increase the risk of fistula maturation failure, whereas higher preoperative albumin and PO2 reduce this risk.

Background/Objectives: Weight gain after kidney transplantation is frequent but heterogeneous, often accompanied by changes in body composition that influence long-term outcomes. This study analysed one-year changes in body compartments and their demographic and clinical determinants. Methods: A prospective cohort of 112 adult kidney recipients transplanted between September 2020 and June 2022 at a Spanish tertiary hospital was followed. Body weight, muscle mass, fat mass, visceral fat and total body water were assessed by multi-frequency bioelectrical impedance at discharge, and at 3, 6 and 12 months. Associations with sociodemographic, clinical and comorbidity variables were examined using repeated-measures ANOVA and comparative tests. Results: At 12 months, mean weight gain was 3.6 ± 6.5 kg (5.1%). Increases were greater in men, younger patients, non-dialysis candidates, those with previous transplantation and living donor grafts. Muscle mass rose during the first three months and then stabilised, with greater gains in men and haemodialysis patients. Fat mass decreased initially and then increased, particularly in women, younger recipients and living donor transplants. Visceral fat progressively increased after three months, with higher levels in men and older patients. Total body water declined in women, younger recipients and first transplant patients. Patients with new-onset diabetes gained less weight, while smokers gained more. Conclusions: Post-transplant body composition is shaped by sex, age, BMI, comorbidities and donor type. Monitoring compartments beyond body weight may allow early detection of adverse metabolic trajectories. Tailored nutritional and lifestyle interventions are needed to optimise long-term outcomes.

Background/Objectives: Individuals with chronic kidney disease often face significant physical and clinical challenges, such as muscle weakness, fatigue, and reduced cardiorespiratory capacity, that impact their quality of life. Physical activity has emerged as an effective intervention to counteract these effects, with clinical guidelines recommending exercise as a standard treatment for kidney transplant recipients. The aim of this study was to assess pretransplant physical activity levels in a cohort of transplant patients and analyze their relationships with cardiovascular risk factors. Methods: A cross-sectional, analytical, and correlational study was conducted from September 2020 to June 2022 with a sample of 122 kidney transplant recipients assessed before kidney transplantation. Sociodemographic data, anthropometric data, comorbidities, renal replacement therapy types, and clinical and analytical data were collected from the patients’ clinical records. Physical activity was assessed via the International Physical Activity Questionnaire. Results: The average time spent waiting for transplantation was 423 ± 405 days, which was longer (387 ± 524) in the group of those under 65 years than in those over 65 years (194 ± 256) (p = 0.010). The median energy expenditure was 1742 (IQR = 1719) METs. In addition, 15.6% of the participants reported inactivity. Men reported higher physical activity levels (median: 2076 METs/week; IQR: 2037) than women did (median: 1386 METs/week; IQR: 1238). A higher level of physical activity was found in non-dialysis patients, overweight patients, and those with a history of stroke. A significant positive correlation was found between physical activity levels and serum urea. Conclusions: Increased physical activity levels were observed in men and in participants under 65 years of age. Patients with cardiovascular risk factors, such as hypertension, diabetes mellitus, dyslipidemia, overweight and obesity, reported lower activity levels, whereas those with a prior history of cerebrovascular accidents engaged in more physical activity. This study highlights the importance of assessing physical activity and promoting exercise for chronic kidney disease patients awaiting kidney transplantation. Further research is needed to explore the evolution of physical activity in this population and its impact post-transplantation.

