Evaluation of effects of Extracorporeal Shock Wave Lithotripsy on renal vasculature with Doppler ultrasonography

OBJECTIVES

In this prospective study, we aimed to demonstrate the effects of Extracorporeal Shock Wave Lithotripsy (ESWL) on renal blood flow in patients treated for renal/ ureteral stones.

MATERIAL AND METHODS

The study group comprised 41 patients (26 males, 15 females, aged between 18-63 years, mean age 45 years), 23 with renal and 18 with ureteral stones, who underwent ESWL between March 2010 and January 2011. Colour Doppler ultrasonography and pulsed wave spectral analysis was performed before, 1 hour, and 7 days after ESWL to both ipsilateral and contralateral kidneys in order to measure resistive index (RI), pulsatility index (PI) and acceleration time (AT) values.

RESULTS

One hour after ESWL, RI and PI values showed significant increase from pre-ESWL values in both ipsilateral and contralateral kidneys. However, no significant change was found in AT values. Seven days after ESWL, PI in both ipsilateral and contralateral kidneys and RI in contralateral kidney returned to pre-ESWL values. But, 7 days after ESWL, RI in the ipsilateral kidney did not return to pre-ESWL values, although decrease in RI values were observed. CONCLUSİON: Spectral Doppler analysis can provide valuable information as a non-invasive method to assess the hemodynamic changes and renal microcirculation status in cases managed with ESWL.

[Endovascular radiofrequency denervation of renal arteries as an innovation method of treatment of refractory arterial hypertension. First experience in Russia]

Excessive activation of the sympathetic nervous system forms the basis of pathogenesis of essential arterial hypertension (AH). The present work was aimed at evaluating efficacy and safety of endovascular radiofrequency denervation of renal arteries in patients with AH refractory AH based on the initial first experience in with using this methodology in the Russian Federation. The interventions were carried out on December 14-15th, 2011 in the first five patients presenting with AH refractory to antihypertensive therapy consisting of three and more drugs in therapeutic doses, one of which was a diuretic. The selection criteria were systolic arterial pressure (SAP) ≥160 mm Hg or ≥150 mm Hg in the presence of type 2 diabetes mellitus. The obligatory conditions for selection were the preserved renal function [glomerular filtration rate (GFR) ≥45 ml/min] and the absence of the secondary form of AH. The procedure of denervation was performed in the conditions of roentgen-operating room using special Medtronic Ardian Simplicity Catheter System™. In all cases we managed to perform bilateral denervation of renal arteries with the radiofrequency effect in not less than 4 zones of each of vessels. Efficacy of each of the effect was registered with due regard for reaching certain temperature and values of impedance. The interventions were not accompanied by the development of any complications either in the area of manipulations or the site of puncture. Neither were there any complications from the side of the cardiovascular or excretory systems of the body. Diurnal monitoring of AP (DMAP) registered a significant decrease in SAP averagely from 174±12 to 145±10 mm Hg three days after the intervention. A persistent antihypertensive effect was confirmed by the DMAP findings one month after denervation - the SAP level averagely amounted to 131±6 mm Hg. Endovascular radiofrequency denervation of renal arteries is a safe and efficient method of treatment of AH resistant to multicomponent antihypertensive therapy.

Bilateral renal artery stenosis after abdominal radiotherapy for Hodgkin's disease

A 49-year-old woman was admitted with fatigue, dyspnoea, pretibial oedema and decreased daily urination. Seven years ago she was treated with doxorubicin, bleomycin, vinblastine and dacarbazine, alternating with mechlorethamine, vincristine, procarbazine and prednisone and 80 Gy abdominal radiotherapy for Hodgkin's disease. Two years later, malignant hypertension was diagnosed. Angiotensin-2 antagonist and beta-blocker treatment was given. After increased serum creatinine levels were determined, renal angiography was performed and total obstruction in the left renal artery and near total obstruction in the right side was observed. She was admitted to our clinic with oliguria, and acute renal failure was diagnosed. Balloon angioplasty and stent implantation was performed to the right renal artery. After a polyuric period, serum creatinine reduced to near normal levels. Angiotensin-2 antagonist treatment worsened the course in this patient. Patients with resistant hypertension occurring years after abdominal radiotherapy should be evaluated for renal artery stenosis.

