May-Thurner Syndrome: Diagnosis, Causes, and Treatment

May-Thurner Syndrome

May-Thurner Syndrome is characterized as a pathological condition where there is compression of the left iliac vein of the pelvis by the iliac artery. Specialists in the field of phlebology describe this condition as difficult to diagnose, as it is provoked by various causes and factors, and can occur against the background of different serious pathologies, both in men and women. May-Thurner Syndrome can manifest as varicocele or varicose veins in the pelvis. If there are suspicions of developing the pathology, it is advisable to consult multidisciplinary diagnostic centers with rich diagnostic and therapeutic facilities. An experienced phlebologist, after conducting a series of examinations, can diagnose the patient and prescribe treatment.


The iliac veins are paired blood vessels located at the level of the sacroiliac joint, providing drainage of blood from the legs to the pelvic area. The veins divide into right and left from the abdominal and aortic vessels, and at the level of the sacrum, they branch into internal and external veins. The latter transition into femoral veins, with the internal veins providing drainage of blood from the organs of the pelvis.

May-Thurner Syndrome in women and men progresses due to compression of the iliac vein, which is located on the left side, by the artery on the right to the spine. In this pathology, there is a disruption of blood flow from the left leg and pelvis. Often, the disease progresses due to advanced atherosclerosis of the vessel walls. Stagnation of blood occurs in the legs and organs of the pelvis (genital organs), leading to the progression of varicose vein expansion.

According to statistics, the right iliac artery compresses the left iliac artery in 22% of cases. Information was obtained from autopsies of deceased individuals, with 430 autopsies conducted. Medical professionals estimate that asymptomatic compression of the left iliac artery is present in 16-20% of the adult population.

Disease Progression
In modern medical practice, three main stages of the disease are distinguished, all of which are discussed in the table below:

Stage Clinical Manifestations
1st stage Proceeds and progresses asymptomatically
Stage 2 Narrowing of the lumen of the iliac veins occurs with the appearance of chronic venous insufficiency
Stage 3 Iliofemoral thromboses occur

The first stage of the disease’s development is characterized by minor changes in the patient’s well-being. Typically, people do not pay attention to them and do not undergo examination. As a result, the dangerous syndrome progresses, leading to serious consequences that pose a threat to life.

Clinical Picture

May-Thurner Syndrome is insufficiently studied and is quite rare in the practice of phlebologists. In the early stages of the pathology’s development, the symptomatic picture may be mild or absent altogether. Manifestations appear later when therapeutic correction is complicated and rarely yields results.

The development of May-Thurner syndrome may be indicated by the following clinical manifestations:

  • Edema of the left leg, accompanied by a change in the color of the skin to a purplish or bluish hue;
  • Intense pain in the affected areas, which is not relieved by analgesics;
  • Visible and palpable varicose veins, which may appear on the testicles in men or the labia majora in women (usually on the affected side);
  • Severe discomfort during physical exertion, including minor activities;
  • Painful menstruation in women, manifested due to varicose veins affecting the pelvic organs;
  • Development of hemorrhoidal nodes.

Men and women affected by this condition often experience problems in their sexual life. This is due to the fact that during increased stress on the organs of the pelvis, pulling pains often occur in the scrotum, which can radiate to the urethra and often intensify after sexual intercourse. Sexual intercourse can significantly intensify or become impossible due to the pain of the nodes.

Before selecting treatment, the specialist must thoroughly examine the patient. For this purpose, comprehensive investigations are conducted to determine the exact diagnosis. Patients are prescribed:

  1. Magnetic resonance imaging (MRI) of the inferior vena cava with contrast enhancement.
  2. Doppler ultrasound scanning of the anatomical structures of the scrotum and veins on each side (for men).
  3. Renal and pelvic phlebography.

The diagnostic scheme may be adjusted by the treating physician depending on the course of the disease and accompanying symptoms in the patient. In addition, comprehensive laboratory testing is conducted to assess the patient’s overall health.


Such a condition has a mechanical cause and can only be corrected surgically. The main goal of radical intervention is to relieve pressure on the iliac artery. In this case, an increase in the elastic properties of the venous wall is achieved, preventing the vein from being compressed between the artery and the spine.

In most cases, stenting is performed to restore patency. A special self-expanding stent with high radial force and a balloon is placed in the area with pathological narrowing. The balloon is inflated to dilate the narrowed area. The stent serves as a framework for the problematic area, ensuring sufficient patency of the narrowed segment. Special instrumentation is used for this procedure because ordinary arterial walls cannot withstand high pressure. The main purpose of the stent is to maintain vein patency in complex anatomical conditions.

If compression of the left iliac vein by the right iliac artery is observed on phlebography, a guidewire needs to be delivered to the inferior vena cava for the surgery. Then, a special stent is inserted along the guidewire and placed at the mouth of the left iliac vein, where it is expanded.

Once the stent is deployed, balloon angioplasty is performed to ensure the dilation of the vein lumen. Stenting of the iliac vein can be complemented by surgical intervention for varicocele and varicose vein expansion of the pelvis. This approach is applied in most cases because May-Thurner Syndrome is considered one of the causes of venous outflow disruption from the pelvic organs.

Patients with recurrent varicocele are recommended testicular vein sclerotherapy, accompanied by immobilization and the introduction of additional intravascular coils. This approach reduces the risk of recurrences. With timely and comprehensive intervention, complete patient recovery is possible. Iliac vein stents remain patent for up to 5 years in 95% of patients who undergo surgical treatment.


If the stent placement during the intervention is done correctly, the patient will not experience any further symptoms of May-Thurner Syndrome. Despite the significant reduction in the risk of disease recurrence, individuals who have undergone surgery need to undergo regular check-ups and remain under the supervision of a phlebologist or vascular surgeon. After stenting, patients may need to take medication to prevent thrombosis development.