C. Hernandez-Fernandez

Sildenafil as a Protecting Drug for Warm Ischemic Kidney Transplants: Experimental Results

PURPOSE In an experimental model we studied the protective effects of the phosphodiesterase-5 inhibitor sildenafil on kidney grafts autotransplanted after 45 minutes of warm ischemia by vascular clamping, nephrectomy and 60 minutes of isolated hypothermic pump perfusion. MATERIALS AND METHODS A total of 14 laboratory minipigs were divided into group 1-7 administered 100 mg sildenafil orally 1.5 hours preoperatively and group 2-7 in which no sildenafil was given. Right single nephrectomy was completed after 45 minutes of warm ischemia by complete vascular clamping. Before autotransplantation all kidneys underwent 60 minutes of hypothermic pulsatile perfusion. Renal flow, arterial pressure and renal vascular resistance were recorded in real time for 60 minutes after autotransplantation. Nitric oxide levels were determined in blood samples from the renal vein at predefined intervals. Optical and electronic microscopy was done in all organs at the end of the procedure. RESULTS In group 1 vs 2 renal vascular flow was significantly higher (155.30 vs 29.04 ml per minute per 100 gm) and renal vascular resistance was significantly lower (0.59 vs 3.10 mm Hg/ml per minute, each p <0.01). No significant differences were observed in systemic arterial pressure between groups 1 and 2 (84.08 and 84.65 mm Hg, respectively, p >0.05). Nitric oxide levels were significantly higher for all periods in group 1 (49.94 vs 16.85 muM, p <0.01). No significant differences were observed in histological studies, although endothelial cell structure was better preserved in the sildenafil group. CONCLUSIONS To our knowledge our study suggests for the first time in the literature a positive effect of sildenafil in the immediate posttransplantation outcome of warm ischemic kidneys without secondary systemic effects.

Hydrodynamic and biochemical effects of isolated hypothermic renal perfusion depending on the pump model and perfusion solution

OBJECTIVES To evaluate hydrodynamic, biochemical, and histological consequences of hypothermic isolated renal perfusion using a new computerized perfusion system. MATERIALS AND METHODS The device that allowed us to obtain on renal hydrodynamics during perfusion included multiple parts. The organ was perfused at 4 degrees C with a constant flow either using a classic roller pump or a pump designed in our laboratory to employ vacuum or atmospheric pressure sequentially to achieve a truly pulsatile wave (vacuum-powered tubular pump). The study included 16 minipigs with Eurocollins or Belzer perfusion solutions sampled at predefined interval and histological studies of the organs performed. RESULTS There was a significant difference in weight increase between the two types of pumps; those perfused with Eurocollins showed greater values than those with Belzer solution. Onset of nitric oxide (NO) in the perfusion solution increased inversely with the renal vascular resistance. The highest NO levels were observed with the Belzer solution and vacuum pump. CONCLUSIONS Changes in renal hydrodynamics, as induced by perfusion wave form and solution type, may be recorded in real time using a computerized system. A vacuum pump with the Belzer solution achieved the best experimental results.

Intravenous Sildenafil as a Preconditioning Drug Against Hemodynamic Consequences of Warm Ischemia-Reperfusion on the Kidney

PURPOSE We designed an experimental model of renal ischemia-reperfusion to evaluate the preemptive effect of intravenous sildenafil according to the dose administered (0.7 vs 1.4 mg/kg) and the time of administration (30 minutes before ischemia or during ischemia). MATERIALS AND METHODS A total of 20 minipigs were divided into groups of 4 each, including group 1-control, group 2-sildenafil 0.7 mg/kg intravenously 30 minutes before vascular clamping, group 3-sildenafil 0.7 mg/kg intravenously during warm ischemia, group 4-sildenafil 1.4 mg/kg intravenously 30 minutes before vascular clamping and group 5-sildenafil 1.4 mg/kg intravenously during warm ischemia. The ischemia-reperfusion model was applied using laparotomy and right kidney vascular clamping for 30 minutes, followed by unclamping and reperfusion for 45 minutes. Renal vascular flow and systemic mean arterial pressure were recorded for 45 minutes after unclamping. Mean values were compared using Student t test with significance considered at p <0.05. RESULTS Sildenafil led to a decrease in arterial pressure compared to that in controls, especially at the dose of 1.4 vs 0.7 mg/kg, including 113.77, 109.76, 106.12, 97.41 and 82.85 mm Hg in groups 1 to 5, respectively. Renal vascular flow was significantly higher in groups 2 and 3 than in groups 1, 4 and 5 (112.82 and 111.33 vs 88.25, 87.91 and 84.37 ml per minute, respectively, p = 0.000). CONCLUSIONS The effect of intravenous sildenafil as a preemptive drug against the hemodynamic effects of renal ischemia-reperfusion is dose dependent. The 0.7 mg/kg dose significantly increased reperfusion renal vascular flow with a small decrease in arterial pressure compared to the 1.4 mg/kg dose.

Cadaver Donor Kidney Retransplantation in the Pediatric Patient: Complications and Long-Term Outcome

PURPOSE We compared the outcome of second and third kidney allografts with that of the first kidney allograft in pediatric recipients. MATERIALS AND METHODS We classified 173 cadaveric kidney recipients into 2 groups. Group 1 comprised 120 first transplants and group 2 comprised 53 retransplants, including 43 second and 10 third transplants. We compared demographic characteristics and survival in groups 1 and 2. RESULTS Group 1 consisted of 78 boys and 42 girls with a mean ± SD age of 11.5 ± 4.2 years. Group 2 consisted of 37 boys and 16 girls with a mean age of 10.4 ± 4.7 years. One, 5, 10 and 15-year graft survival rates were 78.7%, 64.3%, 54.5% and 50.7% for first transplants vs 82.8%, 57.8%, 57.8% and 41.3%, respectively, for retransplants (p = 0.757). Patient survival at 1, 5 and 15-year was 95.8%, 89.6%, 84.9% in the first transplant group vs 93.6%, 93.6% and 93.6%, respectively, in the retransplant group (p = 0.0.63). Graft survival was significantly higher in patients who did vs did not receive calcineurin inhibitors in the 2 groups (p = 0.02). CONCLUSIONS Kidney retransplantation in the pediatric population can yield excellent long-term outcomes, especially in patients treated with calcineurin inhibitors.