Histomorphometric evaluation of (198)Au endovascular brachytherapy in a renal artery restenosis model in rabbits

OBJECTIVE

The main mid-term complication of percutaneous transluminal angioplasty of the renal artery is restenosis, which occurs in up to 50% of patients. Although no pharmacologic agent to date has been effective in preventing restenosis, both beta-ray emitters and gamma-ray emitters used in endovascular brachytherapy have been shown to reduce coronary restenosis. The objectives of this study were to evaluate the efficacy of (198)Au endovascular brachytherapy in preventing restenosis after percutaneous transluminal renal angioplasty and to determine the radiation dose to the operator.

MATERIALS AND METHODS

Twenty-one New Zealand white rabbits (10 females and 11 males) weighing an average of 3.5 kg (range, 3.2-3.8 kg) who had been fed a normal diet underwent bilateral 33% overdilatation with deendothelialization of the renal arteries. After 7 weeks, the induced renal artery stenoses were treated by percutaneous transluminal renal angioplasty. The rabbits were randomly assigned to one of three groups before receiving endovascular 25-Gy irradiation at a radial 2.0-mm depth with a 0.5 x 15 mm (198)Au wire (106 MBq). The right renal artery was irradiated in group A; the left, in group B. The rabbits in group C randomly received a right- or left-sided dummy wire. Operator exposure to radiation was measured using thermoluminescent dosimeters and ionization chambers. The rabbits were sacrificed after 3 weeks. The aorta and renal arteries were perfusion-fixed. The renal arteries were removed for histologic and histomorphometric study.

RESULTS

Forty-two renal arteries were cut into a series of 4- micro m-thick slices. Five arteries were thrombosed (two in the irradiated group and three in the control group, p > 0.05). In the patent arteries (n = 37), the average neointimal area was 0.068 mm(2) (range, 0.009-0.234 mm(2)) in 15 irradiated segments (315 slices total), whereas the average neointimal area was 0.135 mm(2) (range, 0.016-0.324 mm(2)) in 22 control segments (462 slices total) (analysis of variance, p < 0.009), showing a percentage area of restenosis of 10.4% in irradiated arteries and 43.4% in non-irradiated arteries (p < 0.0003). Radiation dose per procedure to the operator was 0.034 mSv in the index finger, 0.024 mSv in the wrist, and undectable in the body.

CONCLUSION

Endovascular brachytherapy with (198)Au appears to inhibit early renal artery restenosis and exposes the operator to a safe level of radiation.

[The rate of physiological fibrinolysis in the mesenteric and renal vessels of rabbits]

In the rabbit vessels of a. mesenterica, total lysis of fibrin occurred within 60-90 minutes whereas in the renovascular basin the process took 30 minutes longer. This seems to be due to synthesis of a plasminogen activator.

Postradiation renovascular hypertension

Radiation injury to arteries can represent a significant complication of therapeutic irradiation, even when the dosage used has not been excessive as judged by approved protocols. Children in whom therapeutic abdominal irradiation has been used should be monitored indefinitely for the development of hypertension. The presence of hypertension in such children with normal blood urea nitrogen (BUN) and creatinine, and without proteinuria, should prompt investigation for a renovascular lesion. Standard bypass procedures are usually effective, although the long-term success may be compromised by continuing changes in affected vessels.

A comparison of the effects of 50 MeVd leads to be neutron and cobalt-60 irradiation of the kidneys of rhesus monkeys

Twenty rhesus monkeys had one kidney irradiated (after undergoing unilateral nephrectomies) with one of four doses: 960 or 1080 rads of 50 MeVd leads to Be neutrons, or 2350 or 2700 rads of 60Co. Whereas animals treated with the lower dose of neutrons or 60Co are alive with relatively normal renal function, those treated with the higher dose of neutrons died of radiation nephritis. Animals treated with the higher dose of 60Co developed radiation nephritis but survived. The physiological and histopathological changes of radiation nephritis secondary to neutron irradiation are not qualitatively different from those reported for radiation nephritis secondary to photon irradiation.