Dr Jason Toniolo

May thurner and renal nutcracker snydrome

May-Thurner Syndrome (MTS)

Pelvic Venous Compression, often associated with May-Thurner Syndrome, is a condition that can lead to chronic pelvic pain. It occurs when the common iliac vein in the pelvis is compressed between the artery that supplies blood to the right leg (the common iliac artery) and the spine. Typically, the left iliac vein is affected, although other nearby veins can also experience compression. This pressure can lead to scar tissue forming inside the vein, reducing blood flow from the legs back to the heart. PVC is common, affecting approximately 20-25% of people, and is more frequently seen in women. While it is a structural variation, it does not necessarily cause symptoms for everyone and is not related to genetic factors or lifestyle. This is important, as many people have an anatomical compression of their iliac vein, and experience no symptoms! Very few people with iliac vein compression should seek intervention. One must meet strict symptomatic and imaging criteria, to be considered for surgery.

Link to Deep Vein Thrombosis (DVT)

In cases where the vein’s narrowing is significant, there is an elevated risk of developing a Deep Vein Thrombosis (DVT), especially when other risk factors are present. Patient who develop a large DVT are offered treatment to remove the clot. Nearly all of these patients will require a stent in their common iliac vein to prevent the clot from re-ocurring.

Signs and Symptoms

PVC signs vary widely and may include:

  • Persistent swelling of the left leg
  • Recurring varicose veins, even after initial treatment
  • Signs of chronic venous insufficiency, such as pigmentation around the ankle, eczema, itching, or ulceration
  • Varicose veins of the vulva (in women) or a varicocoele (in men) – this is associated with both May-Thurner syndrome and gonadal vein incompetence, which can be interconnected conditions.

What to do about MTS

Most cases of May-Thurner syndrome are managed conservatively. However, if a DVT has developed, clot removal followed by stenting of the narrowed area may be necessary. For those experiencing Pelvic Congestion Syndrome (PCS), treatment may involve placing a metal stent in the vein through a small puncture in the groin, usually on the left side, though sometimes both sides are treated. This outpatient procedure, performed under local anesthesia or general anaesthesia, generally takes around 60 minutes.

Symptoms associated with Pelvic Congestion Syndrome (PCS):

  • Heavy menstrual flow
  • A feeling of heaviness or dragging in the pelvis
  • A sense of heaviness in the thighs or hips
  • Back pain
  • Pain during intercourse
  • Discomfort or frequent and urgent urination

As one can imagine, these are very vague symptoms, which can be caused by a vast array of other conditions. It is with great caution, that one should consider these symptoms to be definitely caused by a pelvic vein compression syndrome.

treatment options

Iliac vein stenting

What is Iliac Vein Stenting?

This procedure is performed to address issues resulting from compression of the common iliac vein, which can sometimes affect both the left and right sides. Compression in this area can lead to conditions such as pelvic congestion syndrome, recurrent varicose veins, and chronic venous insufficiency, which may include venous ulcers. Diagnosing these issues typically involves a duplex ultrasound scan, with further confirmation through venography, CT, or MRI.

The Procedure

Conducted in an angiogram suite with X-ray guidance, this procedure can be done with either general anesthesia or sedation combined with local anesthesia. As an outpatient treatment, a needle and small sheaths (tubes) are used to access veins in the right and left groin, allowing the insertion of balloons and stents. The compressed section of the vein is widened with a balloon, and a stent is placed to maintain openness. This procedure usually targets the left side but may involve the right side as well, taking around 45 minutes in total.

 

Possible Complications

  • Blood clots blocking the stent (1-2% likelihood) at 5 years, as well as blockage of the right sided iliac vein (less frequent but possible)
  • Narrowing of the stent – this is variable and can happen years after the stent is inserted. For this reason, patients are put on surveillance programs after their stent is inserted, with ultrasounds performed at set intervals
  • Rare but serious risk of stent migration, which could potentially travel to the heart


When to Seek Help

For any concerns following your procedure, please reach out to your healthcare provider. Additionally, emergency care is available 24/7 at local hospital emergency departments.

Renal Nutcracker Syndrome

Overview of Nutcracker Syndrome

Nutcracker phenomenon is a vascular condition where the left renal vein becomes compressed, most commonly between the aorta and the superior mesenteric artery.

This configuration resembles a nutcracker, giving the condition its name. When this compression leads to clinical symptoms, it is referred to as nutcracker syndrome. The increased pressure within the left renal vein can cause left flank pain and visible blood in the urine (hematuria). Additionally, blood may reroute through collateral veins, causing backflow into surrounding organs and leading to symptoms listed below. 

Although not life-threatening, nutcracker syndrome can significantly impact quality of life for symptomatic patients. Diagnosis often involves imaging studies, and treatment depends on symptom severity, with some patients requiring observation and others needing intervention. 

Causes

Nutcracker syndrome presents with a range of symptoms and lacks standard diagnostic criteria, which can result in delays or misdiagnosis.

Typically, the condition arises due to compression of the left renal vein by the aorta and superior mesenteric artery. Factors that may increase the likelihood of nutcracker syndrome include a lack of abdominal fat, growth spurts in children and adolescents, and certain spinal conditions such as lumbar lordosis. Other causes can include pancreatic cysts or tumors, retroperitoneal tumors, swollen lymph nodes near the abdominal aorta, or an abdominal aortic aneurysm.

Common Signs and Symptoms

  • Pain in the left flank
  • Blood in the urine
  • Discomfort in the lower left abdomen
  • Pelvic and abdominal pain that worsens during menstruation in women
  • Pain and swelling of scrotal veins in men
  • Fatigue and headaches
  • Symptoms that may change with body position

Diagnostic Tests and Imaging

To confirm a diagnosis of nutcracker syndrome or to rule out other conditions, your healthcare provider may review your medical history, conduct a physical examination, and order specific tests, which could include:

  • Urine tests to identify any other possible causes of symptoms
  • Cystoscopy to exclude lower urinary tract conditions
  • Renal biopsy to rule out kidney-related pathologies
  • Doppler ultrasound to visualize blood flow in the compressed vein
  • CT and MRI angiography to assess the narrowing of the renal vein
  • Venography with intravascular ultrasound and pressure measurements to gauge the extent of vein obstruction

Treatment Options

For mild cases, observation may be sufficient, and growth or weight gain may alleviate symptoms in younger patients. In cases of severe symptoms, one of several interventions might be recommended, depending on factors like the patient’s anatomy, age, and likelihood of symptom relief. Options include:

  1. Surgery (open) to reposition the renal vein and relieve compression (renal vein transposition
  2. Endovascular procedures, such as placing a stent in the left renal vein – still an evolving technique, with concerns for stent migration to the heart and lungs limiting its use
  3. Autotransplantation of the left kidney to the pelvic veins (reserved for severe cases not amenable to other interventions). This would rarely be untaken for nutcracker syndrome.
Renal vein transposition and patch
Left renal vein stent

Prognosis and Outcome

Nutcracker syndrome is relatively rare. The key components include flank pain, persistent blood in the urine and likely a dilated and incompetent gonadal vein. Many patients with compression do not have any symptoms and the diagnosis needs to be made with symptoms as well as objective signs of pathology (blood in the urine) and imaging to confirm the diagnosis.