Renal vein stenosis

The accumulated experience of research into the renal venous system allows us not only to establish stenosis of the renal vein, leading to venous congestion in the kidney, but often also to determine the etiological factor of stenosis.

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Causes renal vein stenosis

Renal vein stenosis may occur due to the following reasons.

• Arterial aortomesenteric "tweezers" compressing the renal vein (orthostatic stenosis).
• Acquired renal vein stenosis: nephroptosis, post-traumatic and pyelonephritic pedunculitis, arterial fibrous ring, etc. (permanent stenosis).
• Pathological mobility of the kidney (orthostatic stenosis): unilateral, bilateral.
• Annular left renal vein (permanent stenosis).
• Multiple renal arteries compressing the renal vein (permanent stenosis).
• Retroaortic left renal vein (permanent stenosis).
• Extracaval drainage of the left renal vein, compression by the common iliac artery (permanent stenosis).

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Symptoms renal vein stenosis

Varicocele - varicose veins of the spermatic cord - is one of the most common symptoms of renal vein stenosis in urological practice. High pressure in the renal vein leads to failure of the valves of the testicular vein and the development of a bypass with a reverse flow of venous blood from the renal vein along the testicular into the pampiniform plexus. Then along the external spermatic vein into the common iliac. A compensatory renocaval anastomosis is formed.

Stenosis of the renal vein (or its branch) usually leads to hemodynamic disturbances in the entire venous bed of the kidney. The degree of narrowing, as well as its nature (constant or orthostatic), determines the severity of circulatory disorders in the renal venous system. Compensation of disorders is carried out due to the reservoir-capacitive capabilities of intraorgan venous structures (venous plexuses of the fornices of the calyces) and the transformation of tributaries of the renal vein into bypass outflow pathways.

Congestive venous hypertension in the kidney, slowing of blood flow in the venous segment at the level of the microcirculatory bed, overflow of the fornical plexuses, extraorgan venous collateralization are the pathophysiological basis of certain symptoms and (or) symptom complex of renal vein stenosis (hematuria, varicocele, dysmenorrhea, etc.).

The nature of the relationship between the type of renal vein stenosis and clinical symptoms is obviously as follows. Varicocele most often develops with orthostatic stenosis of the vein (aortomesenteric "tweezers"). Hematuria is not typical for this type of stenosis. Transient and frequently repeated increase in pressure in the renal vein is enough to disrupt blood flow in the testicular vein and cause failure of its valves. The resulting discharge of blood from the renal vein into the pampiniform plexus promotes venous decompression, protects the fornices from excessive overflow, from ruptures and fornical bleeding.

Similar to the development of varicocele in men, stenotic lesions of the renal veins in women lead to disruption of venous renal-ovarian hemodynamics, its perversion and the development of varicose veins of the ovary, descending ovarian varicocele. Characterized by dysmenorrhea, pain in the left half of the abdomen, dyspareunia (pain during sexual intercourse), dysuria, hematuria and proteinuria. In such cases, radiocontrast examination of the venous system of both kidneys is advisable.

When dysmenorrhea is combined with hematuria, oncological alertness requires exclusion of a tumor in the kidney, bladder, and upper urinary tract. In the presence of a tumor in the kidney, pathological arteriovenous shunting in the tumor tissue can lead to the occurrence of fistula hypertension in the renal venous system and the development of pathological reflux from the renal vein to the venous plexus of the ovary, the development of ovarian varicocele, and symptomatic dysmenorrhea. In addition, a kidney tumor, having a polyhormonal potential, can cause ovarian dysfunction.

Hematuria occurs with persistent venous hypertension caused by permanent (organic) stenosis of the vein of acquired or congenital origin. Hematuria that occurs with orthostatic stenosis of the vein of the pathologically mobile right kidney is explained by significantly pronounced and prolonged venous stasis in the right kidney, which, unlike the left, has limited possibilities for bypass venous outflow.

The combination of varicocele and hematuria is possible only in persistent forms of renal vein stenosis.

Diagnostics renal vein stenosis

Diagnosis of renal vein stenosis and determination of its etiology consist of a complex of clinical, laboratory and radiological studies. The specifics of conducting studies and the transition from one method to another depend on the results obtained at the previous stage of diagnosis.

