Management of left renal vein compression in patients presenting left gonadal vein reflux

Abstract

Background

Compression of left renal vein is an atypical cause of reflux in pelvic veins resulting in pelvic varices that in turn causes frequently lower limb varices in many cases.

Methods

A monocentric study was undertaken to report the treatment and five-year follow up of patients presenting left renal vein compression. Embolization of refluxive gonadal/pelvic veins was performed generally as the initial procedure. Left renal vein stenting was performed in patients presenting haematuria, severe lumbar pain or persistent pelvic/lower limb varices after embolization.

Results

From 462 cases of left renal vein compression, 40 were treated by stenting as first procedure. Four hundred twenty-two were treated by gonadal/pelvic vein embolization and only 15 needed complementary stenting. After follow-up, all cases with haematuria had improved and lumbar pain was eliminated in 81.5%. Patients with recurrent or persistant varices were all improved.

Conclusion

Left renal vein stenting should be considered an effective and safe procedure, with demonstrated durable efficacy and safety and no evidence of restenosis.

Keywords

Venous reflux stents nutcracker syndrome endovenous technique

Introduction

The compression of the left renal vein (LRV) was described for the first time by Grant in 1937, as an entrapment between the superior mesenteric artery and the aorta as ‘a nut between the jaws of a nutcracker’.¹ Other authors had also studied it over the years from different point of views, such as urological or gynaecological approaches.^2–4

Anatomically, LRV can be compressed in the aortomesenteric fork (type A or anterior compression), but also between the lumbar spine and the aorta (type B or retro-aortic compression)⁵ (Figure 1).

Figure 1.

Compression of LRV. The compression of LRV could be of two different types. Type A: LRV is compressed between the aorta (single arrow) and superior mesenteric artery (white arrow), as displayed in CT scan (A1) or selective renal venography (A2). Type B: LRV is compressed between aorta (single arrow) and the lumbar spine (double arrow), as displayed in CT scan (B1) and selective venography (B2). In both cases, a refluxive gonadal vein is identified (asterisk). LRV: left renal vein; CT: computed tomography.

LRV compression causes an increment in the pressure gradient between distal LRV and inferior cava vein. This compression may cause venous hypertension, in renal, gonadal and pelvic veins, with subsequent development of peri-renal, peri-caliceal, ureteral and/or lumbar varicosities. Venous hypertension could also be responsible of wall ruptures in small veins of the proximal urinary tract, producing micro and/or macro haematuria.⁴

Secondary to the compression, a collateral compensatory circulatory system will be formed in the left gonadal vein (LGV), which in turn will generate pelvic and/or lower limb varices (Figure 2), and, sometimes, haemorrhoids, and varicocele and testicular pain in men. Also, LRV compression is frequently responsible of lumbar pain, although there is no clear explanation for it. One possible explanation may be the development of collateral circulation through peri-medullar veins that compress the spinal cord, but also could be consequence of dilatation and hypertension of the renal vein.

Figure 2.

LRV compression and gonadal veins investigated by descending and selective venography. (A) Selective left renal vein venography with massive LGV reflux. (B) Selective proximal venography showing the same dilated and refluxive LGV. (C) Selective distal venography of the same LGV, feeding pelvic varices and internal iliac vein tributary. (D) LRV compression. (E) Refluxive dilated LGV and (F) refluxive LGV feeding lower limb varices through obturator vein in the same patient. LRV: left renal vein; LGV: left gonadal vein.

If the pelvic floor is incompetent, for example after multiple pregnancies, pelvic varices connected with lower limb veins will cause and generate reflux into them, that will be responsible of development of lower limb varicosities, frequently atypical and with higher prevalence in the left lower limb.⁶

LRV compression is considered as the cause of nutcracker syndrome (NS). In the literature, NS is usually identified in two clinical circumstances: patients consulting for urological signs and/or symptoms,^7–11 or female patients consulting for abdominal or gynaecological signs and/or symptoms.^12–16 Most authors underline that a slender body is frequently associated with patients presenting NS.

Aim of the study

The aims of the present study are: (1) to review the management of patients, investigated in our unit from 2005 to 2009 consulting for pelvic congestion syndrome in women or varicocele in men and presenting a LRV compression, (2) to determine what patients needed stenting as a first approach to treat LRV compression, (3) and, finally, to evaluate treatment outcome in those patients during a five-year period follow up.

Methods

In order to identify prevalence of LRV compression and possible related NS, we undertake a single centre retrospective study among all patients consulting for possible chronic venous disease in our institution, from January 2005 to December 2009.

From 19,080 patients, 15,983 were female and 3097 male, with an age span of 25 to 69. In all, 1596 women presented symptoms or signs that could be related to pelvic congestion syndrome (PCS). One hundred fourteen men presented varicocele, symptomatic or not. In both genders, some patients presented in association NS (recurrent haematuria and persistent low back pain).