Introduction: Primary failure includes early thrombosis and maturation failures. Objectives: To determine the risk factors associated with primary failure of native fistulas and their relationship with survival. To analyse the sonographic differences between mature fistulas and fistulas with maturation failure. Material and Method: Observational and retrospective study. Variables: sociodemographic, anthropometric, comorbidities, blood and ultrasound parameters. Statistical analysis: Descriptive. Logistic regression. Kaplan-Meier method. Results: Sample 65 native fistulas, 72.3% male. Age 69.7 years. 60% mature fistulas and 40% fistulas with primary failure (20% maturation failure and 20% early thrombosis). Risk factors for maturation failure: arterial diameters <2 mm (OR:16.8; p=0.016). Risk factors for early thrombosis: age ≥65 years (OR:5.44; p=0.014), weight (OR:1.04;p=0.02) and body mass index (OR:1.17;p=0.027). Monocytes as a protective factor for early thrombosis (OR:0.0142; p=0.029).People ≥ 65 years old, obese, and with arterial diameters <2 mm had lower survival. Mature fistulas had a significantly higher vein diameter, peak systolic velocity, and vascular access flow (p<0.001). Conclusions: Fistulas performed with arterial diameters <2 mm present a higher risk of maturation failure. The higher the age, weight, and body mass index, the higher the risk of early thrombosis. The fewer monocytes, the lower the risk of early thrombosis. Age, arterial diameter, and weight influence survival. There are ultrasound differences between mature fistulae and fistulae with maturation failure.

Introduction: Different first-generation methods exist for the detection of stenosis. Objective: To determine the accuracy of first-generation methods in detecting stenosis in native arteriovenous fistulas. Method: Retrospective observational study. Sample: Patients with functioning native arteriovenous fistulas. First-generation methods include physical examination, manual tests, pulse increase test and arm elevation test, indirect methods, Kt/V, and arteriovenous fistula recirculation. The diagnosis of stenosis was confirmed by Doppler ultrasound. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of first-generation methods based on Doppler ultrasound were calculated. Results: Sample 39 patients, 79.48% male. Ultrasound detected 19 stenoses, nonsignificant. Physical examination: sensitivity 31.5%, specificity 80%, PPV 60%, NPV 55.1%, accuracy 56.4%. Pulse rise test: sensitivity 5.2%, specificity 90%, PPV 33.3%, NPV 50%, accuracy 48.7%. Arm elevation test: sensitivity 52.6%, specificity 70%, PPV 62.5%, NPV 60.8%, accuracy 61.5%. Indirect methods: sensitivity 15.7%, specificity 55%, PPV 25%, NPV 40.7%, accuracy 35.9%. Kt/V: sensitivity 10.5%, specificity 75%, PPV 28.5%, NPV 46.8%, accuracy 43.5%. AVF recirculation: sensitivity 10.5%, specificity 100%, PPV 100%, NPV 54.1%, accuracy 56.4%. Conclusions: All first-generation methods have high specificity and low sensitivity. The degree of stenosis (significant or non-significant) could influence the sensitivity of the physical examination but not the specificity. The arm elevation test is the most accurate first-generation method of detecting stenosis.

Introduction: Weight gain after kidney transplant has been documented, among other factors, due to reduced physical activity in the early months, increased appetite, and the use of immunosuppressants and corticosteroids. Objective: To understand post-transplant weight gain. Indeed, to determine the relationship between weight gain and comorbidities, as well as, to evaluate changes in body composition. Material and Method: Prospective study, September 2020 to April 2023. Weight measurements were taken at 0, 3, 6, and 12 months. Results: Ninety-two patients were analyzed, 68.5% male, with an average age of 58±18.5 years. Pre-transplant weight was 72.5 (±5.8) kg, and at 12 months, it was 75.10 (±15.7) kg. Differences were found between first-time and repeat transplants (p=0.020). In the analysis of repeated measures of weight (p=0.022), differences were observed between month 0 and the third month, month 0 and one year, and between the third month and one year.In muscle mass (p<0.001), differences were seen when comparing month 0 with the third, sixth, and twelfth months. Fat mass differed when comparing the third month with the twelfth month, and visceral fat (p=0.032) differed when comparing the third month with the sixth and twelfth months. Conclusion: After a kidney transplant, weight gain occurs, especially after the sixth month, reaching 5% per year. Muscle mass increases more than fat mass. People who received kidneys from living donors, those with previous transplants, and those with hypertension and/or cardiovascular disease experience greater weight gain.

