Experimental basis of angioinfarction for the treatment of renal hypertension

Collateral circulation and recanalization represent the main problems of organ-ablating renal embolization. Different animal models were used to study the influence of central, peripheral, and capillary occlusion on organ necrosis. The first laboratory experiments were performed to optimize transcatheteral application of the embolization media tested (Gelfoam powder, Histoacryl, Ethibloc). Experiments with the model of a normal rat kidney (n = 400) showed that only capillary embolization homogeneously occluding the entire arterial system resulted in complete organ necrosis, while following central (renal artery ligation) or peripheral (Gelfoam powder) occlusion, areas of intact parenchyma remained. Ethibloc/glucose proved to be the embolization medium best suited for capillary embolization (radiopaque, inert, slow resorption). Studies with the model of unilateral renal hypertension of the rat (n = 146) demonstrated the equivalent therapeutic efficiency on blood pressure of Ethibloc embolization (57% cured, 21% improved) compared to surgical nephrectomy (50% cured, 29% improved), whereas renal artery ligation (85% failed) resulted in minor improvement only. In order to adapt capillary embolization with Ethibloc/glucose to clinical angiographic techniques, we performed angioinfarction of canine kidneys (n = 15): the use of a balloon catheter is mandatory. This guarantees blood stasis during the embolization procedure and avoids embolic reflux. Possible clinical indications of capillary embolization in renal hypertension as a less invasive method are, e.g.: malignant nephrosclerosis; renovascular or glomerulonephritic contracted kidneys, and renal dysplasia. Indications for super-selective vaso-occlusion are renal aneurysms, a-v malformations, and segmental hypoplasia.