These patients were investigated according to a dedicated protocol (Figure 3). Different investigations, including ultrasound (US), computed tomograpy (CT), magnetic resonance imaging (MRI) and venography, were used in order to identify LRV compression, as well as dilated tortuous or tubular veins which correspond to pelvic and ovarian varices in women, spermatic vein related to possible LRV compression.

Figure 3.

Schematic diagram of the investigation and treatment protocol in (A) women and (B) men. LRV: left renal vein; LGV: left gonadal vein.

After discarding urological, gynaecological or lumbar spine sign or symptoms related to other causes, our first investigation is transvaginal duplex ultrasound (TVDU), in women. This procedure allows assessing presence, number and size of dilated pelvic veins, but also flow direction and type (that could be either derivative/continuous flow or refluxive/non continuous flow).¹⁷ This investigation does not identify LRV compression, but is essential, in our clinic experience, to identify PCS, that could be secondary to it. However, LRV or iliac vein compression is suspected when continuous flow in five or more dilated pelvic veins per field with diameter of ≥7 mm is present. This compression triggers a compensatory mechanism by spontaneous continuous flow, which is not modified by Valsalva manoeuvre (Figure 4(a)). In absence of compression, the abnormal flow in the dilated pelvic veins is centrifugal, which means refluxive, and is increased by Valsalva manoeuvre (Figure 4(b)).

Figure 4.

TVDU. (A) TVDU, showing dilated pelvic veins with ≥7 mm Φ, in a number ≥5. At VAL, the flow does not increase. Compensatory flow is related to permanent compression. (B) TVDU, showing dilated pelvic veins with ≥7 mm Φ, in a number ≥5. At VAL, the flow does increase. TVDU: Transvaginal Duplex ultrasound; VAL: Valsalva manoeuvre.

As next investigation in women, or first in case of men, an external abdominal (or transparietal) duplex ultrasound (EADU) is performed, to identify a possible compression. This test allows identifying either iliac vein compression or LRV compression, or a combination of both. In presence of LRV compression (Figure 5), EADU allows to measure the diameter of LRV, to check the flow direction in LGV as well as the flow velocity in the vein.^18,19 In our practice, a LRV stenosis is suspected when we observed a diameter ratio between stenosis point and hilum ≥5 mm and dilated LGV with inverted flow, and a peak velocity ratio ≥5.²⁰

Figure 5.

Transparietal Duplex ultrasound anterior LRV compression in aortomesenteric fork: (1) aorta, (2) LRV, (3) inferior vena cava and (4) superior mesenteric artery.

Due to cost, we do not use CT angiogram and/or MR angiography as a routine investigation. Nevertheless, both procedures provide precise anatomic morphology information, particularly in cases when it is difficult to identify the LRV compression type, or when EADU findings were not informative due to patient intestinal gas or severe obesity.

The next step is a selective venography, which allows to visualize iliac vein or/and LRV compression as well as measuring pressure gradients between those veins and vena cava, and identifying gonadal vein refluxes. Besides, treatment could be performed in the same session, minimizing the costs and the patients’ disturbance. Percutaneous vein access was preferentially performed through right basilica or cephalic vein. A femoral vein access was used only in few cases, mainly in presence of retro-aortic LRV where the angulation of LRV complicates the pass of catheters coming from the upper body.

In presence of sign or symptoms related to NS, complementary investigations were undertaken. Haematuria assessment was performed by repeated systematic urine analysis. Lumbar pain was assessed by using a visual analogical scale (VAS) from 1 to 10.²¹ Magnitude of pain is usually considered significant when ≥5 and severe when ≥7. Only in patients presenting recurrent haematuria or severe lumbar pain with a renal-cava pressure gradient of ≥5 mm Hg, stenting was considered as the first approach procedure. In the rest of patients, embolization of refluxive gonadal and pelvic veins was performed as the initial procedure, except in patients presenting recurrent haematuria or severe lumbar pain with a renal-cava pressure gradient of >5 mm, Hg as already stipulated.

For embolization, we use a combination of distal foam sclerotherapy and proximal coiling to close the refluxive veins. Two percent aethoxisclerol foam was generated according to Tessari technique,²² and for coiling, we used controlled-release coils. Injection of contrast was used to assure embolization effectiveness. After treatment, patients were assessed at 1, 3 and 6 months, and then once a year. In patients with later recurrence of symptomatic pelvic/lower limb varices, stenting was evaluated as a complementary procedure.

We use for stenting, as already reported,⁶ a 14–16 mm diameter, 40 mm length Wallstent™ device (Boston Scientific), due to the possibility of re-constraining and its flexibility, giving the possibility to locate it precisely in LRV, without protruding in the cava vein. Morphological immediate results, as well as pressure gradients, are assessed after stenting in the same procedure. Follow-up protocol after stenting consists on physical examinations, US and laboratory investigations, performed at 3, 6 and 12 months after procedure, and since then once a year.