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Clinical diagnosis of renal vein stenosis

First, the presence of clinical signs of impaired venous outflow from the kidney is determined: hematuria, proteinuria, varicocele, dysmenorrhea, etc. The side of the symptom (left, right, both sides), its nature (constant orthostatic), and combination with other symptoms are important. For example, the combination of hematuria and varicocele indicates the possibility of persistent and pronounced narrowing of the vein. The combination of hematuria with hydronephrosis is usually due to the presence of multiple venous trunks or an abnormal annular vein of the kidney. The combination of dysmenorrhea and hematuria indicates stenotic damage to the veins of both kidneys with the simultaneous entry of the right ovarian vein into the right renal vein.

It is advisable to consider clinical manifestations and their evolution in relation to the patient's age. This allows us to predict the probability of one or another cause of renal vein stenosis. Young age is characterized by congenital stenosis factors: arterial "tweezers", multiple arteries compressing the renal vein, annular vein. In older patients, acquired venous lesions due to nephroptosis, arterial fibrous ring, etc. are more often observed.

Family history data on the presence of similar symptoms in the patient's relatives may be important, which suggests a congenital genesis of renal vein stenosis. A history of lumbar or abdominal trauma suggests acquired stenosis. Evaluation of the duration and dynamics of symptoms helps establish the correct etiologic and pathogenetic diagnosis. For example, if orthostatic varicocele that has existed since childhood has become permanent with age, one should think about the transformation of the arterial "tweezers" into an arterial fibrous ring. If the cessation of hematuria in a patient who previously suffered from bleeding from the left kidney coincided with the gradual development of left-sided varicocele, one can assume the formation of venous collaterals that reduced venous congestion in the kidney and changed the clinical picture of the disease.

As experience shows, correct interpretation of clinical symptoms makes it possible not only to suspect renal vein stenosis in a patient, but also to judge its etiology with varying degrees of probability.

The examination begins with an examination of the patient. The presence of varicose veins of the spermatic cord, the side of the lesion, the nature of the varicocele (changes in the filling of the veins of the pampiniform plexus in the horizontal and vertical positions of the patient) are determined. Ivanissevich's maneuver is demonstrative: with the patient in a lying position, the spermatic cord at the level of the outer ring of the inguinal canal is pressed against the pubic bone. In this case, the veins of the cord in the scrotum are not filled; when the patient is transferred to a vertical position, if the compression of the cord is not stopped, the veins do not fill. If the pressure on the cord is stopped, the pampiniform plexus immediately fills and becomes heavier. Already during the examination of the patient, it is possible to assume the nature of hypertension in the renal vein (persistent or transient), to determine the presence and degree of testicular atrophy on the side of the lesion.

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Laboratory diagnostics of renal vein stenosis

Laboratory diagnostic methods include urine analysis according to Almeida-Nechiporenko, determination of daily protein excretion, immunochemical testing of urine and blood.

These indicators are important not so much for establishing a diagnosis (although the degree and nature of proteinuria characterize the severity of renal hemodynamic disorders), but for assessing the result of the treatment undertaken based on the dynamics of protein excretion and changes in the uroproteinogram.

Instrumental diagnostics of renal vein stenosis

Some of the most modern methods of diagnosing renal vein stenosis are 3D spiral bolus computed phlebography with vascular bed reconstruction and high-field MRI with contrast. These technologies allow obtaining comprehensive information about vascular architecture without the use of invasive diagnostic methods.

Widely used color Doppler mapping on modern ultrasound machines by determining retrograde blood flow in the venous bed allows diagnosing so-called subclinical forms of varicocele, especially in preschool and early school-age children.

Renal vein stenosis is diagnosed using venographic studies, which determine the choice of treatment method for this pathology.

Catheterization of the abdominal aorta, inferior vena cava and their branches is performed using the Seldinger method.

Methods of radiocontrast examination of the inferior vena cava and its tributaries

• Lower wreathcavagraphy:
  • non-obstructive - antegrade and retrograde;
  • obstructive - antegrade.
• Renal veno-cavography.
• Venous phase in renal arteriography.
• Non-obstructive:
  • selective retrograde renal venography;
  • selective retrograde renal venography with preliminary interruption or reduction of arterial inflow (using a balloon, a pharmacological drug, an embolizing substance).
• Reflux renal venography with inferior venocavagraphy after renal artery occlusion using a balloon, a pharmacological drug, or an embolizing agent.
• Bilateral reflux renal venography with obstructive inferior cavography.
• Antegrade contrast enhancement of the left renal vein during left-sided testicular venography.