First Percutaneous Computed Tomography-guided Radiofrequency Ablation of Renal Tumor in Horseshoe Kidney

OBJECTIVE To report the first case of percutaneous radiofrequency ablation of a tumor in a horseshoe kidney. MATERIALS AND METHODS A 75-year-old man presented with a 3-cm solid mass on the isthmus of a horseshoe kidney. The tumor was discovered incidentally on a routine computed tomography scan performed during follow-up of a colon carcinoma treated with open hemicolectomy. The patient presented a high anesthetic risk (American Society of Anesthesiologists score of 3) because of a comorbid cardiovascular condition. Biopsy of the mass revealed type I papillary carcinoma. We performed percutaneous radiofrequency ablation using a posterior approach. RESULTS No complications occurred, and postoperative computed tomography 3 months after the procedure showed no significant contrast enhancement in the treated area. CONCLUSIONS To our knowledge, this is the first case of a tumor in a horseshoe kidney satisfactorily treated with percutaneous radiofrequency ablation. The technique could represent an alternative to traditional surgery in selected cases.

Rectourethral Fistula Management.

Rectourethral fistula (RUF) is a rare condition that occurs, in most cases, as a consequence of prostate cancer treatments. Clinical suspicion and proper assessment prior to surgery are essential to adapt and successfully carry out an appropriate treatment plan. There are no randomized trials to guide clinical practice, and therefore, scientific evidence in this respect is limited. Expert recommendations seem to agree on the transperineal approach with flap interposition as the surgical treatment of choice in cases of complex fistulas, especially in those that have undergone prior radiation. Undoubtedly, the key to the successful treatment of the disease is the multidisciplinary and standardized management by physicians with experience in the field.

Trombosis de la vena espermática derecha. Revisión de la literatura a propósito de un caso

Acute thrombophlebitis of spermatic vein is an unusual pathology involving, in most of the cases, the left side, and whose etiology remains uncertain. Most of them are found during a a differential diagnosis in acute testicular pain. We introduce the case of a 29 years old male with abusive cocaine consumption, admitted to hospital due to severe testicular pain. Doppler-ultrasound examination was undertaken, showing right spermatic vein flux alteration. Conservative management was decided and anticoagulant and non-esteroidal anti-inflammatory drugs were started. Eco-doppler is the most specific and sensible technique for diagnosis of these cases, while TC can always confirm etiologic diagnosis. Treatment was initially conservative based on anticoagulation. Hematological study is necessary in order to determine coagulation alterations.espanolLa tromboflebitis aguda de la vena espermatica es una dolencia de muy baja frecuencia, con afectacion mayoritaria del lado izquierdo, y de etiologia desconocida en la mayoria de las ocasiones. Suele ser un hallazgo inesperado en el diagnostico diferencial del dolor testicular agudo. Se trata de un varon de 29 anos con un consumo abusivo de cocaina que acude con dolor testicular agudo. Se confirma la afectacion de la vena espermatica derecha mediante ecografia-doppler. Se opto por manejo conservador con anticoagulacion y antiinflamatorios. La eco-doppler es la tecnica con mayor especificidad y sensibilidad para diagnosticarlo, mientras que la TC puede completar su diagnostico etiologico. El tratamiento de eleccion es conservador basado en la anticoagulacion del paciente. Es imperativo un estudio hematologico en busqueda de alteraciones de la coagulacion. EnglishAcute thrombophlebitis of spermatic vein is an unusual pathology involving, in most of the cases, the left side, and whose etiology remains uncertain. Most of them are found during a a differential diagnosis in acute testicular pain. We introduce the case of a 29 years old male with abusive cocaine consumption, admitted to hospital due to severe testicular pain. Doppler-ultrasound examination was undertaken, showing right spermatic vein flux alteration. Conservative management was decided and anticoagulant and non-esteroidal anti-inflammatory drugs were started. Eco-doppler is the most specific and sensible technique for diagnosis of these cases, while TC can always confirm etiologic diagnosis. Treatment was initially conservative based on anticoagulation. Hematological study is necessary in order to determine coagulation alterations.

Second Cadaveric Kidney Transplantations in the Pediatric Population

OBJECTIVE To evaluate the functional outcomes and complications among a series of second in comparison to first kidney transplantations in pediatric patients. MATERIALS AND METHODS We reviewed 163 consecutive kidney transplants in pediatric recipients performed from 1978 to present: 120 cases (69.3%) were first transplants (group A) and 43 (24.8%), second transplant (group B). We analyzed the incidences of delayed graft function (DGF), medical and surgical complications, as well as medium- and long-term graft survivals. RESULTS We observed DGF among 51 group A patients (43%) versus 32.5% of group B. Ten patients suffered vascular complications in group A (8.3%) versus one in group B (2.3%) (P < .05). The 15-year graft survivals were 54.2% for group A and 45% for group B. The 15-year patient survivals were 84.9% in group A versus 93.6% in group B. CONCLUSIONS Second kidney transplantations for children are a satisfactory option that achieves good functional results as well as acceptable graft and patient survivals.