Results

From 1596 female patients investigated with TVDU, we identified 850 cases of continuous or derivative flow, in contrast to 746 cases of refluxive flow. All of these patients has ≥5 dilated pelvic veins per field and with ≥7 mm in size. In all cases, pelvic varicose veins were present.

The investigation with EADU was performed to identify either iliac vein (IV) compression or LRV compression isolated or combined with IV compression. In all, 400 cases presented isolated IV compression, and 450 cases presented LRV compression, combined or not with IV compression.

All this 850 women were investigated by venography, as well as 12 men with EADU examinations in favour of possible LRV compression, in order to confirm the anatomical compression of LRV. In all, 450 LRV compressions were identified in women, and 12 in male patients. Type A compression (anterior compression) had a prevalence of 86.82%, and Type B compression (retro-aortic compression) of 13.18% (Figure 1).

Among the 462 patients (450 women, 12 men) presenting LRV compression, 106 presented it in combination with an IV compression. As haematuria and back pain cannot be related to iliac compression, we considered that LRV compression was responsible of NS signs or/and symptoms. We also take in account gonadal reflux. When gonadal vein reflux was present, we considered that iliac vein compression was not responsible of PCS or varicocele.

Forty patients (36 women and 4 men) were treated by stenting as first step according to our politics mentioned above (recurrent haematuria or/and severe low back pain).

In the 414 remaining women presenting LRV compression without severe and permanent haematuria and lower back pain but PCS with incompetent LGV, we started with embolization as a safe and simple procedure to correct gonadal vein reflux. In all, 401 female patients did not require further interventions, as their PCS or lower limb varices were corrected.

In women presenting persistent PCS that were not improved by embolization, another redo LGV embolization was performed. Thirteen cases were unsuccessful and treated by LRV stenting as second step procedure, all cases with a gradient of ≥5 mm Hg across LRV stenosis.

Four men presenting NS were treated by stenting. When varicocele was not improved by stenting, they were treated by spermatic vein embolization, but LRV stenting was never performed for persistent varicocele in case of unsuccessful embolization. Two men presenting persistent varices of the lower limb after unsuccessful dedicated treatment were treated by LRV stenting (all had a gradient of ≥5 mm Hg across LRV stenosis).

In total, 55 patients (49 women and 6 men) were treated by stenting procedure (Table 1).

Table 1.

Clinical indications for stenting.

Patients (n = 55)	Women (n = 49)	Men (n = 6)	Symptoms and signs
9	8	1	Haematuria
23	22	1	Severe low back pain (≥7 VAS)
8	6	2	Haematuria and severe low back pain
7	7	–	Persistent PCS and pelvic varices related to left gonadal vein recanalization after embolization (gradient pressure ≥5 mm Hg)
8	6	2	Persistent or recurrent lower limb varices after dedicated treatment (gradient pressure ≥5 mm Hg)

VAS: visual analogical scale; PCS: pelvic congestion syndrome.

Postoperative complications consisted in those typically related to endovascular procedures, such as post-procedure pain (in all cases), punctional haematomas at access site (8.9% of cases). Post-stenting results are displayed in Figure 6 and Table 2.

Figure 6.

Comparative of pre- and post-operative status in LRV compression treatment. Pre-operative and post-operative selective venography (A) anterior compression and (B) retro aortic compression. LRV: left renal vein.

Table 2.

Clinical outcome after left renal vein stenting.

Follow up	Patients (%)	Clinicalnumber/total (%)	Laboratory	Phlebography	Abdominal TVUE
Preoperative	55 (100)	31/55 (56.4%) Severe back pain (>7/10 VAS).	17/55 (31%) Haematuria	(see in text)	(see in text)
Immediate postoperative	55 (100)	Mild post-operative left back pain frequent	/	55 (100) Normal morphology and haemodynamics
3 months	55 (100)	16/31 (51.6) Persistent low back pain (>7/10 VAS).^a	0 Haematuria	No	55 (100) Normal.
6 months	55 (100)	16/31 (51.6) Persistent low back pain (>7/10 VAS).	0 Haematuria	No	2/55 (3.64) 2 stent migration (one distal and one proximal)
1 year	55 (100)	5/31 (16.1) Persistent low back pain (>7/10 VAS).	0 Haematuria	No	55 (100) Normal morphology and haemodynamics except 1proximal stent migration No intima hyperplasia
2 years	53 (96.4) 2 lost to F-U	5/30 (16.7) Persistent low back pain (>7/10 VAS).	0 Haematuria	No	53 (100) Normal morphology and haemodynamics except 1proximal stent migration No intima hyperplasia
3 years	52 (94.5) 2 lost to F-U	5/28 (17.9) Persistent low back pain (>7/10 VAS).	0 Haematuria	No	52 (100) Normal morphology and haemodynamics except 1proximal stent migration No intima hyperplasia
4 years	47 (85.5) 8 lost to F-U	5/26 (19.2) Persistent low back pain (>7/10 VAS).	0 Haematuria	No	47 (100) Normal morphology and haemodynamics except 1proximal stent migration No intima hyperplasia
5 years	48 (87.3) 1 patient was back in F-U	5/27 (18.5) Persistent low back pain (5/10 VAS).	0 Haematuria	No	48 (100) Normal morphology and haemodynamics except 1proximal stent migration No intima hyperplasia

