RADIOLOGICAL AND CLINICAL EVALUATION OF RENAL EMBOLIZATION USING EVOH IN DIALYSIS PATIENTS WITH AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE: A PROSPECTIVE LONGITUDINAL OBSERVATIONAL STUDY

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited cystic disorder characterised by the progressive degeneration of the renal parenchyma into cystic formations, with involvement of other organs to varying degrees and incidence (liver, pancreas and brain).

This condition is the most common inherited kidney disorder; in fact, it affects 1 in 400-1,000 births and has a prevalence of 5% among dialysis patients and an incidence of 10% among patients with end-stage renal failure in Europe. It is caused by mutations in the PKD1 or PKD2 genes, which are involved in the production of an abnormal protein that leads to tubular dysplasia.

Cystic degeneration leads to progressive loss of renal function, with the development of hypertension, haematuria and concomitant enlargement of the renal parenchyma. The progression of the disease is precisely marked by an increase in renal volume. The increase in the organ's overall volume is secondary to the development and enlargement of cysts, whilst the proportion of functioning renal parenchyma progressively decreases. For these reasons, the increase in renal volume over time is a powerful predictor of the risk of end-stage renal disease (ESRD).

In addition to its prognostic significance, the enlargement of the kidneys is itself a cause of complications. Indeed, the space occupied within the abdomen can become so extensive as to cause abdominal distension, malaise, pain, loss of appetite, constipation, nausea and vomiting, reduced diaphragmatic movement, breathing difficulties and lower back pain. Overall, patients' quality of life can be severely compromised.

It is not uncommon for the kidneys of patients with ADPKD to occupy the pelvic cavity, the preferred site for kidney transplant placement, which represents the optimal treatment option for the disease once ESRD has been reached. This situation, which is not uncommon, represents a temporary contraindication to kidney transplantation: delaying the procedure also has repercussions on the patient's survival.

The contraindication to transplantation due to anatomical unavailability has so far necessitated surgical nephrectomy (so-called 'debridement nephrectomy') as the sole preventive or pre-transplant therapeutic option. Nephrectomy carries the risks inherent in surgery, including haemorrhage, herniation of the abdominal wall, vascular complications of varying severity-such as arteriovenous fistulas, thrombosis, and vascular wall injury-and the risk of infection. Surgical nephrectomy also has a negative impact on the subsequent possibility of using the peritoneal membrane for dialysis (peritoneal dialysis) and, should blood transfusions be required to correct intraoperative blood loss, contributes to increasing the likelihood of the patient becoming immunised, with the associated risks of reduced availability of compatible donors (so-called hyperimmune patients), and, in any case, a higher risk of acute and chronic rejection, conditions that negatively impact transplant survival.

Given the high risks associated with nephrectomy, a non-invasive alternative has been proposed: reduction of renal volume via transcatheter arterial embolisation.

Renal embolisation can be performed in the Interventional Radiology department via the controlled occlusion of renal vessels using a liquid embolisation agent composed of ethylene vinyl alcohol (EVOH). The literature reports the assessment of embolised patients using CT without contrast medium, but recent technological innovations allow for accurate and precise volumetric assessment of organs using MRI without contrast medium, with reduced inter-operator variability and without the need to subject the patient to ionising radiation during follow-up.