Renal vascular anomalies

Congenital anomalies of the renal arteries are divided into anomalies of the number, location, shape and structure of the arterial trunks and are detected most frequently among all developmental defects of the kidneys and upper urinary tract.

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Symptoms renal vascular anomalies

Symptoms may be associated with impaired urodynamics of both intra- and extrarenal urinary tracts, manifested by their expansion, pyelonephritis and stone formation. Additional renal arteries in 3.66% of cases are located in the area of ureteral stenosis and significantly increase the risk of urinary tract obstruction. At the site of the vessel-ureter intersection, irreversible sclerotic changes occur in the wall of the latter, leading to the development of hydronephrosis, pyelonephritis and stone formation. Urodynamic impairment is more pronounced if the additional vessel is located anterior to the urinary tract.

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Forms

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Accessory renal artery

An accessory renal artery is the most common type of renal vascular anomaly (84.6% of all detected renal malformations and URT). What is called an "accessory renal artery"? In early works, N.A. Lopatkin wrote: "To avoid confusion, it is advisable to call each vessel that extends from the aorta in addition to the main renal artery an accessory one, and to use the term "multiple arteries" when referring to the entire supply of the kidney in such cases." In later publications, the term "accessory artery" is not used at all, but the term "accessory artery" is used.

Such arteries "have a smaller caliber compared to the main one, go to the upper or lower segment of the kidneys both from the abdominal aorta and from the main trunk of the renal, suprarenal, celiac, diaphragmatic or common iliac artery." There is no clear difference in the interpretation of these concepts. A. V. Ayvazyan and A. M. Voyno-Yasenetsky strictly distinguished the concepts of "multiple main", "accessory" and "perforating" arteries of the kidney. "Multiple main arteries" originate from the aorta and flow into the renal notch. The source of the "accessory arteries" are the common and external celiac, middle suprarenal, lumbar arteries. But they all flow through the renal notch. "Perforating vessels" - penetrating the kidney outside its gates. Another interpretation of the anomalies in the number of renal arteries can be found in the manual "Campbell's urology" (2002). In it, SB Bauer, referring to a large number of works, describes "multiple renal arteries" - that is, more than one main one, "anomalous or aberrant" - originating from any arterial vessel except the aorta and the main renal artery, "accessory" - two or more arterial trunks feeding one renal segment.

Thus, we did not find a unified terminological approach to renal vascular anomalies in quantity and therefore "accessory, or additional, vessel" was considered to be vessels that feed the kidney, in addition to the main artery and originate from the aorta or any vessel, except the main artery. "Aberrant arteries" we called vessels that originate from the renal artery and penetrate the kidney outside the renal sinus. Accessory renal artery can originate from the aorta, renal, diaphragmatic, suprarenal, celiac, iliac vessels and be directed to the upper or lower segment of the kidney. There is no difference in the side of the location of additional arteries.

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Double and multiple renal arteries

Double and multiple renal arteries are a type of renal vascular anomaly in which the kidney receives blood supply from two or more equal-sized trunks.

Additional or multiple arteries are found in the overwhelming majority of observations in a normal kidney and do not lead to pathology, but are quite often combined with other kidney anomalies (dysplastic, double, dystopic, horseshoe kidney, polycystic kidney, etc.).

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Solitary renal artery

A solitary renal artery supplying both kidneys is an extremely rare type of renal vascular anomaly.

Dystopia of the origin of the renal artery

Anomalies of location - anomaly of the renal vessels, the main criterion in determining the type of renal dystopia:

• lumbar - with low origin of the renal artery from the aorta;
• iliac - when originating from the common iliac artery;
• pelvic - where it originates from the internal iliac artery.

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Renal artery aneurysm

Renal artery aneurysm is a vessel dilation due to the absence of muscle fibers in the vessel wall and the presence of only elastic fibers. This anomaly of the renal vessels is quite rare (0.11%). It is usually unilateral. The aneurysm can be located both extrarenally and intrarenally. Clinically, it is manifested by arterial hypertension, diagnosed for the first time in adolescence. It can lead to thromboembolism of the renal arteries with the development of renal infarction.

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Fibromuscular stenosis

Fibromuscular stenosis is a rare vascular anomaly of the renal vessels (0.025%). It is several successive narrowings in the form of a "string of beads" in the middle or distal third of the renal vessel, resulting from excessive development of fibrous and muscular tissue in the wall of the renal artery. It can be bilateral. It manifests itself as difficult-to-correct arterial hypertension of a crisis-free course. Treatment is surgical. The type of surgery depends on the prevalence and localization of the defect.

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Congenital arteriovenous fistulas

Congenital arteriovenous fistulas are less common (0.02%). They are more often localized in arcuate and lobular vessels and can be multiple. They manifest themselves with symptoms of venous hypertension (hematuria, proteinuria, varicocele).

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Congenital changes in the renal veins

Congenital changes in the renal veins can be divided into anomalies of quantity, shape and location, and structure.

Anomalies of the right renal vein are mainly associated with doubling or tripling. The left renal vein, in addition to an increase in quantity, may have an anomaly in shape and position.

According to some data, accessory renal vein and multiple renal veins occur in 18 and 22% of cases, respectively. Accessory renal veins are usually not combined with accessory vessels. Accessory veins, as well as arteries, can cross the ureter, disrupting urodynamics and leading to hydronephrotic transformation. Developmental anomalies of the left renal vein are more common due to the peculiarities of embryogenesis. The right renal vein undergoes virtually no changes during embryogenesis. The left renal vein can pass in front, behind and around the aorta, without entering the inferior vena cava (extracaval entry and congenital absence of the paracaval section).

Structural anomalies include renal vein stenosis. It can be permanent or orthostatic.

The clinical significance of these defects is that they may lead to the development of venous hypertension, and as a consequence, hematuria, varicocele, and menstrual irregularities. The influence of venous anomalies on the risk of developing kidney tumors has been proven.

Previously, the "gold standard" for diagnosing renal vascular anomalies was angiography, but recently it has become possible to diagnose these defects using less invasive methods - digital subtraction angiography, color echo Doppler, MSCT, MRI.

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Treatment renal vascular anomalies

Treatment of renal vascular anomalies is aimed at restoring the outflow of urine from the kidney and involves cutting the additional vessel and, due to the occurrence of an ischemic zone, resection of the kidney, as well as resection of the sclerotically altered zone of the urinary tract and uretero-uretero- or ureteropyelostomy.

If the additional vessel supplies most of the kidney and its resection is impossible, then resection of the narrowed part of the urinary tract and antevasal plasty are performed.