Introduction: Doppler ultrasound and dilutional methods allow monitoring of vascular access flow. The presence of collateral veins may influence the determination of vascular access flow.Objective: To determine the influence of collateral veins on the vascular access flow measurement by Doppler ultrasound and by the thermodilution method. Material and Method: Observational and prospective study. Native arteriovenous fistulas that met the selection criteria were selected. An annual measurement of vascular access flow by Doppler ultrasound and two quarterly thermodilution measurements (thermodilution-1 and thermodilution-2) were performed. Ultrasound was used to determine the presence of collateral veins.Results: Thirty-eight native arteriovenous fistulae were analysed. Males accounted for 78.9% of the sample. Collateral veins were present in 23.6% of cases. Analysing the whole sample, a linear correlation was obtained between ultrasound-Doppler flows with thermodilution-1 (0.694) and thermodilution-2 (0.678), [both p<0.001]. When stratified by collateral veins, when no collateral veins were present, there was a significant correlation between Doppler ultrasound with thermodilution-1 (0.698) and thermodilution-2 (0.696) [both p<0.001)]; whereas the correlation was non-significant when collateral veins were present.Conclusions: There is correlation between vascular access flow measurement obtained by Doppler ultrasound and thermodilution; the presence of collateral veins modifies such relationship. It is necessary to implement vascular access surveillance programs that include different monitoring methods in order to mitigate the effect of collateral veins on vascular access flow determination.

Physical activity contributes to improve health and reduce mortality in older people. The objective was to analyze the validity of content and reliability of the short version of IPAQ-E in elderly people who attended to Fernando el Católico health center between May 2013 and March 2015. Validation study of the short version of the international physical activity questionnaire (IPAQ) adapted in Spanish elderly (IPAQ-E). Our sampling was for convenience. The short version of IPAQ in Spanish USA was used and its activities were adapted to Spanish elderly. Two measurements of IPAQ-E with 15 days between them were used to analyze the intraobserver reliability. The intraclass correlation coefficient was used to measure intraobserver reliability, Cronbach's alpha for internal consistency (CI) and Spearman correlation coefficients (CS) to analyze the correlation between IPAQ-E and the Short Physical Performance Battery (SPPB). The sample was 139 people, average age 73,18 years. Intraobserver reliability total was 0.914, besides exceeded 0.9 in the three dimensions of the questionnaire. The CI was 0.518; It exceeded 0.8 in the rest of dimensions of IPAQ-E. The CS between IPAQ-E Total and SPPB was (Rho 0.435), between the total scores SPPB and walking activity was (Rho 0.426), and the score vigorous activity was (Rho 0,248). The IPAQ-E is a valid and reliable instrument for measuring mobility in Spanish elderly. However, more studies about its validity will be required in the future.

La actividad física en las personas mayores contribuye a mejorar su estado de salud y a disminuir la mortalidad. El objetivo fue analizar la validez de contenido y fiabilidad de la versión corta del cuestionario internacional de la actividad física adaptado a personas mayores de 65 años (IPAQ-E) en el centro de salud Fernando el Católico de Zaragoza entre mayo 2013 y marzo de 2015. Estudio de validez de contenido y fiabilidad del IPAQ-E. Se realizó muestreo por conveniencia. Se utilizó la versión corta del IPAQ en español de Estados Unidos y se adaptó a actividades realizadas por personas mayores españolas. Para analizar la fiabilidad intraobservador se realizaron dos mediciones del IPAQ-E con 15 días de diferencia. Se utilizó el coeficiente de correlación intraclase para la fiabilidad intraobservador, el alfa de Cronbach para la consistencia interna (CI) y el coeficiente de Spearman (CS) para analizar la correlación entre IPAQ-E y Short Physical Performance Battery (SPPB). Participaron 139 personas, edad media de 73,18 años. Fiabilidad intraobservador total 0,914 y superó el 0,9 en las tres dimensiones del cuestionario. CI 0,518; superó el 0,8 en el resto de dimensiones del IPAQ-E. CS entre IPAQ-E total y SPPB (Rho 0,435 y p < 0,01), y entre puntuaciones totales del SPPB con actividades caminar (Rho 0,426 p < 0,01) y vigorosas (Rho 0,248 p< 0,01). El IPAQ-E es un instrumento válido y fiable para medir la movilidad en personas mayores españolas. Son necesarios más estudios para añadir información sobre la validez de este instrumento.