[Usefulness of renal resistive index in the diagnosis and evolution of the obstructive uropathy. Experimental study]. / Utilidad del indice de resistencia renal en la valoración y evolución de la uropatía obstructiva. Estudio experimental.

OBJECTIVE: The study was focused on determining the effectiveness and reliability of using the renal resistance index as a method of diagnosing and monitoring the evolution of obstructive uropathy treatment. For this purpose, we conducted an experimental study on a homogenous group of animals that all had the same level of obstruction. MATERIAL AND METHODS: 15 healthy female pigs were used. The experiment was divided into three phases: phase I consisted of a study prior to unilateral pyeloureteral junction obstruction, performing retrograde ureteropyelography, renal B-mode ultrasound and duplex-Doppler (of both kidneys) at a level of the arcuate arteries. Then, the obstruction was performed on the animals. Phase II commenced by diagnosing the lesion, 6 weeks after the previous phase, by means of the aforementioned diagnostic methods. Finally, the endourological treatment was completed. Animals were monitored (Phase III) 15 weeks after the endopyelotomy, using the same methods as in the study, by assessing the urinary tract (fluoroscopy) and both kidneys by determining the renal resistance index and ratio. RESULTS: All the animals in the study showed signs of urinary obstruction on radiology and renal ultrasound 6 weeks after ureteral ligature. After treatment and follow-up, all animals showed signs of having recovered from the obstructive uropathy. Values of deltaRI during the 3 phases are detailed below. Fase I deltaIR = 0.01, Fase II deltaIR = 0.11, Fase III deltaIR = 0.02. CONCLUSION: RI determination using duplex-Doppler is effective for distinguishing obstructive dilatation using non-invasive techniques. However, this parameter provides very slight differences and it can also be influenced by too many direct and indirect factors (observational, patient age, anaesthesia, haemodynamic parameters, etc.), to supplant the classic diagnostic methods.

Utilidad del índice de resistencia renal en la valoración y evolución de la uropatía obstructiva. Estudio experimental / Usefulness of renal resistive index in the diagnosis and evolution of the obstructive uropathy. Experimental study

Objetivo: El planteamiento del estudio va enfocado a determinar la efectividad y fiabilidad de la medición del índice de resistencia renal (IR) para el diagnóstico y evolución tras el tratamiento de la uropatía obstructiva. Para ello realizamos un estudio experimental con un grupo homogéneo y con un grado de obstrucción uniforme. Material y métodos: Se emplean 15 animales de la especie porcina, todas hembras sanas. El planteamiento experimental está vertebrado en tres fases; la primera consiste en el estudio previo a la obstrucción de la unión pieloureteral unilateral mediante ureteropielografía retrógrada, nefrosonografía en modo B y dúplex-Doppler (ambos riñones) al nivel de las arterias arciformes. Posteriormente se procede a la creación del modelo animal de obstrucción. La Fase II comienza con el diagnóstico de la lesión 6 semanas después de la anterior fase, mediante los medios diagnósticos citados. Finalmente se completa el tratamiento endourológico. El seguimiento de los animales (Fase III) se realiza transcurridas 15 semanas tras la endopielotomía, valorando al igual que durante el estudio, la vía urinaria (fluoroscopia) y la afectación en ambos riñones mediante la determinación del índice de resistencia renal y su ratio. Resultados: Todos los animales del estudio mostraron signos radiológicos y nefrosonográficos de obstrucción urinaria tras 6 semanas de la ligadura ureteral. Tras el tratamiento y seguimiento todos los animales mostraron signos de recuperación de la uropatía obstructiva. Los valores del DeltaIR a lo largo de las 3 fases se detallan a continuación. Fase I DeltaIR = 0.01, Fase II DeltaIR = 0.11, Fase III DeltaIR = 0.02. Conclusiones: La valoración del IR mediante dúplex-Doppler es efectiva para la diferenciación de la dilatación obstructiva mediante técnicas no invasivas. Pero este parámetro aporta unas diferencias muy leves y además puede verse afectado por demasiados factores de modo directo o indirecto (observador, edad del paciente, anestesia, parámetros hemodinámicos, etc.), como para relegar los métodos de diagnóstico clásicos

Objective: The study was focused on determining the effectiveness and reliability of using the renal resistance index as a method of diagnosing and monitoring the evolution of obstructive uropathy treatment. For this purpose, we conducted an experimental study on a homogenous group of animals that all had the same level of obstruction. Material and methods: 15 healthy female pigs were used. The experiment was divided into three phases: phase I consisted of a study prior to unilateral pyeloureteral junction obstruction, performing retrograde ureteropyelography, renal Bmode ultrasound and duplex-Doppler (of both kidneys) at a level of the arcuate arteries. Then, the obstruction was performed on the animals. Phase II commenced by diagnosing the lesion, 6 weeks after the previous phase, by means of the aforementioned diagnostic methods. Finally, the endourological treatment was completed. Animals were monitored (Phase III) 15 weeks after the endopyelotomy, using the same methods as in the study, by assessing the urinary tract (fluoroscopy) and both kidneys by determining the renal resistance index and ratio. Results: All the animals in the study showed signs of urinary obstruction on radiology and renal ultrasound 6 weeks after ureteral ligature. After treatment and follow-up, all animals showed signs of having recovered from the obstructive uropathy. Values of DeltaRI during the 3 phases are detailed below. Fase I DeltaIR = 0.01, Fase II DeltaIR = 0.11, Fase III DeltaIR = 0.02. Conclusion: RI determination using duplex-Doppler is effective for distinguishing obstructive dilatation using non-invasive techniques. However, this parameter provides very slight differences and it can also be influenced by too many direct and indirect factors (observational, patient age, anaesthesia, haemodynamic parameters, etc.), to supplant the classic diagnostic methods