Kidney renal embolization

Technical success of embolization for intrarenal vascular injury is quite high, around 95-100% [42-44]. Typically the recurrence rate is nearly 0% however, in one series a second embolization session was needed in 2 (15%) of 13 patients to fully occlude arteriovenous fistulas and achieve true technical success [44]. An analysis of the effect on renal function of selective embolization for traumatic renal lesions revealed that the mean volume of infarcted kidney was only 6% (range 0-15%) and 1 week postembolization the serum creatinine was normal in all their patients [42]. A series of renal transplants estimated that the maximal volume of infarcted kidney after embolization for biopsy-related injuries was always less than 30% [44]. Also, while renal function dete-... 

Intravenously administered particles with dimensions exceeding 7 /mi (the diameter of the smallest capillaries) will be filtered by the first capillary bed they encounter, usually the lungs, leading to embolism. Intra-arterially administered particles with dimensions exceeding 7 m will be trapped in the closest organ located upstream for example, administration into the mesenteric artery leads to entrapment in the gut, into the renal artery leads to entrapment in the kidney etc. This approach is under investigation to improve the treatment of diseases in the liver. 

Of 207 patients with ischemic stroke, stages III or IV, treated with an intravenous infusion of dextran 40 over 4 days, 9 (4.3%) developed acute renal insufficiency attributable to the dextran. Oliguria occurred after a mean time of 4 (range 3-6) days. The incidence of dextran-induced renal insufficiency was higher in patients with pre-existing impaired kidney function. The high risk of death in the patients who developed renal insufficiency was due to non-renal complications, notably pneumonia and pulmonary embolism (10). 

Gupta BK, Spinowitz BS, Charytan C, Wahl SJ. Cholesterol crystal embolization-associated renal failure after therapy with recombinant tissue-type plasminogen activator. Am J Kidney Dis 1993 21(6) 659-62. 

It should also be noted that when larger vessels are occluded with coils, collateral arteries form relatively rapidly and the distal vascular bed is still perfused but at a lower pressure than before the embolization. This is the theory behind the proximal occlusion of the splenic artery to halt splenic hemorrhage. The use of these coils presupposes the existence of collaterals. For example, embolization of the renal artery will most likely not result in viable renal tissue as the kidney is an end-organ and will not have a collateral arterial system that will support the kidney. 

Fig. 10.6.5. In vivo detectability of 700-900 pm MR marked microspheres after renal artery embolization in the sheep. The left kidney has been emboli-zed with trisacryl-gelatin microspheres containing an MR marker (L), and the right kidney with control trisacryl-gelatin microspheres (R). MRI study of the explanted kidneys was performed 24 h after embolization (3D SPGR Tl, slice thickness). MR marked microspheres are detectable in the cortical area. No control microsphere is detected in the opposite side...

Fig. 9.11a-f. Renal cell carcinoma in the residual kidney with hemorrhage, medically inoperable, a, b Before and after embolization with PVA and coils, c, d Repeat bleeding 1-1.5 years later pre- and postembolization with PVA, Gelfoam, and coils. e,f Repeat bleeding 9 months later pre- and post-Ethanol embolization. The patient survived for 5 more years before he succumbed to diffuse metastatic disease... 

Fig. 4.2a-e. A 73-year-old male patient with renal cell carcinoma, diabetes mellitus and cardiovascular comorbidity. Multiplanar reformat (MPR) in the coronal plane from a pre-interventional multislice spiral CT depicts an eccentric 3.6-cm tumor of the right kidney (arrows) (a). The patient was considered to be at high risk for surgery. Because of the size of the hypervascularized tumor, a tumor embolization was performed prior to RF ablation (b,c). An umbrellashaped RF probe was introduced percutaneously via a lateral approach (d). Four months after RFA the axial CT image shows no contrast enhancement in the tumor area (arrows), corresponding to complete tumor necrosis (e). A sufficient safety margin without contrast enhancement is visible... 

As has been the case with the embolization of other solid organs as described in this chapter, it is recommended that these procedures start with a non-selective abdominal aortogram. Variations in the number of arteries supplying one or both kidneys are numerous and therefore must be documented before attempts at selective catheterization are made. In addition, the angle of origin between the abdominal aorta and renal arteries will help guide catheter selection for catheterization. Aortography is also important to rule out traumatic disruption or dissection of the renal artery before selective catheterization is attempted. Embolization is typically performed as distal as possible, or as close as possible to the site of arterial injury, in order to minimize the amount of devascularized renal parenchyma after the procedure. This typically requires the use of microcatheters and microcoils (Fig. 4.4). 

If good collateral perfusion is unlikely, one then must consider whether one can afford to let the tissue become ischemic. As an example, it would be very reasonable to embolize a peripheral renal artery branch that was injured during a biopsy and sacrifice a small section of renal parenchyma, since it would have negligible effect on renal function. However if the main renal artery was ruptured during PTA, you would not want to embolize this artery except in dire situations since it would sacrifice the entire kidney. 

The vascular supply to the kidney is considered end-organ, and infarction is common after embolization. Therefore, in patients with renal insufficiency or underlying diseases such as tuberous sclerosis or von Recklinghausen s disease, nephron-sparing procedures are vital. Superselective embolization is advisable in all cases of renal artery embolization unless partial or total nephrectomy is planned. 

Renal scarring secondary to vesicoureteral reflux may be the cause of renovascular hypertension. Renal ablation is an alternative to nephrectomy to remove to involved kidney. The selective embolization should be performed with alcohol to prevent collateral revascularization. The efficacy is debated considering that embolization may delay the definitive treatment [26]. Gelfoam and coils are less valuable than alcohol because of collateral revascularization (Fig. 23.9a,b). 

Fig.23.9a,b. Alcohol embolization of atrophic kidney for refractory hypertension, a Selective catheterism of left renal artery, b Renal artery opacification after alcohol embolization shows a complete devascularization of the kidney. Normalization of blood pressure was noted... 

Truche A, Cartier J, Imbert B, Maurizi J, Zaoui P, Carron P. Renal artery embolization after intravenous mercury injection. Kidney Int 2012 82 939. 

Fig. 25.6a-c. Six-meter fall in a 10-year-old boy. Liver and right kidney injury. Enhanced CT (a) performed on admission showed intra- and retroperitoneal effusions. Active bleeding of the right renal artery was demonstrated by CT, then confirmed by angiography (b). Selective embolization of the injured artery was carried out with immediate satisfactory result. Loss of renal function on the right side was detected 1 year later by DMSA scintigraphy (c)... 

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