After 3 months, we define severe back pain when measured more than 7 on VAS, mean 7.2.

VAS: visual analogic scale (1–10). Bold values: first number is number of patients presenting back pain at the follow-up; second number is number of patients presenting this symptom preoperatively; and between brackets the percentage.

In our series, we found two cases of stent migrations. In both cases, migration was assessed by phlebography. One distal stent migration was treated by complementary stenting in the proximal LRV overlapping the previous stent, with satisfactory result in terms of clinical and venography outcomes. In the other case, a proximal stent migration (Figure 7) was approached by bilateral femoral access in order to try to retrieve the stent, with no success. The stent was firmly inserted in the caval vein and was impossible to retrieve. As the patient presented only moderate left lumbar pain and a short in length LRV, no further intervention was considered.

Figure 7.

Proximal stent migration. (Left) Immediate post-operative venography, after stent release. (Right) Venography performed 6 months after the procedure. The stent had migrated proximally.

Five patients presenting persistent lower limb varices after successful stenting needed complementary treatment that consists on sclerotherapy (n = 2) or phlebectomy (n = 3).

Discussion

LRV compression should be considered as a possible aetiology in patients presenting back pain in both genders. In women complaining of lower abdominal pain, dyspareunia, dysuria and dysmenorrhea, but also pelvic and lower limbs varicose veins a LRV compression may be suspected. The protocol we used for investigating PCS, which includes a TVDU examination, allows identifying continuous flow in pelvic varices. This finding is in favour of a major vein compression, including LRV, which could be confirmed using EADU and venography.

As a resume of our protocol, LRV stenting was performed according to the following criteria. As absolute criteria, we consider macro haematuria and severe lumbar pain (7–10/10 VAS), non-related to other causes. As relative criteria, we consider significant the presence of persistent symptomatic pelvic or lower limbs varices with pressure gradient of ≥5 mm Hg across LRV stenosis, sustained after pelvic or lower limb embolization. Other authors, as Nishimura et al.,²³ use a cut off of 3 mm Hg of pressure gradient to identify a LRV compression, however, in our experience, we rely on numbers given by Nicolaides and Gloviczki,^20,24 as an interventional criteria.

It is admitted that embolization of LGV do not improve haematuria or lumbar pain. However, in our series, it was an efficient treatment for PCS or lower limbs varices, as it could be also related to LRV compression without major consequences. In our series, most of the cases of LRV compression identified by imaging do not presented renal insufficiency or symptoms atributed to NS (haematuria or back pain). This is similar to what happen in IV compression, which in many cases doesn’t causes May–Thurner or Cockett Syndrome.

There is no consensus on how to treat NS. Some authors recommend medical treatment, but others suggest a surgical approach, including LRV transposition, LRV bypass, superior mesenteric artery transposition, kidney auto-transplantation, etc.^16,25–38 In one article, 127 of 139 patients were treated by stenting, all presenting satisfactory clinical outcomes with the exception of one case.³¹

We chose to treat LRV compression by stenting, not only because our large experience in venous stenting but also because we consider that this endovascular treatment is efficient and easily accepted by patients.

We did not encounter major complications or problems in the stenting procedure, and the long-term outcomes were highly satisfactory, both in term of clinical data and imaging (Figure 6).

Stent migration is also mentioned as a complication in other previous works,^31,34–38 finding a 7.8% of stents migrated (10/127 cases). Of a total of 10 stent migrations checked, seven of them occur without clinical complications, two result in Nutcracker recurrence. The last one has major complications, as the stent migrated in the right atrium and the patient needed open cardiac surgery.

A dedicated renal vein stent would probably improve the results and would prevent stent migration. However, we found this postoperative complication as very infrequent, as mentioned above, and we choose to use stent devices with very desirable characteristics, such as flexibility and the possibility to be re-sheathed.

One of the problems of LRV stenting is that is technically a difficult procedure that needs of good expertise. The presence of a short LRV is a stenting contraindication as well as some retro-aortic compression. In these situations, open surgery is recommended. Nevertheless, in our series, none of the LRV compressions found needed to be treated by open surgery.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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